RESUMO
BACKGROUND: Symptomatic carotid disease due to thromboembolism has been associated with acute plaque instability and intraplaque haemorrhage. These features may be influenced by the fragility and position of plaque neovessels. The purpose of this study was, therefore, to determine whether any association existed between neovessel density, position, morphology and thromboembolic sequelae. METHODS: Carotid endarterectomy (CEA) samples were collected from 15 asymptomatic patients with greater than 80 per cent stenosis and from 13 patients with greater than 80 per cent stenosis and symptoms within 30 days of CEA. Groups were matched for sex, age, risk factors and plaque size. Samples were stained with haematoxylin and eosin, and Van Gieson stains. An endothelial-specific antibody to CD31 was used for immunohistochemistry. Plaques were assessed for histological characteristics while neovessels were counted and characterized by size, site and shape. RESULTS: There were more neovessels in plaques (P < 0.00001) and fibrous caps (P < 0.0001) from symptomatic than asymptomatic patients. Symptomatic plaque neovessels were larger in size (P < 0.004) and more irregular in shape. There was a significant increase in plaque necrosis and rupture in symptomatic plaques. Plaque haemorrhage and rupture were associated with more neovessels within the plaque (P < 0.02, P < 0. 001) and fibrous cap (P < 0.05, P < 0.004). Patients with preoperative or intraoperative embolization had more plaque and fibrous cap neovessels (P < 0.03, P < 0.001). CONCLUSION: Symptomatic carotid disease is associated with increased neovascularization within the atherosclerotic plaque and fibrous cap; these vessels appear larger in size, more irregular in shape and may contribute to plaque instability and onset of thromboembolic events.
