Six Versus Twelve Months of Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation in ST-Elevation Myocardial Infarction - DAPT-STEMI
Contribution To Literature:
The DAPT-STEMI trial showed that among patients who remain event-free at 6 months following PPCI with a ZES for STEMI, cessation of DAPT at the 6-month mark vs. continuing for an additional 6 months (12 months total from stent implantation) is noninferior for clinical outcomes at 2 years.
The goal of the trial was to assess the safety and efficacy of 6 vs. 12 months of dual antiplatelet therapy (DAPT) in patients presenting with ST-segment elevation myocardial infarction (STEMI) and undergoing primary percutaneous coronary intervention (PPCI) with a second-generation drug-eluting stent (DES).
Patients with STEMI and undergoing PPCI with a second-generation DES (zotarolimus-eluting stent [ZES]) were randomized in a 1:1 fashion to either 6 months (n = 433) or 12 months of DAPT (n = 437).
- Total number of enrollees: 1,496
- Duration of follow-up: 1 year
- Mean patient age: 60 years
- Percentage female: 23%
- Percentage with diabetes: 14%
- Age 20-85 years
- PPCI with second-generation ZES
- Event free at 6 months (no MI, stent thrombosis, target vessel or lesion revascularization, or stroke/bleeding requiring DAPT discontinuation)
- Intolerance to aspirin, prasugrel, ticagrelor, heparin, bivalirudin, zotarolimus, or everolimus
- Planned elective surgical procedure necessitating interruption of DAPT during the first 6 months after the procedure
- Need for oral anticoagulation
- History of stent thrombosis
- DES in main left coronary artery
- Active bleeding, known bleeding diathesis, or known coagulopathy
- Oral anticoagulant therapy with Coumadin derivative
- Malignancies or other comorbidity
Other salient features/characteristics:
- Prior MI: 5%
- P2Y12 inhibitor at start of trial: clopidogrel: 42%, prasugrel: 30%, ticagrelor 29%
- Infarct vessel: left anterior descending: 41%, right coronary artery: 41%
- Average number of treated vessels: 1.08
- Total stented length: 29 mm
The primary outcome, all-cause mortality, MI, revascularization, stroke, and TIMI major bleeding at 18 months for 6-month vs. 12-month DAPT, was 4.8% vs. 6.6%, p for noninferiority = 0.004, p for superiority = 0.26.
- All-cause mortality: 0.7% vs. 1.4%, p = 0.33
- MI: 1.8% vs. 1.8%, p = 0.97
- TIMI major bleeding: 0.2% vs. 0.5%, p = 0.58
Secondary outcomes for 6-month vs. 12-month DAPT:
- Stent thrombosis: 0.7% vs. 0.9%, p = 0.72
- Target lesion failure: 1.2% vs. 1.8%, p = 0.42
The results of this trial indicate that among patients who remained event free at 6 months following PPCI with a ZES for STEMI, cessation of DAPT at the 6-month mark vs. continuing for an additional 6 months (12 months total from stent implantation) is noninferior for clinical outcomes at 2 years. The trial was underpowered to assess individual safety endpoints. These are thought-provoking results, and while they may not change practice or guidelines immediately, they indicate the need for additional clinical trials in this area. The most recent American College of Cardiology/American Heart Association DAPT guidelines indicate that a 6-month duration may be reasonable among patients undergoing PCI for stable angina.
Presented by Dr. Elvin Kedhi at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2017), Denver, CO, November 1, 2017.
Keywords: Acute Coronary Syndrome, Adenosine, Angina, Stable, Coronary Vessels, Drug-Eluting Stents, Myocardial Infarction, Myocardial Revascularization, Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Purinergic P2Y Receptor Antagonists, Sirolimus, Stents, Stroke, Thrombosis, TCT17, Transcatheter Cardiovascular Therapeutics
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