Left atrial structural and functional remodeling following balloon mitral valvuloplasty

Mitral stenosis (MS) is associated with left atrial (LA) functional and morphological changes as a result of chronic increase in LA pressure. Relieving the mitral obstruction via balloon mitral valvuloplasty (BMV) might be associated with LA structural and functional remodeling. To study alterations of LA volume and functions 1 year following successful BMV in patients with isolated rheumatic severe mitral stenosis. Thirty patients (median age 33 years, 22 women) with severe rheumatic MS were included in the study. Using biplane method, trans-thoracic 2D echocardiography was used to estimate LA volume indexed to body surface area (BSA). Maximal, minimal and pre-A left atrial volumes were measured and indexed to BSA. LA volumetric functions were then assessed and the measurements were repeated 6 months and 1 year after successful valvuloplasty. At baseline, median mitral valve area (MVA) was 0.9 (0.6-1.3) cm² measured by planimetry with a mean pressure gradient of 12.5 (8-24) mmHg. Following BMV, a significant regression of left atrial volume index was noticed at 6 months compared to baseline (51 vs. 60 ml/m², p = 0.001) with a further decrease at 1 year (48 vs. 51 ml/m², p = 0.03). At 6 months, volumetric assessment of left atrial functions showed a significant improvement in LA total emptying fraction (42% vs 30%, p = 0.001) as well as in LA passive emptying fraction (26% vs 14%, p = 0.033) and LA active emptying fraction (20% vs. 18%, p = 0.016). All these indices showed further improvement at 1 year [47% (P = 0.02), 29% (p = 0.03) and 31% (p = 0.001) respectively]. In patients with isolated rheumatic MS, mitral valvuloplasty was associated with a significant decline of LA volume accompanied by a significant improvement of its volumetric functions.