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Coronary Events (coronary + event)
Kinds of Coronary Events Selected AbstractsEuropean Mathematical Genetics Meeting, Heidelberg, Germany, 12th,13th April 2007ANNALS OF HUMAN GENETICS, Issue 4 2007Article first published online: 28 MAY 200 Saurabh Ghosh 11 Indian Statistical Institute, Kolkata, India High correlations between two quantitative traits may be either due to common genetic factors or common environmental factors or a combination of both. In this study, we develop statistical methods to extract the contribution of a common QTL to the total correlation between the components of a bivariate phenotype. Using data on bivariate phenotypes and marker genotypes for sib-pairs, we propose a test for linkage between a common QTL and a marker locus based on the conditional cross-sib trait correlations (trait 1 of sib 1 , trait 2 of sib 2 and conversely) given the identity-by-descent sharing at the marker locus. The null hypothesis cannot be rejected unless there exists a common QTL. We use Monte-Carlo simulations to evaluate the performance of the proposed test under different trait parameters and quantitative trait distributions. An application of the method is illustrated using data on two alcohol-related phenotypes from the Collaborative Study On The Genetics Of Alcoholism project. Rémi Kazma 1 , Catherine Bonaïti-Pellié 1 , Emmanuelle Génin 12 INSERM UMR-S535 and Université Paris Sud, Villejuif, 94817, France Keywords: Gene-environment interaction, sibling recurrence risk, exposure correlation Gene-environment interactions may play important roles in complex disease susceptibility but their detection is often difficult. Here we show how gene-environment interactions can be detected by investigating the degree of familial aggregation according to the exposure of the probands. In case of gene-environment interaction, the distribution of genotypes of affected individuals, and consequently the risk in relatives, depends on their exposure. We developed a test comparing the risks in sibs according to the proband exposure. To evaluate the properties of this new test, we derived the formulas for calculating the expected risks in sibs according to the exposure of probands for various values of exposure frequency, relative risk due to exposure alone, frequencies of latent susceptibility genotypes, genetic relative risks and interaction coefficients. We find that the ratio of risks when the proband is exposed and not exposed is a good indicator of the interaction effect. We evaluate the power of the test for various sample sizes of affected individuals. We conclude that this test is valuable for diseases with moderate familial aggregation, only when the role of the exposure has been clearly evidenced. Since a correlation for exposure among sibs might lead to a difference in risks among sibs in the different proband exposure strata, we also add an exposure correlation coefficient in the model. Interestingly, we find that when this correlation is correctly accounted for, the power of the test is not decreased and might even be significantly increased. Andrea Callegaro 1 , Hans J.C. Van Houwelingen 1 , Jeanine Houwing-Duistermaat 13 Dept. of Medical Statistics and Bioinformatics, Leiden University Medical Center, The Netherlands Keywords: Survival analysis, age at onset, score test, linkage analysis Non parametric linkage (NPL) analysis compares the identical by descent (IBD) sharing in sibling pairs to the expected IBD sharing under the hypothesis of no linkage. Often information is available on the marginal cumulative hazards (for example breast cancer incidence curves). Our aim is to extend the NPL methods by taking into account the age at onset of selected sibling pairs using these known marginal hazards. Li and Zhong (2002) proposed a (retrospective) likelihood ratio test based on an additive frailty model for genetic linkage analysis. From their model we derive a score statistic for selected samples which turns out to be a weighed NPL method. The weights depend on the marginal cumulative hazards and on the frailty parameter. A second approach is based on a simple gamma shared frailty model. Here, we simply test whether the score function of the frailty parameter depends on the excess IBD. We compare the performance of these methods using simulated data. Céline Bellenguez 1 , Carole Ober 2 , Catherine Bourgain 14 INSERM U535 and University Paris Sud, Villejuif, France 5 Department of Human Genetics, The University of Chicago, USA Keywords: Linkage analysis, linkage disequilibrium, high density SNP data Compared with microsatellite markers, high density SNP maps should be more informative for linkage analyses. However, because they are much closer, SNPs present important linkage disequilibrium (LD), which biases classical nonparametric multipoint analyses. This problem is even stronger in population isolates where LD extends over larger regions with a more stochastic pattern. We investigate the issue of linkage analysis with a 500K SNP map in a large and inbred 1840-member Hutterite pedigree, phenotyped for asthma. Using an efficient pedigree breaking strategy, we first identified linked regions with a 5cM microsatellite map, on which we focused to evaluate the SNP map. The only method that models LD in the NPL analysis is limited in both the pedigree size and the number of markers (Abecasis and Wigginton, 2005) and therefore could not be used. Instead, we studied methods that identify sets of SNPs with maximum linkage information content in our pedigree and no LD-driven bias. Both algorithms that directly remove pairs of SNPs in high LD and clustering methods were evaluated. Null simulations were performed to control that Zlr calculated with the SNP sets were not falsely inflated. Preliminary results suggest that although LD is strong in such populations, linkage information content slightly better than that of microsatellite maps can be extracted from dense SNP maps, provided that a careful marker selection is conducted. In particular, we show that the specific LD pattern requires considering LD between a wide range of marker pairs rather than only in predefined blocks. Peter Van Loo 1,2,3 , Stein Aerts 1,2 , Diether Lambrechts 4,5 , Bernard Thienpont 2 , Sunit Maity 4,5 , Bert Coessens 3 , Frederik De Smet 4,5 , Leon-Charles Tranchevent 3 , Bart De Moor 2 , Koen Devriendt 3 , Peter Marynen 1,2 , Bassem Hassan 1,2 , Peter Carmeliet 4,5 , Yves Moreau 36 Department of Molecular and Developmental Genetics, VIB, Belgium 7 Department of Human Genetics, University of Leuven, Belgium 8 Bioinformatics group, Department of Electrical Engineering, University of Leuven, Belgium 9 Department of Transgene Technology and Gene Therapy, VIB, Belgium 10 Center for Transgene Technology and Gene Therapy, University of Leuven, Belgium Keywords: Bioinformatics, gene prioritization, data fusion The identification of genes involved in health and disease remains a formidable challenge. Here, we describe a novel bioinformatics method to prioritize candidate genes underlying pathways or diseases, based on their similarity to genes known to be involved in these processes. It is freely accessible as an interactive software tool, ENDEAVOUR, at http://www.esat.kuleuven.be/endeavour. Unlike previous methods, ENDEAVOUR generates distinct prioritizations from multiple heterogeneous data sources, which are then integrated, or fused, into one global ranking using order statistics. ENDEAVOUR prioritizes candidate genes in a three-step process. First, information about a disease or pathway is gathered from a set of known "training" genes by consulting multiple data sources. Next, the candidate genes are ranked based on similarity with the training properties obtained in the first step, resulting in one prioritized list for each data source. Finally, ENDEAVOUR fuses each of these rankings into a single global ranking, providing an overall prioritization of the candidate genes. Validation of ENDEAVOUR revealed it was able to efficiently prioritize 627 genes in disease data sets and 76 genes in biological pathway sets, identify candidates of 16 mono- or polygenic diseases, and discover regulatory genes of myeloid differentiation. Furthermore, the approach identified YPEL1 as a novel gene involved in craniofacial development from a 2-Mb chromosomal region, deleted in some patients with DiGeorge-like birth defects. Finally, we are currently evaluating a pipeline combining array-CGH, ENDEAVOUR and in vivo validation in zebrafish to identify novel genes involved in congenital heart defects. Mark Broom 1 , Graeme Ruxton 2 , Rebecca Kilner 311 Mathematics Dept., University of Sussex, UK 12 Division of Environmental and Evolutionary Biology, University of Glasgow, UK 13 Department of Zoology, University of Cambridge, UK Keywords: Evolutionarily stable strategy, parasitism, asymmetric game Brood parasites chicks vary in the harm that they do to their companions in the nest. In this presentation we use game-theoretic methods to model this variation. Our model considers hosts which potentially abandon single nestlings and instead choose to re-allocate their reproductive effort to future breeding, irrespective of whether the abandoned chick is the host's young or a brood parasite's. The parasite chick must decide whether or not to kill host young by balancing the benefits from reduced competition in the nest against the risk of desertion by host parents. The model predicts that three different types of evolutionarily stable strategies can exist. (1) Hosts routinely rear depleted broods, the brood parasite always kills host young and the host never then abandons the nest. (2) When adult survival after deserting single offspring is very high, hosts always abandon broods of a single nestling and the parasite never kills host offspring, effectively holding them as hostages to prevent nest desertion. (3) Intermediate strategies, in which parasites sometimes kill their nest-mates and host parents sometimes desert nests that contain only a single chick, can also be evolutionarily stable. We provide quantitative descriptions of how the values given to ecological and behavioral parameters of the host-parasite system influence the likelihood of each strategy and compare our results with real host-brood parasite associations in nature. Martin Harrison 114 Mathematics Dept, University of Sussex, UK Keywords: Brood parasitism, games, host, parasite The interaction between hosts and parasites in bird populations has been studied extensively. Game theoretical methods have been used to model this interaction previously, but this has not been studied extensively taking into account the sequential nature of this game. We consider a model allowing the host and parasite to make a number of decisions, which depend on a number of natural factors. The host lays an egg, a parasite bird will arrive at the nest with a certain probability and then chooses to destroy a number of the host eggs and lay one of it's own. With some destruction occurring, either natural or through the actions of the parasite, the host chooses to continue, eject an egg (hoping to eject the parasite) or abandon the nest. Once the eggs have hatched the game then falls to the parasite chick versus the host. The chick chooses to destroy or eject a number of eggs. The final decision is made by the host, choosing whether to raise or abandon the chicks that are in the nest. We consider various natural parameters and probabilities which influence these decisions. We then use this model to look at real-world situations of the interactions of the Reed Warbler and two different parasites, the Common Cuckoo and the Brown-Headed Cowbird. These two parasites have different methods in the way that they parasitize the nests of their hosts. The hosts in turn have a different reaction to these parasites. Arne Jochens 1 , Amke Caliebe 2 , Uwe Roesler 1 , Michael Krawczak 215 Mathematical Seminar, University of Kiel, Germany 16 Institute of Medical Informatics and Statistics, University of Kiel, Germany Keywords: Stepwise mutation model, microsatellite, recursion equation, temporal behaviour We consider the stepwise mutation model which occurs, e.g., in microsatellite loci. Let X(t,i) denote the allelic state of individual i at time t. We compute expectation, variance and covariance of X(t,i), i=1,,,N, and provide a recursion equation for P(X(t,i)=z). Because the variance of X(t,i) goes to infinity as t grows, for the description of the temporal behaviour, we regard the scaled process X(t,i)-X(t,1). The results furnish a better understanding of the behaviour of the stepwise mutation model and may in future be used to derive tests for neutrality under this model. Paul O'Reilly 1 , Ewan Birney 2 , David Balding 117 Statistical Genetics, Department of Epidemiology and Public Health, Imperial, College London, UK 18 European Bioinformatics Institute, EMBL, Cambridge, UK Keywords: Positive selection, Recombination rate, LD, Genome-wide, Natural Selection In recent years efforts to develop population genetics methods that estimate rates of recombination and levels of natural selection in the human genome have intensified. However, since the two processes have an intimately related impact on genetic variation their inference is vulnerable to confounding. Genomic regions subject to recent selection are likely to have a relatively recent common ancestor and consequently less opportunity for historical recombinations that are detectable in contemporary populations. Here we show that selection can reduce the population-based recombination rate estimate substantially. In genome-wide studies for detecting selection we observe a tendency to highlight loci that are subject to low levels of recombination. We find that the outlier approach commonly adopted in such studies may have low power unless variable recombination is accounted for. We introduce a new genome-wide method for detecting selection that exploits the sensitivity to recent selection of methods for estimating recombination rates, while accounting for variable recombination using pedigree data. Through simulations we demonstrate the high power of the Ped/Pop approach to discriminate between neutral and adaptive evolution, particularly in the context of choosing outliers from a genome-wide distribution. Although methods have been developed showing good power to detect selection ,in action', the corresponding window of opportunity is small. In contrast, the power of the Ped/Pop method is maintained for many generations after the fixation of an advantageous variant Sarah Griffiths 1 , Frank Dudbridge 120 MRC Biostatistics Unit, Cambridge, UK Keywords: Genetic association, multimarker tag, haplotype, likelihood analysis In association studies it is generally too expensive to genotype all variants in all subjects. We can exploit linkage disequilibrium between SNPs to select a subset that captures the variation in a training data set obtained either through direct resequencing or a public resource such as the HapMap. These ,tag SNPs' are then genotyped in the whole sample. Multimarker tagging is a more aggressive adaptation of pairwise tagging that allows for combinations of two or more tag SNPs to predict an untyped SNP. Here we describe a new method for directly testing the association of an untyped SNP using a multimarker tag. Previously, other investigators have suggested testing a specific tag haplotype, or performing a weighted analysis using weights derived from the training data. However these approaches do not properly account for the imperfect correlation between the tag haplotype and the untyped SNP. Here we describe a straightforward approach to testing untyped SNPs using a missing-data likelihood analysis, including the tag markers as nuisance parameters. The training data is stacked on top of the main body of genotype data so there is information on how the tag markers predict the genotype of the untyped SNP. The uncertainty in this prediction is automatically taken into account in the likelihood analysis. This approach yields more power and also a more accurate prediction of the odds ratio of the untyped SNP. Anke Schulz 1 , Christine Fischer 2 , Jenny Chang-Claude 1 , Lars Beckmann 121 Division of Cancer Epidemiology, German Cancer Research Center (DKFZ) Heidelberg, Germany 22 Institute of Human Genetics, University of Heidelberg, Germany Keywords: Haplotype, haplotype sharing, entropy, Mantel statistics, marker selection We previously introduced a new method to map genes involved in complex diseases, using haplotype sharing-based Mantel statistics to correlate genetic and phenotypic similarity. Although the Mantel statistic is powerful in narrowing down candidate regions, the precise localization of a gene is hampered in genomic regions where linkage disequilibrium is so high that neighboring markers are found to be significant at similar magnitude and we are not able to discriminate between them. Here, we present a new approach to localize susceptibility genes by combining haplotype sharing-based Mantel statistics with an iterative entropy-based marker selection algorithm. For each marker at which the Mantel statistic is evaluated, the algorithm selects a subset of surrounding markers. The subset is chosen to maximize multilocus linkage disequilibrium, which is measured by the normalized entropy difference introduced by Nothnagel et al. (2002). We evaluated the algorithm with respect to type I error and power. Its ability to localize the disease variant was compared to the localization (i) without marker selection and (ii) considering haplotype block structure. Case-control samples were simulated from a set of 18 haplotypes, consisting of 15 SNPs in two haplotype blocks. The new algorithm gave correct type I error and yielded similar power to detect the disease locus compared to the alternative approaches. The neighboring markers were clearly less often significant than the causal locus, and also less often significant compared to the alternative approaches. Thus the new algorithm improved the precision of the localization of susceptibility genes. Mark M. Iles 123 Section of Epidemiology and Biostatistics, LIMM, University of Leeds, UK Keywords: tSNP, tagging, association, HapMap Tagging SNPs (tSNPs) are commonly used to capture genetic diversity cost-effectively. However, it is important that the efficacy of tSNPs is correctly estimated, otherwise coverage may be insufficient. If the pilot sample from which tSNPs are chosen is too small or the initial marker map too sparse, tSNP efficacy may be overestimated. An existing estimation method based on bootstrapping goes some way to correct for insufficient sample size and overfitting, but does not completely solve the problem. We describe a novel method, based on exclusion of haplotypes, that improves on the bootstrap approach. Using simulated data, the extent of the sample size problem is investigated and the performance of the bootstrap and the novel method are compared. We incorporate an existing method adjusting for marker density by ,SNP-dropping'. We find that insufficient sample size can cause large overestimates in tSNP efficacy, even with as many as 100 individuals, and the problem worsens as the region studied increases in size. Both the bootstrap and novel method correct much of this overestimate, with our novel method consistently outperforming the bootstrap method. We conclude that a combination of insufficient sample size and overfitting may lead to overestimation of tSNP efficacy and underpowering of studies based on tSNPs. Our novel approach corrects for much of this bias and is superior to the previous method. Sample sizes larger than previously suggested may still be required for accurate estimation of tSNP efficacy. This has obvious ramifications for the selection of tSNPs from HapMap data. Claudio Verzilli 1 , Juliet Chapman 1 , Aroon Hingorani 2 , Juan Pablo-Casas 1 , Tina Shah 2 , Liam Smeeth 1 , John Whittaker 124 Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, UK 25 Division of Medicine, University College London, UK Keywords: Meta-analysis, Genetic association studies We present a Bayesian hierarchical model for the meta-analysis of candidate gene studies with a continuous outcome. Such studies often report results from association tests for different, possibly study-specific and non-overlapping markers (typically SNPs) in the same genetic region. Meta analyses of the results at each marker in isolation are seldom appropriate as they ignore the correlation that may exist between markers due to linkage disequlibrium (LD) and cannot assess the relative importance of variants at each marker. Also such marker-wise meta analyses are restricted to only those studies that have typed the marker in question, with a potential loss of power. A better strategy is one which incorporates information about the LD between markers so that any combined estimate of the effect of each variant is corrected for the effect of other variants, as in multiple regression. Here we develop a Bayesian hierarchical linear regression that models the observed genotype group means and uses pairwise LD measurements between markers as prior information to make posterior inference on adjusted effects. The approach is applied to the meta analysis of 24 studies assessing the effect of 7 variants in the C-reactive protein (CRP) gene region on plasma CRP levels, an inflammatory biomarker shown in observational studies to be positively associated with cardiovascular disease. Cathryn M. Lewis 1 , Christopher G. Mathew 1 , Theresa M. Marteau 226 Dept. of Medical and Molecular Genetics, King's College London, UK 27 Department of Psychology, King's College London, UK Keywords: Risk, genetics, CARD15, smoking, model Recently progress has been made in identifying mutations that confer susceptibility to complex diseases, with the potential to use these mutations in determining disease risk. We developed methods to estimate disease risk based on genotype relative risks (for a gene G), exposure to an environmental factor (E), and family history (with recurrence risk ,R for a relative of type R). ,R must be partitioned into the risk due to G (which is modelled independently) and the residual risk. The risk model was then applied to Crohn's disease (CD), a severe gastrointestinal disease for which smoking increases disease risk approximately 2-fold, and mutations in CARD15 confer increased risks of 2.25 (for carriers of a single mutation) and 9.3 (for carriers of two mutations). CARD15 accounts for only a small proportion of the genetic component of CD, with a gene-specific ,S, CARD15 of 1.16, from a total sibling relative risk of ,S= 27. CD risks were estimated for high-risk individuals who are siblings of a CD case, and who also smoke. The CD risk to such individuals who carry two CARD15 mutations is approximately 0.34, and for those carrying a single CARD15 mutation the risk is 0.08, compared to a population prevalence of approximately 0.001. These results imply that complex disease genes may be valuable in estimating with greater precision than has hitherto been possible disease risks in specific, easily identified subgroups of the population with a view to prevention. Yurii Aulchenko 128 Department of Epidemiology & Biostatistics, Erasmus Medical Centre Rotterdam, The Netherlands Keywords: Compression, information, bzip2, genome-wide SNP data, statistical genetics With advances in molecular technology, studies accessing millions of genetic polymorphisms in thousands of study subjects will soon become common. Such studies generate large amounts of data, whose effective storage and management is a challenge to the modern statistical genetics. Standard file compression utilities, such as Zip, Gzip and Bzip2, may be helpful to minimise the storage requirements. Less obvious is the fact that the data compression techniques may be also used in the analysis of genetic data. It is known that the efficiency of a particular compression algorithm depends on the probability structure of the data. In this work, we compared different standard and customised tools using the data from human HapMap project. Secondly, we investigate the potential uses of data compression techniques for the analysis of linkage, association and linkage disequilibrium Suzanne Leal 1 , Bingshan Li 129 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA Keywords: Consanguineous pedigrees, missing genotype data Missing genotype data can increase false-positive evidence for linkage when either parametric or nonparametric analysis is carried out ignoring intermarker linkage disequilibrium (LD). Previously it was demonstrated by Huang et al (2005) that no bias occurs in this situation for affected sib-pairs with unrelated parents when either both parents are genotyped or genotype data is available for two additional unaffected siblings when parental genotypes are missing. However, this is not the case for consanguineous pedigrees, where missing genotype data for any pedigree member within a consanguinity loop can increase false-positive evidence of linkage. The false-positive evidence for linkage is further increased when cryptic consanguinity is present. The amount of false-positive evidence for linkage is highly dependent on which family members are genotyped. When parental genotype data is available, the false-positive evidence for linkage is usually not as strong as when parental genotype data is unavailable. Which family members will aid in the reduction of false-positive evidence of linkage is highly dependent on which other family members are genotyped. For a pedigree with an affected proband whose first-cousin parents have been genotyped, further reduction in the false-positive evidence of linkage can be obtained by including genotype data from additional affected siblings of the proband or genotype data from the proband's sibling-grandparents. When parental genotypes are not available, false-positive evidence for linkage can be reduced by including in the analysis genotype data from either unaffected siblings of the proband or the proband's married-in-grandparents. Najaf Amin 1 , Yurii Aulchenko 130 Department of Epidemiology & Biostatistics, Erasmus Medical Centre Rotterdam, The Netherlands Keywords: Genomic Control, pedigree structure, quantitative traits The Genomic Control (GC) method was originally developed to control for population stratification and cryptic relatedness in association studies. This method assumes that the effect of population substructure on the test statistics is essentially constant across the genome, and therefore unassociated markers can be used to estimate the effect of confounding onto the test statistic. The properties of GC method were extensively investigated for different stratification scenarios, and compared to alternative methods, such as the transmission-disequilibrium test. The potential of this method to correct not for occasional cryptic relations, but for regular pedigree structure, however, was not investigated before. In this work we investigate the potential of the GC method for pedigree-based association analysis of quantitative traits. The power and type one error of the method was compared to standard methods, such as the measured genotype (MG) approach and quantitative trait transmission-disequilibrium test. In human pedigrees, with trait heritability varying from 30 to 80%, the power of MG and GC approach was always higher than that of TDT. GC had correct type 1 error and its power was close to that of MG under moderate heritability (30%), but decreased with higher heritability. William Astle 1 , Chris Holmes 2 , David Balding 131 Department of Epidemiology and Public Health, Imperial College London, UK 32 Department of Statistics, University of Oxford, UK Keywords: Population structure, association studies, genetic epidemiology, statistical genetics In the analysis of population association studies, Genomic Control (Devlin & Roeder, 1999) (GC) adjusts the Armitage test statistic to correct the type I error for the effects of population substructure, but its power is often sub-optimal. Turbo Genomic Control (TGC) generalises GC to incorporate co-variation of relatedness and phenotype, retaining control over type I error while improving power. TGC is similar to the method of Yu et al. (2006), but we extend it to binary (case-control) in addition to quantitative phenotypes, we implement improved estimation of relatedness coefficients, and we derive an explicit statistic that generalizes the Armitage test statistic and is fast to compute. TGC also has similarities to EIGENSTRAT (Price et al., 2006) which is a new method based on principle components analysis. The problems of population structure(Clayton et al., 2005) and cryptic relatedness (Voight & Pritchard, 2005) are essentially the same: if patterns of shared ancestry differ between cases and controls, whether distant (coancestry) or recent (cryptic relatedness), false positives can arise and power can be diminished. With large numbers of widely-spaced genetic markers, coancestry can now be measured accurately for each pair of individuals via patterns of allele-sharing. Instead of modelling subpopulations, we work instead with a coancestry coefficient for each pair of individuals in the study. We explain the relationships between TGC, GC and EIGENSTRAT. We present simulation studies and real data analyses to illustrate the power advantage of TGC in a range of scenarios incorporating both substructure and cryptic relatedness. References Clayton, D. G.et al. (2005) Population structure, differential bias and genomic control in a large-scale case-control association study. Nature Genetics37(11) November 2005. Devlin, B. & Roeder, K. (1999) Genomic control for association studies. Biometics55(4) December 1999. Price, A. L.et al. (2006) Principal components analysis corrects for stratification in genome-wide association studies. Nature Genetics38(8) (August 2006). Voight, B. J. & Pritchard, J. K. (2005) Confounding from cryptic relatedness in case-control association studies. Public Library of Science Genetics1(3) September 2005. Yu, J.et al. (2006) A unified mixed-model method for association mapping that accounts for multiple levels of relatedness. Nature Genetics38(2) February 2006. Hervé Perdry 1 , Marie-Claude Babron 1 , Françoise Clerget-Darpoux 133 INSERM U535 and Univ. Paris Sud, UMR-S 535, Villejuif, France Keywords: Modifier genes, case-parents trios, ordered transmission disequilibrium test A modifying locus is a polymorphic locus, distinct from the disease locus, which leads to differences in the disease phenotype, either by modifying the penetrance of the disease allele, or by modifying the expression of the disease. The effect of such a locus is a clinical heterogeneity that can be reflected by the values of an appropriate covariate, such as the age of onset, or the severity of the disease. We designed the Ordered Transmission Disequilibrium Test (OTDT) to test for a relation between the clinical heterogeneity, expressed by the covariate, and marker genotypes of a candidate gene. The method applies to trio families with one affected child and his parents. Each family member is genotyped at a bi-allelic marker M of a candidate gene. To each of the families is associated a covariate value; the families are ordered on the values of this covariate. As the TDT (Spielman et al. 1993), the OTDT is based on the observation of the transmission rate T of a given allele at M. The OTDT aims to find a critical value of the covariate which separates the sample of families in two subsamples in which the transmission rates are significantly different. We investigate the power of the method by simulations under various genetic models and covariate distributions. Acknowledgments H Perdry is funded by ARSEP. Pascal Croiseau 1 , Heather Cordell 2 , Emmanuelle Génin 134 INSERM U535 and University Paris Sud, UMR-S535, Villejuif, France 35 Institute of Human Genetics, Newcastle University, UK Keywords: Association, missing data, conditionnal logistic regression Missing data is an important problem in association studies. Several methods used to test for association need that individuals be genotyped at the full set of markers. Individuals with missing data need to be excluded from the analysis. This could involve an important decrease in sample size and a loss of information. If the disease susceptibility locus (DSL) is poorly typed, it is also possible that a marker in linkage disequilibrium gives a stronger association signal than the DSL. One may then falsely conclude that the marker is more likely to be the DSL. We recently developed a Multiple Imputation method to infer missing data on case-parent trios Starting from the observed data, a few number of complete data sets are generated by Markov-Chain Monte Carlo approach. These complete datasets are analysed using standard statistical package and the results are combined as described in Little & Rubin (2002). Here we report the results of simulations performed to examine, for different patterns of missing data, how often the true DSL gives the highest association score among different loci in LD. We found that multiple imputation usually correctly detect the DSL site even if the percentage of missing data is high. This is not the case for the naïve approach that consists in discarding trios with missing data. In conclusion, Multiple imputation presents the advantage of being easy to use and flexible and is therefore a promising tool in the search for DSL involved in complex diseases. Salma Kotti 1 , Heike Bickeböller 2 , Françoise Clerget-Darpoux 136 University Paris Sud, UMR-S535, Villejuif, France 37 Department of Genetic Epidemiology, Medical School, University of Göttingen, Germany Keywords: Genotype relative risk, internal controls, Family based analyses Family based analyses using internal controls are very popular both for detecting the effect of a genetic factor and for estimating the relative disease risk on the corresponding genotypes. Two different procedures are often applied to reconstitute internal controls. The first one considers one pseudocontrol genotype formed by the parental non-transmitted alleles called also 1:1 matching of alleles, while the second corresponds to three pseudocontrols corresponding to all genotypes formed by the parental alleles except the one of the case (1:3 matching). Many studies have compared between the two procedures in terms of the power and have concluded that the difference depends on the underlying genetic model and the allele frequencies. However, the estimation of the Genotype Relative Risk (GRR) under the two procedures has not been studied. Based on the fact that on the 1:1 matching, the control group is composed of the alleles untransmitted to the affected child and on the 1:3 matching, the control group is composed amongst alleles already transmitted to the affected child, we expect a difference on the GRR estimation. In fact, we suspect that the second procedure leads to biased estimation of the GRRs. We will analytically derive the GRR estimators for the 1:1 and 1:3 matching and will present the results at the meeting. Family based analyses using internal controls are very popular both for detecting the effect of a genetic factor and for estimating the relative disease risk on the corresponding genotypes. Two different procedures are often applied to reconstitute internal controls. The first one considers one pseudocontrol genotype formed by the parental non-transmitted alleles called also 1:1 matching of alleles, while the second corresponds to three pseudocontrols corresponding to all genotypes formed by the parental alleles except the one of the case (1:3 matching). Many studies have compared between the two procedures in terms of the power and have concluded that the difference depends on the underlying genetic model and the allele frequencies. However, the estimation of the Genotype Relative Risk (GRR) under the two procedures has not been studied. Based on the fact that on the 1:1 matching, the control group is composed of the alleles untransmitted to the affected child and on the 1:3 matching, the control group is composed amongst alleles already transmitted to the affected child, we expect a difference on the GRR estimation. In fact, we suspect that the second procedure leads to biased estimation of the GRR. We will analytically derive the GRR estimator for the 1:1 and 1:3 matching and will present the results at the meeting. Luigi Palla 1 , David Siegmund 239 Department of Mathematics,Free University Amsterdam, The Netherlands 40 Department of Statistics, Stanford University, California, USA Keywords: TDT, assortative mating, inbreeding, statistical power A substantial amount of Assortative Mating (AM) is often recorded on physical and psychological, dichotomous as well as quantitative traits that are supposed to have a multifactorial genetic component. In particular AM has the effect of increasing the genetic variance, even more than inbreeding because it acts across loci beside within loci, when the trait has a multifactorial origin. Under the assumption of a polygenic model for AM dating back to Wright (1921) and refined by Crow and Felsenstein (1968,1982), the effect of assortative mating on the power to detect genetic association in the Transmission Disequilibrium Test (TDT) is explored as parameters, such as the effective number of genes and the allelic frequency vary. The power is reflected by the non centrality parameter of the TDT and is expressed as a function of the number of trios, the relative risk of the heterozygous genotype and the allele frequency (Siegmund and Yakir, 2007). The noncentrality parameter of the relevant score statistic is updated considering the effect of AM which is expressed in terms of an ,effective' inbreeding coefficient. In particular, for dichotomous traits it is apparent that the higher the number of genes involved in the trait, the lower the loss in power due to AM. Finally an attempt is made to extend this relation to the Q-TDT (Rabinowitz, 1997), which involves considering the effect of AM also on the phenotypic variance of the trait of interest, under the assumption that AM affects only its additive genetic component. References Crow, & Felsenstein, (1968). The effect of assortative mating on the genetic composition of a population. Eugen.Quart.15, 87,97. Rabinowitz,, 1997. A Transmission Disequilibrium Test for Quantitative Trait Loci. Human Heredity47, 342,350. Siegmund, & Yakir, (2007) Statistics of gene mapping, Springer. Wright, (1921). System of mating.III. Assortative mating based on somatic resemblance. Genetics6, 144,161. Jérémie Nsengimana 1 , Ben D Brown 2 , Alistair S Hall 2 , Jenny H Barrett 141 Leeds Institute of Molecular Medicine, University of Leeds, UK 42 Leeds Institute for Genetics, Health and Therapeutics, University of Leeds, UK Keywords: Inflammatory genes, haplotype, coronary artery disease Genetic Risk of Acute Coronary Events (GRACE) is an initiative to collect cases of coronary artery disease (CAD) and their unaffected siblings in the UK and to use them to map genetic variants increasing disease risk. The aim of the present study was to test the association between CAD and 51 single nucleotide polymorphisms (SNPs) and their haplotypes from 35 inflammatory genes. Genotype data were available for 1154 persons affected before age 66 (including 48% before age 50) and their 1545 unaffected siblings (891 discordant families). Each SNP was tested for association to CAD, and haplotypes within genes or gene clusters were tested using FBAT (Rabinowitz & Laird, 2000). For the most significant results, genetic effect size was estimated using conditional logistic regression (CLR) within STATA adjusting for other risk factors. Haplotypes were assigned using HAPLORE (Zhang et al., 2005), which considers all parental mating types consistent with offspring genotypes and assigns them a probability of occurence. This probability was used in CLR to weight the haplotypes. In the single SNP analysis, several SNPs showed some evidence for association, including one SNP in the interleukin-1A gene. Analysing haplotypes in the interleukin-1 gene cluster, a common 3-SNP haplotype was found to increase the risk of CAD (P = 0.009). In an additive genetic model adjusting for covariates the odds ratio (OR) for this haplotype is 1.56 (95% CI: 1.16-2.10, p = 0.004) for early-onset CAD (before age 50). This study illustrates the utility of haplotype analysis in family-based association studies to investigate candidate genes. References Rabinowitz, D. & Laird, N. M. (2000) Hum Hered50, 211,223. Zhang, K., Sun, F. & Zhao, H. (2005) Bioinformatics21, 90,103. Andrea Foulkes 1 , Recai Yucel 1 , Xiaohong Li 143 Division of Biostatistics, University of Massachusetts, USA Keywords: Haploytpe, high-dimensional, mixed modeling The explosion of molecular level information coupled with large epidemiological studies presents an exciting opportunity to uncover the genetic underpinnings of complex diseases; however, several analytical challenges remain to be addressed. Characterizing the components to complex diseases inevitably requires consideration of synergies across multiple genetic loci and environmental and demographic factors. In addition, it is critical to capture information on allelic phase, that is whether alleles within a gene are in cis (on the same chromosome) or in trans (on different chromosomes.) In associations studies of unrelated individuals, this alignment of alleles within a chromosomal copy is generally not observed. We address the potential ambiguity in allelic phase in this high dimensional data setting using mixed effects models. Both a semi-parametric and fully likelihood-based approach to estimation are considered to account for missingness in cluster identifiers. In the first case, we apply a multiple imputation procedure coupled with a first stage expectation maximization algorithm for parameter estimation. A bootstrap approach is employed to assess sensitivity to variability induced by parameter estimation. Secondly, a fully likelihood-based approach using an expectation conditional maximization algorithm is described. Notably, these models allow for characterizing high-order gene-gene interactions while providing a flexible statistical framework to account for the confounding or mediating role of person specific covariates. The proposed method is applied to data arising from a cohort of human immunodeficiency virus type-1 (HIV-1) infected individuals at risk for therapy associated dyslipidemia. Simulation studies demonstrate reasonable power and control of family-wise type 1 error rates. Vivien Marquard 1 , Lars Beckmann 1 , Jenny Chang-Claude 144 Division of Cancer Epidemiology, German Cancer Research Center (DKFZ) Heidelberg, Germany Keywords: Genotyping errors, type I error, haplotype-based association methods It has been shown in several simulation studies that genotyping errors may have a great impact on the type I error of statistical methods used in genetic association analysis of complex diseases. Our aim was to investigate type I error rates in a case-control study, when differential and non-differential genotyping errors were introduced in realistic scenarios. We simulated case-control data sets, where individual genotypes were drawn from a haplotype distribution of 18 haplotypes with 15 markers in the APM1 gene. Genotyping errors were introduced following the unrestricted and symmetric with 0 edges error models described by Heid et al. (2006). In six scenarios, errors resulted from changes of one allele to another with predefined probabilities of 1%, 2.5% or 10%, respectively. A multiple number of errors per haplotype was possible and could vary between 0 and 15, the number of markers investigated. We examined three association methods: Mantel statistics using haplotype-sharing; a haplotype-specific score test; and Armitage trend test for single markers. The type I error rates were not influenced for any of all the three methods for a genotyping error rate of less than 1%. For higher error rates and differential errors, the type I error of the Mantel statistic was only slightly and of the Armitage trend test moderately increased. The type I error rates of the score test were highly increased. The type I error rates were correct for all three methods for non-differential errors. Further investigations will be carried out with different frequencies of differential error rates and focus on power. Arne Neumann 1 , Dörthe Malzahn 1 , Martina Müller 2 , Heike Bickeböller 145 Department of Genetic Epidemiology, Medical School, University of Göttingen, Germany 46 GSF-National Research Center for Environment and Health, Neuherberg & IBE-Institute of Epidemiology, Ludwig-Maximilians University München, Germany Keywords: Interaction, longitudinal, nonparametric Longitudinal data show the time dependent course of phenotypic traits. In this contribution, we consider longitudinal cohort studies and investigate the association between two candidate genes and a dependent quantitative longitudinal phenotype. The set-up defines a factorial design which allows us to test simultaneously for the overall gene effect of the loci as well as for possible gene-gene and gene time interaction. The latter would induce genetically based time-profile differences in the longitudinal phenotype. We adopt a non-parametric statistical test to genetic epidemiological cohort studies and investigate its performance by simulation studies. The statistical test was originally developed for longitudinal clinical studies (Brunner, Munzel, Puri, 1999 J Multivariate Anal 70:286-317). It is non-parametric in the sense that no assumptions are made about the underlying distribution of the quantitative phenotype. Longitudinal observations belonging to the same individual can be arbitrarily dependent on one another for the different time points whereas trait observations of different individuals are independent. The two loci are assumed to be statistically independent. Our simulations show that the nonparametric test is comparable with ANOVA in terms of power of detecting gene-gene and gene-time interaction in an ANOVA favourable setting. Rebecca Hein 1 , Lars Beckmann 1 , Jenny Chang-Claude 147 Division of Cancer Epidemiology, German Cancer Research Center (DKFZ) Heidelberg, Germany Keywords: Indirect association studies, interaction effects, linkage disequilibrium, marker allele frequency Association studies accounting for gene-environment interactions (GxE) may be useful for detecting genetic effects and identifying important environmental effect modifiers. Current technology facilitates very dense marker spacing in genetic association studies; however, the true disease variant(s) may not be genotyped. In this situation, an association between a gene and a phenotype may still be detectable, using genetic markers associated with the true disease variant(s) (indirect association). Zondervan and Cardon [2004] showed that the odds ratios (OR) of markers which are associated with the disease variant depend highly on the linkage disequilibrium (LD) between the variant and the markers, and whether the allele frequencies match and thereby influence the sample size needed to detect genetic association. We examined the influence of LD and allele frequencies on the sample size needed to detect GxE in indirect association studies, and provide tables for sample size estimation. For discordant allele frequencies and incomplete LD, sample sizes can be unfeasibly large. The influence of both factors is stronger for disease loci with small rather than moderate to high disease allele frequencies. A decline in D' of e.g. 5% has less impact on sample size than increasing the difference in allele frequencies by the same percentage. Assuming 80% power, large interaction effects can be detected using smaller sample sizes than those needed for the detection of main effects. The detection of interaction effects involving rare alleles may not be possible. Focussing only on marker density can be a limited strategy in indirect association studies for GxE. Cyril Dalmasso 1 , Emmanuelle Génin 2 , Catherine Bourgain 2 , Philippe Broët 148 JE 2492 , Univ. Paris-Sud, France 49 INSERM UMR-S 535 and University Paris Sud, Villejuif, France Keywords: Linkage analysis, Multiple testing, False Discovery Rate, Mixture model In the context of genome-wide linkage analyses, where a large number of statistical tests are simultaneously performed, the False Discovery Rate (FDR) that is defined as the expected proportion of false discoveries among all discoveries is nowadays widely used for taking into account the multiple testing problem. Other related criteria have been considered such as the local False Discovery Rate (lFDR) that is a variant of the FDR giving to each test its own measure of significance. The lFDR is defined as the posterior probability that a null hypothesis is true. Most of the proposed methods for estimating the lFDR or the FDR rely on distributional assumption under the null hypothesis. However, in observational studies, the empirical null distribution may be very different from the theoretical one. In this work, we propose a mixture model based approach that provides estimates of the lFDR and the FDR in the context of large-scale variance component linkage analyses. In particular, this approach allows estimating the empirical null distribution, this latter being a key quantity for any simultaneous inference procedure. The proposed method is applied on a real dataset. Arief Gusnanto 1 , Frank Dudbridge 150 MRC Biostatistics Unit, Cambridge UK Keywords: Significance, genome-wide, association, permutation, multiplicity Genome-wide association scans have introduced statistical challenges, mainly in the multiplicity of thousands of tests. The question of what constitutes a significant finding remains somewhat unresolved. Permutation testing is very time-consuming, whereas Bayesian arguments struggle to distinguish direct from indirect association. It seems attractive to summarise the multiplicity in a simple form that allows users to avoid time-consuming permutations. A standard significance level would facilitate reporting of results and reduce the need for permutation tests. This is potentially important because current scans do not have full coverage of the whole genome, and yet, the implicit multiplicity is genome-wide. We discuss some proposed summaries, with reference to the empirical null distribution of the multiple tests, approximated through a large number of random permutations. Using genome-wide data from the Wellcome Trust Case-Control Consortium, we use a sub-sampling approach with increasing density to estimate the nominal p-value to obtain family-wise significance of 5%. The results indicate that the significance level is converging to about 1e-7 as the marker spacing becomes infinitely dense. We considered the concept of an effective number of independent tests, and showed that when used in a Bonferroni correction, the number varies with the overall significance level, but is roughly constant in the region of interest. We compared several estimators of the effective number of tests, and showed that in the region of significance of interest, Patterson's eigenvalue based estimator gives approximately the right family-wise error rate. Michael Nothnagel 1 , Amke Caliebe 1 , Michael Krawczak 151 Institute of Medical Informatics and Statistics, University Clinic Schleswig-Holstein, University of Kiel, Germany Keywords: Association scans, Bayesian framework, posterior odds, genetic risk, multiplicative model Whole-genome association scans have been suggested to be a cost-efficient way to survey genetic variation and to map genetic disease factors. We used a Bayesian framework to investigate the posterior odds of a genuine association under multiplicative disease models. We demonstrate that the p value alone is not a sufficient means to evaluate the findings in association studies. We suggest that likelihood ratios should accompany p values in association reports. We argue, that, given the reported results of whole-genome scans, more associations should have been successfully replicated if the consistently made assumptions about considerable genetic risks were correct. We conclude that it is very likely that the vast majority of relative genetic risks are only of the order of 1.2 or lower. Clive Hoggart 1 , Maria De Iorio 1 , John Whittakker 2 , David Balding 152 Department of Epidemiology and Public Health, Imperial College London, UK 53 Department of Epidemiology and Public Health, London School of Hygiene and Tropical Medicine, UK Keywords: Genome-wide association analyses, shrinkage priors, Lasso Testing one SNP at a time does not fully realise the potential of genome-wide association studies to identify multiple causal variants of small effect, which is a plausible scenario for many complex diseases. Moreover, many simulation studies assume a single causal variant and so more complex realities are ignored. Analysing large numbers of variants simultaneously is now becoming feasible, thanks to developments in Bayesian stochastic search methods. We pose the problem of SNP selection as variable selection in a regression model. In contrast to single SNP tests this approach simultaneously models the effect of all SNPs. SNPs are selected by a Bayesian interpretation of the lasso (Tibshirani, 1996); the maximum a posterior (MAP) estimate of the regression coefficients, which have been given independent, double exponential prior distributions. The double exponential distribution is an example of a shrinkage prior, MAP estimates with shrinkage priors can be zero, thus all SNPs with non zero regression coefficients are selected. In addition to the commonly-used double exponential (Laplace) prior, we also implement the normal exponential gamma prior distribution. We show that use of the Laplace prior improves SNP selection in comparison with single -SNP tests, and that the normal exponential gamma prior leads to a further improvement. Our method is fast and can handle very large numbers of SNPs: we demonstrate its performance using both simulated and real genome-wide data sets with 500 K SNPs, which can be analysed in 2 hours on a desktop workstation. Mickael Guedj 1,2 , Jerome Wojcik 2 , Gregory Nuel 154 Laboratoire Statistique et Génome, Université d'Evry, Evry France 55 Serono Pharmaceutical Research Institute, Plan-les-Ouates, Switzerland Keywords: Local Replication, Local Score, Association In gene-mapping, replication of initial findings has been put forwards as the approach of choice for filtering false-positives from true signals for underlying loci. In practice, such replications are however too poorly observed. Besides the statistical and technical-related factors (lack of power, multiple-testing, stratification, quality control,) inconsistent conclusions obtained from independent populations might result from real biological differences. In particular, the high degree of variation in the strength of LD among populations of different origins is a major challenge to the discovery of genes. Seeking for Local Replications (defined as the presence of a signal of association in a same genomic region among populations) instead of strict replications (same locus, same risk allele) may lead to more reliable results. Recently, a multi-markers approach based on the Local Score statistic has been proposed as a simple and efficient way to select candidate genomic regions at the first stage of genome-wide association studies. Here we propose an extension of this approach adapted to replicated association studies. Based on simulations, this method appears promising. In particular it outperforms classical simple-marker strategies to detect modest-effect genes. Additionally it constitutes, to our knowledge, a first framework dedicated to the detection of such Local Replications. Juliet Chapman 1 , Claudio Verzilli 1 , John Whittaker 156 Department of Epidemiology and Public Health, London School of Hygiene and Tropical Medicine, UK Keywords: FDR, Association studies, Bayesian model selection As genomewide association studies become commonplace there is debate as to how such studies might be analysed and what we might hope to gain from the data. It is clear that standard single locus approaches are limited in that they do not adjust for the effects of other loci and problematic since it is not obvious how to adjust for multiple comparisons. False discovery rates have been suggested, but it is unclear how well these will cope with highly correlated genetic data. We consider the validity of standard false discovery rates in large scale association studies. We also show that a Bayesian procedure has advantages in detecting causal loci amongst a large number of dependant SNPs and investigate properties of a Bayesian FDR. Peter Kraft 157 Harvard School of Public Health, Boston USA Keywords: Gene-environment interaction, genome-wide association scans Appropriately analyzed two-stage designs,where a subset of available subjects are genotyped on a genome-wide panel of markers at the first stage and then a much smaller subset of the most promising markers are genotyped on the remaining subjects,can have nearly as much power as a single-stage study where all subjects are genotyped on the genome-wide panel yet can be much less expensive. Typically, the "most promising" markers are selected based on evidence for a marginal association between genotypes and disease. Subsequently, the few markers found to be associated with disease at the end of the second stage are interrogated for evidence of gene-environment interaction, mainly to understand their impact on disease etiology and public health impact. However, this approach may miss variants which have a sizeable effect restricted to one exposure stratum and therefore only a modest marginal effect. We have proposed to use information on the joint effects of genes and a discrete list of environmental exposures at the initial screening stage to select promising markers for the second stage [Kraft et al Hum Hered 2007]. This approach optimizes power to detect variants that have a sizeable marginal effect and variants that have a small marginal effect but a sizeable effect in a stratum defined by an environmental exposure. As an example, I discuss a proposed genome-wide association scan for Type II diabetes susceptibility variants based in several large nested case-control studies. Beate Glaser 1 , Peter Holmans 158 Biostatistics and Bioinformatics Unit, Cardiff University, School of Medicine, Heath Park, Cardiff, UK Keywords: Combined case-control and trios analysis, Power, False-positive rate, Simulation, Association studies The statistical power of genetic association studies can be enhanced by combining the analysis of case-control with parent-offspring trio samples. Various combined analysis techniques have been recently developed; as yet, there have been no comparisons of their power. This work was performed with the aim of identifying the most powerful method among available combined techniques including test statistics developed by Kazeem and Farrall (2005), Nagelkerke and colleagues (2004) and Dudbridge (2006), as well as a simple combination of ,2-statistics from single samples. Simulation studies were performed to investigate their power under different additive, multiplicative, dominant and recessive disease models. False-positive rates were determined by studying the type I error rates under null models including models with unequal allele frequencies between the single case-control and trios samples. We identified three techniques with equivalent power and false-positive rates, which included modifications of the three main approaches: 1) the unmodified combined Odds ratio estimate by Kazeem & Farrall (2005), 2) a modified approach of the combined risk ratio estimate by Nagelkerke & colleagues (2004) and 3) a modified technique for a combined risk ratio estimate by Dudbridge (2006). Our work highlights the importance of studies investigating test performance criteria of novel methods, as they will help users to select the optimal approach within a range of available analysis techniques. David Almorza 1 , M.V. Kandus 2 , Juan Carlos Salerno 2 , Rafael Boggio 359 Facultad de Ciencias del Trabajo, University of Cádiz, Spain 60 Instituto de Genética IGEAF, Buenos Aires, Argentina 61 Universidad Nacional de La Plata, Buenos Aires, Argentina Keywords: Principal component analysis, maize, ear weight, inbred lines The objective of this work was to evaluate the relationship among different traits of the ear of maize inbred lines and to group genotypes according to its performance. Ten inbred lines developed at IGEAF (INTA Castelar) and five public inbred lines as checks were used. A field trial was carried out in Castelar, Buenos Aires (34° 36' S , 58° 39' W) using a complete randomize design with three replications. At harvest, individual weight (P.E.), diameter (D.E.), row number (N.H.) and length (L.E.) of the ear were assessed. A principal component analysis, PCA, (Infostat 2005) was used, and the variability of the data was depicted with a biplot. Principal components 1 and 2 (CP1 and CP2) explained 90% of the data variability. CP1 was correlated with P.E., L.E. and D.E., meanwhile CP2 was correlated with N.H. We found that individual weight (P.E.) was more correlated with diameter of the ear (D.E.) than with length (L.E). Five groups of inbred lines were distinguished: with high P.E. and mean N.H. (04-70, 04-73, 04-101 and MO17), with high P.E. but less N.H. (04-61 and B14), with mean P.E. and N.H. (B73, 04-123 and 04-96), with high N.H. but less P.E. (LP109, 04-8, 04-91 and 04-76) and with low P.E. and low N.H. (LP521 and 04-104). The use of PCA showed which variables had more incidence in ear weight and how is the correlation among them. Moreover, the different groups found with this analysis allow the evaluation of inbred lines by several traits simultaneously. Sven Knüppel 1 , Anja Bauerfeind 1 , Klaus Rohde 162 Department of Bioinformatics, MDC Berlin, Germany Keywords: Haplotypes, association studies, case-control, nuclear families The area of gene chip technology provides a plethora of phase-unknown SNP genotypes in order to find significant association to some genetic trait. To circumvent possibly low information content of a single SNP one groups successive SNPs and estimates haplotypes. Haplotype estimation, however, may reveal ambiguous haplotype pairs and bias the application of statistical methods. Zaykin et al. (Hum Hered, 53:79-91, 2002) proposed the construction of a design matrix to take this ambiguity into account. Here we present a set of functions written for the Statistical package R, which carries out haplotype estimation on the basis of the EM-algorithm for individuals (case-control) or nuclear families. The construction of a design matrix on basis of estimated haplotypes or haplotype pairs allows application of standard methods for association studies (linear, logistic regression), as well as statistical methods as haplotype sharing statistics and TDT-Test. Applications of these methods to genome-wide association screens will be demonstrated. Manuela Zucknick 1 , Chris Holmes 2 , Sylvia Richardson 163 Department of Epidemiology and Public Health, Imperial College London, UK 64 Department of Statistics, Oxford Center for Gene Function, University of Oxford, UK Keywords: Bayesian, variable selection, MCMC, large p, small n, structured dependence In large-scale genomic applications vast numbers of markers or genes are scanned to find a few candidates which are linked to a particular phenotype. Statistically, this is a variable selection problem in the "large p, small n" situation where many more variables than samples are available. An additional feature is the complex dependence structure which is often observed among the markers/genes due to linkage disequilibrium or their joint involvement in biological processes. Bayesian variable selection methods using indicator variables are well suited to the problem. Binary phenotypes like disease status are common and both Bayesian probit and logistic regression can be applied in this context. We argue that logistic regression models are both easier to tune and to interpret than probit models and implement the approach by Holmes & Held (2006). Because the model space is vast, MCMC methods are used as stochastic search algorithms with the aim to quickly find regions of high posterior probability. In a trade-off between fast-updating but slow-moving single-gene Metropolis-Hastings samplers and computationally expensive full Gibbs sampling, we propose to employ the dependence structure among the genes/markers to help decide which variables to update together. Also, parallel tempering methods are used to aid bold moves and help avoid getting trapped in local optima. Mixing and convergence of the resulting Markov chains are evaluated and compared to standard samplers in both a simulation study and in an application to a gene expression data set. Reference Holmes, C. C. & Held, L. (2006) Bayesian auxiliary variable models for binary and multinomial regression. Bayesian Analysis1, 145,168. Dawn Teare 165 MMGE, University of Sheffield, UK Keywords: CNP, family-based analysis, MCMC Evidence is accumulating that segmental copy number polymorphisms (CNPs) may represent a significant portion of human genetic variation. These highly polymorphic systems require handling as phenotypes rather than co-dominant markers, placing new demands on family-based analyses. We present an integrated approach to meet these challenges in the form of a graphical model, where the underlying discrete CNP phenotype is inferred from the (single or replicate) quantitative measure within the analysis, whilst assuming an allele based system segregating through the pedigree. [source] The Predictive Value of Exercise QRS Duration Changes for Post-PTCA Coronary EventsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2003Shai Efrati Background: The sensitivity and predictive values of exercise ECG testing using ST-T criteria after percutaneous transluminal coronary angioplasty (PTCA) are low, precluding its routine use for screening for restenosis. The predictive value of QRS duration criteria during exercise testing (ET) ECG after PTCA for future coronary events has not been reported. The aim of the study was to compare QRS duration changes with ST-T criteria during ET, as a predictor of coronary events after PTCA. Methods: A prospective study of 206 consecutive patients who underwent ET at a mean of 34 ± 14 days after their first PTCA, and were the followed for a mean of 23 ± 9 months. Patients were divided by QRS duration into two groups,Q1: ischemic response (QRS duration prolongation of more than 3 ms relative to the resting duration), and Q2: normal response (QRS duration shortening or without change from resting duration). Patients were also divided by their ST-T response, S1: ischemic response, and S2: normal response. Results: During follow-up 52 patients (58%) experienced restenosis or MI, or underwent CABG,Q1: 44 (85%), Q2: 8(15%) (P < 0.0002), S1: 8 (15%), S2: 44 (85%), (P < 0.641), two patients died,Q1: 1 (1%) and Q2: 1 (1%). For QRS and ST-T, the relative risk of having at least one of the coronary events was 4.02 (CI 2.1,9.9) versus 1.13 (CI 0.8,2.9), respectively. The sensitivity for future coronary events was 85% and 52% and the specificity was 48% and 98% for the QRS and ST-T criteria, respectively. Conclusion: QRS prolongation during peak ET ECG after PTCA is a more sensitive marker than ST-T criteria for detection of patients at risk for later coronary events. [source] Stenting and glycoprotein IIb/IIIa inhibition in patients with acute myocardial infarction undergoing percutaneous coronary intervention: Findings from the global registry of acute coronary events (GRACE)CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2003Gilles Montalescot MD Abstract Stenting and GP IIb/IIIa inhibition are promising adjunctive therapies in PCI. The Global Registry of Acute Coronary Events (GRACE) is a registry of unselected patients with acute coronary syndromes, allowing for the study of treatments in a real-world environment. Data from GRACE patients with AMI who underwent PCI were analyzed. After adjusting for demographics, baseline characteristics, and previous medications, treatment with GP IIb/IIIa inhibitors and a stent and treatment with a stent alone were significant predictors of survival at 6 months. Stents were used in 90.9% of patients. GP IIb/IIIa inhibitors were used in 59.7%; in most cases they were started after the beginning of the procedure. The in-hospital death rate (7.6%) was highest in patients undergoing urgent PCI. Mortality at 6 months following PCI was 14.4% among patients who received neither GP IIb/IIIa inhibitors nor a stent, compared to patients who received both GP IIb/IIIa inhibitors and a stent (7.3%), GP IIb/IIIa inhibitors alone (12.8%), or a stent alone (6.7%) Catheter Cardiovasc Interv 2003;60:360,367. © 2003 Wiley-Liss, Inc. [source] Can we differentiate the low-molecular-weight heparins?CLINICAL CARDIOLOGY, Issue S1 2000Alexander G.G. Turpie M.B., F.A.C.C., F.A.C.P., F.R.C.P.(LOND., F.R.C.P.C., GLASG.) Abstract The low-molecular-weight heparins (LMWHs) have a number of therapeutic advantages, relative to standard unfractionated heparin (UFH). They are readily bioavailable when injected subcutaneously and can be given in fixed doses, allowing for far simpler administration. Several LMWHs are now commercially available, each demonstrating different physical and chemical properties and different activities in animal models of anticoagulation or hemorrhage. in clinical comparisons with placebo in the treatment of unstable coronary artery disease (UCAD), the LMWHs dal-teparin sodium and nadroparin calcium have demonstrated good anticoagulant efficacy. in comparisons with UFH, on the other hand, only enoxaparin has shown superior anticoagulant activity, as reported in the results of the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-wave Coronary Events (ESSENCE) and Thrombolysis in Myocardial Infarction (TIMI) 1 IB trials. However, close scrutiny of the methodology of the clinical trials in UCAD reveals considerable differences in study designs, dosage regimens, duration of administration of active treatments, and the timing and definition of endpoints. Therefore, it would not be scientifically sound to compare results with the different LMWHs based on the current available studies. It is also not possible to draw any conclusions with regard to the relative efficacy of the different LMWHs, since there are no properly-sized comparative data between dal-teparin sodium, enoxaparin sodium, and nadroparin calcium. [source] Haem oxygenase-1 genotype and cardiovascular adverse events in patients with peripheral artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2005P. Dick Abstract Background, A functional GT dinucleotide length polymorphism in the haem oxygenase-1 (HO-1) gene promoter is thought to be involved in the pathogenesis of cardiovascular disease. Short (< 25) (GT)n repeats are suggested to facilitate enhanced HO-1 up-regulation in response to injury and confer potent anti-inflammatory and antioxidative effects. Materials and methods, We investigated the association between the HO-1 GT-polymorphism and cardiovascular outcome in 472 patients with advanced peripheral artery disease. Cardiovascular risk profile and DNA samples for determination of the HO-1 genotype (carrier vs. noncarrier of a short (GT)n repeat allele) were obtained at baseline, and patients were followed for median 21 months for the occurrence of coronary events (myocardial infarction, percutaneous coronary interventions and coronary artery bypass graft), cerebrovascular events (stroke or carotid revascularization) and all-cause mortality. Results, Coronary events occurred in 48 patients (9%), cerebrovascular events in 40 patients (9%) and 59 patients (13%) died. In total, 173 major adverse cardiovascular events (MACE) occurred in 133 patients (28%). Carriers of the short (GT)n repeat allele had a 0·46-fold reduced adjusted hazard ratio for coronary events (P = 0·016) as compared to noncarriers. No significant difference was found for cerebrovascular events, mortality and overall MACE. Conclusion, Apparently, the HO-1 genotype exerts potentially protective effects against coronary adverse events in patients with peripheral artery disease. Homozygous and heterozygous carriers of < 25 (GT)n repeats had lower rates of myocardial infarction, percutaneous coronary interventions and coronary bypass operations compared to patients with longer (GT)n repeats. [source] Using disease risk estimates to guide risk factor interventions: field test of a patient workbook for self-assessing coronary riskHEALTH EXPECTATIONS, Issue 1 2002J. Michael Paterson MSc Objective,To assess the feasibility and acceptability of a patient workbook for self-assessing coronary risk. Design,Pilot study, with post-study physician and patient interviews. Setting and subjects,Twenty southern Ontario family doctors and 40 patients for whom they would have used the workbook under normal practice conditions. Interventions,The study involved convening two sequential groups of family physicians: the first (n=10) attended focus group meetings to help develop the workbook (using algorithms from the Framingham Heart Study); the second (n=20) used the workbook in practice with 40 patients. Follow-up interviews were by interviewer-administered questionnaire. Main outcome measures,Physicians' and patients' opinions of the workbook's format, content, helpfulness, feasibility, and potential for broad application, as well as patients' perceived 10-year risk of a coronary event measured before and after using the workbook. Results,It took an average of 18 minutes of physician time to use the workbook: roughly 7 minutes to introduce it to patients, and about 11 minutes to discuss the results. Assessments of the workbook were generally favourable. Most patients were able to complete it on their own (78%), felt they had learned something (80%) and were willing to recommend it to someone else (98%). Similarly, 19 of 20 physicians found it helpful and would use it in practice with an average of 18% of their patients (range: 1,80%). The workbook helped to correct misperceptions patients had about their personal risk of a coronary event over the next 10 years (pre-workbook (mean (SD) %): 35.2 (16.9) vs. post-workbook: 17.3 (13.5), P < 0.0001; estimate according to algorithm: 10.6 (7.6)). Conclusions,Given a simple tool, patients can and will assess their own risk of CHD. Such tools could help inform otherwise healthy individuals that their risk is increased, allowing them to make more informed decisions about their behaviours and treatment. [source] Effectiveness of brief structured interventions on risk factor modification for patients with coronary heart disease: a systematic reviewINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 4 2007Ritin Fernandez RN MN (Critical care) PhD Candidate Abstract Background, The physical and psychosocial benefits of participation in cardiac rehabilitation following a coronary event have well been established. Despite these benefits there is strong evidence that participation in traditional cardiac rehabilitation programs remains low. Various models of cardiac rehabilitation have been implemented including the use of brief structured interventions to enable modification of coronary risk factors. Objectives, The objective of this review was to determine the effect of brief structured interventions on risk factor modification in patients with coronary heart disease. Search strategy, A literature search was performed using the following databases MEDLINE (1966,2006), CINAHL (1982,2006), EMBASE (1980,current) and up to the Cochrane Controlled Trials Register (Issue 2, 2006 of Cochrane Library). In addition, the reference lists of relevant trials and conference proceedings were also scrutinised. Company representatives, experts and investigators were contacted to elicit further information. Selection criteria, All randomised and quasi-randomised controlled trials that compared the effects of brief structured interventions on risk factor modification in patients with coronary heart disease were considered for inclusion in the review. Data collection and analysis, Eligibility of the trials for inclusion in the review, details of eligible trials and the methodological quality of the trials were assessed independently by two reviewers. Relative risks for dichotomous data and a weighted mean difference for continuous data were calculated with 95% confidence intervals. Where synthesis was inappropriate, trials were considered separately. Main results, Seventeen trials involving a total of 4725 participants were included in the final review: three trials compared the effects of brief structured interventions on diet modification; seven on smoking cessation; and seven on multiple risk factors. Two trials involving 76 patients compared brief structured intervention versus usual care for dietary modification. Although there was a tendency for more participants in the intervention arm to lose weight at the 12-week follow up and achieve target cholesterol levels at the 6-month follow up, these results were not statistically significant. Only one small trial involving 36 patients compared brief structured intervention and extensive intervention for dietary modification and demonstrated a significant reduction in the percentage of energy obtained from fat and saturated fat intake among participants receiving extensive intervention. However, no difference in fish, fruit and vegetable intake between the groups was evident. Six trials involving 2020 patients compared brief structured intervention versus usual care for smoking cessation. There was no difference in the smoking cessation rates at the 3- and 6-week follow up, however, there was evidence of a benefit of brief structured interventions for smoking cessation at the 3-, 6- and 12-month follow up. In the only trial that and compared brief structured intervention and extensive intervention for smoking cessation in 254 participants there was no clear difference of a likelihood of smoking cessation between the two groups. In the seven trials that compared brief structured intervention and usual care for multiple risk factor modification there was evidence of a benefit of the intervention on behavioural changes such as fat intake, weight loss and consequently on reduction in the body mass index, smoking cessation and physical activity among the participants. The findings concerning the effect on blood pressure, blood glucose levels and the lipid profile, however, remain inconclusive. Conclusions, There is suggestive but inconclusive evidence from the trials of a benefit in the use of brief interventions for risk factor modification in patients with coronary heart disease. This review, however, supports the concept that brief interventions for patients with coronary heart disease can have beneficial effects on risk factor modification and consequently on progression of coronary heart disease. Further trials using larger sample sizes need to be undertaken to demonstrate the benefits of brief structured intervention targeted at the modification of single or multiple risk factors. [source] Reduced lung function predicts increased fatality in future cardiac events.JOURNAL OF INTERNAL MEDICINE, Issue 6 2006A population-based study Abstract. Objective., Moderately reduced lung function in apparently healthy subjects has been associated with incidence of coronary events. However, whether lung function is related to the fatality of the future events is unknown. This study explored whether reduced forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) in initially healthy men is related to the fatality of the future coronary events. Design., Prospective cohort study. Setting., Population-based study from Malmö, Sweden. Subjects., A total of 5452 healthy men, 28,61 years of age. Main outcome measures., Incidence of first coronary events was monitored over a mean follow-up of 19 years. The fatality of the future events was studied in relation to FEV and FVC. Results., A total of 589 men suffered a coronary event during follow-up, 165 of them were fatal during the first day. After risk factors adjustment, low FEV or FVC were associated with incidence of coronary events (fatal or nonfatal) and this relationship was most pronounced for the fatal events. Amongst men who subsequently had a coronary event, the case-fatality rates were higher in men with low FEV or FVC. Adjusted for risk factors, the odds ratio for death during the first day was 1.00 (reference), 1.63 (95% CI: 0.9,3.1), 1.86 (1.0,3.5) and 2.06 (1.1,3.9), respectively, for men with FVC in the 4th, 3rd, 2nd, and lowest quartiles (trend: P < 0.05). FEV showed similar relationships with the fatality rates. Conclusion., Apparently healthy men with moderately reduced lung function have higher fatality in future coronary events, with a higher proportion of coronary heart disease deaths and less nonfatal myocardial infarction. [source] Long term effects of exercise training on physical activity level and quality of life in elderly coronary patients , A three- to six-year follow-upPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 1 2003Camilla Hage Abstract Background and Purpose Physical activity and exercise as part of cardiac rehabilitation after an acute coronary event improves exercise capacity and quality of life in most patients. The aim of the present study was to evaluate physical activity level, health-related quality of life (HRQL) and perceived health three to six years after an acute myocardial infarction or an episode of unstable angina pectoris in elderly patients and compare this to earlier follow-up examination data. Method Study design: three to six years (mean 4.4 years) after randomization a questionnaire about physical activity level, HRQL and perceived health was mailed to all subjects alive (n = 93) (response rate 96 Results Since the one-year follow-up examination eight subjects had died: five in the intervention group and three in the control group. At randomization, the level of physical activity level was similar in the two groups. Those in the intervention group improved their level of physical activity significantly over time (p = 0.05) in contrast to the control group. Measurements of HRQL showed no statistical difference between the groups by use of the EuroQol instrument. However, a small advantage for the intervention group measured over time was noted. Conclusion It is important to include elderly patients in cardiac rehabilitation programmes after an acute coronary event, since even a short period of supervised exercise training has the potential to positively influence physical activity level for as long as three to six years. Copyright © 2003 Whurr Publishers Ltd. [source] A peri-operative statin update for non-cardiac surgery.ANAESTHESIA, Issue 1 2008Part I: The effects of statin therapy on atherosclerotic disease, lessons learnt from statin therapy in medical (non-surgical) patients Summary The utility of peri-operative statin therapy is currently considered to be inconclusive. To provide a platform for more meaningful peri-operative statin literature in the future, this is the first of two review articles evaluating peri-operative statin therapy. This review examines the predictors of cardiovascular outcome and therapeutic targets which are established in medical (non-surgical) patients. In patients with stable coronary artery disease at least 4,6 weeks of standard statin therapy are required to realise most of the beneficial cellular and metabolic effects of statin therapy. Low-density lipoprotein-cholesterol reduction is associated with improved survival in these patients. In comparison, patients who sustain an acute coronary event require high-dose statin therapy probably initiated within 24 h with a therapeutic target of C-reactive protein reduction. Withdrawal of statin therapy results in a rapid return to endothelial dysfunction and amplification of the inflammatory process, which may increase cardiovascular risk. [source] Long QT Syndrome in Patients over 40 Years of Age: Increased Risk for LQTS-Related Cardiac Events in Patients with Coronary DiseaseANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2008Edward Sze B.A. Background: Previous studies of long QT syndrome (LQTS) have focused primarily on the clinical course of affected patients up to 40 years of age to avoid the confounding influence of acquired heart disease on LQTS-related cardiac events in this genetic disorder. Methods: Patients were identified as having coronary disease if they had a history of hospitalization for myocardial infarction, coronary angioplasty, coronary artery bypass graft surgery, or were treated with medication for angina. LQTS-related cardiac events included the first occurrence of syncope, aborted cardiac arrest, or sudden cardiac death without evidence suggestive of an acute coronary event. Cox proportional hazards regression modeling was used to analyze the independent contribution of coronary disease to LQTS-related cardiac events. Results: Time-dependent coronary disease was associated with an increased risk of LQTS-related cardiac events (hazard ratio 2.24, 95% confidence interval 1.23,4.07, P = 0.008) after adjustment for syncopal history before age 40, QTc, and gender. Factors such as diabetes and hypertension that increase the risk for coronary disease were not associated with an increased risk for LQTS-related cardiac events. Conclusions: This is the first study to demonstrate that coronary disease augments the risk for LQTS-related cardiac events in LQTS. The findings highlight the need for more focused preventive therapy in LQTS patients above the age of 40. [source] The burden of coronary heart disease in M,ori: population-based estimates for 2000-02AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 4 2009Martin Tobias Abstract Objective: To estimate coronary heart disease (CHD) incidence, prevalence, survival, case fatality and mortality for M,ori, in order to support service planning and resource allocation. Methods: Incidence was defined as first occurrence of a major coronary event, i.e. the sum of first CHD hospital admissions and out-of-hospital CHD deaths in people without a hospital admission for CHD in the preceding five years. Data for the years 2000-02 were sourced from the New Zealand Health Information Service and record linkage was carried out using a unique national identifier, the national health index. Results: Compared to the non-M,ori population, M,ori had both elevated CHD incidence and higher case fatality. Median age at onset of CHD was younger for M,ori, reflecting both higher age specific risks and younger population age structure. The lifetable risk of CHD for M,ori was estimated at 37% (males) and 34% (females), only moderately higher than the corresponding estimates for the non-M,ori population, despite higher M,ori CHD incidence. This reflects the offsetting effect of the higher ,other cause' mortality experienced by M,ori. Median duration of survival with CHD was similar to that of the non-M,ori population for M,ori males but longer for M,ori females, which is most likely related to the earlier age of onset. Conclusions: This study has generated consistent estimates of CHD incidence, prevalence, survival, case fatality and mortality for M,ori in 2000-02. The inequality identified in CHD incidence calls for a renewed effort in primary prevention. The inequality in CHD case fatality calls for improvement in access for M,ori to secondary care services. [source] Influence of socioeconomic and cultural factors on rural healthAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 1 2009John R. Beard Abstract Objective:,To provide a framework for investigating the influence of socioeconomic and cultural factors on rural health. Design:,Discussion paper. Results:,Socioeconomic and cultural factors have long been thought to influence an individual's health. We suggest a framework for characterising these factors that comprises individual-level (e.g. individual socioeconomic status, sex, race) and neighbourhood-level dimensions (population composition, social environment, physical environment) operating both independently and through interaction. Recent spatial research suggests that in rural communities, socioeconomic disadvantage and indigenous status are two of the greatest underlying influences on health status. However, rural communities also face additional challenges associated with access to, and utilisation of, health care. The example is given of procedural angiography for individuals with an acute coronary event. Conclusions:,Socioeconomic and cultural factors specific to rural Australia are key influences on the health of residents. These range from individual-level factors, such as rural stoicism, poverty and substance use norms, to neighbourhood-level social characteristics, such as lack of services, migration out of rural areas of younger community members weakening traditionally high levels of social cohesion, and to environmental factors, such as climate change and access to services. [source] Benefits of statin therapy in patients with special risks: Coronary bypass surgery, stable coronary disease, and acute coronary syndromesCLINICAL CARDIOLOGY, Issue S3 2003W. Virgil Brown M.D. Abstract Several major clinical studies have examined the impact of lipid lowering in patients with and without coronary heart disease and have demonstrated that lowering lipid levels can successfully and significantly delay the onset of cardiovascular events. Although epidemiologic studies and small clinical trials have suggested that more aggressive and sustained lowering of low-density lipoprotein cholesterol (LDL-C) to < 100 mg/dl (2.6 mmol/l) can result in reductions in cardiovascular events in these populations, reducing LDL-C to these concentrations has only recently been shown in larger clinical trials. However, few clinical trials have been conducted in patients with certain special high risks, such as those who have had a recent revascularization procedure or have experienced an acute coronary event. Three trials examined the short- and long-term clinical benefits of aggressive lipid lowering in patients who underwent coronary artery bypass surgery (Post-CABG), were candidates for angioplasty (AVERT), or were hospitalized for acute coronary syndromes (MIRACL). [source] Lipoprotein(a) was an independent predictor for major coronary events in treated hypertensive menCLINICAL CARDIOLOGY, Issue 6 2002Ph.D., Stefan Agewall M.D. Abstract Background and Hypothesis: Lipoprotein(a) may play a part in the development of coronary heart disease. The purpose of this prospective study was to evaluate lipoprotein(a) as a predictor of major coronary events (fatal and nonfatal myocardial infarction and sudden death). Methods: This was a prospective study of 118 men, aged 56 to 77 years, with treated hypertension and at least one additional cardiovascular risk factor (hypercholesterolemia, diabetes mellitus, or smoking) were included in the study. Lipoprotein(a) was measured at entry and major coronary events were followed during follow-up. Results: The mean observation time was 3.0 years. Fourteen patients had a major coronary event during the follow-up period. Subjects with coronary heart disease (previous myocardial infarction, angina pectoris, or major electrocardiographic changes) at entry (n = 27) had significantly higher lipoprotein(a) levels than subjects without (n = 91) known coronary heart disease (p < 0.05). Lipoprotein(a) was a significant predictor for major coronary events (p = 0.033). Furthermore, when coronary disease at entry was included into the Cox regression analysis, lipoprotein(a) was an independent predictorfor major coronary events (p = 0.044). Conclusions: Among treated hypertensive men, lipoprotein(a) was an independent predictor of major coronary events. [source] Haem oxygenase-1 genotype and cardiovascular adverse events in patients with peripheral artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2005P. Dick Abstract Background, A functional GT dinucleotide length polymorphism in the haem oxygenase-1 (HO-1) gene promoter is thought to be involved in the pathogenesis of cardiovascular disease. Short (< 25) (GT)n repeats are suggested to facilitate enhanced HO-1 up-regulation in response to injury and confer potent anti-inflammatory and antioxidative effects. Materials and methods, We investigated the association between the HO-1 GT-polymorphism and cardiovascular outcome in 472 patients with advanced peripheral artery disease. Cardiovascular risk profile and DNA samples for determination of the HO-1 genotype (carrier vs. noncarrier of a short (GT)n repeat allele) were obtained at baseline, and patients were followed for median 21 months for the occurrence of coronary events (myocardial infarction, percutaneous coronary interventions and coronary artery bypass graft), cerebrovascular events (stroke or carotid revascularization) and all-cause mortality. Results, Coronary events occurred in 48 patients (9%), cerebrovascular events in 40 patients (9%) and 59 patients (13%) died. In total, 173 major adverse cardiovascular events (MACE) occurred in 133 patients (28%). Carriers of the short (GT)n repeat allele had a 0·46-fold reduced adjusted hazard ratio for coronary events (P = 0·016) as compared to noncarriers. No significant difference was found for cerebrovascular events, mortality and overall MACE. Conclusion, Apparently, the HO-1 genotype exerts potentially protective effects against coronary adverse events in patients with peripheral artery disease. Homozygous and heterozygous carriers of < 25 (GT)n repeats had lower rates of myocardial infarction, percutaneous coronary interventions and coronary bypass operations compared to patients with longer (GT)n repeats. [source] Coronary Vasoconstrictor Potential of Triptans: A Review of In Vitro Pharmacologic DataHEADACHE, Issue 2004Antoinette MaassenVanDenBrink PhD This article reviews the in vitro pharmacology of the triptans in human isolated coronary arteries. As expected, based on their similar pharmacologic profiles, the triptans cannot be easily differentiated with respect to effects at human isolated coronary arteries. Furthermore, the data show that at therapeutically relevant concentrations, triptans have little potential to cause clinically significant constriction of nondiseased coronary arteries. These data, considered in the context of clinical findings reviewed elsewhere in this supplement, support the conclusion that, while all triptans have the potential to produce small contractions of human isolated coronary arteries, their craniovascular selectivity, when used at therapeutic doses, renders them unlikely to cause serious adverse coronary events in patients with healthy coronary arteries. [source] Cardiovascular Risk Assessment and TriptansHEADACHE, Issue 2004Vasilios Papademetriou MD Identifying the patient for whom triptans are contraindicated because of recognized, diagnosed cardiovascular disease is relatively straightforward. Determining whether a patient with potential unrecognized cardiovascular disease is an appropriate candidate for triptan therapy, however, constitutes a difficult challenge, especially in the absence of a framework for workup of patients. This article discusses the pathophysiology of coronary heart disease and issues involved in assessing cardiovascular risk, and it attempts to provide a framework for cardiovascular risk assessment that can be applied to decisions for prescribing triptans. Current guidelines for cardiovascular risk assessment allow stratification of patients to low, intermediate, or high risk of coronary heart disease events. This framework for risk assessment can be applied to decisions for prescribing triptans. Cardiovascular risk-assessment algorithms discussed elsewhere in this supplement suggest that patients at low risk (1 or no risk factors) of coronary heart disease can be prescribed triptans without the need for a more intensive cardiovascular evaluation. Conversely, patients with established coronary heart disease or coronary heart disease risk equivalents should not be prescribed triptans according to the current prescribing recommendations. Patients at intermediate risk (2 or more risk factors) of coronary heart disease require cardiovascular evaluation before triptans can be prescribed. Current understanding suggests that the risk of future acute coronary events is a function of the absolute number of vulnerable plaques present, a variable that cannot be accurately determined using available technology or risk-prediction models. Cardiovascular risk-assessment guidelines should be evaluated in the context of this limitation. [source] Effects of Helicobacter pylori Eradication on Platelet Activation and Disease Recurrence in Patients with Acute Coronary SyndromesHELICOBACTER, Issue 6 2004J. Ignasi Elizalde ABSTRACT Background., Platelet activation is consistently observed in animal models of Helicobacter pylori infection and could help to explain the alleged epidemiological association between H. pylori and coronary heart disease. Materials and Methods., Ninety-two patients with recent acute coronary syndromes were enrolled. Helicobacter pylori -positive patients were randomized to receive a 7-day course of omeprazole, amoxycillin and metronidazole or placebos. Two months later, H. pylori status was reassessed and baseline parameters, including soluble P-selectin and platelet surface expression of CD62P, CD63 and CD41, were measured again. Patients were followed-up for 1 year or until death or readmission. Results., No baseline differences were observed between H. pylori -positive and -negative cases. Among H. pylori -positive patients, 18 received placebo and 31 received active medication resulting in eradication in 21 cases. No differences were observed in inflammatory parameters or platelet activation markers between patients with persistent or resolved H. pylori infection. However, coronary events recurred at 6 and 12 months, respectively, in 35% and 55% of patients with persisting H. pylori infection compared with 10% and 25% of patients in whom H. pylori was either absent or eradicated (p = .01). Only final H. pylori status [RR 3.07 (95% CI 1.35,98)] and number of coronary risk factors [RR 2.58 (95% CI 1.51,4.41)] were independent predictors of recurrence. Conclusions., Infection with H. pylori does not induce significant platelet activation in patients treated for coronary disease. Helicobacter pylori -infected patients, however, may have an increased risk of recurrence of coronary events. [source] The collaborative atorvastatin diabetes study: preliminary results,INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 1 2005Olwen Glynn Owen Summary The Collaborative AtoRvastatin Diabetes Study (CARDS) is the first large primary prevention study to focus specifically on the role of a statin in patients aged 40,75 years with type 2 diabetes, but no signs or symptoms of pre-existing vascular disease and who had only average or below average cholesterol levels. The trial was a prospective double-blind randomised trial with 2383 type 2 diabetic subjects randomised to either 10-mg atorvastatin daily or placebo. Originally designed to run for 5 years, the trial was terminated over a year early in June 2003 on account of a clear benefit demonstrated for the intervention group. Over half of patients had a low-density lipoprotein cholesterol (LDL-C) below 3.3 mmol/l at entry and a quarter had an LDL-C <2.6 mmol/l. Atorvastatin 10 mg reduced LDL-C by 40% (1.2 mmol/l) on average. Results at 4 years showed a 37% relative risk reduction (p < 0.001) for atorvastatin 10 mg in the primary endpoint (acute coronary heart disease death, fatal or non-fatal myocardial infarction, unstable angina requiring hospital admission, resuscitated cardiac arrest, coronary revascularisation procedures and stroke). Among the secondary endpoints, total mortality was reduced by 27% (p = 0.05), acute coronary events by 36%, coronary revascularisation by 31% and stroke by 48%. The same magnitude of benefit was observed among patients with LDL-C above or below 3 mmol/l. Results observed were against a background where 9% of placebo patients had been permitted to start statin therapy after enrolment and 15% of patients on active treatment had discontinued atorvastatin. The true benefit of the intervention is therefore probably around 25% greater than the intention to treat analysis reports. [source] Effectiveness of nurse-led cardiac clinics in adult patients with a diagnosis of coronary heart diseaseINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 1 2005Tamara Page RN BN HyperbaricNursCert GradDipNSc(HighDep) MNSc Executive summary Background, Coronary heart disease is the major cause of illness and death in Western countries and this is likely to increase as the average age of the population rises. Consumers with established coronary heart disease are at the highest risk of experiencing further coronary events. Lifestyle measures can contribute significantly to a reduction in cardiovascular mortality in established coronary heart disease. Improved management of cardiac risk factors by providing education and referrals as required has been suggested as one way of maintaining quality care in patients with established coronary heart disease. There is a need to ascertain whether or not nurse-led clinics would be an effective adjunct for patients with coronary heart disease to supplement general practitioner advice and care. Objectives, The objective of this review was to present the best available evidence related to nurse-led cardiac clinics. Inclusion criteria, This review considered any randomised controlled trials that evaluated cardiac nurse-led clinics. In the absence of randomised controlled trials, other research designs such as non-randomised controlled trials and before and after studies were considered for inclusion. Participants were adults (18 years and older) with new or existing coronary heart disease. The interventions of interest to the review included education, assessment, consultation, referral and administrative structures. Outcomes measured included adverse event rates, readmissions, admissions, clinical and cost effectiveness, consumer satisfaction and compliance with therapy. Results, Based on the search terms used, 80 papers were initially identified and reviewed for inclusion; full reports of 24 of these papers were retrieved. There were no papers included that addressed cost effectiveness or adverse events; and none addressed the outcome of referrals. A critical appraisal of the 24 remaining papers identified a total of six randomised controlled trials that met the inclusion criteria. Two studies addressed nurse-led clinics for patients diagnosed with angina, one looked at medication administration and the other looked at educational plans. A further four studies compared secondary preventative care with a nurse-led clinic and general practitioner clinic. One specifically compared usual care versus shared care introduced by nurses for patients awaiting coronary artery bypass grafting. Of the remaining three studies, two have been combined in the results section, as they are an interim report and a final report of the same study. Because of inconsistencies in reporting styles and outcome measurements, meta-analysis could not be performed on all outcomes. However, a narrative summary of each study and comparisons of specific outcomes assessed from within each study has been developed. Although not all outcomes obtained statistical significance, nurse-led clinics were at least as effective as general practitioner clinics for most outcomes. Recommendations, The following recommendations are made: ,The use of nurse-led clinics is recommended for patients with coronary heart disease (Level II). ,Utilise nurse-led clinics to increase clinic attendance and follow-up rates (Level II). ,Nurse-led clinics are recommended for patients who require lifestyle changes to decrease their risk of adverse outcomes associated with coronary heart disease (Level II). [source] Therapeutic effect of statin on aortic stenosis: a review with meta-analysisJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 4 2010H. Ge MD Background:, Aortic stenosis (AS) is a common progressive disease. Statins have been hypothesized to delay its progression via pleiotropic mechanisms. However, results of clinical trials focusing on statin therapy in AS patients have been controversial. Objective:, To analyse and summarize the findings in recent statin trials and to discuss the rationale of statin usage in AS populations. Methods:, A comprehensive database search was conducted by two independent reviewers. Controlled trials that compared progression of AS between statin and non-statin therapy published before 31 December 2008 were included. Data were extracted for meta-analysis, to estimate overall effects, if available. Factors that contributed to heterogeneities among the trials were analysed. Results:, The meta-analysis included nine trials with a total of 2947 patients. Statin therapy displayed an overall statistically significant effect on delaying AS progression. The weighted mean difference (statin vs. control) of annual increase of peak aortic-jet velocity was ,0·12 m/s (95% confidence interval ,0·22 to ,0·03); the increase of mean transaortic pressure gradient was ,1·64 mmHg per year (,3·27 to ,0·01); Heterogeneity-analysis suggested that the baseline risk factors and characteristics of the patients, the use of different statins, and the time point to initiate statin therapy, may be important considerations when interpreting the result of individual studies. Conclusion:, Although the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) trial reported negative results in delaying AS progression in low-risk patients, the potential benefits of statins in those with multiple risk factors and their value in preventing future coronary events call for further investigation of different categories of AS patients. [source] Reduced lung function predicts increased fatality in future cardiac events.JOURNAL OF INTERNAL MEDICINE, Issue 6 2006A population-based study Abstract. Objective., Moderately reduced lung function in apparently healthy subjects has been associated with incidence of coronary events. However, whether lung function is related to the fatality of the future events is unknown. This study explored whether reduced forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) in initially healthy men is related to the fatality of the future coronary events. Design., Prospective cohort study. Setting., Population-based study from Malmö, Sweden. Subjects., A total of 5452 healthy men, 28,61 years of age. Main outcome measures., Incidence of first coronary events was monitored over a mean follow-up of 19 years. The fatality of the future events was studied in relation to FEV and FVC. Results., A total of 589 men suffered a coronary event during follow-up, 165 of them were fatal during the first day. After risk factors adjustment, low FEV or FVC were associated with incidence of coronary events (fatal or nonfatal) and this relationship was most pronounced for the fatal events. Amongst men who subsequently had a coronary event, the case-fatality rates were higher in men with low FEV or FVC. Adjusted for risk factors, the odds ratio for death during the first day was 1.00 (reference), 1.63 (95% CI: 0.9,3.1), 1.86 (1.0,3.5) and 2.06 (1.1,3.9), respectively, for men with FVC in the 4th, 3rd, 2nd, and lowest quartiles (trend: P < 0.05). FEV showed similar relationships with the fatality rates. Conclusion., Apparently healthy men with moderately reduced lung function have higher fatality in future coronary events, with a higher proportion of coronary heart disease deaths and less nonfatal myocardial infarction. [source] Initial and Follow-Up Results of the European SeaquenceÔ Coronary Stent RegistryJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2004MARTIAL HAMON M.D. The primary objective of the present study was to assess the feasibility and the safety of the SeaquenceÔ stent (CathNet-Science) deployment for the treatment of coronary artery disease and the event-free survival of patients treated with this coronary stent. The study was conducted as a multicenter, prospective, observational registry. Patients with stable or unstable angina pectoris who were candidates for percutaneous coronary intervention with elective stenting of one single de novo lesion in a native coronary artery ,3 mm in diameter were included in the study. Clinical follow-up was performed at 1 month and 9 months. Major adverse coronary events (MACE), that is, cardiac death, myocardial infarction, and target vessel revascularization (re-PTCA or CABG), were recorded over a period of 9 months. Using this stent, a 99% in-hospital success rate was achieved. A total of 17 patients presented MACE (8.7%) during the whole follow-up period and target lesion revascularization was needed for 14 (7.1%) patients. Using multivariate analysis only some clinical parameters (patients treated for unstable angina, with a history of CABG or of female gender) were found as independent predictors of MACE after coronary stenting. Procedural related factors, angiographic characteristics, or reference diameter were not found to influence clinical outcome. Because the study was performed in patients with a high proportion of complex lesions (relative high-risk nonselected population with nearly one third calcified lesions, many long and type B2 and C lesions) we can conclude that the coronary SeaquenceÔ stent can be considered as a stent of reference in routine practice. (J Interven Cardiol 2004;17:9,15) [source] Improving Compliance in Your Dyslipidemic Patient: An Evidence-based ApproachJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 5 2001Diane M. Becker RN Purpose To synthesize the evidence from landmark clinical studies of lipid-lowering pharma-cotherapy and nurse management of hyperlipidemia, discuss issues related to nonadherence, and proposes strategies for achieving long-term cholesterol control. Data Sources All publications of lipid-lowering clinical trials related to pharmacotherapy for dyslipidemias were accessed from a thorough Medline Search and reviewed by two nurse experts. Conclusions Randomized controlled studies provide com-pelling evidence that reduction of blood cho-lesterol with pharmacotherapy reduces both first and subsequent coronary events. Nonetheless, inadequate provider and patient adherence to guidelines for lipid lowering remains prevalent. Studies show that nurses provide safe and effective care for patients with abnormal lipids. Implications This article assists nurse practitioners in playing an active role in the implementation of the National Cholesterol Education Program Adult Treatment Panel III Report to be released in Spring 2001, where a strong emphasis will be placed on multidisciplinary approaches and adherence. [source] Latest news and product developmentsPRESCRIBER, Issue 8 2007Article first published online: 23 JUL 200 Lamotrigine for partial, valproate for generalised A large UK trial has shown that lamotrigine is the most effective choice in the treatment of partial epilepsy (Lancet 2007;369: 1000-15). The SANAD trial, commissioned by the National Institute for Health Research's Health Technology Assessment programme, randomised 1721 patients (for whom carbamazepine monotherapy would have been the treatment of choice) to treatment with carbamazepine, gabapentin, lamotrigine, oxcarbazepine (Trileptal) or topiramate (Topamax). Lamotrigine was associated with a longer time to treatment failure, though time to 12-month remission favoured carbamazepine. Over four years' follow-up, lamotrigine was numerically but not significantly superior. The authors concluded lamotrigine is clinically superior to carbamazepine for partial epilepsy A second arm of the trial, yet to be published, evaluated the treatment of generalised epilepsy and found valproate to be clinically most effective, though topiramate was cost effective for some patients. Chronic pain common in nursing homes Most residents in nursing homes say they have long- term pain but only one in seven say a health professional has ever discussed its treatment with them, according to a report by the Patients' Association (www.patients-association.org.uk). Pain in Older People ,A Hidden Problem was a qualitative study of 77 older residents in care homes in England. Most were frail and suffered long-term illness. The study found that 85 per cent of residents said they were often troubled by aches or pains and these lasted over a year in 74 per cent. Most described their pain as moderate (33 per cent) or severe (38 per cent) but 8 per cent said it was excruciating. Many reported limitations on mobility and social activities despite a high level of stoicism. All but one were taking medication to relive pain; one-third experienced adverse effects but 78 per cent believed drugs offered the most effective treatment. One-quarter said a doctor or nurse had discussed how to stop their pain worsening, and 15 per cent said they had discussed how to treat their pain. Visits from GPs appeared to be uncommon. Atherothrombotic events despite treatment Between one in five and one in seven of high-risk patients experience atherothrombotic events despite evidence-based treatment, the REACH study has shown (J Am Med Assoc 2007;297:1197-1206). REACH (REduction of Atherothrombosis for Continued Health) is an international observational study involving 68 236 patients with atherothrombotic disease or at least three risk factors. Most were taking conventional evidence-based medication. After one year, the incidence of the combined endpoint of cardiovascular death, myocardial infarction, stroke or hospitalisation for atherothrombotic events was approximately 15 per cent for patients with coronary artery disease or cardiovascular disease, and 21 per cent in patients with peripheral artery disease and established coronary disease. Event rates increased with the number of vascular beds affected, rising to 26 per cent in patients with three symptomatic arterial disease locations. Extended CD prescribing by nurses and pharmacists The Medicines and Healthcare products Regulatory Agency (MHRA) is consulting on expanding the prescribing of controlled drugs (CDs) by nonmedical prescribers. Currently, nurse independent prescribers can prescribe 12 CDs, including diamorphine and morphine, but pharmacist independent prescribers may not prescribe any CDs. The proposal is to allow both professions to prescribe any CDs within their competence, with the exception of cocaine, diamorphine or dipipanone for the management of addiction. The closing date for consultation is 15 June. Consultation is also underway on expanding the range of CDs nurses and pharmacists can prescribe under a patient group direction (PGD), and their use for pain relief. The closing date for consultation is 20 April. Intrinsa: transdermal testosterone for women A transdermal formulation of testosterone has been introduced for the treatment of low sexual desire associated with distress in women who have experienced an early menopause following hysterectomy involving a bilateral oophorectomy and are receiving concomitant oestrogen therapy. Manufacturer Procter & Gamble says that Intrinsa, a twice-weekly patch, delivers testosterone 300µg every 24 hours, achieving premenopausal serum testosterone levels. Clinical trials showed that Intrinsa reduced distress in 65-68 per cent and increased satisfying sexual activity in 51-74 per cent of women. A month's treatment (eight patches) costs £28.00. Fish oil for secondary ,not primary ,prevention of CHD Supplementing statin therapy with eicosapentaenoic acid (EPA) reduces the risk of major coronary events in patients with coronary heart disease (CHD) ,but not in patients with no history of CHD Lancet 2007;369:1090-8). The five-year study in 18 645 patients with total cholesterol levels of 6.5mmol per litre or greater found that the incidence of sudden cardiac death, fatal and nonfatal myocardial infarction in CHD patients treated with EPA plus a statin was 8.7 per cent compared with 10.7 per cent with a statin alone (relative risk reduction 19 per cent). A similar relative risk reduction in patients with no CHD was not statistically significant. There was no difference in mortality between the groups but EPA did reduce unstable angina and nonfatal coronary events. Department pilots information prescriptions The Department of Health has announced 20 sites to pilot information prescriptions prior to a nationwide roll-out in 2008. The prescriptions will guide people with long-term conditions such as diabetes and cancer to sources of support and information about their condition. The Department hopes the project will increase patients' understanding of their discussions with health professionals, empower them to locate the information they need, and provide long-term support. NPSA guidelines for safer prescribing The National Patient Safety Agency (www.npsa.nhs.uk) has published five guidelines to improve medication safety in the NHS. Targeting ,high-risk issues', the guidance covers anticoagulant prescribing, liquid medicines for oral or enteral administration, injectable medicines, epidural injections and infusions, and paediatric intravenous infusions. The implementation of each guide is supported by additional tools and resources. Better adherence not matched to outcomes A systematic review has found that interventions can increase adherence to prescribed medication but there is no evidence that clinical outcomes also improve (Arch Intern Med 2007;167:540-9). The review of 37 trials identified 20 reporting increased adherence. The most effective interventions were behavioural changes to reduce dose demands and those involving monitoring and feedback. Improvements in clinical outcomes were variable and did not correspond to changes in adherence. Antidepressant plus mood stabiliser no better US investigators have found that combining a mood stabiliser with an antidepressant is no more effective than a mood stabiliser alone in preventing mood changes (N Engl J Med 2007; published online 28 March, doi.10.1056/NEJMoa064135). The study found durable recovery occurred in 23.5 per cent of patients treated with a mood stabiliser and adjunctive antidepressant therapy for six months compared with 27.3 per cent of those taking a mood stabiliser plus placebo. [source] PRO: Should Aspirin Be Used in All Women Older Than 65 Years to Prevent Stroke?PREVENTIVE CARDIOLOGY, Issue 2007Judith Hsia MD A number of studies have reported that aspirin is beneficial in the prevention of cardiovascular disease. A meta-analysis of data from 3 studies of the cardioprotective effect of aspirin in women has reported that use of aspirin reduces the risk of coronary events mainly by reducing the risk of ischemic stroke. Results of the Women's Health Study showed that although there is a risk of bleeding events with aspirin use, overall this risk is outweighed by the number of strokes prevented. [source] Clinical Burden of Screening Asymptomatic Patients for Coronary Artery Disease Prior to Liver TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2009D. Filì The aim of this study is to assess the clinical burden of silent coronary artery disease (CAD) in cirrhotic candidates for liver transplantation (LT), and to evaluate the usefulness of a CAD screening approach. Between July 1999 and January 2006, we evaluated 627 LT candidates. All of them underwent a detailed clinical history. Sixteen had a previous diagnosis of CAD or symptoms suggestive (2.5%). The remaining 611 underwent further tests according to a predefined protocol, including EKG, echocardiogram and, on the basis of CAD risk factors, heart stress tests. Selective coronary angiography (SCA) was performed in the 30 patients with positive heart stress test: in only 2 did SCA show any CAD, and in both it was subcritical disease requiring neither intervention nor contraindicating LT. The 611 screened patients continued their follow-up until study closure or death. No coronary events occurred in the study population in a mean follow-up of 32.50 months (+/, 23.67 DS). No perioperative mortality related to CAD occurred in the 233 transplanted patients. In conclusion, no prognostic advantage was achieved by following a strict CAD screening protocol, leading us to believe that the cost-effectiveness of a similar screening can be unacceptably high in our setting. [source] Influence of Genetic Variation in the C-Reactive Protein Gene on the Inflammatory Response During and After Acute Coronary IschemiaANNALS OF HUMAN GENETICS, Issue 6 2006J. Suk Danik Summary The aim of this research was to assess whether common genetic variants within the C-reactive protein gene (CRP) are related to the degree of acute rise in plasma C-reactive protein (CRP) levels following an acute coronary syndrome (ACS). While polymorphisms within CRP are associated with basal CRP levels in healthy men and women, less is known about the relationship of such genetic variants and the degree of CRP rise during and after acute ischemia. Plasma CRP is associated with increased rates of recurrent coronary events. We evaluated seven common genetic variants within CRP and assessed their relationship to the degree of rise in CRP levels immediately following an acute coronary syndrome in 1827 European American patients. Variants in the putative promoter region, ,757T > C and ,286C > T > A, were associated with the highest CRP elevations after ACS. Patients with two copies of the A allele of SNP ,286C > T > A had median CRP values of 76.6 mg/L, compared to 11.1 mg/L in patients with no copies of the rare variant (p-value <0.0001), post ACS. The lowest CRP values were found for patients with minor alleles of the exonic 1059G > C and the 3,untranslated region 1846G > A SNPs. For example, patients homozygous for the minor allele of 1059G > C had 71% lower median CRP values than those homozygous for the major allele [3.5 vs 12.0 mg/L, p < 0.0001]. These trends persisted in the chronic stable phase after ischemia had resolved, and after adjustment for infarct size by peak creatinine kinase levels and clinical status by Killip class. Assessment of CRP genetic variants identified patients with higher and lower CRP elevation after acute coronary syndrome. [source] The Predictive Value of Exercise QRS Duration Changes for Post-PTCA Coronary EventsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2003Shai Efrati Background: The sensitivity and predictive values of exercise ECG testing using ST-T criteria after percutaneous transluminal coronary angioplasty (PTCA) are low, precluding its routine use for screening for restenosis. The predictive value of QRS duration criteria during exercise testing (ET) ECG after PTCA for future coronary events has not been reported. The aim of the study was to compare QRS duration changes with ST-T criteria during ET, as a predictor of coronary events after PTCA. Methods: A prospective study of 206 consecutive patients who underwent ET at a mean of 34 ± 14 days after their first PTCA, and were the followed for a mean of 23 ± 9 months. Patients were divided by QRS duration into two groups,Q1: ischemic response (QRS duration prolongation of more than 3 ms relative to the resting duration), and Q2: normal response (QRS duration shortening or without change from resting duration). Patients were also divided by their ST-T response, S1: ischemic response, and S2: normal response. Results: During follow-up 52 patients (58%) experienced restenosis or MI, or underwent CABG,Q1: 44 (85%), Q2: 8(15%) (P < 0.0002), S1: 8 (15%), S2: 44 (85%), (P < 0.641), two patients died,Q1: 1 (1%) and Q2: 1 (1%). For QRS and ST-T, the relative risk of having at least one of the coronary events was 4.02 (CI 2.1,9.9) versus 1.13 (CI 0.8,2.9), respectively. The sensitivity for future coronary events was 85% and 52% and the specificity was 48% and 98% for the QRS and ST-T criteria, respectively. Conclusion: QRS prolongation during peak ET ECG after PTCA is a more sensitive marker than ST-T criteria for detection of patients at risk for later coronary events. [source] | ||||||||||||||||||||||||||||