What's the best antithrombotic in chronic HF? WATCH this space here

March 10, 2004

Wed, 10 Mar 2004 22:54:36

New Orleans, LA - More than most other subspecialties, cardiology is rich with evidenced-based care guidelines, although some prominent gaps remain. Among them: how best to prevent stroke, MI, and other thrombotic complications in patients with chronic HF. The Warfarin and Antiplatelet Therapy in Heart Failure Trial (WATCH), halted prematurely due to a shortfall in patient enrollment, took aim at that question but failed to come up with an answer.

Dr Barry M Massie

The WATCH trial found few significant outcome differences among 1587 patients with chronic ischemic or nonischemic HF and an LVEF <35% who had been randomized to open-label warfarin or double-blind aspirin or clopidogrel. Rates of death, MI, and strokeindividually and as a composite end pointwere similar among the groups over a mean 23-month follow-up, Dr Barry M Massie (University of California, San Francisco) reported here.

On the other hand, 27% fewer patients taking warfarin than those on aspirin were hospitalized for HF, a "fascinating, and the trial's only significant, finding," said Massie in his formal presentation.


There are a few groups of patients in whom I've become cautious and I don't use aspirin.


The finding seems consistent with prior studies suggesting that prostaglandin suppression by nonsteroidal anti-inflammatory drugs may promote or worsen HF, according to Massie. But he cautioned against interpreting WATCH as suggesting that aspirin should be stopped in patients with chronic HF. "However, personally, there are a few groups of patients in whom I've become cautious and I don't use aspirin." These include patients with dilated cardiomyopathy and no evidence of vascular disease in whom there is evidence of a detrimental effect, he said. He also avoids adding aspirin on top of warfarin or other antiplatelet agents as potentially being excessive. "That's why we didn't have a combined-therapy group in this trial."

The population enrolled at 142 sites in the US, Canada, and the UK represented only about 40% of the protocol-stipulated target. Interpretation of the trial was further complicated by a series of midstream protocol changes, which were intended to enhance enrollment or add statistical power to outcomes in a smaller-than-anticipated population.

Clinical and safety outcomes in WATCH, 23-month mean follow-up


Aspirin (n=523)

Warfarin (n=540)

Clopidogrel (n=524)

*p=0.01 vs warfarin**p=0.012 vs warfarin

Antiplatelet dosages and warfarin anticoagulation target range in WATCH


Aspirin (n=523)

Warfarin (n=540)

Clopidogrel (n=524)

162 mg/day
INR* 2.5-3.0
75 mg/day
*International normalized ratio; target reached by 31% of warfarin recipients; mean INR, 2.6.To download tables as slides, click on slide logo below

Related links

1. Garg RK, Gheorghiade M, Jafri SM. Antiplatelet and anticoagulant therapy in the prevention of thromboemboli in chronic heart failure. Prog Cardiovasc Dis 1998 Nov-Dec; 41(3):225-36. 2. Diet F, Erdmann E. Thromboembolism in heart failure: who should be treated? Eur J Heart Fail 2000 Dec; 2(4):355-63.


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