Diving MCA and First-Pass Effect: A Subgroup Analysis From the ARISE II Study

BACKGROUND: The impact of internal carotid artery tortuosity on achieving first-pass effect in mechanical thrombectomy has been described; however, middle cerebral artery (MCA) tortuosity remains understudied. We investigated the association of MCA tortuosity with radiographic and functional outcome using quantitative and qualitative measures. METHODS: The ARISE II study (Analysis of Revascularization in Ischemic Stroke With EmboTrap) was used to identify patients with anterior circulation stroke. MCA tortuosity was calculated using the Inflection Count Metric by 2 readers blinded to the angiographic/clinical outcomes. The total cohort was trichotomized into 3 groups (A, B, and C) based on M1 tortuosity tertiles, with group A representing the lowest tertile and group C representing the highest tertile. The primary efficacy end point was the achievement of first-pass expanded Thrombolysis in Cerebral Ischemia reperfusion ≥2c. A good functional outcome was defined as a 90-day modified Rankin Scale score of 0 to 2. Baseline and procedural data were compared between groups. RESULTS: A total of 168 patients with M1 or M2 occlusion and measurable MCA tortuosity were identified. Patients in group C were more likely to have renal disease and hyperlipidemia, whereas patients in group A were more likely to have hypertension ( P <0.05). There were no significant differences in the National Institutes of Health Stroke Scale score at presentation or the Alberta Stroke Program Early Computed Tomography Score between groups. First-pass effect was more likely in group A than in groups B and C (51.8% versus 37.5% and 26.8%, respectively; P =0.024). The rate of final expanded Thrombolysis in Cerebral Ischemia reperfusion ≥2c was higher in group A (87.5%) versus in groups B and C (77.8% and 66%, respectively; P =0.026); achieving modified Rankin Scale score of 0 to 2 was more likely in group A (77.8%) versus in groups B and C (74.5% and 52.7%, respectively; P =0.008). There were no differences in distal emboli or symptomatic intracranial hemorrhage. First-pass effect and angiographic outcomes were consistent with standard angle of curvature tortuosity. CONCLUSIONS: Patients with higher MCA tortuosity were less likely to achieve first-pass effect, successful reperfusion, and good functional outcome at 90 days postmechanical thrombectomy for acute ischemic stroke. REGISTRATION: URL: http://clinicaltrials.gov ; Unique identifier: NCT02488915.