Stroke is one of the leading causes of death in the
United States, with over 795,000 cases yearly. In particular, ischemic
strokes have the highest prevalence, constituting 87% of all stroke
cases.1
Early administration of tissue plasminogen activator (tPA) has proven
to limit the risk for damage and functional impairment in patients with
acute ischemic stroke.2-4 However, one of the most
significant barriers to successful stroke management is administering
tPA within the recommended window of 3 hours.5
The first mobile stroke unit (MSU) in the US was implemented in 2015
and allowed for earlier tPA administration, leading to significant
improvements in functional outcomes for patients with stroke.
Recent pivotal studies, Berlin PRehospital Or Usual Delivery in Stroke Care (B_PROUD; ClinicalTrials.gov Identifier: NCT02869386)
and Benefits of Stroke Treatment Delivered by a Mobile Stroke Unit
Compared with Standard Management by Emergency Medical Services
(BEST-MSU; ClinicalTrials.gov Identifier: NCT02190500),
showed significant improvements in 90-day disability scores for
patients with acute stroke treated on an MSU compared with emergency
medical service (EMS) management in both Germany and the US. The B_PROUD
study also showed that the median time from dispatch to initiation of
thrombolysis for patients treated with an MSU was 20 minutes shorter
than with conventional ambulances. 6,7
Essentially everything you need to do for a stroke is in the MSU.
While early studies show promising results for patients treated with
MSUs, there are significant barriers to implementing and standardizing
these services in the US. Many MSUs have not fully integrated into the
existing EMS systems, making it difficult to streamline treatment
processes. Additionally, most MSUs operate in densely populated cities.
Research has suggested several methods for adapting these services to
nonurban settings, such as air ambulances and various transport
strategies, but further studies are necessary to prove these concepts.8,9
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clinical guidelines for standardized care. There is a call to action for
guideline committees, medical societies, and stroke leadership to
update the level of evidence of MSUs to reflect more recent efficacy
trials. Another step for MSU expansion is for regulatory bodies to
establish a process to accredit MSU programs using standardized quality
measures.8
Additionally, MSUs face issues receiving reimbursements from insurance.8
The lack of reimbursements for MSUs in the US increased reliance on
grants to support program costs and has limited the expansion of this
service across the nation.10 The body of data supporting MSU
cost-effectiveness is still in its early stages and additional data is
necessary to support the need for reimbursement. Recent data shows that
MSU cost-effectiveness is due to the reduction in long-term disability
costs and that MSUs yield a gain of 0.591 quality-adjusted life years
per dispatch.11
To discuss MSU implementation barriers, we spoke with James Grotta,
MD, founder of the first MSU in the US and the director of stroke
research at the Clinical Institute for Research and Innovation, Memorial
Hermann-Texas Medical Center in Houston. We also spoke with Matthew T.
Bender, MD, neurosurgeon and assistant professor in the division of
stroke and cerebrovascular disease at the University of Rochester
Medical Center in Rochester, New York, to gain insight on current
barriers for treating acute ischemic strokes.
How similar is treating someone in an MSU compared with the
emergency department? Is there something in the emergency department
that’s not in an MSU?
Dr Grotta: For strokes, the answer is no.
Everything that we need to treat a patient in the emergency room for a
stroke, we can do in the MSU. In a hospital, there are other things we
can do for patients with stroke — for example, a thrombectomy. Patients
move from the emergency room into an endovascular suite.
Essentially everything you need to do for a stroke is in the MSU. Now
there are a host of other emergency procedures in the emergency room
that could be done on an MSU.
Dr Bender: The MSU is essentially a stroke
emergency department on wheels. Providers have all the tools needed to
evaluate, stabilize, and treat a patient suffering a stroke. They have a
narrower focus than emergency department providers and can defer
non-neurologic diagnoses to the emergency room.
Could you elaborate on the gaps preventing timely administration and decision-making for tPA?
Dr Grotta: Most of the time, if the
physician is on board the MSU, the CT scan comes up on the computer and
you can see it right away. However, in some MSUs, often the physician is
present through telemedicine. In some systems, the CT scan must be
transmitted to a radiologist to be read. That might produce a few
minutes of delay.
I think that’s an unnecessary step because you just have to read the
CT to ensure there is no blood. That doesn’t usually require a
neuroradiologist to read it. You get a more skilled reading from a
neuroradiologist, but the neurologist can generally identify when
treatment is appropriate.
The biggest thing we have shown is that treatment in the first hour
after symptom onset is critically important. In that first hour, every
little thing that takes up a few extra seconds makes a difference.
Dr Bender: Stroke neurologists are making
this decision via telemedicine. They need to formulate their own
perspective based on the clinical scenario and imaging but then elicit
pre–existing goals of care and obtain consent from the patient or family.
It requires efficiency and parallel processing. As a result of our
study findings, the MSU team has reviewed additional parallel procedures
to facilitate faster treatment decision times.12
What is the most significant barrier to treatment for
patients with stroke and what do you propose to help address these
barriers?
Dr Grotta: The most significant barrier is
that patients do not call 911. If everybody called 911 when they had a
stroke, we would be treating many more patients right now.
Only 12% of patients with stroke get treated with tPA. Admittedly,
some cannot be treated with tPA because they have contraindications like
bleeding problems, the stroke is not severe enough, or some other
illness that precludes it.(So in treating 1000 stroke patients only 14.4 get fully recovered, 1000*12%*12%, THAT IS COMPLETELY APPALLING! What is your hospital doing to address that failure?)
If everybody called 911 when symptoms came on, we could quadruple the
number of patients currently being treated. Our treatment, tPA, is
pretty good(Your definition of good has no correlation to a survivor's definition of 100% recovery), so treating more patients with the existing treatment would
make the most significant difference.
We need to figure out how to alert patients that they are
experiencing a stroke and there is research on alerting devices that
people might wear.
Dr Bender: Early recognition of stroke symptoms and alerting emergency services remains the most significant barrier.
Through a partnership with the Cabrini Foundation,
we are working to increase awareness and recognition of stroke symptoms
in underserved communities within the Rochester metropolitan area.
There are currently no clinical guidelines on a national
level for MSUs. Based on your experience and research, what massive
overhauls and protocols are needed for MSUs? Who would be the
decision-makers for these guidelines?
Dr Grotta: In our health care system, it is
all about money. I do not mean to say that negatively, but things that
are reimbursed get done, and things that are not reimbursed do not get
done. In a sense, MSUs are an expensive operation for a hospital to
implement, but they are worth it because we have shown that they are
quite effective.
It requires an investment upfront, and right now, there is no
adequate reimbursement for MSUs because they are a new thing. Insurers
and Medicare do not recognize MSUs as a place of service.
The other impediment is that there are 20 or 30 MSUs right now, and
you have to take a year between the time you order an MSU before one
rolls out. There is no economy of scale because there is not a huge
demand.
If and when MSUs get reimbursement with Medicare, then we will be able to scale up our production capability.
Dr Bender: We are at a stage where the MSU
concept is spreading. To foster that growth, MSU-based stroke treatment
needs to be recognized by third-party payors and the Centers for
Medicare & Medicaid Services, which is reasonable given that
randomized prospective data shows MSU care expedites thrombolysis and
leads to better clinical outcomes for patients with stroke.
What additional data or research is needed to help inform future clinical guidelines?
Dr Grotta: One of the things we have yet to show about MSUs is how we can help patients with large vessel occlusion.
Right now, the main benefit of MSUs is to get tPA in faster. However,
some patients do not qualify for tPA or need treatment beyond tPA.
Those are the patients with large vessel strokes.
Thrombectomy is another treatment for patients who have the biggest strokes where tPA often does not work, and we pull the clot out with a catheter. However, there are only some hospitals that do that.
What MSUs can do is triage patients more effectively to these
thrombectomy centers and get thrombectomy done faster. Nevertheless,
that remains to be proven.
Most importantly, having an MSU be used for just one disease does not make logical sense. We must find other emergency conditions that MSUs can help with.
Editor’s Note: This interview was edited for clarity and length.
Nathaniel R. Ellens
Derrek Schartz
Redi Rahmani1, 
Sajal Medha K. Akkipeddi
Stephanie A. Parker
Thomas K. Mattingly
James C. Grotta