Impact of transcatheter edge-to-edge mitral valve repair on right ventricular function

Abstract

Development of transcatheter techniques procedures have modified mitral regurgitation management. The technique of edge-to-edge mitral valve repair (TEEMVR) with MitraClip© induces a certain degree of mitral stenosis, that could impact right ventricular function. The aim of this study is to evaluate impact of TEEMVR on right ventricular morphology and function and pulmonary artery pressures up to 1 year after procedure. In this observational retrospective study, we collected echocardiographic parameters before, at 6 months and 1 year after procedure. We analyzed right ventricular dimensions and systolic function, pulmonary artery pressures, and tricuspid regurgitation. A comparison between patients with a transmitral gradient below or above 5 mmHg at day one after procedure was performed. Forty three patients aged 77,5 ± 11,8 years underwent TEEMVR between 2015 and 2020, 60% had primary mitral regurgitation. A significant reduction of tricuspid regurgitation severity was observed: grade 2,0 ± 0,8 before, 1,6 ± 0,7 at 6 months and 1,7 ± 0,8 at 1 year ( P = 0,03 and P = 0,02 respectively). No significant difference in right ventricular systolic function was observed during follow-up. In the population of secondary mitral regurgitation, a significant increase of right ventricular fractional area shortening between 6 months and 1 year was noted (25 ± 10% at 6 months and 31 ± 5% at 1 year; P = 0,04). A decrease in pulmonary artery pressures at 6 months was observed in the general population (50 ± 1 mmHg before clip vs 43 ± 14 mmHg at 6 months; P = 0,03). In patients presenting with a transmitral gradient below 5 mmHg at day one, a decrease in pulmonary pressures was observed at 6 months whereas those with a gradient above 5 mmHg did not. Left ventricular ejection fraction decreased (from 48 ± 17,2% before, 44,5 ± 15,4% at 6 months and 43,3 ± 16,1% at 1 year; P = 0,01, P = 0,02 respectively). End-diastolic left ventricular diameter and volume decreased at 6 months (59 ± 9 mm and 56 ± 13 mm at 6 months; P = 0,025 and 147 ± 58 mL vs 141 ± 75 mL at 6 months; P = 0,01). Few changes in right ventricular morphology and function after TEEMVR were observed in our study. However, patients with transmitral gradient below 5 mmHg demonstrated greater decrease in pulmonary artery pressures. Further studies with a longer follow-up could help in understanding impact of TEEMVR on right ventricular physiology.