New study shows mobile stroke units lead to better patient outcomes

Specialized ambulances allow for rapid diagnosis and treatment of stroke.

Every 40 seconds, someone in the United States has a stroke — a change in normal blood flow in the brain. And in every case, quick treatment is crucial.

A study published Sept. 9 in the New England Journal of Medicine finds that mobile stroke units — specialized ambulances that allow for expedited imaging diagnosis and treatment of patients experiencing stroke, before arriving at a hospital — lead to better outcomes for patients, both immediately and three months later.

BEST-MSU is a multi-year, multi-site study conducted in Los Angeles and six other U.S. cities. It compared outcomes of patients treated in mobile stroke units with those treated in the hospital after traditional emergency response and transport.

“The results of this landmark trial in prehospital medicine show that for ischemic stroke, for patients treated earlier in mobile stroke units, as compared to later in the emergency department, there is significant clinical improvement,” says May Nour, MD, PhD, interventional neurologist, director of UCLA Health’s Mobile Stroke Unit and co-author of the study.

“Out of 100 patients treated in a mobile stroke unit with clot-busting medications rather than later in the emergency department, 27 will have less final disability, 11 of whom will become disability free,” she says.

Working like a primary stroke center emergency department on wheels, mobile stroke units are equipped with a CT scanner, laboratory equipment and trained clinical staff. This highly specialized team, along with the resources on the unit, can efficiently diagnose stroke and begin administering brain- and life-saving therapies earlier than ever before.

“Mobile stroke units bring the hospital to the patient in this time-sensitive emergency,” Dr. Nour says. “Our team provides clinical assessment, imaging diagnosis, hyperacute treatment and routing to the most appropriate level of stroke care in accordance with L.A. County EMS guidelines.”

Stroke affects more than 800,000 Americans each year. Most of these strokes, 80%, are ischemic, resulting from a lack of blood flow to brain tissue. The other 20% are hemorrhagic, meaning there’s bleeding in the tissue of the brain. Stroke is a major cause of disability and death in the United States.

Stroke risk can be lowered through lifestyle changes and targeted preventative therapies, Dr. Nour says. High cholesterol, high blood pressure, diabetes and smoking increase stroke risk. But the disease can also be caused by irregular heart rhythms, particularly atrial fibrillation, and increased blood clotting, such as in COVID-19-related ischemic stroke, she says.

Mobile stroke units are dispatched alongside primary 911-responding ambulances and fire engines with paramedics in Los Angeles County, Dr. Nour says. Together, these emergency responders evaluate patients to determine their eligibility for assessment and treatment in the mobile stroke unit and admit them if stroke symptoms are within 24 hours from onset.

Dr. May Nour

The county’s program is funded by philanthropic donations led by the Arline & Henry Gluck Foundation and support from the Los Angeles County Board of Supervisors.

Studies are underway to assess how in-the-field treatment by mobile stroke units may offset future health care costs, Dr. Nour says.

“If we can save patients from living a life with disability and avoid their dependency on long-term health care facilities, this is anticipated to translate into cost savings for the health care system, in addition to allowing patients to reintegrate into the workforce,” she says.

Dr. Nour says she expects health care utilization results from the BEST-MSU (Benefits of Stroke Treatment Delivered by a Mobile Stroke Unit) study in early 2022.

Meanwhile, the latest study provides ample evidence supporting what Dr. Nour calls “a big change in the infrastructure of emergency medical care.”

“I think the future for stroke care and other time-sensitive emergencies is, rather than wait for the patient in the hospital, bringing the hospital to the patient for the initiation of hyperacute, lifesaving treatments,” Dr. Nour says. “I think this is going to change the fabric and landscape of EMS care, and it’s really exciting to be part of this big paradigm shift. As the first mobile stroke unit to launch in the Western third of the United States, first in California and one of seven U.S. cities participating in the BEST-MSU study, we are very proud to have been part of this tremendous advancement in prehospital care.”

Learn more about the UCLA Arline and Henry Gluck Stroke Rescue Program.