Efficacy and Safety of Antiplatelet Therapy After Endovascular Aortic Repair: A Target Trial Emulation

BACKGROUND: The optimal antiplatelet regimen after standard endovascular aneurysm repair (EVAR) in patients without atherosclerotic cardiovascular disease remains uncertain. Clinical guidelines offer limited recommendations, and data specific to this population are sparse. This study aimed to compare the efficacy and safety of single versus dual antiplatelet therapy (DAPT) in patients undergoing standard EVAR for abdominal aortic aneurysms without established atherosclerotic cardiovascular disease. METHODS: This study emulated a target trial using the Korean National Health Insurance Service database, which includes the entire Korean population. We identified all patients who underwent standard EVAR between January 2003 and September 2023 and excluded those with atherosclerotic cardiovascular disease or no antiplatelet therapy. Patients were categorized by discharge medication into single antiplatelet therapy or DAPT groups. The primary cardiovascular efficacy end point was major adverse cardiac and cerebrovascular events (all-cause death, myocardial infarction, or ischemic stroke). The EVAR-specific efficacy end point was abdominal aortic aneurysm reintervention or surgery. The safety end point was major or clinically relevant nonmajor bleeding. Inverse probability treatment weighting was applied to adjust baseline differences. RESULTS: Among 8325 patients, 4162 (50.0%) received single antiplatelet therapy (80.6% aspirin, 19.4% clopidogrel), and 4163 (50.0%) received DAPT (aspirin plus clopidogrel). There were no significant differences between single antiplatelet therapy and DAPT in the risk of major adverse cardiac and cerebrovascular events (inverse probability treatment weighting-hazard ratio [HR], 1.07 [95% CI, 0.93-1.22]) or abdominal aortic aneurysm reintervention/surgery (inverse probability treatment weighting-HR, 1.07 [95% CI, 0.92-1.24]). However, DAPT was associated with a higher risk of major or clinically relevant nonmajor bleeding (inverse probability treatment weighting-HR, 1.20 [95% CI, 1.02-1.41]). CONCLUSIONS: In patients without atherosclerotic cardiovascular disease undergoing standard EVAR, DAPT did not confer cardiovascular or procedural benefit but was associated with increased bleeding. Single antiplatelet therapy may represent a safer and equally effective antiplatelet strategy in this population. REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT06876727.