Mitral Patient-Prosthesis Mismatch Predicts Suboptimal Hemodynamic Recovery after Mitral Valve Replacement

A possible relationship between an obstructive prosthesis and suboptimal hemodynamic recovery, as reflected by unsatisfactory regression in systolic pulmonary artery pressure (sPAP) and functional tricuspid regurgitation (FTR) following mitral valve replacement (MVR), was investigated. A delineating effective orifice area index (EOAI) value was sought in order to define a patient-prosthesis mismatch.

A total of 128 patients undergoing isolated mechanical MVR were followed up for a mean of 46 ± 9 months. Patients were allocated to two groups. Group I comprised 83 patients (65%) exhibiting a satisfactory (≥30%) regression in sPAP and FTR, while group II comprised 45 patients with a <30% (suboptimal) decrease in these parameters. A cutoff value for the prosthetic mitral valve in-vivo EAOI was explored as a predictor of postoperative hemodynamic recovery.

The mean in-vivo EOAI differed significantly between the groups (1.23 cm2/m2 in group I versus 1.11 cm2/m2 in group II; p <0.0001). The consequent receiver operating characteristic curve analysis revealed an EOAI of 1.19 cm2/m2 as the cut-off value, below which a suboptimal postoperative regression in pulmonary hypertension and FTR is predicted.

An in-vivo EOAI <1.19 cm2/m2 strongly suggests a suboptimal hemodynamic recovery following MVR with the bileaflet mechanical prosthesis used in the present study. Although no direct relationship between prosthesis size and in vivo EOAI was demonstrated, the logical approach is to implant a prosthesis of the largest possible size.