Abstract TP111: Outcomes After thrombolysis of Acute Ischemic Stroke Patients With M2 Occlusion

Introduction: The American Heart Association Stroke Guidelines recommend intra-arterial therapy (IAT) for acute ischemic stroke with large vessel occlusions involving the internal carotid and proximal middle cerebral artery, but the role of IAT for M2 occlusions is unclear. We sought to report the outcomes of acute ischemic stroke patients with M2 occlusions who received intravenous tissue plasminogen activator (IVtPA). Methods: Among 322 acute ischemic stroke patients who received IVtPA from July 1, 2016 to July 1, 2017, we identified 23 patients (7%) with imaging-confirmed M2 occlusions. Two patients with M2 occlusions who underwent IAT were excluded. Data was abstracted on demographics, time of Last Known Normal (LKN), National Institutes of Health Stroke Scale (NIHSS), neuroimaging, clinical presentation, and 90-day modified Rankin Scale (mRS). Good outcome was defined as 90-day mRS of < 2. Results: Among the 21 ischemic stroke patients who received IVtPA for M2 occlusions, the mean age was 64.3 years (range, 21 to 88) and 10 (48%) were male. IVtPA was administered from LKN at a mean 2.5 hours (range, 0.8 to 5.1). Most patients (90%) were transferred from outside facilities. Initial NIHSS prior to IVtPA was a mean of 11.2 (range, 3 to 29). All patients had CT angiogram which was done at a mean of 4.0 hours from LKN (range, 1.2 to 7) and showed 10 (48%) right-sided and 11 (52%) left-sided M2 occlusions. Most (20/21) had CT perfusion, which was done at a mean of 4.1 hours from LKN (range, 1.2 to 7.3) and all showed mismatch in the corresponding territory of the arterial occlusion. MRI brain was performed in 19/21 patients at a mean of 21 hours from LKN (range, 3 to 53) and restricted diffusion in the corresponding arterial territory was seen in 17 (89%). Discharge NIHSS was a mean of 8.1 (range, 0 to 24). Among 20 patients with 90-day mRS data available, good clinical outcome was seen in 7 (35%). Conclusions: Among acute ischemic stroke patients with M2 occlusions, good clinical outcome was seen in only 35%, despite receiving IVtPA. Further studies are warranted to investigate the potential role of IAT in improving the natural history of medically treated acute ischemic stroke with M2 occlusions.