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A systematic review of published evidence has failed to elucidate the optimal duration of dual antiplatelet therapy (DAPT) in patients who have a drug-eluting stent.
The data showed that patients who received DAPT for a longer period had a small reduction in myocardial infarction as well as a small increase in major bleeding and an even smaller increase in all-cause mortality, compared to patients who received DAPT for a shorter period.
Frederick A. Spencer, MD, of McMaster University in Hamilton, Ontario, Canada, and his colleagues reported these findings in Annals of Internal Medicine.
The team searched databases for trials of DAPT published from 1996 to March 2015. They identified 9 randomized, controlled trials including a total of 29,531 patients. There was complete data for 28,808 patients who had coronary artery disease and received DAPT after drug-eluting stent placement.
In 4 of the trials, patients were randomized to DAPT when they received their stent. Patients in the shorter-duration arm received DAPT for 3 to 6 months, and patients in the longer-duration arm received DAPT for 12 to 24 months.
In a fifth study, patients were randomized to DAPT at stent placement, but thrombotic events occurring during the first 6 months (when both arms received DAPT) were excluded.
In the 4 remaining trials, patients were randomized to DAPT 6 months or more after stent placement. Patients in the shorter-duration arm received DAPT for 6 to 18 months, and patients in the longer-duration arm received DAPT for 12 to 42 months.
Analyzing data from these trials together, Dr Spencer and his colleagues found moderate-quality evidence suggesting that receiving DAPT for a longer period decreased the risk of myocardial infarction (risk ratio [RR]=0.73) but increased the risk of mortality (RR=1.19).
The team also said there was high-quality evidence suggesting that longer-duration DAPT increased the risk of major bleeding (RR=1.63).
Receiving DAPT for a longer period was associated with approximately 8 fewer myocardial infarctions per 1000 patients per year, 6 more major bleeding events per 1000 patients per year, and 2 more deaths per 1000 patients per year, when compared to shorter-duration DAPT.
Because these differences are small, Dr Spencer and his colleagues said the duration of DAPT therapy should probably be based on patient preference, following a discussion of the potential risks and benefits.
