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Medical Intel

Aug 23, 2018

Lost time = lost brain function when it comes to patients who have had a stroke. Dr. Rocco Armonda discusses mechanical thrombectomy, a minimally invasive procedure that can provide lifesaving treatment for strokes caused by large blood clots.



Introduction: MedStar Washington Hospital Center presents Medical Intel, where our healthcare team shares health and wellness insights and gives you the inside story on advances in medicine. Today, we’re talking about mechanical thrombectomy with Dr. Rocco Armonda, Director of Neuroendovascular Surgery and Surgical Co-Director of the Neuro Intensive Care Unit, MedStar Washington Hospital Center. Mechanical thrombectomy is a breakthrough procedure to quickly and effectively remove blood clots from the brains of stroke patients using a stent retriever device. The procedure often is used when the patient is suffering a large-vessel occlusion.

Host: Dr. Armonda, what is a large-vessel occlusion?

Dr. Armonda: Right, so what this refers to is basically the major conductance vessels of the brain, the major vessels that basically bring blood into the brain, so we’re talking about mainly the carotid artery, the middle cerebral artery and the posterior circulation—it’s primarily the vertebral artery and the basilar artery. These are the major conducting vessels that we’re looking at, and what studies have shown of recent is that mechanical intervention with the use of catheters, a combination of mechanical devices called stent retrievers and aspiration techniques, have actually dramatically changed outcomes to the point where we basically are seeing a success rate of on the order of 70 to 90 percent if we can get to patients early enough. And, we’re talking about huge life savings in terms of preventing paralysis, preventing them from death, preventing them from being bedridden, maintaining their independence, their ability to speak, communicate, relate to their families. An individual who is typically in the prime of their life or just post-retirement, and they go from being paralyzed on one side of their body and unable to speak, to basically speaking and moving and walking and back to their normal baseline, and that’s pretty dramatic. But it takes a well-organized system to do this. And, it really took a number of studies that basically showed at the highest level of evidence dramatic changes in terms of outcome. With those vessels who have large-vessel occlusion, you can get to them in a very rapid fashion, and in fact, the core of the infarct was smaller than the tissue at risk.

Host: One of the better-known stroke treatments is tPA, which is a medication given through an IV to help dissolve blood clots. Is mechanical thrombectomy a replacement for tPA?

Dr. Armonda: You know, when IV tPA first came out, the clot-busting medication was given through the IV. That was the only FDA-approved intervention. And now, you know, the paradigm has shifted, so it’s not that mechanical thrombectomy replaces IV tPA; we actually do both in a lot of cases. There’s three different scenarios. There is one scenario in a patient where we’ll start the IV tPA and you might shift them to a place that does mechanical thrombectomy. There’s another scenario where you start the IV tPA while you’re ongoing doing the mechanical thrombectomy. And, then there’s a third scenario which is a patient who can’t qualify for IV tPA. Let’s say they have had recent surgery. Let’s say because of other time-window reasons you can’t exactly place the onset of the stroke. So, it’s beyond perhaps the 4.5-hour period, so those patients will go straight to mechanical thrombectomy. So, the idea is that mechanical thrombectomy is not competitive with IV tPA; it is complemented. You know, there’s some cases where, honestly, we started the IV tPA, we do the mechanical thrombectomy, and given the fact that they started the IV tPA, the clot suctions up much quicker, and/or we’ll do an angiogram and the clot’s now gone, in rare cases. But, you know there’s situations where you don’t want to stop and wait and see if the patient gets better because you’re already putting into that situation of 20 percent-plus decline in their outcome. IV tPA is usually given earlier, typically under three hours, but up to 4.5 hours, but if you have a patient who is beyond that 4.5-hour period, but whose imaging shows evidence of a large-vessel occlusion, but still preservation of a large portion of brain, and that the core of the infarct doesn’t exceed a certain volume, those patients may not be able to get tPA, but we can do a thrombectomy. And, then you have another group of patients who may have just woken up from a stroke. Those wake-up strokes beyond the typical 6 hours may also benefit from mechanical thrombectomy.

Host: Is six hours the typical window for a patient to receive mechanical thrombectomy?

Dr. Armonda: The sooner, the better. The way it works, basically, is that the best outcomes are those patients treated under three hours. Time is brain here. Each 30-minute period of time lost is 10 percent loss of good outcome. So, if you compare outcomes in patients who are treated within a three-hour period versus patients within a five-hour period, the difference could be as much as 70 percent good outcome versus 50/50 percent good outcome, and maybe even lower. So that means that you start at 50 percent and then it decreases from there at the five-hour mark. Beyond five hours, it may actually get lower and lower, so five hours is usually, you know, the optimal time period that we really shoot for. But, the idea here is that you want to be able to get to patients as quickly as possible. And, you know, there’s a couple areas of delay. You know, one of the areas of delay is in patients and families just recognizing signs of a stroke. Does the patient have problems with their speech? Does the patient have a problem with a paralysis? Does the patient have asymmetry in terms of their face? Is it arm weakness? Is it leg weakness? Is this something new compared to before?

Sometimes, it could be a level of consciousness problem, and if they have problems speaking, they may not necessarily be able to communicate this, especially for elderly patients who may live alone. The other problem is that we’re also seeing an increase in stroke in the young. There’s been some reports on this just recently. And, the problem with stroke in the young is that, two things. One is that the individual is young and he may actually deny or she may deny that they are actually having a stroke. They may attribute it to, you know, a muscle spasm or problem with overexertion. The other problem is that because they are in the younger ages, when they present to the emergency room, they may not get as rapidly triaged because an ER physician may not be thinking of a stroke in a young person. But again, sudden-onset symptoms involving a paralysis, you know, the evidence of eye preference where they may be looking to one side, paralysis of their arm, leg, and/or face asymmetry should make, you know, ER physicians, family members, EMS think of a large-vessel occlusion. And it’s different. You know, there’s not many hospitals in this area that have the ability to do emergency thrombectomy. You know, emergency thrombectomy is a very specialized procedure that is best done by practicing neurointerventionalists, people who are using the tools, the devices in that circulation, day in and day out. It’s not appropriate for a peripheral interventionalist or cardiologist, or someone who dabbles in peripheral vascular to now be trying to attempt mechanical thrombectomy in the delicate vessels of the brain. They’re at much more risk for causing damage.  So, it demands a lot from a hospital system. 

Host: How do the specialist teams work together to treat people who need mechanical thrombectomy?

Dr. Armonda: So, it’s a—it’s a critical balance of multiple different team members. We’re a comprehensive stroke center, the first one in DC. We’ve had this ability to sort of bring the expertise and scientists from NIH Stroke Team together with the neurointerventionalists and with our capacity to do this emergency work, and it transfers from emergency work from trauma to emergency work to stroke care, and it goes hand-in-hand. It means that the hospital system has to be very well streamlined in terms of the efficiency of receiving patients, rapidly imaging patients and being able to have a whole team of individuals to treat this individual. So, it’s not just the neurointerventionalist. It’s also, you know, the stroke team, neurologists who are screening these patients. It’s the imaging team in terms of CT or MR personnel from radiology who are screening them. It’s the anesthesia team who is supporting the anesthetic during that patient’s neurointerventional procedure. And, then the follow-on care in terms of management in the ICU is absolutely critical. You know, you can win the battle in the angio suite and open up the vessel, but if you can’t control the blood pressure, you know, you’re at risk for that patient converting this dry stroke into a hemorrhagic stroke, and that could be fatal. You know, a lot of patients don’t know the difference between a primary stroke center and a comprehensive stroke center. And, they see a sign that says “stroke center,” so they bring their loved one to the closest hospital, and that might be a block away, a mile away, but they realize that that patient can’t get – their loved one can’t get an emergency thrombectomy at that hospital, and then they have to be transferred. So when they look at studies where patients had to be transferred, it was a minimum of 1 hour in the best of scenarios for that patient to then make it to another hospital, so that’s already at least a minimum of a 20 percent decline in outcome. So that’s why it’s so important in terms of, you know, getting the message out there to EMS, getting the message out there to other clinicians to ensure that, you know, rapid transfer is made and rapid evaluation is made, patients are brought to the right place.

Host: So, it’s really a combination of fast action and the hospital team working together? 

Dr. Armonda: The idea is, once you see the patient in terms of early warning systems throughout your network, you want to start mobilizing the neuro-rescue. You want to start mobilizing the thrombectomy team. That means, you know, a team of nurses, technologists, anesthesia and the neurointerventionalist. And the unique thing about what we have here is that we have radiologists, neurologists, neurosurgeons all working together in the same procedure. So, there might be a patient who presents with a stroke and it might be a neurosurgeon doing the thrombectomy because he’s on call that night. Or it might be a radiologist doing it, or it might be a stroke neurologist who is neurointerventional-trained because all of us, from different specialties, work together in the same arena, and we work together day in and day out, so we have a very comprehensive team approach.

Every single step of the treatment care has to be the most efficient workflow. It’s like a car pulling in for a pit stop. You know, you have to work in parallel. You can’t work in series. Everybody has to have a job and they have to sort of approach at the same time. So, in trauma, we do the same thing. We have to be able to rapidly get the patient from the door to imaging, and then from imaging, if they’re a candidate, to the interventional suite. You know, and our interventional suites here are state-of-the-art. We have two biplane machines. What biplane means is that you’re imaging both from the frontal plane and the lateral plane. You know, these are basically endovascular operating rooms. And, both are set up for anesthesia, so we could literally run two thrombectomy cases at the same time. There’s very, very few institutions around the country that could do that, and we have the personnel to do that. So, it’s not just, you know, have the rooms because an x-ray machine can’t run itself. It’s having the nurses, it’s having the technologists, it’s having the anesthesiologists. And, the beauty of our anesthesiologists, they are very adept to patients with multiple comorbidities. They are very adept of emergency airway, you know, from all their experience with cardiac patients, all their experience with trauma patients. Anesthesia is one of the most solid services that we have here. And you have to have that because while you’re busy trying to get access into their arterial system and get your catheters up there, you want someone who is maintaining the patient’s blood pressure, who’s securing the patient’s airway, who’s ensuring that the patient remains immobile so that you’re not dealing with a moving target. You know, and that’s a difficult situation because these patients are not intrinsically healthy patients. These patients usually have problems with their lungs, usually cardiac problems as well, variations of all kinds of blood pressure problems, kidney problems, and so forth. So, it takes a real level of sophistication and team approach.

Whenever I see a patient come back in a clinic or a patient who, and family, comes in my office and thanks me, I try to redirect those patients back up to the ICU so they could visit with the nurses who took care of them. They could thank the PAs who were part of their care, and the nurse practitioners, because we never do anything here as a single individual. Everything that we do is as part of the team. And, the best things we do are with the best teams, and I think we really have one of the best teams here.        

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