Immediate impact of successful percutaneous mitral valve commissurotomy on right ventricular function

Abstract

Mitral stenosis (MS) affects right ventricular (RV) function as a result of myocardial and haemodynamic factors. Although the long-term effects of mitral commissurotomy are well known, the aim of this study was to evaluate the immediate impact of percutaneous mitral commissurotomy (PTMC) on RV function in patients with MS. Twelve female patients (mean age 29 +/- 7 years) with isolated rheumatic MS, all in sinus rhythm, were studied before and 24-48 h after PTMC. Multiple parameters of global and longitudinal RV function were assessed by conventional and tissue Doppler imaging echocardiography. Immediately following PTMC, mitral valve area increased from 0.91 +/- 0.29 cm(2) to 1.86 +/- 0.43 cm(2) (P < 0.0001) and RV outflow tract fractional shortening (RVOTfs) increased from 57 +/- 15% to 72 +/- 12% (P = 0.002). There was a significant decrease in systolic pulmonary artery pressure from 46.4 +/- 32.1 mmHg to 29.1 +/- 13.4 mmHg (P = 0.02), in the RV Tei index from 0.44 +/- 0.025 to 0.29 +/- 0.17 (P = 0.021), in myocardial acceleration during isovolumic contraction (IVA) at the lateral tricuspid annulus from 0.36 +/- 0.11 m/s(2) to 0.25 +/- 0.07 m/s(2) (P = 0.023), and in isovolumic contraction velocities at the lateral tricuspid annulus from 11.03 +/- 3.37 cm/s to 8.50 +/- 2.04 cm/s (P = 0.034). In contrast, tissue Doppler velocities at the septal tricuspid annulus remained unchanged. The RV Tei index correlated with systolic pulmonary artery pressure before but not after PTMC (r = 0.70, P = 0.01, and r = 0.270, P = 0.053). Immediately after successful PTMC, significant decrease in RV contractility as assessed by IVA was observed whereas other parameters of infundibular and global RV function as assessed by RVOTfs and Tei index showed significant improvement. These discordant results may be related to the relative insensitivity of currently available echocardiography parameters of RV function that are not completely immune to loading conditions. Further work using larger numbers of patients is needed to confirm our findings and to assess their utility in patient follow-up and management.