. On the other side, it has been demonstrated that the risk of adverse acute cerebrovascular events, besides being related to the characteristics of the plaque, such as softness, subintimal haemorrhage or surface ulcer, is strictly related to the actual residual lumen of the internal carotid artery. The pre-eminent role of the percentage of stenosis in the choice of the treatment, hence, presumes a narrow range of variation of the original calibre of the vessel, yet to be proven.