According to researchers Aspirin could be as effective as more expensive drugs for heart failure patients with a normal heart rhythm.
Heart failure is a major health problem in many parts of the world. It affects 900,000 people in the UK and six million people in the US. A failing heart struggles to pump blood around the body, meaning even trivial tasks become exhausting. As the blood is not pumped round the body as efficiently the risk of a blood clot increases, if a clot blocks blood to parts of the brain it will result in a stroke. Patients are treated with drugs to reduce the risk of a fatal blood clot forming. However, researchers said it was unknown whether aspirin or warfarin was the better treatment in the 75% of heart failure patients who still have a normal heart beat.
In a new study on more than 2,000 patients, published in the New England Journal of Medicine, researchers found that aspirin was as effective as the commonly prescribed drug warfarin. It said each drug had risks, but they had similar benefits overall.
Researchers gave 2,305 patients, in 11 countries, either aspirin or warfarin. The combined risk of death, stroke and major bleeding was the same for each drug, according to the researchers.
In the head-to-head comparison, the combined risk of death, stroke, and cerebral hemorrhage was 7.47 per cent per year for patients taking the blood-thinner warfarin, also known by its brand name Coumadin, and 7.93 per cent per year for those taking aspirin - a difference that is not statistically significant. Patients taking warfarin had a stroke risk of 0.72 per cent per year compared to 1.36 per cent for aspirin. Warfarin patients also had a 1.8 per cent risk of major bleeding compared to 0.87 per cent for aspirin. In patients followed four years or longer, there was evidence that warfarin may be more effective in preventing the combined outcome of death, stroke, and intracerebral hemorrhage. The researchers said further investigation would be needed. But they concluded, “There is no compelling reason to use warfarin rather than aspirin.”
The lead researcher, Dr Shunichi Homma, from the Columbia University Medical Center, said, “Since the overall risks and benefits are similar for aspirin and warfarin, the patient and his or her doctor are free to choose the treatment that best meets their particular medical needs. However, given the convenience and low cost of aspirin, many may go this route.”
Dr Andrew Clark, from the British Society for Heart Failure and the University of Hull, told the BBC, “The study shown here demonstrates that warfarin quite markedly reduces the risk of stroke associated with heart failure compared with aspirin, but at a cost of an increase in major haemorrhage. How to interpret that for individual patients means weighing the risk of stroke against the risk of haemorrhage, but also weighting that by importance. I would regard a gastrointestinal haemorrhage requiring transfusion as being of less importance than a stroke, so would tend in favour of warfarin. I would be more inclined to prescribe warfarin that previously, but the evidence is not overwhelming.”
Dr Walter Koroshetz, who is the deputy director of the US National Institute for Neurological Disorders and Stroke, said the study would have “a large public health impact”. He added, “Patients and their physicians now have critical information to help select the optimum treatment. The key decision will be whether to accept the increased risk of stroke with aspirin, or the increased risk of primarily gastrointestinal haemorrhage with warfarin.” The British Heart Foundation said both warfarin and aspirin had risks and benefits, but this study showed “neither has an advantage over the other overall in preventing stroke or death in the long term.”
Ellen Mason, a senior cardiac nurse at the charity, said, “This finding should give patients reassurance when discussing their medication with their heart failure specialist, and more freedom to choose the treatment which works best for them.”
An accompanying editorial in the journal by John Eikelboom and Stuart Connolly said, “The trial provides clear evidence that anti-coagulant therapy prevents stroke in patients with heart failure who have severe systolic dysfunction but the rates of strok are too low to justify the routine clinical use of warfarin in most patients with heart failure, in light of the increase in the risk of bleeding.” They added that patients with heart failure who also have rhythm disturbances, called atrial fibrillation and people who have had a heart attack would still benefit from warfarin.
Dr Clare Walton, Research Communications Officer at the Stroke Association said, “Aspirin and warfarin are both used to treat patients who may be at risk of stroke. This study shows that neither medication is better than the other at preventing strokes in patients suffering from heart failure. However, the two treatments have different risks and benefits; warfarin is better at preventing strokes caused by blood clots but can increase the likelihood of bleeding in the brain. It is therefore vital that every patient has their risks assessed and are treated on a case by case basis to ensure they receive the best possible treatment for them.”
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