Prognostic impact of right ventricular to pulmonary arterial coupling for patients undergoing surgery for severe mitral regurgitation

Cardiac surgery may induce abrupt changes in pre-load, afterload, and right ventricular contractility. The ability of the right ventricle to maintain systolic performance in the presence of increased afterload is referred to as right ventricular-pulmonary artery (RV-PA) coupling. To assess RV-PA coupling in patients undergoing surgery for severe mitral regurgitation (MR), to identify a tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) threshold for RV-PA uncoupling, and to evaluate its prognostic value for early mortality, right heart failure (RHF), post-operative course, and late mortality.

This retrospective single-centre observational study included 277 patients who underwent surgery for severe MR between January 2018 and March 2023. RV-PA coupling was assessed using the ratio of TAPSE/PASP derived from pre-operative transthoracic echocardiography. The primary endpoint was early all-cause mortality within 30 days. Secondary endpoints included mortality from RHF, length of intensive care unit (ICU) stay, length of hospital stay, and late all-cause mortality.Receiver operating characteristic analysis identified an optimal TAPSE/PASP cut-off of 0.30 mm/mmHg to define RV-PA uncoupling. Patients with TAPSE/PASP ≤0.30 mm/mmHg had significantly higher early mortality and worse post-operative outcomes. In multivariable logistic regression, TAPSE/PASP remained an independent predictor of early mortality together with EuroSCORE II, cardiopulmonary bypass time, and weaning from bypass requiring ECMO or inotropic support. In a sensitivity analysis restricted to isolated mitral valve (MV) surgery, TAPSE/PASP remained the only independent predictor of early mortality. RV-PA uncoupling was also associated with excess early mortality from RHF and longer ICU and hospital stay, but not with late mortality.

Pre-operative RV-PA uncoupling assessed by TAPSE/PASP is strongly associated with early mortality and post-operative RHF after MV surgery for severe MR and may help refine perioperative risk stratification.