Purpose: The potentially beneficial hemodynamic effects of angiotensin-converting enzyme (ACE) inhibitors in heart failure may relate, in part, to their ability to increase the production of vasodilator prostanoids. Low dose aspirin is commonly prescribed in CHF and may attenuate the vasodilator effects of ACE inhibitors. We sought to determine the effects of low dose aspirin on the peripheral hemodynamic effects of captopril in patients with chronic heart failure (CHF).
Methods: Nine patients with chronic heart failure were randomized in a placebo controlled, cross over study, to 75 mg of aspirin daily or placebo. After 7 days treatment the response to 25 mg of captopril was evaluated over 180 min using venous occlusion plethysmography. Forearm blood flow (FBF) and forearm venous capacitance (FVC) were measured.
Results: Mean arterial pressure and heart rate did not change. After placebo, FBF increased in response to captopril (+18%, 95%CI 24.2, 11.8), a response inhibited by aspirin (-1.4%, 2.9, -5.7), p < 0.005. After placebo, FVC increased in response to captopril (+7.6%, 9.8, 5.4), which was also inhibited by aspirin (+2.0%, 4.6, -0.6), aspirin vs. placebo, p = 0.02).
Conclusion: In patients with chronic heart failure even low dose aspirin inhibits both the acute arterial and venous dilator responses to captopril. This action of aspirin may reduce the long-term clinical benefits of ACE inhibitors.