Serial optical coherence tomography imaging of ACS-causing culprit plaques.

AIMS: The aim of this study was to understand better the mechanisms of repair of plaque complications causing acute coronary syndrome.

METHODS AND RESULTS: We used OCT in the acute phase and at follow-up (one to seven months) to investigate the plaque healing in 10 culprit plaques: five ruptured fibrous cap (RFC) and five intact fibrous cap (IFC) which were not treated with stent deployment and caused ST-segment elevation myocardial infarction (n=8) and non-STEMI (n=2). At follow-up OCT, the margins of the evacuated cavity in RFC plaques showed a smooth surface and a morphology similar to that of baseline images, while IFC plaques showed a smoothened intimal border and a double layering indicating organising thrombus incorporated in the superficial layers of the plaque.

CONCLUSIONS: In the months following a successfully dissolved acute thrombosis, OCT revealed that the cavity of RFC plaques persists and is bordered by a smooth "neointima", while IFC plaques showed features suggesting partial incorporation of the deepest layers of thrombus in the plaque.