Angioscopic Evaluation of Spontaneously Ruptured Aortic Plaques

BACKGROUND Spontaneous ruptured aortic plaques (SRAP), which might cause atheromatous embolization, are thought to be mainly iatrogenic and have not been observed directly. OBJECTIVES The purpose of this study was to clarify the incidence, types, and dimensions of SRAP using angioscopy. METHODS In a cross-sectional study, 324 consecutive patients diagnosed with or suspected of having coronary artery disease were subjected to intra-aortic scans with nonobstructive angioscopy. Samples of SRAP were taken from the aorta. The dimensions of cholesterol crystals of atheromatous materials were measured with a polarizing microscope and compared with those of the ghost images of cholesterol crystals. RESULTS SRAP were detected in 262 patients (80.9%); 120 of 262 patients had ruptured aortic plaques below the diaphragmatic level. Samples were successfully obtained from 96 patients. The detected numbers of atheromatous material, fibrin, macrophage, and calcification were 237 (49.1%), 244 (50.6%), 111 (23.0%), and 127 (26.3%) out of 482 samples, respectively. The median lengths and widths of the sampled plaques were 254 μm (interquartile range IQR: 100 to 685 μm) and 148 μm (IQR: 535 to 423.5 μm), respectively. The lengths and widths of the cholesterol crystals isolated from atheromatous materials were 40 μm (IQR: 32.7 to 53.7 μm), and 30 μm (IQR: 23 to 38 μm), respectively, compared with the respective dimensions of the ghost images of 86 μm (IQR: 53 to 119) and 13 μm (IQR: 7 to 18 μm). No embolic symptoms were observed within 24 h of general care via cardiac catheterization. CONCLUSIONS SRAP are commonly scattered, and their dimensions were smaller than previously recognized. (Detecting Ruptured Aortic Plaques by Nonobstructive Angioscopy; UMIN000029772).