LAUSR

Intraplaque hemorrhage (IPH) is known to play an important role in plaque vulnerability in coronary artery. However, the biological reaction in IPH and clinical features of patients with IPH remain unknown, since most histological studies of IPH in coronary artery were performed on autopsy cases. Directional coronary atherectomy (DCA) enables the direct pathological evaluation of collected tissue from “living” patients. We aimed to clarify the clinical presentations and histopathologic features of IPH using specimens obtained by DCA. This multicentral prospective observational study included consecutive patients who underwent percutaneous coronary intervention for de novo lesions using DCA from June 2015 to February 2018. Histopathological sections that were collected from coronary plaques by DCA were evaluated and classified by the presence of IPH. IPH in DCA specimens was defined as clusters of hemosiderin (Figure A, arrows), erythrocytes (Figure B, arrow heads) and fibrin (Figure C, arrows) within the coronary plaque. A total of 154 de novo lesions from 154 patients were ultimately analyzed, and were divided into IPH group (n=37) and non-IPH group (n=117). Clinical profiles of patients in the two groups were comparable, except that unstable angina rather than chronic coronary syndrome was significantly more prevalent in the IPH group (32.4% vs. 16.2%, P=0.04). Histopathological analysis showed a significantly higher incidence of cellular-rich plaque (46.0% vs. 25.6%, P=0.02) and spindle-shaped cells (18.9% vs. 6.0%, P=0.02), which indicate active cell proliferations, in the IPH group. The prevalence of necrotic core was also higher in IPH group compared to non-IPH group (48.7% vs. 13.7%, P<0.01). Pathohistological analysis revealed that coronary plaques with IPH had an active cell proliferation, and patients with IPH likely to had clinical presentations of unstable angina. Figure 1 Type of funding source: None