Occurrence and prognostic significance of cervical pseudodissection phenomenon associated with acute intracranial internal carotid artery occlusion

BACKGROUND: Acute stroke from intracranial internal carotid artery (ICA) occlusion can occasionally resemble angiographic cervical ICA dissection which may cause delays in endovascular acute ischemic stroke treatment. OBJECTIVE: To determine the angiographic characteristics of the phenomenon of "pseudodissection" and its clinical implications in acute ischemic stroke endovascular treatment. MATERIAL AND METHODS: Retrospective analysis of angiographic and clinical data from 31 patients with ischemic acute stroke secondary to intracranial ICA occlusion, treated with endovascular therapy at two University-affiliated institutions, was performed. Pseudodissection was defined as angiographic appearance of typical cervical ICA dissection with evidence of normal inner vascular wall upon further catheter exploration. RESULTS: Angiographic appearance pseudodissection was identified in 7 out of 31 patients (22.6%). Six patients had guide catheters placed proximal to pseudodissection in anticipation of stent placement for treatment of ICA dissection. All 7 patients had further exploration of the presumed dissected segment (6 microcatheter, 1 diagnostic catheter) which demonstrated normal vascular inner wall. The clot was located more commonly in the petro-cavernous segment in the pseudodissection patients (5/7, 71%). Carotid terminus clot was more common in ICA occlusion patients than pseudodissection patients (18/24, 75% vs. 2/7, 29% respectively, P < 0001). Recanalization was less common in pseudodissection patients compared to ICA occlusion patients (3/7 and 21/24 respectively, P = .029). CONCLUSION: Early recognition of pseudodissection in the ICA is important in the setting of acute ischemic stroke to avoid delay in treatment of intracranial ICA occlusion.