Abstract Number ‐ 277: Mobile Stroke Unit Direct to Angiosuite Process Metrics and Clinical Outcomes
Authors: Tariq Muhammad Bilal , Jacob Asha P , Wang Mengxi , Yamal Jose‐Miguel , Nour May , Alexandrov Anne W , Alexandrov Andrei V , Navi Babak , Spokoyny Ilana , Jones William , Parker Stephanie , Rajan Suja S , Bowry Ritvij , Grotta James C , Czap Alexandra L 
Published: April 2023

Introduction
Mobile Stroke Units (MSUs) speed treatment with tPA, but did not affect time from alert to puncture time for endovascular therapy (EVT) in the Benefits of Stroke Treatment Using a Mobile Stroke Unit (BEST‐MSU), a prospective multicenter controlled trial comparing MSU with standard EMS management. The lack of improvement in EVT treatment time could be because the CTA to identify large vessel occlusions (LVOs), and alerting of the EVT team, were delayed in most MSU patients until after Emergency Department (ED) arrival. The impact of identifying LVOs by imaging on the MSU enabling a direct (from MSU) to angiosuite (DTAS) protocol has yet to be studied.

Methods
We conducted a pre‐specified substudy of tPA‐eligible stroke patients with LVOs on computed tomography (CT) and/or CT angiography (CTA) who were enrolled into the MSU arm of the BEST‐MSU study. We compared alert to puncture time and other process metrics, mean utility‐weighted modified Rankin Scale (uw‐mRS) and functional independence (mRS 0–2) at 90 days, and rate of early neurologic recovery (30% improvement in NIHSS score) at 24 hours in patients who were managed by DTAS vs post‐ED arrival diagnosis and alerting.

Results
A total of 169 MSU patients with LVOs were identified; 22 in the DTAS group and 111 in the non DTAS group. Data were not available for 36 LVO patients. Baseline characteristics including age, sex, ethnicity, prestroke mRS, and initial NIHSS were comparable between the groups. 100.0% of patients in the DTAS group vs 90.1% in the non DTAS received tPA (p = 0.264). EVT was performed on 85.0% of patients in the DTAS group vs 77.1% in the non DTAS group (p = 0.634). DTAS group had a faster alert to puncture time (108.00 min [94.75,124.75.] vs 150.50 min [121.25, 179.00], p< 0.001) and door to puncture time (37.00 min [25.50,62.75 vs 86.50 min [62.50,116.00], p< 0.001). The mean score on the uw‐mRS at 90 days was 0.626 ±0.367 in the DTAS group and 0.660 ±0.382 in the non DTAS group and after adjustment for age, baseline NIHSS, premorbid functional status, prior stroke/TIA and site, no significant difference was observed; (p = 0.54). In an unadjusted analysis, early neurologic recovery (72.7% vs 67.6%, (OR = 0.634, 95% CI [0.46,3.82]) and functional independence (50.0% vs 51.4%, p = 1.000) were comparable between DTAS and non DTAS patients. Patients in the DTAS group were less likely to receive general anesthesia (36.4% vs 71.2%, p = 0.004). Rates of recanalization (77.3% vs73,4%, p = 0.947) and post procedural PH‐2 hemorrhage (4.5% vs 0.9%, p = 0.746) were similar in the DTAS and non DTAS group respectively.

Conclusions
In tPA‐eligible LVO stroke patients, DTAS management resulted in shorter alert to puncture (42 minutes) and door to puncture times (50 minutes) with similar safety and clinical outcomes compared with non DTAS management. MSU DTAS represents an optimized pathway for LVO patients triaged and treated in the field.