Coronary artery remodelling is related to plaque composition

Objective: To assess the potential relation between plaque composition and vascular remodelling by using spectral analysis of intravascular ultrasound (IVUS) radiofrequency data. Methods and results: 41 coronary vessels with non-significant (<50% diameter stenosis by ;angiography), <= 20 mm, non-ostial lesions located in non-culprit vessels underwent IVUS interrogation. IVUS radiofrequency data obtained with a 30 MHz catheter, were analysed with IVUS virtual histology software. A remodelling index ( RI) was calculated and divided into three groups. Lesions with RI >= 1.05 were considered to have positive remodelling and lesions with RI <= 0.95 were considered to have negative remodelling. Lesions with RI >= 1.05 had a significantly larger lipid core than lesions with RI 0.96 - 1.04 and RI <= 0.95 ( 22.1 ( 6.3) v 15.1 ( 7.6) v 6.6 (6.9), p< 0.0001). A positive correlation between lipid core and RI ( r = 0.83, p< 0.0001) and an inverse correlation between fibrous tissue and RI ( r = 20.45, p = 0.003) were also significant. All of the positively remodelled lesions were thin cap fibroatheroma or fibroatheromatous lesions, whereas negatively remodelled lesions had a more stable phenotype, with 64% having pathological intimal thickening, 29% being fibrocalcific lesions, and only 7% fibroatheromatous lesions ( p< 0.0001). Conclusions: In this study, in vivo plaque composition and morphology assessed by spectral analysis of IVUS radiofrequency data were related to coronary artery remodelling.