40. Optical coherence tomography correlates of complex lesions evaluated by coronary angiography in patients with acute coronary syndromes

Plaque rupture (PR) and superimposed thrombosis have been shown as the most frequent underlying substrate in acute coronary syndromes (ACS). Coronary angiography is a luminogram that is not able to define in-vivo features of the culprit plaques. The aim of the study was to use optical coherence tomography (OCT) to investigate the pathology underlying complex (CL) and non-complex angiographic lesions (NCL). Methods: We retrospectively enrolled 107 ACS patients admitted to our institution; 83 with Non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation myocardial infarction (STEMI). Coronary angiography was performed and culprit lesions were classified according to Ambrose criteria into NCL (n = 47) and CL (n = 60). In STEMI patients, angiographic and OCT analysis were performed after mechanical thrombus aspiration. OCT analysis of these culprit lesion was performed to identify plaque morphology; either PR or intact fibrous cap (IFC), as well as the presence of superimposed thrombosis, lipid rich plaque, thin cap fibroatheroma (TCFA), and minimal lumen area (MLA). Results: OCT analysis showed that 58 lesions (54.2%) were classified as PR and 48 lesions (44.9%) were associated with thrombi. Lipid rich plaques were identified in 62 culprit plaques (57.9%). PR, intracoronary thrombi, lipid rich plaques and thin cap fibroatheroma (TCFA) were more frequent in CL compared with NCL (71.7% vs 31.9%, 63.3% vs 21.3%, 71.7% vs 40.4% and 46.7% vs 21.3% respectively). PR (31.9%) with superimposed thrombus (21.3%) may be also detected in NCL. In STEMI patients, there was no significant difference regarding OCT plaque features between NCL and CL. Conclusion: In conclusion, OCT demonstrates PR and thrombosis in the majority of ACS patients presenting with CL. Of note, one third of NCL has PR and thrombosis by OCT. In STEMI, coronary angiography is of limited utility in identifying PR by means of CL and should be implemented with OCT to tailor future therapies.