Abstract Body: Background. The intervention of mobile stroke units (MSUs) on a patient experiencing an acute ischemic stroke significantly improves outcomes compared to standard of care provided by emergency medical services. It allows for more patients to be treated with intravenous thrombolysis during the Golden Hour after last known normal (LKN). While prompt thrombolysis treatment restores blood flow, its effect on the inflammatory cascade triggered by the stroke has not been examined.
Methods. Blood samples were obtained on the MSU through a prospective cohort study. NIH Stroke Scale (NIHSS) scores were recorded on the MSU and at the hospital discharge. Nine proinflammatory plasma cytokines were measured with the MesoScale Discovery S-Plex assay from plasma samples obtained on the MSU and 24 hours later.
Results. Seventy adults were analyzed, including 46 patients treated on the MSU between August 2021 and May 2024, and 24 controls. Twenty-six (56%) MSU patients were diagnosed with a confirmed acute ischemic stroke (AIS), 3 had an intracerebral hemorrhage and 17 (37%) were stroke mimics. Confirmed AIS patients had a median age of 65 (range 36-88) years, 58% were male, 73% white. Their initial median NIHSS score was 7 (range 1-22). Twenty-three (88%) received intravenous thrombolysis (tPA or TNK). Blood was obtained a median of 57 (range 26-355) minutes after LKN. We first compared AIS, stroke mimics and controls and found significant group differences for interleukins IL12p70, IL17, IL1β, IL2, IL4 and IL6. Pairwise differences indicated that IL12p70, IL17 and IL2 were significantly lower in AIS compared to stroke mimics. Among AIS patients, sixteen (61%) received treatment on the MSU within the Golden Hour. Patients treated during the Golden hour had median levels of IFNγ, IL17 and IL4 higher, while median levels of IL-12p70, IL-1β, IL-2, IL-6, TNFα and IL-10 levels were all lower, perhaps suggesting an effect of thrombolysis treatment timing. The NIHSS score changes between MSU and discharge were less favorable for patients treated after the Golden hour. Initial and 24-hr IL10 levels were positively correlated with time elapsed between LKN and MSU intervention.
Conclusions. Our study found that the proinflammatory cytokines IL12p70 and IL2 are significantly reduced while IL4 and IL6 are significantly elevated in AIS patients, compared to normal controls. We observed some trends suggesting that thrombolysis within the Golden Hour influences the inflammatory response.