Comparison between perfusion- And collateral-based triage for endovascular thrombectomy in a late time window

Background and Purpose-Perfusion-based triage has proven to be effective and safe for selecting patients who are likelyto benefit from endovascular thrombectomy (EVT) in a late time window. We investigated collateral-based triage forEVT in patients presenting beyond 6 hours, in terms of interrater reliability and efficacy in predicting clinical outcome,in comparison to perfusion-based triage.Methods-One hundred and thirty-two patients who underwent both computed tomographic angiography and computedtomography perfusion for anterior circulation large artery occlusion 6 to 24 hours after last seen well were enrolled.Patients were classified into EVT-eligible and EVT-ineligible groups according to perfusion- and collateral-based triages.We evaluated the interrater reliability of collateral-based triage and differences in good outcome rates of patients whoreceived EVT in the EVT-eligible groups based on perfusion- and collateral-based triages.Results-Both computed tomographic angiography and computed tomography perfusion were assessable in 93 patients.Seventy-six patients were eligible for EVT according to perfusion-based triage. Among them, EVT was performed in58, of whom 32 (55.1%) had good outcome. Sixty-nine patients were eligible for EVT based on collateral-based triage.Among them, EVT was performed in 50 patients, of whom 31 (62.0%) had good outcome. Interrater reliability ofcollateral-based triage was good (generalized ?=0.73 [95% CI, 0.59-0.84]). Agreement on EVT eligibility betweenperfusion- and collateral-based triages was moderate (?=0.41 [95% CI, 0.16-0.61]). There was no difference in goodoutcome rates of patients who underwent EVT in the EVT-eligible groups based on perfusion- and collateral-basedtriages (55.1% versus 62.0%; P=0.0675).Conclusions-Collateral-based triage showed good interrater reliability and comparable efficacy to that of perfusion-basedtriage in predicting clinical outcome after EVT in patients presenting beyond 6 hours. Collateral-based triage is a reliableapproach for selecting patients for EVT in the extended therapeutic time window.