Thin cap fibroatheroma defined as lipid core abutting lumen (LCAL) on integrated backscatter intravascular ultrasound: Comparison with optical coherence tomography and correlation with peri-procedural myocardial infarction

Background: This study evaluated the ability of a newly developed integrated backscatter intravascular ultrasound (IB-IVUS) system (VISIWAVE, Terumo, Tokyo, Japan) to detect optical coherence tomography (OCT)-verified thin cap fibroatheroma (TCFA) and assessed the correlation with peri-procedural myocardial infarction (PMI) after percutaneous coronary intervention (PCI). Methods and Results: One hundred culprit lesions in 100 consecutive patients with ischemic heart disease who consented to repeated IVUS and OCT prior to PCI were studied. Of 100 lesions, 48 had OCT-verified TCFA with a cap thickness <65 μm. Such lesions had larger percentage lipid area and lipid angle >2 quadrants on IB-IVUS. A lipid core abutting lumen (LCAL) was defined as a lipid core pool in the plaque area, directly contacting with the lumen regardless of its circumferential extension. IB-IVUS-identified TCFA defined as a combination of percentage lipid area ≥53.6%, remodeling index ≥1.03, and the presence of LCAL was the best predictor of OCT-verified TCFA with sensitivity, specificity, positive and negative predictive values, and accuracy of 72.9%, 90.4%, 87.5%, 78.3%, and 82.0%, respectively. IB-IVUS-identified TCFA as well as OCT-verified TCFA were significant independent predictors of PMI, after adjusting for other predictors on multivariate analysis. Conclusions: IB-IVUS can be used to identify plaques with a high prevalence of TCFA. Such techniques can therefore potentially be used to identify lesions with an elevated risk of PMI after PCI.