Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

Background and aimsThis study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).Methods and resultsIn 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = −0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = −0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = −0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).ConclusionCoronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.