Establishment of surgical indication for carotid endareterectomy or carotid stening based on calcification and instability of plaques

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Carotid stenosis is increasing in number in the Japanese population. Some of the carotid stenosis becomes symptomatic and the others remain asymptomatic. For establishment of surgical indication for carotid endarterectomy or carotid stenting, we have analyzed carotid plaques with special interest of calcification and fragile plaques. We routinely used 3D-CT angiography (3D-CTA) for evaluation of carotid stenosis. We therefore tested relation between calcified carotid plaques and surgical pathology and found that partly calcified plaques can be treatable by stenting but whole calcification plaque is hard to treat by stenting. Carotid endarterectomy can handle any of calcified plaques. T o detect intraplaque neovascularization, we immunostained endarterectomy specimens with hypoxia-inducible factor 1 alpha (HIF1-α) and vascular endothelial growth factor (VEGF). The plaques form the symptomatic cases were more stained with HIF1-αand VEGF than asymptomatic cases suggesting plaque hypoxia and neovascularization is an important factor for symptomatic changes. We collected 807 cases of asymptomatic carotid stenosis from 39 institutions in Japan and followed up for two years. We are on the way of collecting the data. At present status, about 50% of the cases was followed for 2 years, and we found that symptomatic rate for asymptomatic cases with medical treatment was 2.4%/year, which is similar to the US study (ACAS) or Britain study (ACST).