 Hello everybody and too many of your humbling words. I consider myself a normal regular human being. I always say I bleed when I'm cut and I have a disclaimer. I do not belong to the elite group of surgeons who never have complications and never have failures. I do have them. I simply try to learn from them. And this brings me to the topic of today's talk. Thank you for inviting me. It's a pleasure. It's an honor. Erotic Velve Repair. Let's take ourselves back. And I apologize. I tried to follow the previous lectures not to duplicate too much. I did not catch everything because I was hosting a few guests during my vacation. If we treat or if we treat erotic valve we do it either for aneurysm or for regurgitation or for a combination of both. And we need to keep in mind that both root and cusp pathology contribute to erotic regurgitation. Erotic repair is not really new. The first attempts were done in the 50s published by Dwight Harkins group. And then there were further pioneering attempts by Carlos Duran and Toby Kostrov. They had initially good results. Erotic repair gained more popularity with the operations designed by these three colleagues. Bob Schroeder, Sinotubler Junction Remodeling, Tyrone David of course and Magdi Jakub. We all know them. And Tyrone and Magdi designed operations specifically made for the enlarged roots. The general assumption behind these operations was that erotic regurgitation was mainly due to erotic dilatation. And by normalizing erotic dimensions normal erotic valve geometry and function should be achieved. In other words, one size fits all if you choose the right operation. And if the result is not a good one you've chosen the wrong operation. At that time, and that's the common denominator of these pioneering series, the main goal was that all cusp margins should be at equal height for competent valve function and co-optation height should be high enough for a secure diastolic function. This is also how I started when I embarked on the erotic valve repair and actually one of my first operations was a David operation after I saw Tyrone do these operations 30 years ago. Let us come back to this co-optation height should be high enough for secure diastolic function. Only in the last 15 years some surgeons have been a little more specific. And you've probably heard the concept of praying hands as the appearance of a normal erotic valve. How high is high enough? How to pray? And there are different ways of praying. So I initially, as I said, started the same way as the other surgeons also. I started re-implantation in Hanover and when the group in Hanover published the early results of the first 100, I contributed 30 of these, they found that there was a correlation between valve configuration and valve durability. They contributed that only to the level at which the valve was re-implanted within the graft. And I do not really agree. After all, I contributed a few failures and I re-operated them even though I still for some years did not understand the mechanism of regurgitation. It was only a few years later when I reviewed our early experience with preservation of the bicuspid valve that I realized that there was something funny about valve configuration. So I had some patients for out of the first 60 some that I had to re-operate within the first two to three years because of regurgitation and all four had had valve preserving erotic replacement and all four had this abnormal valve function that simply looked funny. I went back to the initial operation and actually they had left the operating room with that funny configuration. These failures made me review, do my homework, review what was known. Of course, there is the study by Swanson and Clark Circulation Research 1974. They came up with this complex set of numbers that the normal erotic valve should have. I simply thought that this was for me too complex to use it in the operating room. So again, based on the failures which had an abnormally low height difference between the diastolic between the free margins of the cusp and the annular plane in diastole, I hypothesized that this height difference, which we call the effective height, could be used as a configuration parameter. This is something that a surgeon can measure in the operating room if he has a caliper to go for it. This can be determined by echocardiography and once we had the parameter, we decide to calibrate it. So we did a study on 130 some volunteers, different age groups, most of them were adults and we realized that in a normally functioning erotic valve, this effective height was 9 to 10 millimeters. Later studies confirmed that and in relation to cusp size or geometric height, we realized that it should be roughly 45 percent of geometric height. Again, we were not the only ones. Let me show you this table taken from a publication from out of Brussels. They did not call it effective height, they called it distance from tips to annulus and the first version of the paper, I was one of the anonymous reviewers simply said co-optation height is important. I then asked the authors to go back and look at this parameter and as you can see here, actually there were a little on the low side, if they had an effective height of 7 millimeters, at least within short to mid-term follow-up valve function was okay. If effective height was even lower, they had a relevant proportion of failing erotic valves. Now, when I first proposed to use effective height, it was also clear that this must be related to cusp height. Cusp height, for instance, being reduced in retraction in retracting valve disease. This valve pathology, this cusp pathology had been shown to be associated with decreased durability by the Brussels group. I tried to reproduce the data and then realized that actually we did not have any data, any cutoff to base this on. So we went back to do our homework. In a prospective clinical study, we studied geometric height in bicuspid and tricuspid valves, that is height in the center of the cusp from the nadir to the free margin in a stretched version. And then the bicuspid, and this is important in order not to be mixed up, we mainly measured the nonfused cusp. As you can see here, we found the distribution of geometric heights. In tricuspid valve, the mean geometric height was 20 to 21 millimeters. In bicuspids, it was actually 24. And to come back to the previous presentation, we arbitrarily defined then 20 millimeters for the nonfused cusp in a bicuspid valve or 17 millimeters in a tricuspid valve as the minimum that we would want to have in order to achieve a functioning valve. So if we look at the aortic valve in a different way, and this is taken from computer simulation studies done by Jill Moran in Tel Aviv, if you have a low geometric height, you will have limited co-optation. The same, however, will also occur if you have annular dilatation, or if you have sinus tubular dilatation. In other words, there is a complex interplay between root and cusp geometry that determines aortic valve form and thus function. Sinotubular junction is important, virtual basal ring, or the annulus, the functional annulus is important, the geometric height is important, and the effectified is nothing but a simple and reproducible configuration parameter that allows us to assess the complex structure. There is a different way of looking at the aortic valve, and I'm sure you're all familiar with this classification, which is frequently quoted. I do not use it very often, actually I rarely use it, because in my mind it has relevant limitations. Number one, it's purely echocardiographic. It does not directly relate to morphology or pathology. It does not, for the same reason, provide morphologic cutouts for decision-making that the surgeon has to do. More important, it's insensitive in defining cusp prolapse in the presence of marked aortic dilatation. In other words, if the cusp is stretched and the root is dilated, cusp prolapse may evade preoperative studies. And the type three does not differentiate between restriction due to aortic dilatation and restriction due to cusp retraction. So let us come back to these limitations. Valve-preserving aortic replacement, sinus tubular junction will be reduced, and this will lead to a reduction of effective height, simply because you bring the two commissures closer together, and the center of the cusp margin will hang down through. So in other words, reduction of root dimensions, that is inter-commissural distance, may induce or will induce or unmask prolapse. In other terms, if the root is dilated, if we reduce sinus tubular junction, or if we interfere with sinus tubular junction as part of the operation, we must check effective height after restoration of root dimensions. How frequent is that? I went back, and these results are accepted in heart, I went back into over 650 root aneurysms, primarily to see the frequency of cusp alterations. As you can see here, these cusp dimensions were determined after root replacement. Of course, there were some reasons why we replaced the aortic valve. In the vast majority, roughly 90% we could preserve it. However, in 85% of instances, we found prolapse after we had reduced aortic dimensions. So to have normal cusps at the end of a valve preserving root replacement is actually an exception and not the rule. Let me show you what the surgeon can do in the operating room to assess that. This is a tricuspid valve with severe AR normal root dimensions. The surgical assessment is quite simple. We measure geometric height on all three cusps. It's 20 millimeters and thus normal. There is not much angular dilatation. And now we go into measuring effective height. It's nine millimeters on the left, it's seven millimeters on the non, and it's close to zero on the right. So with this simple measurement, we can come up with a diagnosis of marked right cusp and mild non coronary cusp prolapse. The same, of course, we ideally do by echocardiography, first determining the aortic dimensions. And you're all familiar with that. However, if you do this in a long axis view, you have to consider that there may be projection artifacts because you're simply off center. For this reason, we have made it routine to double check these measurements by going into a 3D data set with multi planar reconstruction. And as you can see here, all of a sudden, the root diameter of an annular diameter of 3.4 will turn into a sinus diameter of 3.2 will turn into a sinus diameter of 3.6 centimeters. This has implications because beyond a sinus diameter of 40 to 43, 45 millimeters, root replacement is probably warranted in order to achieve a competent aortic melt. So this is important for the patient who comes to the operating room for AI. Annular diameter, we need to measure for the reasons I showed you. Again, we may have projection artifacts if measured in long axis view, and there may be artifacts due to the elliptical shape. Again, if we go into a 3D data set, multi planar reconstruction, the annulus will increase in this case, same patient from 3.2 to 3.4 centimeters. The mechanism of regurgitation is important. And jet eccentricity is an established indicator of cusp pathology. However, a jet may be due to prolapse or retraction. And the jet you see in the echo image may either be due to prolapse of the right cusp or retraction of the non corollary. Can we differentiate between the two? Well, first the differentiation is important. Prolapse in general is a very good substrate for repair. As you can see here, and this is as yet unpublished, all isolated tricuspid aortic belts, normal roots, the majority of the cusps with prolapse can be repaired. Whereas in the majority of instances with retraction, probably replacement is the better choice. Prolapse can easily be corrected, like with these placating sutures, but which reduce the amount of tissue redundancy and stepwise rebuild a normal cusp dimension. Again, can we do that in a systematic fashion, like the surgeon does it in the operating room? Let me show you this 2D example of geometric height determination. And in the bicuspid, always of the nonfuse cusp, you can see in 2D, we here have a geometric height of 19 millimeters. If we apply the same in this bicuspid valve in a 3D data set with MPR, all of a sudden we have a geometric height of 2.6 centimeters. And for this bicuspid valve means this means that we have a substrate, which is very likely to be to result in a good repair result. We can also quantify prolapse by measuring effective height. Again, we can do it by 2D, but this will result in artifacts because we have to do it in an echo plane that is orthogonal to the respective cusp. The same patient, the same valve here once measured 5 millimeters in 2D will be 8 millimeters in a 3D data set, and thus almost normal. There is something special about the bicuspid valve, which makes up roughly 40 percent of valve preservation in our experience. And here we learned from the stakes or failures of the past. As expected and already shown, an effective height of less than 9 millimeters indicating that we left bicuspid prolapse, symmetric prolapse behind, was associated with a poor durability. And this was mainly the case in patients with isolated aortic valve repair, where we simply had a durability inferior to those where we did aortic replacement in addition. In these patients, annular dilatation here with a 29 millimeter cutoff, which is probably too large, resulted in absolutely unacceptable, unacceptable durability. And we also found that commissural orientation played an important role. Symmetric bicuspid valves giving us excellent long-term durability, the asymmetric bicuspid valves faring much poor. What can the surgeon do about that? Annular plastic has been mentioned, and rather than trying to implant a ring either externally or externally, we have chosen the way of a suture annular plastic in order to better accommodate the different muscle extension into the sinus that we see particularly in bicuspid valves. And as you can see here, the addition of an annular plastic largely eliminated the failure rate after bicuspid repair. More importantly, we try to bring more systematics into the commissural orientation of bicuspid valves. And this is from a essentially double center study, Brussels and Homburg, where we looked at the type of symmetry. The symmetric bicuspid valves arbitrarily determined as 160 to 180 degrees, found in roughly 40%. Another 40% with asymmetric bicuspid valves. And then 20%, they vary asymmetric bicuspid valves. They usually have partial fusion and often are mistaken as tricuspid on echocardiography. Can we do something about the symmetry of a valve? Yes, of course, we can do root replacement, like in the cases that were shown in the previous presentation. If the root is not enlarged, I find root prophylactic root replacement overly aggressive. And my idea was if we simply eliminate part of the circumference in the few sinus by placating the sinus, we should be able to improve the symmetry. We actually could improve the symmetry. And by doing that and adding an annular plastic, we could find that even in this high risk group, we could achieve excellent durability. Not only that, not freedom from AI and reoperation was improved, but also systolic valve function with lower gradients if we achieved a more symmetric results. The key question now is how can we most easily or most reproducibly determine commercial orientation? And I've seen a number of presentations where at first sight, I was not absolutely certain I would agree with the determination. The key is determining the center of the root in order to be able to then determine the connoisseurs and the angle. That's easy. That's what modern echocardiography machines can do in the operating group. There are different ways of approximating this bicuspid root we used in ellipse, we used a circle. And with the help of my oldest son, who is an engineer, we finally decided that the easiest was simply to draw a line from the center of the nonfuse to the center of the fuse sinus, cut it by half. And this would show us in a very reproducible way the center of the root and allow us for more reproducible determination of commercial angles. The therapeutic consequence is clear. If we have a symmetric bicuspid valve, we simply keep it symmetric. If we have an asymmetric, we make it symmetric. The challenge is the very asymmetric bicuspid valves, where we can either treat it as a tricuspid valve, or we have to improvise. The consequences are relatively clear. This is from a paper that we published recently in German cardiology, more than 1,000 patients with bicuspid repair. Without addressing these anatomical details, there was continuous attrition of valve function, which could be largely eliminated by addressing these anatomical features. The good side is if we choose this geometric approach, which was based on the analysis of failures, we can preserve the aortic valve in the vast majority of patients with root aneurysms, whether the valve is tricuspid or bicuspid. One of the more recent findings, and this came from a paper where we analyzed isolated tricuspid aortic valve repair. The fact that we used the measurement of effected fight intraoperatively was a predictor not only of better valve durability, but also of better survival. Let me summarize. Aortic valve form is like a function can be mathematically described as a function of cusp and root geometry, and we need to keep in mind that valve preserving surgery is only one form of aortic valve repair. There are others, and we simply have to address the individual pathologic components. Systematic analysis and correction is clear. It's logical, and also it's logical that adequate valve configuration translates into durability. Practically speaking, the most important is to rule out retraction as a poor substrate for repair, and this is where geometric height has been very helpful, and in normalizing cusp configuration, the measurement of effective height has been very reproducible and is increasingly adopted by different groups around the planet. Specific valve configurations may occur, and we need to keep that in mind if we try and come up with a tailored approach. My suggestion, and this goes more to surgeons than cardiologists or anesthetists, we should also report more details of the analysis of these valve geometry in order to make our findings reproducible. Thank you for your attention.