Changes in Right Ventricle Function After Mitral Valve Repair Surgery

Background Right ventricular (RV) dysfunction can occur after cardiac surgery and persist for years. We assessed perioperative RV systolic function in patients undergoing mitral valve (MV) repair and further compared minimally invasive robotic-assisted mitral valve repair (MIMVr) vs standard 'open' MV repair (MVr). Speckle tracking (RV free wall strain [RVS]) was used as a sensitive echocardiography method to assess RV function. Methods Retrospective analysis, over 3 years, of consecutive patients (n =158) referred to Mayo Clinic (Rochester, MN, USA). Preoperative, pre-discharge and 1 year transthoracic echocardiograms were reviewed. A prospective pilot study was performed for sample size estimation. Primary outcome was RV free wall strain (RVS). Results Right ventricular free wall strain declined after MV repair surgery (-22.6 +/- 7%(R) vs -15 +/- 6%(R), p < 0.001). There were smaller reductions in RVS in MIMVr vs MVr group (-6.0 +/- 9% vs -103 +/- 8%, p < 0.01), which persisted after adjusting for baseline values (RVS treatment effect 1.5%, p = 0.007). There was greater recovery in MIMVr vs MVr group at 1 year follow-up vs pre-surgery values (-3.4 +/- 9% vs -8.1 +/- 8% respectively, p < 0.001, RVS treatment effect 1.7%, p = 0.001). Bypass time was higher in the MIMVr group (80 min +/- 22 vs 40 min +/- 20, p < 0.0001). The echo findings remained significant correcting for age, pulmonary pressures and change in ejection fraction. Conclusions Right ventricular systolic dysfunction is common after MV repair surgery. Deterioration in RV contraction is less pronounced following MIMVr vs MVr and is associated with enhanced RV functional recovery at 1 year, albeit not to preoperative levels. This may potentially be associated with clinical functional improvement but further studies are warranted to investigate this.