Important Anatomic and Physiologic Considerations

Moderator:

As we are moving towards less invasive surgery and as Michael mentioned some of these transapical and transfemoral approaches to mitral valve repair, we have to I think remember the lessons we have learned over the years anatomically and physiologically so I would like to ask David to start with a discussion of those elements and then we will have discussion as we move towards a percutaneous solution.

Dr. Adams:

I wrote Greg a few weeks ago. I said Greg, thanks for the, you know, title and can you clarify it for me what you want me to do and I just want to read you what he wrote me back. For you and Sibal, I would like you to address the annulus, the coronary sinus relationship, and the basic kinds of leaflet management, address the spectrum of pathologies, and why good repair makes a difference. Do this in 10 minutes and go straight to the points. Okay, so that is what I am about to do while they are just pulling this talk up. I also had Michael in the OR last week with me at Mount Sinai. I learned a lot of tricks from him. I highly recommend either bringing him to you, which is easier or going to Liepzig. At any rate, so my goal here is to talk a little bit about anatomic and physiologic considerations in the context of percutaneous treatment. I have obviously been involved in ring design and development for annuloplasties but really they aren’t going to have anything to do this with this particular topic other than just to explain the annuloplasty.

Here is the next thing I got, this was back coming from Sibal. It says “Dear Dr. Adams and Greg, thanks for the invitation. I suppose it is going to be a little bit of a roast with all of the surgeons around” and then I like this at the end “I am honored to be there, just be nice to me.” So, I am always nice. This was the funny thing at the ACC, and I actually had been very interested in all the e-valve stuff and I know a lot of the guys doing it, they are all good friends, and I am interested in the technology but I also think we have to be a little bit careful about some of the hype and not necessarily coming from Ted for those of you that know him he is fairly excitable, but I think that, you know, we do have to step back a little bit and go back to sort of the basics when we talk about percutaneous therapy and I am sure that is what this panel is for. When we think about the mitral valve it is actually a very complex structure. I show this slide to every patient that I operate on and explain to them the nature that it is very careful and precise. Because of the pressure difference between ventricle and atrium, you need a long coaptation surface and because you have got chords, leaflets, papillary muscles, and the annulus and leaflet segments, you have got lots of lesions; very different in percutaneous aortic valve treatment where you are treating one lesion which is basically leaflet stenosis. So, you have different mechanisms of regurgitation; you can have primary annular dilatation, excess leaflet motion, restricted leaflet motion; you have can that in combination in degenerative disease, and of course in ischemic disease you can have leaflet restricted leaflet motion in systole and that can affect some segments of the valve or it can be a diffuse segmental restriction of all the leaflets, that is important.

Within the spectrum of prolapse; we have got to think very carefully about how much leaflet segment prolapses, so you can have fibroelastic deficiency with single-segment prolapse, you can see a picture where you have a normal segment, thin ruptured chord. In the setting of chronic prolapse, you will get myxomatous change in a prolapsing fibroelastic deficiency and that would lead to leaflet distention and thickness just in this one valve. That is the opposite spectrum; Barlow’s disease where you have large valve, the description; floppy valve syndrome. You have giant segmentation, you can have deep indentations, you can have calcification and restriction of papillary muscles and you almost always see some type of annular calcification whether it is early like this with fissures or whether it is real mitral annular or MAC with a horseshoe calcification. In terms of repair techniques, I do not really get hung up any more about this. In fact, after Michael visited last week, we did six loops last week just to get sort of our hands into it and learn how to get comfortable doing it and it is another good adjunctive technique. I do not think I will do all loops but I can tell you it is a pretty good technique for diffuse prolapse particularly in the anterior leaflet, so we tend to perform resections, lower the posterior leaflet height to a centimeter; we cannot resect the anterior leaflet. I think if you re-suspend the leaflet and think about height, as Michael and I discussed, it is leaflet displacement if you are trying to decrease the height to a centimeter and it is 3 cm. If you are just correcting prolapse and the height is the same then you are just re-suspending the margins, so there is a difference. Gore-Tex works well with both of them.

In terms of the annulus, we've got to keep in mind that the relationship around it and why we came up for instance, why C-shaped ring worked in lots of patients because you have this fibrous continuity between the aortic valve and the mitral valve. That is what defines the trigones which is getting up to this fibrous continuity with the aortic valve you have the coronary sinus below you and you have the circumflex and we will look at that again in a minute, and again when the annulus dilates it dilates in a very specific way because the curtains protect the inner-trigonal distance. When you say annular dilatation, what you should be thinking is an increase in the circumference of the posterior part of the valve, so that is why valves become more circular and they stay relatively fixed in the inner-trigonal distance except in dilated cardiomyopathy, which is now several studies, both pathologic and anatomic have shown that portion of the valve does dilate there and when we do annuloplasties they are always very measured. We are trying to match the surface area of the leaflet to the reduced circumference of the posterior part of the annulus, and even in Mayo where they say we just use the same-size band, I will argue most of those patients have fibroelastic deficiency where you are sort of in that range of 32 to 34, that band is 34, but it is a measured placation. Now when you look at the coronary sinus, I like this picture. This is one of those early pictures from one of percutaneous companies and of course we all know the coronary sinus does not get to the anterior commissure, so this is a problem. It is going to be an asymmetric plication. By definition, any of these coronary sinus techniques will not be able to narrow the A1 P1 area as well as the P3 area. That is one thing. The other thing of course is this issue of the coronary sinus and circumflex. The patients, if there ever is a technology we are trying to apply on the annulus percutaneously. A lot of patients are going to have the circumflex between the annulus and the coronary sinus. These will not be candidates for percutaneous annuloplasty because of the risk of kinking the valve. Now, Ted Feldman says that based on existing surgical approach, the use of the clips seems to accomplish a similar anatomic and mitral leaflet repair, and this was in the Everest Paper and I had a chance to debate Ted and I showed him a few of these slides. One of course we know that probably if you look at all the papers, this paper from Alfieri’s group, you look at Flaming’s paper, you look at Tyrone David’s paper, lack of not using an annuloplasty is probably the strongest predictor of failure after degenerative valve repair. In fact in the American Journal of Cardiology in 2005, Alfieri made the point that currently in his own series he feels less than 10% of patients could have an isolated edge-to-edge. We cannot say we are just copying the surgical technique because surgeons have moved beyond that and one of those reasons again as I mentioned at the beginning is that it is a multiple lesion problem when you have mitral valve regurgitation, and one of the first things I learned from Carpentier was one lesion one technique, there are multiple lesions you need to learn different techniques, and even with a loop you still need a ring. You have got to address the different lesions and it is very difficult to see how you can do that in unselected patients with any technology that can only address one lesion, so keep in mind there are differences in dilatations.

Here is a patient with atrial fibrillation, and they have a significant amount of posterior increase in their circumference. So you will see a lot of dilatation. That is different, for instance; in this patient all annuluses do not dilate the same. There is much less circumferential dilatation. This valve is not as circular in appearance, it is more fibrotic. The first case would be a better case for coronary sinus intervention, because you have more to plicate. This, a coronary sinus intervention, I doubt is going to very effective, you are not that dilated and you are not that displaced. This is a leaflet tethering issue. This may be a case where potentially a clip would work better although I would go back and always look at the literature. Here is the paper from the Cleveland Clinic combining Cosgrove bands and edge to edge with very poor outcomes in ischemic patients. So, we are going to have to learn how to select the ischemic patients we try it in. This might be a good patient to clip; this patient I doubt would be very effective with any percutaneous treatment, bileaflet prolapse, lots of excess tissue. Patients that have complex subvalvar pathology obviously are going to be better suited, I think by surgical techniques.

And just to close, because I am going to be nice, here is a patient who has a simple prolapse and let’s watch for a minute. My own humble attempt at edge-to-edge. So we have got predominantly a posterior leaflet prolapse, several ruptured cords, and I think this is instructive actually. I showed a similar video down at the ACC just to show cardiologists what you are looking at when you do this, so there is one, and we will test each time. Here is another one. This is direct vision, by the way, not echo guided. We are getting better. Here is another one. I am working fast because I have got to take all this out eventually. As I told my team, chuckling when I made this video, we put enough of these in, it would not leak. Nothing will get through, it will not leak, and you can see now honestly I have sewn a centimeter and half and look, that is the saline testing. You can tell where 2+ residual regurgitation comes from by definition. The alternative to that of course is an operation that really addresses the height of the posterior leaflet and the multisegment nature of that particular prolapse, so one of the reasons the edge-to-edge was not working there was because the adjacent segments had chordal elongation, and until we are talking that way, when we select which procedure for which patient we will never make progress. So you can see here we are going to address the height of all of the leaflet segments, and again when I move this leaflet it is just to put a little extra tension on the chords that are elongated to put them back in the right position, this would have easily been done with a loop technique as well but you need to address more than just those areas that just had ruptured chordae, so you can see this technique we use was a sliding plasty and how we measure a ring and the final results, so you can say well it is a much more invasive procedure. It is a much more precise procedure, but I think it will be good for the discussion because that shows us what we have to move toward, be careful about 2+ MR, it does predict recurrence of failure, so I think one thing we need from the e-valve data is longer follow-up to know what happens years 2, 3, and 4. The spectrum of complex disease is what we all have to appreciate and we have to get better at echocardiography because there are some patients that will benefit from some percutaneous technologies but they cannot be broadly applied.