Plaque vulnerability at non-culprit lesions in obese patients with coronary artery disease: Frequency-domain optical coherence tomography analysis

Background: Obesity is associated with adverse atherosclerotic cardiovascular events. While various metabolic abnormalities associated with obesity promote plaque formation, the morphological phenotype of atherosclerotic plaque has not been well characterized in the setting of obesity. Frequency-domain optical coherence tomography (FD-OCT) enables in vivo visualization of plaque microstructures associated with vulnerability. We characterized plaque microstructures in obese patients. Methods: FD-OCT imaging was performed in 308 patients with coronary artery disease undergoing percutaneous coronary intervention. Patients were stratified according to the presence or absence of obesity (body mass index > 30 kg/m(2)). Plaques in obese (n = 129) and non-obese (n = 179) patients were compared with regard to clinical characteristics and FD-OCT-derived features of plaque vulnerability. Results: Obese patients were more likely to be younger (p = 0.01), female (p = 0.01) and have a history of hypertension (p = 0.01). Higher levels of triglyceride (p < 0.0001) and glucose (p = 0.02), whereas a lower level of high-density lipoprotein cholesterol (HDL-C) (p = 0.02) was observed in obese patients. FD-OCT imaging demonstrated thinner fibrous caps (85.3 +/- 31.1 vs 110.1 +/- 32.4 mm, p = 0.01) and a higher prevalence of thin-cap fibroatheroma (28.8 vs 14.3%, p = 0.01) in obese patients, which remained significant after controlling for differences in clinical characteristics. Achieving a low-density lipoprotein cholesterol (LDL-C) level < 1.8 mmol/l was associated with thicker fibrous caps in obese patients, but only to the level observed in non-obese patients with suboptimal lipid control. Conclusions: Obese patients harbor more vulnerable plaques in association with atherogenic risk factors. The limited benefit of lipid control suggests the need to adopt novel anti-atherosclerotic strategies in higher-risk patients.