General Anesthesia (GA) and Mitral Regurgitation
GA has been proved to down grade the severity of MR due to its unloading effect on the LV[21-23]. In addition, the severity of MR may vary as the result of the dynamic nature of intraoperative conditions[4]. MR is a valvular pathology affected by multiple variables such as preload, LV contractility, heart rhythm, afterload, GA and positive pressure ventilation[24,25].Alijandro G, et al. had done a experiment that a baseline intraoperative TEE examination was performed after GA induction to observe the effects of GA put on the grade of mitral regurgitation. They thought the reduction in MR severity was particularly pronounced when the regurgitation was due to insufficient leaflet coaptation (annular dilatation/ventricular dilatation), but did not seem to decrease when the regurgitation was due to a flail leaflet[26]. Regurgitation associated with abnormal MV structure is not significantly influenced by GA induction[24,27,28]. Functional MR is shown to be improved with GA when compared with its preoperative severity[29,30]. Although the pharmacologic simulation of hemodynamics in awake-state has been improved, the undervaluation of MR under GA has not been completely eliminated[24,31]. This is particularly challenging in functional MR cases, because there may be significant inconsistencies between the pre- and intraoperative MR severity assessments[31,32].