Immediate impact of successful percutaneous balloon mitral valvuloplasty on right and left ventricular functions: An echocardiographic study using load independent tissue velocity imaging indices.

BACKGROUND: The impact of successful percutaneous balloon mitral valvuloplasty (PBMV) on left ventricular (LV) function has been a controversial subject. This study aimed to determine the immediate impact of PBMV on biventricular function using recent Tissue Velocity Imaging (TVI) derived load-independent indices.

METHODS AND RESULTS: A total of 30 patients with severe mitral stenosis (MS) who underwent PBMV at a tertiary center of India from August 2012 to December 2013 were included in the study. Thirty age-matched and gender-matched healthy controls were also enrolled. Out of 30 patients, 27(90%) were female. Mean mitral valve area (MVA) of patients before and after PBMV was 0.78 and 1.82cm2 (p<0.001), respectively. All TVI-derived LV and RV basal systolic (IVCV, Sm and the relatively load independent IVA) and diastolic velocities (Em, Em/Am) were significantly decreased in patients with MS compared to controls (p<0.001 for all) which improved significantly after PBMV (6.4±0.7 vs 11±1.6; 5.8±0.7 vs 9.9±1.6; 1.5±0.3 vs 4.2±0.6; 6.4±0.6 vs 13.1±2.1; 0.7±0.1 vs 1.7±0.2 for mitral annulus respectively, p<0.001 for all). Increment in MVA positively correlated with Tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular Sm and isovolumic contraction velocity (IVCV) and inversely with left atrium (LA) size and Pulmonary arterial systolic pressure (PASP) (p=0.01 for LA size; p<0.001 for others) while no such correlation was found with mitral annulus isovolumic acceleration (IVA) (r=-0.078; p=0.679).

CONCLUSION: The improved right ventricular (RV) function appears to be predominantly due to afterload reduction, while that of LV appears to be more due to the acute relief of mechanical restraint.