Boston—Standard practice has been to prescribe months or even years of antiplatelet drugs to cardiovascular disease patients who have undergone surgery to have stents placed in narrowed coronary arteries.
A new analysis published in the journal Circulation calls that treatment regimen into question, however. Researchers from Massachusetts General Hospital (MGH) and Beth Israel Deaconess Medical Center question whether the practice is outdated and not optimal for most patients now.

The treatment plan was put into place as a result of the Dual Antiplatelet Therapy (DAPT) study, which enrolled patients a decade ago. Results were reported in the New England Journal of Medicine in 2014. DAPT authors reported that long-term use of the drugs prevented clots within stents and reduced the risk of major adverse cardiovascular and cerebrovascular events. The more recent analysis suggests that today’s patients may be different from those who participated in the trial and that stent technology has improved in recent years.

“Differences in patient characteristics, changes in treatment algorithms, and advances in medical technology could each influence the applicability of older randomized trial results to contemporary clinical practice,” the authors write. “The Dual Antiplatelet Therapy (DAPT) Study found that longer duration DAPT decreased ischemic events at the expense of greater bleeding, but subsequent evolution in stent technology and clinical practice may attenuate the benefit of prolonged DAPT in a contemporary population. We evaluated whether the DAPT Study population is different from a contemporary population of U.S. patients receiving percutaneous coronary intervention (PCI) and estimated the treatment effect of extended duration antiplatelet therapy after PCI in this more contemporary cohort.”

To find out if their hypothesis was correct, the researchers compared characteristics of 8,864 DAPT patients to 568,540 contemporary patients with similar cardiovascular conditions. They determined that contemporary patients were likely to have more comorbidities, to have had a myocardial infarction, and to have received second-generation drug-eluting stents, which are coated with time-release medications and are more advanced than earlier stents.

Because of that, the authors suggest the benefits of extended use of antiplatelet drugs are reduced while dangers are increased. They recommend the use of the medications for only a short time after stent procedures.

“When we first published the study, we demonstrated that there was a clear benefit to taking a long duration of antiplatelet therapy for a large swath of patients undergoing heart stent procedures. But when we updated those results to incorporate the important changes that have occurred over the previous decade, much of the benefit of combination antiplatelet therapy had disappeared,” said senior author Robert W. Yeh, MD, MSc, who, in addition to being the senior author of the Circulation analysis, was a coauthor of the original DAPT Study results published in NEJM.

The researchers advise that, after reweighting trial results to represent the contemporary population, “there was no longer a significant effect of prolonged DAPT on reducing stent thrombosis (reweighted treatment effect: 0.40, 95% CI: 0.99%, 0.15%), major adverse cardiac and cerebrovascular events (reweighted treatment effect: 0.52, 95% CI: 2.62%, 1.03%), or myocardial infarction (reweighted treatment effect: 0.97%, 95% CI: 2.75%, 0.18%), but the increase in bleeding with prolonged DAPT persisted (reweighted treatment effect: 2.42%, 95% CI: 0.79%, 3.91%).”

Neel M. Butala, MD, MBA, an interventional cardiology fellow at MGH, recommends against long-term antiplatelet therapy for many, if not most, patients who have stents in their coronary arteries. “Instead, shorter regimens, sometimes as short as three or six months, may be a more typical duration to take these medications for the average cardiac patient,” he said.

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