Abstract
Background
The Oahu large vessel occlusion (LVO) bypass protocol is a real-world island-wide EMS initiative designed to identify patients with suspected LVOs in the field and triage them directly to a Comprehensive Stroke Center (CSC) for endovascular therapy (EVT).
Methods
A retrospective preimplementation-postimplementation study was conducted to investigate the impact of the bypass protocol on endovascular treatment times and patient outcomes between January 1, 2017 to January 1, 2023.
Results
A total of 351 patients met inclusion criteria (102 patients pre-bypass vs. 249 patients post-bypass). In an interrupted time series analysis, there was a sustained 66-min reduction in onset-to-CSC door time (
p
= 0.0046), and a 41-min reduction in onset-to-reperfusion time (
p
= 0.08) in the post-bypass period with no changes in temporal trends. Interfacility transfers for EVT declined 5-fold (55.9% to 11.6%;
p
p
= 0.13). In multivariate logistic regression modeling, longer onset-to-reperfusion times were independently associated with worse clinical outcomes, where every 30-min delay increased the odds of a higher 90-day mRS score by 6% (OR 1.062, 95% CI 1.001–1.125,
p
= 0.033). The post-bypass era, itself, however, was not associated with improved 90-day good outcomes (mRS 0–2: 40.2% vs. 44.6%; adjusted OR 0.98 [95% CI, 0.57–1.69];
p
= 0.93) or a shift in 90-day mRS disability (adjusted OR 0.93 [0.60–1.41];
p
= 0.72), though a nonsignificant trend toward improved 90-day excellent outcomes was observed (mRS 0–1: 23.5% vs. 34.5%; unadjusted OR 1.75 [1.01–2.90],
p
= 0.045; adjusted OR 1.51 [0.84–2.72],
p
= 0.17).
Conclusions
Implementation of a system-wide EMS LVO bypass protocol successfully reduced onset-to-door and onset-to-reperfusion times within a uniquely closed catchment geography. The impact on clinical outcomes, however, remains to be seen.