Background: The best strategy to identify patients with suspected acute ischemic stroke and unknown vessel status (large vessel occlusion) for direct transport to a comprehensive stroke center instead of a nearer primary stroke center is unknown.
Methods and Results: We used mathematical modeling to estimate the impact of 10 increasingly complex prehospital triage strategy paradigms on the reduction of population-wide stroke-related disability. The model was applied to suspected acute ischemic stroke patients in (1) abstract geographies, and (2) 3 real-world urban and rural geographies in Germany. Transport times were estimated based on stroke center location and road infrastructure; spatial distribution of emergency medical services calls was derived from census data with high spatial granularity. Parameter uncertainty was quantified in sensitivity analyses. The mothership strategy was associated with a statistically significant population-wide gain of 8 to 18 disability-adjusted life years in the 3 real-world geographies and in most simulated abstract geographies (net gain -4 to 66 disability-adjusted life years). Of the more complex paradigms, transportation of patients with clinically suspected large vessel occlusion based on a dichotomous large vessel occlusion detection scale to the nearest comprehensive stroke center yielded an additional clinical benefit of up to 12 disability-adjusted life years in some rural but not in urban geographies. Triage strategy paradigms based on probabilistic conditional modeling added an additional benefit of 0 to 4 disability-adjusted life years over less complex strategies if based on variable cutoff scores.
Conclusions: Variable stroke severity cutoff scores were associated with the highest reduction in stroke-related disability. The mothership strategy yielded better clinical outcome than the drip-'n'-ship strategy in most geographies.
