Acute Occlusion of the Distal Internal Carotid Artery : Single Center Experience in 46 Consecutive Cases, review of the literature and proposal of a classification.

PURPOSE: The acute distal intracranial occlusion of the internal carotid artery (ICA) is a very complex heterogeneous pathology, characterized by various patterns. Aim of this work is to identify the different types and propose a classification.

METHODS: Among the patients admitted for stroke in the anterior circulation from august 2014 to October 2017, 46 (25%) presented with intracranial distal carotid artery occlusion. The mean age of the patients was 71 (SD 13.7), 65,2% female. The protocol included general and specific neurological examinations, CT, CT-Angiography with multiphase CTA, followed by Angiography. The occlusion was treated by aspiration device alone or associated with stent-retriever. NIHSS at the admission, at discharge and modified ranking Scale (mRS) at four months were examined.

RESULTS: The occlusions presented with various patterns. Depending on its site (located at the distal ICA bifurcation or more proximal at the level of the ophthalmic segment of ICA, with or without extent to ICA bifurcation) taking also into account the various involvement of the cerebral vessels and anatomic variations of Circle of Willis, three groups of occlusion types could be identified (T1, T2 and T3). The collateral circulation, and the possibilities of the endovascular revascularization important for the final outcome, were clearly connected with the type of occlusion. NIHSS at admission was 19.1 (Range from 8 to 30, SD 4.4). Good outcome defined as mRS 0-2 at for months was obtained in 17 patients (37%).

CONCLUSIONS: The proposed classification reproduces more precisely the complexity and heterogeneity of this pathology, being useful in the diagnosis and treatment of these patients.