Abstract 197: Time Dependency and Relationship to Reperfusion Grade in Acute Ischemic Stroke

Background: Time to reperfusion following endovascular treatment (ET) strongly predicts outcomes after acute ischemic stroke (AIS). However, the impact of time may vary depending on the grade of reperfusion. We sought to assess time-outcome relationship within grades of reperfusion in the North American Solitaire Acute Stroke (NASA) registry. Methods: The investigator-initiated NASA registry recruited 24 clinical sites within North America to submit demographic, clinical, site-adjudicated angiographic, and clinical outcome data on consecutive patients treated with the Solitaire Flow Restoration device. We identified patients treated with anterior circulation ischemic stroke treated within 8 hours. The modified Thrombolysis in Cerebral Ischemia (TICI) was used wherein TICI 2 was divided in TICI 2a ( 50% reperfusion). We assessed the impact of time to reperfusion (onset to procedure completion time) on good outcome (modified Rankin Scale 0-2 at 3 months) in those who achieved at least TICI 2a reperfusion, independent of other relevant covariates using logistic regression analysis. We further assessed this relationship within strata of reperfusion grade. Results: Among 265 eligible patients, 209 (78.9%) had complete data (mean age 68.4 years, median NIHSS score 18). Reperfusion grade was as follows: TICI 3: 35.4%; TICI 2b: 39.7%, TICI 2a: 14.8%; TICI 0-1: 10.0%. Independent predictors of outcome at 3 months among those achieving TICI 2-3 reperfusion were: initial NIHSS score, intravenous tissue plasminogen activator use, symptomatic hemorrhage, and time to reperfusion. For each 30 minutes, the adjusted OR for time to reperfusion was 0.874 (95% CI 0.797-958). There was a significant interaction between final TICI grade and 30-minute time to reperfusion intervals (P=0.001) such that the effect of time was strongest in TICI 2a patients. Conclusions: Time to reperfusion is a strong predictor of outcome following ET for AIS with 13% decreased odds of good outcome per 30-minute delay in achieving TICI 2-3 reperfusion. However, the effect varied by TICI grade such that its greatest effect was in those achieving TICI 2a reperfusion.