Study Suggests Neither Warfarin nor Clopidogrel Superior to Aspirin as Antiplatelet Therapy for Chronic Heart Failure
Chronic heart failure remains a major cause of morbidity and mortality. The Warfarin and Antiplatelet Therapy in Chronic Heart Failure (WATCH) Trial was conducted to determine the optimal anti-thrombotic agent for heart failure patients with reduced ejection fraction who are in sinus rhythm. The two main hypotheses of the WATCH Trial were: 1) anticoagulation with warfarin is superior to antiplatelet therapy with aspirin in preventing major cardiovascular outcomes, and 2) clopidogrel is superior to aspirin in this patient population. Investigators assessed occurrences of mortality, non-fatal myocardial infarction (MI), or non-fatal stroke in 1,587 men and women with heart failure, >18 years, who received care at 142 hospitals or clinics in the U.S. (including 44 VA sites), Canada, and the U.K. between 10/99 and 6/02. Of the 1,587 participants, 523 were assigned to aspirin, 524 to clopidogrel, and 540 to warfarin.
WATCH Trial findings do not support the primary hypotheses that warfarin or clopidogrel is superior to aspirin. For the primary combined outcome of mortality, non-fatal MI, or non-fatal stroke, major differences between anticoagulation with warfarin and anti-platelet therapy with aspirin or clopidogrel are unlikely. Warfarin was associated with fewer non-fatal strokes than aspirin or clopidogrel, but also was associated with more frequent bleeding episodes compared to clopidogrel, and a non-significant excess of bleeding compared to aspirin. Therefore, while the use of warfarin rather than aspirin or clopidogrel may have resulted in reduced strokes, this benefit may be offset by increased risk from bleeding. The authors also note that while their findings do not support the avoidance of aspirin in patients with heart failure in sinus rhythm, they also provide no evidence to support its use.
Massie B, Collins J, Ammon S, et al. A randomized trial of warfarin, aspirin, and clopidogrel in patients with chronic heart failure: The Warfarin and Antiplatelet Therapy in Chronic Heart Failure Trial (WATCH). Circulation March 31, 2009;119(12):1616-24.
This study was supported through VA’s Cooperative Studies Program. Dr. Massie is part of VA/HSR&D’s Chronic Heart Failure Quality Enhancement Research Initiative (CHF-QUERI); he and Dr. Ammon are part of the San Francisco VAMC.