Home About us Contact
|
Home About us Contact | ||
|
|
||
K Antagonists (k + antagonist)
Kinds of K Antagonists Selected AbstractsWhich parameters differ in very old patients with chronic atrial fibrillation treated by anticoagulant or aspirin?FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 5 2008Antithrombotic treatment of atrial fibrillation in the elderly Abstract The objective was to determine the main parameters taken into account for the decision of antithrombotic treatment of atrial fibrillation (AF) by vitamin K antagonist or aspirin. This was a prospective clinical study of four clinical services of geriatric medicine. Two hundred and nine inpatients, 84.7 ± 7 years (women 60.8%), with chronic AF were included. The patients were distributed into two groups (anticoagulant or aspirin) according to medical decision. All the decision criteria for treatment were recorded: cardiopathy, conditions of life, clinical examination (nutrition and autonomy, mini-mental state examination (MMSE), walking evaluation, comorbidity), subjective evaluation of risk of falls and glomerular filtration rate. The thromboembolic risk and the bleeding risk, evaluated subjectively for each patient, were compared with two scores of thrombo-embolic risk and bleeding risk. The evolution of the patients was recorded after 3 months. Student's t -test and chi-squared tests were used for statistical analysis. One hundred and two patients (48.8%) received anticoagulant and 107 patients received aspirin. Patients in the aspirin group were significantly older (86.5 ± 6.5 vs. 82.9 ± 7.1 years), with more frequent social isolation, higher systolic blood pressure, and had more important subjective bleeding risk and risk of falls. Patients in the anticoagulant group had significantly more valvulopathies and a more important subjective thromboembolic risk. Thrombo-phlebitis antecedents, dementia, denutrition and walking alterations were only slightly more frequent in patients in the aspirin group. Physicians underestimated thromboembolic risk (one-third of patients) and they overestimated bleeding risk (half of the patients). After 3 months, the two groups did not significantly differ for death, bleeding or ischaemic events. In common practice, the decision of antithrombotic treatment for AF should take into account not only cardiovascular but also geriatric criteria. [source] Can oral vitamin K before elective surgery substitute for preoperative heparin bridging in patients on vitamin K antagonists?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2010A. STEIB See also Douketis JD, Spyropoulos AC. Vitamin K to reverse the anticoagulant effect of vitamin K antagonists: can you teach an old dog new tricks? This issue, pp 496,8. Summary.,Background: After a vitamin K antagonist (VKA) overdose, 1,2 mg of oral vitamin K can lower the International Normalized Ratio (INR) to the therapeutic range. Objective: To establish whether oral vitamin K can substitute for heparin bridging and decrease the INR to , 1.5 before elective surgery. Methods: Patients on long-term VKAs were randomized either to heparin bridging after the last VKA dose on day , 5 before surgery (group H) or to VKA treatment until day , 2, followed by 1 mg of oral vitamin K on the day before surgery (group K). Blood clotting variables were assessed on days ,5/,2, 1 and 0, and postoperatively. If the target INR was not achieved 2 h before incision, surgery was deferred or performed after injection of prothrombin complex concentrate (PCC). Results: In 30 of 94 included patients, baseline INR was outside the chosen range (18, INR < 2; 12, INR > 3.5), leaving 34 eligible patients in group H and 30 in group K. The groups were balanced in terms of body mass index, VKA treatment duration and indication, scheduled surgery, preoperative and postoperative hemoglobin, and blood loss. The INR was significantly higher in group K on days , 1 and 0 than in group H. An INR , 1.5 was not achieved in 20 group K patients (66%). Surgery was postponed or performed after PCC injection in 12 of these 20 patients. Conclusions: Oral vitamin K (1 mg) cannot substitute for heparin bridging before surgery. In addition, one-third of patients on VKAs were exposed to a risk of bleeding (overdose) or thrombosis (underdose), thus highlighting the need for new oral anticoagulants. [source] Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)AUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2002DJ RUNCIMAN A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. [source] Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)AUSTRALIAN VETERINARY JOURNAL, Issue 1 2002DJ RUNCIMAN A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. [source] Contemporary management of pulmonary embolism: the answers to ten questionsJOURNAL OF INTERNAL MEDICINE, Issue 3 2010H. Bounameaux Abstract., Bounameaux H (Division of Angiology and Hemostasis, Department of Internal Medicine, University Hospitals of Geneva and Faculty of Medicine, Geneva, Switzerland). Contemporary management of pulmonary embolism: the answers to ten questions (Review). J Intern Med 2010; 268: 218,231. Pulmonary embolism (PE) cannot be diagnosed solely on a clinical basis, because of the lack of sensitivity and specificity of clinical signs and symptoms. Pulmonary angiography is invasive and resource demanding. Because the prevalence of PE is relatively low (20% or less) amongst individuals who are clinically suspected of having the disease, submitting all of them to imaging (multi-detector CT angiography or ventilation/perfusion lung scintigraphy) would not be cost-effective. Therefore, diagnostic algorithms have been developed that include clinical probability assessment and D-dimer measurement to select the patients who require noninvasive imaging. Once the diagnosis is suspected or confirmed, therapy must be started to avoid potentially fatal recurrence. Treatment starts for an initial 3-month period with a 5-day course of parenteral unfractionated or low-molecular-weight heparin or fondaparinux overlapping with and followed by oral vitamin K antagonists monitored to maintain an international normalized ratio of 2,3. This initial period of 3 months may then be followed by a long-term secondary prevention period in patients who experience an idiopathic thromboembolic event and are at low risk of bleeding. New oral anticoagulants that do require patient monitoring and might exhibit a more favourable benefit,risk balance are currently under extensive clinical testing and might change the situation in the near future. A critical appraisal of the contemporary management of suspected PE is given in this overview with the discussion of 10 practical questions. [source] Vitamin K to reverse the anticoagulant effect of vitamin K antagonists: can you teach an old dog new tricks?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2010J. D. DOUKETIS To cite this article: Douketis JD, Spyropoulos AC. Vitamin K to reverse the anticoagulant effect of vitamin K antagonists: can you teach an old dog new tricks? J Thromb Haemost 2010; 8: 496,8. See also Steib A, Barre J, Mertes M, Morel MH, Nathan N, Ozier Y, Treger M, Samama CM. Can oral vitamin K before elective surgery substitute for preoperative heparin bridging in patients on vitamin K antagonists? This issue, pp 499,503. [source] Can oral vitamin K before elective surgery substitute for preoperative heparin bridging in patients on vitamin K antagonists?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2010A. STEIB See also Douketis JD, Spyropoulos AC. Vitamin K to reverse the anticoagulant effect of vitamin K antagonists: can you teach an old dog new tricks? This issue, pp 496,8. Summary.,Background: After a vitamin K antagonist (VKA) overdose, 1,2 mg of oral vitamin K can lower the International Normalized Ratio (INR) to the therapeutic range. Objective: To establish whether oral vitamin K can substitute for heparin bridging and decrease the INR to , 1.5 before elective surgery. Methods: Patients on long-term VKAs were randomized either to heparin bridging after the last VKA dose on day , 5 before surgery (group H) or to VKA treatment until day , 2, followed by 1 mg of oral vitamin K on the day before surgery (group K). Blood clotting variables were assessed on days ,5/,2, 1 and 0, and postoperatively. If the target INR was not achieved 2 h before incision, surgery was deferred or performed after injection of prothrombin complex concentrate (PCC). Results: In 30 of 94 included patients, baseline INR was outside the chosen range (18, INR < 2; 12, INR > 3.5), leaving 34 eligible patients in group H and 30 in group K. The groups were balanced in terms of body mass index, VKA treatment duration and indication, scheduled surgery, preoperative and postoperative hemoglobin, and blood loss. The INR was significantly higher in group K on days , 1 and 0 than in group H. An INR , 1.5 was not achieved in 20 group K patients (66%). Surgery was postponed or performed after PCC injection in 12 of these 20 patients. Conclusions: Oral vitamin K (1 mg) cannot substitute for heparin bridging before surgery. In addition, one-third of patients on VKAs were exposed to a risk of bleeding (overdose) or thrombosis (underdose), thus highlighting the need for new oral anticoagulants. [source] More on: vitamin K antagonists and cancerJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2008G. AGNELLI [source] More on: vitamin K antagonists and cancerJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2008S. SCHULMAN [source] Factor Xa or thrombin: is factor Xa a better target?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2007J. ANSELL Summary., Existing vitamin K antagonists (VKAs) have drawbacks that limit their effectiveness, safety, and overall frequency of use. Oral anticoagulants in development with targeted action against individual coagulation factors, specifically direct factor (F) Xa and IIa inhibitors, appear to have pharmacokinetic and pharmacodynamic properties that overcome the limitations of the VKAs. Based on the theory of how coagulation factors interact, on the results of in vitro studies, and on clinical outcomes, there is accumulating evidence that FXa may represent a better target for inhibition than FIIa. This is based on an understanding of the amplified nature of coagulation factor interactions and fibrin formation, the need for smaller doses of an anticoagulant to block coagulation progression earlier in the sequence of reactions, the evidence for incomplete suppression of thrombin generation with direct thrombin inhibitors, evidence for rebound hypercoagulability with thrombin inhibitors, and clinical results with the indirect, parenteral, FXa inhibitor (fondaparinux), as well as early phase II results of new oral Xa and IIa inhibitors compared with enoxaparin. The latter studies, although not comparative, provide some evidence for the effectiveness and safety of Xa inhibitors at a range of doses not seen with the direct IIa inhibitors. [source] Use of preventive measures for air travel-related venous thrombosis in professionals who attend medical conferencesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2006S. KUIPERS Summary.,Background:,Lack of guidelines for prevention of air travel-related venous thrombosis may lead to excessive use of potentially dangerous precautions. Objectives:,To assess the use of preventive measures for air travel-related thrombosis in professionals employed in the field of thrombosis and hemostasis and in other fields. Methods:,A survey amongst delegates of the XXth ISTH Congress, the 15th ISDB Congress and the 13th Cochrane Colloquium, which all took place in Australia 2005. Results:,Two thousand and eighty-nine questionnaires were completed (response 53%). Overall, 80% of the respondents had used preventive measures. Low-molecular-weight heparin and vitamin K antagonists were mostly used by ISTH delegates (10% vs. 1% at the other conferences). Medical doctors used more pharmacological prophylaxis (31%) than research fellows (11%) and non-clinical scientists (22%). Dutch (64%) and Asian respondents (67%) least used any prevention, whereas Israeli used most (94%). Subjects with risk factors for thrombosis more often used prophylaxis (90%) than those without (77%). In a multivariate analysis, conference, nationality, age, presence of risk factors and profession were determinants of prophylaxis use. Conclusion:,Major differences in the use of prophylactic measures for air travel-related thrombosis stress the need for studies of interventions and clear guidelines on prevention of air travel-related venous thrombosis. [source] Early detection of patients with a poor response to vitamin K antagonists: the clinical impact of individual time within target range in patients with heart diseaseJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2006N. J. G. M. VEEGER No abstract is available for this article. [source] Post-thrombotic syndrome, recurrence, and death 10 years after the first episode of venous thromboembolism treated with warfarin for 6 weeks or 6 monthsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2006S. SCHULMAN Summary.,Background: The influence of the duration of anticoagulant therapy after venous thromboembolism (VTE) on the long-term morbidity and mortality is unclear. Aim: To investigate the long-term sequelae of VTE in patients randomized to different duration of secondary prophylaxis. Methods: In a multicenter trial comparing secondary prophylaxis with vitamin K antagonists for 6 weeks or 6 months, we extended the originally planned 2 years follow-up to 10 years. The patients had annual visits and at the last visit clinical assessment of the post-thrombotic syndrome (PTS) was performed. Recurrent thromboembolism was adjudicated by a radiologist, blinded to treatment allocation. Causes of death were obtained from the Swedish Death Registry. Results: Of the 897 patients randomized, 545 could be evaluated at the 10 years follow-up. The probability of developing severe PTS was 6% and any sign of PTS was seen in 56.3% of the evaluated patients. In multivariate analysis, old age and signs of impaired circulation at discharge from the hospital were independent risk factors at baseline for development of PTS after 10 years. Recurrent thromboembolism occurred in 29.1% of the patients with a higher rate among males, older patients, those with permanent triggering risk factor , especially with venous insufficiency at baseline , signs of impaired venous circulation at discharge, proximal deep vein thrombosis, or pulmonary embolism. Death occurred in 28.5%, which was a higher mortality than expected with a standardized incidence ratio (SIR) of 1.43 (95% CI 1.28,1.58), mainly because of a higher mortality than expected from cancer (SIR 1.83; 95% CI 1.44,2.23) or from myocardial infarction or stroke (SIR 1.28; 95% CI 1.00,1.56). The duration of anticoagulation did not have a statistically significant effect on any of the long-term outcomes. Conclusion: The morbidity and mortality during 10 years after the first episode of VTE is high and not reduced by extension of secondary prophylaxis from 6 weeks to 6 months. A strategy to reduce recurrence of VTE as well as mortality from arterial disease is needed. [source] Non-fatal major bleeding during treatment with vitamin K antagonists: influence of soluble thrombomodulin and mutations in the propeptide of coagulation factor IXJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2004J. F. Van Der Heijden Summary., Background and objectives : The key complication of treatment with vitamin K antagonists (VKAs) is bleeding. The major determinant of VKA-induced bleeding is the intensity of anticoagulation. Individual patient characteristics may also influence bleeding risk. In addition, soluble thrombomodulin (s-TM) levels and mutations in the propeptide of factor (F)IX are important candidate risk factors in this respect. Patients and methods : A matched case,control study was designed to search for risk factors that predict bleeding during VKA treatment. We selected cases that had experienced major bleeding during treatment with VKA and matched controls without bleeding complications from the databases of two Thrombosis Services. The controls were matched for indication of treatment, age, gender, type of anticoagulant used and whether or not treatment with VKA was stopped. DNA and plasma were stored of all cases and controls. Results and conclusions : In total 110 patients and 220 controls consented to participate. The results indicate that s-TM levels, measured by ELISA, may be a risk indicator for bleeding [crude odds ratio 3.25 for the highest quartile vs. the lowest quartile (95% confidence interval 1.40, 7.51)]. Three novel mutations, determined by direct sequencing, in the gene portion encoding the propeptide of FIX were identified that do not seem to play an important role in bleeding risk during treatment with VKAs. [source] Vitamin K antagonists and cancer: reply to rebuttalJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2 2004M. R. Taliani No abstract is available for this article. [source] Individualized duration of oral anticoagulant therapy for deep vein thrombosis based on a decision modelJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2003R. Vink Summary.,Background:,The optimal duration of oral anticoagulant therapy for patients with a first episode of deep vein thrombosis (DVT) is still a matter of debate. However, according to the ACCP consensus strategy a limited stratification in treatment duration is advocated, i.e. 3 months for patients with a transient risk factor and 1 year or longer for patients with recurrent disease or a consistent risk factor such as thrombophilia or cancer. This consensus strategy is founded on the mean optimal duration of therapy obtained in large cohorts of patients and is mainly based on the risk of recurrent venous thromboembolism (VTE), with only minimal consideration for the patient's bleeding risk. Objective:,The aim of this study is to optimize the anticoagulant treatment strategy with vitamin K antagonists for the individual patient with DVT. Methods:,Based on an extensive literature study, a mathematical model was constructed to balance the risk of recurrent VTE against the risk of major hemorrhagic complications. The following parameters are incorporated in the model: baseline estimates and risk factors for recurrent VTE and bleeding, clinical course of DVT, and efficacy of treatment with vitamin K antagonists. With the use of these parameters, the risk for a recurrent VTE and a bleeding episode can be calculated for the individual patient. The optimal duration of anticoagulant therapy can be defined as the timepoint at which the benefit of treatment (prevention of VTE) is counterbalanced by its risk (bleeding). Results/conclusions:,How long a patient should receive anticoagulant treatment is a matter of balancing the benefits and risks of treatment. The model shows that the optimal treatment duration varies greatly from patient to patient according to the patient's unique bleeding and recurrence risk. [source] Prevention and treatment of bleeding complications in patients receiving vitamin K antagonists, Part 1: Prevention,AMERICAN JOURNAL OF HEMATOLOGY, Issue 9 2009David Garcia First page of article [source] Prevention and treatment of bleeding complications in patients receiving vitamin K antagonists, part 2: Treatment,AMERICAN JOURNAL OF HEMATOLOGY, Issue 9 2009Walter Ageno First page of article [source] Point-of-care reversal treatment in phenprocoumon-related intracerebral hemorrhageANNALS OF NEUROLOGY, Issue 6 2010Timolaos Rizos MD Objective Rapid reversal of the anticoagulatory effect of vitamin K antagonists represents the primary emergency treatment for oral anticoagulant-related intracerebral hemorrhage (OAC-ICH). Predicting the amount of prothrombin complex concentrate (PCC) needed to reverse OAC in individual patients is difficult, and repeated international normalized ratio (INR) measurements in central laboratories (CLs) are time-consuming. Accuracy and effectiveness of point-of-care INR coagulometers (POCs) for INR reversal in OAC-ICH have not been evaluated. Methods In phase 1, the agreement of emergency POC and CL INR measurements was determined. In phase 2, stepwise OAC reversal was performed with PCC using a predetermined dosing schedule. Concordance of POC and CL INR measurements during reversal and time gain due to POC were determined. Results In phase 1 (n = 165), Bland-Altman analysis showed close agreement between POCs and CLs (mean INR deviation 0.04). In phase 2 (n = 26), POCs caused a median initial net time gain of 24 minutes for the start of treatment with PCC. Median time for POC-documented complete OAC reversal was 28 minutes, compared with 120 minutes for CLs. Bland-Altman analysis between POCs and CLs revealed a mean INR deviation of 0.13 during stepwise PCC administration. POCs tended to slightly overestimate the INR, especially at higher INR levels. Remarkably, POC-guided reversal led to a median reduction of 30.5% of PCC dose compared with the a priori dose calculation. Hematomas enlarged in 20% of patients. Interpretation POC INR monitoring is a fast, effective, and economic means of PCC dose-titration in OAC-ICH. Larger studies examining the clinical efficacy of this procedure are warranted. ANN NEUROL 2010;67:788,793 [source] | ||||||||||