P532Visceral and subcutaneous fat predict coronary artery disease in patients with zero calcium score by multi-slice computed tomography coronary angiography

Abstract

Introduction: Although the presence of coronary artery calcium is considered a surrogate for the presence of coronary atherosclerosis; a zero coronary artery calcium score (CACS) does not exclude the presence of coronary atherosclerotic lesions, including vulnerable plaques. Purpose: To detect the value of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated by abdominal computed tomography in the detection of coronary artery disease (CAD) in patients with zero CACS by multi-slice computed tomography coronary angiography (MSCT-CA). Methods: The abdominal muscular wall was traced manually to calculate SAT and VAT areas (cm2) (outside and inside abdominal muscular wall respectively) as well as SAT density [Hounsfield units (HU)] at L4-L5 in 460 consecutive patients referred for evaluation of chest pain by MSCT-CA. Results: 60% of the studied patients (n=275) had zero CACS. Coronary atherosclerotic plaques were noted in 88 patients (32%) (Group 1); fifteen of them (17%) had significant coronary artery affection (≥50% stenosis). The remaining 187 patients (68%) (Group 2) had normal coronaries. There was no statistically significant difference between both groups as regards gender, body mass index, waist circumference, waist- to- hip ratio, history of hypertension, dyslipidemia, smoking status or positive family history of CAD. Group 1 patients had statistically significantly higher age (52.7±8.6 vs. 47.5±10.5 years; p=0.000), diabetes prevalence (37.5% vs. 16.0%; p=0.000), VAT area (142.1±70.7 vs. 107.1±53.0 cm2; p=0.000), VAT/SAT area ratio (0.42±0.20 vs. 0.32±0.19; p=0.000), and denser SAT depot (-100.1±7.2 vs. -102.0±7.1 HU; p=0.047), compared to Group 2 patients. Multivariable regression analysis identified age (OR: 1.05, 95% CI: 1.02- 1.08; p=0.003), diabetes (OR: 2.23, 95% CI: 1.19-4.19; p=0.012), VAT area (OR: 1.01, 95% CI: 1.00-1.01; p=0.030), and SAT density (OR: 0.96, 95% CI: 0.92- 1.00; p=0.038) as independent predictors of coronary artery atherosclerosis in patients with zero CACS. Diabetes was the only variable associated with significant coronary artery affection (p=0.017). Conclusion: Estimation of VAT area and SAT density can be helpful to predict coronary artery atherosclerosis, before the progression into its advanced stage of calcification.