Aortic Aneurysms: Endovascular Stent Grafting – Part 2
Guest: Dr. John Ikonomidis – Cardiothoracic Surgery
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I am Dr. Linda Austin. I am interviewing Dr. John Ikonomidis who is Associate Professor of Cardiothoracic Surgery here at MUSC and is director of the Heart Transplant Program. This is the second of a two-part series we are doing on endovascular stent grafts for aortic aneurysms. Dr. Ikonomidis, in the earlier podcast we talked about who is a good candidate. Let’s talk about the procedure itself. If I were a patient, what would I do, let’s say, before coming into the hospital, or would this be an emergency procedure, typically?
Dr. John Ikonomidis: This is typically an elective procedure. Occasionally we do stent grafts for emergency conditions. In fact, it may actually be better than open surgery in emergency situations because of the less invasive nature of it and, also, the fact that it is often possible to do the procedure faster than an open surgical procedure. Otherwise, for elective stent grafting, which is usually the case, the patient does not have to do anything specific before surgery. However, if the patient is on any anti-platelet agents like aspirin or plavix, which are pretty commonly used, we recommend that they stop those about a week before the operation, just to minimize the risk of bleeding. Other than that, the patient is instructed to not eat or drink anything after midnight. Additionally, because this is aneurysm disease that we are talking about here and strenuous physical activity can potentially predispose to rupture, we recommend that these patients reduce their activities to, really, nonexertional type activities.
Dr. Linda Austin: Now, on the day of surgery, is this done under general anesthesia?
Dr. John Ikonomidis: The vast majority of the time, yes.
Dr. Linda Austin: It is? Okay, so, it is pretty easy from the patient’s point of view. What do you do though, what are your first steps in this procedure?
Dr. John Ikonomidis: So, it is always possible that we may have to convert to an open procedure if something happens with the stent graft. Although, I must say, that is very unusual.
Dr. Linda Austin: Open, meaning you actually make an incision in the abdomen or the thoracic area of the patient, the chest area?
Dr. John Ikonomidis: Yes, in the thoracic area, right. We make sure, once the patient is anesthetized and has a breathing tube in and is completely asleep, we prepare, with sterile iodine, the entire chest and abdomen and the lower extremities in preparation for anything that we have to do. The majority of the time, we are deploying this through the large artery in the groin, called the femoral artery. We do that through a relatively small incision, only a 2 to 3 inch incision, which is well tolerated compared to a large chest incision that is required to repair this open. Once the patient is asleep and we have everything prepped out and sterile drapes put on, we have specialized imaging equipment, x-ray equipment, we use to image the aorta in real time; it is a real-time x-ray unit.
Once we have that up over the patient, we insert an IV into the artery on one side of the groin through which we can advance special tubes called catheters. Through those catheters, we can inject dye, and we take real-time pictures and it gives us a real-time picture of the aneurysm and what it is that we have to exclude. Through the other artery, once we have that picture, we put in a second larger IV, we call it a sheath, and through that sheath we can put other things. One of the things we put in is a large introducer device that the stent graft goes through. That introducer device is up to 8 mm wide, almost a full centimeter, which gets back to what I was talking about in the first podcast. You have to make sure that you have blood vessel anatomy that is of the appropriate size and is not too tortuous, does not go in too many curleques, so that it will be easy to advance this device through, minimizing the risk of damage. The most common complication of endovascular stent grafting is blood vessel damage.
Once we have the introducer in, we can image that with the x-rays to make sure that it is in the correct location. Through that, we advance the stent graft itself under direct vision, through the x-ray, until we get exactly to where the aneurysm is. Then, it is a relatively simple matter to engage the deployment device. The stent graft opens up and it seals the aorta from the inside and excludes the aneurysm. Following that, we put another catheter, another line, up through the stent graft and we inject some dye into the aorta and get a picture to make sure that we have sealed off both sides of the aorta and that the aneurysm is completely excluded. We have special balloon dilators in which we inflate the balloon inside the stent graft and expand it open and make sure that it is nicely sealed on both sides of the aneurysm so that there are no leaks past it. When we have confirmed with an angiogram, which is injection of dye within the aorta, that the stent graft is properly deployed in the right location and that there are no leaks, the surgical procedure is complete. Then, we pull all of the devices and sheaths out and close up the holes in the artery and then close up the holes in the skin.
Most of the patients have their breathing tubes out in the operating room which is very different from open surgery, in which it may be one or two days before their breathing tube comes out.
Dr. Linda Austin: Now, if everything goes well, let’s say, in a very simple uncomplicated case everything has gone beautifully, what length of time would that take?
Dr. John Ikonomidis: From the time the patient enters the operating room to when the patient leaves, it might be somewhere around 90 minutes or less.
Dr. Linda Austin: So, pretty quick?
Dr. John Ikonomidis: Pretty quick.
Dr. Linda Austin: Then, how long do they stay in the hospital?
Dr. John Ikonomidis: They stay in the hospital two or three days, not much more than that.
Dr. Linda Austin: How long until they are back to full activity, till they could play tennis or do something like that?
Dr. John Ikonomidis: I would say about two weeks or so.
Dr. Linda Austin: Wow! That is amazing. What is the age range in which you have done this procedure?
Dr. John Ikonomidis: We have done them in patients age 40 to 85. Some of it has to do with patient preference and some of it has to do with evaluation of other conditions, as we discussed.
Dr. Linda Austin: I am sure you make a recommendation and then the patient, obviously, makes a decision at that point. Now, I am aware that one of the issues, and you mentioned this in the earlier podcast, is choosing between an open, sort of traditional, surgical procedure versus this and how long it will last. How long have these stents been around? How much experience do we have with them?
Dr. John Ikonomidis: The concept of stent grafting started in the early 1990s, in the thoracic aorta. The first stent grafts were probably deployed in the mid-1990s, between 1995 and 1997/1998 and 1999. Around that time, companies got interested and actually started designing some more uniform grafts which were involved in trials. The first stent graft that was actually FDA approved for deployment came on line in around 2006/late 2005. So, a device that is actually FDA approved for use in aneurysms has only really been around for about three years.
Dr. Linda Austin: When patients ask you how long they can reasonably expect this to last, I am sure it is hard to know because if they were to last 20 years, we do not have that much time and that much experience. But, what kind of answer do you give to what reasonable expectations might be?
Dr. John Ikonomidis: Obviously, at the front end I tell them that I am not certain, which is why I tend to reserve these four cases in which open surgery is not a very good option. But, reasonably, I think we are looking at probably about a 10 or 15-year durability and perhaps more. Trials will allow us to evaluate that further, but I think that is sort of where this is going to be.
Dr. Linda Austin: What are typical side effects, adverse consequences?
Dr. John Ikonomidis: The immediate side effects have to do with things like allergies to the dye that is used which is, thankfully, quite rare, but it is something you have to be aware of in terms of these procedures. Vascular complications, in other words, damage to the vessels that need to be repaired, happen about 20 percent of the time. There are problems with migration of the stent graft, requiring a re-operation and deployment of another graft to seal off a leak, development of late leaks across the stent graft in which we have to re-deploy stent grafts. In a small percentage of patients, even though it looks like you have completely sealed off the aneurysm, there is a leak of fluid across the stent graft fabric itself and the aneurysm continues to dilate. In those circumstances, it is controversial as to whether or not you should try to re-deploy stent grafts or actually just undergo open surgery. There is a risk of paraplegia associated with stent grafting. Paraplegia is what happens when the spinal cord dies and you are unable to move your legs after the surgery. This, historically, has been a big problem with open surgical approaches, where we actually make a cut in the chest. Depending on the size of the aneurysm in the chest, there is up to a 20 percent chance that you can develop this.
With stent grafting, that risk has been substantially reduced. Many centers report less than a four percent incidence of paraplegia with stent grafts and some actually have a 0 percent incidence. So, that is very encouraging. There are other complications, including fistulas. Sometimes a stent graft can put so much pressure on the aorta that it erodes into other structures. For example, up in the chest, it could be the breathing tube, the trachea or the food tube, the esophagus. So, you can get fistulas and those can be pretty catastrophic but, thankfully, those are very rare. There are also device-related complications. Sometimes the use of those devices inside the aorta can damage the aorta and cause an aortic dissection which is another fairly serious disease process of the aorta. There is also a percentage of patients, probably up to about 30 percent, that develops a fever syndrome after a stent graft. They feel a little bit ill and they have a fever. We work them up and make sure they do not have specific infections, but at the end of the workup, we find nothing. This so called postimplantation syndrome is treatable, usually with aspirin or ibuprofen for one or two weeks and then goes away.
Dr. Linda Austin: Clearly, we have a very active stent graft program here that you run, Dr. Ikonomidis. I understand that we are one of the few places in the state that does have that. Is that correct?
Dr. John Ikonomidis: That is correct. We offer endovascular stent grafting as part of what we believe to be a complete thoracic aortic surgical program, where we will be able to offer you any and all of the currently available treatment options for aneurysm disease and I believe that is important. If you are evaluated by us, we will tailor the appropriate surgical therapy, or medical therapy, to you and not slot you into a procedure that we have but not something else. We believe that we will be able to provide you with the best care for your thoracic aneurysm.
Dr. Linda Austin: Thank you very much.
Dr. John Ikonomidis: Thank you.
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