Objective To explore the classification of collateral blood compensation pathways and collateral blood compensation characteristics in patients with common carotid artery occlusive disease.Methods The hemodynamie and imaging data of 20 patients with common carotid artery occlusive disease,admitted to our hospital from May 2016 to September 2018,were collected.The patients were classified according to whether they had internal carotid artery stealing and collateral circulation compensating for collateral flow.Results Internal carotid artery hematoma was found in 11 of the 20 patients;there was collateral circulation in 17 patients,including 10 branches of the anterior communicating artery,9 branches of the posterior communicating artery,11 branches of the posterior cerebral artery-middle cerebral arterial pia anastomosis,and 8 branches of the ocular artery.There were three types of collateral blood compensation pathways to be discovered in the 20 patients with common carotid artery occlusive disease;type Ⅰ (n=3) was the collateral blood compensation pathway with simple internal carotid artery stealing,type Ⅱ (n=8) was the collateral blood compensation pathway with internal carotid artery stealing and collateral circulation,and type Ⅲ (n=9) was the collateral blood compensation pathways with simple collateral circulation.Conclusion In some patients with common carotid artery occlusion,the internal carotid artery stealing route exists in the collateral flow compensation.

Objective:To explore the clinical characteristics of unilateral vertebral artery V4 segment occlusive lesions (severe stenosis or occlusion), where the contralateral vertebral artery can be compensated through blood flow and reverse supply to the posterior inferior cerebellarartery (PICA).Methods:This study is a retrospective case series of 66 patients with V4 segment occlusive lesions of unilateral vertebral artery diagnosed and treated from June 2020 to October 2022. Patient data were retrospectively collected, and their hemodynamic characteristics and imaging data were analyzed.Results:Of the 66 cases, 11 patients (16.7%) with V4 segment occlusive disease showed the blood flow of the vertebral artery on the opposite side of the lesion on the digital subtraction angiography (DSA), which can be reverse stolen to the posterior inferior cerebellar artery of the diseased side through the confluence point of the vertebrobasilar artery through the distal end of the ipsilateral vertebral artery V4. Owing to the lack of literature on this pathway and based on the characteristics of previous definitions of subclavian artery steal and carotid artery steal, we referred to this pathway as the vertebral artery V4 segment steal. In 6 patients (9.1%), transcranial Doppler ultrasound (TCD) and transcranial color Doppler ultrasound (TCCD) showed that the blood flow signal was not detected at the proximal end of the V4 segment of the affected side, rather the blood flow direction was reversed at the distal end of the V4 segment, resulting in compensatory acceleration of the blood flow velocity of the V4 segment of the contralateral vertebral artery.Conclusion:“V4 segment steal of vertebral artery” is a very rare route of vertebral artery steal. When V4 segment of the vertebral artery is occluded, clinicians should pay attention to observe the blood supply of PICA and whether there is such a steal route, to better evaluate the blood flow compensation and prognosis of patients.