HMN 2025: How Trial findings support 3 months of blood thinners, rather than 12 months, in patients after myocardial infarction

Three months of dual antiplatelet therapy (DAPT) was associated with signals suggesting improved survival and lower bleeding risk than 12 months of DAPT, in a real-world all-comer population of patients with myocardial infarction (MI), according to late-breaking research presented in a Hot Line session at the ESC Congress 2025.

“In patients after a heart attack, the first 1–3 months is associated with the highest risk of recurrent events. Evidence indicates that compared to the guideline recommendations of 12 months of DAPT, shorter DAPT durations have equivalent efficacy in reducing recurrent events, with a lower risk of major bleeding and a trend toward lower death rates in MI patients treated with stents,” explained Principal Investigator, Professor David Newby from the University of Edinburgh, UK.

“We therefore conducted the DUAL-ACS trial to investigate the effect of three months vs. 12 months of DAPT in a real-world population of patients with MI, treated with stents, bypass grafting or medical therapy alone.”

DUAL-ACS was an open-label, investigator-initiated, randomized trial. The trial was initially conducted in Scotland. However, the COVID-19 pandemic had an adverse impact on recruitment. Patients from England and New Zealand were then recruited. Eligible patients had had a type 1 MI within 12 weeks and required DAPT (aspirin and a P2Y12 inhibitor) in the opinion of the attending clinician.

Patients were randomized 1:1 to either three or 12 months of DAPT. All patients were managed according to local clinical practice. Hospital admission statistics and mortality were obtained through routinely collected health records data. The primary endpoint was all-cause mortality.

A total of 5,052 patients were randomized who had a mean age of 63 years and 27% were female. Following the index admission, 23% received medical management only, 70% underwent percutaneous coronary intervention and 6% had coronary artery bypass graft surgery.

After follow-up of 15 months, the primary endpoint of all-cause mortality occurred in 2.7% of patients in the three-month DAPT group and 3.4% of patients in the 12-month DAPT group (hazard ratio [HR] 0.78; 95% confidence interval [CI] 0.57 to 1.07; p=0.1232) with no difference in cardiovascular death or non-fatal MI (HR 1.04; 95% CI 0.87 to 1.26; p=0.6149).

Fatal and non-fatal major bleeding occurred in 3.2% of patients in the three-month DAPT group and 4.0% of patients in the 12-month DAPT group (HR 0.78; 95% CI 0.58 to 1.06; p=0.0977).

In conclusion, Professor Newby said, “This all-comer real-world trial recruited only 30% of the planned participants and was unable to address the primary question definitively. However, there was no evidence that DAPT given for 12 months conferred any additional benefit.

“Indeed, the trends for lower mortality and bleeding risk with three months of DAPT are consistent with prior meta-analyses and suggest that limiting DAPT duration to three months may be safer in a real-world contemporary population.”

The content is provided for information purposes only.