Background: Pre-hospital thrombolysis on Mobile Stroke Units (MSUs) have allowed dramatic rises in treatment within the ultra-early time windows, specifically the first hour after symptom onset (named the “Golden Hour”). Literature on the effect of this early treatment is still limited by the previous scarcity of cases.
Aims: We aimed to analyse the impact of time from onset to treatment on 90-day functional outcomes from pre-hospital thrombolysis cases aboard the Melbourne Mobile Stroke Unit with a focus on treatment in the first Golden Hour.
Methods: We included all patients receiving pre-hospital thrombolysis on the Melbourne MSU from 2017-2022 with completed 90-day follow-up. Distribution of modified Rankin score (mRS) grades were both analysed for trends across 30-min time epochs from onset and dichotomised for ≤60 and >60-min windows. Trends were analysed using a generalized pairwise comparisons model with adjustment for confounders.
Results: A total of 200 patients with completed 90-day follow-up were included, of which 37 (18.5%) received thrombolysis ≤60min. Baseline age, severity and need for thrombectomy were similar across time epochs. Treatment in the Golden Hour was associated with a substantial increase in good outcomes: mRS 0/1/baseline (aOR 2.74 [95%CI 1.29-6.13], p=0.01), mRS 0/2/baseline (aOR 3.10 [95% CI 1.36-7.84], p=0.01) and a trend towards mRS improvement by ordinal analysis (aOR 1.75 [95%CI 0.80-3.86], p=0.16), compared to all other time epochs. Every 30min delay of treatment was associated with progressive deterioration of 90-day outcomes: ordinal analysis (aOR 0.76 [95%CI .49-1.17], p=0.21) and mRS 0/1/baseline (aOR 0.84 [95%CI 0.71-0.98], p=0.029).
Conclusion: Pre-hospital thrombolysis in the Golden Hour is associated with dramatic improvements in 90-day functional outcomes compared to later timepoints. The ability of MSUs to substantially increase treatment in the ultra-early time window is likely one of the key drivers for published benefit.