Influence of increased left ventricular myocardial mass on early and late mortality after cardiac surgery.

Background: Increased left ventricular mass (LVM) is a well-recognized predictor of cardiovascular morbidity and mortality in epidemiological studies, but its impact on mortality after cardiac surgery is poorly defined. We hypothesized that patients with increased LVM index (LVMI) were more likely to have greater 30 day and 1 yr mortality.
Methods: With IRB approval, intraoperative transoesophageal echocardiography images of 844 cardiac surgical patients were reviewed. LVMI was calculated using the American Society of Echocardiography recommended formula. Outcome variables studied were 30 day and 1 yr mortality.
Results: Mortality within 30 days occurred in 28 patients (3.3%) and within 1 yr in 91 patients (10.8%). An almost linear relationship was found between increasing LVMI and the risk of mortality within 30 days of cardiac surgery. The odds ratio (OR) of dying within 30 days of surgery was 1.15 (95% confidence interval 1.01-1.31) per 20 g m(-2) increase in LVMI. This finding remained statistically significant in multivariate analysis controlling for the effects of age, weight, gender, surgery type, LV function, and functional status [OR=1.36 (1.11-1.66) per 20 g m(-2) increase]. Increased LVMI was not found to be a statistically significant predictor of 1 yr mortality.
Conclusions: Increased LVMI, but not LV systolic function as measured by the fractional area of contraction (FAC) was identified as a strong independent predictor of perioperative mortality after adult cardiac surgery. The relationship between LVMI and risk of 30 day mortality was nearly linear. Furthermore, decreased FAC, and not LVMI, was a strong independent predictor of 1 yr mortality.