Transapical vs. Transaxillary Access in Transcatheter Aortic Valve Implantation: Comparative Mortality and Long-Term Outcomes Using Inverse Probability of Treatment Weighting Analysis

<b>Background:</b> Transcatheter aortic valve implantation (TAVI) is the treatment of choice for symptomatic aortic stenosis in patients with moderate to high surgical risk. When transfemoral access is unsuitable, alternative routes such as transapical (TAP) or transaxillary (TAX) routes must be considered. This study compares the in-hospital mortality and clinical outcomes of TAP vs. TAX TAVI. <b>Methods:</b> We conducted a retrospective analysis of 76 patients who underwent TAP or TAX TAVI between 2018 and 2021 at our department. Inverse probability of treatment weighting (IPTW) was used to account for baseline differences. <b>Results:</b> Among 1901 TAVI procedures, a total of 76 was selected of which TAP was performed in 34.2% (<i>n</i> = 26), and TAX in 65.8% (<i>n</i> = 50) of cases. Self-expanding CoreValve Evolut R valve prostheses were used in 96% of TAX cases, while balloon-expandable Edwards SAPIEN 3 valve prostheses were exclusively implanted in TAP cases. After IPTW adjustment, baseline characteristics, including EuroSCORE II, LVEF, and NYHA class, were comparable. TAX was associated with a higher pacemaker implantation rate (22.6% vs. 0%; <i>p</i> = 0.032), while TAP had a higher incidence of late bacteremia (13.4% vs. 1.6%; <i>p</i> = 0.027) and longer hospitalization (19 [13, 28] vs. 10 [8, 21] days; <i>p</i> = 0.016). In-hospital (0% vs. 2.1%; <i>p</i> = 0.388), 30-day (3.4% vs. 3.5%; <i>p</i> = 0.957), and 3-year mortality (6.7% vs. 4.8%; <i>p</i> = 0.709) were similar. Device implantation success was 100% in both groups. Major bleeding and vascular complications were rare. Balloon predilatation was more frequent in TAX (57.6% vs. 13.3%; <i>p</i> = 0.002). Rates of mild and moderate aortic regurgitation did not differ. <b>Conclusions:</b> In patients unsuitable for transfemoral TAVI, TAP was associated with lower pacemaker rates but longer hospitalization and increased late bacteremia compared to TAX. Both approaches showed comparable safety and efficacy, emphasizing the need for individualized access selection.