Study Compares DAPT Durations in STEMI Patients Receiving DES
November 1, 2017—Results from the DAPT STEMI were reported at TCT 2017, the 29th annual Transcatheter Cardiovascular Therapeutics scientific symposium being held October 30 to November 2 in Denver, Colorado. The trial, which is evaluating the safety of dual antiplatelet therapy (DAPT) for less than 12 months in ST-elevation myocardial infarction (STEMI), found that 6 months of DAPT was noninferior to 12 months of DAPT among patients treated with second-generation drug-eluting stents (DES).
As noted in the TCT announcement, international guidelines recommend 12 months of DAPT for STEMI patients after primary PCI with DES because of ongoing atherothrombotic risk. Although longer duration DAPT therapy reduces the risk of ischemic events, it is also associated with a higher risk of major bleeding that can sometimes be fatal. Second-generation DES have a lower stent thrombosis risk than their predecessors, questioning the need for an extended duration of DAPT.
The prospective, randomized DAPT STEMI trial was designed to evaluate whether 6 months of DAPT was noninferior to 12 months of DAPT in event free patients at 6-month follow-up after primary PCI. The study enrolled 1,100 STEMI patients who underwent primary PCI with a second-generation zotarolimus-eluting stent. Those who were event free at 6 months and agreed to continue with the study (n = 870) were randomized to single antiplatelet therapy (SAPT, n = 433) or DAPT (n = 437). Baseline and procedural characteristics were similar in both arms.
The study’s primary endpoint was a patient-oriented composite of all-cause mortality, any myocardial infarction, any revascularization, stroke, or thrombolysis in myocardial infarction (TIMI) major bleeding at 18-month follow-up after randomization (ie, 2 years after primary PCI). The primary endpoint occurred in 4.8% of the SAPT group versus 6.6% for the DAPT group (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.41–1.27; P = .26; Pnon-inferiority = .004}.
The incidences of the individual components of the primary endpoint were as follows for SAPT versus DAPT, respectively:
- Mortality: 0.7% vs 1.4% (HR, 0.51; 95% CI, 0.13–2.02; P = .33)
- Myocardial infarction: 1.8% vs 1.8% (HR, 1.02; 95% CI, 0.38–2.71; P = .97)
- Revascularization: 3% vs 3.9% (HR, 0.87; 95% CI, 0.42–1.83; P = .72)
- Stroke: 0.7% vs 0.7% (HR 1.02; 95% CI, 0.21–5.03; P = .99)
- TIMI major bleeding: 0.2% vs 0.5% (HR 0.51; 95% CI, 0.05–5.57; P = .58)
Elvin Kedhi, MD, commented in the TCT announcement, “For the first time in the modern DES era, this trial indicates that STEMI patients, similar to stable angina patients, may not benefit from prolonged DAPT therapy beyond 6 months as currently recommended. This sets the stage for further dedicated research on this important topic.” Dr. Kedhi is Head of the Interventional Cardiology and Clinical Research and Innovation at Isala Hartcentrum in Zwolle, The Netherlands.