E-098 Mechanical thrombectomy in the extended 24 hour time window for acute ischemic stroke patients with large vessel occlusion

Introduction In 2018 the AHA guidelines were updated to include expansion of the mechanical thrombectomy (MT) window for acute ischemic stroke (AIS) patients with anterior circulation large vessel occlusion (LVO) from 6 to 24 hours. We report our institution’s clinical experience with the expanded 24 hour MT window. Methods Among 166 AIS patients with LVO who underwent MT from January 1, 2018 to July 1, 2019 at our comprehensive stroke program, we identified 77 patients (46%) with anterior circulation LVO treated in the extended 24 hour time window. Data was abstracted on demographics, time of Last Known Normal (LKN), National Institutes of Health Stroke Scale (NIHSS), CT brain perfusion (CTP), cerebral blood flow (CBF), time to maximum (Tmax), clinical presentation, Thrombolysis in Cerebral Infarction (TICI) score, and outcomes. Symptomatic hemorrhage was defined as neurological worsening within 36 hours accompanied by an NIHSS score increase >4 with correlative imaging. Good functional outcome was defined as 90 day modified Rankin Score of Results Among 77 AIS patients with anterior circulation LVO who underwent MT in the expanded window, the mean age was 66.7 years (range, 26 to 98), 39 (51%) were female, and 69 (90%) were white. Stroke risk factors included atrial fibrillation 48 (62%), diabetes 53 (69%), and hypertension 53 (69%). Only 10 (13%) received intravenous thrombolysis. Initial mean NIHSS was 14.5 (range 1 to 28). CTP was available in 72 (94%) and the mean time from LKN to CTP was 12.0 hours (range, 2.8 – 22.8 hours). CTP mean CBF was 22.8 mL/100 g/min (range, 0 – 157 mL/100 g/min). CTP mean Tmax was 113.6 s (range, 0 to 289 s). Mean time from LKN to MT groin puncture was 12.9 hours (range, 6.1 to 23.5) and 69 (90%) achieved TICI 2B or 3 recanalization. Symptomatic hemorrhage occurred in 5 (6.5%). Fifteen patients (19.5%) expired. Among the 62 patients who survived, the mean discharge NIHSS was 8.8 (range, 0 to 26). Good functional outcome occurred in 19 (24%). Conclusions AIS patients with anterior circulation LVO treated in the expanded 24 hour MT window account for nearly half of our center’s MT volume. Although high revascularization rates and low symptomatic hemorrhage rates were observed similar to the clinical trials, good functional outcome was lower than the trials. Disclosures S. Salam: None. C. Powers: None. S. Nimjee: None. P. Youssef: None. S. Heaton: None. V. Lee: None.