Single Versus Dual Antiplatelet Therapy After Transcatheter Aortic Valve Implantation in Patients Without Chronic...

Background: The optimal antiplatelet strategy after transcatheter aortic valve implantation (TAVI) in patients who do not require long-term oral anticoagulation remains debated. Randomized trial evidence supports single antiplatelet therapy (SAPT) over dual antiplatelet therapy (DAPT), yet real-world practice patterns and the magnitude of benefit in contemporary TAVI populations remain heterogeneous. Methods: We analyzed consecutive patients undergoing TAVI at a single tertiary center between April 2009 and April 2023 who were discharged on an antiplatelet regimen only. Patients on chronic oral anticoagulation were excluded. The exposure was defined by the discharge regimen (SAPT vs. DAPT), treated as a time-varying variable with person-time split at the documented date of any regimen change. The pre-specified efficacy endpoint was ischemic major adverse cardiovascular events (iMACE: death, stroke, or myocardial infarction); net adverse clinical events (NACEs) added major bleeding. The primary analysis was a time-varying Cox model adjusted for baseline variables. Sensitivity analyses included an intention-to-treat Cox model, a 6-month landmark Cox model, and an inverse-probability-of-treatment-weighted (IPTW) time-varying Cox model. Results: Of 662 eligible patients, 147 (22.2%) were discharged on SAPT and 515 (77.8%) on DAPT. Median follow-up was 34 months (IQR 14-52). During follow-up, 141 iMACE and 146 NACEs occurred. In the primary time-varying Cox model, the adjusted hazard ratio for DAPT versus SAPT was 1.28 (95% CI 0.81-2.04; p = 0.292) for iMACE and 0.71 (95% CI 0.44-1.14; p = 0.159) for NACE. None of the sensitivity models demonstrated a statistically significant difference between groups. Major bleeding was rare (six events; two SAPT, four DAPT). The 30-day landmark analysis showed no signal of an effect of regimen on late stroke (HR 1.12, 95% CI 0.39-3.12). Conclusions: In a contemporary real-world TAVI cohort, no statistically significant difference between SAPT and DAPT was observed for ischemic or net adverse clinical events. These findings demonstrate no ischemic disadvantage of SAPT compared with DAPT in real-world practice and are consistent with the randomized evidence base supporting SAPT as a reasonable default antiplatelet strategy after TAVI in patients without another antithrombotic indication. The bleeding endpoint was underpowered, and the expected bleeding advantage of SAPT could not be independently evaluated in this cohort.