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.