['Insulin resistance has been implicated as an important initiating factor in coronary atherosclerosis. However, associations between insulin resistance and specific morphologic features of atherosclerotic coronary arteries remain unclear. We ultrasonographically evaluated the morphologic features of atherosclerotic coronary arteries in nondiabetic patients with insulin resistance.', 'Before intervention, 90 patients with 105 culprit lesions underwent intravascular ultrasound examination through which vessel area, lumen area and plaque area were evaluated. Expansive remodeling (lesion vessel area more than 5% greater than at the proximal reference segment) and constrictive remodeling (lesion vessel area more than 5% less than at the distal reference segment) were also evaluated. Insulin resistance was determined by homeostasis model assessment and defined as values above the 75th percentile (that is, 1.71).', 'Insulin-resistant patients numbered 23, while nonresistant patients numbered 67. Culprit lesions in the insulin-resistant group showed larger vessel area (18.16 +/- 6.94 compared with 13.64 +/- 4.28 mm, P = 0.0001) and plaque area (16.64 +/- 6.78 compared with 12.05 +/- 4.12 mm, P = 0.0001) and more frequently showed expansive remodeling (56% compared with 14%, P < 0.0001) and calcific plaque (33% compared with 12%, P = 0.01). Multivariable logistic regression analysis identified only insulin resistance (odds ratio, 4.9, P = 0.008) as an independent predictor of expansive remodeling.'] Is insulin resistance in nondiabetic patients associated with expansive remodeling in coronary arterial lesions?