Biomedical subjects

Michael D Ezekowitz

Publications and source records attributed to Michael D Ezekowitz.

23 records · Page 2Linked to original sources

PubMed2002

Department of Veterans Affairs Cooperative Studies Program Clinical Trial comparing combined warfarin and aspirin with aspirin alone in survivors of acute myocardial infarction: primary results of the CHAMP study.

BACKGROUND: Both aspirin and warfarin when used alone are effective in the secondary prevention of vascular events and death after acute myocardial infarction. We tested the hypothesis that aspirin and warfarin therapy, when combined, would be more effective than aspirin monotherapy. Methods and Results- We conducted a randomized open-label study to compare the efficacy of warfarin (target international normalized ratio 1.5 to 2.5 IU) plus aspirin (81 mg daily) with the efficacy of aspirin monotherapy (162 mg daily) in reducing the total mortality in 5059 patients enrolled within 14 days of infarction and followed for a median of 2.7 years. Secondary end points included recurrent myocardial infarction, stroke, and major hemorrhage. Four hundred thirty-eight (17.3%) of 2537 patients assigned to the aspirin group and 444 (17.6%) of 2522 patients assigned to the combination group died (log-rank P=0.76). Recurrent myocardial infarction occurred in 333 patients (13.1%) taking aspirin and in 336 patients (13.3%) taking combination therapy (log-rank P=0.78). Stroke occurred in 89 patients (3.5%) taking aspirin and in 79 patients (3.1%) taking combination therapy (log-rank P=0.52). Major bleeding occurred more frequently in the combination therapy group than in the aspirin group (1.28 versus 0.72 events per 100 person years of follow-up, respectively; P<0.001). There were 14 individuals with intracranial bleeds in both the aspirin and combination therapy groups. CONCLUSIONS: In post-myocardial infarction patients, warfarin therapy (at a mean international normalized ratio of 1.8) combined with low-dose aspirin did not provide a clinical benefit beyond that achievable with aspirin monotherapy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2002

Anticoagulation management of valve replacement patients.

Anticoagulation regimens vary according to surgeon, nature of the valve (mechanical or biological), its position and other risk factors for stroke. The American College of Chest Physicians (2001) have made the following recommendations to protect patients with prosthetic heart valves from developing a stroke: (i) For mechanical heart valves: Anticoagulation with Warfarin at an INR range 2-3 for patients with a bileaflet mechanical valve in the aortic position; (ii) in the mitral position, an INR of 2.5-3.5 is recommended; an alternative recommendation is an INR of 2-3 in combination with aspirin (80 mg/day); and (iii) in patients with a mechanical valve and a history of systemic embolization, an INR of 2.5-3.5 combined with low-dose aspirin (80-100 mg) is recommended; when Warfarin therapy is initiated, the doses for patients aged <70 years is 4 mg, and for patients aged >70 years it is 3 mg. While it is important to recognize that the therapeutic range for Warfarin is narrow, recommendations have also been established to manage patients with high INRs and for the temporary discontinuation of anticoagulant therapy when they undergo surgical procedures. Rapid anticoagulation can be achieved either with unfractionated heparin or with low-molecular weight heparin (LMWH). Heparin is initiated with an intravenous bolus of 80 U/kg bodyweight, and an infusion of 18 U/kg/h. The activated thromboplastin time should be 60-80 s. An alternative to intravenous heparin is subcutaneous LMWH, which is prescribed in a mg/kg dose. In the event of valve thrombosis in patients who are hemodynamically unstable, surgical exploration with thrombectomy is indicated, with or without valve replacement. In patients who are hemodynamically stable, thrombolytic therapy is recommended initially.

Anticoagulants↗

PubMed2002

Cholesterol-induced thrombogenicity of the vessel wall: inhibitory effect of fluvastatin.

High cholesterol levels are a known risk factor for coronary events. The molecular links between high serum cholesterol and the increased thrombogenicity of the arterial wall are still matter of investigation. In the present study we investigate the relationship between plasma cholesterol, thrombus formation and TF expression in a atherosclerotic rabbit model. Hypercholesterolemic rabbits showed a pronounced TF staining as well as NF-kappaB activation in the aortic arch. A consistent vessel wall platelet deposition was also observed. Treatment with fluvastatin reduced lipid accumulation, TF overexpression (-60%), NF-kappaB activation, and platelet deposition (-56%). In vitro studies showed that the drug upregulated IkappaB alpha in unstimulated as well as in TNFalpha-stimulated cells and also impaired the TNFalpha-induced Cdc42 prenylation, indicating that fluvastatin interferes with the transcriptional activation of TF gene. These results indicate that the prothrombotic phenotype of arterial wall, associated with elevated serum cholesterol levels, is mediated by TF overexpression. Fluvastatin treatment reduces the prothrombotic tendency by inhibiting TF synthesis.

Animals↗

PubMedDate not supplied

Anticoagulation in the elderly.

This review will address the general approach to the management of the typical elderly patient requiring anticoagulation. Most of the data has been derived from studies of patients with nonvalvular atrial fibrillation. Data from postmyocardial infarction trials have also been included. A practical clinical approach to anticoagulation in the elderly is described. Emphasis has been placed on maximizing the benefit and reducing the risk of anticoagulation in the rapidly expanding group of elderly patients aged >/=75 who are at the greatest risk of stroke and are likely to benefit the most from antithrombotic therapy.

Age Distribution↗

PubMedDate not supplied

Tissue factor pathway inhibitors as a novel approach to antithrombotic therapy.

Tissue factor is the initiator of the extrinsic pathway of the coagulation cascade. It is expressed by endothelial cells when stimulated by cytokines and other mediators. The effect of tissue factor is physiologically balanced by tissue factor pathway inhibitor. Atherosclerotic plaques are rich in tissue factor. It stimulates thrombus formation when plaques rupture. The emerging role of tissue factor in cellular signaling and in the pathogenesis of atherosclerosis has directed attention to inhibitors of tissue factor as a new antithrombotic approach. In comparison to currently used anticoagulants, tissue factor pathway inhibitors have the potential advantage of inhibiting the coagulation cascade at its earliest stage. These agents also act locally at the site of endothelial injury with minimal disturbance of systemic hemostasis. In addition, their inhibitory effect on neointimal formation and restenosis after vascular intervention are appealing features in the management of the complications of atherosclerosis.

Animals↗