[Characterization of atherosclerotic plaque in patients with unstable angina pectoris and stable angina pectoris by optical coherence tomography].

OBJECTIVE: To compare the characterization of coronary atherosclerotic plaques in patients with unstable angina pectoris (UAP) and stable angina pectoris (SAP) by optical coherence tomography (OCT).

METHODS: OCT was performed in 47 patients (23 UAP and 24 SAP) undergoing coronary angiography. Lipid-rich plaque (defined by > or = 2 quadrants of the cross-section area), thin cap fibroatheroma (TCFA), thickness of fibrous cap, plaque rupture, calcification and thrombus visualized by OCT were compared between UAP and SAP patients.

RESULTS: OCT imaging was successfully in 44 out of 47 patients (22 UAP, 22 SAP). Proportion of lipid-rich plaques was similar between UAP and SAP groups [91% (20/22) vs. 73% (16/22), P = 0.741]. The minimum thickness of fibrous cap in the UAP group was significantly thinner than that in SAP group [(69.5 +/- 34.7) microm vs. (141.1 +/- 68.5) microm, P = 0.000] and the rate of fibrous cap erosion in the UAP group was significantly higher than that in the SAP group [59% (13/22) vs. 9% (2/22), P = 0.000]. Percents of TCFA [73% (16/22) vs. 14% (3/22), P = 0.000] and plaque rupture [50% (11/22) vs. 9% (2/22), P = 0.003] were significantly higher in UAP group compared those in SAP group. Incidence of thrombus and calcification were similar between two groups.

CONCLUSIONS: OCT imaging can clearly define plaque characterization of coronary atherosclerosis. UAP patients have thinner fibrous cap, higher incidences of fibrous cap erosion, plaque rupture and TCFA compared patients with SAP.