Serial optical coherence tomography imaging of ACS-causing culprit plaques

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Medical Imaging

Background:

• Acute coronary syndrome (ACS) is often caused by complications within atherosclerotic plaques.
• Understanding plaque healing mechanisms is crucial for managing ACS and preventing recurrent events.
• Optical coherence tomography (OCT) is a high-resolution imaging modality for in-vivo plaque characterization.

Purpose of the Study:

• To elucidate the repair mechanisms of plaque complications leading to ACS.
• To compare plaque healing in ruptured fibrous cap (RFC) versus intact fibrous cap (IFC) lesions.
• To assess plaque evolution in the absence of stent implantation.

Main Methods:

• Serial OCT imaging was performed in the acute phase and during follow-up (1-7 months).
• Ten culprit plaques from patients with ACS (STEMI and NSTEMI) were analyzed.
• Plaques were categorized as RFC (n=5) or IFC (n=5) and were not treated with stenting.

Main Results:

• At follow-up, RFC plaques exhibited a persistent cavity with smooth margins, resembling baseline morphology.
• IFC plaques showed a smoothened intimal border and evidence of organizing thrombus incorporation.
• These findings were observed in both ST-segment elevation myocardial infarction (STEMI) and non-STEMI cases.

Conclusions:

• Following acute thrombosis resolution, RFC plaques heal by maintaining a cavity lined by neointima.
• IFC plaques demonstrate partial incorporation of thrombus into the plaque structure.
• OCT provides insights into the distinct reparative processes of different plaque morphologies post-ACS.