Incidence and Sequelae of Prosthesis-Patient Mismatch in Transcatheter Versus Surgical Valve Replacement in High-Risk Patients With Severe Aortic Stenosis

Abstract

BACKGROUND Little is known about the incidence of prosthesis-patient mismatch (PPM) and its impact on outcomes after transcatheter aortic valve replacement (TAVR). OBJECTIVES The objectives of this study were: 1) to compare the incidence of PPM in the transcatheter and surgical aortic valve replacement (SAVR) randomized (RCT) arms of the PARTNER-I trial Cohort A; and 2) to assess the impact of PPM on regression of left ventricular (LV) hypertrophy and mortality in these 2 arms and in the TAVR nonrandomized continued access (NRCA) Registry cohort. METHODS The PARTNER trial Cohort A randomized patients 1:1 to TAVR or bioprosthetic SAVR. Postoperative PPM was defined as absent if indexed effective orifice area >0.85, moderate ≥0.65 but ≤0.85, or severe <0.65 cm2/m2. LV mass regression and mortality were analyzed using the SAVR-RCT (n = 270), TAVR-RCT (n = 304) and TAVR-NRCA (n = 1637) cohorts. RESULTS Incidence of PPM was 60.0% (severe: 28.1%) in SAVR-RCT versus 46.4% (severe: 19.7%) in TAVR-RCT (p < 0.001) and 43.8% (severe: 13.6%) in TAVR-NRCA. In patients with aortic annulus diameter < 20 mm, severe PPM developed in 33.7% undergoing SAVR compared to 19.0% undergoing TAVR (p = 0.002). PPM was an independent predictor of less LV mass regression at 1 year in SAVR-RCT (p = 0.017) and TAVR-NRCA (p = 0.012) but not in TAVRRCT (p = 0.35). Severe PPM was an independent predictor of 2-year mortality in SAVR-RCT (hazard ratio [HR]: 1.78; p = 0.041) but not in TAVR-RCT (HR: 0.58; p = 0.11). In the TAVRNRCA, severe PPM was not a predictor of 1-year mortality in the whole cohort (HR: 1.05; p = 0.60) but did independently predict mortality in the subset of patients with no post-procedural aortic regurgitation (HR: 1.88; p = 0.02). CONCLUSIONS In patients with severe aortic stenosis and high surgical risk, PPM is more frequent and more often severe following SAVR than TAVR. Patients with PPM after SAVR have worse survival and less LV mass regression than those without PPM. Severe PPM also has a significant impact on survival after TAVR in the subset of patients with no post-procedural aortic regurgitation. TAVR may be preferable to SAVR in patients with a small aortic annulus who are susceptible to PPM to avoid its adverse impact on LV mass regression and survival.