Clinical Impact of Flow Adjusted Transmitral Pressure Gradient After Surgical Annuloplasty for Functional Mitral Regurgitation

Abstract

Downsizing of mitral annulus due to mitral annuloplasty for ischemic functional mitral regurgitation (FMR) raises a new issue, functional mitral stenosis (FMS), defined as a decline of mitral hemodynamics. However, common mitral hemodynamic parameters are influenced by transmitral flow, therefore, the clinical impacts are still controversial. The aim of this study is to seek mitral hemodynamic indices (including transmitlra pressure gradient [TMPG] adjusted by left ventricular stroke volume [LVSV]) relevant to the mid-term outcomes after annuloplasty for ischemic functional mitral regurgitation (FMR). This study is a retrospective evaluation of mitral valve hemodynamic status by resting echocardiogram at several weeks after surgery. Eighty-one patients underwent mitral annuloplasty for ischemic FMR between September 2012 and June 2019. Postoperative adverse events occurred in 28 patients (34.6%), and the overall 5-year freedom from adverse events rate was 55.9%. Common mitral hemodynamic parameters were not associated with adverse events, but flow adjusted TMPG can be a correlative factor. By multivariable analysis, postoperative systolic pulmonary artery pressure and peak TMPG/LVSV were detected as independent predictors (adjusted hazard ratio 1.07 and 1.08, P < 0.001 and < 0.001). Additionally, risk stratification by peak TMPG (cut-off: 10 mm Hg) and LVSV (cut-off: 35 mL/m2) reflected the mid-term outcomes, perceptively (P = 0.007). Conventional mitral hemodynamic parameters were not associated with adverse cardiac events after annuloplasty for ischemic FMR. However, flow adjusted TMPG was identfied as an independent predictor, and risk stratification by peak TMPG and LVSV reflected the mid-term outcomes, perceptively.