Impact of metabolic syndrome on tissue characteristics of angiographically mild to moderate coronary lesions - Integrated backscatter intravascular ultrasound study

Objectives We assessed the impact of metabolic syndrome (MetS) on the tissue characteristics of coronary plaques using integrated backscatter intravascular ultrasound (IB-IVUS). Background Metabolic syndrome is associated with the increasing risk of cardiovascular disease. Methods We identified MetS by the definition of the National Cholesterol Education Program in Adult Treatment Panel III criterion. Non-target coronary lesions with mild to moderate stenosis were measured by conventional and IB-IVUS parameters using 40-MHz (motorized pullback 0.5 mm/s) intravascular catheter. A total of 20 IB-IVUS images were recorded at an interval of 0.5 mm for 10 mm length in each plaque. The 3-dimensional analyses were performed using commercially available software. Results The prevalence of MetS was 61 patients (50%) with 73 lesions (49%) among 122 patients with 148 lesions. Patients with MetS showed a significant increase in percentage lipid area (38 +/- 19% vs. 30 +/- 19%, p = 0.02) and percentage lipid volume (39 +/- 17% vs. 33 +/- 17%, p = 0.03), and they also showed a significant decrease in percentage of fibrous volume (57 +/- 14% vs. 61 +/- 13%, p = 0.03). Multivariate regression analysis after adjustment for potentially confounding risk factors showed that MetS remains correlated independently with the percentage of lipid volume (r = 0.223, p = 0.01). Logistic regression analysis after adjusting for confounding and non-MetS coronary risk factors showed that MetS (odds ratio 4.00, 95% confidence interval 1.33 to 12.0, p = 0.01) is proved to be an independent predictor of the lipid-rich plaque. Conclusions Metabolic syndrome is associated with lipid-rich plaques, contributing to the increasing risk of plaque vulnerability.