Prosthesis-patient mismatch is associated with long-term mortality following surgical aortic valve replacement
Authors: Mazine A , Chu A , Rocha R , Yau T M , Rao V , Pibarot P , Lee D S , David T E , Ouzounian M 
Published: October 2024

Abstract

Background
Prosthesis-patient mismatch (PPM) refers to a situation where the indexed effective orifice area (iEOA) of an implanted prosthetic valve is too small relative to the patient's body size, resulting in hemodynamic compromise. Studies examining the long-term consequences of PPM after surgical aortic valve replacement (SAVR) have yielded conflicting results.

Purpose
To evaluate the impact of PPM on long-term outcomes in patients undergoing primary isolated SAVR.

Methods
All patients who underwent isolated first-time SAVR from 1990-2014 were included in this observational, single-center study. PPM was deﬁned as a predicted iEOA &lt;0.85 cm2/m2 and severe PPM was deﬁned as an iEOA &lt;0.65 cm2/m2. Patient demographics, surgical details, and in-hospital outcomes were prospectively collected in our institutional database. Cases were linked to provincial administrative databases at an independent, non-profit research institute whose legal status allows it to collect and analyze health care and demographic data. The primary outcome of interest was all-cause mortality. Secondary outcomes were aortic valve reoperation (surgical or transcatheter) and post-operative hospitalization for heart failure. Multivariable Cox regression analysis identified risk factors for long-term mortality. Kaplan-Meier curves were generated for long-term survival and cumulative incidence functions for aortic valve reoperation and heart failure hospitalization.

Results
A total of 1,798 patients were included (no PPM: 770 [43%]; moderate PPM: 943 [52%]; and severe PPM: 85 [5%]). Mean age was 64±13 years, and 750 (42%) were female. 451 (25%) patients received a mechanical valve, and 1347 (75%) received a stented bioprosthetic valve. Concomitant aortic root enlargement was performed in 492 (27%) patients. At 20 years, survival was 47.8% (95% CI: 43.2%–52.2%) in the "no PPM group" compared with 29.5% (95% CI: 25.6%–33.5%) and 24.7% (95% CI: 12.7%–38.8%) in the moderate and severe PPM groups, respectively (p&lt;0.001) (Figure 1). On multivariable analysis, iEOA was independently associated with long-term mortality (HR 0.95 per 0.10 increase in iEOA, 95% CI [0.91–0.98]; p=0.007). In a pre-specified subgroup analysis, iEOA was found to be associated with late mortality in patients younger than 65 years (p&lt;0.001) but not in patients 65 years and older (p=0.23). Readmission for heart failure was more frequent among patients who had PPM than those who did not (Figure 2). There was no difference in aortic valve reintervention in patients with or without PPM (p=0.654).

Conclusions
Prosthesis-patient mismatch is common after SAVR and is associated with late mortality and hospitalization for heart failure. The deleterious impact of PPM on survival appears more pronounced in young patients. These findings may have important implications for the lifetime management of patients with aortic valve disease.Survival post SAVRHeart failure hospitalization post SAVR