External Validation of DAPT Score
What is the utility of the DAPT (Dual Antiplatelet Therapy study) score for stratifying the ischemic and bleeding risks and for guiding the duration of DAPT after drug-eluting stent (DES) implantation in a large pooled cohort from three Japanese percutaneous coronary intervention (PCI) studies?
The investigators compared risks for ischemic and bleeding events from 13 to 36 months after PCI between patients with a DAPT score ≥2 (high-DS) and DAPT score <2 (low-DS) in a pooled cohort of three studies conducted in Japan (the CREDO [Coronary REvascularization Demonstrating Outcome Study] Kyoto registry cohort-2, RESET [Randomized Evaluation of Sirolimus-Eluting vs. Everolimus-Eluting Stent Trial], and NEXT [NOBORI Biolimus-Eluting vs. XIENCE/PROMUS Everolimus-Eluting Stent Trial). The primary ischemic endpoint was defined as a composite of myocardial infarction (MI) (defined by the ARTS [Arterial Revascularization Therapies Study] in the CREDO-Kyoto registry cohort-2 and by the ARC [Academic Research Consortium] criteria in RESET and NEXT trials) and definite/probable stent thrombosis (ST) (defined by the ARC criteria). The primary bleeding endpoint was defined as moderate or severe bleeding by the GUSTO (Global Utilization of Streptokinase and Tissue plasminogen activator for Occluded coronary arteries) classification. Cumulative incidences of events were estimated by the Kaplan-Meier method, and the differences were assessed by the log-rank test.
Among 12,223 patients receiving DES who were free from ischemic or bleeding events at 13 months after PCI, 3,944 had high-DS and 8,279 had low-DS. The cumulative incidence of the primary ischemic endpoint (MI/ST) was significantly higher in high-DS than in low-DS (1.5% vs. 0.9%, p = 0.002), while the cumulative incidence of the primary bleeding endpoint (GUSTO moderate/severe) tended to be lower in high-DS than in low-DS (2.1% vs. 2.7%, p = 0.07). The cumulative incidences of cardiac death, MI, and ST were also significantly higher in high-DS than in low-DS (2.0% vs. 1.4%, p = 0.03; 1.5% vs. 0.8%, p = 0.002; 0.7% vs. 0.3%, p < 0.001, respectively), while the cumulative incidences of noncardiac death and GUSTO severe bleeding were significantly lower in high-DS than in low-DS (2.4% vs. 3.9%, p < 0.001; 1.0% vs. 1.6%, p = 0.03, respectively).
The authors concluded that the DAPT score successfully stratified ischemic and bleeding risks.
This pooled cohort study reports that the DAPT score successfully stratified the ischemic and bleeding risks beyond 1 year after DES-PCI, but the event rate of MI and ST was remarkably low even in patients with a high-DS. Furthermore, on-DAPT patients at 13 months as compared with off-DAPT tended to be at a lower risk for ischemic events in high-DS and at a higher risk for bleeding events in low-DS, although the differences were not statistically significant. Additional studies are indicated to evaluate the real-world utility of prolonged DAPT guided by the DAPT score, given very low event rates even in patients with high-DS.
Keywords: Acute Coronary Syndrome, Drug-Eluting Stents, Hemorrhage, Myocardial Infarction, Myocardial Ischemia, Outcome Assessment (Health Care), Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Sirolimus, Thrombosis
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