Abstract T P40: Pre-Treatment Hyperdense Middle Cerebral Artery Sign Predicts the Outcome of Intra-Arterial Thrombectomy for Acute Stroke

Abstract

Background: Intra-arterial (IA) mechanical thrombectomy has an excellent recanalization rate but does not always correlate with good clinical outcomes. We aimed to investigate whether the location and length of hyperdense middle cerebral artery sign (HMCAS) on pre-intervention Non-Enhanced CT (NECT) can predict IA therapy outcome for acute stroke. Methods: Data were abstracted from our Hyperacute Ischemic Stroke database. Patients with occlusion in ICA, MCA or MCA M2 branches who underwent IA therapy were included. HMCAS was retrospectively analyzed. The length and location of HMCAS on NECT was retrospectively analyzed. Based on the location, HMCAS was categorized into four groups: Proximal HMCAS: hyperdensity within the proximal half of M1 MCA; Distal HMCAS: hyperdensity at the distal half of M1; Full length HMCAS; and Hyperdense M2. The first three groups were referred as M1 HMCAS. Results: Among 126 patients who underwent IA treatment, 64 (51%) had M1 HMCAS, 11 (9%) had hyperdense M2, and 51 (40%) had no HMCAS (No HMCAS group). There was no difference between these two groups in pre-treatment stroke severity, infarct volume, and recanalization rate defined on post intervention cerebral angiogram (p>0.05). There were no differences between M1 HMCAS and No HMCAS groups in favorable outcome defined as modified Rankin scale score 0-2 at 30 days (21% versus 30%, p=0.29, see figure). For those with HMCAS, functional outcome was associated with the location of HMCAS. Favorable 30 day outcome was most frequent in Distal HMCAS (39%), followed by hyperdense M2 (27%), HMCAS proximal (11%), and HMCAS full length (0%, p=0.0053). Conclusion: For acute ischemic stroke due to large vessel occlusion, the lack of HMCAS on NECT does not predict favorable outcome after IA therapy. Among those with hyperdense vessel sign, proximal and longer HMCAS predicts unfavorable outcome. 1