Gaps in stroke transfer system reduces survivors' chances of receiving critical treatment

Gaps in the U.S. stroke transfer system are drastically reducing survivors' chances of receiving critical treatment and increasing the likelihood that they will leave the hospital with a disability, according to a new study published in The Lancet Neurology.

Around one-third of ischemic stroke patients are eligible for endovascular thrombectomy, an effective intervention that changed the landscape of stroke treatment more than a decade ago.

More than 40% of people who receive endovascular therapy initially arrive at hospitals that don't offer the treatment. These patients require transfer to more advanced facilities capable of delivering thrombectomy. Previous analyses showed that the vast majority of stroke patients face hours of wait time between initial arrival and departure for transfer, known as door-in-door-out (DIDO) time.

The latest research led by investigators from the University of Chicago Medicine and University of Michigan confirms that these prolonged DIDO times reduce stroke survivors' chance of receiving endovascular therapy and increase their chance of leaving the hospital with significant disability.

These findings confirmed our logical hypothesis that delays in transferring patients to comprehensive stroke centers lead to worse outcomes."

Shyam Prabhakaran, MD, MS, senior author, the James Nelson and Anna Louise Raymond Professor and Chair, Department of Neurology, UChicago Medicine

"It's a wake-up call that should prompt everyone to strive for much shorter transfer times," he added. "No matter how we divided or analyzed the data, it showed that every minute of time saved has the potential to improve patients' functional outcomes."

Systemic issues in the stroke transfer system

In the study of over 20,000 patients with acute ischemic stroke, researchers found that just 26% of transfers occurred within 90 minutes, the maximum time recommended by the American Heart Association.

The likelihood of a patient receiving endovascular therapy declined steeply as transfer time delays grew. Patients with transfer times between 91 minutes and three hours had 29% less chance of receiving a thrombectomy. That number climbed to 65% when the DIDO time was longer than 4.5 hours.

"We have made tremendous progress in getting people timely acute stroke treatment after they arrive at the emergency department, which we call door-to-needle time, but the next frontier of acute stroke systems of care is improving inter-hospital transfer times for patients eligible for endovascular thrombectomy," Prabhakaran said.

"Every minute that passes before treatment increases the risk of losing neurologic functioning, and our results highlight missed opportunities for many stroke patients who are not initially seen at thrombectomy-capable centers."

Stroke patients with longer DIDO times had higher scores on the modified Rankin scale, a measure of overall disability used in clinical research.

They also had more complications after treatment and a lower likelihood of being able to walk independently after leaving the hospital.

Improving the system

The team's findings on the systemic delays in hospital transfer, which relied on data from the AHA's Get With the Guidelines-Stroke registry, reinforces their work from 2023. According to the registry's earlier data from more than 1,900 hospitals, the median door-in-door-out time for stroke patients was nearly three hours.

This new national study, however, is the largest examination of the relationship between those delays, missed opportunities for endovascular therapy and worse functional outcomes in acute ischemic stroke patients.

Systemic changes are especially important for areas with larger rural populations and those lacking formal stroke systems of care.

"With this study, we now have compelling evidence that we need to be paying greater attention to developing efficiencies within regional stroke systems of care with a targeted focus on minimizing door-in-door-out times," said Brian Stamm, MD, MSc, co-first author and clinical assistant professor of neurology at University of Michigan Medical School.

"We have seen successful global quality improvement initiatives reduce door-to-needle times for clot-busting medications. We should use those as a roadmap to do the same for reducing door-in-door-out time for inter-hospital stroke transfers."

An ongoing clinical trial sponsored by the National Institutes of Health and led by Prabhakaran, called Hospital Implementation of a Stroke Protocol for Emergency Evaluation and Disposition (HI-SPEED), is testing whether an intervention to reduce door-in-door-out times at eight large health systems around the U.S. will improve functional outcomes for acute ischemic stroke patients undergoing thrombectomy.

The researchers also note the need for ongoing research aimed at the window of time before a patient is brought to the hospital.

"Having prehospital tools that effectively identify patients who are more likely to receive endovascular therapy and triage them to thrombectomy-capable centers that provide that care is another way besides door-in-door-out interventions that we can increase access to this highly effective procedure," said Regina Royan, MD, MPH, co-first author and assistant professor of emergency medicine and neurology at University of Michigan Medical School.