Thoracic fat volume is independently associated with coronary vasomotion.
OBJECTIVE
Thoracic fat has been associated with an increased risk of coronary artery disease (CAD). As endothelium-dependent vasoreactivity is a surrogate of cardiovascular events and is impaired early in atherosclerosis, we aimed at assessing the possible relationship between thoracic fat volume (TFV) and endothelium-dependent coronary vasomotion.


METHODS
Fifty healthy volunteers without known CAD or major cardiovascular risk factors (CRFs) prospectively underwent a (82)Rb cardiac PET/CT to quantify myocardial blood flow (MBF) at rest, and MBF response to cold pressor testing (CPT-MBF) and adenosine (i.e., stress-MBF). TFV was measured by a 2D volumetric CT method and common laboratory blood tests (glucose and insulin levels, HOMA-IR, cholesterol, triglyceride, hsCRP) were performed. Relationships between CPT-MBF, TFV and other CRFs were assessed using non-parametric Spearman rank correlation testing and multivariate linear regression analysis.


RESULTS
All of the 50 participants (58 ± 10y) had normal stress-MBF (2.7 ± 0.6 mL/min/g; 95 % CI: 2.6-2.9) and myocardial flow reserve (2.8 ± 0.8; 95 % CI: 2.6-3.0) excluding underlying CAD. Univariate analysis revealed a significant inverse relation between absolute CPT-MBF and sex (ρ = -0.47, p = 0.0006), triglyceride (ρ = -0.32, p = 0.024) and insulin levels (ρ = -0.43, p = 0.0024), HOMA-IR (ρ = -0.39, p = 0.007), BMI (ρ = -0.51, p = 0.0002) and TFV (ρ = -0.52, p = 0.0001). MBF response to adenosine was also correlated with TFV (ρ = -0.32, p = 0.026). On multivariate analysis, TFV emerged as the only significant predictor of MBF response to CPT (p = 0.014).


CONCLUSIONS
TFV is significantly correlated with endothelium-dependent and -independent coronary vasomotion. High TF burden might negatively influence MBF response to CPT and to adenosine stress, even in persons without CAD, suggesting a link between thoracic fat and future cardiovascular events.
Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.
Vincent
V
Dunet
Department of Clinical Physiopathology, Lausanne University Hospital, Lausanne, Switzerland.
François
F
Feihl
Department of Clinical Physiopathology, Lausanne University Hospital, Lausanne, Switzerland.
Amin
A
Dabiri
Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.
Gilles
G
Allenbach
Department of Clinical Physiopathology, Lausanne University Hospital, Lausanne, Switzerland.
Bernard
B
Waeber
Center for Investigation and Research in Sleep, Lausanne University Hospital, Lausanne, Switzerland.
Raphaël
R
Heinzer
Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland. john.prior@chuv.ch.
John O
JO
Prior
D052436:Adipose Tissue, White / Q000000981:diagnostic imaging*; D000368:Aged; D003324:Coronary Artery Disease / Q000453:epidemiology*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012307:Risk Factors; D012414:Rubidium Radioisotopes; D013909:Thorax / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D012414:Rubidium Radioisotopes
Endothelial function; Myocardial blood flow; PET; Thoracic fat