Abstract Body: Background—Intravenous thrombolysis（IVT）is an approved therapy for patients with acute ischemic stroke (AIS). In-hospital delay is one major concern prohibiting patients from receiving IVT. Emergency Stroke Unit (ESU), a new concept of stroke unit, was highly organized and managed in a centralized space at the Accident and Emergency Department and involved clinical evaluation, imaging assessment, and treatments. ESU was equipped with a 0.23-T mobile, low-field MR imaging (LF-MRI) scanner, enabling for distinguishment between acute phase cerebral hemorrhage and cerebral infarction (≤4.5 h) within 1 min and 17 seconds instead of routine CT, using the HEIR (Hematoma Enhanced Inversion Recovery) sequence we previously designed.
Methods
The Emergency Stroke Unit for Acute Cerebrovascular Events (ESU-ACE) study was a multicenter, week-wise randomized, controlled trial aiming to evaluate the safety and efficacy of the ESU workflow using LF-MRI in shortening the DNT and improving functional outcomes in AIS patients, as compared with standard IVT practice. After the two-week guided testing period, the centers that could not establish the ESU process were excluded from the study. Individuals recruited in the study were required to be eligible for IVT and could be treated within 4.5 hours after symptom onset. The primary efficacy outcome was DNT. The primary safety outcome was symptomatic intracranial hemorrhages and death within 36 hours after thrombolysis. The average DNT was approximately 50 minutes for the standard IVT procedure in China. We estimated that ESU would reduce DNT by 30 minutes. To determine the study sample size, we assumed the lower boundary of the 97.5% conference interval was 25 minutes to estimate the difference in the mean DNT between standard care and ESU. With a power of 90% and a one-sided α level of 0.025, the target sample size for each group was 55 patients.
Results—The ESU-ACE trial was initiated on August 8, 2024. We have screened 24 sites and included 10 eligible centers across China. Patient enrollment was completed on October 16, 2024. We expect to complete the 3-month follow-up by January 17, 2025.
Significance
Compared to the standard IVT workflow based on recent guidelines, we hypothesize that this novel ESU workflow will significantly shorten the DNT time and, therefore, may safely improve patients’ functional outcomes.