Prognostic significance of right ventricular-pulmonary artery coupling in patients undergoing tricuspid valve surgery

The accurate evaluation of right ventricular function and its response to correction of tricuspid valve pathology are challenging. This retrospective study evaluated the predictive value of right ventricular-pulmonary arterial (RV-PA) coupling in patients undergoing isolated or combined tricuspid and mitral valve surgery.

Patients at Massachusetts General Hospital who underwent isolated tricuspid or combined tricuspid and mitral valve surgery between January 2013 and June 2024 with available preoperative transthoracic echocardiography images were included. The RV-PA coupling ratio was calculated by dividing the tricuspid annular plane systolic excursion (TAPSE) by PA systolic pressure. The optimal cut-off value for this ratio was determined using the maximal log-rank test. The primary outcome was mid-term survival, while secondary outcomes included in-hospital mortality, intensive care unit (ICU) stay duration, hospital stay, and prolonged postoperative inotrope use.

A total of 264 patients were followed for a median of 23 months (interquartile range, 7.0-48.0 months). The optimal RV-PA coupling ratio linked to mortality was 0.339 mm/mmHg. Patients with an RV-PA coupling ratio of ≤0.339 mm/mmHg had significantly higher all-cause mortality (25.5% vs. 10.0%; P<0.002), longer median ICU stay (4.0 vs. 3.0 days; P<0.001), longer median hospital stay (11.5 vs. 9.0 days; P=0.002), increased need for inotropic support (45.7% vs. 21.8%; P<0.001), and higher in-hospital mortality (10.6% vs. 2.9%). In multivariable Cox regression analysis, an RV-PA coupling ratio >0.339 mm/mmHg was linked to a reduced risk of all-cause mortality (hazard ratio 0.09, P=0.003). TAPSE and RV free-wall strain showed no association with mortality.

Echocardiography-derived RV-PA coupling is a robust, independent predictor of adverse outcomes in patients undergoing tricuspid valve surgery, particularly in those undergoing combined procedures. It captures a critical dimension of RV physiology not fully appreciated by standard measures and may serve as a powerful tool in surgical risk stratification and patient selection.