Anticoagulation for heart failure in sinus rhythm: a Cochrane systematic review

BACKGROUND: Patients with chronic heart failure (heart failure) are at risk of thromboembolic events, and coronary ischaemic events also contribute to the progression of heart failure. Long-term oral anticoagulation is established in certain groups, including patients with heart failure and atrial fibrillation, but there is wide variation in the use of oral anticoagulation in the broader heart failure population. OBJECTIVE: To determine whether long-term oral anticoagulation reduces total deaths and/or major thromboembolic events in patients with heart failure. DESIGN:Systematic review. DATA SOURCES: Reference lists of papers resulting from this search, electronic database searching (MEDLINE, EMBASE, DARE), and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors of these studies were contacted to obtain further data. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing oral anticoagulants with control or placebo. Non-randomized studies were included, as they may help in assessing side-effects. Other inclusion criteria included duration of treatment > or =1 month, and adults with heart failure due to any underlying cause. Inclusion decisions were duplicated, and disagreement resolved by discussion or a third party. RESULTS: One recent pilot RCT compared warfarin, aspirin and no antithrombotic therapy, but no definitive data have yet been published. Three small prospective studies of warfarin in heart failure were also identified, but were over 50 years old, with methods considered unreliable today: in these, anticoagulation was more efficacious than control in reducing all-cause death (OR 0.64; 95%CI 0.45-0.90) and cardiovascular events (OR 0.26; 95%CI 0.16-0.43). Four retrospective non-randomized cohort analyses and three small observational studies of oral anticoagulation in heart failure included differing populations of heart failure patients, and reported contradictory results. CONCLUSIONS: Limited evidence from randomized trials and observational studies found a reduction in mortality and cardiovascular events with anticoagulants compared to controls. This evidence should be interpreted with caution. Although oral anticoagulation is indicated in certain groups of patients with heart failure (e.g. atrial fibrillation), the available data do not support its routine use in heart failure patients who remain in sinus rhythm.