Objectives: The purpose of this study was to prospectively investigate the effects of surgical correction of mitral regurgitation (MR) on exercise performance, cardiac function and neurohormonal activation.
Background: Little is known about the effect of surgical correction of MR on functional status or on neurohormonal activation.
Methods: Cardiopulmonary exercise test, radionuclide angiography and blood samples for assessment of neurohormonal status were obtained in 40 patients with nonischemic MR before and within one year (216+/-80 days) after surgery. Twenty-four patients underwent mitral valve repair (MVr), and 16 underwent valve replacement (VR) with anterior chordal transection.
Results: Despite an improvement in New York Heart Association functional class, exercise performance did not change (peak oxygen consumption: 19.3+/-6.1 to 18.5+/-5.6 ml/kg/min, percentage of maximal predicted oxygen consumption: 79.5+/-18.2% to 76.8+/-16.9%). After surgery, left ventricular (LV) ejection fraction (EF) decreased (64.2+/-10.3% to 59.9+/-11.4%, p = 0.003) while right ventricular (RV) EF increased (41.4+/-9.6% to 44.7+/-9.5%, p = 0.03). Left ventricular EF did not change after MVr (64.3+/-11.5% to 61.5+/-12.2%), but RVEF improved (40.4+/-9.2% to 46.0+/-10.0%, p = 0.02). In contrast, VR was associated with an impairment of LV function in the apicolateral area and a decrease in LVEF (64.1+/-8.5% to 57.4+/-10.0%, p = 0.01), whereas RVEF did not change (42.9+/-10.3% to 42.8+/-8.6%). Moreover, there was only a slight decrease in neurohormonal activation after surgery.
Conclusions: Despite an improvement in symptomatic status, exercise performance was not improved seven months after either MVr or VR for MR, and neurohormonal activation persisted. Compared with MVr, VR resulted in a significant impairment of cardiac function in this study.