Thromb Haemostasis
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Multicenter Study
Further validation and simplification of the Wells clinical decision rule in pulmonary embolism.
The Wells rule is a widely applied clinical decision rule in the diagnostic work-up of patients with suspected pulmonary embolism (PE). The objective of this study was to replicate, validate and possibly simplify this rule. We used data collected in 3,306 consecutive patients with clinically suspected PE to recalculate the odds ratios for the variables in the rule, to calculate the proportion of patients with PE in the probability categories, the area under the ROC curve and the incidence of venous thromboembolism during follow-up. ⋯ The venous thromboembolism incidence at three months in the group of patients with a Wells score < or = 4 and a normal D-dimer was 0.5%, versus 0.3% with a modified rule and 0.5% with a simplified rule. The proportion of patients safely excluded for PE was 32%, versus 31% and 30%, respectively. This study further validates the diagnostic utility of the Wells rule and indicates that the scoring system can be simplified to one point for each variable.
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Clinical Trial
Increased thrombin generation and fibrinogen level after therapeutic plasma transfusion: relation to bleeding.
In a clinical setting, fresh frozen plasma (FFP) is transfused to diluted patients with complicated surgery or trauma, as guided by prolonged conventional coagulation times or low fibrinogen levels. However, the limited sensitivity of these coagulation tests may restrict their use in measuring the effect of transfusion and hence predicting the risk of perioperative bleeding. We used the more sensitive, calibrated automated thrombogram (CAT) method to evaluate the result of therapeutic FFP transfusion to 51 patients with dilutional coagulopathy. ⋯ Plasmas from 15 of the 19 patients with ongoing bleeding were markedly low in either thrombin generation or fibrinogen level. We conclude that the thrombin generation method detects improved haemostatic activity after plasma transfusion. Furthermore, the data suggest that thrombin generation and fibrinogen are independent determinants of the risk of perioperative bleeding in this patient group.
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Randomized Controlled Trial Multicenter Study
Functional impact of high clopidogrel maintenance dosing in patients undergoing elective percutaneous coronary interventions. Results of a randomized study.
The currently recommended maintenance dose of clopidogrel is often associated with inadequate platelet inhibition, suggesting the need for a higher dose. The aim of this pilot study was to assess the functional impact of a high (150 mg/day) maintenance dose of clopidogrel in patients undergoing elective percutaneous coronary intervention (PCI). This is a prospective, randomized, platelet function study which was performed in elective PCI patients assigned to treatment with either a 75 mg (n = 20) or 150 mg (n = 20) daily maintenance dose of clopidogrel for 30 days; afterwards, all patients resumed standard dosing. ⋯ Parallel findings were observed following 5 microM ADP stimuli for all assessments. A broad variability in clopidogrel-induced antiplatelet effects was observed irrespective of dosing. In conclusion, a 150 mg/day maintenance dose regimen of clopidogrel is associated with reduced platelet reactivity and enhanced platelet inhibition compared to that achieved with the currently recommended 75 mg/day in patients undergoing elective PCI.
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We sought to assess the effect of clopidogrel on in-hospital events in unselected patients with acute ST elevation myocardial infarction (STEMI). In a retrospective analysis of consecutive patients enrolled in the Acute Coronary Syndromes (ACOS) registry with acute STEMI we compared outcomes of either adjunctive therapy with aspirin alone or aspirin plus clopidogrel within 24 hours after admission. A total of 7,559 patients were included in this analysis, of whom 3,541 were treated with aspirin alone, and 4,018 with dual antiplatelet therapy. ⋯ There was a significant increase in major bleeding complications with clopidogrel (7.1% vs. 3.4%, p<0.001). In clinical practice early adjunctive therapy with clopidogrel in addition to aspirin in patients with STEMI is associated with a significant reduction of in-hospital MACCE regardless of the initial reperfusion strategy. This advantage was associated with an increase in major bleeding complications.
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Acetylsalicylic acid (ASA) and the thienopyridine clopidogrel are established anti-platelet drugs that significantly reduce secondary cardiovascular events in patients with manifest atherosclerosis. However, their impact on atherosclerotic lesion development remains controversial. Four-week-old ApoE-deficient mice were randomly assigned to four groups receiving a cholesterol diet together with either ASA (5 mg/kg), or clopidogrel (25 mg/kg), or a combination of both ASA and clopidogrel, or vehicle for 8-12 weeks. ⋯ However, therapy with ASA or clopidogrel alone, or in combination for a period of 8-12 weeks had no significant effect on adhesion of platelets to dysfunctional endothelial cells or on atherosclerotic lesion formation in the aortic root or the carotid artery. In conclusion, anti-platelet therapy is effective in reducing platelet adhesion and subsequent thrombus formation following rupture of atherosclerotic plaque in vivo. However, our data do not support a role of either drug in the primary prevention of atherosclerosis in ApoE-deficient mice.