Prognostic Implications of Right Ventricular-Pulmonary Arterial Coupling Derived from Right Ventricular Strain in Secondary Tricuspid Regurgitation

BACKGROUND: Right ventricular (RV)-pulmonary arterial (PA) coupling is a key determinant of prognosis in moderate and severe secondary tricuspid regurgitation (TR), reflecting the complex interplay between RV contractility and afterload. RV free wall longitudinal strain (RVFWLS) provides a less angle- and load-dependent estimate of RV contractility than tricuspid annular plane systolic excursion (TAPSE). This study evaluated the prognostic utility of the RVFWLS/pulmonary artery systolic pressure (PASP) ratio in secondary TR, its association with excess mortality relative to a matched general population, and whether it provides incremental value beyond the established TAPSE/PASP ratio. METHODS: A total of 1,007 patients (71 [IQR 62-78] years, 51% male) were followed up for the endpoint of all-cause mortality from the diagnosis of moderate or severe TR. RESULTS: Over a median follow-up of 59 (IQR 19 to 100) months, 564 (56%) patients died. In a comprehensive multivariable model, the RVFWLS/PASP ratio remained independently associated with all-cause mortality (adjusted HR 1.13 per 0.10 decrease below 0.60, 95% CI 1.07 to 1.19, P<0.0001) and was associated with substantial excess mortality when compared to the matched general population, with spline curve analysis showing increased mortality beginning at values <0.60. The LR χ CONCLUSION: The RVFWLS/PASP ratio is independently associated with mortality in patients with moderate and severe secondary TR, identifies patients with substantial excess mortality relative to the general population, and adds incremental prognostic value over the TAPSE/PASP ratio, highlighting its potential as a more precise non-invasive marker of RV-PA coupling.