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Aortic Dissection Complications During Treatment
Zuby Syed • Dec 3, 2021 • 83 hits
Aortic dissections are a rare yet serious vascular complication that occurs when blood enters into the aortic wall via a tear in the wall’s innermost layer (tunica intima). The location of the dissection determines its classification into types: Type B aortic dissection involves a tear in the descending/abdominal part of the aorta, while a Type A aortic dissection develops where the aorta ascends from its branch point from the heart. The risks associated with treatment for aortic dissections include stroke, spinal cord ischemia and spinal cord paralysis. To minimize complications, it is important to manage heart rate and systolic blood pressure using anti-impulse therapy.
Interventional Radiologist Sabeen Dhand talks with Vascular Surgeon Frank Arko about Aortic Dissection Complications on the BackTable Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Brief
• Potential complications of aortic dissection treatments include stroke, spinal cord ischemia, and spinal cord paralysis.
• Spinal cord ischemia, though rare in the context of aortic dissection treatment, can cause permanent paralysis and sharply increases the risk of mortality.
• To minimize complications and address physiological needs in the hyperacute setting, patients may be best managed with medical therapy (anti-impulse therapy) to decrease resting heart rate to less than 60 bpm, and maintain a systolic blood pressure of less than 120 mmHg.
• When stenting, IVUS can be utilized to measure the maximal proximal and distal lumen diameter of the target. The stent size should be selected based on the larger of the two measurements.
Table of Contents
(1) Overview of Aortic Dissection Complications
(2) Tips to Avoid Aortic Dissection Complications
Overview of Aortic Dissection Complications
The three main risks associated with aortic dissections and their treatments include stroke, spinal cord ischemia, and spinal cord paralysis. Stroke is a highly dreaded complication of acute aortic dissections and is more likely to occur in older patients (>65), especially with a history of hypertension or atherosclerosis. Spinal cord ischemia is a rare but serious complication of aortic dissection or aortic dissection treatment that can cause sudden or delayed paralysis, sensory loss and urinary bowel dysfunction. This is important to note as these complications can extend hospital stays and contributes to higher mortality amongst patients.
[Dr. Frank Arko]
The problem with treating the patients and where everyone's concerned comes from is these three complications when you fix them. Retrograde Type A dissection, which basically turns you into medical therapy, now a sternotomy. There's a risk of stroke when you treat them. I think depending on the zone that you're treating, who's treating them, how many you've treated. That risk will vary probably somewhere between four to eight to 10%. Those strokes typically are not major disabling strokes, they're typically minor non-disabling strokes, but they're still strokes and we don't know the long-term outcomes of those. Then lastly the risk factor that everyone is greatly concerned about is spinal cord ischemia, paralysis. And to me, the worst of those three is really paralysis.
I mean, non-disabling stroke is bad. If you've got a retrograde dissection and you manage it from a team standpoint, you've always got a cardiac surgeon on board involved. You have to have that for that complication. Then I think the mortality or the bad outcomes from that is not terrible. I mean, if you catch it early, they can be repaired and fixed and they usually do okay.
Spinal cord ischemia and paralysis, I mean that is just a dreaded complication. It's happened to me. It's happened me with open surgery. It's happened to me immediately after. It's happened to me delayed for four weeks after I did TEVAR. And the problem with that is if they get permanent paralysis, it really is just a very, very tough way to live for someone who's older. And the risk of mortality long-term in those patients is relatively high, especially in the first six months after.
If we can figure out how to minimize or eliminate those three sort of major complications, then I think you can get into the role of everybody that has a dissection type B should maybe undergo TEVAR, but until we can sort of eliminate those or minimize those three things, that's why you will, I think, continuously have this argument over medical therapy, optimum medical therapy versus early TEVAR whether it's in the acute phase, the subacute phase, or the chronic phase.
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Tips to Avoid Aortic Dissection Complications
When treating aortic dissections, it is essential to assess the situation and need for medical therapy continuously throughout the treatment process to minimize any possible complications such as retrograde dissection or stroke. In the hyperacute setting, patients may be best managed with medical therapy (anti-impulse therapy) to decrease resting heart rate to less than 60 bpm, and maintain a systolic blood pressure of less than 120 mmHg. As the blood pressure reaches target pressures, specialists can use IVUS to accurately measure stent size by taking the larger number of the maximum proximal and distal reference lumens. Additionally, reassessment throughout the procedure is key as the use of adjunctive techniques may need to be utilized.
[Dr. Sabeen Dhand]:
That aorta and that acute phase is fragile and you mentioned, the retrograde dissections are what you worry about among other things. In a patient who you have to treat acutely, they're coming in, they have rupture or amount or malperfusion that's requiring treatment then and there, what are some tips that you do that you try to avoid the complications like a retrograde dissection or stroke? Do you get in and out? Do you do just TEVAR? Do you dabble in the petticoat in that or use any adjunct techniques?
[Dr. Frank Arko]:
I think those are great questions. I think it's a little bit dependent upon what I'm seeing when I get in there. I think that if you've got the complicated dissection, I think about 15 to 20% of those patients will need some sort of adjunctive techniques. I guide everything as I go in. So I don't go into the procedure saying, "I'm going to do these five things." I start in the process of what I'm going to do, re-image, and then decide what needs to be done next.
So if you come in, I need to treat you hyperacutely. First, I want to get your blood pressure appropriate. So appropriate anti-impulse therapy. Depending on the level that I have to go up to. So if I have to cover left subclavian, I may or may not pace you. So I like to deploy under pacing. I just think it can be a little bit more accurate. We do some Type A dissections as well with TEVAR and some ascending work. So getting the ability to do TEVAR before you have to get to that stage and understanding how to do it, I think is a nice bridging to get to the next level if you want to go into zone one or zone zero.
So pacing I think is sometimes important. Two: IVUS through the case. So pre, post, and then deciding what you want to do next. To minimize that risk of retrograde type A dissection, I typically will tend to base my imaging off of IVUS. And again, if it's hyperacute and they come in with a blood pressure like 220, the thoracic aorta is much bigger. So I think you tend to oversize too much. So when you get them an appropriate anti-impulse therapy, you go back in there by IVUS. Their aorta is maybe 30, 31 rather than 40 or 42 when they come in.
So we can then decrease the size of the stent graft. Because if you're putting in, 40, 42 stent grafts in dissections, you really raise the risk of retrograde Type A dissection. So I think IVUS is important. When you come in and you talk about petticoat, I think there's certainly a need for petticoat in certain patients which is typically when the true lumen remains completely compressed through the visceral segment and the infrarenal. There have been sometimes maybe once a year and this is pre the petticoat when it was FDA approved. So it was approved outside the US first where we would have to put stents through that visceral segment to get it open.
But I'd say it's like 1 or 2% for that. I find that if we just go up do the TEVAR, we get pretty good expansion of the true lumen all the way through the visceral segment. We tend to be a little bit more aggressive in the amount of thoracic coverage that we do and this has again been a little bit of my own evolution over 22 years where I used to go in, put one piece. You hear people talk about it. So I just put in a single 10 piece for the TEVAR. I cover the entry there.
I used to do that but then I'd be back at six to eight weeks because it'd have aneurysmal degeneration distal to that because I was deploying in the still disease segment through the mid thoracic aorta that talk about stent graft induced new entry tears. It's not from stent grafts, it's just disease. So I now have a tendency to go further down. I tend to go about two to three centimeters above the celiac. You get into more normal aorta. I think you also get much better aortic remodeling, thoracic, long-term but then you bring in a little bit of risk of increased spinal cord ischemia.
We haven't really seen that there, but we certainly have it. We can usually recover it, but the data in China in which they've got a lot, when they've gone down that far ahead slightly increased risk of spinal cord ischemia. So when you become a little bit more aggressive, you have to manage that complication. Then once I do that, then I take a look at the visceral segments sort of see what's going on. I tend to be a little bit aggressive on treating the viscerals in the renals.
So if I see something that's even a little bit dynamic obstruction or if you have a static obstruction, I'm going to treat you for sure, but I will typically go in and put in a stent. I like to use covered stents in those areas. One, the vessels are big. They track easily. But with the covered stents, there's usually some fenestrations there that you can cover and you can sort of get better aortic remodeling if you can shut off that reentry flow into the false lumen off of visceral or a renal.
Then lastly if I had to, I put a petticoat in but that's like one, two, three, maybe at most 4% for me. I think there's more and more people putting it in. Maybe it's fine. Maybe I'm missing the charge on that one a little bit. But in my own practice, I haven't really felt the need to use it.
Dr. Frank Arko
Dr. Frank Arko is a practicing Vascular Surgeon and the Chief of Vascular and Endovascular Surgery at Sanger Heart & Vascular Institute in Charlotte, North Carolina.
Dr. Sabeen Dhand
Dr. Sabeen Dhand is a practicing interventional radiologist with PIH Health in Los Angeles.
Cite This Podcast
BackTable, LLC (Producer). (2021, July 16). Ep. 142 – Type B Aortic Dissections [Audio podcast]. Retrieved from https://www.backtable.com
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