['Narrowing of lumen in atherosclerotic lesions is determined not solely by accumulation of plaque but also by constrictive or expansive vascular remodeling. Underlying mechanisms and determinants of these bidirectional processes are not known.', 'To elucidate the response of vascular remodeling to progressive atherosclerosis by analyzing its potential association with composition of plaque.', 'Seventy patients with 77 de-novo coronary artery lesions underwent intravascular ultrasound imaging before coronary intervention. Target lesions were defined as soft, fibrous/mixed, and calcified plaques. Quantitative measurements of area of lumen (A(L)), total area of vessel (A(TV)) and area of plaque (A(P) = A(TV)-A(L)) were performed at the lesion site and at the proximal and distal reference sites. Remodeling was determined by using a remodeling index [I(R) = (stenosis of A(TV)/mean reference A(TV)) x 100].', 'Overall vascular remodeling was balanced with a mean remodeling index of 100.2+/-19.3% and a high interlesion range (60.2-152.4%). The remodeling index for soft lesions was significantly higher than those for fibrous/mixed and calcified lesions (110+/-18.8 versus 96.2+/-14.4 and 85.9+/-15.1%, P < 0.01). Calcified lesions exhibited lower remodeling indexes than did uncalcified lesions (85.9+/-15.1 versus 104.6+/-18.4%, P < 0.01).'] Is vascular remodeling in atherosclerotic coronary arteries affected by plaque composition?