Epicardial Fat and Coronary Artery Calcification in Patients on Long-Term Hemodialysis

Introduction: Recent studies have shown a significant correlation between increased epicardial fat volume (EFV) and mortality, coronary artery disease events, and measures of coronary atherosclerotic burden, for example, coronary calcium. Patients with chronic kidney disease on hemodialysis have an increased prevalence of coronary atherosclerosis and coronary calcium. The mechanisms underlying both may differ from patients with normal kidney function. Only limited data are available on the relationship between epicardial fat and coronary calcium in these patients. Methods: Ninety-three consecutive patients (62 men and 31 women; mean age, 55 +/- 11 years) with chronic kidney failure on regular hemodialysis underwent computed tomography for coronary calcium scoring as well as assessment of cardiovascular risk factors. Calcium scoring was performed using a low-dose, prospectively ECG-triggered high pitch spiral acquisition protocol (dual-source computed tomography, 280-millisecond (ms) rotation, 2 x 128 x 0.6-mm collimation, 120-kV tube voltage, 80-mA.s tube current). Cross-sectional images were reconstructed with 3.0-mm thickness, 1.5-mm increment, and a medium sharp reconstruction kernel (B35f). Agatston score and EVF were analyzed in a semiautomatic fashion using dedicated software. Results: The mean duration of dialysis was 5.7 years. Of all patients, 93% had arterial hypertension, 66% had hyperlipidemia, 30% were diabetic, and 49.5% were current or prior smokers. The mean body mass index (BMI) was 27 +/- 4 kg/m(2). The mean EFV was 162 +/- 80 mL, and the mean coronary artery calcification (CAC) was 765 +/- 1391 Agatston units (AU). In univariable and multivariable analysis, EFV was significantly correlated to BMI (P < 0.05) and age (P = 0.021), but not to CAC (P = 0.106). In subanalysis for values binned by median, we also found a significant correlation between EFV (binned) and smoking (P = 0.49) as well as a significant correlation between EFV (binned) and CAC for 46 patients younger than 55 years (median age). Conclusion: The epicardial fat volume in patients with chronic kidney disease and on hemodialysis is significantly correlated to BMI, age, and smoking but, with the exception of younger patients, not to the coronary calcium score. Our data suggest that in this special patient cohort, other mechanisms might influence the genesis of coronary calcification.