There is not enough evidence to determine if anticoagulants safely prevent blood clots in patients with chronic heart failure who are in normal heart rhythm

Blood clots (thromboembolism) in the lungs, legs and brain (ischaemic stroke) contribute to disability and the death of patients with heart failure. Although anticoagulants such as warfarin are of proven benefit in patients in certain subgroups of patients with heart failure, such as those with atrial fibrillation, there is little evidence that warfarin works well in the wider heart failure population. There may also be serious side effects such as bleeding (causing ulcers and haemorrhagic stroke). At present there are no data to recommend the routine use of anticoagulants to prevent thromboembolism in patients with heart failure who are in normal heart rhythm.

Authors' conclusions: 

Based on the two major randomised trials (HELAS 2006; WASH 2004), there is no convincing evidence that oral anticoagulant therapy modifies mortality or vascular events in patients with heart failure and sinus rhythm. Although oral anticoagulation is indicated in certain groups of patients with heart failure (for example those with atrial fibrillation), the available data does not support the routine use of anticoagulation in heart failure patients who remain in sinus rhythm.

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Background: 

Patients with chronic heart failure (heart failure) are at risk of thromboembolic events, including stroke, pulmonary embolism and peripheral arterial embolism, whilst coronary ischaemic events also contribute to the progression of heart failure. Long-term oral anticoagulation is established in certain patient groups, including patients with heart failure and atrial fibrillation, but there is wide variation in the indications and use of oral anticoagulation in the broader heart failure population.

Objectives: 

To determine whether long-term oral anticoagulation reduces total deaths, cardiovascular deaths and major thromboembolic events in patients with heart failure.

Search strategy: 

We updated the searches in June 2030 in the electronic databases CENTRAL (Issue 6, 2013) in The Cochrane Library, MEDLINE (OVID, 1946 to June week 1 2013) and EMBASE (OVID, 1980 to 2013 week 23). Reference lists of papers and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors were contacted to obtain further data. No language restrictions were applied.

Selection criteria: 

Randomised controlled trials (RCTs) comparing oral anticoagulants with placebo in adults with heart failure, and with treatment duration at least one month. Non-randomised studies were also included for assessing side effects. Inclusion decisions were made in duplicate and any disagreement between review authors was resolved by discussion or a third party.

Data collection and analysis: 

Two review authors independently assessed trials for inclusion and assessed the risks and benefits of antithrombotic therapy using relative measures of effects, such as odds ratio, accompanied by the 95% confidence intervals.

Main results: 

Two RCTs were identified. One compared warfarin, aspirin and no antithrombotic therapy and the second compared warfarin with placebo in patients with idiopathic dilated cardiomyopathy. Three small prospective controlled studies of warfarin in heart failure were also identified, but they were over 50 years old with methods not considered reliable by modern standards. In both WASH 2004 and HELAS 2006, there were no significant differences in the incidence of myocardial infarction, non-fatal stroke and death between patients taking oral anticoagulation and those taking placebo. Four retrospective non-randomised cohort analyses and four observational studies of oral anticoagulation in heart failure included differing populations of heart failure patients and reported contradictory results.

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