Just months after the MASTER DAPT trial showed that abbreviated dual-antiplatelet therapy (DAPT) lowers the risk of bleeding after stent placement in patients at high bleeding risk, a new analysis showed the favorable benefit-to-risk ratio was about the same in the subgroup who also had an acute or recent myocardial infarction.
In the new prespecified MASTER DAPT analysis, the data show that the subgroup with both an increased bleeding risk and an increased risk of ischemic events benefited much like the entire study population from a shorter DAPT duration, reported Pieter C. Smits, MD, PhD, at the Transcatheter Cardiovascular Therapeutics annual meeting, held virtually and live in Orlando.
“There was no signal towards increased ischemic risk in the abbreviated DAPT population presenting with recent acute MI,” said Dr. Smits, emphasizing the consistency of results in this “bi-risk” subgroup with objective criteria for increased risks of bleeding and ischemic events.
MASTER DAPT main results published
The main results of the MASTER DAPT trial were presented at the 2021 annual meeting of the European Society of Cardiology andrecently in the New England Journal of Medicine. The trial randomized 4,434 patients who met one or more criteria for high bleeding risk. These included age of at least 75 years, documented anemia, a clinical indication for oral anticoagulants, and previous bleeding episodes requiring hospitalization.
In the trial, all patients were maintained on DAPT for 1 month after implantation of a biodegradable-polymer, sirolimus-eluting coronary stent (Ultimaster, Terumo). At the end of the month, those randomized to abbreviated DAPT started immediately on single-agent antiplatelet therapy, while those in the standard DAPT group remained on DAPT for at least 2 additional months.
Over 1 year of follow-up, the bleeding event rate was lower in the abbreviated DAPT group (6.5% vs. 9.4%; P < .0001 for superiority). The slight increase in major ischemic events among those in the abbreviated DAPT group (6.1% vs. 5.9%) was not significantly different (P = .001 for noninferiority).
When compared on the basis of net adverse clinical events (NACE), which comprised all-case death, MI, stroke, or Bleeding Academic Research Consortium (BARC) level 3 or 5 bleeding, there was a slight advantage for abbreviated DAPT (7.5% vs. 7.7%). This did not reach significance, but it was similar (P < .001 for noninferiority), favoring the abbreviated course of DAPT because of the bleeding advantage.
Recent MI vs. no MI
In the new analysis, patients in both the abbreviated and standard DAPT group were stratified into those with no major cardiovascular event within the past 12 months and those with an acute MI or acute coronary syndrome within this time. There were somewhat more patients without a history of MI within the previous 12 months in both the abbreviated DAPT (1,381 vs. 914 patients) and standard DAPT (1,418 vs. 866) groups.
In those without a recent MI, NACE rates were nearly identical over 1-year follow-up for those who received abbreviated versus standard DAPT. In both, slightly more than 6% had a NACE event, producing a hazard ratio of 1.03 for abbreviated versus standard DAPT (P = 0.85).
For those with a recent MI, event rates began to separate within 30 days. By 1 year, NACE rates exceeded 10% in those on standard DAPT, but remained below 9% for those on abbreviated DAPT. The lower hazard ratio in the abbreviated DAPT group (HR, 0.83; P = .22) did not reach statistical significance, but it did echo the larger MASTER DAPT conclusion.
“An abbreviated DAPT strategy significantly reduced clinically relevant bleeding risk in these bi-risk patients without increasing risk of ischemic events,” reported Dr. Smits, director of interventional cardiology at Maasstad Hospital, Rotterdam, the Netherlands.