Left ventricle volume affects the result of mitral valve surgery for idiopathic dilated cardiomyopathy to treat congestive heart failure

Background. Mitral valve surgery is a recommended treatment for congestive heart failure; however, its effect for idiopathic dilated cardiomyopathy ( DCM) with an extremely enlarged left ventricle ( LV) is not well documented. We examined our long-term results of mitral valve surgery for idiopathic dilated cardiomyopathy. Methods. Fifty-five patients of idiopathic dilated cardiomyopathy have undergone mitral valve surgery to treat intractable congestive heart failure since 1998. Forty-two patients were male with an average age of 55. Preoperative New York Heart Association functional class was III in 25, IV in 30, and 19 were dependent on inotropic infusion. The mitral valve was repaired in 37 patients and replaced in 18. The tricuspid valve was repaired in 35 patients and replaced in 3. We divided 46 elective cases into two groups by LV end-systolic volume index. Results. Postoperatively, an intraaortic balloon pump was required in 2 patients and a left ventricular assist device in 1; both were emergent cases. Hospital mortality was noted 4.3% in elective cases ( 2 of 46) and 14.5% in overall cases ( 8 of 55). One-year, 3-year, and 5-year survival rate of elective cases was 73.3%, 58.2%, and 51.7%, respectively. Left ventricle size has decreased and LV contractility has increased in a small LV group year by year, but those in a large LV volume group have not changed subsequently after surgery. There was a significant difference noted in the survival rate of the two groups divided by LV end-systolic volume index. Conclusions. Mitral valve surgery for idiopathic dilated cardiomyopathy to treat end-stage heart failure is relatively safe and effective in elective status. However, isolated mitral reconstruction without any other type of surgery may not suffice for an extremely enlarged LV.