SMART-DATE: Myocardial Infarction Risk Higher with Six-Month Versus Twelve-Month DAPT

Six months of dual antiplatelet therapy (DAPT) was noninferior to 12 months or longer of DAPT for preventing major adverse cardiac and cerebrovascular events (MACCE) in the open label, randomized SMART-DATE trial. But, the risk of myocardial infarction (MI) was significantly increased after drug-eluting stent (DES) implantation in patients with acute coronary syndrome (ACS). The results were presented by Hyeon-Cheol Gwon, MD, PhD, on Monday, March 12 in a Late-Breaking Clinical Trial session at ACC.18 in Orlando, FL., and simultaneously published in The Lancet.

A total of 2,712 patients with ACS were randomized to 6-month DAPT (n=1,357) or 12-month DAPT (n=1,355) with aspirin and clopidogrel following DES implantation. The primary endpoint was MACCE –  the composite of all-cause death, MI or stroke at 18 months after the index procedure. Safety was assessed by the rate of BARC type 2 to 5 bleeding.

At 18 months of follow-up, at least one MACCE occurred in 4.7 percent of the 6-month DAPT group and in 4.2 percent of the 12-month DAPT group, demonstrating the noninferiority of 6-month DAPT. Rates of all-cause death did not differ between the 6-month and 12-month DAPT groups (2.6 vs. 2.9 percent). The risk of MI was a significant 2.4-fold higher in the 6-month DAPT group versus the 12-month DAPT group (1.8 vs. 0.8 percent).

In a landmark analysis, the risk of MACCE between six and 18 months tended to be higher in the 6-month DAPT group than in the 12-month DAPT group, with a significant increase in MI in the 6-month DAPT group.

Rates of stent thrombosis were not significantly different in the 6-month DAPT group versus the 12-month DAPT group (1.1 vs. 0.7 percent). The rate of BARC type 2 to 5 bleeding was 2.7 percent in the 6-month DAPT group compared with 3.9 percent in the 12-month DAPT group, which was not statistically significant.

"Based on our findings, we cannot say that short-term DAPT is safe in patients with ACS who have received drug-eluting stents," said Gwon. "We conclude that current guidelines that recommend  prolonged DAPT in patients with ACS who are not at excessive risk for bleeding should continue to be followed."

Keywords: ACC18, ACC Annual Scientific Session, Angiography, Drug-Eluting Stents, Acute Coronary Syndrome, Confidence Intervals, Percutaneous Coronary Intervention, Myocardial Infarction, Hemorrhage, Stroke, Diabetes Mellitus, Type 2

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