Impact of atherosclerotic plaque components and their distribution on stent deployment: an intravascular-ultrasound virtual histology observational study.

BACKGROUND: The aim of this study was to evaluate how the spatial distribution of each plaque element, defined by intravascular-ultrasound virtual histology (IVUS-VH), may affect stent deployment even at high inflation pressures. METHODS: Thirty-two patients undergoing direct percutaneous coronary intervention and IVUS were evaluated. Fifty-two lesions were treated with drug-eluting stents. Pre-stenting lumen area and real (Rcssla) and average cross-sectional stent lumen area (Acssla) were measured along the whole lesion. Ideal cross-sectional stent lumen area (Icssla) was calculated. Plaque composition was characterized by IVUS-VH. The spatial distribution of each plaque element was quantified by a novel image analysis tool measuring the area and percentage of each plaque component that was adjacent to the lumen. Average stent deployment was defined as: [1 - (Icssla-Acssla)/Icssla]×100%. RESULTS: Stent expansion was significantly less at the site of maximum calcification compared to the average stent deployment (80±9% vs. 85±13%, P=0.044, respectively). Furthermore, wherever calcium was adjacent to the lumen, stent expansion was impaired compared to sites where calcium was non-luminal (70±23% vs. 80±9%, P=0.01, respectively). In contrast, at the site of maximum necrotic core, stent deployment showed a trend to be less compromised, compared to the average stent deployment. CONCLUSIONS: An interaction was found between plaque components and their distribution and stent deployment even at high inflation pressures.