Prosthesis patient mismatch with latest generation supra-annular prostheses. The beginning of the end?

Abstract

Most studies about prosthesis–patient mismatch (PPM) were conducted before the introduction of new high-performance prostheses. Nowadays, PPM could become unfrequent. Our aim was to study the impact of new prostheses on PPM in comparison with previous experience. Prosthetic Indexed Effective Orifice Area (EOAi) was estimated in two historical cohorts. Group A: 339 patients undergoing AVR from Mar 94–Nov 01. Group B: 404 operated on during the last three years when latest generation prostheses were implanted. Incidence, determinants of PPM and clinical results were studied. Moderate PPM (EOAi ≤0.85 cm²/m²) was present in 38% and 19% (respective groups). Mean EOAi increased from 1.02±0.29 cm²/m² to 1.11±0.27 cm²/m². ‘Group B’ and ‘new prostheses’ were protective. Thirty-day mortality was 3.8% and 4.7% with higher rate in patients with increased left ventricular mass index (LVMI), especially if PPM was present: 14.7 vs. 2.1% (P<0.05) in Group A; 25.0 vs. 4.8% (P<0.05) in Group B (PPM vs. no-PPM). LVMI regression was impaired in these patients. Moderate PPM was an independent predictor of late cardiac mortality (OR: 3.38, 95% CI: 1.37–8.31; P<0.01). PPM is a prognostic factor for late cardiac death. Its impact on early mortality is only relevant in patients with high LVMI. Its incidence has decreased with the use of new prostheses.