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Aortic Dissection Types
Zuby Syed • Oct 15, 2021 • 73 hits
Aortic dissections are caused by separations in the layers of the aortic wall due to the onset of an intimal tear. Aortic dissections can be classified depending on the location of the intimal tear, extent of involvement of the aorta, and duration of time from initial clinical presentation. The classifications can dictate medical management and surgical versus endovascular treatment.
Interventional Radiologist Sabeen Dhand talks with Vascular Surgeon Frank Arko about Aortic Dissection Types and Treatment on Episode 142 of the BackTable Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Brief
• Aortic dissections can be classified by either the Stanford or DeBekay classification systems, which are based upon location of intimal tear and extent of involvement of the aorta.
• Acute aortic dissections are distinguishable from subacute and chronic aortic dissections at an arbitrary time point of two weeks from initial clinical presentation, whereas subacute is 14-90 days and chronic is over 90 days from initial clinical presentation.
• Risk of aortic dissection treatment includes stroke, spinal cord ischemia and spinal cord paralysis.
• Initial medical management for aortic dissection includes stabilizing heart rate and blood pressure. After the aortic dissection procedure, obtain a CTA immediately, and then again six weeks out. If normal, follow up again after six months.
Table of Contents
(1) Aortic Dissection Types: Stanford vs. DeBakey
(2) Aortic Dissection Types: Acute vs. Chronic
Aortic Dissection Types: Stanford vs. DeBakey
Aortic Dissections can be classified by two classification systems: Stanford or Debakey. The Stanford classification has two types (Type A or B). Type A includes any aortic dissection that involves the ascending aorta, regardless of the origin of the dissection by intimal tear. Type B includes all dissections that do not involve the ascending aorta. Under the DeBakey classification, there are three types (Type I, II or III). Type I originates in the ascending aorta and propagates to include at least the aortic arch, though it can travel distally beyond it. Type II both originates and is confined by the ascending aorta. Type III originates in the descending aorta and can travel either retrograde to include the aortic arch or travel anterograde down the aorta.
[Dr. Frank Arko]
If you're going to talk about dissections, I would talk about first Type A and Type B. I think that's one that you need to understand. I think that's makes it relatively simple. I went to Stanford so I'm going to use just the Stanford and not the DeBakey. I think the DeBakey is a little bit more difficult to understand and define. I really focus on the on the Type B and and maybe the residual Type B following the type A. It's just a difference in where the the tears occur.
So I train a lot of fellows and residents, and I get to be a little bit of a stickler in some of the nomenclature for the repairs. Often times, when someone's younger and talking to you about a dissection, they're like, "Well, I got a symptomatic dissection, or I got a symptomatic dissection with a lot of pain." The first thing I said, "If you're going to get into the world of dissections, the first thing you need to really talk about is the complicated versus the uncomplicated.
Now, you can get into a whole lot of definitions about whether those are even good terminology. And to be honest with you, I have some problems with the complicated versus the uncomplicated nomenclature. But I think that is most important. The uncomplicated really, they just have a dissection and they don't really have much in the way of anything else causing them a problem.
I think the number of those patients that have the truly uncomplicated dissection, I think they're there, but they're relatively infrequent when you really start to take a look at the imaging and how the patients are being managed. I find that there are a number of complicated dissections that would get downgraded, if you will, into the uncomplicated in patients who have ischemia to a kidney.
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Aortic Dissection Types: Acute vs. Chronic
Aortic dissections can be further classified based upon time from initial clinical presentation. Acute aortic dissections fall within 14 days of initial clinical presentation, while chronic aortic dissections are 90 days after initial clinical presentation.
[Dr. Frank Arko]
As a surgeon who who sees more the chronic. Acute, so in the first 14 days, gets a sub-acute and that definition changes. So depending on inclusion, exclusion criteria or varying guidelines, it could range from 14 days to 30 days or up to 90 days. Then you got the chronic, which is longer than that. The problem with those definitions as well is because they start to talk about the lamella or how the tear is and what you can do from the endovascular standpoint versus open surgery is then getting into that chronic dissection.
So I want to treat the early stuff to try to minimize someone getting to the chronic phase. That chronic phase in which it becomes the dissection that has now become aneurysma from an endovascular standpoint really becomes a complex repair no matter who's doing it, and even if you've done a lot. The reason for it is, is the top part is all the same. Nothing changes. It's cover the entry tear. You typically have a normal neck. Maybe you've got to cover the left subclavian. Maybe you've got to do a bypass or revascularize the left subclavian. However, you want to do it, whether it's with a fenestrated graft, in situ repair, or surgical bypass. The problem gets on the bottom side.
And when you come to the bottom side, sometimes I think you almost take the chronic dissection that's been slowly getting aneurysmal because you got the inflow and then you got re-entry tears down at the bottom. Sometimes when you go in with the chronic phase, you go up to the top, you cover the entry tear, but you don't have any ability to fix the stuff on the bottom. When that happens, I think in a select group of patients, you get this entry flow, but is now on the bottom.
You start to see this a little bit more rapid increase in size of the thoracic aorta. So then you got to get in that more complex repair of a four vessel fenestrated graft. That becomes a very difficult repair in anyone's hands. I think what happens if we can treat those earlier ones, we minimize those operations that are needed in the chronic phase and what happens is in the chronic phase, you never eliminate the three risk factors that you take, if you fix them early.
You still have that risk of stroke, you still have that risk of retrograde, and you still have the risk of spinal cord ischemia. So that's why I like to treat more and more type B's earlier to eliminate that risk of needing that more difficult complex repair. I think most large institutions can treat and treat well the type B aortic dissection, which certain protocols and instructions, and doing it as a team system. When you get in that more complex repair, that type 2 thoraco-abdominal, which is from the dissection, that I think is probably limited to about 15 to 20 centers, maybe more. Within the US, that actually can really do it well.
The problem with that is just patients like this all over the United States trying to seek places to go and then they can't afford to get where they need to go and they want to do it wherever it's being done. Maybe physicians can say, "Oh, I think I can do it, but I haven't done that many, but patients want to do it." I think you get into issues with outcomes specifically mortality and spinal cord ischemia and in those patients being treated at not large volume centers.
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
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.