Abstract P401: Subocclusive and Occlusive Intracranial Thrombi in Acute Ischemic Stroke

Abstract

Background: Non-occlusive thrombus in an intracranial artery in acute ischemic stroke is an uncommon occurrence. We compared the clinical course and outcome of intracranial subocclusive to occlusive thrombi. Methods: We conducted a review of patients who presented with acute ischemic stroke and received CT angiogram at a single comprehensive stroke center from January 2018 to December 2019. Patients with intracranial subocclusive thrombus were compared to a control group with complete occlusion matched for occlusion location. Subocclusive thrombus was reviewed by two raters on CT angiography, disagreement resolved by consensus. Patient and stroke characteristics and the clinical course were analyzed. Neurological deterioration was defined as an increase in NIH Stroke Scale (NIHSS) score > 4 compared from baseline to 48 hours. Good outcome at discharge was defined as modified Rankin Score of ≤2. Results: Among 1151 acute ischemic strokes, there were 896 patients with CT angiograms. Sixteen out of 896 (1.8%) patients had intracranial subocclusive thrombus. Thirty-two with comparable intracranial occlusions were identified. In the subocclusive group, 3 of 16 (19%) of received acute endovascular intervention, compared to 13 of 32 (41%) in the occluded group. Sex, median age or time from last known well to hospital arrival did not differ between the two groups. The subocclusive thrombus group had less severe strokes, with median NIHSS score at arrival 3 compared to 8.5 in the occlusion group (p<0.01) and median NIHSS at discharge 1 compared to 5.5 in the occlusive group (p<0.01). Frequency of neurological deterioration in hospital did not differ between the subocclusive and occluded groups at 48 hours (15% vs 15% p=1.00). The subocclusive group was associated with a good outcome at discharge, OR 0.5.71, 95% confidence interval 1.41-23.1. Conclusion: Intracranial subocclusive thrombus in acute ischemic stroke has a more mild presentation compared to complete intracranial occlusion without a high rate of neurological deterioration.