Prognostic value of right ventricular-pulmonary arterial coupling indices in patients with moderate to severe mitral stenosis

Abstract Background Right ventricular-pulmonary arterial (RV-PA) coupling represents the relationship of RV contractility and RV afterload. The ability of RV to adapt to changes in RV afterload (i.e. increased pulmonary arterial (PA) loading) has prognostic implications in various cardiovascular diseases such as heart failure and pulmonary arterial hypertension. RV-PA uncoupling occurs when RV contractility cannot match RV afterload, resulting in right heart dysfunction. However, RV-PA coupling has not been investigated in mitral stenosis patients. Purpose To evaluate the prognostic significance of various non-invasive RV-PA coupling parameters (TAPSE/PASP and RVFWLS/PASP) in patients with moderate to severe mitral stenosis. Methods This was a single-center retrospective study of 237 patients with moderate or severe mitral stenosis enrolled between January 2010 to December 2022. Baseline clinical and echocardiographic parameters were collected. RV free wall longitudinal strain (RVFWLS) was subsequently analyzed using TOMTEC software. Echocardiography-derived RV-PA coupling parameters were collected, including TAPSE/PASP and RVFWLS/PASP. The primary endpoint was a composite outcome of all-cause mortality, heart failure hospitalization and valve intervention (percutaneous transvenous mitral commissurotomy and surgical intervention). RV parameters were analyzed separately to avoid collinearity. Results A total of 237 patients were included in the study. The patients had a mean age was 66.56 ± 13.61 years-old and were predominantly female (67.9%). The median follow-up duration was 4.54 years (IQR 1.44 – 6.44). Mean left ventricular ejection fraction (LVEF) was 56.86 ± 10.51%, mean TAPSE 18.29 ± 5.36 mm and mean RVFWLS was -23.60 ± 7.96 %. In separate multivariable Cox regression models after adjustment for age , sex and mitral stenosis severity, TAPSE/PASP ratio < 0.36mm/mmHg (HR 2.025 , 95% CI 1.395-2.939, p < 0.001 ) and RVFWLS/PASP ratio ≥ - 0.5%/mm Hg (HR 2.031 95% CI 1.404 – 2.938 , p< 0.001) remained independently associated with mortality , heart failure hospitalization and valve intervention. Conclusion TAPSE/PASP and RVFWLS/PASP were independently associated with all-cause mortality, heart failure hospitalization and valve intervention in patients with moderate to severe mitral stenosis.