Mitral valve prolapse is often treated with open-heart surgery. But recently, the minimally invasive percutaneous transcatheter mitral valve repair methods also appeared. It is a very promising therapy for mitral valve regurgitation. Your team, together with Professor Ottavio Alfieri, developed a particular percutaneous method of mitral valve repair. It's called MitraClip. What is MitraClip and how to use MitraClip in the minimally invasive treatment of mitral valve prolapse?
So, first of all, a MitraClip is designed to reproduce the so-called Alfieri technique. And today, we should talk about transcatheter edge-to-edge repair, or TEER. This is the name that is in the treatment guidelines today because transcatheter edge-to-edge repair can be done during the same operation with different technologies. MitraClip is one method, which has been mostly used today. Pascal is a similar device for transcatheter mitral valve repair, making the same approach. It's the approximation of two leaflets of the mitral valve. One mitral valve leaflet is moving too much or too little, so either it's a prolapse, or it is a tethering. You can put the two leaflets together, join them with one device, which is a clip a clasp, or whatever. They you try to put the two valvular leaflets together. And in this way, you obtain the coaptation of mitral valve leaflets. You force the coaptation at the site of the mitral valve regurgitation. This is the concept of the Alfieri technique of mitral valve repair. The Alfieri technique has a huge advantage over any other techniques of mitral valve repair. Alfieri's edge-to-edge valve repair method is so versatile. It can be used in mitral valve prolapse. It can be used in functional mitral regurgitation. It doesn't matter that happens below the mitral valve. The valvular leaflets are joined together, and this creates the solution.
MitraClip was developed in the early 2000s. It was developed during the late 1990s. They started the evolution of the development of this technology. And it is, basically, a clamp. It is a clamp that clamps the two valvular leaflets together. The clamp is introduced into the body under fluoroscopic and echocardiography guidance. The patient will be in general anesthesia with transesophageal echocardiography. It will be producing the images that we will use for the implantation of the MitraClip. We cross the septum. We get into the left atrium. We go in the front of the mitral valve, we open the MitraClip clamp.
The MitraClip is basically made of two arms, which are opened with this device. It goes into the inside of the mitral valve it clamps the leaflets. The MitraClip is closed, the leaflets are approximated, and they are joined together. All this is done under physiologic conditions. And that's the beauty of it. Because compared to open-heart surgery, where we operate on a non-beating heart, we can do things that are fantastic, but we need to be very smart. We need to predict how this anatomy will react to beating heart conditions. So we cannot see the effect of our intervention until we close the heart and we wean the patient from a cardiopulmonary bypass machine. In MitraClip, it's all done on a beating heart, online. What you do is what you get. You see immediately the effect of your action. And you can adapt MitraClip to the patient's condition and patient's anatomy. If you don't like the effect, you can release the MitraClip clamp and start in another position. And you are guided during these decisions by the hemodynamic effects of your MitraClip implantation.
To some extent, it is a simplification of surgery. To some extent, it is even more than surgery. You know it is a very hemodynamically- driven intervention. That also requires quite a lot of experience to make the right decisions during MitraClip transcatheter mitral valve repair.
Also, there is an opportunity to do MitraClip. But there is another technique called percutaneous annuloplasty. What are the advantages and disadvantages of MitraClip and percutaneous annuloplasty? How do you compare these techniques and apply them to the right patient with mitral regurgitation?
So, annuloplasty. I have been developing one of the tools to reduce the size of the annulus [of mitral valve]. First of all, annuloplasty is a surgical technique that is done in every mitral valve repair in open surgery or minimally invasive surgery. So it is very commonly done. And the reason is that the annulus, which is basically connected at the base of the heart, is found dilated in almost every patient with mitral valve regurgitation.
For this reason, there is a need to reduce the size of the mitral valve annulus because there is a mismatch between the size of the valvular annulus and the size of the valve leaflets. The annulus is so dilated that the leaflets cannot touch each other anymore in the middle. And this has two consequences. One consequence is mitral valve regurgitation. Opposite they don't touch. The second consequence is that there is a lot of stress on this difference. Even if you join them, let's say with the MitraClip, you can create a lot of tension there. Eventually, you may break, or you may damage the valvular leaflets. This also happens in surgery.
If you do a procedure without annuloplasty, the tension remains there. And you can have a tear of your reconstruction of the mitral valve. For this reason, by using the annuloplasty, you bring the leaflets together, you re-establish a good balance between the size of the annulus and the size of the mitral valve leaflets. And then you reduce the stress on the system. So, annuloplasty, in principle, could be done in most of the functional mitral regurgitation patients. Specifically, it can be done in the early stages before the ventricle becomes very dilated. Because in the early mitral valve regurgitation phase, the mitral valve leaflets are still not too much pulled down into the left ventricle. I still believe that in the future, annuloplasty could become the leading solution for those patients undergoing procedures early in their disease stage. The other advantage of annuloplasty is that it gives a very little footprint in MitraClip, or any clip-in device will stay in the middle of the heart valve. This will be creating anatomy which may prevent other treatment options like mitral valve replacement. We already have solutions for that, but in principle, it makes things more difficult. An annuloplasty is only a reduction and normalization of the annulus. So basically, you can do anything after that. You can put a clip. You can put a valve replacement. We have already done many cases. So, these are the advantages. The main disadvantage of transcatheter annuloplasty today is the complexity of the procedure. The imaging is not ideal enough for these procedures. The transcatheter annuloplasty devices are still in the first generation. The second generation has not yet arrived. As soon as we have the second generation, probably they will become more operator-friendly and therefore also safer. At the moment, because of the difficulty of imaging, because of the difficulty of the handling of transcatheter annuloplasty, there are still too many adverse events. We have too many cases of coronary artery injury. We have too many cases of insufficient implantation of the annuloplasty device. We also have some cases of suboptimal outcomes. So transcatheter annuloplasty is not yet the solution for every patient. And then the other limitation of annuloplasty today is this. If a patient comes to the hospital as an emergency, and if I need to do something now, I can do a MitraClip procedure immediately. I don't need any preprocedural planning.
Transcatheter annuloplasty needs, at this moment, cardiac CT scan planning before the intervention. So the availability of annuloplasty is another limitation. This is similar for annuloplasty and for mitral valve replacement. But again, in the future, I will not be surprised if annuloplasty becomes more and more utilized in the in the atriogenic forms. First of all, there are many patients we normally left ventricle and large atria. And this can be used both in the mitral valve and in the tricuspid valve. Annuloplasty can also be used in functional ventricular mitral regurgitation or tricuspid regurgitation in patients in the early stages of mitral valve prolapse, where there is not much tethering of valvular leaflets.