Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis: results from an intermediate risk propensity-matched population of the Italian OBSERVANT study.

Background: Few studies have yielded information on comparative effectiveness of transcatheter aortic valve implantation (TAVI) versus surgical aortic valve replacement (SAVR) procedures in a real-world setting. The aim of this analysis is to describe procedural and post-procedural outcomes in a TAVI/SAVR intermediate risk propensity-matched population.

Methods: OBSERVANT is an observational prospective multicenter cohort study, enrolling AS patients undergoing SAVR or TAVI. Propensity score method was applied to analyze procedural and post-procedural outcomes. Pairs of patients with the same probability score were matched (caliper matching).

Results: The unadjusted enrolled population (N=2108) comprises 1383 SAVR patients, 602 transarterial-TAVI patients and 123 transapical-TAVI patients. Matched population comprised a total of 266 patients (133 patients for each group). A relatively low risk population was selected (mean logistic EuroSCORE 9.4 ± 10.4% vs 8.9 ± 9.5%, SAVR vs TAVI; p=0.650). Thirty-day mortality was 3.8% for both SAVR and TAVI (p=1.000). The incidence of stroke (1.5% SAVR and 0.0% TAVI; p=0.156) and myocardial infarction (0.8% SAVR and 0.8% TAVI; p=1.000) was not statistically different between groups, whereas a higher requirement for blood transfusion was reported across the surgical cohort (49.6% vs 36.1%; p=0.026). A higher incidence of major vascular damage (5.3% vs. 0.0%; p=0.007) and pacemaker implantation(0.8% vs 12.0%; p=0.001) were reported in the TAVI group.

Conclusions: Patients undergoing transcatheter and surgical treatment of severe aortic stenosis are still extremely distinct populations. In the relatively low-risk propensity-matched population analyzed, despite similar procedural and 30-day mortality, SAVR was associated with a higher risk for blood transfusion, whereas TAVI showed a significantly increased rate of vascular damage, permanent AV block and residual aortic valve regurgitation.