Introduction: Endovascular therapy (ET) has emerged as the standard of care for large vessel occlusion (LVO) acute ischemic stroke (AIS) following the positive outcomes from multiple recent randomized trials. This has resulted in an increase in the number of LVO AIS patient transfers to comprehensive stroke centers (CSC). Not all transfers result in ET, and futile transfers may overload CSCs with poor cost benefit ratio. Thus an analysis of the major reasons to forego ET is warranted.
Hypothesis: The major causes to forego ET in LVO AIS patients transferred for treatment in an metropolitan setting are a product of the local stroke systems of care and causes that may be mediated with appropriate imaging and EMS triage protocols will be identified.
Methods: A retrospective analysis of data prospectively collected data between January 1, 2015, and July 31, 2017 was performed on 171 patients whom were transferred from outside hospitals (OSH) to a CSC in a metropolitan area. Of these patients, 63 (37%) were deemed ineligible for ET. The causes to forego ET in these patients were identified and cross referenced with factors that could be changed such as imaging protocols, transfer times, and proximity to a CSC.
Results: The major causes to forego ET were established infarct due to intra-transfer ASPECTS decay (36%) and no LVO (29%). Other causes included: patient too mild or clinically improved (22%), post-tPA hemorrhage (5%), outside time window or randomized to medical management (3%), and other, such as heart attack, seizure, or gastrointestinal bleed (5%). Of the no LVO cohort, 14/18 patients (78%) had no CTA imaging until CSC arrival. The established infarct cohort had a median OSH arrival to CSC arrival time interval of 165 minutes (IQR=130-229.5). Proximity to a CSC from the OSHs in the study ranged from 1 to 9.6 miles with a travel time of 7 to 30 minutes.
Conclusions: Development of established infarct and no LVO were major causes of no ET for transfer patients. These can be mediated by stroke system changes to minimize patient transfers, such as EMS triage to CSC for LVO, with minimal impact on initial arrival time in this urban setting. In addition, the implementation of timely computed tomography angiography (CTA) imaging at OSHs should help reduce futile transfers.