CHICAGO – The four studies reported during the American Heart Association Scientific Sessions that looked at the safety and efficacy of different durations of dual antiplatelet therapy following coronary stenting addressed two different issues.
Two of the studies, ISAR-SAFE and ITALIC, both based in Europe, addressed the question of whether 6 months of dual antiplatelet therapy (DAPT) was as safe and effective as either 12 or 24 months of treatment, and the results from both studies indicated that a 6-month duration is as effective as longer term treatment. This means that especially for patients with an increased bleeding risk or another good reason to stop DAPT in the short term, such as patients who need surgery or those with atrial fibrillation who need treatment with an oral anticoagulant, stopping DAPT after 6 months is a reasonable and safe approach, Dr. Gilles Montalescot said during an interview at the meeting. More than half the patients who undergo coronary artery stenting likely fall into this subgroup, and perhaps as many as 60% or 70% of patients, estimated Dr. Montalescot, a professor of cardiology at the University of Paris and director of the cardiac care unit at Pitié-Salpêtrière Hospital in Paris.
But results from the other two DAPT trials reported at the meeting, TAXUS Liberté and DAPT, showed that for the subgroup of patients who can reasonably continue on DAPT beyond 6 months continuing the treatment out to 30 months led to substantially fewer ischemic events compared with patients who came off DAPT after 12 months, with a modest increase in bleeding events. Hence, for patients with a reduced risk for bleeding, more prolonged DAPT treatment, for as long as 30 months, produced a net benefit.
Many of the ischemic events prevented by more prolonged DAPT occurred in coronary sites outside of the placed stents, suggesting that this benefit is due more to secondary coronary disease prevention rather than prevention of late stent thrombosis, noted Dr. Montalescot. This raises the question of whether DAPT should continue indefinitely in coronary disease patients with a low bleeding risk. The current trial results do not fully resolve this, but if results from another study, PEGASUS, expected next March show similar findings, the accumulated data may support very long-term DAPT treatment in selected patients with coronary artery disease.
Dr. Montalescot said that he has been a consultant to more than a dozen pharmaceutical and device companies, including companies that market antiplatelet drugs.
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