Abstract 154: Non-Contrast Computed Tomography Based Patient Selection Achieves Similar Outcomes to Advanced Neuroimaging in Late Time Window Endovascular Thrombectomy

Abstract

Background and Aims: Endovascular Thrombectomy (EVT) for anterior circulation large vessel occlusion(LVO) in late time windows (over 6 hours) has been validated. Studies utilised advanced neuroimaging to select patients with small ischaemic cores. We have evaluated if routine imaging with non-contrast CT (NCCT) is inferior to CT Perfusion (CTP) to select patients for EVT in late time windows. Method: A prospectively maintained database of all EVT patients at two tertiary referral centres was retrospectively interrogated to identify anterior circulation LVO patients, with groin puncture times over 6 hours from symptom onset or time last seen well. Subjects were divided into those that underwent CTP in addition to routine NCCT and CT angiography (CTA) and those that were selected by NCCT/CTA alone. Results: A total of 85 patients were included, 39 (46%) had CTP (CTP+). No significant difference between baseline characteristics of CTP+ vs CTP- groups such as age (mean 66 vs 74, p=0.26), gender (male 49% vs 59%, p=0.36), median ASPECT (8 vs 8, p=0.84) and median NIHSS (13 vs 13, p=0.42) were observed. The two groups were also well matched with respect to time metrics including onset to imaging time (mean 519 vs 477 mins, p=0.41), time to groin puncture (mean 733 vs 690 mins, p=0.90) and procedure time (mean 41 vs 38 mins, p=0.94). No significant difference between early neurological recovery (36% vs 44%, p=0.48), 90 day mean utility weighted mRS (6.2, 95% CI [5.1, 7.4] vs 6.4, 95% CI [5.2, 7.5] p=0.75), rates of functional independence at 90 days (60% vs 64%, p=0.76), and rates of symptomatic haemorrhage (8 vs 9%, p=0.41) was observed between the groups. Conclusion: In late time windows, anterior circulation LVO patients selected for EVT based on routine imaging had non-inferior outcomes to those who underwent CTP. Our data suggests that late time window patients who do not have access to advanced neuroimaging should not be excluded from EVT.