Background:
Nonalcoholic fatty liver disease (NAFLD) is an obesity-related condition with high cardiovascular morbidity. NAFLD patients often have echocardiographic features of left ventricular (LV) diastolic dysfunction. In a large population-based cross-sectional sample of black and white adults free from prevalent liver or heart disease, we tested the hypothesis that NAFLD is associated with subclinical myocardial dysfunction independent of BMI or visceral adipose tissue (VAT).
Methods:
Participants from the Coronary Artery Risk Development in Young Adults study (Y25 exam; age 43-55 years) with concurrent CT quantification of liver fat and tissue Doppler echocardiography with myocardial strain measured by speckle tracking were included (n=2,572). NAFLD was defined as liver attenuation ≤ 40 Hounsfield units after exclusion of other causes of liver fat (medication/alcohol use). Linear regression models were used to test associations.
Results:
NAFLD prevalence was 9.9%. NAFLD participants were more likely to be male (57.1% vs. 41.5%), white (57.5% vs. 50.6%), and had higher BMI (36.3 vs. 29.8 kg/m2) and VAT (222.4 vs. 120.5 cm3) than non-NAFLD. Those with NAFLD also had lower e’ tissue velocity (10.8 vs. 11.9 cm/s), lower E/A ratio (1.2 vs. 1.3), and higher E/e’ ratio (8.4 vs. 7.7). Increased LV mass, left atrial area, LV relative wall thickness, and cardiac output (CO) were present in NAFLD. Global longitudinal strain was also worse in NAFLD (-14.2% vs. -15.2%, all p<0.05). In multivariable analyses adjusted for demographics, health behaviors and BMI, the associations of NAFLD with markers of subclinical myocardial dysfunction were attenuated but remained significant (Table 1). Only e’ velocity, LV mass and CO remained significant after adjustment for VAT. Effect modification by race and sex was not statistically significant.
Conclusion:
NAFLD is associated with subclinical myocardial dysfunction independent of BMI. Attenuation of the relationship by VAT supports the hypothesis that VAT may be a marker of NAFLD.
Relation of Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease to Left Ventricular Diastolic Function and Exercise Tolerance
