The axial distribution of lesion-site atherosclerotic plaque components: an in vivo volumetric intravascular ultrasound radio-frequency analysis of lumen stenosis, necrotic core and vessel remodeling.

Radio-frequency intravascular ultrasound (IVUS) analysis characterizes atherosclerotic plaques into necrotic core (NC), dense calcium (DC), fibrofatty (FF) and fibrotic (FI) tissue. We studied axial plaque component distribution with respect to stenosis and remodeling. Preintervention virtual histology (VH) IVUS was performed in 81 pts (90 de novo lesions: 43 left anterior descending artery [LAD] and 47 right coronary artery [RCA]). VH-IVUS at the reference, minimum lumen area (MLA) and maximum NC (MaxNC) sites were analyzed. Pullback length of 31.1 +/- 12.0 mm spanned a lesion length of 13.8 +/- 9.5 mm. The MaxNC site was located at the MLA in 3.3% of lesions, proximal to the MLA in 61% of lesions (by 4.11 mm) and distal to the MLA in 35.6% of lesions (by 3.56 mm). The %DC was greater at the MaxNC and %FI and %FF plaque were less than at the MLA site. Lesion fiberoatheromas (FAs) were more often detected at the MaxNC than the MLA (96% versus 51%) and were more often classified as thin-caped or multilayered than the MLA sites. The remodeling index was larger at the MaxNC than MLA sites and correlated with the NC area both at the MLA (r(2) 0.068, p = 0.013) and at the MaxNC (r(2) 0.074, p = 0.009). In conclusion, grey-scale and VH-IVUS analysis showed that the MLA is rarely at the site of greatest instability (largest NC and remodeling) and necrotic core on VH is correlated with remodeling index. These in vivo findings are consistent with previously reported histopathologic data and have important implications for the detection and treatment of coronary artery disease.