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

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

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

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.

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.

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.