1223-Feature-Top Ten-warfarin AFib_Blog

Editor’s note: This is one in a 10-part series of the top medical research advances as determined by American Heart Association volunteer and staff leaders.

Preparing for surgery has become simpler and safer for most atrial fibrillation patients after a practice-changing study found they can temporarily stop taking blood thinners.

Because AFib increases the risk of blood clots, doctors would often “bridge” patients before and after surgery from the powerful blood thinner warfarin to another faster-acting blood thinner called low-molecular-weight heparin.

But bridging did not reduce the risk of stroke and in fact increased the risk of major bleeding, researchers reported this summer in the New England Journal of Medicine.

The study, sponsored by the National Heart, Lung, and Blood Institute, was selected as one of the top 10 research advances in 2015.

“For the vast majority of patients, it has changed clinical practice overnight,” said Patrick T. Ellinor, M.D., Ph.D., from the Cardiac Arrhythmia Service at Massachusetts General Hospital Heart Center and Harvard Medical School. Ellinor was not involved with the study.

The findings provided clarity to inconsistent guidelines that affect an estimated 250,000 North American patients who take warfarin, primarily for AFib, and require routine procedures or surgeries each year, said Thomas L. Ortel, M.D., Ph.D., who led the trial, known as BRIDGE.

“We clearly showed that we weren’t benefiting patients by doing this practice and we were potentially making things worse,” said Ortel, who called the findings “guideline-changing.”

Warfarin takes several days to stop working and several more days to start working again. The therapy has long raised questions about how best to manage AFib patients before and after procedures without increasing the risk of blood clots or bleeding.

For patients, the bridging therapy meant a complicated schedule of stopping their regular blood thinner and self-administering expensive twice-daily injections.

Among more than 1,800 U.S. and Canadian patients in the study, 0.3 percent of patients treated with bridging medication developed a clot compared with 0.4 percent taking a placebo.

Although major bleeding was uncommon overall, the risk more than doubled among patients given bridging therapy – 3.2 percent compared with 1.3 percent in the placebo group. There was also a lower risk of minor bleeding in the group foregoing bridging medication.

The rates of heart attack, deep vein thrombosis and death were similar between the two groups. Patients with mechanical heart valves were not included in the trial.

“This was a very challenging area, and this study makes very clear what to do,” Ellinor said. “It’s going to be a lot less hassle, both for patients and clinicians.”