End-systolic volume as a predictor of postoperative left ventricular performance in volume overload from valvular regurgitation

Although over-all cardiac performance may remain normal in patients with left ventricular volume overload from valvular regurgitation, impairment of myocardial function may occur and remain undetected by currently accepted methods of assessing ventricular performance. Since end-systolic volume reflects myocardial contractile function yet is independent of preload, we assessed preoperative end-systolic volume as a measure of myocardial function in 41 patients with aortic regurgitation, mitral regurgitation or both. Preoperative end-systolic volume was compared to postoperative left ventricular performance as measured by postoperative echocardiographic per cent dimension change (% ΔD) and New York Heart Association class. Preoperative end-systolic volume correlated well with postoperative left ventricular performance in patients with aortic regurgitation (r = 0.77) or mitral regurgitation (r = 0.73). Much poorer correlations existed for preoperative ejection fraction, enddiastolic volume or left ventricular end-diastolic pressure. Preoperative end-systolic volume also predicted patients at high risk for perioperative cardiac death, with all such cardiac deaths occurring in patients with an end-systolic volume >60 cc/m². Again, both preoperative ejection fraction and end-diastolic volume were less precise predictors of surgical outcome. Patients with aortic regurgitation appeared to tolerate a larger end-systolic volume better than those with mitral regurgitation.End-systolic volume is an easily determinable parameter of left ventricular function which is independent of the abnormal preload that occurs in mitral regurgitation and aortic regurgitation and appears to provide a measure for the onset of myocardial dysfunction in patients with these lesions. Whether this myocardial dysfunction is due to a depressed inotropic state of individual sarcomeres, a stress-shortening imbalance or to other factors is unknown, but its presence has major prognostic importance.