Right Ventricular-Pulmonary Arterial Coupling in Secondary Tricuspid Regurgitation

Chronic pressure-overload induces right ventricular (RV) adaptation to maintain RV-pulmonary arterial (PA) coupling. RV remodeling is frequently associated with secondary tricuspid regurgitation (TR) which may accelerate uncoupling. Our aim is to determine whether the non-invasive analysis of RV-PA coupling could improve risk stratification in patients with secondary TR. A total of 1,149 patients (median age 72[IQR, 63 to 79] years, 51% men) with moderate or severe secondary TR were included. RV-PA coupling was estimated using the ratio between two standard echocardiographic measurements: tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP). The risk of all-cause mortality across different values of TAPSE/PASP was analyzed with a spline analysis. The cut-off value of TAPSE/PASP to identify RV-PA uncoupling was based on the spline curve analysis. At the time of significant secondary TR diagnosis the median TAPSE/PASP was 0.35 (IQR, 0.25 to 0.49) mm/mm Hg. A total of 470 patients (41%) demonstrated RV-PA uncoupling (<0.31 mm/mm Hg). Patients with RV-PA uncoupling presented more frequently with heart failure symptoms had larger RV and left ventricular dimensions, and more severe TR compared to those with RV-PA coupling. During a median follow-up of 51 (IQR, 17 to 86) months, 586 patients (51%) died. The cumulative 5-year survival rate was lower in patients with RV-PA uncoupling compared to their counterparts (37% vs 64%, p < 0.001). After correcting for potential confounders, RV-PA uncoupling was the only echocardiographic parameter independently associated with all-cause mortality (HR 1.462; 95% CI 1.192 to 1.793; p < 0.001). In conclusion, RV-PA uncoupling in patients with secondary TR is independently associated with poor prognosis and may improve risk stratification.