Exploring Stroke Detection and Management with Interventional Neurologist Dr. Michael Waters

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G'Day did you realize that Hippocrates first described the sudden paralysis associated with stroke? And then in 2020, there was an estimated 39,000 stroke events in Australia, more than a hundred every day. With the incidence of stroke increasing from the age of 30 and their various causes of stroke varying, depending upon the age of the patient. Today, we're going to learn more about it. In the previous episode we spoke to Ewan(Puggy) and Liz about Puggy's stroke. And we heard about his intimate journey from their stroke to the a long road of recovery. Today we will dive into the diagnosis treatment and then the intricacies of cerebrovascular events to provide a comprehensive outline and treatment for these serious events.

Gavin NImon: 1:06

G'day and welcome to Aussie Med Ed, the Australian medical education podcast, designed with a pragmatic approach to medical conditions by interviewing specialists in the medical field. I'm Gavin Nimon an orthopaedic surgeon, and I'm based in Adelaide, and I'm broadcasting from Kaurna land I'd like to remind you that if you enjoy this podcast, please subscribe or leave a review or give us a thumbs up as I really appreciate the support and it helps the channel grow It's my pleasure now to introduce Dr. Michael Waters, an interventional neurologist who works at the Royal Adelaide Hospital following neurology training, he undertook a further three fellowship years, in interventional neuroradiology, both in Australia and in the United States. He works as a stroke neurologist and neurointerventionist, providing minimally invasive endovascular treatment for stroke, cerebral aneurysms and other neurovascular diseases. Welcome Michael!

Dr Gavin Nimon: 1:52

Michael, thank you very much for coming on Aussie Med Ed.

Dr Michael Waters: 1:55

No worries, good to be here.

Dr Gavin Nimon: 1:57

I'd like to, first of all, you've heard the story of Puggy, a friend of mine and his stroke. How would you actually define a stroke and how common are they that occur in Australia and around the world?

Dr Michael Waters: 2:07

Yeah, so I guess traditionally strokes were called cerebrovascular accidents or CVA's. And that naming changed in recent times because I guess we realized that they weren't really accidents anymore. We usually had a clear cause for them. And so now they're just termed generally a stroke and that covers both ischemic and hemorrhagic. So basically a stroke is damage to the brain due to a problem with the blood vessels. And the problem with the blood vessels can be a blocked blood vessel, which would be an ischemic stroke or a burst blood vessel, which is a hemorrhagic stroke, bleeding of the blood vessels. So that's the general classification. They're quite common. In Australia about 5%. The prevalence of stroke is about 5 percent in the over 65 age group. As you get to over 85, the prevalence is about 15%. So that's quite common. And in Australia, about 85 % of those strokes are ischaemic. And about 15% of hemorrhagic and that, changes as you go around the world and even within Australia. So Indigenous and First Nations people in Australia have a much higher incidence of stroke and prevalence of stroke, and especially hemorrhagic stroke. They're o overrepresented in that category. And then in certain parts around the world, the incidents and prevalence will be different as well. For example, subarachnoid hemorrhage, a type of hemorrhagic stroke. It's much more common in Japanese and Finnish people. Hemorrhagic stroke is more common in certain ethnic groups, including Chinese. And then also different types of ischemic strokes are more prevalent in different populations as well. For example, intracranial atherosclerosis as the cause of a stroke is quite common as a stroke subtype in the Chinese especially Han Chinese population. So it does vary as you go around the globe globally, about two thirds of stroke ischemic and about one-third is hemorrhagic which is slightly different from the numbers in Australia where the even higher proportion are ischemic.

Dr Gavin Nimon: 4:06

Okay, and where does transient ischemic attacks or TIAs fit into this picture? Are they mini strokes that just don't give a significant effect or are they just minor small blips in the actual function of the brain for short term function.

Dr Michael Waters: 4:19

Yeah, a mini stroke is a reasonable way to classify them, but they're really different by definition and by time course only. So a TIA by its definition is transient ischemia, which lasts less than 24 hours or without a signature of infarction on the MRI. So we're picking up a lot more strokes these days because MRI is so much more readily available. So symptoms that may have only lasted 15, 20 minutes and would previously be classified as a TIA is now leaving its stamp basically on an MRI so we can classify that as a stroke because it has been damaged to the brain tissue. But really, they can be as serious as each other, both deserve the workup to find the cause to prevent, further stroke or TIA. But yeah, really the same sort of pathological process, but different only by time course.

Dr Gavin Nimon: 5:08

So really in the past when I learned that TIA was a minor event that was actually a prelude to a stroke, really with better imaging and as the imaging improves with years to come, we actually realise that all of these are strokes and just as bad as each other.

Dr Michael Waters: 5:20

Yeah, certainly we need to take TIAs seriously because it can herald a larger stroke. People with firstly, new diagnosis of atrial fibrillation or atherosclerosis in the neck, which might present initially with just transient symptoms. they might be at very high risk of having a large stroke. So these are the patients that you definitely want to pick up. TIA can be tricky because, for example, most patients that come through a TIA clinic in the hospital pathway, the majority of those won't actually be a true TIA or ischemia. There's often stroke mimics such as migraine and Other causes of vertigo such as peripheral vertigo and these sort of stuff. So there's lots of stroke mimics but if it is a true TIA, then yeah, definitely deserves the respect that, true ischemia would deserve because it can be a herald to something more serious.

Dr Gavin Nimon: 6:07

Okay. You've mentioned the actual difference in the actual incidence depending on the population. What other risk factors are there as well? And, actually one thought when we are talking about the different incidences, does collagen deficiencies influence the risk of hemorrhagic type strokes as well. Is that a factor too?

Dr Michael Waters: 6:24

Yeah, so there's a lot of risk factors. In general terms, the risk factors for cardiovascular disease very similar to the risk factors for cerebrovascular disease. The major cerebrovascular risk factors are the classic ones such as hypertension, hyperlipidemia, diabetes smoking, obesity, and then things like Alcoholism are also risk factors, renal failure, so they're the sort of, the classic ones that encompass the whole cardiovascular, cerebrovascular risk factors, and then there's more specific risk factors for certain types of strokes, so yes, collagen deficiency diseases can be risk factor for hemorrhagic stroke, for subarachnoid hemorrhage but also for vessel dissection, and vessel dissection can lead to to ischemic stroke, and then you've got your cardioembolic strokes as well and specifically looking at things like atrial fibrillation, which is the most the most common cause of a cardioembolic stroke.

Dr Gavin Nimon: 7:18

Okay. when you think of the actual risk factors, in the cardiac history, we use the Chadsvasc score to assess whether there's a risk of a cardiac event occurring. Is the CHADVAS score used in cerebral vascular accidents as well, or is it another type of score that's used?

Dr Michael Waters: 7:32

We, we don't specifically use Chadsvasc, although we use that for patients obviously with atrial fibrillation. We have other scores such as ABCD2 score, which looks at things like age, blood pressure and diabetes and previous stroke symptoms. There are scores that we use to classify an overall risk in someone with a TIA. And then a lot of the risk as well will depend on the imaging, which we do and the other tests that we do. For someone with a stroke, or stroke like symptoms, the key early investigations are a CT scan, and a CT angiogram, which gives us the parenchyma the tissue of the brain but also the vessels, the heart and the veins, the highways in and out. And that enables us to stratify risk quite early in an emergency setting by knowing what the vessels are looking like and knowing what the brain parenchyma looks like. So that's probably the most important early test to work out what's going on.

Dr Gavin Nimon: 8:23

So a CT angiogram as opposed to something like an MRI angiogram. Is that because a CT is a quicker investigation or is it just more easily available?

Dr Michael Waters: 8:32

Yeah, it's also a better investigation for blood vessels. It's much more readily available. In some countries such as France, then they often triage their stroke patients with MRI because it seems to be readily available in the big cities. But for us, yeah, the CT angiogram,, gives excellent vessels, luminal vessels, of what's going inside the blood vessel. If there's stenosis, if there's any thrombosis associated with that. And so that gives us everything we need. And then usually we'll do an mri, down the track to confirm. The MRI gives much better views of the actual parenchyma or the brain tissue whereas the blood vessels are well captured on a CT scan. In looking at a stroke, or someone who presents with acute stroke symptoms. To compare it to cardiac disease and our fields evolving in an interventional sense about 25 or 30 years interventional cardiologists. And so the direct comparison for a, for an ischemic stroke brain emergency is that heart emergency of the STEMI. So patient comes in with chest pain, and you want to see if the patient has a coronary vessel blockage or a STEMI. So similarly a patient comes in with. Neurological symptoms, so our chest pain is the neurological symptoms. Then the best first test, their best test would be the ECG to confirm the STEMI. Our best test to confirm the vessel occlusion for an ischemic stroke is is the CT angiogram. And then... Basically, then we can find the patients who are candidates for urgent reperfusion. Because we've also learned from our cardiology colleagues that, opening the blood vessel gives the patient the best outcome in the heart and in the brain. And so that sort of, urgent workup of the CT and the CT angiogram shows us which patients will benefit acutely from reperfusion and revascularization. Which gives them the best chance of a good outcome. And that's it for ischemic stroke specifically.

Dr Gavin Nimon: 10:16

yeah. So do you do a CT scan to assess whether there's a ischemic before or a hemorrhagic before you do the CT angiogram or do you just go straight to the CT angiogram

Dr Michael Waters: 10:25

We do. Yeah, you can, we go straight. So CT and CT angiogram. So CT gives us a lot of information. So CT, a plain CT scan will pick up hemorrhage and that'll be parenchymal hemorrhage or subarachnoid hemorrhage. So the different subtypes of hemorrhagic stroke. It'll show us in an ischemic stroke if the brain is already dead. If it's too far gone or if reperfusing the blocked blood vessel would be futile. So it shows us that as well. So the plain brain gives us a lot of information and then the CT angiogram shows us exactly what's going on with the vessels we're looking for an acute blockage which might be able to be reperfused, either through thrombectomy or through thrombolysis, we can. Probably talk about that in a bit, but also it's helpful for hemorrhagic stroke because hemorrhagic strokes can be due to aneurysm or subarachnoid hemorrhage, which can be due to obviously a cerebral aneurysm, which will be picked up usually on the CTA, arteriovenous malformations and other causes of intracranial hemorrhage will as well. We'll get a clue to those on the CTA. Some of those patients might require formal angiography, catheter angiography. But the CTA is a fantastic screening test for us to know what's going on with the vessels. And as well, more recently we're doing something called CT perfusion imaging, which basically shows us the area of thread and brain and shows us this key concept of what is the penumbra. So the penumbra is the salvageable tissue of the brain, which can be salvaged in an ischemic stroke if the blood vessels reopened. and so the CT perfusion imaging will show us that and show us which candidates will, which patients might benefit from acute reperfusion therapies.

Dr Gavin Nimon: 12:04

well take a step back, obviously a patient who we suspect is having a stroke, the most common symptoms you will see that they come in with, what would they be? And also how important is it to get to the hospital as quickly as possible?

Dr Michael Waters: 12:18

Yeah, it's very important. In a similar fashion, comparing to cardiology, we've learned a lot from our cardiology colleagues, not just in techniques and treatment and how to reperfuse, but also, educating the community about symptoms and how urgent symptoms are. So cardiology have done that very well with heart attacks and chest pain. And now there's, mnemonics and other catchy phrases to, try and identify or try and let the community know what the symptoms are of stroke. One is fast or be fast. So that'll cover a lot of the stroke symptoms. So B for balance, E for eyes or vision, F for facial droop, A for arm. S for Speech Disturbance, and T just for Time. BeFast, and the T showing the importance of time and getting to hospital urgently, so that you can be in a window for therapies. That covers most. Most of the big sort of symptoms of ischemic stroke of stroke, both hemorrhagic and ischemic, the problem is that brain is a very complex organ. And a stroke can affect any area of the brain. And so sometimes the signs or the symptoms of the stroke can be much more subtle. If you've got an isolated infarct in the hippocampus, you might just present with amnesia. If you've got a very small infarct around the thalamus or sensory cortex, it might just present with With some tingling or numbness on one side, so often the symptoms are more subtle, but the, a BeFAST type mnemonic covers, covers a lot of the symptoms that might indicate a larger stroke or one that would benefit from urgent reperfusion therapies.

Dr Gavin Nimon: 13:52

now obviously different areas will have different protocols, but in the Royal Adelaide Hospital, once a patient hits casualty and the A& E doctor appreciates that there could be a stroke occurring. What are the steps that they undertake? Do they undertake an ECG routinely to see for atrial fibrillation? Do we do bloods to look for coagulation profiles, etc.? What are the main investigations you'd want?

Dr Michael Waters: 14:16

Yeah, they do and it's a very coordinated effort when someone comes in as a stroke. So there's coordination between emergency and the EMS, the ambulance and the paramedics communicating with Ed initially and communicating with the code stroke team at the hospital. So there'll be some pre notification and so the team at the larger hospital can plan for them coming in and plan to get them straight through to the scan. So when they come in, yes, so they might already have a rhythm strip of the ECG from the ambulance. We will get a 12 lead ECG. in the emergency as well. But the most important thing is getting into the scanner to get the imaging. Because as you just mentioned before, time is very important. And time is brain is the, the phrase that's been used a lot in stroke. And that's because the acute therapies are time dependent, and the earlier you can deliver those acute therapies, then potentially the best outcome. So when they come into the ED there'll be a lot happening at once. There'll be brief history, there'll be IV access, there'll be an E C G. We'll make sure that there's a patent airway and that the patient's hemodynamically stable. And if that's the case, then they'll go straight on the ambulance stretcher into the CT scanner when they're in the CT scanner. Staff will be collecting some collateral information, time of onset, any anti coagulants and these sort of things that the patients might be on that might affect the treatment. and then as soon as we've got imaging, then we're making a decision about acute treatment. And that will depend on whether we're finding a ischemic stroke or hemorrhagic stroke.

Dr Gavin Nimon: 15:46

right. So ischemic head strokes are the more common ones. It's not the puggy scenario, but we'll talk about ischemic first of all. We've already talked about the defining the actual cause atrial fibrillation or... The actual other events and knowing whether it's a vascular disease. Once you've defined that there is an ischemic stroke, and you've actually done your CT and CT angiogram, what are the most common types of techniques you would then perform in those scenarios? Where do you go from there?

Dr Michael Waters: 16:10

Yeah, I guess we're trying to identify early the patients who will benefit from acute reperfusion or reopening the blood vessel. And there's two main tools that we have for that. So the first is thrombolysis. We've been doing that for 20 plus years in stroke care. And so thrombolysis lacks specifically on the fibre and to break down a clot. And the time window for that was initially four and a half hours. That's been extended to nine hours or nine hours plus in certain circumstances of favorable imaging. But thrombolysis is only so effective. So depending on the location and of the clot and the length of the clot, Thrombolysis may only work for around somewhere between 30 and 40 percent of actual vessel blockages to reperfuse the vessel. So it was recognized reasonably early on in the 2000s that thrombolysis, although it was a good treatment, it wouldn't work for, for everyone. And so In 2015, there were a series of five landmark clinical trials, pivotal trials that showed the benefit of endovascular therapy or clot retrieval, retrieving the clot through an endovascular route from the brain and showed the benefit of that in reducing disability. And the Royal Adelaide was involved strongly with one of those trials, EXTEND IA. The stroke and the interventional teams there in recruiting patients for one of those trials that were published in 2015. And the five trials showed a remarkable benefit for patients with large vessel occlusion or the blockage of a large vessel. And the number needed to treat was about two and a half. Which , in medicine is a very impressive number needed to treat, especially when we look at the actual number needed to treat for some of our other interventions and, and therapies in cardiovascular medicine. So incredible benefit in restoring function and reversing the stroke syndrome. So that's what's happening these days is the patients are going for endovascular therapy for clot retrieval. If they've got a large vessel ischemic stroke and salvageable brain tissue basically. And initially the window was four and a half hours and up to six hours in the initial trials. We've since shown trials that show benefit of endovascular clot retrieval up to 24 hours in select patients who have favorable penumbral imaging on their CT scan.

Dr Gavin Nimon: 18:25

So , when you do a clot retrieval, which vessels can you actually retrieve the clot from, and what does it actually involve, and how big is the clot you bring out? There's three questions that come to mind straight off as you're talking, and I'm in awe of this such amazing treatment.

Dr Michael Waters: 18:39

Yeah, and it is a remarkable treatment. I guess when I first went into neurology training, this was available only in clinical trials. And then you see the results of these patients who without clot retrieval would be left with a severely disabling stroke or even life threatening stroke. And some of these patients were leaving hospital a couple of days later. So quite a remarkable and seductive treatment, which is part of the reason that I went down a neuro interventional pathway. I really wanted to do what was being done because it seemed such a powerful treatment. And I guess once we've identified the vessel occlusion, they come straight upstairs to an angio suite. And, to compare to cardiology again, because, people have a reasonable understanding of what happens in a cardiac lab. It's very similar. So they'll come onto the angio table, there'll be an x ray tube around them. We'll get access either through the wrist or the hip, usually done under local anaesthetic plus or minus a little bit of sedation, but sometimes they do need to go to sleep for it. and then we'll pass tubes and wires up to the vessels of the neck and the cardiologist would go down and we'll go up basically navigate to the vessels of the brain. In terms of size and what we can do. So initially it was just the proximal large vessels that were involved in these trials. So we're talking internal carotid artery. M1, MCA, M1 occlusions, proximal M1 basilar artery occlusions. But now we're finding that we can go more distal more safely and techniques and technologies advancing so that our catheters and wires can go further out safely in the brain. Nowadays we're often retrieving clots from the more distal segments, M3 MCA segments in the ACAs as well, using smaller devices. And the clot that comes out is usually. Pretty small, to be honest. People, med students and trainees who come into the lab and you'll pull the clot out and they'll look at it and go, is that it? But, these are small vessels, they're, the vessels we're pulling them out of are usually somewhere between three and one millimetre, and so it doesn't take a big clot to cause a significant amount of neurological disability.

Dr Gavin Nimon: 20:35

It's amazing, it's really amazing. With the actual prevention side of things, I'll just, I'll get onto this for a sec while we're on the actual process. Obviously... We've talked about atrial fibrillation being a risk factor, but if you've got atherosclerosis in the large vessels, in the past, the people used to talk about doing endarterectomies. I Presume you can do stents and things for this. Also would wonder, also what about the people with vertebrobasilar insufficiency, and you've actually got blockage of the basilar vessels too. Can that be treated as well? There's plenty of people I see, where they extend their neck and they feel a bit dizzy. Is that a risk factor for strokes? And can that be treated as well?

Dr Michael Waters: 21:11

Yeah in the, in an acute stroke setting then the answer is quite simple. If you've got the blocked vessel, then the evidence is that if you retrieve and open that blood vessel then patients will do better. And some of the occlusions that we see there's the majority of strokes we see are embolic strokes. So the large vessel occlusion strokes are embolic, meaning they've come from somewhere else. So cardioembolic, atheroembolic for the, from the neck. If they're atheroembolic from the neck, then yes, sometimes we, to actually get access up there, we need to stent and balloon blood vessels to get access and so we treat the cause as well as removing the clot at the same time. To treat other conditions before they've had stroke. We still don't have great evidence for, so carotid stenting is one area where, they're starting to become equipoised with carotid endarterectomy, but we're probably still not quite there, so strictly speaking, carotid endarterectomy for carotid stenosis, symptomatic carotid stenosis is still the gold standard. But as devices and technology improvements, stroke risk of the procedure decreases, then we may get to the point where there's, there's complete equipoise or stenting is superior. Vertebra basilar disease is a bit more complicated just because the vessels, the vertebral arteries are smaller and often more tortuous. There was a trial previously looking at vertebral stenosis to balloon angioplasty, vertebral stenosis for symptomatic posterior circulation disease or insufficiency, but it didn't really show a clear benefit, , and so we don't know exactly where the line is yet with treating before someone has a stroke for these conditions. We know that medical therapies are effective but we don't know if we should be Stenting every patient that we see with a stenosis, the answer to that is definitely no and we're still finding the right patients to select and treat on a secondary prevention point of view, rather than treating them with, medicines and and lifestyle measures some of those patients, may benefit from intervention, but we're still, we still haven't worked out exactly who they are.

Dr Gavin Nimon: 23:10

And as I understand it, so then the embolic events are the main causes, and that's for either from atrial fibrillation or atherosclerotic vessels. And that's why treatment of cholesterol or an anticoagulation to reduce the risk of embolic events from atrial fibrillation, are the most important preventative measures at this stage. Is that correct?

Dr Michael Waters: 23:31

Yeah. Yeah, absolutely. Yeah. Preventative measures in general, the things that help with cardiovascular health will help with cerebrovascular as well. So daily exercise, limiting salt intake, balanced diet, some evidence for, Mediterranean type diet with, fish, vegetables, legumes, that sort of stuff. That's general advice that we would give everyone. And then there's other things that we can modify. For stroke, blood pressure is probably the big one. So blood pressure is where you probably get the biggest bang for your buck in terms of prevention, both. Because it's associated so strongly in a linear relationship with both ischemic and hemorrhagic stroke. And so there's definite evidence that if we're, treating blood pressure, treating hypertension, then we're, going to be reducing the incidence of stroke. So that's where you get often your highest benefit. But as well, treating cholesterol to target with statins, with with other exercise and diet as well as important. And then, as you say, if we identify certain factors such as actual fibrillation then specific antithrombotic therapy for that. With antithrombotic, generally people with atherosclerosis will be on antiplatelets and statins and that sort of medication. People with atrial fibrillation will be on anticoagulation. And most patients now without atrial fibrillation will be on the NOACs or the DOACs the novel or the direct oral anticoagulants as opposed to warfarin. Unless there's coexisting valvular heart disease or mechanical valves in. And so treating those things, gives, large benefit in reducing the risk of stroke. For example, someone with atrial fibrillation with a moderate CHADS VASc score being on anticoagulation versus not, their stroke risk can go from somewhere like 12 percent a year down to about, three to 4 percent a year. So there's a significant benefit in identifying things like atrial fibrillation and treating it appropriately.

Dr Gavin Nimon: 25:19

And in those patients fibrillation on anticoagulation, what's the risk of stopping it for a few days for an operation, which obviously is important for myself. We stop them for five days. Does that increase the risk significantly by stopping and restarting it, or is that a minor risk for those few days?

Dr Michael Waters: 25:35

Yeah. In the majority of patients, the risk won't be huge. If you think about the stroke risk over the year of 5%, and then, a few days taken away at the anticoagulation. So the stroke risk shouldn't be huge. The problem is that we often do see patients who come in with anticoagulation held just for a week with, with a stroke and with a large vessel occlusion. And so maybe we're a bit. Swayed by that because we're actually seeing the ones that do fall through the cracks a little bit. I think that's just, there's hundreds and hundreds who go off their anticoagulation and don't have a stroke in the perioperative period. So I think we're just, we're just capturing the ones that, that unfortunately do. I think for anyone who's at a, on the higher CHA2DS2 VASc score then we might need to consider bridging perioperatively, but even that's a little bit controversial because there was a, a trial back a number of years ago that said probably the bridging benefit for most of these patients, if they don't have a mechanical valve if they don't have severe OB dysfunction, the risk of bridging probably outweighs the benefit in terms of bleeding. so. We don't have a great answer. I think potentially the higher risk patients we, we might still need to bridge. But generally speaking, yeah, a few days off the oral anticoagulant is not a huge problem for most patients. Yeah.

Dr Gavin Nimon: 26:47

And then the other, before we move on to the hemorrhagic strokes, one other question that comes to mind is, What about the person on anticoagulation who actually is quite active in sport and they might be at risk of having injuries or knocks to their head. Maybe not Aussie rules football but they might be doing some mountain bike riding for instance. And they're on a anticoagulation. We're worried about the risk of an embolic stroke from atrial fibrillation, but what about the risk of a major hemorrhagic stroke from a head injury? When does the risk anticoagulation?

Dr Michael Waters: 27:18

Yeah, I think for someone who's having repetitive head trauma or high risk of trauma to the head, then the risk of subdural hematoma is another intracranial hemorrhage probably is too high. There's a lot of patients who we have. Who are younger patients who the atrial fibrillation is picked up and, these patients still, they still ride bikes, they still play, non contact sports, I'd be reluctant to be, playing a high velocity sport with potential head impact on on any coagulation definitely, but I think generally speaking, most other sports and pursuits, are going to be okay. Yeah.

Dr Gavin Nimon: 27:53

Moving on to the hemorrhagic stroke now. So, you said that's about 15 percent in Australia , of a stroke being hemorrhagic. How does that intervention vary once you pick up a hemorrhagic stroke? And I understand we've seen the video of Puggy, and it'll be different in the UK, so we're not discussing his case in particular, I'm just talking about in general, at the Royal Adelaide Hospital at this stage. So how does it vary what happens compared to an ischemic stroke?

Dr Michael Waters: 28:18

Yeah. Yeah, so hemorrhagic stroke, I mean it is quite different. In some ways with all the advent of the new treatment for ischemic stroke, hemorrhagic stroke has almost been the poor cousin and left behind a little bit. But there are some exciting changes to that which are happening at the moment, which we'll get to in a bit. Hemorrhagic stroke is quite diverse. Hemorrhagic stroke encompasses subarachnoid hemorrhage, which is often aneurysmal or from vascular malformations. It includes vascular malformations and other dural fistulas and things like that, which have bled into the brain. And then there's... The more common types of hemorrhagic stroke which are, um, parenchymal hemorrhagic strokes, and they can be either lobar. So in the peripheries of the brain, which is often associated with amyloid angiopathy, a condition that's more common over, over 65, or they can be In a traditional deeper location in the brain, which are traditionally your hypertensive hemorrhages, which we now rephrase as arteriolosclerotic hemorrhages, because they seem to have, they're not specifically due to hypertension, but they're due to a vast, a host of risk factors, which causes damage to the smaller blood vessels, which makes them more prone to bleeding. And so they're the general, that's the general classification for hemorrhagic stroke. Whereas ischemic stroke has the penumbra and that's a salvageable penumbra, the main issue for hemorrhagic stroke is that the blood itself is quite, or the blood breakdown products are quite toxic. And so the surrounding areas of the brain. have secondary damage because of this toxicity of the blood and the breakdown products of the blood. And so if you can prevent that, then you can potentially prevent further disability from stroke, from the hemorrhagic stroke. What we're looking at these days, the urgency for someone with a hemorrhagic stroke is just the same as someone with ischemic, with ischemia because Early things such as, tight blood pressure control can prevent hematoma expansion. As soon as you get hematoma expansion in a hemorrhagic stroke, then the outcomes worsen. So early blood pressure control. Whereas with an ischemic stroke, you actually want the blood pressure to be up a little bit. To feed to make that penumbra more salvageable. So tight blood pressure control reversal of any coagulopathy that might be present is really important as well early on for a hemorrhagic stroke. and a lot of these patients may need more intensive therapy or blood pressure therapy and infusions, such as in ICU So that's the acute medical management, which, is initiated straight away, an area where we're potentially going to see more treatment for hemorrhagic stroke is in early minimally invasive hematoma evacuation. So this is something that's under ongoing trials at the moment, and one of those is being run out of the Royal Adelaide, it's called Evacuate. and that sort of sums up the trial quite well, is that, the neurosurgeons will make a small craniectomy, and then with a surgery scope, which you can visualise the clot within the brain, then that will be Extracted under under direct visualization. So actually removing the clot so that there's less of that toxicity and secondary neuronal damage as a result of the blood sitting there. and it's shown some early promise in, potentially evacuating that clot early will limit the secondary deleterious effects of the blood and the blood breakdown products and prevent further, expansion of the neuronal damage. And so that, that's shown promise already in , one other randomized control trial looking at hematoma evacuation. And so it might be something that's done more routinely for hemorrhagic stroke to actually evacuate the clot and allow them to to start recovering earlier.

Dr Gavin Nimon: 32:03

If the breakdown products of the blood actually are toxic, is there any way of actually trying to minimise that breakdown products by giving, if it's acidic, can you put more alkali into the body to help cross the blood brain barrier and help reduce the acidic nature of that toxic component? Or is there any other ways you can neutralise those effects?

Dr Michael Waters: 32:23

Potentially. This is, this probably gets on to the, what I think is the next big step in, in stroke management in general. And that's, I think that the Holy Grail for stroke care, both ischemic and hemorrhagic is not going to be a new procedure that we do. I think it's going to be a medication. I think it's going to be some sort of neuroprotective agent. So something exactly like you mentioned. For ischemic stroke and hemorrhagic stroke, it will be something that when there is potential damage to the neurons that we're administering an agent, which is basically putting the brain on ice, so to speak and allowing these therapies to happen, either the evacuation of the clot, or the evacuation of the and allowing the brain more time, basically, and more potential then to regenerate. And then another area as well, which You know, we're looking at which hopefully might aid in recovery is looking at agents that aid neuroplasticity. We've talked about the acute stage of a stroke, but long term and as Puggy talked about, it just keeps over time, there's continued improvement and that's because of neuroplasticity. And the brain, despite having pathways that are damaged. New pathways will form and the brain will find new ways to create neuronal circuitry. And so medication which looks at enhancing that sort of neuroplasticity as well might be another sort of area where. Big gains are made in patient outcomes.

Dr Gavin Nimon: 33:46

That neuroplasticity just rings home to one of my favourite operations in orthopaedics and upper limb is when we do a tendon transfer from the index finger to the thumb, the patient wakes up and straight away moves the thumb. They don't have to think, I'm going to move the finger and the thumb moves, it just works straight away. And it goes to show how amazing the brain is. The actual neurology side of things, you've got Stephen Bacchi who was on our podcast earlier, coming through the ranks with his involvement in artificial intelligence. And I've asked these questions to a lot of my podcasters since we've had Stephen on, the AI working out sort of programs or algorithms to work out which patients actually benefit from which procedures. Is that already being used at the moment in neurology

Dr Michael Waters: 34:26

it is a little yeah, we, when we're using our perfusion imaging, we're getting maps that are, it spits out a map for us. It brings in all the data and shows us a map and it gives a basically a red and a green sort of a stop go type picture and says, this is the area of the brain that's good. This is the area that's bad. And then for certain clinical trials as well, that will then. Tell you if they're a candidate for that trial, which is how to help with recruitment and stuff previously. But as well, it gives you a immediate sort of, idea of what's happening with the MAP and the blood flow. The tricky thing is with AI and the perfusion imaging and the CT imaging is that at the moment, it's probably not yet as good as the human eye because the plain CT brain is often the most important scan and if you're missing subtle things on the plain brain such as small bits of blood and then you're looking to thrombolyze someone, that can have quite significant outcomes. From what I've seen, it's not quite good enough. For Yet and human is still better that may change, pretty soon. There's other areas where technology is going to not replace us, but hopefully work hand in hand with us. One of them is in specifically for neurointervention. One thing that we might be doing in the future is robotic neurointervention. And it might be, it might enable us to do procedures remotely. This has particular relevance to South Australia because our stroke service covers all of rural South Australia and the Northern Territory. And so some patients who may have the stroke in Darwin or Alice Springs the time to get them here You know, in the to get them to the Royal Adelaide for a clot retrieval, it could be four, six, eight hours depending on transport. So by that time, their penumbra may have completely infarcted. So remote robotic procedures have already been done in certain settings. They've been done in cardiology, but they're starting to be done in near intervention. And all you would need is an angiolab in one centre. So Alice Springs and Darwin could be perfect for that. And if you've got an angiolab and you've trained some local staff, then we could be doing our procedures robotically, remotely to extract these clots. So yeah, that's I guess one example of where technology might be helping us and working hand in hand with us.

Dr Gavin Nimon: 36:41

Wow. Obviously, you've done a lot of training to be at this stage. Who makes up the team, the code stroke team? Is it yourself? I presume there's a few of you that, on call . What is the actual team that make up for a stroke unit?

Dr Michael Waters: 36:56

Yeah, it's a great multidisciplinary team. We have stroke nurses who are often the first on hand in emergency to code strokes and they come they're specifically trained and they're very good at what they do. And they follow the patient from their first port of call and emergency to the time they head off to rehabilitation and they're involved with their care on the ward. They're doing swallow screens, they're, looking at imaging with us, they're liaising with with other medical staff. They're really important. On the ground in the emergency department, we have residents and registrars who are on the code stroke service. And they will be the ones helping to get the patient into the scanner as quickly as possible, getting the histories, getting the collaterals and that sort of stuff. We have a stroke neurologist that's on call, 24 7. and there's about six or seven of us at the Royal Adelaide at the moment who rotate that call. And then we have, at the moment we have four new interventionalists, at the Royal Adelaide who are doing the procedures for stroke. There's myself and there's two radiologists and one neurosurgeon. So we have a really diverse group and that really helps to have those three backgrounds covered with the interventional procedures as well. And then, we're very reliant on anesthetic colleagues. To, provide services for these patients when they do any of their procedures and often with, little to no warning. So our anaesthetic colleagues help us a lot. Intensive care help us post procedure often, to manage blood pressure, manage oedema and these sort of things. Neurosurgery may be called on occasionally for hemicraniectomies and other interventions that might be required to, to relieve pressure on the brain. And then, once the acute treatment is done, the interventional treatment, we're so reliant on our allied health team. So speech pathologists, OTs, physiotherapists, who will then be, spending the days and weeks ahead with these patients and getting the best outcome for them.

Dr Gavin Nimon: 38:44

Wow. And then they've obviously progressed to a rehab facility as well. Something like, at the moment, it would be Hampstead or the Repatriation Hospital in South Australia. and where they'd probably stay like Puggy did for some months. Rehabilitating, I presume. Is that, and there'll be another team involved in that as well. Yeah.

Dr Michael Waters: 39:01

Yeah. Some patients now are lucky in that they might leave hospital. 24, 48 hours after their procedure, they're the lucky ones who are, have been reperfused and and have, very minimal or no stroke. A lot of the patients, despite reperfusion or if they're presented later or with hemorrhagic stroke where the acute interventions aren't as progressed as what they are for ischemic, then yeah, some of these patients might need anywhere between days, weeks and months in rehab. And as Puggy said, outpatient services for months and years is actually probably still beneficial because even though you might see the most rapid changes occurring early on if you're still, pushing yourself and and, trying to get extra benefit, then, these patients will continue to improve over time.

Dr Gavin Nimon: 39:46

Yeah, it was lovely hearing that from Puggy as well. So. it's been brilliant speaking to you. It's been a really interesting. I always love every podcast I do. I go, this is the best one ever, but this has been brilliant hearing all this. So it's really, I really appreciate your time and amazing work you're doing. I'd like to thank you, Michael, for coming on our podcast and putting your time towards this and also all the efforts you're doing in that South Australia for this and covering Northern Territory. So thank you very much for all your hard work.

Dr Michael Waters: 40:15

thanks. Thanks for having me. It's been great.

Dr Gavin Nimon: 40:17

It's great knowing that there's someone dedicated on the other side when should anything like this happen to myself as well. So look, thank you very much Michael.

Dr Michael Waters: 40:25

Cheers. Thanks Gavin. All the best.

Gavin NImon: 40:26

Thank you very much for listening to our podcast today. I'd like to remind you that the information provided is just general advice and may vary depending on the region in which you are practicing or being treated. If you have any concerns or questions about what we've discussed, you should seek advice from your General Practitioner. I'd like to thank you very much for listening to our podcast, and please subscribe to the podcast for the next episode. Until then, please stay safe.