Prosthesis-patient Mismatch after Mitral Valve Replacement Stratified by Referred and Measured Effective Valve Area

Objective: The aim of this study was to determine the impact of patient-prosthesis mismatch (PPM) after mitral valve replacement (MVR) on the late clinical outcome, evaluated from the referred value and measured mitral valve area in the echocardiograph. Patients and Method: The records of 212 patients who underwent MVR between 1995 and 2008 at Funabashi Municipal Medical Center, Japan were studied retrospectively. Exclusions were patients who had a repeat MVR or concomitant aortic valve surgery. Of 212 patients, 163 underwent the Doppler echocardiographic study more than 1 year after surgery. Primary endpoint was late survival, and secondary endpoint was major adverse cardiac event (MACE). The average follow-up period was 53.1 ± 100.8 months. The effective orifice area index (EOAI) was calculated using the referred effective orifice area (r-EOA) and measured effective orifice area (m-EOA). An EOAI smaller than 1.2 cm2/m2 defined PPM. Results: For r-EOAI, 125 patients (group P) had PPM and 87patients (group N) did not. Between groups, there was a significant difference in the proportion of males (group P vs. N; 59% vs. 23%; P = 0.0001), postoperative NYHA class (1.02 ± 6.2 vs. 9.8 ± 1.6, P = 0.04), late mitral valve area (MVA) (2.50 ± 0.56 vs. 2.78 ± 0.60, P = 0.005), and peak transmitral pressure gradient (MPG) 11.9 ± 6.2 vs 9.8 ± 1.6, P = 0.04). However, there was no difference in late survival (P = 0.55) or incidence of a major cardiac adverse event (MACE) (P = 0.14). For m-EOAI, 17 patients (group P) had PPM and 146 patients (group N) did not. Between groups, there was a difference in the bioprosthetic valve (group P vs. N; 76% vs. 26%, P = 0.006) and mean MPG (5.2 ± 2.3 vs. 3.7 ± 1.8, P = 0.02). However, there was no difference in late survival (P = 0.99) and incidence of MACE (P = 0.86). The r- and m-EOAI were well correlated (correlation coefficient 0.46; 0.33-0.5) Conclusions: The PPM after MVR was not related to the late survival or the incidence of MACE based on both r- and m-EOAI. The patient group of PPM defined by r-EOAI tended to be male and that defined by m-EOAI tended to be bioprosthetic.