Ischemic stroke patients non-LVO (large vessel occlusion) patients would require rapid IV thrombolysis in the nearest center. Whereas patients having LVO benefit from direct transportation for endovascular treatment in an intervention center. This study aimed to evaluate the prehospital triage strategies for suspected stroke patients in the U.S. A decision tree model and geographic information system were used to estimate the outcome of suspected stroke patients transported by ambulance within 4.5 hours after the onset of symptoms.

Nationwide implementation of the American Heart Association algorithm increased the number of good outcomes by +1.0% than transportation to the nearest center. The modified algorithms yielded an increase of +1.8% to +2.4% good outcomes, with an NNTI varying between 28 to 32. The algorithm devoid of a time limit was favoured in most states, followed by the algorithm with a less than 60 minutes delay. Tailoring policies at the county-level slightly reduced the total number of transportations to the intervention center (NNTI 31).

In conclusion, prehospital triage strategies can significantly improve the U.S. ischemic stroke population’s outcomes but increase the number of non-LVO stroke patients transported to an intervention center. The AHA triage algorithm followed currently is imperfect and should be modified, in order to allow more delay while transporting suspected LVO patients.