Background Specific plaque phenotypes that predict a favorable response to statin therapy have not been systematically studied. This study aimed to identify optical coherence tomography predictors for a favorable vascular response to statin therapy. Methods and Results Patients who had serial optical coherence tomography imaging at baseline and at 6 months were included. Thin-cap area (defined as an area with fibrous cap thickness <200 μm) was measured using a 3-dimensional computer-aided algorithm, and changes in the thin-cap area at 6 months were calculated. A favorable vascular response was defined as the highest tertile in the degree of reduction of the thin-cap area. Macrophage index was defined as the product of the average macrophage arc and length of the lesion with macrophage infiltration. Layered plaque was defined as a plaque with 1 or more layers of different optical density. In 84 patients, 140 nonculprit lipid plaques were identified. In multivariable analysis, baseline thin-cap area (odds ratio [OR] 1.442; 95% CI, 1.024-2.031, P=0.036), macrophage index (OR, 1.031; 95% CI, 1.002-1.061, P=0.036), and layered plaque (OR, 2.767; 95% CI, 1.024-7.479, P=0.045) were identified as the significant predictors for a favorable vascular response. Favorable vascular response was associated with a decrease in the macrophage index. Conclusions Three optical coherence tomography predictors for a favorable vascular response to statin therapy have been identified: large thin-cap area, high macrophage index, and layered plaque. Favorable vascular response to statin was correlated with signs of decreased inflammation. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01110538.
Keywords: layered plaque; macrophage; optical coherence tomography; statin; thin‐cap area.