Abstract WP314: Baltimore City Acute Stroke EMS Routing Pilot Study

Abstract

Introduction: New EMS routing protocols are being proposed to divert acute stroke patients, based on the likelihood of having a large vessel occlusion (LVO), directly to Comprehensive Stroke Centers (CSC), in order to reduce the inherent delay of a secondary transfer from a Primary Stroke Center (PSC) to a CSC. Within Baltimore City, transfer from a PSC to a CSC for mechanical thrombectomy (MT) adds, on average, an additional 90-minute delay in achieving reperfusion. Aim: To determine the feasibility and safety of an EMS routing protocol in which, patients determined to have an LVO-related acute stroke, based on use of a stroke severity score in the field, are directed to the nearest CSC bypassing closer PSCs within Baltimore City. Methods: A prospective observational study was conducted over a six-month period, from September 2017 to March 2018. Acute stroke patients with a LAMS of ≥4 were taken by EMS to the nearest CSC, bypassing closer PSCs, as long as the travel time did not exceed an additional 30 minutes. Data collected at the three CSCs included transport times, IV-tPA and MT use in the diverted patients, time from onset to treatment and 90-day functional outcomes. Descriptive statistics were used to analyze the data. Results: Forty-five patients with LAMS of ≥4 were diverted to a CSC. Approximately 50% (20/45) had a final diagnosis of acute ischemic stroke and 35% of those were eligible for an intervention, either IV-tPA or MT or both. Average onset to IV-tPA bolus time was 114 minutes (93-163 minutes). Average onset to groin puncture was 197 minutes (192-202 minutes). There were 4 in-hospital deaths. Among survivors, the 90 day modified Rankin Scale (mRS) ranged from 0-3. Mean field transport time was 17 minutes (range: 4-63 minutes). None of the re-routed patients were ineligible for IV-tPA due to additional time to CSC. There were no reported adverse outcomes due to increased travel time associated with diversion. Conclusion: Implementation of EMS routing protocols to divert acute stroke patients suspected of having an LVO past PSCs to CSC within cities is feasible and appears safe. The limitations of this study include small size, short duration and small region of implementation. Further study is warranted on a larger scale both in population and geographic area.

The Maryland Acute Stroke Emergency Medical Services Routing Pilot: Expediting Access to Thrombectomy for Stroke

“…An observational restrospective study of prospective acquired data during the pilot revealed 45/203 (22%) of eligible patients were rerouted, and of those, 20/45 (44%) had ischemic stroke and half of these had an intervention (IVT, MT or both). There were also 10/45 (22%) patients with intracerebral hemorrhage (ICH) that bypassed PSCs, which typically are transferred from PSCs to CSCs ( 25 ).…”