Mobile stroke units becoming more common despite cost effectiveness questions
EXPERT ANALYSIS FROM THE INTERNATIONAL STROKE CONFERENCE
HOUSTON – Mobile stroke units – specially equipped ambulances that bring a diagnostic CT scanner and therapeutic thrombolysis directly to patients in the field – have begun to proliferate across the United States, although they remain investigational, with no clear proof of their incremental clinical value or cost effectiveness.
The first U.S. mobile stroke unit (MSU) launched in Houston in early 2014 (following the world’s first in Berlin, which began running in early 2011), and by early 2017, at least eight other U.S. MSUs were in operation, most of them put into service during the prior 15 months. U.S. MSU locations now include Cleveland; Denver; Memphis; New York; Toledo, Ohio; Trenton, N.J., and Northwestern Medicine and Rush University Medical Center in the western Chicago region. A tenth MSU is slated to start operation at the University of California, Los Angeles later this year.
Early data collected at some of these sites show that initiating care of an acute ischemic stroke patient in an MSU shaves precious minutes off the time it takes to start thrombolytic therapy with tissue plasminogen activator (tPA) compared with that at a hospital, and findings from preliminary analyses suggest better functional outcomes for patients treated this way. However, leaders in the nascent field readily admit that the data needed to clearly prove the benefit patients receive from operating MSUs are still a few years off. This uncertainty about the added benefit to patients from MSUs couples with one clear fact: MSUs are expensive to start up, with a price tag of roughly $1 million to get a MSU on the road for the first time, and also expensive to operate, with one estimate for the annual cost of keeping an MSU on the street at about $500,000 per year for staffing, supplies, and other expenses.
“Every U.S. MSU I know of started with philanthropic gifts, but you need a business model” to keep the program running long-term, James C. Grotta, MD, said during a session focused on MSUs at the International Stroke Conference sponsored by the American Heart Association. “You can’t sustain an MSU with philanthropy,” said Dr. Grotta, professor of neurology at the University of Texas Health Science Center in Houston, director and founder of the Houston MSU, and acknowledged godfather of all U.S. MSUs.
The concept behind MSUs is simple. Each one carries a CT scanner on board so that, once the vehicle’s staff identifies a patient with clinical signs of a significant–acute ischemic stroke in the field and confirms that the timing of the stroke onset suggests eligibility for tPA treatment, a CT scan can immediately be run on site to finalize tPA eligibility. The MSU staff can then begin infusing the drug in the ambulance as it speeds the patient to an appropriate hospital.
Another advantage to MSUs, in addition to quicker initiation of thrombolysis, is “getting patients to where they need to go faster and more directly,” said Dr. Nour.
“Instead of bringing patients first to a hospital that’s unable to do thrombectomy and where treatment gets slowed down, with an MSU you can give tPA on the street and go straight to a thrombectomy center,” agreed Jeffrey L. Saver, MD, professor of neurology and director of the stroke unit at UCLA. “The MSU offers the tantalizing possibility that you can give tPA with no time hit because you can give it on the way directly to a comprehensive stroke center,” Dr. Saver said during a session at the meeting.
