Abstract P243: Myocardial Contraction Fraction, Diabetes, and Heart Failure: The Multi-Ethnic Study of Atherosclerosis

Abstract

Background: Persons with diabetes mellitus (DM) have altered cardiac structure and function, which increases heart failure (HF) risk. Myocardial contraction fraction (MCF) is an echocardiographic global measure of fractional shortening recently applied to cardiac MRI. We sought to determine if MCF differed by DM status and if MCF predicts HF in the Multi-Ethnic Study of Atherosclerosis, a cohort which enrolled ethnically diverse adults aged 45-84 who were free of clinical CVD. Methods: Analyses included 4991 with MRI data for whom DM status could be ascertained. Left ventricle (LV) volumes and mass (LVM) were calculated by the summation of disks method from cine short axis images. Ejection fraction (EF) is defined as LV stroke volume (SV) / end diastolic luminal volume. MCF is defined as LV SV/ end diastolic myocardial volume. DM was defined as using hypoglycemic drugs or a fasting glucose>125mg/dl. Linear regression was utilized for cross sectional analyses of the association between MCF and DM status, adjusting for age, gender, race/ethnicity, BMI, systolic BP, BP drugs, and smoking. Cox proportional hazards modeling was used to compare MCF, EF and LV mass quartiles as predictors of HF, adjusting for the above variables and DM. Results: At baseline the mean age was 61.5 (SD 10), 52% were female, 39% white, and 61% minorities; 13% had impaired fasting glucose (IFG) and 12% DM. The table indicates LV measurements. After adjustment, DM status remained associated with a lower MCF (IFG -0.02, 95% CI -0.03,-0.01; DM -0.032, 95%CI -0.04, -0.02). There were 96 incident HF events. Compared to the 4 th quartile, the 1 st MCF quartile was associated with HF (adjusted HR 2.2; 95%CI 1.13, 4.43) as was 1 st EF quartile (adjusted HR 2.9; 95%CI 1.6, 5.2) and 4 th quartile LVM (adjusted HR 5.4; 95%CI 2.2, 13.2). Among those with DM, 39% were in the 1 st MCF quartile, compared to 27% in the 1 st EF and 33% in the 4 th LVM quartile. Conclusions: Incident HF is predicted by MCF. MCF may be a more sensitive marker for diabetic cardiomyopathy than EF or LVM. Ventricular Measures by Diabetes Status Glucose Category Parameter Normal 100-125 mg/dl Diabetes p-value MCF 0.66 (0.14) 0.61 (0.14) 0.59 (0.14) <0.001 EF, % 69 (7) 69 (8) 68 (9) 0.11 SV (ml) 87 (20) 86 (19) 86 (19) 0.05 LMV (g) 142 (38) 153 (41) 157 (43) <0.001 Mean (Std Dev)