METHODS AND RESULTS - A total of 25 coronary arteries from 20 patients who underwent baseline and 6-month follow-up optical coherence tomography were included. Arteries were divided into serial 3-mm segments, and plaque characteristics were evaluated in each segment. A total of 145 segments were divided into low-ESS group (ESS <1 Pa) and higher-ESS group (ESS ≥1 Pa) based on baseline computational flow dynamics analyses. At baseline, low-ESS segments had significantly thinner fibrous cap thickness compared with higher-ESS segments (128.2±12.3 versus 165.0±12.0 μm; P=0.03), although lipid arc was similar. At follow-up, fibrous cap thickness remained thin in low-ESS segments, whereas it significantly increased in higher-ESS segments (165.0±12.0 to 182.2±14.1 μm; P=0.04). Lipid arc widened only in plaques with low ESS (126.4±15.2° to 141.1±14.0°; P=0.01). After adjustment, baseline ESS was associated with fibrous cap thickness (β, 9.089; 95% confidence interval, 2.539-15.640; P=0.007) and lipid arc (β, -4.381; 95% confidence interval, -6.946 to -1.815; P=0.001) at follow-up.

CONCLUSIONS - Low ESS is significantly associated with baseline high-risk plaque phenotype and progression to higher-risk phenotype at 6 months.

CLINICAL TRIAL REGISTRATION - URL: http://www.clinicaltrials.gov. Unique identifier: NCT01110538.

© 2017 American Heart Association, Inc.