Simplified classification of cavernous internal carotid artery tortuosity: a predictor of procedural complexity and clinical outcomes in mechanical thrombectomy

Thromboaspiration catheters are increasingly used for the endovascular treatment of large vessel stroke (LVS), while tortuous vascular anatomy still remains one major challenge in mechanical thrombectomy. Prompt assessing and understanding cavernous internal carotid artery (cICA) tortuosity may help to predict procedural complexities of mechanical thrombectomy and thus improve the clinical outcomes.A retrospective review was performed on a cohort of LVS patients with thromboaspiration catheter. Simplified classification of cICA tortuosity was applied by measurement of the angle of the posterior genus (P) and the height from the peak of the posterior genu to the trough of the anterior genu (D). Statistical analyses were performed to analyze differences among the obtained types of cICA tortuosity regarding procedural characteristics and clinical outcomes.A total of 150 patients with LVS proximal to the internal ICA terminus and middle cerebral artery (MCA) were included in this study, and three types of cICA tortuosity were defined by the simplified classification. The index, such as patients ages and hypertension, procedural fluoroscopy time, the degree of cICA tortuosity, first-pass success, final reperfusion, and 90-day mortality showed significant differences among the three types (P < 0.05), while 90-day good outcome (mRS 0-2) only presented significant difference between Type I and Type III (P < 0.05).The study indicated that the grading of cICA tortuosity is highly correlated with procedural complexity and clinical outcome in mechanical thrombectomy. The proposed classification system may be helpful in pre-procedure prognostication complexity and clinical outcomes.Abbreviations:LVS: large vessel stroke; cICA: cavernous internal carotid artery; mRS: modified Rankin Scale; AIS: acute ischemic stroke; MCA: middle cerebral artery; M1: first division of middle cerebral artery; M2: second division of middle cerebral artery; M3: third division of middle cerebral artery; TICI: Thrombolysis In Cerebral Infarction; TICI 2b: two-thirds of occluded territory reperfusion; DSA: digital subtraction angiography; FT: fluoroscopy time.