The angiotensin-converting enzyme inhibitor and aspirin interaction in congestive heart failure: fear or reality?

Angiotensin-converting enzyme (ACE) inhibitors have become the cornerstone of therapy for congestive heart failure (CHF). Because ischemic heart disease is the most common cause of CHF, aspirin is frequently given concomitantly with ACE inhibitors in patients with CHF. Increased bradykinin levels, with the consequent enhanced synthesis of vasodilatory prostaglandins, appear to mediate a significant benefit of ACE inhibitor therapy in these patients. In contrast, aspirin inhibits cyclooxygenase, and thereby suppresses prostaglandin production. Thus, these counteracting effects on prostaglandins may result in antagonism between ACE inhibitor and aspirin therapy in heart failure patients. Several early reports questioned the safety of aspirin in CHF, and the potential antagonistic interaction between ACE inhibitors and aspirin in patients with heart failure has become the focus of both increasing research and intense debate. This article briefly highlights the theoretic considerations underlying this interaction, and reviews the available evidence for such an interaction from clinical trials.