Patient–prosthesis mismatch in mitral annuloplasty for degenerative mitral regurgitation: an ignored issue

Abstract

Abstract OBJECTIVES Elevated postoperative transmitral gradient (TMG), partially induced by a small annuloplasty ring, is associated with late atrial fibrillation (AF) after mitral valve repair. Here, we aimed to provide the optimal cut-off of prosthetic ring size to reduce patient–prosthesis mismatch (PPM) after mitral annuloplasty. METHODS From 2006 to 2017, 262 patients who underwent mitral valve repair for degenerative pathologies were retrospectively studied. The relationships of body surface area (BSA)–indexed prosthetic orifice area (POAi)–postoperative TMG and POAi–late AF were tested using regression curves and receiver operating characteristic curves, respectively. The optimal cut-off of POAi predictive of late AF was used to define PPM. Baseline and follow-up data of patients with and without PPM were compared in propensity score-matched cohorts. RESULTS In-hospital mortality was 0. Late AF was observed in 9.2% (24/262) patients during a median follow-up of 3.8 years. An exponential model was best fitted based on the POAi–postoperative TMG relationship (P < 0.001). Using late AF as the dependent variable, the optimal cut-off for PPM was POAi ≤2.28 cm2/m2 (c-statistic 0.71; sensitivity 0.61; specificity 0.80; P < 0.001). PPM was identified in 113 (43.1%) patients. After propensity score matching, the estimated 5-year rate of late AF was significantly higher in PPM patients than in non-PPM patients (24% vs 5%; P < 0.001). CONCLUSIONS Postoperative TMG increases significantly with a small POAi for full ring annuloplasty. A patient’s BSA should be considered in addition to valvular dimensions during the selection of a proper ring size to reduce PPM-related AF.