Expert Conversations: Advances of the Mobile Stroke Unit

In part two of this series, Section Editor Amrou Sarraj, MD, discusses the clinical implications, advances, and future possibilities for the Mobile Stroke Unit with international experts as well as Geoffrey Donnan AO, and Stephen Davis AM, Professors of Neurology and Translational Neuroscience at the University of Melbourne and Co-Chairs of the Australian Stroke Alliance as well as James Grotta, MD, Director of Stroke Research, Clinical Institute for Research and Innovation, Memorial Hermann Hospital– TMC; Director, Mobile Stroke Unit Consortium. 

Listen to part one. 

Read the Transcript:

Dr. Sarraj:  Now the clinical implications.

People who listen to this will not see the background of Dr. Davis and Dr. Donnan, which is rural Australia with humongous areas of deserts, and everybody would be curious to hear how the mobile stroke unit concept work there, about the advances you'll have not only on the ground but up in the air. If you can share with us how much is done and what is the plan for the future.

Dr. Davis:  In Australia, a third of our population lives in rural and remote regions, and basically, they can't access the modern advances in stroke care, CT and let alone thrombectomy. So, there’s a massive geographic challenge, and if you're in a metropolitan city with a mobile stroke unit, there's only one currently in Australia, but others are on the drawing boards.

That one's in Melbourne. Basically, you're denied modern stroke care, and we don't think it's practical to put the current mobile stroke unit model in rural and remote areas because the current scanner, which is relatively lightweight, is still over half a ton.

Our concept is to develop ultra-lightweight brain imaging, and we're working with a company developing lightweight CT. Another company using electromagnetic technology to lower the weight from over 500 kilograms to under 100 kilograms and put these units into standard ride ambulances, but for a country like Australia, into aircrafts, helicopters, fixed wing including jets to cover the vast distances and then link it all up with a national tele stroke network.

That's a bold concept that Geoff and I have been funded to develop in partnership with these companies and there's interest in these lightweight technologies also in other parts of the world.

Dr. Sarraj:  It's definitely bold, but it's very innovative. To cover all of these areas, we have to come up with something new. We look forward to how this develops. What is the timeline?

Dr. Davis:  This is a five-year grant that we have, which is from our medical research future fund, which a bit like NIH, if you like or MRC. It's $40 million over 5 years. At the end of the five years, we should be able to at least know whether we've got a go or not.

I think that likelihood that we do is very, very high. I think the importance is that it could be a template for care in many other parts of the world. We were discussing offline earlier the other countries with geographical challenges similar to ours. You think of Canada, you think of China, Russia. The US has got large open spaces as well. I think the applicability will be well beyond our own shores.

Dr. Grotta:  As you know, Amrou, 80 percent of the US population lives within an hour of a comprehensive stroke center. While it's very important to show efficacy and to be able to help folks in the rural areas, I think we should keep our eye on the ball, at least in the United States where we know where we can apply these.

Eventually, if you have a technique that works, and you have comprehensive stroke centers, comprehensive stroke centers should have mobile stroke units. That's when you talked earlier about the guidelines, if you're going to have a comprehensive stroke center network, at some point written into the guidelines in the United States should be these type of mobile stroke units.

Dr. Donnan:  You were saying earlier, Jim, it's going to be hard for cities around the world not to adopt the mobile stroke unit model because it's very tough for medical organizers to go against current guidelines and, for example, in Australia -- I'd be interested to know what's happening in the US.

In Australia, we've got plans to get our second mobile stroke unit in Melbourne, and I know they've got three or four in Berlin already. We got approval for one in Sydney.

Steve and I are working on the possibility of getting mobile stroke units in almost every city in Australia. It's almost inevitable, as Jim was saying, that this is going to occur. I would be interested to know in the US how quickly that's going to happen.

Dr. Grotta:  Well, it's going to be driven by the dollar, by the economics, eventually. That's the burden we have to get over. It will happen. As we accumulate the data showing that we result in better outcomes that saves money to the healthcare system. Theoretically, mobile stroke units will get reimbursed.

But, right now, there is no reimbursement pathway even for giving TPA. We can't bill for the TPA we give on the mobile stroke unit, or if we give Tenecteplase. No matter what drug we give, there is no pathway for that. We have to achieve that. That's the next step to wide or widespread applicability.

Dr. Davis:  …funded by the state governments in Victoria. The actual units, I think as in Houston, Jim, were initially supported by philanthropic donation to get things up and running. We have a system where the government pays the ongoing paramedical nursing radiography costs. That's only going to be sustainable when cost-effectiveness is definitively shown.

We published that the Melbourne mobile stroke unit is cost-effective from colleagues we're working with. We're waiting particularly for the cost-effectiveness from BEST_MSU and B-proud to be released. We're very hopeful, Jim.

Dr. Sarraj:  All of those are great for patient's care. The translation of this, if I remember, summing up a few points. To get through the guidelines…a few years ago, looked at the number of patients treated within the golden hour. It was one percent of 60-plus thousand patients at the time.

The data from the mobile stroke units is consistent around one-third of the patients being treated within the golden hour, a significant increase in the number of patients treated. (Which) as we heard from you all, translated into improved clinical outcomes.

The improved clinical outcomes are because you're saving on the disability, on the poor outcomes, on the cost of the disability, and giving the patients quality life per years that they can use to go back and be productive to society, to their family. That is why it is cost-effective. It improves clinical outcomes, decreases times. It is cost-effective.

It is probably time for it to be integrated into the guidelines. Those challenges with a lack of reimbursement, hopefully, will dissolve. All these champions, like the great work that you all are doing, and then integrate it into being, as Dr. David said, covered by the healthcare system, not by philanthropy. Because philanthropy can go just so far, and grants.

Dr. Grotta:  Well, it seems logical, everything that you said, and it's true, it should. We live and breathe stroke every day. We go out and see these patients. It still is perceived as not the major public health problem in the world right now or even in the country, which is preoccupied with COVID and a lot of other issues.

Getting the attention of healthcare legislation and educators and policymakers is very difficult, even with good data. It's not easy. It's not a far gone conclusion that this is going to happen quickly. There is no established pathway for...

Remember, we're not a pharmaceutical company. We don't have a whole government affairs organization to go before a CMS, Medicare, or other organizations. We don't have a lobbying effort. This is all a grassroots operation growing out of the trial. We're open to any assistance of anybody listening to how we can achieve this.

Dr. Sarraj:  Paradoxically, Jim, it might be that the uptake in countries that have more government supported systems is quicker.

Dr. Grotta:  Absolutely.

Dr. Sarraj:  I'm thinking of the UK for example, and Canada, have very strong government-supported healthcare systems across the board. Getting back to my point earlier, it's very hard for bureaucrats to not go with current guidelines. It takes a pretty strong bureaucrat to ignore it.

So, within these systems which are much more state organized, there might be more rapid uptake of mobile stroke units than in perhaps countries like the US where it's more privately based.

Dr. Davis:  I think perceptions are changing, but we have to constantly say that while prevention is key with stroke, that stroke is the second cause of death around the world. In fact, Jim, as you know, in Asia, in China, for example. It's number one cause of stroke in Brazil and other countries.

It's a massive problem and a leading cause of disability. I think politicians are increasingly aware of stroke and its disastrous consequences and ability for treatments.

Just interested in one other concept we’re all focused on the golden hour, but Jim was one of the principal investigators of the original NINDS Trial, which showed that patients treated in the first 90 minutes, and this was a three-hour trial, did the best.

We call 90 minutes the silver hour. We're able to treat 50 percent of patients in the silver hour compared to about just over 10 percent of those in emergency departments. That's another target.

Dr. Sarraj:  Definitely. Hopefully, all of this great data, as mentioned, stroke is the number one cause of disability, chronic disability in the world. Hopefully, treating the patients earlier translates into reducing this disability. So, whatever investment being done on that front end will be saved on the other end.

Hopefully, if somebody listens, and really can help advocating and pushing for this for better patient care, this would be great.

Well, we have to take the other outcome. People will say, "Well, this is great. This can work in a city like Houston. It's a big city not centered like New York or Boston, where it's hard to drive to the patients," and all of that. That's one argument. How would you do it, logistically, deploy a mobile stroke unit in these areas?

The other one is when you have larger areas, not desert, but populated areas and I would poll my friend, Marc Ribo, he has a figure where he shows Catalonia, and he says, "We need 1,000-plus mobile stroke units to cover Catalonia. So, this is not logistically possible."

How do we answer that? How do we work around the crowded, centered cities, and the large areas of population where you need a number of those to cover?

Dr. Davis:  I think we need innovative solutions. I'm thinking not just New York or Boston. Even Jakarta, Shang Hi, cities where, Delhi, the traffic jams, Bangkok, are horrendous. I think the solution is to have more units, but that would only be feasible if we drastically reduce the cost.

That's why Geoff and I think that this innovative very lightweight imaging that could become virtually part of standard road ambulances is the way forward rather than the current MSU model.

Dr. Donnan:  For example, when we think lightweight with the electromagnetic device that we're working with this small company in Queensland, it's possible that weight might get down to 20 kilograms or even less. It's not impossible, if for example, New Delhi is a good example, of somewhere where you might need to get an imaging device through a very crowded metropolitan area. It might be on a motorbike.

Dr. Sarraj:  Is that right? Are we looking at these stroke units on a bicycle or motorcycle?

Dr. Donnan:  It may be. As Steve said, "We got to think outside the square here." We're not going to be able to have these mobile stroke units that we're working with today in every city around the world. We've got to take another leap forward to be able to bring this sort of acute care to seven billion people around the world.

Dr. Davis:  Might be drones delivering lightweight devices, and then multiple treatment teams within a city like Delhi and the nearest team goes. The drone delivers the imaging device, that gets the scans taken and treatment can follow. That's very future looking, but we do need to come up with new solutions.

Dr. Grotta:  I actually disagree with Marc Ribo. The area of Catalonia is not too much different from South East Texas in terms of geography. If you look, with Houston as the hub, what you have up to Montgomery County and down to Galveston and out west, and we could cover that area with four.

We would need more than one mobile stroke unit, of course, but if they're coordinated just like in our fire department, and one covers the other if they're busy, I think that you could cover very large areas. We cover a 13-mile radius with one mobile stroke unit that's a pretty big circle, a 13-mile radius. You have four of those, that's a pretty large geographic area.

Dr. Davis:  It’s about 20 kilometers, which is exactly our radius,

Dr. Davis:  It's not right that you need a 1,000 units. We got together on the statistics we have at hand at the moment. Berlin is a population of about 1.5 million. They have four units. We've got a population of nearly 5 million or about 5 million. We think we'll probably need three or four units.

Houston is about a million. Is that right, or more?

Dr. Grotta:  It's bigger.

Dr. Davis:  How many units do you think you'll need for your population, James?

Dr. Grotta:  Well, Houston, itself, we could use maybe three, but the metropolitan area, four would cover the metropolitan area. What I'm talking about, I'm not good at square miles but we're talking about a five million population.

Dr. Davis:  With the whole region?

Dr. Grotta:  Yeah.