The Stockholm Stroke Triage Project: Outcomes of Endovascular Thrombectomy Before and After Triage Implementation.

Abstract

The Stockholm Stroke Triage System (SSTS) is a prehospital algorithm for detection of endovascular thrombectomy (EVT)-eligible patients, combining symptom severity assessment and ambulance-to-hospital teleconsultation, leading to a decision on primary stroke center bypass. In the Stockholm Region (6 primary stroke centers, 1 EVT center), SSTS implementation in October 2017 reduced onset-to-EVT time by 69 minutes. We compared clinical outcomes before and after implementation of SSTS in an observational study. We prospectively recruited patients transported by Code Stroke ambulance within the Stockholm region under the SSTS, treated with EVT during October 2017 to October 2019, and compared to EVT patients from 2 previous years. shift in modified Rankin Scale (mRS) scores, mRS score 0 to 1, mRS score 0 to 2, and death (all 3 months), National Institutes of Health Stroke Scale (NIHSS) score change 24-hour post-EVT, recanalization (Thrombolysis in Cerebral Infarction 2b-3), and symptomatic intracranial hemorrhage. mRS outcomes were adjusted for age and baseline NIHSS. Patients with EVT in the SSTS group (n=244) were older and had higher baseline NIHSS versus historical controls (n=187): median age 74 (interquartile range, 63-81) versus 71 (61-78); NIHSS score 17 (11.5-21) versus 15 (10-20). During SSTS, median onset-to-puncture time was 136 versus 205 minutes (P<0.001). Adjusted common odds ratio for lower mRS in SSTS patients was 1.7 (95% CI, 1.2-2.3) versus controls. During SSTS, 83/240 (34.6%) versus 44/186 (23.7%) reached 3-month mRS score 0 to 1 (P=0.014), adjusted common odds ratio 2.3 (95% CI, 1.4-3.6). Median NIHSS change 24-hour post-EVT was 6 versus 4 (P=0.005). Differences in Thrombolysis in Cerebral Infarction, symptomatic intracranial hemorrhage, and death were nonsignificant. With an onset to arterial puncture time reduction by 69 minutes, outcomes in thrombectomy-treated patients improved significantly after region-wide large artery occlusion triage system implementation. These results warrant replication studies in other geographic and organizational circumstances.