Stroke Systems Science: Travel Delays and Access to Care

Advances in science cannot overcome traffic. Patients with strokes due to large vessel occlusions must be taken to hospitals that perform endovascular thrombectomy. Otherwise, these patients do not benefit from the latest and greatest in stroke neurology.

Investigators, including me, have taken interest in measuring the impact of travel delays on stroke care. With my co-investigators, a colleague and I performed a Monte Carlo simulation to model the effects of stroke transfer system configuration on endovascular therapy eligibility and expected outcomes.1 In a recent issue of Stroke, Dr. Regenhardt and colleagues present their analysis of a single hub and spoke system.2

They analyzed 234 patients who were transferred for endovascular therapy. Of these patients, who had a median ASPECTS score of 10 prior to transfer, only 27% of patients ultimately received endovascular therapy.  A median ASPECTS score of 10 correlates with very high eligibility for endovascular therapy prior to transfer.

They found, not surprisingly, that longer transfer time was associated with a decreased odds of undergoing endovascular therapy. The probability of getting endovascular therapy decreased by 1% for each additional minute of transfer time beyond 60 minutes. Being transferred at night was associated with slower transfers (despite less traffic!) and less endovascular therapy.

What does this mean? This means that a patient with a severe stroke who has the misfortune of being taken to a hospital that does not offer endovascular therapy has only a 27% probability of getting this therapy after transfer. At night time, it’s even worse.

Wonderful outcomes can be seen in clinical trials, but they do not benefit society if systems science does not keep up. Infrastructure upgrades and protocol developments may help, along with monitoring and benchmarking of transfer metrics.


  1. Parikh, Chatterjee, Diaz, et al. Modeling the Impact of Interhospital Transfer Network Design on Stroke Outcomes in a Large City. Stroke. 2018;49:370-376.
  2. Regenhardt, Mecca, Flavin, et al. Delays in Air or Ground Transfer of Patients for Endovascular Therapy. Stroke. 2018;49:1419-1425.

Neal Parikh Headshot

Neal S. Parikh, MD, earned his MD from Weill Cornell Medical College and completed residency training in neurology at the same institution. He is now an NIH T32 neuro-epidemiology and vascular neurology fellow at New York-Presbyterian Hospital/Columbia University Medical Center. He tweets @NealSParikhMD and contributes to Blogging Stroke as a blogger.

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