Decrease in left atrium volume after successful balloon mitral valvuloplasty: an echocardiographic and hemodynamic study.

Background: Left atrium (LA) remodeling has a crucial adverse impact on outcome and prognosis in mitral stenosis. Few studies have reported the effect of balloon mitral valvuloplasty (BMV) on LA volume. The aim of this study was to assess the evolution of LA volume immediately and 1 month after successful BMV in patients in sinus rhythm.

Methods: Thirty-three consecutive patients (70% women; age 31 ± 8 years; range 19-45) with moderate to severe mitral stenosis (mitral valve area ≤1.5 cm(2) ) who underwent successful BMV were included prospectively. Using two-dimensional echocardiography, and according to the prolate ellipse method, LA volume and LA volume indexed to body surface area were determined before BMV, and 24 hours and 1 month after BMV. Tricuspid and pulmonary regurgitation jets were recorded systematically using continuous-wave Doppler. Pulmonary artery-right ventricular (PA-RV) gradients, reflecting pulmonary pressures, and pulmonary vascular resistance were measured.

Results: Mitral valve area increased from 0.88 ± 0.16 to 1.55 ± 0.26 cm(2) (P < 0.0001). Mean mitral valve gradient (MVG) decreased from 16 ± 6 to 6 ± 2 mmHg (P < 0.0001) immediately after BMV. Indexed LA volume fell from 56 ± 14 to 48 ± 12 mL/m(2) (P = 0.0002) immediately after BMV and to 45 ± 13 mL/m(2) at 1 month (P < 0.0001). Only patients with a median LA volume ≥55 mL/m(2) before BMV had a significant reduction in LA volume (P = 0.0001). Decrease in LA volume was correlated with decreases in PA-RV peak diastolic gradient (r = 0.45, P = 0.008) and MVG (r = 0.35, P = 0.04).

Conclusion: In patients with mitral stenosis in sinus rhythm, successful BMV results in an immediate decrease in LA volume. This reduction, maximal immediately after BMV, correlates with decreases in MVG and PA-RV peak diastolic gradient, and is significant only when LA volume before BMV is severely enlarged.