Scientists tested blood thinners for this common heart condition with surprising results

Blood thinners, like aspirin, have long been used to treat this common heart condition, but the risks have now been found to outweigh the benefits.

Patients successfully treated for a common heart rhythm disorder may no longer need blood thinners, a major study has found.

So crucial were the findings of the international OCEAN study of the use of blood thinners in patients with atrial fibrillation (AF) it was stopped early and is now set to change treatment guidelines globally.

Around 500,000 Australians are affected by AF and the treatment is typically an ablation procedure that blocks the irregular electrical signals causing the heart to beat abnormally.

Until this study, which will be presented at the American Heart Association meeting in New Orleans and published in the New England Journal of Medicine, patients were then placed on blood thinners such as aspirin or anticoagulants for life.

The international team of researchers said they found such a low rate of strokes that there would be no benefit in doing this.

Blood thinners are prescribed to help prevent strokes by preventing clots from forming within the heart. Serious side effects can include severe bleeding.

Current guidelines in many countries, including Australia, calls for their use indefinitely after AF therapy based on the risk of a potential stroke rather than the success of the ablation procedure.

Cardiologist Professor Prash Sanders led the Australian arm of the study which found the risks of blood thinners outweigh the benefits.

Australian lead author Professor Prash Sanders, from the Centre for Heart Rhythm Disorders in Adelaide, said the study was stopped because the event rate of having a stroke in this group of patients was “so, so small”.

“The risks (of blood thinners) outweighs the benefits,” he said.

Professor Sanders said the researchers followed 1284 patients, including around 300 Australians, for three years. They were all a year post successful ablation and had not had any recurrent heart rhythm disorder before joining the trial.

Half were placed on aspirin and half on an anticoagulant drug to investigate which was better.

The researchers said major bleeding (reported in 11 patients) was similar in both groups and 14 people suffered strokes.

The study came about because experts could not agree on the use of blood thinners in patients with a common heart rhythm disorder. Picture: iStock

The results of such small number of adverse outcomes confirmed for the researchers the risk of stroke after an ablation was “very low” and not reduced by either aspirin or the anticoagulant drug.

Professor Sanders said the study came about because experts could not agree on the use of blood thinners in AF patients who had been successfully treated with ablation.

“When you don’t have data, it is all about opinions,” he said. “And so we all realised the only way to fix that was with a study to find out.”

He said the results opened the door for other reviews of blood thinners used as standard therapy.

Originally published as Scientists tested blood thinners for this common heart condition with surprising results