E-33 | Impact of Single Antiplatelet Monotherapy Versus Dual Antiplatelet Therapy on 2-Year Outcomes Following Transcatheter Aortic Valve Replacement

In patients undergoing transcatheter aortic valve replacement (TAVR) who do not have an indication for long-term oral anticoagulation, current recommendations for antithrombotic therapy favor use of single antiplatelet monotherapy (SAPT) over dual antiplatelet therapy (DAPT). Recent studies have demonstrated increased bleeding events in DAPT versus SAPT patients with an equivalent risk in ischemic outcomes. We assessed 2-year clinical outcomes in 1,163 TAVR patients who were discharged alive and were treated either with SAPT (n=361) or DAPT (n=802). SAPT included monotherapy with either aspirin alone (n=315) or a thienopyridine alone (n=46). Propensity matching was used to eliminate confounders. Matched SAPT (n=349) and DAPT (n=589) patients had no differences in age (81.6±8.0 vs 81.3±8.2 years, p=0.288) or female gender (51.3 vs 45.8%, p=0.106). SAPT and DAPT cohorts had similar baseline demographics, risk factors and comorbidities, including history of prior myocardial infarction (16.9 vs 19.5%, p=0.319), prior PCI (15.5 vs 20.0%, p=0.081) and pre-existing atrial fibrillation (14.9 vs 12.4%, p=0.489). STS Risk Score (7.9±6.1 vs 8.2±6.1, p=0.261), use of femoral versus alternative vascular access, and TAVR balloon type did not differ between cohorts. In hospital outcomes (ischemic stroke (0.9 vs 1.1%, p=0.889), major vascular complications (2.0 vs 2.0%, p=0.973), composite bleeding (4.0 vs 3.4%, p=0.626), pacemaker implantation (11.5 vs 14.4%, p=9.196) were similar for the two cohorts. Kaplan-Meier analysis demonstrated that SAPT patients had all-cause increased mortality at 2-years (log-rank chi-square 8.2, p=0.004). Other adverse 2-year outcomes are summarized below.Tabled 12-Year Adverse EventsSAPTDAPTP valueStroke11 (3.2%)15 (2.5%)0.585Myocardial Infarction1 (0.3%)2 (0.3%)0.889Major Bleeding Event1 (0.3%)5 (0.8%)0.421Subclinical Leaflet Thrombosis3 (0.9%)4 (0.7%)0.756 Open table in a new tab In this single-center retrospective study, SAPT in comparison to DAPT is associated with increased all-cause mortality with no cohort differences in stroke, myocardial infarction, major bleeding events or subclinical leaflet thrombosis at 2-years.