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For high-bleeding risk patients, a shorter duration of dual antiplatelet therapy (DAPT) appeared just as safe for those getting novel stent after acute myocardial infarction (MI) in the MASTER-DAPT trial.

Stopping anticoagulant at 30 days didn't yield significantly different outcomes whether patients had a prior MI or not, reported Pieter C. Smits, MD, PhD, of Maasstad Hospital in Rotterdam, the Netherlands, at the Transcatheter Cardiovascular Therapeutics (TCT) meeting held in Orlando, Florida, and broadcast online.

The composite of all-cause mortality, MI, stroke, and clinically-relevant bleeding by BARC 3 or 5 criteria came out similar between the abbreviated group and those getting the anticoagulant in their DAPT regimen for 2 months or longer (P=0.30 for interaction for both groups):

• With prior MI: HR 0.83 (95% CI 0.61-1.12)
• Without MI in the prior 12 months: HR 1.03 (95% CI 0.77-1.38)

Ischemic events alone (all-cause mortality, MI, and stroke) showed the same pattern, with no significant difference between DAPT duration for either group and no interaction by prior MI.

As expected, there were fewer clinically relevant bleeding events by BARC 2, 3, or 5 criteria in both MI and no-MI groups with the shorter dual regimen (HR 0.65 and 0.71, respectively, P=0.01 for both), which was driven by the non-clinically relevant bleeds.

"One of the concerns people have had is exactly what has been addressed here in this subgroup analysis: patients with prior MI in whom not only is bleeding risk high but ischemic risk is high. Is the benefit in reducing bleeding offset by an increase in stent thrombosis or other ischemic outcomes? And the answer...is really clearly 'no,'" said TCT session discussant Philippe Gabriel Steg, MD, of Hôpital Bichat in Paris. He called the findings "good news."

However, the findings will likely "raise a lot of eyebrows," predicted TCT press conference moderator Ajay Kirtane, MD, of NewYork-Presbyterian/Columbia University Irving Medical Center in New York City. He noted the discrepancy from the STOPDAPT-2 ACS trial in which 1 month DAPT didn't hold any advantage for ischemic events but did raise the MI rate.

One question raised by panelists at the press conference, and at the late-breaking clinical trial TCT session, was generalizability to other stent types.

The prespecified secondary analysis of the trial, which had been prospectively stratified by MI within the prior 12 months, included 4,579 high bleeding risk patients stented with the thin-strut, biodegradable polymer stent, which is approved in Europe but not the U.S. Participants were randomized at 30 days after stenting if they were free at that point from cardiac and cerebral ischemic events and active bleeding.

Session panelist Anibal A. Damonte, MD, of the Instituto Cardiovascular de Rosario in Santa Fe, Argentina, argued that the findings could be extrapolated to any similar current-generation stent platform.

"The question of whether it's a class effect or whether this is applicable to all new generation drug eluting stents is hard to answer," Smits said, although "we don't see that much difference nowadays between new generation stents and outcome on specific device-related endpoints."

Abbreviated DAPT in the trial comprised immediate discontinuation of the anticoagulant in the regimen at randomization. Just a single antiplatelet was continued out to 1 year, or 5 months if an oral anticoagulant was indicated.

The non-abbreviated DAPT group got the full regimen for at least 2 months after randomization, or 5 months if there was an oral anticoagulation indication. After that point, antiplatelet monotherapy was continued out to 1 year.

DAPT duration came out a median 34 days in the abbreviated group compared with 193 days among controls.

Altogether 1,780 patients had an MI in the prior year, of whom 95% were acute at the time of the baseline procedure. As expected, the prior MI group was more likely to continue P2Y12 inhibitors than aspirin after stopping anticoagulation.

While post hoc subgroup analyses haven't been done for very complex cases, the trial included a fairly all-comer population, Smits said.

"In high bleeding risk patients, it's probably wise to shorten your DAPT as short as possible, which is safe, and then continue with a drug you might think is effective in preventing ischemic events, and is not causing too much bleeding," he concluded. "We see from other studies that prolonging your DAPT beyond 12 months in high bleeding risk patients will only give an excess bleeding, so for those patients I would definitely not prolong DAPT."

The that has looked at DAPT duration showed it's not just only about the stent, but also reducing residual ischemic risk, Kirtane noted, although bleeding risk has to be dealt with and maybe the answer could be dropping aspirin too.

It's important to do risk-benefit analysis, said TCT press conference panelist Ruby Satpathy, MD, of Baptist Heart Specialists in Jacksonville, Florida.

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