[The frequency of prosthesis-patient mismatch after mechanical mitral valve replacement and its effect on postoperative systolic pulmonary arterial pressure].

We investigated the frequency of prosthesis-patient mismatch (PPM) after mechanical mitral valve replacement (MVR), its effect on postoperative systolic pulmonary arterial pressure (PAP), and the relationship of indexed effective orifice area (EOA) with systolic PAP and hemodynamic variables of the prosthetic valve.The study included 100 patients (27 men, 73 women; mean age 51+/-11 years) with a normally functioning mechanical mitral valve prosthesis. Prosthetic mitral EOA, indexed EOA, and net atrioventricular compliance (Cn) were estimated by Doppler echocardiography. Prosthesis-patient mismatch was defined as an indexed EOA or=40 mmHg.The frequencies of PPM and postoperative persistent PHT were 33% and 31%, respectively. Postoperative persistent PHT was seen in 79% and 8% in patients with and without PPM, respectively (p<0.001). The frequency of low Cn was significantly higher in patients with PPM (60% vs. 31%; p<0.001). Postoperative systolic PAP was significantly higher in patients with PPM (42.0+/-6.6 mmHg vs. 29.9+/-6.0 mmHg, p<0.0001) and in 41 patients having a low Cn compared to 59 patients having a high Cn (37.2+/-8.8 mmHg vs. 31.6+/-7.4 mmHg, p<0.001). Postoperative systolic PAP was significantly correlated with indexed EOA (r=-0.535, p<0.001) and Cn (r=-0.422, p<0.001), whereas prosthetic valve size was not correlated with systolic PAP (r=0.022, p=0.829) and indexed EOA (r=0.008, p=0.93). In multivariate regression analysis, indexed EOA, age, mean transprosthetic gradient, and Cn were independent factors affecting systolic PAP.Prosthesis-patient mismatch after MVR is associated with persistent PHT. Use of a prosthetic valve that is compatible to the body surface area may significantly reduce the incidence of PPM, and thus the frequency of persistent PHT.