710 The Effect of Mitral Valve Surgery on Left Ventricular Remodelling and Function in Paediatric Patients With Rheumatic Heart Disease: An Echocardiographic Study

Abstract

Rheumatic heart disease (RHD) commonly results in mitral regurgitation (MR). The effects of left ventricular (LV) volume loading and alleviation on LV remodelling remains incompletely studied in children. MR in RHD allows investigation of haemodynamic measures without confounding congenital heart disease. We assessed the effects of MR and repair on LV myocardial mechanics, remodelling and function in children with RHD. Paediatric patients who underwent mitral valve repair or replacement for isolated RHD-MR from 2004 to 2019 with adequate echocardiographic studies were retrospectively assessed pre- and postoperatively and compared to matched controls. Eighteen patients underwent mitral valve surgery during the study period. Postoperatively there was a significant reduction in left atrial (LA) (p=0.001) and LV end-diastolic M-mode dimensions (p=0.001) and volumes (p=0.006), with no change in LV end-systolic volumes, yielding a significant reduction in LV functional measures (fractional shortening (34.5 vs 31.5%, p=0.006), four-chamber ejection fraction (62.6 vs 51.7%, p=0.002) and LV longitudinal strain (-24.3 vs -18.2%, p<0.001). Compared to controls, LA and LV dimensions remained increased with a reduction in all functional parameters after repair. There was a moderate negative correlation between preoperative end-diastolic volumes and postoperative longitudinal strain (r2=0.35). Persistent LV and LA remodelling with decreased LV function is observed after repair of RHD-MR. While these results reflect changes to volume loading, the unmasking of decreased LV function and persistent remodelling; and linear relation to preoperative LV size, may suggest that early intervention to alleviate MR could benefit selected patients and warrants further study.