Elevated intraoperative expression of ventricular myosin light chain predicts heart failure after valve replacement surgery.

ABSTRACT

BACKGROUND: It can be difficult to predict which patients will survive and recover cardiac function after valve replacement surgery. We hypothesized that the expression levels of ventricular myosin light chain (MLCv) might reflect the severity of disease or the extent of irreversible myocardial damage and might be useful for predicting the postoperative course. Thus, the aim of this study was to explore the relationship between MLCv expression in specimens obtained during valve replacement surgery and the postoperative New York Heart Association (NYHA) class. METHODS: The levels of expression of the regulatory MLCv (MLC-2v) and MLC-1v in papillary muscle specimens from 80 patients who underwent valve replacement surgery for rheumatic valvular disease were evaluated by Western blot analysis. RESULTS: The patients were similar with regard to the intraoperative expression of MLC-1v, regardless of postoperative NYHA class. The preoperative NYHA class, the end-systolic left ventricular internal dimension, and the intraoperative expression of MLC-2v emerged as independent risks factors for a NYHA class status of III/IV at 6 months after surgery, with an area under the receiver operating characteristic curve of 0.862. CONCLUSION: The intraoperative level of MLC-2v expression was predictive of the patients' NYHA class after valve replacement surgery. This result suggests that future studies evaluating the use of preoperative specimens (such as biopsy or peripheral blood samples) for measurement of MLC-2v levels could lead to a valuable preoperative tool for the assessment of candidates for valve replacement.