AIMS: There is limited in vivo evidence regarding the temporal evolution of non-culprit coronary plaque morphology. We evaluated changes in non-culprit plaque morphology over time by optical coherence tomography (OCT).
METHODS AND RESULTS: 72 patients with 257 non-culprit segments with serial OCT studies were analyzed. Non-culprit 5mm-long coronary segments from the same imaged region were matched between baseline and follow-up. OCT plaque characterization including automated attenuation analysis was performed and changes over a median follow-up of 6.2 months were evaluated. On segment level, lumen area decreased from baseline to follow-up, whereas fibrous cap thickness increased. Similarly, plaque attenuation indexes at follow-up were significantly decreased. Minimal cap thickness per patient did not change. In 68.5% of segments plaque morphology did not change. Favorable change was observed in 18.4% of segments and unfavorable in 12.9%. There were no robust clinical predictors of change in plaque morphology. Attenuation analysis supported the qualitative characterization, showing significantly different attenuation between different plaque types.
CONCLUSIONS: In non-culprit coronary segments of patients with coronary artery disease under standard medical therapy, segment-level but not patient-level minimum fibrous cap thickness increases over time, with observations of both favorable and unfavorable changes in individual segments.