Aspirin is established as an effective antithrombotic: 325 mg daily decreased the incidence of myocardial infarction and death in asymptomatic male physicians, and 75 mg daily halved it in patients with unstable angina. Aspirin reduces stroke and death in patients with a history of transient ischemic attacks, and stroke and systemic embolism in atrial fibrillation. Although no randomized study has tested its effect on thromboembolic risk reduction in dilated cardiomyopathy, clinical trials in congestive heart failure suggest that it may be beneficial.
The Vasodilator-Heart Failure Trial I (V-HeFT I) found an incidence of thromboembolism of 0.5 events/100 patient-years in patients receiving aspirin monotherapy vs 2.7 events/100 patient-years in those not receiving antiplatelet or anticoagulant therapy. Similarly, V-HeFT
II found an incidence of 1.6 events/100 patient-years in patients receiving aspirin vs 2.1 events/100 patient-years in untreated patients (the difference was not significant). In the Survival And Ventricular Enlargement (SAVE) study, aspirin significandy reduced stroke by 56%. Protection was greatest, 66%, in patients with a left ventric-
Adverse interaction between aspirin and angiotensin-converting enzyme inhibitors remains unconfirmed. SOLVD observed significant interaction between antiplatelet use, randomization to enalapril, and allcause mortality. Enalapril had no influence on survival in patients receiving antiplatelet therapy, but did confer benefit on the combined end point of death/hospitalization for heart failure. This could be explained by antagonism between the antiplatelet agent and enalapril. Evidence from other studies has indeed suggested that aspirin reverses the vasodilator effects of enalapril, but high doses were used, and other studies failed to confirm these results. Antithrombotic prescribing in heart failure awaits clarification from a conclusive study.
Koniaris LS, Goldhaber SZ. Anticoagulation in dilated cardiomyopathy. J Am Coll Cardiol. 1998;31:745-748.
Remme WJ, Swed berg K. Guidelines for diagnosis and treatment of chronic heart failure. Task Force for the Diagnosis and Treatment of Chronic Heart Failure, European Society of Cardiology. Eur Heart J. 2001; 22:1527-1560.
drug; antiplatelet therapy; aspirin; ACEI; side effect; pharmacological interaction