Antithrombotic therapy in heart failure: a randomized comparison of warfarin vs. aspirin (HELAS)

It is uncertain whether anti-thrombotic treatment reduces the incidence of thrombo-embolism in patients with heart failure, so there is a need for a l arge scale controlled study to assess the effects of anti-thrombotic therap y in this setting. We report the design of a randomized controlled multicen ter double blind trial examining the effects of aspirin, warfarin and place bo in patients with heart failure on the risk of thrombo-embolism. We plann ed to recruit 6000 patients with heart failure without contraindications to anticoagulants or antiplatelet agents and to follow them for a mean time o f 2 years following randomization. The study was planned to determine the r ate of thrombo-embolic and haemorrhagic events and death among patients ran domized to aspirin, warfarin and placebo, stratified according to the prese nce or absence of underlying coronary disease. Ancillary studies parallel t o the main study will attempt to identify clinical and echocardiographic ri sk factors for thrombo-embolism and will also examine whether hemostatic or neurohormonal mechanisms contribute to an increase in the risk of thrombo- embolism in patients with heart failure. We hoped that the results of the s tudy would improve the clinical management and cost-effectiveness of treatm ent for patients with heart failure. However, the recruitment of patients p roved more difficult than expected and a number of centers decided not to p articipate. To avoid a great delay it was decided by the principal investig ators and submitted to the executive committee to terminate enrolment in th is study when 300 patients had been enrolled, and accept that this is a pil ot study. (C) 1999 European Society of Cardiology. All rights reserved..