O-004 Utilization of CT perfusion based patient selection for mechanical thrombectomy beyond the 7-hour window: a comparison of functional outcomes and complications

Background Since the advent of intra-arterial (IA) therapy for acute ischemic stroke, patient selection has been largely driven by time based criteria, significantly limiting the number of patients deemed eligible for IA therapy. However emerging data suggests that image based criteria may be useful for selecting patients for IA interventions. The purpose of this study was to directly compare functional outcomes and hemorrhage rates of patients treated within a 7-h window with those treated beyond this benchmark when CT perfusion was used as the primary triage tool. Methods We retrospectively analyzed a prospectively collected database including all acute ischemic stroke patients who received IA therapy for acute ischemic stroke at the Medical University of South Carolina, regardless of time from symptom onset. At presentation CTP maps were qualitatively assessed for presence of penumbra and infarction. Selected patients underwent IA therapy. Functional outcome per the modified Rankin scale circa 90 days was determined in the clinic by a stroke neurologist. Patients unable to return to clinic were interviewed by phone. Patients were subdivided into groups before and after 7 h as it is within the suggested conventional 6–8 h time based treatment window and was the median time for our population. Results 140 patients were included in the study, however 11 of these were lost to follow-up by 90 days. The median time from symptom onset to groin access in all patients was 7.0 h. Overall, 28 patients (20%) had bleeding complications, however only 10 (7.1%) were symptomatic. The average NIHSS for patients treated within 7 h was 17.3 and 30.2% had a good outcome at 90 days (mRS 0–2). Patients treated beyond 7 h had an average NIHSS of 15.1 in and mRS 0–2 in 45.5% of those treated beyond 7 h (p=0.XXX). An additional 17.5% and 12.1%, respectively, were functionally independent with minimal disability (mRS=3) at 90 days. There was a substantial difference in hemorrhage rate with 26.1% of patients demonstrating hemorrhage on post op CT in patients treated within 7 h, compared with only 14.1% of those treated beyond 6 h (p=0.YYY). Conclusion Patients treated beyond 7 h had improved rates of good functional outcomes, return to independent living, symptomatic ICH and mortality to those treated within a 7-h time window, suggesting CTP allows safe selection of patients, especially those outside of conventional time parameters. Our findings suggest that endovascular reperfusion in acute ischemic stroke may be performed safely and effectively beyond a 7-h time window. This implies potential eligibility of patients for IA intervention who would otherwise be denied this potentially highly beneficial therapy based on time criteria. Competing interests A Turk: Penumbra. J Magarik: None. E Nyberg: None. M Chaudry: None. R Turner: None.