Abstract 11862: Differences of Histological and Clinical Characteristics Between Fresh and Matured Thrombus in Acute Coronary Syndrome
Background: Unexpectedly, older thrombus was occasionally found in thrombectomy samples from patients with acute coronary syndrome (ACS). To clarify relevance between thrombus maturity and clinical findings, we employed immunohistochemical staining for thrombectomy samples.
Methods: Tissue samples of 200 ACS patients were examined. In 97 samples were from right coronary (RCA), 79 from left anterior descending and/or left main trunk (LAD/LMT), and 24 from left circumflex (LCX). The total thrombus size, white thrombus size (platelets and fibrin), and red thrombus size (red blood cells and fibrin) were measured. The maturity of thrombus was classified into fresh (F group; <1day) and matured (M group; >1 days). Additionally, immunohistochemical staining for CD66b expressed on activated neutrophils, CD68 on macrophages, p-selectin on activated platelets, and tissue factor (TF) were performed.
Results: In 128 (64%) samples were classified into F group, 72 (36%) were M group. Age, gender, short term mortality (until 30 days), presence of hypertension, diabetes mellitus and dyslipidemia revealed no significant differences between two groups. In pathological examination, total thrombus size and red thrombus size of F group were significant larger than M group. (p<0.0001, p<0.01, respectively). However, there is no difference in white thrombus size between two groups. In RCA, thrombus was larger (p<0.001) and percentage of F group was significantly higher (p=0.04) than that of LAD/LMT or LCX. In immunohistochemical observation, leukocytes were aggregated especially in the periphery of the p-selection positive activated platelets appeared on the boundary between white and red thrombi. In this area, number of leukocytes (P<0.001) and CD66b positive cells (p<0.05) were significantly larger in F group. TF positive leukocytes were observed in immigrated leukocytes, and CD66b/TF double positive cells were observed by immunodouble staining.
Conclusion: Thrombus proliferation after plaque disruption sometimes proceeds gradually. Maturity of thrombus was relevant to thrombus size and coronary location. Degree of immigration and activation of circulating leukocytes with TF expression seemed to be involved in this process.
- © 2011 by American Heart Association, Inc.