Background: The dual-antiplatelet therapy (DAPT) score was developed to identify patients more likely to derive harm (score <2) or benefit (score ≥2) from prolonged DAPT after percutaneous coronary intervention (PCI).
Objective: To evaluate the safety and efficacy of DAPT duration according to DAPT score.
Design: Retrospective assessment of DAPT score-guided treatment duration in a randomized clinical trial. (ClinicalTrials.gov: NCT00611286).
Setting: PCI patients.
Patients: 1970 patients undergoing PCI.
Intervention: DAPT (aspirin and clopidogrel) for 24 versus 6 months.
Measurements: Primary efficacy outcomes were death, myocardial infarction, or cerebrovascular accident. The primary safety outcome was type 3 or 5 bleeding according to the Bleeding Academic Research Consortium definition. Outcomes were assessed between 6 and 24 months.
Results: 884 patients (44.9%) had a DAPT score of at least 2, and 1086 (55.1%) had a score less than 2. The reduction in the primary efficacy outcome with 24- versus 6-month DAPT was greater in patients with high scores (risk difference [RD] for score ≥2, -2.05 percentage points [95% CI, -5.04 to 0.95 percentage points]; RD for score <2, 2.91 percentage points [CI, -0.43 to 6.25 percentage points]; P = 0.030). However, the difference by score for the primary efficacy outcome varied by stent type; prolonged DAPT with high scores was effective only in patients receiving paclitaxel-eluting stents (RD, -7.55 percentage points [CI, -12.85 to -2.25 percentage points]). The increase in the primary safety outcome with 24- versus 6-month DAPT was greater in patients with low scores (RD for score ≥2, 0.20 percentage point [CI, -1.20 to 1.60 percentage points]; RD for score <2, 2.58 percentage points [CI, 0.71 to 4.46 percentage points]; P = 0.046).
Limitation: Retrospective calculation of the DAPT score.
Conclusion: Prolonged DAPT resulted in harm in patients with low DAPT scores undergoing PCI but reduced risk for ischemic events in patients with high scores receiving paclitaxel-eluting stents. Whether prolonged DAPT benefits patients with high scores treated with contemporary drug-eluting stents requires further study.
Primary funding source: None.