Abstract 2544: Longitudinal Distribution of Lipid Pools in Coronary Plaques Evaluated by Three-dimensional Integrated Backscatter Intravascular Ultrasound (3D IB-IVUS)
Background: We previously developed an Integrated Backscatter Intravascular Ultrasound (IB-IVUS) for tissue characterization of coronary plaques. The relationship between the longitudinal spread of lipid pool and coronary plaque morphology has not been investigated in the clinical setting.
Methods: Forty-four plaques with moderate stenosis in 37 patients were evaluated by three-dimensional (3D) IB-IVUS at every 1 mm between 5 mm distal and 5 mm proximal from the minimal lumen site (MLS). Vessel area of MLS, remodeling index, eccentricity rate, plaque burden, plaque volume and % lipid volume (lipid volume/plaque volume) were measured at the same time.
Results: The % lipid volume was correlated with eccentricity rate (r = 0.35, p = 0.02). The % lipid area at MLS was correlated (r > 0.70, p < 0.05) with that at a site within 3 mm proximal and within 2 mm distal. Seventy percent of the maximum lipid areas were located between MLS and 4 mm proximal site from the MLS. Among 21 plaques with lipid pools, 76 % (16 sites) of the vessel areas increased at the sites between MLS and 4 mm proximal site from the MLS. The maximum remodeling index site of the vessel area shifted 2.1 mm proximal from the MLS. That is, lipid cores shift proximal from the MLS.
Conclusion: This is the first clinical demonstration of the relationship between the longitudinal spread of lipid pool and coronary plaque morphology. The longitudinal gap between MLS and vessel area expansion site is one of the features of plaques with lipid pools. This localization may determine the site of plaque rupture of coronary arteries. 3D IB-IVUS is a promising method for the longitudinal evaluation of tissue characterization of coronary plaques.