CHICAGO—Millions of heart patients whose disease has been treated with tiny devices called stents may need to stay on an aggressive course of blood-thinning drugs longer than current practice to get the most protection against future heart attacks, a major study presented Sunday suggests.
In the study, which involved nearly 10,000 patients, those treated with aspirin plus a second anticlotting drug for 30 months had a sharp reduction in the risk of heart attacks and other complications compared with those who stopped one of the blood thinners after a year.
But prolonged use of a dual-agent strategy comes with increased risk of significant bleeding problems. Some patients experience annoying side effects such as nose bleeds and bruising. Experts said the challenge for doctors and patients alike is weighing the benefits versus risks in determining how long to remain on the therapy.
Current U.S. guidelines call for doctors to prescribe what is called dual-antiplatelet therapy for 12 months, and some cardiologists have urged even shorter treatment.
Stents are tiny wire mesh devices that are implanted to prop open diseased coronary arteries. They are commonly used to treat patients suffering a heart attack or chest pain called unstable angina that is a precursor to a heart attack.
The two-drug strategy is intended to reduce the risk of clots forming in the stent, which has long been a concern in the first few months after the device is implanted. Clopidogrel, which was marketed as Plavix by Bristol-Myers Squibb Co. and Sanofi SA before it went generic in 2012, is the most widely used such drug with aspirin. Eli Lilly & Co.'s prasugrel is another antiplatelet agent.
In 2006, researchers cited rare but unexpected reports of life-threatening clots forming in stents long after doctors figured such a threat was over. That led to confusion over how long patients needed to be prescribed the two-drug strategy and wide variation in physician practice. The U.S. Food and Drug Administration requested the current study to assess the late-clotting risk.
"We face this decision every day about how long patients should continue" on two antiplatelet medicines, said Laura Mauri, a cardiologist at Harvard-associated Brigham and Women's Hospital and co-principal investigator of the study. She presented the results at the annual scientific meeting of the American Heart Association. They were also published online by the New England Journal of Medicine.