Influence of pericoronary adipose tissue on local coronary atherosclerosis as assessed by a novel MDCT volumetric method

Abstract

Objective Pericoronary adipose tissue (PCAT) may create a pro-inflammatory state, contributing to the development of coronary artery disease (CAD). We sought to evaluate the feasibility of avolumetric PCAT quantification method using a novel threshold based computed tomography approach. In addition we determined the relation between PCAT volumes and CAD. Methods In 51 patients (49.5±5.1 years, 64.8% male) who underwent 64-slice MDCT, we measured threshold-based PCAT volumes using distance and anatomic-based methods. Using the most reproducible method, we performed the proximal 40-mm distance measurement in three groups as stratified by coronary plaque and high-sensitivity C-reactive protein (hs-CRP) levels: Group 1 (presence of coronary plaque, hs-CRP >2.0 mg/L); an intermediate group (Group 2, no plaque, hs-CRP >2.0 mg/L); and Group 3 (no plaque, hs-CRP<1.0 mg/L). We compared PCAT volumes to the presence of coronary plaque on a patient (n=51) and vessel (n=153) basis. On a subsegment basis (n=1224), we compared PCAT volume to the presence of plaque as well as plaque morphology. Results Distance-based PCAT volume measurements yielded excellent reproducibility with intra-observer intraclass correlation (ICC) of 0.997 and inter-observer ICC of 0.951. On a both a per-patient and per-vessel analysis, adjusted PCAT volume was greater in patients with plaque (Group 1) than without plaque (Group 2 and 3, p<0.001). No difference in PCAT volume was seen between high and low hs-CRP groups without plaque (p=0.51). Adjusted PCAT volumes were higher in subsegments with plaque as compared without (p<0.001). Additionally, adjusted PCAT volume was greatest in subsegments with mixed plaque followed by non-calcified plaque, calcified plaque, and the lowest volume in segments with no plaque (p<0.001). Conclusion In this proof-of-concept study, threshold based PCAT volume assessment is feasible and highly reproducible. PCAT volume is increased in patients and vessels with coronary plaques. Surrounding vessel subsegments with coronary plaque, particularly mixed plaques, have greatest PCAT volume and highlight the effect of local PCAT in the development of coronary atherosclerosis.

Molecular Biology of Atherosclerosis

“…Furthermore, perivascular fat was much more proinflammatory than fat from other sources and showed greatly increased release of TNF-␣, MCP-1 (CCL2), and MIP-1␣ (CCL3) upon high-fat feeding (1135). These findings provide new impetus for controlling weight gain and other factors that may increase deposition of coronary perivascular fat, recently shown to be strongly associated with atherosclerotic plaques in humans (1114,1161,1750).…”

CT-based analysis of pericoronary adipose tissue density: Relation to cardiovascular risk factors and epicardial adipose tissue volume

“…The attenuation thresholds for adipose tissue applied in our study were in concordance with prior studies on pericoronary PCAT assessment using coronary CT angiography: Gorter et al used a threshold of À200 to À30 HU, MaurovichHorvat et al used a threshold of À149 to À30 HU and Mahabadi et al defined all voxels as fat within a window of À195 and À45 HU. 8,13,14,29 Previous studies have shown a decrease in PCAT volume in the course of the coronary arteries from proximal to distal portions. 4,30 Analysis of the overall PCAT density according to the distance from the ostium revealed significantly higher density levels for the proximal segments compared to the more distal sections.…”

“…Given recent evidence that enhanced PCAT volume and thickness is highly associated with atherosclerotic plaque volume in the underlying coronary artery, we included only CTA data sets without coronary atherosclerosis to rule out the influence of atherosclerotic plaque on PCAT density by possible inflammatory imbalances. 7,13,14 However, several external influences may affect the CT attenuation of PCAT, in particular partial volume effects and image interpolation (smoothing) artifacts but also vascularization of PCAT by the contrast-enhanced coronary artery. This should manifest itself through decreasing PCAT density with growing distance from the contrast-enhanced coronary artery lumen.…”

Human perivascular adipose tissue dysfunction as a cause of vascular disease: Focus on vascular tone and wall remodeling

“…EAT thickness (Ahn et al, 2008;Demircelik et al, 2014;Eroglu et 5 al., 2009) and also EAT volume (Mihl et al, 2014;Kaya et al, 2014;Mohar et al, 2014;Groves et al, 2014;Kim et al, 2014) were found to be higher in patients with coronary artery diseases. Total quantity of PVAT around coronary artery is strongly related to atherosclerotic plaque (Mahabadi et al, 2010;Maurovich-Horvat et al, 2011). More recently, extra media thickness has been suggested as a novel index of PVAT and associated with an increasing number of cardiovascular risk factors (Haberka and Gasior, 2015).…”