Right ventricular to pulmonary arterial coupling as a predictor of survival in patients undergoing mitral valve surgery for mitral regurgitation

Objectives: Right ventricular-to-pulmonary artery coupling has been associated with outcomes in mitral regurgitation treated by transcatheter approaches. We evaluated right ventricular-to-pulmonary artery coupling as a predictor of survival and postoperative length of hospital stay (LOS) in patients with mitral regurgitation undergoing mitral valve surgery.

Methods: In this retrospective analysis (median follow-up: 5.8 years), right ventricular-to-pulmonary artery coupling was quantified as the ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) using transthoracic echocardiography. Receiver operating characteristic curve analysis was used to determine the optimum cut-point of TAPSE/PASP to predict all-cause mortality, and the study population was dichotomized according to this value. The primary end point was all-cause mortality. A secondary end point of LOS was also assessed.

Results: Out of 142 patients (median age: 67, female: 49%), 35 showed impaired coupling at baseline (TAPSE/PASP ≤0.35). Patients with TAPSE/PASP ≤0.35 had higher absolute mortality (37% vs 8%, P < 0.001) and longer LOS (7 days vs 9 days, P = 0.04). Kaplan-Meier analysis revealed lower survival in patients with TAPSE/PASP ≤0.35 (log-rank: P < 0.0001). In multivariable Cox regression, TAPSE/PASP ≤0.35 was the most significant predictor of all-cause mortality (hazard ratio: 3.69, 95% confidence interval 1.31-10.1, P = 0.011), alongside chronic obstructive pulmonary disease and estimated glomerular filtration rate. TAPSE/PASP ≤0.35 was associated with significantly increased LOS (β: 4.6, 95% confidence interval 0.66-8.5, P = 0.022) alongside left ventricular ejection fraction, mitral valve replacement and urgent operation.

Conclusions: In mitral regurgitation patients undergoing mitral valve surgery, TAPSE/PASP ≤0.35 is associated with increased mortality and LOS. Further validation is indicated in larger, prospective cohorts.