Stroke etiologic subtype may influence the rate of hyperdense middle cerebral artery sign disappearance after intravenous thrombolysis

Disappearance of hyperdense middle cerebral artery sign (HMCAS) on non-contrast brain computed tomography (CT) scan is a reliable sign of arterial recanalization after intravenous (IV) thrombolysis for ischemic stroke. We aimed to assess whether stroke etiologic subtype may influence the rate of HMCAS disappearance and the clinical outcome after IV thrombolysis. We conducted a retrospective analysis of data prospectively collected from 1031 consecutive stroke patients treated with IV thrombolysis. Outcome measures were HMCAS disappearance on follow-up CT scan within 22-36 h of IV thrombolysis, neurologic improvement (NIH Stroke Scale [NIHSS] ≤4 points from baseline or NIHSS score of 0) at 7 days, and modified rankin scale (mRS) ≤1 at 3 months. Of 256 patients with HMCAS on admission CT scan, 125 had a cardioembolic stroke, 67 a stroke due to large-artery atherosclerosis (LAA), 58 a stroke of undetermined etiology, and six a stroke secondary to carotid artery dissection. HMCAS disappearance occurred in 145 (56.6 %) patients, neurologic improvement in 122 (55.0 %) patients, and mRS ≤1 in 64 (32.8 %) patients. Compared with cardioembolic stroke patients, patients with stroke due to LAA had lower odds ratios (OR) for HMCAS disappearance (OR 0.29, 95 % CI 0.15-0.58, p < 0.001), neurologic improvement (OR 0.42, 95 % CI 0.22-0.82, p = 0.011), and mRS ≤1 (OR 0.18, 95 % CI 0.06-0.52, p = 0.002). No significant differences in outcome measures were found between cardioembolic strokes and strokes of undetermined etiology. This study suggests that stroke due to LAA is associated with lower rates of HMCAS disappearance, neurologic improvement, and mRS ≤1 after IV thrombolysis, compared with cardioembolic stroke.