Epicardial fat volume is associated with coronary microvascular response in healthy subjects: a pilot study
Résumé
Epicardial fat (EF) is an active ectopic fat depot, which has been associated with coronary atherosclerosis, and which could early influence endothelial function. We thus investigated the relationship between EF and endothelium-dependent vasoreactivity of the coronary microcirculation, in highly selected healthy volunteers. Myocardial blood flow (MBF) was determined by measuring coronary sinus flow with velocity-encoded cine magnetic resonance imaging (MRI) at 3T. We measured MBF at baseline and in response to sympathetic stimulation by cold pressor testing (CPT) in 30 healthy volunteers with normal left ventricular (LV) function (age 22 +/- 4 years, BMI = 21.3 +/- 2.8 kg/m(2)). EF volume was volumetrically assessed by manual delineation on short-axis views. CPT was applied by immersing one foot in ice water for 4 min. Mean EF volume was 56 +/- 26 ml and mean LV mass 100 +/- 28 g. CPT significantly increased heart rate (HR) by 32 +/- 19%, systolic blood pressure by 14 +/- 10%, and rate-pressure product by 45 +/- 25%, P < 0.0001. The increase in HR, reflecting sympathetic stimulation, was not influenced by sex, age or EF volume. CPT induced a decrease in coronary vascular resistance (135 +/- 72 vs. 100 +/- 42 mm Hg.ml(-1).min.g, P = 0.0006), and a significant increase in MBF (0.81 +/- 0.37 vs. 1.24 +/- 0.56 ml.min(-1).g(-1), P < 0.0001). Interestingly, we found a significant negative correlation between EF volume and DeltaMBF (r= - 0.40, P = 0.03), which remained significant after adjusting for DeltaHR. DeltaMBF was also associated with adiponectin (r = 0.41, P = 0.046), but not with waist circumference, BMI, C-reactive protein, lipid or glycemic parameters. In multivariate analysis, adiponectin and EF volume remained both independently associated with DeltaMBF. A high EF amount is associated with a lower coronary microvascular response, suggesting that EF could early influence endothelial function.
Mots clés
Adolescent
Adult
Blood Pressure/*physiology
Cold Temperature/diagnostic use
Coronary Artery Disease/*etiology/physiopathology
Coronary Circulation/*physiology
Coronary Vessels/physiology
Endothelium
Vascular/*physiology
Female
Humans
Male
Microcirculation/physiology
Pilot Projects
Reproducibility of Results
Ventricular Function
Left/*physiology
Young Adult