Effects of Percutaneous Balloon Mitral Valvuloplasty on Left Ventricular Deformation in Patients with Isolated Severe Mitral Stenosis: A Speckle-Tracking Strain Echocardiographic Study

Abstract

Previous studies have reported abnormal left ventricular (LV) contraction in patients with mitral stenosis (MS). The aim of this study was to explore the serial changes in LV mechanics in patients with severe MS undergoing balloon mitral valvuloplasty (BMV) to understand the reversibility and determinants of abnormal LV contractile function. Fifty-seven patients with severe MS and 19 healthy controls underwent echocardiographic examinations, including two-dimensional speckle-tracking-based LV global longitudinal strain (GLS) and global circumferential strain measurements. In patients with MS, the same measurements were repeated 72 hours after BMV. In comparison with controls, patients with MS had faster heart rates and lower LV end-diastolic volumes and LV ejection fractions (P= .008). The magnitudes of both GLS and global circumferential strain were reduced in patients with MS (P < .001 for both), with 48 patients (84.2%) having GLS below the 25th percentile of controls. BMV resulted in significant improvements in GLS and global circumferential strain (-14.6 ± 3.3% vs -17.8 ± 3.5% and -20.0 ± 5.0% vs -22.5 ± 4.6%, respectively, P < .005 for both). On multivariate analysis, left atrial volume, mean transmitral gradient, and LV end-diastolic volume were independently correlated with baseline GLS, whereas increment in LV end-diastolic volume was the only determinant of increased GLS after BMV. LV deformation is reduced in patients with severe MS and is related to the hemodynamic severity of MS. BMV results in rapid improvement of LV deformation, which is correlated with serial improvement in LV diastolic loading. These findings suggest that reduced LV diastolic filling rather than an irreversible myocardial structural abnormality contributes predominantly to reduced LV mechanical performance in patients with MS.