Ask the Heart Doctor: Aorta Disease Part 2

Podcast Transcript

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Lars Svensson, MD, PhD:
Hello again and I'm Lars Svensson, chairman of the Heart and Vascular and Thoracic Institute, and with me today are Sagar Kalahasti and Milind Desai, experts in aortic diseases.  We love talking about aortic disease and we have a very big program here at the Cleveland Clinic. Last year, we actually did, despite COVID, 1,381 aortic operations. So by far the biggest in the world, and we have a very active program and we see a lot of emergencies, urgent patients needing surgery, and also elective operations. In fact, as of December last year, we had done 1,113 modified reimplantations of the aortic valve. And I was just looking at data this morning with 214 patients with connective tissue disorders, we have not had a death after that operation, and there is no significant difference in our hands as far as the durability of these reimplantation, operations, and preserving the aortic valve between connective tissue disorders and non connective tissue disorders.

Lars Svensson, MD, PhD:
That's hot off the press. I saw it this morning and that's in 214 patients, so really good results. For the general population without connective tissue disorders, we're also running at 97% freedom from reoperation, 10 years after surgery, and for elective surgery operations, we've only had one death out of 860, so about a 0.1%, one in a thousand risk of death, for a very complicated operation that only a few of us do in the country. So we're going to start off by talking about what size should you operate on a patient and do the symptoms make any influence on this? What about body size? Does it make a difference for aortic root bicuspid valves, age, family history, or family history of aortic dissection? I'll start off with you and Milind, and a lot of issues in that decision-making.

Milind Desai, MD:
This is a very interesting question, and the answer is not a one size fits all answer. The first and foremost thing I'm going to say and emphasize as Dr. Svensson mentioned, experience is key, having the right team of folks taking care of you is probably more important than anything else, especially more important than any other disease, the synchrony of how the teams operate. So having said that, the thresholds are... Yes, there is nuance decision-making about thresholds. Most people are going to be hearing numbers, five centimeters or higher, five and a half centimeters or higher, these are fairly common numbers in terms of thresholds you're going to be hearing. But there's substantial nuance decision-making and thought process behind how we send patients for an operation. Clearly you are reaching 5.5 centimeters, that's a no-brainer.

Milind Desai, MD:
But what about, if you are somebody who's barely five foot tall and your aorta is 4.8 centimeters in the ascending portion, do we have the same threshold versus somebody who is six foot one? The answer is clearly no. So very often, precision of measurement is crucial and once we are precise in measurement, we often index your aortic area to your height. And we have multiple publications that have shown that, that adds incremental value beyond just simple dimension measurements. So a ratio, if you're aortic area to height ratio happens to be more than 10, then data have shown, large scale data have shown that you are better off getting operated at an experienced center with such stellar outcomes, preemptively, before your aorta reaches five or five and a half centimeters.

Milind Desai, MD:
The other important group is those with familial predisposition, especially those with Marfans or those with Ehlers-Danlos or any familial diseases, Loeys-Dietz syndrome, the threshold needs to be much lower than five centimeters, and it often is if you have a malignant family history of multiple family members dying of a dissection. Then we are going to not wait for the standard threshold, we would recommend getting operated earlier.

Milind Desai, MD:
The other group is patients with valve disease who need to have a heart surgical operation, then the threshold that we use is 4.5 centimeters. So if you are undergoing aortic valve surgery or mitral valve surgery, if you're ascending aorta is more than four and a half centimeters, then we would recommend getting the aorta replaced at the time of that operation. So it is not one size fits all, there is nuanced thought processes, your height related, malignancy of your family related, whether or not you need concomitant history, and also at an experienced center like ours, we are more inclined to initiate the operation conversation once you reach at a five centimeter threshold. There are plenty of patients who have careers that are not conducive to walking around with a significantly aneurysmal aorta. So in those patients, we would recommend an earlier operation, especially if done by an experienced center, by an experienced surgeon.

Lars Svensson, MD, PhD:
So Sagar, would you like to add to that and particular in relation to age, the size of aortic root versus the ascending aorta and patients with bicuspid valves?

Sagar Kalahasti, MD:
Thanks Dr. Svensson. In bicuspid valve patients, again, there are certain phenotypes, particularly with the aortic root being involved or aortic root being aneurysmal. I think data has shown that operating that smaller sizes, particularly in conjunction if they have aortic valve regurgitation, definitely makes a significant amount of difference for those patients. In other conditions, such as in Marfans or Loeys-Dietz, of course we would operate at much smaller sizes, more into the four to 4.3 centimeter range. And in Mafans again, I think the thresholds will continue to come down. I think current recommendations would say about five centimeters, but probably less than that, if there is any family history of dissection or smaller sizes in those family members. So I think that's important to keep in mind.

Lars Svensson, MD, PhD:
So we looked at just over 1,100 of our patients with bicuspid valves and an aorta more than 4.7 centimeters in size, and we found that the risk of aortic dissection increases at about five centimeters diameter for the aortic root and for the ascending aorta about 5.2. But we found the best predictor of dissection occurring was the ratio. In other words, Milind mentioned a cross sectional area divided by the patient's height in meters when that was above 10. And the other important point is, when we follow these patients out to 10 years, the bigger the size they started off with, the more likely they were eventually to need an operation, so that also comes into our thinking.

Lars Svensson, MD, PhD:
We also consider what's happening with the bicuspid valve. Is it a valve that's diseased? Is it a valve that maybe will last a few more years and we can use a biological valve and that at the time of surgery and the replacement? So that also comes in to our thinking. So in 2010, I was involved in writing the Thoracic Aorta Guidelines sponsored by the American Heart Association and American College of Cardiology and Surgical Societies. And we recommended surgery at about five centimeters for most patients with bicuspid valves and Marfan syndrome, but also using the ratio, older patients who don't have any risk factors and ascending aorta certainly a larger size, can be watched.

Lars Svensson, MD, PhD:
Then at later, the valve guidelines came out and recommended 5.5 centimeters, which resulted in a lot of confusion. And the two groups then got together, and at that stage, we had published our series on bicuspid valves and the recommendations then came out that were modified and that are in the latest valve guidelines now also. So the cutoff is five centimeters in diameter, particularly if their root is involved and the operation can be done at a center of excellence, then it's reasonable to operate, and that's more or less what we use.

Lars Svensson, MD, PhD:
If there're other risk factors, particularly family history of aortic dissection, then we operate at a smaller size. Now this is in a sense of prophylactic operation, we do before aortic dissection happens, because if an aortic dissection happens, then that usually results, first of all, in a very high mortality rate. With a dissection there's new research confirming again, that the risk of death is 1% per hour in patients who have aortic dissection, if they don't die immediately and they're awaiting surgery. And then on top of that, if they have a successful operation and the mortality rate for an operation for acute dissection varies from round about 5 to 6% here at the Cleveland Clinic, but in the IRAD database, that used to be up to 21%. And then if people get through that, they have typically multiple operations after that. So it's very important to have the prophylactic operation if the aortas enlarge.

Lars Svensson, MD, PhD:
So the obvious question is, well, does it prevent aortic dissection? So we looked at some 660 of our patients that had roots surgery, not all of them reimplantations and the risk of developing a later dissection, typically in the descending aorta, so area not operated on was 1.4% and the most important risk factor for that was Marfan syndrome. So it does reduce the risk of subsequent dissection and in patients who don't have a connective tissue disorder, they can go back to completely normal lifestyle. And even in the Marfan syndrome, or Ehlers-Danlos patients, or Loeys-Dietz patients, depending on what the activity they're planning to do, they can live a normal lifestyle. And in fact, our data shows a normal life expectancy in those patients once they've undergone their operations.

Lars Svensson, MD, PhD:
So there are some surgical operation questions. So I'm going to ask onto those directly, so what is surgery and what is available for the ascending aorta? So if it's only the ascending aorta and not involving the aortic valve, we will typically do what we call a minimal invasive J-incision. And so that's an incision about three centimeters long in the upper chest, and we make it so like a trapdoor, we go in and we put in a plastic tube, it's actually a polyester, it used to be called Dacron, and we replace the aorta with that, we sew into position and we know that the results of that are very good.

Lars Svensson, MD, PhD:
In fact, if you look at our patients with bicuspid valves who had aortic replacements, the risk of another aortic operation within 15 years of the original operation, it's only 2%. That's separate from the aortic valve, the aortic valve as a separate issue. So what if the aortic valve bicuspid valve is involved? Well, then it depends what the problem is with a bicuspid valve, and just to segue a bit to my cardiology colleagues here, in a bicuspid valve, when do you operate for a valve that's narrowed down. I'll ask that of Milind and for a leaking valve, I'll ask Sagar to answer that question. Milind, a stenotic valve.
Milind Desai, MD:
As Dr. Svensson mentioned, a bicuspid aortic valve, it is where essentially there are two leaflets, two flappers rather than three, and this tends to be an inherited situation. So there's two... Typically what the natural history of a bicuspid aortic valve is, it progressively gets calcified or calcium buildup happens, and when patients reach typically in the late fifties, early sixties, it gets severely narrowed to a point where it then is impeding the flow of blood out of the heart, which essentially results in symptoms. Symptoms often involve shortness of breath, chest pain, dizziness, occasionally passing out, and if you leave it untreated, then it results in a heart failure like symptoms. So once the aortic valve gets narrowed to a severe level, so there's cutoffs, there's thresholds, there's severity, it could be an absolute number of less than one centimeter square or 0.7 centimeter square would be critical. You can index it to height, given the discrepancies in various heights. You can index it to height, either way, once it reaches severe in terms of valve area.

Milind Desai, MD:
There's another way of ascertaining severities through gradient. Gradient is the pressure difference between the aorta and the heart, because of a severely narrowed aortic valve. Once these thresholds reach beyond severe it's typically when we start thinking about an operation, especially in the context of symptoms. There's emerging data now that waiting for symptoms may be waiting a bit too long, so we are developing new biomarkers like blood tests, like BNP, strain values, et cetera. These things can help guide decision-making about timing of an operation, but once it clearly reaches severe, in terms of narrowing, it's the time for you to operate. Now, there may be certain scenarios where we may operate in a moderately narrowed valve. If the patient is undergoing surgery for other reasons, like bypass or mitral valve disease or something else, then we may operate, replace that aortic valve, even if it is moderately narrowed. But generally, we wait for severe valve disease, severe stenosis, severe narrowing of the aortic valve before aorta pairing or replacing.

Lars Svensson, MD, PhD:
Sagar, what about a regurgitant valve, leaking valve?

Sagar Kalahasti, MD:
Thanks Dr. Svensson. Just like Milind had mentioned, aortic valve regurgitation also, there are parameters with regards to looking at the severity of the valve regurgitation dealing with mild, moderate, and severe, and if the valve reaches severe range then in general, aortic valve intervention is recommended. Now keep in mind with aortic valve regurgitation, there's a lot of leaking across the valve and that leak is going back into the ventricle. So over time, the ventricle has to enlarge or dilate to accommodate all the blood that's leaking back. And as Milind has mentioned, sometimes even before patients develop symptoms, symptoms can be very vague in different patients. Sometimes it can just be tiredness, or shortness of breath, or sometimes advanced stages, you could actually get swelling of your legs, like with heart failure. So there is more impetus now to prevent the ventricle reaching the point of becoming dysfunctional, and echocardiogram is very helpful in looking at the size of the ventricle and sometimes intervening before the ventricle reaches dysfunction.

Sagar Kalahasti, MD:
In the setting of aortic valve regurgitation, I think it's a very good idea. Just like Milind mentioned, if you're undergoing surgery for aortic, if the aorta is enlarged and you're going to fix the aorta, then I think addressing the aortic valve regurgitation is also important. Some of the caveats or differences with the stenosis is that, aortic valves which are leaking, can actually be repaired, and Dr. Svensson has excellent experience in looking at the aortic valve repair as an option, instead of replacement and that's another important factor to look in, in the aortic valve regurgitation.

Lars Svensson, MD, PhD:
All right. Another surgical question is, when is the reimplantation operation appropriate? So we do this operation when the valve is not calcified and the aortic root is enlarged, and we do that for both bicuspid and a three leaflet valves, the normal valves. We reimplant those within a plastic tube, that's why it's called a reimplantation operation. And as I mentioned earlier, the results are really excellent with that operation. The way we've modified it, it's very predictable, really excellent outcomes long-term. And so when it comes to the reimplantation operation, if there's not much aortic valve regurgitation, like two patients I saw today, I will tell them the likelihood is 95%, we can reimplant that valve in a new tube and keep their own valves. If there's severe regurgitation, the regional three or 4%, a three and four rating, so that's out of a score four, and the valve is a three leaflet valve, then it goes down to somewhere in the region of 85, 90%, we can keep the valve, and that's dependent of the big holes and the leaflets or not.

Lars Svensson, MD, PhD:
For bicuspid valves, we have also the option of a remodeling operation or a direct repair of the bicuspid valve and replacing the ascending aorta, which has also very good operation. We've actually looked recently at whether it makes a difference, replacing the ascending aorta at the same time with a bicuspid valve repair or only doing a repair, and the results are about equivalent for bicuspid valves. And when there's a root involvement, we've got what's called a remodeling operation or the reimplantation operation, depending on the situation that we find. So those are the operations.

Lars Svensson, MD, PhD:
Do we do minimally invasive operations for the root operations? So I developed the J-incision in the mid nineties and I pushed it to the limits. We were doing the so-called arch elephant trunk procedures with that, I did a lot of reimplantations, root remodelings with that. But I must admit, I've backed off on that because these are already complicated operations, and it's very helpful to have a good view of the heart, to make sure the heart is well-protected during these operations. So I don't any longer do reimplantations as a minimally invasive operation for those reasons, I think we can get a better long-term result with a full sternotomy as we call it.

Lars Svensson, MD, PhD:
So there are questions about FDA approval for the peers devices and various types of braces for aortic valve repairs. So we've actually got a series of some 4,600 aortic valve repairs, not necessarily with aneurysms, although when we brace the root, we have better results. And we feel the results are so good, and any of these devices introduce more complexity and potential problems. And for example, with wrapping the aorta, for example in Marfans, what we see is when patients have had that done, it's a bit like a balloon. And as a child, if you took a balloon and squeezed it, what happened? The other two ends popped out, and that's what happens when people put wraps around the aorta, other parts starts growing.

Lars Svensson, MD, PhD:
So the operations are so safe nowadays, and there's no reason to do wraps and so on when we can do a much more effective operation with better long-term durability. So for our ascending aortic replacements in patients with bicuspid valves, the risk of death was 0.25%, quarter of a percent. And we know, as I mentioned earlier, that that's a very durable operation and so we have not tried using these other devices, which can cause scarring and other problems over time.

Lars Svensson, MD, PhD:
So I'm just going to touch on a couple of other topics, which is endovascular treatment of the ascending aorta. That is a experimental procedure that can be sometimes used in very high risk patients when their localized tears or dissection of the ascending aorta, particularly in elderly patients, when other options aren't available, we are investigating that. But at this stage, that is not a treatment that we would recommend as an alternative for any of the very safe procedures we do.

Lars Svensson, MD, PhD:
What about patients with aortic enlargement who need TAVR? We would not recommend a TAVR, anybody who's aorta is more than 4.5 centimeters just as we do with surgery, because there's a very high risk of aortic dissection with TAVR, an enlarged aorta. What about, does all ascending aortic aneurysms require open surgery? I think I've answered that from the point of view of endovascular and yes, for 99% of patients, the ascending aorta replacement during an open operation, particularly if it's appropriate, min invasive operation is a very safe operation. So how long does aortic surgery last? In the bicuspid valves, as I said, there's a 2% risk of another operation within 15 years. In patients who have giant cell arteritis, there is a slightly higher risk over time, so we tend to do more extensive repairs in the patients with giant cell arteritis.

Lars Svensson, MD, PhD:
So many inpatients with aortic dissection, we are tending to become more aggressive in the operation and particular replacing the ascending aorta and arch, even with stent grafts, so that a second operation through the left chest or with a stent is easier to do. We talked about the modified reimplantation David Procedure, and as I said, we have about a three in a 100 failure rate at 10 years, my guess is, it's going to be about a five, 6% at 20 years. The results are really looking good with the way we've modified the operation and narrowing down the left ventricular outflow tract with a Hegar's dilator that's normal for the patient's size and height.

Lars Svensson, MD, PhD:
How about biologic valves? Biologic valves durability is very dependent on the age of the person. The way we've looked at it, and you can look it up in the literature is, we've looked at the risk, our reoperation within 12 years of surgery. So the younger the person is, the greater the risk. On the other hand, in the elderly, the biological valves hold up very well. And there's always an option of doing a TAVR in those valves over time. Having said that, in patients who have aortic valve replacement at the Cleveland Clinic, there is no difference in the risk of death for a first time operation, or a second or third operation, what we call a reoperation, and that's been the case since 2010.

Lars Svensson, MD, PhD:
So at the Cleveland Clinic, there is no difference in risk between those operations. We talked about life expectancy, but just to reiterate, inpatients who have prophylactic operations and who have aneurysms replaced before aortic dissection, the life expectancy is normal and we've got several studies that have shown that, including with a valve replacement, where the aortic dissection, then it's very dependent on the blood pressure control after the procedure. All right, so there are a couple of other question, how often is a pacemaker needed after valve surgery? I'll start off Sagar with you, what about pacemakers after aortic surgery?

Sagar Kalahasti, MD:
So in general, for most patients with aortic valve replacement, they wouldn't need a pacemaker, unless they have a prior conduction abnormality within their rhythm, something like a left bundle branch block or a right bundle branch block. if they have that going into surgery, then a very small number of patients may require a pacemaker after aortic valve replacement surgery. But in general, for most patients, pacemaker is usually not necessary.

Lars Svensson, MD, PhD:
So usually we quote about a 1 or 2% risk of a pacemaker with a open aortic valve replacement. It runs at about eight to 10% for TAVR, although our team has had better results than that. For a reimplantation operation, we usually run at about 2 to 3% risk of a pacemaker after that type of operation. So let me turn to you Milind, as we wind things down here. What medications do you like to put patients on after aorta surgery or valve surgery and how often would you monitor patients, whether that's with the MRI, CAT scans or Echos, what are your thoughts on that?

Milind Desai, MD:
Thank you so much. So in terms of post operative medications, we have a preferential bias towards keeping patients on beta blockers, because a lot of these patients have concomitant cardiovascular disease, LVH et cetera, and it helps with the blood pressure, it helps with the heart rate, it helps with postoperative AFIB, et cetera. So it is something that we would typically continue these patients on, at least in a low dose. Now, a lot of other post operative medications would be driven by what other concomitant conditions they have, especially if they have cholesterol problems. If they have hypertension that requires multiple medical therapies, then the bias would be for the angiotensin receptor family of drugs. Now, in terms of follow up, there is... Clearly depending upon the extent of the disease that the patient had, and the extent of the disease that the patient had fixed, is what is going to drive the follow up regimen.

Milind Desai, MD:
So for example, if you have somebody with a dissection, that extends from the ascending aorta all the way to the groin, and we have fixed the first part of the disease by open-heart surgery, these patients will have a different and a lot more regimented, much more frequent follow-up schemata than somebody who just had a small area of ascending aorta that needed replacement and everything else is normal.

Milind Desai, MD:
Now, having said that, it is important for... An aortic patient, is a lifelong patient. Aorta is a lifelong disease, so even if we have fixed you, ostensibly fixed you, you need to follow up. We like to see patients at least once a year and do their imaging. Now, if the valve is involved, then you need to also image their valves using echocardiography and/or occasionally MRI. If it's the aorta, then a tomographic scan is important. If it is a dissected aorta, that has had stents placed, then you need a special type of CAT scan to look for what is called endoleak. So it is again, not a one size fits all. The most important message that I would say is, you are a lifelong patient and every care is individualized and should be discussed with your expert provider.

Lars Svensson, MD, PhD:
So Sagar one last question for you. What do you do for patients who have occasional loss of vision who have had a aortic operation, and this I think is particularly relevant to mechanical valves, what do you do for those patients?
Sagar Kalahasti, MD:
Thank Dr. Svensson. I think anti-inflammatory medications like aspirin, is routinely used in patients with both valve replacements, I'm talking more biological valve replacements or valve repairs. And of course for mechanical valve patients, you need to be on blood thinners, particularly Coumadin is the only one that's currently approved. So if somebody has a loss of vision, despite being on these medications, I think it's important that they're evaluated by neurology to make sure there is no other reasons, but I think being on aspirin is the important thing for patients with biological valves, or with the valve repairs.

Lars Svensson, MD, PhD:
All right. Just a couple of final points. One question was, how often do patients who've had modified reimplantation developing leaking valves? As I've said before, the risk of reoperation is about 3% within 10 years of surgery. I happened to be looking at some of our data on echocardiograms today. So about 30% of patients who have one plus or less, which is our standard for leaving the operating room after reimplantation operation, about 30% will develop a slight valve leak over time. Usually that occurs in the first year or two, but then after that it's stable over time, doesn't seem to get worse. So about 30% will have one or two plus regurgitation. Now, if it progresses, then there is the risk of reoperation, which turns out to being pretty rare in our series of patients. In fact, the one series I was looking at today, 22 patients needed another operation for just under 1000 patients, and six of those were patients who had Marfan syndrome.

Lars Svensson, MD, PhD:
But as I said, we found no difference between patients who had Marfan syndrome, and those who did not have Marfan syndrome, that is somewhat influenced, that in patients with bicuspid valves who have reimplantation, they are more prone over time to get calcification of those valves, because they are abnormal or leakage of those valves, so that does influence the outcomes. We know that long-term bicuspid valves do have a slightly higher rate of failure. In our experience, when we looked at 728 patients, the risk was 9%. So in other words would recall freedom from reoperation at 10 years was 91%. So the results are very good with repairs in this group of patients. I hope you've found this useful, it's been a long session, but we've tried to cover all your questions and group them together. Thank you very much, and it was a pleasure speaking to you.

Milind Desai, MD:
Thank you.

Sagar Kalahasti, MD:
Thank you so much for the opportunity.

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