Stroke is the fourth leading cause of death in America, and a major cause of long-term disability.1 But a three-year study involving the nation’s first mobile stroke unit underway at the University of Texas Health Science Center in Houston could transform the way emergency service professionals deliver stroke treatment.
The majority of strokes, 87%, are ischemic and are caused by a blood clot in the brain. The gold standard and only FDA-approved treatment for the condition is tissue plasminogen activator (tPA).
When given intravenously within 3 hours (up to 4.5 hours in some patients), tPA may dissolve a blood clot before permanent neurologic damage occurs.2 Unfortunately, only about 5% of stroke patients are diagnosed in time to get this treatment.3
“Once ischemic stroke symptoms start, [patients] are losing about 2 million nerve cells each minute. Treatment with tPA is time dependent,” said Andrew Barreto, MD, study investigator and assistant professor of neurology at University of Texas Health Science Center (UTHealth).“We suspect that the most effective treatment is within the first hour, but we don’t know because it almost never happens.”
Improving “Door-to-Needle” Time for Stroke Treatment
To solve this problem and improve door-to-needle time, James C. Grotta, MD, the former chairman of neurology at UTHealth drew inspiration from a mobile stroke unit program being used in Germany and equipped an ambulance with a CT scanner and tPA.
The unit is staffed with a neurologist, CT technician, nurse, and paramedic.1 Before treating patients with tPA, a neurologist reviews the CT scan to diagnose ischemic stroke.1,2
“We have taken everything we need out of the ER, and we are bringing it to the door of the stroke victim,” said Stephanie Parker, RN, BSN, project manager for the UTHealth mobile stroke unit program. “If we can prove that cutting door-to-needle time improves outcomes and saves money over the long run, insurance providers will take notice.”
In previous efforts to improve door-to-needle time, the American Stroke Association has helmed numerous public health campaigns to help patients recognize stroke symptoms, and call 911. Emergency services have also tried many ways to streamline stroke diagnosis and treatment, including formation of designated stroke centers with 24/7 stroke teams, the placement of CT scanners in EDs, and recognition that dedicated neurological ED pathways can speed treatment.
But nothing during the past 20 years has significantly improved average treatment time. “We seem to have exhausted all the other efforts to get door-to-needle time under one hour,” Barreto said.
Evolution of the UTHealth Mobile Stroke Unit
The UTHealth Development Board approved Grotta’s plan for a mobile stroke unit study, and three Houston area hospitals – Memorial Hermann, Houston Methodist, and St. Luke’s Medical Center – have agreed to participate.1 The program is now moving forward and seeking additional funding from the National Institutes of Health (NIH).
“Every dime we have used to get the project up and running has come from donations. Right now we only have one ambulance, but if we can get more funding we may try to expand,” Parker said.
“There have been lots of regulations and red tape to work through,” Barreto added. “Since this is a study, we can’t charge for the tPA, and one bottle costs almost $8,000. We have gone out on a lot of false alarms, because there are lots of conditions that mimic stroke.”
He estimated UTHealth has treated about 20 patients with mobile stroke units since the study began in spring of 2014.
The main objective is to find out whether giving tPA within the first hour of stroke onset will improve outcomes. To achieve this goal, the stroke unit goes out for seven days and then takes seven days off, during which regular ambulances serve as the control group.
When the mobile stroke unit picks up a patient having a stroke, both the doctor on board and a telemedicine neurologist review the patient’s symptoms and the CT scan. Both neurologists then independently decide if tPA is necessary, but the decision is blinded.
“We hope to show that the decision to treat will be in enough agreement that the on-board neurologist can eventually be replaced by the telemedicine neurologist,” Barreto said. The team hopes this will reduce cost and increase feasibility for broader program implementation.
“If we can get about 300 patients into our study, I think there will be more than enough data to show improved outcomes, less years of disability, and cost effectiveness,” said Barreto said.
“The early results have been encouraging. About 30% of our patients have door-to-needle times less than 60 minutes, compared with the control patients who are being treated about 45 to 50 minutes later. We have had quite a few patients walk out of the hospital within 10 days, free of any disability,” Parker said.
The results are not yet available to the public, but Barreto has been impressed by his personal experience.
“I was out on a call where we were able to start treatment in the ambulance in under 50 minutes. The patient had developed blindness and complete one-sided paralysis. I watched these symptoms resolve before my eyes. A few days later the patient walked out of the hospital,” Barreto said.
Since the UTHealth program started, the Cleveland Clinic in Ohio has also started a mobile stroke unit, but that unit is not part of the current study. Preliminary data from the UTHealth mobile stroke unit trial will be presented at the 2015 International Stroke Conference this February in Nashville.
Chris Iliades, MD is a full-time freelance medical writer based in Cap Cod, Massachusetts.
This article was medically reviewed by Pat F. Bass III, MD, MS, MPH
- University of Texas Health Center at Houston. “UTHealth introduces the nation’s first Mobile Stroke Unit.” 3 Feb 2014. Available at: https://www.uth.edu/media/story.htm?id=b1485cfc-110f-4a4c-91ea-06b573b3ba6d.
- American Stroke Association. “Stroke Treatments.” 23 May 2013. Available at: http://www.strokeassociation.org/STROKEORG/AboutStroke/Treatment/Stroke-Treatments_UCM_310892_Article.jsp.
- Grotta JC et al. “tPA for Stroke: Important Progress in Achieving Faster Treatment.” JAMA. 2014; 311(16):1615-1617.