Flow-gradient Phenotypes and Functional Recovery After Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis: A COMPARE-TAVI 1 Sub-study

BACKGROUNDPatients with severe aortic stenosis (AS) exhibit heterogeneous flow-gradient hemodynamics and ventricular remodeling, which may influence symptomatic, functional, and structural responses to transcatheter aortic valve implantation (TAVI). Thus, we evaluated differences in functional recovery and reverse remodeling after transfemoral TAVI across flow-gradient phenotypes. METHODSIn this sub-study of the COMPARE-TAVI 1 trial, 975 patients undergoing transfemoral TAVI were classified as classical low-flow low-gradient (cLFLG, 9.1%), paradoxical low-flow low-gradient (pLFLG, 7.7%), low-flow high-gradient (24.7%), normal-flow low-gradient (NFLG, 13.0%), and normal-flow high-gradient (45.4%). The primary functional outcome was longitudinal change in six-minute walk test distance (6MWTD) from baseline to 1 year follow-up. Secondary endpoints included changes in NYHA functional class and reverse remodeling from baseline to 1 year follow-up along with the incidence and risk of all-cause death and a composite MACE-endpoint. RESULTSMean 6MWTD increased by 59{+/-}4 meters at 1-month (p=0.000) with no additional improvement at 1-year, but with heterogeneity between groups (p=0.000). Improvements among NFLG, cLFLG and low-flow high-gradient AS were comparable with normal-flow high-gradient AS, while pLFLG AS exhibited significantly increments at 1-year (-28{+/-}15 meters, p=0.007). Patients with NFLG, cLFLG and pLFLG were more symptomatic at baseline (NYHA [≥]III: 40.5%, 57.3% and 50.6%, respectively, p=0.000). NYHA improved in all groups at 1-year follow-up (p=0.000), although persistent symptoms at 1-year were most frequent in pLFLG (NYHA [≥]II; 38.7%, p=0.012). Reverse remodeling was also comparable between normal-flow high-gradient AS and NFLG, cLFLG, and low-flow high-gradient AS, respectively, but attenuated in pLFLG AS in both unadjusted and adjusted analyses. No differences were observed in the incidence and risk of all-cause death or the composite MACE-endpoint. CONCLUSIONTAVI associates with functional recovery across all flow-gradient phenotypes, although with heterogeneous responses. Patients with NFLG showed comparable functional recovery and reverse remodeling at 1-year follow-up compared with normal-flow high-gradient AS, whereas pLFLG demonstrated attenuated benefits across all parameters.