Abstract 12811: Dual Antiplatelet Therapy Duration and Long-Term Risks of Adverse Outcomes After Percutaneous Coronary Intervention With Second-Generation Drug-Eluting Stents

Introduction: Randomized trials show that short dual antiplatelet (DAPT) regimens have similar adverse events to longer regimens in patients treated by percutaneous coronary intervention (PCI) using second-generation drug-eluting stents (DES2). However, these studies are underpowered for death. Hypothesis: After PCI with DES2, patients discontinuing DAPT before six months had higher risks of adverse ischemic outcomes than patients continuing DAPT for longer durations. Methods: We assessed adverse outcomes in patients having PCI between 2008-2016 in the Veterans Affairs Clinical Assessment Report and Tracking (CART) database. DAPT use was determined from the VA Pharmacy database. Outcomes after PCI were all-cause death (from the VA death index), and myocardial infarction, recurrent coronary revascularization, and major bleeding from ICD 9, ICD 10 and CPT codes in VA and Medicare/Medicaid records. Hazard ratios (HR) and 95% confidence intervals (95%CI) from Cox proportional hazards models weighted with a stabilized inverse probability of treatment weight were used to assess the risk of outcomes from stopping DAPT in 4 time intervals after PCI (1-5, 6-9, 10-12, and 13-18 months). Results: After exclusions, there were 40,871 PCIs with DES2 during the study period. Outcomes were followed for an average of 4.6 years. Compared to continuing DAPT, the risks for death were significantly higher for stopping DAPT 1-5 months after PCI (HR=2.04, 95%CI=1.82, 2.29) and stopping DAPT 6-9 months after PCI (HR=2.2, 95%CI=1.98, 2.44). There was no significant increase in death from stopping DAPT more than 10 months after PCI. Stopping DAPT 10 or more months after the index PCI associated with lower rates of myocardial infarction (HR=0.74, 95%CI=0.68, 0.81) and major bleeding (HR=0.81, 95%CI 0.73, 0.91), and lower repeat revascularization at all time periods. There was no interaction of effects with acute coronary syndrome at index PCI. Conclusion: Among Veterans having PCI with DES2, stopping DAPT less than 10 months after PCI was associated with a higher risk of death but no increased risk in myocardial infarction or major bleeding. Short DAPT regimens after PCI may increase the risk of death. Clinical trials of short DAPT duration should powered to assess this endpoint.