James Grotta, MD Director of Stroke Research Clinical Institute for Research and Innovation Memorial Hermann - Texas Medical Center Director, Mobile Stroke Unit Consortium University of Texas Health

Mobile Stroke Units Result in Better Outcomes and Can be Cost Effective

MedicalResearch.com Interview with:

Dr. Grotta

James Grotta, MD
Director of Stroke Research
Clinical Institute for Research and Innovation
Memorial Hermann – Texas Medical Center
Director, Mobile Stroke Unit Consortium
University of Texas Health 

MedicalResearch.com: What is the background for this study?

Response: We have good stroke treatments (thrombolysis and thrombectomy).  Since the initial studies showing benefit of thrombolysis, it has been difficult to improve on the amount of benefit except by speeding its delivery; the earlier the treatment, the better the outcome. Biologically, treatment in the first hour is likely to have greatest benefit since the brain is less irreversibly damaged and the clot is more soluble.

But treatment in the first hour is rare if it is carried out in the emergency department.  So MSUs take the emergency department to the patient. We know that Mobile Stroke Units (MSUs) can speed treatment; our study addressed if this be accomplished in the US, and how much difference does it make in outcome.  In particular, outcomes important to patients given the probable costs of implementing MSUs. 

MedicalResearch.com: What are the main findings? How practical are MSUs for hospital systems or cities to implement? 

Response: We were very successful in speeding treatment with the main impact in getting more patients treated in the first hour after symptom onset (33% MSU vs 3% with standard management).  This was achieved in US cities where the standard management was very good—better times than national benchmarks, and was even achieved during COVID.  More patients who should have been treated did in fact get treated on the MSU (97% vs 80% with standard management). This faster and more frequent (and also appropriate) treatment was translated into better clinical outcome—10-11% absolute increase in percent of patients completely recovering from their stroke, and 27% having better outcomes. Benefit was driven by those treated in the first hour, approximately 70% of whom recover back to their baseline.

Formal cost benefit analysis is on-going but consider this: Current direct cost of stroke in the US is about $200K/pt.  Let’s say a patient recovering to a mRS of 0-1 saves half of that by shorter length of stay, and less rehab.  Do the math….if a Mobile Stroke Unit treats 100 patients, and 10% more achieve a mRS of 0,1, the MSU saves $1M for every 100 patients treated.  A MSU costs $1M to build and $.5M to operate each year.  So it likely is cost effective if it treats 100 patients.  In Houston, we treat about 250 per year.

Response: Mobile Stroke Units result in better stroke outcomes and can be implemented in US cities.  

MedicalResearch.com: What should readers take away from your report?

Response:  MSUs result in better stroke outcomes and can be implemented in US cities.  

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

1. Whether and how Mobile Stroke Units should be more widely implemented is the next question.  This will depend on the results of the ongoing cost-benefit analysis that should be completed by the end of this year.  Assuming cost-effectiveness, implementation will depend on collaborative planning among EMS agencies and stroke centers in each community, and appropriate reimbursement for MSU services by CMS and other payers. If this occurs, I can see MSUs in all population centers of 500,000 or more and having a real public health impact on stroke outcomes. There’s lots of opportunity for geospatial and other modeling—e.g. implementation research.

2. We did not speed EVT. I think this would occur if we could identify LVO while on the MSU and then go straight to angio.  We can do this by doing CTA on the MSU, but research into new devices or biomarkers to immediately identify a patient with an LVO is another area of investigation.

3. Finally, patients/families still delay calling 911 thereby losing the opportunity for MSU benefit.  We need research on the impediments to calling 911 and how to make our 911 responses more nimble and accurate.

 No disclosures.  Funded by PCORI and consulting for Frazer Ltd.


Prospective, Multicenter, Controlled Trial of Mobile Stroke Units
James C. Grotta, M.D. et al
September 9, 2021
N Engl J Med 2021; 385:971-981
DOI: 10.1056/NEJMoa2103879



The information on MedicalResearch.com is provided for educational purposes only, and is in no way intended to diagnose, cure, or treat any medical or other condition. Always seek the advice of your physician or other qualified health and ask your doctor any questions you may have regarding a medical condition. In addition to all other limitations and disclaimers in this agreement, service provider and its third party providers disclaim any liability or loss in connection with the content provided on this website.


Last Updated on September 8, 2021 by Marie Benz MD FAAD