Antithrombotic Therapy in Heart Failure: A Randomized Comparison of Warfarin vs. Aspirin - HELAS


HELAS was a randomized, multicenter, placebo-controlled trial of aspirin, Coumadin, or placebo in patients with heart failure for the prevention of thromboembolism.


The hypothesis was that Coumadin is superior to aspirin and placebo in the prevention of thromboembolism among patients with heart failure.

Study Design

Study Design:

Patients Enrolled: 300
Mean Follow Up: One year
Mean Patient Age: 20-80
Mean Ejection Fraction: 28 ± 7

Patient Populations:

Age 20-80, New York Heart Association class II-IV heart failure, and left ventricular ejection fraction ≤35% by echocardiography


Myocardial infarction within two months, reversible myocardial ischemia, mitral valve disease, hypertrophic cardiomyopathy, atrial fibrillation, left ventricular thrombus on echocardiography, or contraindication to study medications

Primary Endpoints:

A composite of nonfatal stroke, peripheral embolism, pulmonary embolism, myocardial (re) infarction, worsening heart failure, or death from any cause

Secondary Endpoints:

Cerebrovascular event secondary to hemorrhage and bleeding complications

Drug/Procedures Used:

Patients with congestive heart failure were recruited and randomized to warfarin (titrated to international normalized ratio [INR] 2.0-3.0), aspirin 325 mg per day, or placebo. Planned follow-up time was two years.

Principal Findings:

The study planned to enroll 6,000 patients, to be divided up into ischemic and nonischemic cardiomyopathy groups. Within each group, the patients were to be further subdivided into three arms: warfarin (titrate to INR 2.0-3.0), aspirin 325 mg per day, or placebo. The study was stopped after 300 patients, due to difficulties with recruitment.

At the time of study discontinuation, only 50% of patients had completed a one-year follow-up. Adverse events were limited and included one embolic stroke, one myocardial infarction, five deaths, and three hemorrhagic episodes. Due to the small number of participants, no statistical conclusions could be made.


The trial was stopped early due to difficulty enrolling patients. As a result, no conclusions can be drawn regarding prevention of thromboembolism in heart failure patients with warfarin or aspirin.


Cokkinos DV, Toutouzas PK. Antithrombotic therapy in heart failure: a randomized comparison of warfarin vs. aspirin (HELAS). Eur J Heart Fail 1999;1:419-23.

Clinical Topics: Anticoagulation Management, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Vascular Medicine, Acute Heart Failure, Echocardiography/Ultrasound

Keywords: Stroke, Myocardial Infarction, Follow-Up Studies, Platelet Aggregation Inhibitors, Pulmonary Embolism, Warfarin, International Normalized Ratio, Thromboembolism, Cardiomyopathies, Heart Failure, Stroke Volume, Echocardiography

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