Angioscopic evaluation of atherosclerotic plaques: Validation by histomorphologic analysis and association with stable and unstable coronary syndromes

Objectives. We validated coronary angioscopic observations with histologic assessment of material removed by atherectomy. Background. Up to now, angioscopic findings have been primarily descriptive, and the clinical significance still needs to be substantiated. The proposed Ermenonville classification is relevant but has not yet been validated by histomorphologic analysis. Methods. We compared angioscopic findings in patients with different coronary syndromes and used atherosclerotic material retrieved by directional coronary atherectomy to validate the angioscopic observations. Coronary angioscopy was performed in 63 patients (56 men, 7 women) with stable (26 patients) and unstable angina (37 patients) before and after directional coronary atherectomy. The identity of atherectomized material was confirmed by ex vivo visualization with the angioscope and by postatherectomy angioscopy. Angioscopic and histologic findings could be compared in 44 of 63 patients. Results. Angioscopic findings were grouped into gray-white and yellow lesions (gray-yellow, deep yellow, yellow-red or yellow-pink). We found that patients with unstable angina had predominantly yellow lesions (89%). In patients with stable angina, gray-white (43%) or yellow (57%) lesions were similarly distributed. Ruptured yellow plaques and red or pink thrombi were identified in 11% of patients with stable angina and 39% of patients with unstable or early postmyocardial infarction angina. Histologically, gray-white lesions represented fibrous plaque without degeneration in 64% and with degeneration in 36% of patients. Gray-yellow lesions were associated predominantly with degenerated plaque (64%) and, to a lesser extent, with fibrous plaque (14%) or atheroma (14%). Deep yellow and yellow-red lesions represented either atheroma (53%) or degenerated plaque (42%). Conclusions. Our study establishes a histomorphologic basis for classification and interpretation of angioscopic findings. Yellow plaque color is closely related to degenerated plaque or atheroma and is associated with unstable coronary syndromes.