Optical Coherence Tomography Predictors for a Favorable Vascular Response to Statin Therapy

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.