Mobile Stroke Unit CTA and Direct Notification of Interventional Team Shortens Door-to-Puncture Time by One Hour

Introduction: Endovascular thrombectomy (ET) is an effective but time sensitive treatment of acute ischemic stroke. Time from Emergency Department (ED) arrival to start of ET (door-to-puncture time, DTPT) is a modifiable metric. One of the most time consuming steps in prolonging DTPT is identification of large vessel occlusion (LVO) by CT angiography (CTA). BEST-MSU is a prospective multicenter comparative effectiveness study of tPA-eligible patients managed on a mobile stroke unit (MSU) vs Emergency Medical Services (Standard Management, SM). After discovering that DTPT was greater than 60 minutes in both groups at three BEST-MSU centers in 2018, we began to routinely obtain CTA on the MSU and directly alert the ET team at receiving hospitals if a LVO was identified. We hypothesized this would shorten DTPT by over 30 minutes. Methods: In this single center experience, we compared the median (interquartile range, IQR) DTPT and MSU on-scene time for MSU patients having on-board CTA and then ET from 9/2018 to 7/2019 to corresponding MSU ET patients (excluding any that had on-board CTA) from 8/2014 to 8/2018. All CTAs were completed after tPA bolus and during tPA infusion on a Ceretom 8 slice scanner with OptiStat hand injector. All imaging occurred on-scene with the MSU stationary. Consent was obtained for all patients and strict radiation safety guidelines followed. Results: 13 consecutive patients having CTA on-board the MSU and then ET were compared to 84 patients in the pre-on-board CTA group. Baseline characteristics including median NIHSS score (20 in both groups) and frequency of tPA (85% on-board CTA vs 89% pre-on-board CTA) were comparable. Median DTPT was 60 minutes shorter with on-board CTA and direct notification of the interventional team from the MSU; 34 minutes (IQR 30-57) vs 94.5 minutes (IQR 69.75-117.25) (p < 0.001). Despite the additional time to obtain the CTA on the MSU, on-scene time was only slightly prolonged and did not offset the reduction in DTPT (on-board CTA 30 minutes (IQR 28-33) vs pre-on-board CTA 27 minutes (IQR 23-31) (p = 0.01). Conclusion: Pre-hospital identification and notification of LVO by a MSU allows a one hour reduction of DTPT, and can be utilized to establish a direct to angiosuite protocol.