Level 2: Mid-level evidence
Use of aspirin for patients with heart failure (HF) is controversial. Previously, the Warfarin/Aspirin Study in Heart Failure (WASH) trial found increased hospitalization for HF in patients taking aspirin compared with patients taking either warfarin or placebo. The newly published Warfarin and Antiplatelet Therapy in Chronic Heart Failure (WATCH) trial compared the relative efficacy of warfarin, clopidogrel, and aspirin in 1,587 patients with HF followed for mean 1.9 years (Circulation. 2009;119:1616-1624; available at circ.ahajournals .org/cgi/content/full/119/12/1616, accessed June 11, 2009). Warfarin was administered open-label, but clopidogrel and aspirin groups were double-blinded. While there was no difference in the primary composite outcome of death from all causes, nonfatal MI, and nonfatal stroke, the trial did support the WASH trial findings regarding the increase in hospitalization for HF with the use of aspirin. Hospitalization for HF was significantly higher for the aspirin group compared with the warfarin group (22.2% vs. 16.5%, P =.02, NNH 17). Incidence of nonfatal stroke was lower with warfarin (0.2%) than with either aspirin (1.7%, P =.0095 vs. warfarin, NNH 66) or clopidogrel (2.1%, P =.0031 vs. warfarin, NNH 52). Mortality was about 18% overall, with no differences between groups. There were no differences in bleeding outcomes between patients taking warfarin and those taking aspirin.