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 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 and published recently 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 Smits, director of interventional cardiology at Maasstad Hospital, Rotterdam, the Netherlands.
No Difference in NACE Components
In fact, when the components of NACE were evaluated individually in the subgroup of patients with prior MI, both stroke (HR, 0.47; P = .16) and all-cause death (HR, 0.78; P = .28), although not significant, numerically favored abbreviated DAPT.
There was no difference between abbreviated and standard DAPT for risk of MI at 1 year (HR, 1.03; P = .92).
As in the overall MASTER DAPT results, bleeding risk (BARC 2, 3, or 5 bleeding) was significantly reduced in the substudy among those with a recent prior MI (P = .013) or those with no MI in the prior 12 months (P = .01).
In MASTER DAPT, which was an open-label study that randomized participants in 30 countries, all patients received one type of drug-eluting stent. While Smits conceded that it is not clear whether the conclusions about abbreviated DAPT can be extrapolated to other stents, he noted that recent long-term outcomes for modern drug-eluting coronary stents have been similar, suggesting these results might be more broadly applicable.
According to Smit, the consistency of this subgroup analysis with the previously published MASTER DAPT study is mutually reinforcing for a role of abbreviated DAPT in patients at high bleeding risk. Other experts agreed.
“One of the concerns that people have had is exactly what has been addressed here in this subgroup analysis. These are the patients that are not only bleeding-risk high but ischemic-risk high. The question was whether the benefit of reducing bleeding risk is offset by increasing stent thrombosis or other ischemic event outcomes, and the answer from the analysis is really clearly no,” said Philippe Gabriel Steg, MD, chief, department of cardiology, Hôpital Bichat, Paris, at the meeting, sponsored by the Cardiovascular Research Foundation.
Smits reports financial relationships with Abiomed, Abbott Vascular, Daiichi-Sankyo, Microport, Opsense, and Terumo Medical. Steg reports financial relationships with Amgen, AstraZeneca, Bayer, Boehringer-Ingelheim, Bristol Myers Squibb, Idorsia, Merck, Novartis, Regeneron, and Sanofi-Aventis.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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