Aorta Surgery: An Overview of What You Need to Know

Podcast Transcript

Announcer:

Welcome to Love Your Heart, brought to you by Cleveland Clinic's Sydell and Arnold Miller Family Heart, Vascular and Thoracic Institute. These podcasts will help you learn more about your heart, thoracic and vascular systems, ways to stay healthy, and information about diseases and treatment options. Enjoy.

Lars Svensson, MD, PhD:

Thank you for joining us. I'm Lars Svensson, and I'm Chairman of the Heart, Vascular and Thoracic Institute here at the Cleveland Clinic. I trained here many years ago, and then worked in Houston and Boston and came back. And this is a wonderful place to work. And the reason is for of great care we can offer patients.

And joining me today is Patrick Vargo, who's spent a lot of time with us. He is actually a native here from the Cleveland area. And he went to undergrad in Cincinnati and then here at Case Western for medical school, and then was a trainee with us. And he's turned out to be superb surgeon. And his interest is particularly in aortic surgery. So thank you for joining me, Patrick.

Patrick Vargo, MD:

Oh, thank you for inviting me to join you for this.

Lars Svensson, MD, PhD:

This is great. All right. So Patrick, let's start off with some questions for you. When do you decide to operate on a patient with an enlarged aorta?

Patrick Vargo, MD:

So when choosing to operate on a patient with an enlarged aorta, we look at the size of the aorta, the aneurysm specifically, or where the blood vessel is ballooned out. And we compare that to their size, as well as overall diameter. And the goal is really to try and estimate the risk of rupture and compare that to the risk of surgery.

Here we have very excellent outcomes and surgery is done very safely here. And so we tend to start to think about operating on the aorta when it's aneurysmal and around five and a half centimeters in the area of the ascending aorta, and slightly smaller in patients with connective tissue disorders or patients with family histories of aortic aneurysm dissections, closer to five centimeters.

Lars Svensson, MD, PhD:

Yes. So just to drill down on a couple of things, the guidelines recommend 5.5 centimeters if it's at an institution that is not a center of excellence, as it's called. So we tend to operate at about 5.2 centimeters in somebody who doesn't have any history of a connective tissue disorder, or it's a reoperation after previous operations. But in patients, as Patrick mentioned, with connective tissue disorders, we will operate earlier. And if a patient with Marfans has a family history of aortic dissection, from about 4.5 centimeters. And for patients with connective tissue disorder called Loeys-Dietz, also about 4.5 centimeters, because we know they have a greater risk of developing aortic dissection and rupture.

For bicuspid valves, it's usually about five centimeters for the aortic root, 5.2 centimeters for the ascending aorta. But we take into account what somebody's job is, what their height is, what their size is, if they have other evidence of a connective tissue disorder. And then we also look at the cross-sectional area versus the height ratio for patients.

So Patrick, you did a wonderful presentation on our 214 patients at the Western thoracic meeting. And do you want to talk about that study in patients with connective tissue disorders?

Patrick Vargo, MD:

Certainly. So we took a look at our patients that have connective tissue disorders and aortic root aneurysms. That's an aneurysm around the area of the aortic valve. And the treatment for that is to replace the aorta, and replace it with a cloth tube to eliminate the risk of rupture or tearing. But because it is associated with the aortic valve, a decision must be made about the aortic valve, do we replace it at the time of surgery or do we save it? And saving that aortic valve is a procedure called an aortic valve reimplantation, where the affected aorta is cut away from the valve. A cloth tube is sewn in in place of it, and the aortic valve is reimplanted into the cloth tube.

Patients with connective tissue disorders such as Marfans, Loeys-Dietz, Ehlers-Danlos, and some others were included in our study. And the question was, how durable is that aortic valve in these patients after it's been reimplanted into the aortic tube graft? And the outcomes were excellent. At around 12 years of follow up, greater than 93 percent of patients had a durable aortic valve that did not need to be replaced or intervened upon. That was excellent. And these patients did very well over the long term with this operation, which is very, very good because these patients do not need blood thinners. They do not have a mechanical valve. And those complications associated with blood thinners is no longer present in their life.

Lars Svensson, MD, PhD:

So as Patrick said, in that series of 214 patients, there were no deaths. And in the comparison group, there's only been one death in something like 1,200 patients, particularly in the patients with elective surgery. The last time we looked, the risk of death in elective surgery patients was 0.16, so very much, not quite one in 1,000, but certainly not much more than that. And very good results in that series. And as Patrick said, he quoted the 12-year outcomes. The other number that I usually use is 97 percent freedom from reoperation at 10 years for the connective tissue disorder patients, which are Marfans and Loeys-Dietz, as he mentioned, mostly in that. Really excellent outcomes for patients who otherwise would get a mechanical valve. And the problem of being on Coumadin. And then in the comparison group who didn't have a connective tissue disorder, also superb outcomes at about 93 percent freedom from reoperation.

So, this is a very useful operation in patients who have enlarged aortas in the root, and about 50 percent of those patients have some type of family history. And we now actually have a free genetic blood test that we have for patients who may have a connective tissue disorder. And what we're finding is, now as we do this complete analysis of patients who are coming in with these types of aneurysms. Often we will find there is a genetic mutation accounting for them developing these aneurysms of the aortic root. And that usually results in aortic valve leaking. And the earlier we can get to operate on those patients, the more likely we are to keep that aortic valve and restore a valve that is leaking to full competence. In other words, that they have their own valves for the rest of their lives.

All right, so Patrick, let's talk a bit about the aortic arch and the new trends in aortic arch surgery. And the frozen elephant trunks, the classic elephant trunks, and your thoughts about those two operations.

Patrick Vargo, MD:

Certainly. The aortic arch is the part of the aorta just beyond the ascending aorta. And it's the area of aorta that gives off the branches that go to the upper body, the arms into the brain. So surgery on the area of this aorta requires addressing those branches or reimplanting them or branching them. And then the procedure of the elephant trunk and the frozen elephant trunk speaks to inserting a graft that hangs down the very end of the arch into the descending aorta that runs along the spine. And this really sets up subsequent stages for repair of aneurysm that traveled beyond the arch and down the aorta.

So these procedures, I think the soft elephant trunk, traditional elephant trunk, it's a soft tube graft that we place down there and that we can access from the side. And then the frozen elephant trunk is actually a stent that we place down the descending aorta and we can do subsequent stenting into it. So the development of endovascular devices, stent graft devices has really continued to push what we can do with aortic arch repair. Placement of the frozen elephant trunk into the descending aorta allows us to, minimally invasive with stent grafts, come in from the groin, a very small nick in the groin, and extend that stent graft for aneurysms that descend that portion of the aorta.

Additionally, stent grafts have allowed us to use hybrid techniques in the aortic arch. So we're placing stents into some of the branch vessels in the arches to decrease time on the heart and lung machine, and give even more extensive repair in patients that may have not otherwise been able to tolerate that. And we're continuing to push the boundaries with stents that are deployed into the arch from the groin as well in different trials.

Lars Svensson, MD, PhD:

Good. All right. So Patrick, let's talk a bit about the descending and thoracoabdominal aneurysms, and your decision making on how you approach those patients with endovascular or open procedures.

Patrick Vargo, MD:

Certainly. So the descending and thoracoabdominal aorta, as mentioned, the aorta travels along the spine through the level of the diaphragm and into the abdomen where it gives off branches that go to the viscera, the kidneys, the intestines, the stomach, the liver until it reaches around the area of the belly button and branches go to either leg. Aneurysms that travel this length of the aorta, the thoracoabdominal aorta, often require very extensive repairs. Particularly when open, it's a large incision from the side to access the entire aorta.

Stent grafts have allowed us to treat many of these diseases without doing that. We can come in through the groin with a small incision and place a stent to the level of the diaphragm and treat aneurysms in the chest. And this often can treat these aneurysms entirely if the aorta tapers down to a normal size in the abdomen. In patients where it continues to grow in the abdomen, we can also do hybrid thoracoabdominal repairs where we then sew to those stents that we've placed into the chest to help minimize the extent of the surgery. This also helps patients recover a little bit faster with a smaller incision. And then the stenting of the abdominal aorta below the level of the kidneys can also be done if later repairs are needed at that level.

Lars Svensson, MD, PhD:

So one of the things we always fear with the open operations, and/or the stent grafts, is paralysis. Do you want to talk a bit about the approach to trying to reduce the risk of paralysis with these procedures?

Patrick Vargo, MD:

Certainly. As a part of descending aortic repairs, one of the dreaded complications, and it's been well documented - is spinal cord ischemia or poor blood flow to the spinal cord that results in paraplegia or paraparesis of the lower body. We've developed different strategies. With Dr. Svensson, one of the leading pioneers in this field, we’ve developed strategies to lower that risk.

So part of what we do to help prevent this complication is a spinal drain is placed operatively. It's a small needle placed catheter into the area of the spinal cord to decrease the pressure around the spinal cord during and after surgery so blood flow can get in easier. We also cool the patients during the surgery slightly to protect the spinal cord during the time of the operation. And we place these patients on the heart and lung machine during the operation, not to pump in place of the heart, but to pump along with the heart. To keep blood pressure going to the viscera, going to the body, and make its way through collateral to the spinal cord to lower this risk.

And finally, we like to administer a medicine into the spinal canal that dilates blood vessels called Papaverine, which has been shown to lower the incidence of paraplegia after these operations.

Lars Svensson, MD, PhD:

Yeah, great. So that is something that we really made a lot of advances on here at the Cleveland Clinic, is reducing the risk of paralysis of the descending and thoracoabdominal operations. And that was always a very feared complication, and the team has really made a lot of advances on that.

Anything else you want to talk about, Patrick, that excites you in aortic surgery?

Patrick Vargo, MD:

I think that the combination of using traditional open techniques, surgical tube grafts, aortic valve reimplantations, arch debranching, in combination with the rise of these new endovascular devices is really facilitating new approaches to treating aneurysms that are often hard to get to. The stents have, as mentioned, been able to treat a lot of these aneurysms minimally invasively. And when used in combination with open techniques, they can provide a definitive management with lesser morbidity and mortality to patients.

Also in the setting of dissections, aortic dissection, was where there's a tear through the length of the aorta, oftentimes after an initial repair to save a patient's life, these become a chronic medical problem that we manage and watch and intermittently have to intervene upon with surgery. One new area of treatment of these is using endovascular technology, again, stenting technology to access the dissections and stent the true lumen, stent the channel where blood is supposed to be and support it to hopefully prevent growth of the aneurysm. As well as access the aneurysm directly and place different types of devices to prevent blood flow into that area that pressurizes an aneurysm.

So the goal is really to treat these aneurysms with the least amount of mortality and morbidity. To get patients home faster and get them active faster again.

Lars Svensson, MD, PhD:

Yeah. That's an important point that Patrick touched on, and that's the treatment of the acute dissection. So here at the Cleveland Clinic we've actually had very good results with acute dissection repairs. The risk of death has varied between 5 percent and 7 percent or so. The national average, as measured by a study called IRAD, has run at 17 to 21 percent. And that's why we think there's a lot of virtue for a center of excellence to deal with aortic surgery emergencies. And we've done some studies that basically anybody who can get here pretty quickly with a helicopter, it's worthwhile getting transferred to the Cleveland Clinic to have emergency surgery for acute aortic dissection.

And the methods have evolved. We're beginning to see evidence that traditionally we've done what we call the hemi-arch. So we cut out the dissection and part of the aortic arch, and resuspended the aortic valve during these operations. A fairly quick operation, but also with the risk over time, as Patrick mentioned, that new aneurysms would form in the rest of the aorta. Now with the frozen elephant trunk, we're beginning to see evidence, even though it takes a bit longer to put in, that long term, the risk of developing aneurysms down the road is slightly less. There's often more interventions, but it results in a more complete treatment of the aortic dissections and less risk of open operations.

Blood pressure control is a very important part of the success or reduction of the risk of aneurysm formation. And in fact, one of the pioneers in this area, Michael DeBakey, showed that many, many years ago, some 40 years ago, that that was critical to the risk of developing aneurysms later. So for people with aortic dissection, the first operation obviously is very important to be done safely. Historically, we've always quoted the risk of death with aortic dissection as 40 percent, and that still holds true. And there's a reason study again showing the risk of death is about 1 percent per hour in patients until they get surgery.

And so this is a terrible complication of aneurysms. And that's why we have shown that if we operate on patients earlier with the reimplantation operation, the risk of aortic dissection is considerably reduced. We've actually shown that. And also, it's a very safe operation. And so for patients with aneurysms, we know we have good operations. If patients have aortic dissection, then it's a bit more complicated, but we're making progress in managing those patients.

So a lot of exciting things happening in aortic surgery. We have a lot more understanding of the disease, and we have some really great surgeons. Patrick's done a wonderful job and built up a very good practice, and big practice in aortic surgery here at the Cleveland Clinic. So thank you for joining us, Patrick. And thanks for chatting.

Patrick Vargo, MD:

Thank you.

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