Abstract TP217: Thrombus Migration in Acute Ischemic Stroke Patients Receiving Mechanical Thrombectomy

Background: Thrombus migration is occasionally observed during mechanical thrombectomy in acute ischemic stroke patients. However, the factors influencing migration and its impact on imaging and clinical prognosis remain unclear. We investigated the clinical and imaging predictors of thrombus migration and to evaluate the corresponding outcomes.

Methods: We retrospectively analyzed data from patients with acute anterior circulation (internal carotid artery, M1, M2) stroke who underwent mechanical thrombectomy at two comprehensive stroke centers. Thrombus migration was defined as any distal movement of the proximal end of the thrombus on digital subtraction angiography (DSA) compared to pre-interventional computed tomography (CT) angiography. A comprehensive imaging review was performed, including Alberta Stroke Program Early CT Score, hyperdense vessel sign on non-contrast CT, collateral flow grading on CT angiography and DSA. Univariate and multivariable logistic regression analyses were performed to determine the association between clinical and imaging parameters and thrombus migration. In addition, we compared clinical outcomes according to the presence of thrombus migration.

Results: Of the 365 patients enrolled, thrombus migration was observed in 81 patients (22.2%). In 40 of these, the thrombus migrated beyond the vessel segment. In multivariable analysis, hyperdense vessel sign (adjusted odds ratio [aOR], 5.41; 95% CI 2.9-10.07), older age (aOR, 1.04; 95% CI, 1.01-1.08), and onset-to-image time (aOR 1.00; 95% CI 0.99-1.00) were associated with thrombus migration. In particular, thrombus migration is an independent predictor of first-pass effect (aOR 2.17; 95% CI, 1.15-4.1). However, there was no significant effect on functional outcome as measured by modified Rankin Scale at 3 months.

Conclusions: In large-vessel occlusion stroke, the location of the thrombus may change before mechanical thrombectomy compared to pre-interventional angiographic imaging. The composition of the thrombus, as indicated by the hyperdense vessel sign, may influence its tendency to migrate. While thrombus migration is associated with a first-pass effect, it does not influence functional outcomes.