Several studies have evaluated a possible interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors in the treatment of congestive heart failure. Some studies have suggested that aspirin therapy may attenuate the benefit of ACE inhibitors in heart failure survival. Others have found that aspirin does not negatively affect heart failure survival when combined with ACE inhibitors. The use of different aspirin dosages in the studies may have led to the conflicting results. In one study, low-dose aspirin did not interfere with ACE inhibitor therapy. Aumégeat and associates conducted a retrospective analysis to assess the effect of aspirin on survival in stable patients with left ventricular systolic dysfunction who had congestive heart failure and were treated with ACE inhibitors.

Patients were eligible for the study if they were ambulatory and symptomatically stable for the preceding two months. They were evaluated by echocardiography and cardiopulmonary exercise testing. The presence of nonischemic or ischemic cardiomyopathy was identified. Medications and dosages were recorded at the start of the study and information on medication changes was obtained during the follow-up period. The major end points were cardiovascular-related deaths and cardiovascular events.

Of 755 patients enrolled in the study, 328 had ischemic cardiomyopathy, 693 were receiving ACE inhibitors, and 317 were receiving aspirin therapy. Of the patients receiving aspirin, 74 percent were taking 200 mg or less per day. The median follow-up period was 1,996 days. During this period, 273 cardiac deaths, 14 urgent cardiac transplantations, 71 nonurgent transplantations, and 46 non-cardiac-related deaths occurred. When testing for a possible interaction between aspirin therapy and ACE inhibitors, there were no significant differences in survival rates in the group that received both medications and the group that received only ACE inhibitors. There also were no significant differences in survival rates in patients with ischemic or nonischemic cardiomyopathy.

The authors conclude that in patients with stable congestive heart failure, there is no interaction between ACE inhibitors and aspirin that affects survival. They note that the patients in their study used small dosages of aspirin. They recommend that aspirin dosages of less than 200 mg per day be used in patients with stable congestive heart failure who have known coronary artery disease or peripheral atherosclerosis.