Outcomes of Patients Receiving Thrombolysis in a Mobile Stroke Unit: A 4-Year Retrospective, Observational, Single-Center Study.

Background And Purpose: Patients with acute ischemic stroke (AIS) eligible for thrombolysis benefit when thrombolysis is administered quickly, and mobile stroke units (MSU) can facilitate timely thrombolysis. We sought to compare time metrics and clinical outcomes of AIS patients receiving thrombolysis in an MSU compared with patients arriving via local emergency medical services (EMS).

Methods: We performed a retrospective, non-randomized, cohort study comparing MSU-arriving to EMS-arriving AIS patients from January 20, 2017 through November 30, 2020. The primary outcome was rate of return to baseline functional status as measured by the modified Rankin Score (mRS) 90 days after thrombolysis. Secondary outcomes included evaluation and treatment intervals from last known well, treatment rate in the first hour of symptoms, hospital length of stay, and mortality. Chi square and Student's t-test were used to compare groups.

Results: Of 1752 total patients with prehospital suspected stroke, 975 (55.7%) were transported via MSU, of whom 431 (44.2%) were diagnosed with stroke, including 368 (85.4%) with AIS, and 69 AIS patients (18.8%) received thrombolysis. Of 777 (44.3%) EMS-arriving patients, 373 (48%) were diagnosed with stroke, including 305 (81.8%) with AIS, and 74 (24.3%) received thrombolysis. Though not statistically significant, point estimates of the proportion of AIS patients treated with thrombolysis returning to baseline functional status were more commonly observed for MSU than for EMS transports when the baseline mRS was 0-2 (45.8% vs 33.3%), 0-3 (41.9% vs 33.3%), and 4-5 (71.4% vs 20.0%). MSU patients were more likely to receive thrombolysis in the first 60 minutes of symptom onset (31.9% vs 12.2%, p = 0.006). Overall mortality rates regardless of baseline mRS were similar between groups.

Conclusions: AIS patients received thrombolysis faster in the MSU compared with EMS and more frequently within 60 minutes of stroke onset. Point estimates for 90-day clinical outcomes of AIS patients treated with thrombolysis favored MSU without a statistically significant difference.