Association between plaque instability, angiogenesis and symptomatic carotid occlusive disease

Background: Angiogenesis is a recognized feature of the atherosclerotic pro cess and has been described in the context of unstable coronary atheroscler otic lesions. The aim of this study was to assess the association between a ngiogenesis in atherosclerotic carotid plaques and microscopic features of plaque instability, in particular intraplaque haemorrhage. Methods: Consecutive patients undergoing carotid endarterectomy were includ ed. Endarterectomy specimens were divided into their constituent atheroscle rotic lesions. Histological sections were prepared and stained with haemato xylin and eosin, and immunohistochemically with an endothelial cell marker (CD34). The quantity of intraplaque haemorrhage was measured in transverse histological sections using computerized image analysis. Microvessel counts were performed in CD34-stained sections and were verified through computer ized image analysis. Results: Some 239 atherosclerotic lesions from 73 patients were available f or analysis; 73 were early lesions, 74 were raised fibroatheromas and 92 we re unstable atherosclerotic plaques. One hundred and fifty lesions were not haemorrhagic; 89 exhibited intraplaque haemorrhage, of which 28 involved l ess than 50 per cent of the plaque sectional area. There were higher microv essel counts in plaques containing over 50 per cent haemorrhage (P < 0.0001 ), unstable atherosclerotic lesions (P < 0.0001) and atherosclerotic lesion s obtained from symptomatic patients (P < 0.001). Conclusions: There are strong associations between plaque vascularity, quan tity of intraplaque haemorrhage and presence of symptomatic carotid occlusi ve disease.