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Kinds of CAD Terms modified by CAD Selected AbstractsAdaptive and Feature-Preserving Subdivision for High-Quality Tetrahedral MeshesCOMPUTER GRAPHICS FORUM, Issue 1 2010D. Burkhart I.3.5 [Computer Graphics]: Curve, surface, solid, and object representations Abstract We present an adaptive subdivision scheme for unstructured tetrahedral meshes inspired by the, -subdivision scheme for triangular meshes. Existing tetrahedral subdivision schemes do not support adaptive refinement and have traditionally been driven by the need to generate smooth three-dimensional deformations of solids. These schemes use edge bisections to subdivide tetrahedra, which generates octahedra in addition to tetrahedra. To split octahedra into tetrahedra one routinely chooses a direction for the diagonals for the subdivision step. We propose a new topology-based refinement operator that generates only tetrahedra and supports adaptive refinement. Our tetrahedral subdivision algorithm is motivated by the need to have one representation for the modeling, the simulation and the visualization and so to bridge the gap between CAD and CAE. Our subdivision algorithm design emphasizes on geometric quality of the tetrahedral meshes, local and adaptive refinement operations, and preservation of sharp geometric features on the boundary and in the interior of the physical domain. [source] A framework for quad/triangle subdivision surface fitting: Application to mechanical objectsCOMPUTER GRAPHICS FORUM, Issue 1 2007Guillaume Lavoué Abstract In this paper we present a new framework for subdivision surface approximation of three-dimensional models represented by polygonal meshes. Our approach, particularly suited for mechanical or Computer Aided Design (CAD) parts, produces a mixed quadrangle-triangle control mesh, optimized in terms of face and vertex numbers while remaining independent of the connectivity of the input mesh. Our algorithm begins with a decomposition of the object into surface patches. The main idea is to approximate the region boundaries first and then the interior data. Thus, for each patch, a first step approximates the boundaries with subdivision curves (associated with control polygons) and creates an initial subdivision surface by linking the boundary control points with respect to the lines of curvature of the target surface. Then, a second step optimizes the initial subdivision surface by iteratively moving control points and enriching regions according to the error distribution. The final control mesh defining the whole model is then created assembling every local subdivision control meshes. This control polyhedron is much more compact than the original mesh and visually represents the same shape after several subdivision steps, hence it is particularly suitable for compression and visualization tasks. Experiments conducted on several mechanical models have proven the coherency and the efficiency of our algorithm, compared with existing methods. [source] SVG Linearization and AccessibilityCOMPUTER GRAPHICS FORUM, Issue 4 2002Ivan Herman Abstract The usage of SVG (Scaleable Vector Graphics) creates new possibilities as well as new challenges for theaccessibility of Web sites. This paper presents a metadata vocabulary to describe the information content ofan SVG file geared towards accessibility. When used with a suitable tool, this metadata description can helpin generating a textual ("linear") version of the content, which can be used for users with disabilities or withnon-visual devices. Although this paper concentrates on SVG, i.e. on graphics on the Web, the metadata approach and vocabularypresented below can be applied in relation to other technologies, too. Indeed, accessibility issues have a muchwider significance, and have an effect on areas like CAD, cartography, or information visualization. Hence, theexperiences of the work presented below may also be useful for practitioners in other areas. ACM CSS: I.3.4 Graphics Utilities,Graphics Packages, I.3.6 Methodology and Techniques,Graphics datastructures and data types, Standards, K.4.2 Social Issues,Assistive technologies for persons with disabilities [source] Semi-Automatic 3D Reconstruction of Urban Areas Using Epipolar Geometry and Template MatchingCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 7 2006José Miguel Sales Dias The main challenge is to compute the relevant information,building's height and volume, roof's description, and texture,algorithmically, because it is very time consuming and thus expensive to produce it manually for large urban areas. The algorithm requires some initial calibration input and is able to compute the above-mentioned building characteristics from the stereo pair and the availability of the 2D CAD and the digital elevation model of the same area, with no knowledge of the camera pose or its intrinsic parameters. To achieve this, we have used epipolar geometry, homography computation, automatic feature extraction and we have solved the feature correspondence problem in the stereo pair, by using template matching. [source] CAD-Based Photogrammetry for Reverse Engineering of Industrial InstallationsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2003Johan W. H. Tangelder For instance, in the case of a servicing plant, such a library contains descriptions of simple components such as straight pipes, elbows, and T-junctions. A new installation is constructed by selecting and connecting the appropriate components from the library. This article demonstrates that one can use the same approach for reverse engineering by photogrammetry. In our technique, the operator interprets images and selects the appropriate CAD component from a library. By aligning the edges of the component's wire frame to the visible edges in the images, we implicitly determine the position, orientation, and shape of the real component. For a fast object reconstruction the alignment process has been split in two parts. Initially, the operator approximately aligns a component to the images. In a second step a fitting algorithm is invoked for an automatic and precise alignment. Further improvement in the efficiency of the reconstruction is obtained by imposing geometric constraints on the CAD components of adjacent object parts. [source] Spatial Information: Classification and Applications in Building DesignCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2002Tang-Hung Nguyen Physical properties of building components are usually represented in building data models by their three-dimensional geometry and topology,also called spatial information. While geometric data of building components can be manipulated and managed by a computer-aided design (CAD) interface, their spatial relations (or topological information) are conventionally represented in a manual fashion into data models. The manual data representation, however, is inherently a complex and challenging task due to the wide variety of spatial relationships. Thus, topological information should be classified and modeled in such a way that the required spatial data for a particular design task can be automatically retrieved. This paper attempts to identify and classify various topological information commonly used in building design and construction into more specific categories (e.g., adjacency, connection, containment, separation, and intersection) to support automatic deduction of the spatial information in a computer-based building design system. The paper also discusses typical applications of the topological relations to different design activities. Finally, the development of deduction algorithms and the proposed building design system are briefly described. [source] Elevated Serum Cardiac Markers Predict Coronary Artery Disease in Patients With a History of Heart Failure Who Present With Chest Pain: Insights From the i*trACS RegistryCONGESTIVE HEART FAILURE, Issue 3 2007Jonathan Glauser MD The significance of a history of heart failure (HF) in patients presenting with acute coronary syndromes and elevated cardiac markers is unclear. The authors performed an analysis of patients enrolled in the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS). Cardiac marker measurement and cardiac catheterization were performed in 1174 patients. Of these, 116 (9.9%) had heart failure (HF). Coronary artery disease (CAD) was found in 61 (52.6%) patients in the HF group and 581 (54.9%) in the group without HF. In the non-HF cohort, positive markers occurred in 306 patients, in whom 217 (70.9%) had CAD at catheterization. In the HF subset, 24 patients had positive biomarkers and 15 (62.5%) had CAD. A history of HF did not lessen the likelihood of CAD as evidenced by angiography and does not diminish the utility of cardiac markers in diagnosing acute coronary syndromes. [source] A role for the volume regulated anion channel in volume regulation in the murine CNS cell line, CADACTA PHYSIOLOGICA, Issue 2 2010V. L. Harvey Abstract Aim:, The role of the volume regulated anion channel (VRAC) in a model CNS neuronal cell line, CAD, was investigated. Methods:, Changes in cell volume following hypotonic challenges were measured using a video-imaging technique. The effect of the Cl, channel antagonists tamoxifen (10 ,m) and 4,4,-diisothiocyanatostilbene-2,2,-disulphonic acid (DIDS; 100 ,m) on regulatory volume decrease (RVD) were measured. The whole-cell voltage-clamp technique was used to characterize IClswell, the current underlying the VRAC. Results:, Using the video-imaging technique, CAD cells were found to swell and subsequently exhibit RVD when subjected to a sustained hypotonic challenge from 300 mOsmol kg,1 H2O to 210 mOsmol kg,1 H2O. In the presence of tamoxifen (10 ,m) or DIDS (100 ,m) RVD was abolished, suggesting a role for the VRAC. A hypotonic solution (230 mOsmol kg,1 H2O) evoked IClswell, an outwardly rectifying current displaying time-independent activation, which reversed upon return to isotonic conditions. The reversal potential (Erev) for IClswell was ,14.7 ± 1.4 mV, similar to the theoretical Erev for a selective Cl, conductance. IClswell was inhibited in the presence of DIDS (100 ,m) and tamoxifen (10 ,m), the DIDS inhibition being voltage dependent. Conclusions:, Osmotic swelling elicits an outwardly rectifying Cl, conductance in CAD cells. The IClswell observed in these cells is similar to that observed in other cells, and is likely to provide a pathway for the loss of Cl, which leads to water loss and RVD. As ischaemia, brain trauma, hypoxia and other brain pathologies can cause cell swelling, CAD cells represent a model cell line for the study of neuronal cell volume regulation. [source] Methods for detecting coronary disease: epidemiology and clinical managementACTA PHYSIOLOGICA, Issue 2 2002O. Faergeman ABSTRACT The epidemic of atherosclerotic disease in wealthy countries had probably begun by 1900. Although a few physicians understood how atherosclerosis/thrombosis of the coronary arteries caused angina pectoris and myocardial infarction, the medical community did not accept that relationship until the 1920s. In wealthy countries, the epidemic peaked in mid-century, and it is now advancing in poor countries and in countries becoming affluent. Two recent developments in methods for disease detection, however, will profoundly affect not only our understanding of the epidemic of atherosclerotic disease, but also our management of patients. A redefinition of the clinical diagnosis of myocardial infarction, a well-used but imperfect measure of the epidemic, was published in September 2000. Criteria employed for about 50 years have now been replaced by criteria based on sensitive biochemical markers of necrosis of as little as 1 g of myocardium, accompanied by chest discomfort or electrocardiographic (ECG) changes, or following coronary artery intervention. The new criteria, adopted by the major societies of cardiology in Europe and the United States, is likely to increase the apparent incidence and prevalence of coronary heart disease (CHD). In the beginning of the twentieth century, diagnosis of CHD required an autopsy. In the end it was carried out by angiography as well, but it could not be applied to large proportions of the population. That has now been changed by new, non-invasive methods of computer tomography (CT) and magnetic resonance imaging (MRI), and patients, however, asymptomatic, will expect treatment for a disease that physicians have detected. Coronary artery disease (CAD) will be to CHD what occult cancer is to cancer. [source] Platelet hyperactivity in clinical depression and the beneficial effect of antidepressant drug treatment: how strong is the evidence?ACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2004R. Von Känel Objective:, Platelet hyperactivity is thought to contribute to the increased coronary artery disease (CAD) risk in depression. This study reviewed the evidence for hyperactive platelets and for effects of antidepressant drug treatment on platelet ,stickiness' in clinical depression. Method:, By means of PubMed electronic library search, 34 studies in English were identified (1983,2003) and critically reviewed. Results:, In depression, flow cytometry studies allowing detection of subtle platelet activation states consistently found at least one platelet activation marker to be increased, while the bulk of platelet aggregation studies did not suggest increased platelet aggregability. Platelets seem to be more activated in depressed patients with CAD than in depressed individuals without CAD. The selective serotonin reuptake inhibitors normalized platelet hyperactivity in four studies. Conclusion:, Data on platelet activity in depression are inconclusive. To resolve this issue and its clinical implications, studies in larger sample sizes controlling for confounders of platelet functioning and prospectively designed are needed. [source] Prognostic significance of asymptomatic coronary artery disease in patients with diabetes and need for early revascularization therapyDIABETIC MEDICINE, Issue 9 2007E.-K. Choi Abstract Aims, Information on the clinical outcome of patients with diabetes with silent myocardial ischaemia is limited. We compared the clinical and angiographic characteristics, and the clinical outcomes of diabetic patients with asymptomatic or symptomatic coronary artery disease (CAD). Methods, Three hundred and ten consecutive diabetic patients with CAD were divided into two groups according to the presence of angina and followed for a mean of 5 years. Fifty-six asymptomatic patients with a positive stress test and CAD on coronary angiography were compared with 254 symptomatic patients, 167 with unstable angina and 87 with chronic stable angina. Results, Although the severity of coronary atherosclerosis was similar in asymptomatic and symptomatic patients, revascularization therapy was performed less frequently in the asymptomatic than the symptomatic patients (26.8 vs. 62.0%; P < 0.001). Asymptomatic patients experienced a similar number of major adverse cardiac events (MACEs; death, non-fatal myocardial infarction, and revascularization; 32 vs. 28%; P = 0.57), but had higher cardiac mortality than symptomatic patients (26 vs. 9%; P < 0.001). However, patients who underwent revascularization therapy at the time of CAD diagnosis in these two groups showed similar MACE and cardiac mortality (20.0 vs. 22.5%, 6.7 vs. 5.3%, respectively; all P > 0.05). Conclusions, This study suggests that diabetic patients with asymptomatic CAD have a higher cardiac mortality risk than those with symptomatic CAD, and that lack of revascularization therapy may be responsible for the poorer survival. [source] Prevalence of silent myocardial ischaemia in new-onset middle-aged Type 2 diabetic patients without other cardiovascular risk factorsDIABETIC MEDICINE, Issue 7 2006P. Fornengo Abstract Aims Coronary artery disease (CAD) is the leading cause of death in patients with Type 2 diabetes and is often asymptomatic. Silent myocardial ischaemia (SMI) is frequent in diabetic subjects and is responsible for a late diagnosis of CAD; its early detection is important. There are some data about the prevalence of SMI in Type 2 diabetic patients at high risk for cardiovascular disease, while no data are available in subjects at the onset of diabetes without other cardiovascular risk factors. Methods We screened 274 consecutive patients (mean age 64.3 ± 8.4 years, 66% male) at the time of diagnosis of Type 2 diabetes; we enrolled 111 subjects without other cardiovascular disease risk factors (dyslipidaemia, hypertension, peripheral vascular disease, retinopathy, microalbuminuria, history of heart disease) and with normal resting electrocardiogram (ECG). Participants performed a maximal ECG exercise protocol and, if positive, underwent coronary angiography. Results The ECG exercise test was positive in 19 patients (17.1%); of those 14 (13%) had angiographic coronary disease (one with three-vessel disease, three with two vessels and 10 with one vessel involved). The positive predictive value of the exercise ECG for predicting angiographic coronary disease was 73%. Conclusions The prevalence of SMI was 17% and angiographic coronary disease was found in 13% of middle-aged subjects with new-onset Type 2 diabetes without other cardiovascular risk factors. This prevalence is similar to that observed in studies of subjects with long duration diabetes who have additional cardiovascular risk factors. [source] The MTHFR C677T polymorphism confers a high risk for stroke in both homozygous and heterozygous T allele carriers with Type 2 diabetesDIABETIC MEDICINE, Issue 5 2006M. P. Hermans Abstract Objective Individuals with Type 2 diabetes are at increased risk of stroke. Plasma homocysteine (tHcy) is an independent risk factor for cardiovascular (CV) disease. The methylene,tetrahydrofolate reductase (MTHFR) gene polymorphism (thermolabile variant C677T) is associated with CV risk, partly as a result of increased Hcy, especially in homozygous subjects. Aim To relate the occurrence of the MTHFR polymorphism with stroke prevalence by examining allelic frequency and genotype distribution in 165 subjects with Type 2 diabetes studied for the presence of thermolabile C677T MTHFR mutation. Results Mean age was 67.7 years, and tHcy 18.2 µmol/l. T allele frequency was 38.5%. MTHFR genotypes were: normal (CC) 40%; heterozygous (CT) 43%; homozygous (TT) 17%. Serum levels of folic acid and B12 vitamin were within normal limits. Stroke prevalence was 14%. Sixty-four per cent of stroke-free subjects had the normal C allele vs. 46% in stroke subjects. The frequencies of genotypes (CC-CT-TT) were (%): 44-41-15 in stroke-free vs. 17-57-26 in stroke patients. Coronary (CAD) and peripheral artery disease (PAD) were common in all groups, with no differences according to genotypes. Stroke prevalence was markedly higher in genotypes CT and TT (18 and 21%) compared with CC (6%). Mean tHcy levels were higher in TT subjects. Conclusion The allelic frequency of C677T MTHFR mutation in Type 2 diabetes subjects with stroke is markedly different from that of subjects without stroke. Genotypic characteristics suggest that C677T MTHFR mutation confers a higher risk for stroke to both homozygous and heterozygous T allele carriers that cannot be ascribed solely to raised tHcy and/or lower folate status in CT subjects, nor to phenotypic expression of conventional risk factors for stroke. The impact of the MTHFR polymorphism on stroke may result from T allele-linked deleterious effects, or C allele-linked protection. Confirmatory studies are warranted, as this cohort was not randomly selected, and a type 1 error cannot be ruled out. [source] The Relation between the Color M-Mode Propagation Velocity of the Descending Aorta and Coronary and Carotid Atherosclerosis and Flow-Mediated DilatationECHOCARDIOGRAPHY, Issue 3 2010Yilmaz Gunes M.D. Background: To improve clinical outcomes, noninvasive imaging modalities have been proposed to measure and monitor atherosclerosis. Common carotid intima-media thickness (CIMT) and brachial artery flow-mediated dilatation (FMD) have correlated with coronary atherosclerosis. Recently, the color M-mode-derived propagation velocity of descending thoracic aorta (AVP) was shown to be associated with coronary artery disease (CAD). Methods: CIMT, FMD, and AVP were measured in 92 patients with CAD and 70 patients having normal coronary arteries (NCA) detected by coronary angiography. Patients with acute myocardial infarction, renal failure or hepatic failure, aneurysm of aorta, severe valvular heart disease, left ventricular ejection fraction <40%, atrial fibrillation, frequent premature beats, left bundle branch block, and inadequate echocardiographic image quality were excluded. Results: Compared to patients with normal coronary arteries, patients having CAD had significantly lower AVP (29.9 ± 8.1 vs. 47.5 ± 16.8 cm/sec, P < 0.001) and FMD (5.3 ± 1.9 vs. 11.4 ± 5.8%, P < 0.001) and higher CIMT (0.94 ± 0.05 vs. 0.83 ± 0.14 mm, P < 0.001) measurements. There were significant correlations between AVP and CIMT (r =,0.691, P < 0.001), AVP and FMD (r = 0.514, P < 0.001) and FMD and CIMT (r =,0.530, P < 0.001). Conclusions: The transthoracic echocardiographic determination of the color M-mode propagation velocity of the descending aorta is a simple practical method and correlates well with the presence of carotid and coronary atherosclerosis and brachial endothelial function. (Echocardiography 2010;27:300-305) [source] Comparison of LVEF Obtained with Single-Plane RAO Ventriculography and Echocardiography in Patients with and without Obstructive Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 6 2009Vijayasree Kudithipudi M.D. The left ventricular ejection fraction (LVEF) determined by invasive ventriculography (routine cardiac cath; LV-gram) was compared with that determined by echocardiography in 100 patients scheduled for angiography (86% had LV-gram and 2DE during same hospital admission). Seventy percent of patients had at least single-vessel obstructive coronary artery disease, defined as more than 50% stenosis. By all estimates, the LVEF was higher in patients without coronary artery disease (CAD) compared to patients with CAD. There was an excellent correlation between the LVEF by cath and echo, but this correlation was noticeably less strong in patients with CAD, especially with involvement of the left circumflex artery. (ECHOCARDIOGRAPHY, Volume 26, July 2009) [source] Prognostic Value of Exercise Stress Test and Dobutamine Stress Echo in Patients with Known Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 1 2009Francesca Innocenti M.D. Background: The aim of this study was to compare the feasibility of dobutamine stress echocardiography (DSE) and exercise stress test (EST) between patients in different age groups and to evaluate their proportional prognostic value in a population with established coronary artery disease (CAD). Methods: The study sample included 323 subjects, subdivided in group 1 (G1), comprising 246 patients aged <75 years, and group 2 (G2), with 77 subjects aged ,75 years. DSE and EST were performed before enrollment in a cardiac rehabilitation program; for prognostic assessment, end points were all-cause mortality and hard cardiac events (cardiac death or nonfatal myocardial infarction). Results: During DSE, G2 patients showed worse wall motion score index (WMSI), but the test was stopped for complications in a comparable proportion of cases (54 G1 and 19 G2 patients, P = NS). EST was inconclusive in similarly high proportion of patients in both groups (76% in G1 vs. 84% in G2, P = NS); G2 patients reached a significantly lower total workload (6 ± 1.6 METs in G1 vs. 5 ± 1.2 METs in G2, P < 0.001). At multivariate analysis, a lower peak exercise capacity (HR 0.566, CI 0.351,0.914, P = 0.020) was associated with higher mortality, while a high-dose WMSI >2 (HR 5.123, CI 1.559,16.833, P = 0.007), viability (HR 3.354, CI 1.162,9.678, P = 0.025), and nonprescription of beta-blockers (HR 0.328, CI 0.114,0.945, P = 0.039) predicted hard cardiac events. Conclusion: In patients with known CAD, EST and DSE maintain a significant prognostic role in terms of peak exercise capacity for EST and of presence of viability and an extensive wall motion abnormalities at peak DSE. [source] Transthoracic Doppler Echocardiographic Coronary Flow Imaging in Identification of Left Anterior Descending Coronary Artery Stenosis in Patients with Left Bundle Branch BlockECHOCARDIOGRAPHY, Issue 10 2008Ozer Soylu M.D. Background: Conventional noninvasive methods have well-known limitations for the detection of coronary artery disease (CAD) in patients with left bundle branch block (LBBB). However, advancements in Doppler echocardiography permit transthoracic imaging of coronary flow velocities (CFV) and measurement of coronary flow reserve (CFR). Our aim was to evaluate the diagnostic value of transthoracic CFR measurements for detection of significant left anterior descending (LAD) stenosis in patients with LBBB and compare it to that of myocardial perfusion scintigraphy (MPS). Methods: Simultaneous transthoracic CFR measurements and MPS were analyzed in 44 consecutive patients with suspected CAD and permanent LBBB. Typical diastolic predominant phasic CFV Doppler spectra of distal LAD were obtained at rest and during a two-step (0.56,0.84 mg/kg) dipyridamole infusion protocol. CFR was defined as the ratio of peak hyperemic velocities to the baseline values. A reversible perfusion defect at LAD territory was accepted as a positive scintigraphy finding for significant LAD stenosis. A coronary angiography was performed within 5 days of the CFR studies. Results: The hyperemic diastolic peak velocity (44 ± 9 cm/sec vs 62 ± 2 cm/sec; P=0.01) and diastolic CFR (1.38 ± 0.17 vs 1.93 ± 0.3; P=0.001) were significantly lower in patients with LAD stenosis compared to those without LAD stenosis. The diastolic CFR values of <1.6 yielded a sensitivity of 100% and a specificity of 94% in the identification of significant LAD stenosis. In comparison, MPS detected LAD stenosis with a sensitivity of 100% and a specificity of 29%. Conclusions: CFR measurement by transthoracic Doppler echocardiography is an accurate method that may improve noninvasive identification of LAD stenosis in patients with LBBB. [source] Stress-Induced Wall Motion Abnormalities with Low-Dose Dobutamine Infusion Indicate the Presence of Severe Disease and Vulnerable MyocardiumECHOCARDIOGRAPHY, Issue 7 2007Stephen G. Sawada M.D. Background: Patients with left ventricular (LV) systolic dysfunction due to coronary artery disease (CAD) may develop stress-induced wall motion abnormalities (SWMA) with low-dose (10 ,g/kg/min) dobutamine infusion. The clinical significance of low-dose SWMA is unknown. Objective: We investigated the clinical, hemodynamic and angiographic correlates of low-dose SWMA in patients with chronic ischemic LV systolic dysfunction. Methods: Seventy patients with chronic ischemic LV systolic dysfunction who had dobutamine stress echocardiography were studied. Clinical, hemodynamic, and angiographic parameters at rest and low-dose were compared between 38 patients (mean ejection fraction (EF) of 30 ± 8%) with low-dose SWMA and 32 patients (EF 30 ± 11%) without low-dose SWMA. Results: Multivariate analysis showed that the number of coronary territories with severe disease (stenosis ,70%)(P = 0.001, RR = 6.3) was an independent predictor of low-dose SWMA. An increasing number of collateral vessels protected patients from low-dose SWMA (P = 0.011, RR = 0.25). A higher resting heart rate was a negative predictor of low-dose SWMA (P = 0.015, RR = 0.92) but no other hemodynamic variables were predictors. In the patients with low-dose SMA, regions with low-dose SWMA were more likely to be supplied by vessels with severe disease than regions without low-dose SWMA (92% vs 58%, P < 0.001). Conclusion: In patients with ischemic LV systolic dysfunction, the extent of severe disease and a lower numbers of collaterals predict the occurrence of low-dose SWMA. Low-dose SWMA is a highly specific marker for severe disease. [source] Real Time Myocardial Contrast Echocardiography During Supine Bicycle Stress and Continuous Infusion of Contrast Agent.ECHOCARDIOGRAPHY, Issue 6 2007Cutoff Values for Myocardial Contrast Replenishment Discriminating Abnormal Myocardial Perfusion Background: Myocardial contrast echocardiography (MCE) is a new imaging modality for diagnosing coronary artery disease (CAD). Objective: The aim of our study was to evaluate feasibility of qualitative myocardial contrast replenishment (RP) assessment during supine bicycle stress MCE and find out cutoff values for such analysis, which could allow accurate detection of CAD. Methods: Forty-four consecutive patients, scheduled for coronary angiography (CA) underwent supine bicycle stress two-dimensional echocardiography (2DE). During the same session, MCE was performed at peak stress and post stress. Ultrasound contrast agent (SonoVue) was administered in continuous mode using an infusion pump (BR-INF 100, Bracco Research). Seventeen-segment model of left ventricle was used in analysis. MCE was assessed off-line in terms of myocardial contrast opacification and RP. RP was evaluated on the basis of the number of cardiac cycles required to refill the segment with contrast after its prior destruction with high-power frames. Determination of cutoff values for RP assessment was performed by means of reference intervals and receiver operating characteristic analysis. Quantitative CA was carried out using CAAS system. Results: MCE could be assessed in 42 patients. CA revealed CAD in 25 patients. Calculated cutoff values for RP-analysis (peak-stress RP >3 cardiac cycles and difference between peak stress and post stress RP >0 cardiac cycles) provided sensitive (88%) and accurate (88%) detection of CAD. Sensitivity and accuracy of 2DE were 76% and 79%, respectively. Conclusions: Qualitative RP-analysis based on the number of cardiac cycles required to refill myocardium with contrast is feasible during supine bicycle stress MCE and enables accurate detection of CAD. [source] The Relation Between Mitral Annular Calcification and Mortality in Patients Undergoing Diagnostic Coronary AngiographyECHOCARDIOGRAPHY, Issue 9 2006Howard J. Willens M.D. To determine whether the observed association between mitral annular calcification (MAC) and mortality is independent of the severity of coronary artery disease (CAD), we analyzed data from 134 male veterans (age 63 ± 10 years) followed for 5 years who had undergone diagnostic coronary angiography and transthoracic echocardiography within 6 months of each other. Echocardiograms were retrospectively reviewed for the presence of MAC. The relation of MAC to all-cause mortality was analyzed using logistic regression, and odds ratios (OR) were calculated. MAC was present in 49 (37%) subjects. Over the 5-year follow-up period, 38 (28%) patients expired. Five-year survival was 80% for subjects without MAC and 56% for subjects with MAC (P = 0.003). MAC (OR = 3.16, 95% confidence interval [CI]= 1.43,6.96, P = 0.003), ejection fraction (OR = 0.76, 95% CI = 0.59,0.97, P = 0.02), and left main CAD (OR = 2.70, 95% CI = 1.11,6.57, P = 0.02) were significantly associated with mortality in univariate analysis. After adjusting for left ventricular ejection fraction, number of obstructed coronary arteries and the presence of left main coronary artery stenosis, MAC significantly predicted death (OR = 2.48, 95% CI = 1.09,5.68, P = 0.03). Similarly, after adjusting for predictors of MAC, including ejection fraction, age, diabetes, peripheral vascular disease, and heart failure, MAC remained a significant predictor of death (OR = 2.38, 95% CI = 1.02,5.58, P = 0.04). MAC also predicted death independent of smoking status, hypertension, serum creatinine, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and C-reactive protein levels (OR = 3.98, 95% CI = 1.68,9.40, P = 0.001). MAC detected by two-dimensional echocardiography independently predicts mortality and may provide an easy-to-perform and inexpensive way to improve risk stratification. [source] Relationship Between Plasma Total Antioxidant Capacity and Thoracic Aortic Intima-Media ThicknessECHOCARDIOGRAPHY, Issue 3 2006Recep Demirbag M.D. It is known that antioxidants have an important role in the prevention of coronary artery disease (CAD). Low total antioxidant capacity (TAC) is a risk factor for ischemic heart disease. However, no data are available concerning the relationship between TAC and severity of thoracic aortic atherosclerosis. This study using multiplane transesophageal echocardiography (TEE) examined the relationship between atherosclerotic thoracic aortic intima-media thickness (TAIMT) and TAC. Twenty-nine patients (17 male, 12 female; mean age 36 ± 8 years) without a history of atherosclerotic cardiovascular disease referred for TEE were included. The patients with obesity, hypertension, diabetes, and CAD were excluded. The TAC was measured for each patient using a more recently developed method. TAIMT and grade of thoracic aortic atherosclerosis were evaluated in each patient by using TEE. Mean TAC level was 1.91 ± 0.53 mmol Trolox equiv/l. There was a negative and significant correlation between the TAC levels and TAIMT and grade of thoracic aortic atherosclerosis (r =,0.799, P < 0.001 versus r =,0.827, P < 0.001, respectively). Multiple linear regression analysis showed that TAIMT was independently associated with TAC (,=,0.734, P < 0.001). The mean values of TAC in grade I, II, and III were 2.23 ± 0.31, 1.58 ± 0.31, and 1.04 ± 0.27 mmol Trolox equiv/l, respectively (ANOVA P < 0.001). This study indicates that the TAC is an independent variable for TAIMT and it has a potential for an independent variable for atherosclerotic lesions in the major arterial locations. [source] Viable Myocardium: How Much Is Enough?ECHOCARDIOGRAPHY, Issue 1 2005A Comparison of Viability by Comparative Imaging Techniques to Assess the Quantity, Functionality of Ischemic Myocardium Left ventricular systolic dysfunction is mainly a result of coronary artery disease (CAD). Decrease in myocardial contractility results as a response to a chronic hypoperfusion state that produces a change in cardiac myocyte metabolism, resulting in a perfusion-contraction mismatch in which function is sacrificed for survival. If revascularization is performed in a timely fashion, metabolism can be restored leading to recovery of function. Through the use of noninvasive imaging modalities, assessing myocardial viability can be easily performed and will aid in selecting those patients who will benefit from revascularization. Viable myocardium can be identified by nuclear modalities that have a high sensitivity but a lower specificity, such as thallium-201 single photon emission computed tomography and positron emission tomography (PET); or by the use of dobutamine stress echocardiogram (DSE), which has a decreased sensitivity but a better specificity. A modality that is increasingly being used with an overall good sensitivity and specificity is contrast-enhanced magnetic resonance imaging. The purpose of this review is to explore the amount of myocardial viability that is relevant to pursue revascularization, since as myocardial function improves there is a decrease in morbidity and mortality from heart failure and arrhythmias. [source] Methodological Analysis of Diagnostic Dobutamine Stress Echocardiography StudiesECHOCARDIOGRAPHY, Issue 8 2004Boudewijn J. Krenning M.D. Background: Dobutamine stress echocardiography (DSE) is an accepted test for the diagnosis of coronary artery disease (CAD), despite its wide diagnostic accuracy. Aim: Which factors cause test variability of DSE for the diagnosis of CAD. Methods: In a retrospective analysis of 46 studies in 5,353 patients, the potential causes of diagnostic variability were systematically analyzed, including patient selection, definition of CAD, chest pain characteristics, confounding factors for DSE (left ventricular hypertrophy, left bundle branch block, female gender), work-up bias (present when patient's chance to undergo coronary angiography is influenced by the result of DSE), review bias (present when DSE is interpreted in relation to CAG), DSE protocol and definition of a positive DSE. Results: Diagnostic variability was related to definition of a positive test, but not related to the definition of CAD or DSE protocol. However, only three of eight methodological standards for research design found general compliance. Differences in the selection of the study population (quality of echocardiographic window, angina pectoris), handling of confounding factors and analysis of disease in individual coronary arteries were observed. Lack of data on analysis of relevant chest pain syndromes and handling of nondiagnostic test results hampered further evaluation of these standards. Conclusion: Methodological problems may explain the wide range in diagnostic variability of DSE. An improvement of clinical relevance of DSE testing is possible by stronger adherence to common and new methodological standards. [source] Design of an Ultrasound Contrast Agent for Myocardial PerfusionECHOCARDIOGRAPHY, Issue 2000Michel Schneider Ph.D. Myocardial contrast echography (MCE) has been a major research objective in cardiovascular ultrasound for almost two decades. The design of a contrast agent fulfilling the needs of MCE requires taking into consideration a number of points: a basic decision has to be made whether a deposit agent or a free-flowing agent would be more appropriate and whether an agent active at low/medium mechanical index (MI) is preferable to an agent active only at high MI; only a small percentage of the cardiac output enters the coronary microcirculation, which means that highly sensitive bubble detection methods, such as harmonic imaging or pulse inversion, are needed; the low velocity of blood in the microcirculation that leads to extensive bubble destruction during imaging means that intermittent imaging and/or an agent active at low MI is (are) required; the duration of the contrast effect must be sufficient to allow a complete examination and is affected by the rate of contrast administration; the performance of the contrast agent should not be equipment-dependent. The ultimate goal in MCE is to be able to quantify blood flow in the various segments to determine if adequate oxygenation is achieved. Ultrasound-mediated bubble destruction followed by the measurement of bubble replenishment kinetics opens new perspectives for quantification. SonoVue is a free-flowing ultrasound contrast agent made of sulphur hexafluoride microbubbles stabilized by a highly elastic phospholipid monolayer. SonoVue is able to produce myocardial opacification at a wide range of acoustic pressures and in particular at Mis as low as 0.1. Its performance is not equipment-dependent. Good results for myocardial opacification have been observed in all animal species tested (dogs, minipigs, rabbits), using continuous as well as intermittent imaging. Trials are in progress to demonstrate the clinical utility of SonoVue for rest and stress perfusion studies, in particular for the diagnosis of CAD, the detection of myocardial infarction, the assessment of the success of interventions and myocardial viability, and the detection of hibernating myocardium. [source] Diagnostic and Prognostic Use of Stress Echocardiography in Stable PatientsECHOCARDIOGRAPHY, Issue 5 2000Steven C. Smart M.D. Stress echocardiography is an effective diagnostic and prognostic technique in stable patients with known or suspected coronary artery disease (CAD), myocardial infarction, or chronic left ventricular dysfunction and those undergoing noncardiac surgery. Stress echocardiography is sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events regardless of the clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Stress echocardiography provides incremental prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable to that from radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for one-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD. [source] Role of Dobutamine Stress Echocardiography for Preoperative Cardiac Risk Assessment Before Major Vascular Surgery: A Diagnostic Tool Comes of AgeECHOCARDIOGRAPHY, Issue 1 2000DON POLDERMANS M.D. Background: Cardiac complications are a major cause for perioperative mortality and morbidity Also, the presence and severity of underlying coronary artery disease (CAD) determine long-ten prognosis after successful surgery. Aim: This overview evaluates the additional value ofdobutamir, stress echocardiography (DSE) to common clinical cardiac risk factors and other noninvasii cardiac imaging modalities for perioperative and late cardiac prognosis. Results: DSE provides tl attending physician with preoperative prognostic information for perioperative and long-ten prognosis for cardiac events. It also enables the selection of high risk patients for evaluation i cardiac risk reduction therapies. Conclusions: DSE is a useful tool for preoperative cardiac ris evaluation in addition to common clinical cardiac risk factors. (ECHOCARDIOGRAPHY, Vo ume 17, January 2000) [source] The Impact of Race on the Acute Management of Chest PainACADEMIC EMERGENCY MEDICINE, Issue 11 2003Arvind Venkat MD Abstract Objectives: African Americans with acute coronary syndromes receive cardiac catheterization less frequently than whites. The objective was to determine if such disparities extend to acute evaluation and noninterventional treatment. Methods: Data on adults with chest pain (N= 7,935) presenting to eight emergency departments (EDs) were evaluated from the Internet Tracking Registry of Acute Coronary Syndromes. Groups were selected from final ED diagnosis: 1) acute myocardial infarction (AMI), n= 400; 2) unstable angina/non,ST-elevation myocardial infarction (UA/NSTEMI), n= 1,153; and 3) nonacute coronary syndrome chest pain (non-ACS CP), n= 6,382. American College of Cardiology/American Heart Association guidelines for AMI and UA/NSTEMI were used to evaluate racial disparities with logistic regression models. Odds ratios (ORs) were adjusted for age, gender, guideline publication, and insurance status. Non-ACS CP patients were assessed by comparing electrocardiographic (ECG)/laboratory evaluation, medical treatment, admission rates, and invasive and noninvasive testing for coronary artery disease (CAD). Results: African Americans with UA/NSTEMI received glycoprotein IIb/IIIa receptor inhibitors less often than whites (OR, 0.41; 95% CI = 0.19 to 0.91). African Americans with non-ACS CP underwent ECG/laboratory evaluation, medical treatment, and invasive and noninvasive testing for CAD less often than whites (p < 0.05). Other nonwhites with non-ACS CP were admitted and received invasive testing for CAD less often than whites (p < 0.01). African Americans and other nonwhites with AMI underwent catheterization less frequently than whites (OR, 0.45; 95% CI = 0.29 to 0.71 and OR, 0.40; 95% CI = 0.17 to 0.92, respectively). A similar disparity in catheterization was noted in UA/NSTEMI therapy (OR, 0.53; 95% CI = 0.40 to 0.68 and OR, 0.68; 95% CI = 0.47 to 0.99). Conclusions: Racial disparities in acute chest pain management extend beyond cardiac catheterization. Poor compliance with recommended treatments for ACS may be an explanation. [source] Effect of magnitude and direction of force on laryngeal abduction: Implications for the nerve-muscle pedicle graft techniqueEQUINE VETERINARY JOURNAL, Issue 4 2009P. CRAMP Summary Reasons for performing study: The nerve-muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Hypothesis: The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods: Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead-weight force generator applied a force of 0,14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70° angles. The rima glottis was photographed digitally 1 min after each force had been applied. Distances between biomarkers (Lines 1,4) and right to left angle quotient (RLQ) were used to assess the degree of left arytenoid abduction. Results: Increasing force from 0,14.7 N progressively and significantly increased the length of all lines and RLQ, indicating abduction. Furthermore, there was a significant interaction between force and angles. Applying forces of 7.84 N or greater (Lines 2,4 and RLQ) or 11.76 N or greater (Line 1) at angles 0, 10, 20 and 30° resulted in significantly greater abduction than applying the same forces at 40, 50, 60 and 70°. Angles of 0,30° correspond with the direction of pull exerted by the lateral compartment of the CAD muscle. Conclusion: In RLN, nerve-muscle pedicle grafts should be placed preferentially in the lateral rather than in the medial compartment of the CAD muscle. Potential relevance: The information presented can be used to assist surgeons in the planning and application of the nerve-muscle pedicle graft procedure. [source] Effect of atorvastatin on microRNA 221,/,222 expression in endothelial progenitor cells obtained from patients with coronary artery diseaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2009Y. Minami Abstract Background, Endothelial progenitor cells (EPCs) play an important role in the maintenance of vascular integrity. Lipid lowering therapy (LLT) with statins may contribute to biologically relevant activities including the proliferation of endothelial cells. The physiological role of microRNA (miR)-221/222, a newly discovered class of small RNA, is closely linked to the proliferation of endothelial cells. We therefore investigated whether LLT with statins might affect miR-221/222 expression in EPCs obtained from patients with coronary artery disease (CAD). Materials and methods, This study included 44 patients with stable CAD and 22 subjects without CAD (non-CAD). Patients with CAD were randomized to 12 months of LLT with atorvastatin (10 mg day,1) or pravastatin (10 mg day,1). EPCs were obtained from peripheral blood at baseline and after 12 months of statin therapy. Levels of miR-221/222 in EPCs were measured by real-time RT-PCR. Results, Levels of miR-221/222 were significantly higher in the CAD group than in the non-CAD group (P < 0·01). Levels of miR-221/222 were weakly negatively correlated with EPC number in the CAD group. After 12 months of therapy, changes in lipid profiles were greater in the atorvastatin group than in the pravastatin group. LLT with atorvastatin markedly increased EPC numbers and decreased miR-221/222 levels (all P < 0·05), whereas LLT with pravastatin did not change EPC numbers or miR-221/222 levels. Conclusions, This study demonstrates that LLT with atorvastatin increases EPC numbers and decreases miR-221/222 levels in patients with CAD, possibly contributing to the beneficial effects of LLT with atorvastatin in this disorder. [source] Glutathione, vitamin E and oxidative stress in coronary artery disease: relevance of age and genderEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2009V. Cavalca Abstract Background, Observational studies suggest that low levels of antioxidants are associated with high risk for coronary artery disease (CAD). We investigated whether the biomarkers of oxidative balance undergo the same modifications in all CAD patient groups, regardless of gender and age. Materials and methods, One hundred sixty-eight CAD patients and 107 healthy controls were assayed for plasma levels of reduced glutathione (GSH), ,- and ,-tocopherol (,- and ,-T) as endogenous antioxidants. A damage score (DS), representative of oxidative stress status, was calculated. ancova models were used to test the association between antioxidants, DS and CAD and its modulation by age and gender. Results, The DS was higher in CAD than in controls. GSH levels, were lower in CAD patients (mean ± SEM: 57·61 ± 1·87 ,mol 10 g,1 haemoglobin vs. 68·55 ± 2·23 in controls, P < 0·0006) in males and in older subjects. Levels of other antioxidants exhibited a complex pattern. Overall, no difference was found in ,- and ,-T contents between CAD and controls, but lower ,-T values were observed in CAD females. A significant interaction between CAD status and gender was observed (P = 0·003). Conclusions, Our study shows that the involvement of antioxidants in CAD is related to patients' characteristics. These findings may be relevant in planning antioxidant therapies. [source] | |||||||||||||||||||||||||||||||||||||||||||