Prosthesis-Patient Mismatch After Aortic Valve Replacement in the PARTNER 2 Trial and Registry

Objectives: This study aimed to compare incidence and impact of measured prosthesis-patient mismatch (PPM_M) versus predicted PPM (PPM_P) after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR).

Background: TAVR studies have used measured effective orifice area indexed (EOAi) to body surface area (BSA) to define PPM, but most SAVR series have used predicted EOAi. This difference may contribute to discrepancies in incidence and outcomes of PPM between series.

Methods: The study analyzed SAVR patients from the PARTNER (Placement of Aortic Transcatheter Valves) 2A trial and TAVR patients from the PARTNER 2 SAPIEN 3 Intermediate Risk registry. PPM was classified as moderate if EOAi ≤0.85 cm²/m² (≤0.70 if obese: body mass index ≥30 kg/m²) and severe if EOAi ≤0.65 cm²/m² (≤0.55 if obese). PPM_M was determined by the core lab-measured EOAi on 30-day echocardiogram. PPM_P was determined by 2 methods: 1) using normal EOA reference values previously reported for each valve model and size (PPM_P1; n = 929 SAVR, 1,069 TAVR) indexed to BSA; and 2) using normal reference EOA predicted from aortic annulus size measured by computed tomography (PPM_P2; n = 864 TAVR only) indexed to BSA. Primary endpoint was the composite of 5-year all-cause death and rehospitalization.

Results: The incidence of moderate and severe PPM_P was much lower than PPM_M in both SAVR (PPM_P1: 28.4% and 1.2% vs. PPM_M: 31.0% and 23.6%) and TAVR (PPM_P1: 21.0% and 0.1% and PPM_P2: 17.0% and 0% vs. PPM_M: 27.9% and 5.7%). The incidence of severe PPM_M and severe PPM_P1 was lower in TAVR versus SAVR (P < 0.001). The presence of PPM by any method was associated with higher transprosthetic gradient. Severe PPM_P1 was independently associated with events in SAVR after adjustment for sex and Society of Thoracic Surgeons score (hazard ratio: 3.18;95% CI: 1.69-5.96; P < 0.001), whereas no association was observed between PPM by any method and outcomes in TAVR.

Conclusions: EOAi measured by echocardiography results in a higher incidence of PPM following SAVR or TAVR than PPM based on predicted EOAi. Severe PPM_P is rare (<1.5%), but is associated with increased all-cause death and rehospitalization after SAVR, whereas it is absent following TAVR.