Risk Factors for Distal Clot Migration during Mechanical Thrombectomy of Anterior Circulation Large Vessel Occlusion

Abstract

Introduction: Distal clot migration (DCM) is a known complication of mechanical thrombectomy (MT), but neither risk factors for DCM nor ways of how it might affect clinical outcomes have been extensively studied to date. Methods: To identify risk factors for and outcomes in the setting of DCM, the records of all patients with acute ischemic stroke due to anterior circulation large vessel occlusion (LVO) treated with MT at a single center between May 2016 and June 2018 were retrospectively reviewed. Uni- and multivariable analyses were performed to evaluate predictors of DCM and good functional outcome (90-day modified Rankin Scale; mRS 0–2). Results: A total of 65 patients were included, DCM was identified in 22 patients (33.8%). Patients with DCM had significantly higher pre-procedural intravenous tissue plasminogen activator (IV-tPA) administration (81.8 vs. 53.5%, p = 0.03), stentrievers thrombectomy (95.5 vs. 62.8%, p = 0.006), and longer median puncture to recanalization time (44 [34–97] vs. 30 [20–56] min, p = 0.028) as compared to group with non-DCM. Also, they had lower rates of Thrombolysis in Cerebral Infarction (TICI) 2b/3 recanalization (p = 0.002), higher median National Institutes of Health Stroke Scale (NIHSS) scores at discharge (p = 0.01), and lower rates of 90-day mRS (0–2; 18.2 vs. 48.8%; p = 0.016). On subgroup analysis, patients with middle cerebral artery occlusions who underwent MT with stentrievers <40 mm in length had a higher risk of DCM (p = 0.026). On multivariable analysis, IV-tPA administration (OR; 5.019, 95% CI [1.319–19.102], p = 0.018) and stentrievers thrombectomy (OR; 10.031, 95% CI [1.090–92.344]; p = 0.04) remained significant predictors of DCM. Baseline NIHSS score (OR; 0.872, 95% CI [0.788–0.965], p = 0.008) and DCM (OR; 0.250, 95% CI [0.075–0.866], p = 0.03) were independent predictors of 90-day mRS 0–2. Conclusion: In patients undergoing MT for anterior circulation LVO, DCM is associated with lower rates of TICI 2b/3 recanalization and worse functional outcomes at 90 days. IV-tPA administration and MT with short stentrievers are independent predictors of DCM development.