Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke When Multiple Passes Are Required and Associated Risk Factors

Introduction: This study aimed to evaluate the outcomes of mechanical thrombectomy for acute ischemic stroke when multiple passes are required and to identify the associated risk factors. Methods: Consecutive patients with acute ischemic stroke treated with mechanical thrombectomy at the Neurology Department of Ninth People’s Hospital and the Neurosurgery Department of Xinhua Hospital of Shanghai Jiao Tong University School of Medicine from 2013 to 2018 were included. Patients were divided into 2 groups: those who received ≤2 passes and those who received >2 passes. Outcomes of the 2 groups were compared. Multivariate linear regression was used to determine factors associated with the need for >2 passes. All patient data were reviewed retrospectively. Results: A total of 122 patients were included, of whom 83 patients required ≤2 passes and 39 patients required >2 passes. After adjusting for sex, atrial fibrillation history, smoking history, and involvement of middle cerebral artery and internal cerebral artery, the National Institutes of Health Stroke Scale (NIHSS) score was associated with a 1.08-times greater risk of >2 passes (95% confidence interval [CI]: 1.01–1.17), and internal carotid artery with a 5.13-times greater risk of >2 passes (95% CI: 1.02–25.69). Having more than 2 passes was associated with significantly higher 7-day (25.6% vs. 6%), 90-day mortality rates (34.2% vs. 16%) and a significantly lower recanalization rate (66.7% vs. 89.2%). Conclusion: Needing more than 2 passes during mechanical thrombectomy is associated with poorer outcomes. Higher preprocedural NIHSS scores and internal carotid artery thrombi are associated with more than 2 passes.