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DENVER -- Just 6 months of dual antiplatelet therapy (DAPT) may be sufficient for ST-segment elevation MI (STEMI) patients getting second-generation drug-eluting stents (DES), according to the DAPT-STEMI trial.

Whether patients got 6 or 12 months of DAPT made no difference in event rates 24 months after primary percutaneous coronary intervention (PCI), as combined rates of all-cause mortality, MI, any revascularization, stroke, and TIMI major bleeding were not statistically significant between groups (4.8% for short DAPT versus 6.6% for longer DAPT, HR 0.73, 95% CI 0.41-1.27, P_{non-inferiority}=0.004).

Short and long DAPT were associated with similar odds of combined all-cause mortality, MI, stroke, stent thrombosis, or TIMI major bleeding (3.2% versus 4.3%, HR 0.75, 95% CI 0.37-1.49). Individual endpoints showed no difference between groups either, according to Elvin Kedhi, MD, PhD, of Isala Hartcentrum in the Netherlands, who presented results of the trial at the meeting here.

"This trial, for the first time showed that, in the modern-DES era, event-free STEMI patients do not benefit from a prolonged DAPT beyond 6 months as currently recommended, and sets the stage for further dedicated research in this important topic," Kedhi told the audience.

Stents are safer now, and clinicians are treating atherosclerosis better generally, commented press conference moderator Gary Mintz, MD, Chief Medical Officer of the Cardiovascular Research Foundation in New York, who agreed that the tide is shifting toward shorter DAPT.

"The need for DAPT has decreased. Anybody who's a clinician taking care of patients with drug-induced bleeding after stent [placement] knows it's not trivial," he continued.

The Resolute Integrity zotarolimus-eluting stent was the device of choice in DAPT-STEMI.

The European trial was designed such that all participants were on DAPT for the first 6 months after PCI, then randomized to another 6 months of DAPT (followed by aspirin for the subsequent year) or just aspirin for the next 18 months. Randomization at the 6-month mark excluded those who had bled or already had adverse events, as well as those who started oral anticoagulation or received further revascularization by then.

After randomization, the two groups in DAPT-STEMI were well-balanced at baseline and shared similar procedural characteristics.

Notably, the investigators needed 1,000 patients for 85% power in demonstrating non-inferiority of short DAPT. Even after enrolling 1,100 to anticipate patient loss, Kedhi's group only ended up with 861 patients for their final analysis.

Kedhi explained why at a press conference:

"We have previously had been hammered into us the concept that DAPT should be taken for 12 months and if you don't do this, then you are at very high risk of MI or death. When we started this trial in 2011 (really it was 2012), having to change this mentality was almost impossible. To be honest, we wanted to [test for] 3-month DAPT and that was impossible so we took it to 6 months. We were trying to convince physicians who said 'Are you crazy?'"

"The change in mentality will take time," he concluded.

A larger trial is underway to help in that regard, the Onyx ONE trial randomizing 2,000 patients to the Resolute Onyx DES or the BioFreedom drug-coated stent, with both groups taking just 1 month of DAPT afterward.

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