Survival penalty in patients undergoing transcatheter versus surgical aortic valve replacement: is it just a question of frailty? Insights from a large cohort with demographic matching
Authors: Boute M , De Terwangne C , De Azevedo D , Gerber B , Pasquet A , Pouleur A C , Pierard S , Maes F , Kefer J , De Kerchove L , Vancraeynest D 
Published: October 2024

Abstract

Background
Transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) are the reference treatments for aortic stenosis. Conflicting data exist on late survival results of these two techniques. While randomised controlled trials (with highly selected patients) assert the non-inferiority of TAVR, real-world data from large registries (with potential uncorrected confounders) suggest the opposite. Comparing the survival rates of SAVR and TAVR with those of a matched reference population could help circumvent potential biases of direct procedural comparisons and quantify the impact of frailty on post-operative survival.

Purpose
Our study aims to compare the 5-year overall survival rates of SAVR, non-frail TAVR, and frail TAVR patients with the survival of their demographically matched reference population.

Methods
This study included all consecutive patients undergoing either SAVR or TAVR at a tertiary hospital between January 2010 and December 2021. Each patient underwent a comprehensive geriatric assessment by an experienced geriatric team, from which a Clinical Frailty Scale (CFS) was derived using a validated classification tree. Frailty was defined as a CFS ≥ 6, in accordance with ESC guidelines. The patients were stratified into 3 subgroups: SAVR, non-frail TAVR, and frail TAVR patients. For each subgroup, a corresponding reference population was generated using national actuarial tables to ensure individual-level matching based on age, gender, and year of observation. Survival of each subgroup was then compared to its corresponding reference population over a 5-year period using standardized mortality ratios (SMR) and one-sample logrank tests.

Results
Our cohort included 1183 SAVR, 254 non-frail TAVR, and 151 frail TAVR patients, with mean ages of 74.1, 85.4, and 85.7 years, and median EuroSCORE II of 2.0%, 4.2%, and 5.4%, respectively. Survival of SAVR patients was equivalent to the reference population (80.1 vs 80.9% survival; SMR = 1.06 [0.89 – 1.25]; p = 0.454; Figure 1A). Similarly, non-frail TAVR patients also achieved survival rates comparable to those of the reference population (50.9 vs 54.0% survival; SMR = 0.94 [0.76 – 1.18]; p = 0.549; Figure 1B). However, frail TAVR patients faced a significantly reduced survival rate (41.7% vs 54.0% survival; SMR = 1.48 [1.15 – 1.90]; p &lt; 0.001; Figure 1C). The frailty of this subgroup could therefore explain a 48% increase in mortality risk compared with their reference population after 5 years.

Conclusions
Treating non-frail patients with aortic stenosis through TAVR or SAVR restores life expectancy to levels comparable with their reference population, challenging results from other real-world registries. In contrast, TAVR in frail patients is associated with worse survival, raising the question of treatment futility in this specific subgroup. Refining the selection of frail patients who may benefit from TAVR remains an important clinical challenge.