Talking Tall Rounds®: Aortic Valve and Root Surgery

Podcast Transcript

Announcer:
Welcome to the Talking Tall Rounds series brought to you by the Sydell and Arnold Miller Family Heart, Vascular, and Thoracic Institute at Cleveland Clinic.

L. Leonardo Rodriguez, MD:
Good morning. Welcome to the Heart, Vascular, and Thoracic Institute Tall Rounds. This is a very interesting topic and very challenging, of patient with aortic valve and root surgery, particularly when they're young. We have a very solid panel today to discuss these issues and cover multiple aspects. We're going to start with Dr. Joshua Cohen, one of our fellows, and he's going to present one case to illustrate the issue. I'm part of the imaging section, I'm not a pathologist, that goes to my harmonimous, Dr. Rene Rodriguez, we're going to deal with the topic of pathology and if we should operate these patients early, as was mentioned in the prior case.

L. Leonardo Rodriguez, MD:
So as you know, and the case just presented, this pathology can be seen in young adults and also children and it is often caused by either hereditary or genetic conditions, this is a short list of that, Marfan syndrome, bicuspid aortic valve probably constitute the bulk of the practice of adult cardiologist dealing with aortic root pathology and associated valvular heart disease, but the list is fairly long and has a specific features in each of them. In some cases, the aortic root is an isolated finding, but in many, it's associated with valvular heart disease, in young adults the is primarily regurgitation, and in the cases of bicuspid valve, the mechanism is prolapse often, but also could be present thickening, deformity, and restriction of these leaflets, making the repair much more difficult.

L. Leonardo Rodriguez, MD:
If the patient has aortic root dilatation and tri-leaflet valve, the usual mechanism of the vavular lesion is, again, regurgitation, mostly due to dilatation of the aortic annulus, sinotubular junction, and the heart root itself, pulling apart the leaflets and causing most of the time central, often severe aortic insufficiency.

L. Leonardo Rodriguez, MD:
I don't want you to memorize all this, but this is some of the genes, so most of the genes, that has been associated with aortopathies. This is obviously one of the most common, discovered as a cause of the vascular problems in Marfan patients, this gene is associated with fibrillin 1 problems, but also the pathways of the transforming growth factor beta, present in Loeys-Dietz syndrome, but also in patients with bicuspid aortic valve, some will have associated abnormalities in this particular gene. These genes are involved at different levels. This is in the extracellular matrix protein, but also the transmembrane protein. And again, the list continues, a very long ... ACTA2 is also another gene that has been associated with nonsyndromic aortic aneurysm. But also pay attention that in patient, for instance, like Loeys-Dietz or also Ehlers-Danlos, there are multiple genes that have been associated with this pathology and then, again, causing multiple abnormalities.

L. Leonardo Rodriguez, MD:
I'm not going to go into detail again, this is the realm of pathologists, but even though this gene has been clearly identified, the final pathway that causes aortic pathology and also the systemic feature, is not that well understood and involve, again, multiple pathways, importantly, again, the TGF-beta and also other pathways like the fibrillin abnormalities. Despite all the research that is done, what the specific role of TGF-beta remains controversial, and an old paper mention if this is protective, it's actually harmful, or indifferent. So this is a lot of research and the understanding of the final expression of this gene is a matter of active research.

L. Leonardo Rodriguez, MD:
It's important to us, to see this group of patients in two categories. One, is what it called syndromic patients, when they have associated systemic abnormalities. Again, the classic example is the Marfan syndrome that in addition to the aortic pathology, have mitral valve abnormalities and also skeletal abnormalities also present in the Loeys-Dietz and Turner syndrome. The nonsyndromic are those familial forms aortopathy, but without systemic features, bicuspid valve is one of them, and the familial thoracic aneurysm and dissection should be another cause of isolated or mostly limited to vascular problems and no systemic issues.

L. Leonardo Rodriguez, MD:
Again, I'm not a pathologist, so Dr. Rene Rodriguez usually shows spectacular pictures. I'm going to go for cartoons, but this is the usual composition of the wall of the aorta: the intima layers usually single cells that communicate what is going in the blood environments to the rest of the wall; the media, which is important as the architectural backbone and provide all the mechanical properties of the aorta, is composed of elastic fibers, collagen, also smooth muscle cells; and the adventitium.

L. Leonardo Rodriguez, MD:
The main finding in common on these patients is medial degeneration, the specific composition and how these different abnormalities vary among these patients, but in general, all of these patient will have profound abnormalities in this medial layer. The old terms has been changed, and this is the new nomenclature, come from the consensus where Rene Rodriguez and Carmela Tan were part of this. And again, the old names of cystic medial degeneration has been tried to change to more descriptive, but in general, this mucoid extracellular matrix accumulation, the abnormalities and collapse of elastic fibers, apoptosis of the smooth cells, and again, in general, abnormalities in this area. The laminal unit, which is the fundamental composition of the aortic wall, is abnormal, not only in patient with Marfan syndrome and Loeys-Dietz, but also in bicuspid aortic valve, again, when there is destruction or alteration of these layers. This is an example of what was used to be called cystic medial necrosis, and this at this pool of proteins here, it may alter the laminal structure of the aortic wall.

L. Leonardo Rodriguez, MD:
Now, do we operate, or should we operate early in young patients as opposed to follow the natural history in these patients? So I think for clinicians and imagers, when we think about the timing of intervention, we look at what is the primary lesion? Is that the aneurysm of the valvular lesion with aortic insufficiency or stenosis? Do we think that this patient has an increased risk of dissection or rupture? And we look at the specific syndromic features that may increase the risk, also, if there is family history of aortic rupture. And finally, obviously important for the decision, can we keep the native valve of the patient over alternatives for long-term survival, free of events. And again, favoring early surgery is the fact that we want to prevent this cumulative risk of the dissection, that varies according to the pathology, and also prevent permanent damage for negative remodeling, LV dysfunction in patient with severe aortic insufficiency or stenosis.

L. Leonardo Rodriguez, MD:
And favoring delayed surgery, of course, is the intrinsic surgical risk. This is a population that are young and in general the risk is not very high, and in big center, like ours, is actually very low. And of course, if you have to replace the valve, is to the long-term durability and anticoagulation issues of this valve, and this balance help us to decide what is the best timing for this surgery. Again, in terms of when to decide, you can see here that these patients present relatively young with dissection, and therefore, we want to avoid exposing to this patient. And the incidence dissection varies widely. You can see here at the bottom that the aortic bicuspid valve is 0.2%, which seems low, but remember there are thousands of patients with bicuspid valve, so the absolute number of patient presenting with by bicuspid valve and dissection is actually high given the incidence of data.

L. Leonardo Rodriguez, MD:
And again, what are the criteria for intervention in these patient varies according to the society that you looked at, but in general, tends to be a little bit lower compared to degenerative valvular aortopathies. So again, there is a tendency to deal with that in these patients early.

L. Leonardo Rodriguez, MD:
Now, if you can spare the valve, this is a topic that Dr. Svensson is going to deal with. This great because the durability is excellent or other alternative like the Ross procedure, Dr. Phillips is going to address that in great detail and help us, again, to choose the right therapy for this patient.

Lars Svensson, MD, PhD:
My privilege to talk a bit about the reimplantation, connective tissue disorders, and bicuspid valves, and give you a overview of what we'd been doing. So in 2019, we did 1,300 odd aortic operations, and in 2020, it increased to 1,381, which is one of the rare areas where we saw growth last year. And we did do less reimplantations, however, last year, so we went down to 112, but as of December last year, we had done 1,113 reimplantations with a mortality rate for elective surgery of 0.12%. Just to give you an overview also, where we stand in the last decade of cardiac valve surgery, in particular, isolated aortic valve 0.3% mortality rate, and for TAVR a 0.6% mortality rate, about equal numbers there in total, but we've also done 4,680 aortic valve repairs and that's what I'm going to concentrate on.

Lars Svensson, MD, PhD:
Debbie and Leonardo had touched a bit on when to operate, so the impetus for this was that we found 15% of patients dissected less than five centimeters with Marfan's in a study we did many years ago, and we came up with this ratio, the cross section area to height of 10, as indication for surgery in Marfan's and also bicuspid valves. What that means is a shorter person gets operated at a smaller size, and here's the relationship of height and size of the diameter and dissection, and here's with the ratio. So that takes out the effect of height on the risk of dissection.

Lars Svensson, MD, PhD:
So as was mentioned, Milind Desai, did this study looking at patients with a ratio greater than 10, they had a worse long-term survival, and it was even worse if it was the aortic root where it was enlarged versus ascending aorta, which is also in keeping with our bicuspid valve data. So this is a study of 1,181 bicuspid valves with a aorta above 4.7 centimeters that we followed, and the ratio was the best indicator when to operate. So here's just in diameter terms, at about five centimeters the risk of aortic dissection starts increasing for the root, and for the ascending aorta, somewhere around 5.2, 5.3 centimeters. Also, to remind you that you can have dissections and tears that cannot be picked up on usual imaging, and here's a localized tear right next to the left main in a patient who had classic symptoms of aortic dissection and was initially missed. Incidentally, we've repaired the bicuspid valve with figure-of-eight sutures.

Lars Svensson, MD, PhD:
So why repair? Well, the incidents of event-free survival at 10 years is about 50% with the St Jude's prosthesis. Doug covered the new On-X valve, which we think has a lot of promise, and that's why we're randomizing patients in the study against Eliquis. If you look at pericardial valves, there's no difference over allografts, with a higher failure rate in young people. So that's the reason here, in powder blue, why younger people, we particularly try and repair the valves.

Lars Svensson, MD, PhD:
So how do we do it? The key to doing a successful aortic valve repair is looking at all these factors, and so we rely very much on our imaging colleagues to tell us about this. So the keys are the commissures, leaflets, annulus, sinuses, and sinotubular junction to the result in a successful repair. So let me run through some of this. This is a bicuspid valve with a figure-of-eight stitch. So originally I did a series of patients where I freed up the commissures and put them at a higher level in the ascending tube graft, and as far as I know, none of these patients have required a reoperation. But it was a operation that was a bit more complicated, so we started looking at a figure-of-eight suture at the leading edge of the commissures, apart from the Cabrol sutures, with the pledgets to hitch up the leaflets, and there's just the diagrammatic view, and we use clips so that the Gore-Tex sutures don't come loose.

Lars Svensson, MD, PhD:
So here's a patient with a plication and a Cabrol suture, and then the figure-of-eight sutures hitching up the leaflets, and you see, they come up to higher level. Here's a patient with reefing of the edge of the bicuspid valve. And here's a patient with bicuspid valve with those repair techniques, and we're going to do a root remodeling operation where we cut a bevel into the ascending tube graft, and then reattach that to the annulus. Here's another patient with reefing, figure-of-eights, and Cabrol sutures, and we use a Hagar's to make sure we don't cause aortic valve stenosis at the end of the operation. And this was a patient, there you see nice symmetrical valves, and there's a remodeling operation in this particular patient. Our data shows that the more recent patients have better durability. Obviously we don't have 15 year follow up in the most recent patients, but it looks like we've improved things before bicuspid valves.

Lars Svensson, MD, PhD:
Here's the tailoring operation where we repair a three leaflet valve, and you see the figure-of-eight sutures there, and then separately put in a tube graft above the repair at the sinotubular junction and we bring down the size of the sinotubular junction. What about reimplantation and the techniques we use for that? A critical part is making sure that the entire valve is freed up, so it sits within the tube graft with the replacement. So here's a technique I started using, modification of the Tirone David operation that I started using in the 1990s with pledgets in the left ventricular outflow tract, and there you see the intraoperative picture. And then reducing the size of the annulus down to the patient's body surface area with a Hagar's for tying down the pledgeted sutures. Here's also figure-of-eight suture with a nice symmetrical valve, and we aim to get about three to five millimeters of apposition to improve long-term durability of these repairs.

Lars Svensson, MD, PhD:
So here's an example of a patient a couple of weeks ago, and you see there's some prolapse of the left right leaflets, and so we're putting in sutures here of figure-of-eights. I'm doing this watching the TV screen because my camera was off focus, and we are just putting that in there, and we're going to put that figure-of-eight at the commissure, and then we're going to hitch this up to a higher level, about three to four millimeters higher, and you'll see how this pulls up the apposition level to a higher point and creates just a better apposition of the leaflet. So there you see that, put a clip on that, and then we'll put some ... Look at that, and you see this nice apposition, nice symmetrical valve.

Lars Svensson, MD, PhD:
So a lot of these patients have Barlow's valves. I had a patient last week, severe mitral valve regurgitation and aortic valve regurgitation, root aneurysm, probably Marfan's, but not diagnosed. And these valves can be complicated to repair and multiple techniques are used for these, in this case, chordal transfers and artificial chordae, and also the Cosgrove band.

Lars Svensson, MD, PhD:
So as of about a year ago, we had done 64 patients combined mitral valve repair and reimplantation, and there've be no failures in that group of patients. And the patient I did the other day has no leak from the mitral valve, trace from the aortic valve, and is going home probably today.

Lars Svensson, MD, PhD:
So what about follow up on these patients? Survival is not as good in the tailoring patients because it's an operation we use in older patients. Repair durability, well we've had a couple of failures, not many with the reimplantation technique. This is a patient with Marfan's and they obviously have myxomatous valves, and the leaflet's stretched over time. So this is one of our rare failures over time. So if you look at reoperation risks, they're about the same for those three techniques, but bicuspid valves have a higher risk of reoperation and that's shown in this slide.

Lars Svensson, MD, PhD:
So what about connective tissue disorder patients in young patients? We did a study 10 years ago of 178 patients with connective tissue disorders. Here's the breakdown of the types, Marfan's predominating, but Loeys-Dietz, Ehlers-Danlos, and others included. There were no deaths in that series of patients. What about effectiveness? So reoperation risk was 92% at six years, and this was in our early period of doing these patients and that's become better. So as of December 2020, we've done 214 patients and still no deaths for connective tissue disorder patients. And the preliminary data looks like we're going to be somewhere in the region of a 97% freedom from reoperation now at 10 years.

Lars Svensson, MD, PhD:
What about long-term durability of all aortic valve repairs? So a few years we looked at this, including various techniques of bracing the aortic root, as I've described already. We used various leaflet repair techniques, listed here. So in the more recent patients, just over a thousand patients, freedom from reoperation, so this is all comers, four plus AI, for example, with no root, there was 90% at 10 years after surgery. In the patients that we used a figure-of-eight stitch, that durability was better, and the patients where we did root procedures, the results were also better, in other words, where we braced the aortic valve. And the matching to the age population was also excellent.

Lars Svensson, MD, PhD:
More recently, we also compared reimplantation versus Bentall's, and less than 70 years, the mortality risk for reimplantation was 0.16 versus Bentall 0.22. And the freedom from reoperation and the reimplantations was 97% at 10 years. So thank you for your attention.

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