Long-term outcomes of self-expanding versus balloon-expandable transcatheter aortic valves: Insights from the OBSERVANT study

Objectives: To compare clinical outcomes of balloon-expandable (BE) and self-expanding (SE) transcatheter aortic valves (TAVs) up to 5 years.

Background: To date, no robust, comparative data of BE and SE TAVs at long-term are available.

Methods: We considered a total of 1,440 patients enrolled in the multicenter OBSERVANT study and undergoing transfemoral transcatheter aortic valve implantation (TF-TAVI) with either supra-annular SE (n = 830, 57.6%) and intra-annular BE (n = 610, 42.4%) valves. Clinical outcomes of the two groups were compared after adjustment using inverse probability of treatment weighting (IPTW) and confirmed by sensitivity analysis with propensity score matching.

Results: Patients receiving SE valve showed a higher all-cause mortality at 5 years (Kaplan-Meier estimates 52.3% vs. 47.7%; Hazard ratio [HR] 1.18, 95% confidence interval [CI] 1.01-1.38, p = .04). Landmark analyses showed that there was a not statistically significant reversal of risk excess against the BE group starting from 3 years after TAVI (3-5 years HR 0.97, 95% CI 0.76-1.25, p = .86). Post-procedural, moderate/severe paravalvular regurgitation (PVR)(HR 1.46, 95% CI 1.14-1.87; p < .01) and acute kidney injury (AKI)(HR 3.89, 95% CI 2.47-6.38; p < .01) showed to be independent predictors of 5-year all-cause mortality in multivariable analysis.

Conclusions: Considering the intrinsic limitations of the OBSERVANT study, we found that patients undergoing TF-TAVI with a supra-annular SE valve had a higher all-cause mortality compared to those receiving an intra-annular BE valve at 5 years. A late catch up phenomenon of patients receiving the BE valve was observed beyond 3 years. Post-procedural moderate/severe PVR seems to play a crucial role in determining this finding. Comparative studies of new generation devices with longer follow-up are needed to evaluate the benefit of each specific TAV type.