Mitral valve regurgitation is a frequent disease of heart valves. It is especially common in elderly patients. You are a leading heart surgeon in minimally invasive mitral valve prolapse treatment. So today, what treatment options exist for patients with functional mitral valve regurgitation? How to treat the primary structural mitral valve regurgitation? What would be the difference in indications for treatment between the two causes of mitral regurgitation?

Okay, it's a good good question. It is a good idea to divide these two fields, which are very similar because they all relate to the mitral valve. But basically, they are very different. And also, the treatment strategy is totally different. So let's start with the primary mitral regurgitation because probably it is easier. Primary mitral regurgitation is mainly due to the so-called genetic mitral valve prolapse. In this prolapse category, there are some subcategories. The classical division is the degenerative mitral regurgitation due to fibroelastic deficiency, which means the mitral valve is almost normal. There is one lesion, one single lesion, which is usually a chordae tendineae rupture. There is a flail area. Usually, it is a P2 flail lesion. This is the most commonly found lesion. It is in the middle of the posterior leaflet of the mitral valve. But the mitral valve itself still looks normal. There are thin valvular leaflets, and there is no calcification of the mitral valve. There is no redundant tissue in the mitral valve. Then at the other end of the spectrum, you have the so-called Barlow's mitral valve disease or myxomatous disease. There the mitral valve is totally and grossly altered. There is a huge alteration of all mitral valves, which has redundant tissue. The Mitral valve is thickened with multiple lesions, multiple prolapses. Then you have all the intermediate forms of mitral valve disease.

So even the degenerative mitral regurgitation is not one disease, but it's a continuum of disease. So finding the cause o mitral regurgitation is one side one of the issues for making correct decisions in the field of mitral regurgitation treatment. The other parameter in treatment decisions is the clinical condition of a patient. So degenerative mitral regurgitation is usually a disease found in relatively young patients. In particular, Barlow's mitral valve disease is found in patients between 40 and 55 years of age. This is what you see in these patients with mitral regurgitation. You can see even much younger patients than that age. In this young generation, I think, open-heart surgery remains the best solution for most patients. It is so mainly because Barlow's mitral valve disease is a disease that is very diffuse. And quite often, we need to do more than one surgical maneuver to treat the mitral valve in addition to mitral valve annuloplasty. This can be done today by a very minimally invasive approach. On most occasions today, for Barlow's disease surgical treatment, we use a videoscopic approach with a periareolar incision.

At the moment, we have not been active with a robotic mitral valve repair, but robotic mitral valve surgery is just a solution that is more intuitive for the surgeon. If you have enough experience with minimally invasive approaches and using long instruments, there is not much advantage of robotic mitral valve surgery. The only advantage, a real advantage of robotic mitral valve surgery, is in education. Because you can teach other surgeons easily, you can see and really follow the surgeons doing robotic mitral valve procedures. And for some complex cardiac surgery procedures, it's nice to have advanced technology.

So if you have a patient with degenerative mitral regurgitation in a young patient, if there are no comorbidities, I think there is no discussion that open heart surgery remains the gold standard of treatment, at least today. But there are many patients who are older and who have the genetic mitral valve disease. They have one or two lesions or even more in their mitral valve. And today, we can treat these patients pretty easily with specifically transcatheter edge-to-edge mitral valve repair. We have different tools for transcatheter mitral valve repair. There is MitraClip. There is Pascal. There are some other methods of transcatheter mitral valve repair coming from Asia. Today, every patient, almost every patient, can be treated with these technologies in good hands. It is not the simplest technique to treat degenerative mitral regurgitation with a transcatheter edge-to-edge mitral valve repair. But after doing many cases of mitral valve regurgitation treatment, I can provide a good service to most of our patients.

Well, there are also other things. But let's make it simple. So in principle, degenerative mitral regurgitation has mainly a surgical solution. The treatment of degenerative mitral regurgitation becomes an endovascular alternative for those patients who have a less ideal condition for open surgery. These are the elderly patients, patients with comorbidities, and so on. And every patient should get out of these procedures with no mitral regurgitation, no mitral stenosis, and no residual anatomical lesions. These should be the objectives of treatment of mitral regurgitation. This is an objective that can be reached in every patient. If we project into the future, I predict that we will see more and more endovascular treatments even in low-risk patients with mitral regurgitation. There is a clinical trial going on at the moment.

Functional mitral regurgitation is mainly today in an endovascular treatment domain. Unless the patients have combined pathologies, even the latest guidelines declare that. In combination with other indications, for example, coronary artery bypass grafting (CABG) or aortic stenosis, functional mitral regurgitation can be treated surgically. But also the latest treatment guidelines state that a staged approach with endovascular procedures can also be achieved. So we are also moving in this field of endovascular treatment of functional mitral regurgitation. When we go into functional isolated mitral regurgitation or isolated tricuspid regurgitation, I think there are very few indications for open surgery. Maybe open surgery can be done just in tricuspid valve regurgitation in patients with very well preserved right ventricular function and no comorbidities. Today tricuspid valve regurgitation is still in the early stage.

So tomorrow, I will operate, for instance, on a 70-year-old lady. Otherwise, she is in good condition. She has a good right ventricular function. I am sure that tomorrow we will be able to abolish tricuspid regurgitation in this patient with a minimally invasive surgical approach. But on the other hand, I know that in three to four years from now, this patient will never get the open heart surgery anymore because I can do a transcatheter annuloplasty the same way as I do it now surgically. I can do transcatheter edge-to-edge valve repair in the same way as I do it now surgically. I can implant a new heart valve by transcatheter method about the same way I can do it surgically. So as the expertise improves and increases in tricuspid valve treatments, we will see more and more endovascular procedures also in tricuspid valve treatments. Isolated mitral functional regurgitation [is now rare]. I don't remember any patient I treated in the last few years who had only functional mitral regurgitation. Maybe they also had atrial fibrillation; maybe they needed coronary artery bypass grafting. But isolated functional mitral regurgitation has been one of our main treatment topics for many years, but now it is disappeared.

So the minimally invasive approach is mostly what's dominating the mitral valve regurgitation treatment at the moment.

Yes, I think minimally invasive treatment in surgery means mini-thoracotomy and video system mini-thoracotomy with or without a robot. Or it means totally endovascular treatment on a beating heart. So these are the two areas where you can see a solution for these patients. And in most occasions, we're talking about heart valve repair. Now heart valve replacement is emerging in endovascular treatment methods. Specifically, I think in tricuspid valve disease, the repair solutions are still not so perfect. And will tricuspid valve replacement become more and more available? Will this change our perspective on the treatment of tricuspid valve disease? I don't know.

I had made my prediction already a few years ago. I was already asked more than five years ago that question. Once tricuspid heart valve replacement technologies will become available, will heart valve repair disappear? And my answer from a few years ago is the same today. Maybe heart valve repair will disappear, but the safety profile of heart valve repair is higher. But obviously, we will probably see similar situation to cardiac surgery in the 1950s. Then there was no mitral valve replacement available. And so, all heart valves were repaired. Then mitral valve replacement became available, and all cardiac surgeons abandoned heart valve repair because it was difficult and unpredictable. And so they said, okay, let's do something predictable. Let's pull a heart valve it out. And over time, we realized the limitations of heart valve implantation. So many surgeons became again interested and started to repair heart valves again.

Today mitral valve repair in degenerative mitral regurgitation is the gold standard. So we will see what happens. But I predict that in the next five years, we will see growing numbers of patients who have mitral valve replacement because it is less operator-dependent. So the heart valve replacement is more predictable for us. If I try to repair a heart valve, and the repair doesn't go well, it's my fault. If I implant the heart valve and the valve does not work, it is the fault of the heart valve. So for many operators, it's better to go for heart valve replacement. It is more predictable and less operator-dependent. But we all know that there are some drawbacks with mitral valve replacement. And the safety profile of heart valve replacement even today is not the same. So I personally try to repair every heart valve I find on my path. And this means a lot of work in some cases. But at the end of the day, there are many advantages of heart valve repair versus replacement.