By Dario Remigi
The technique of implanting heart valves through a percutaenous approach finds its origins in the double balloon technique for dilatation of valvular stenosis, first performed by Alain Cribier in 1985, to provide solutions for high-risk patients. However, in the year following surgery using this technique, a high rate of severe valvular restenosis occurred. The procedure was finally replaced by the coronary stent implantation technique at the end of the 1980s. The technique, which also posed a high risk to patients, gradually gave birth to the polyurethane valve, developed in the 1990s and finally the heart valve implantation technique in 2002.
Alain Cribier spoke to Cardiovascular News International at the 3rd Indo-European Course on Revascularisation, held on 3 and 4 November 2009 at the George Pompidou Hospital, Paris, France, about the evolution of percutaneous techniques.
Cardiovascular News International: How have transcatheter valve implantation techniques evolved?
Alain Cribier: As we had no guarantee that the use of polyurethane valve could be possible, we decided to perform a bovine pericardial valve transplant, as we knew that it was a suitable match with the human immune system.
Thanks to this first prototype bovine valve, 100 animals (ewes) were treated at different cardiac sites, to demonstrate that the valve could be efficient on animals when implemented in vivo.
So finally, in April 2002, we treated a patient in Rouen who had a typical profile for valve implantation. This patient, at 57, was quite young. He had developed cardiogenic shock and could not have any surgery. So he was the first patient to be operated on using this technique through a particular procedure, the transseptal antegrade approach.
From this successful operation, which attracted massive media attention because it was considered an important step in the medical field by all medical practitioners, we started to apply the transseptal antegrade technique on a series of patients that were seriously affected. It was only after the company that we created was bought by Edwards, that it became possible to develop techniques that we currently use, such as the transfemoral retrograde arterial approach and the transapical approach for patients who could not be operated on with transfemoral valve implantation. These considerable medical advances have allowed this technique to be used succesfully in cardiovascular and surgical departments.
CNI: Do you think that the percutaneous technique can be considered for patients who at the moment can be only treated through traditional surgery?
AC: This is what we have demonstrated. So far, a series of surveys and post-marketing surveys have demonstrated that this technique could only be successful on patients who are not in a healthy condition, that is to say, high-risk patients. At the moment, high-risk surgical patients or patients who have been not recommended for surgery, are the only ones who can benefit from transcatheter implantation. So it has to be clear that, at the moment, only high risk patients can be treated through the percutaneous technique.
A recent survey, called Partner US, has been conducted to compare transfemoral and transapical techniques, and the traditional techniques over high-risk patients. This survey is now finished and we are now waiting for the results, due in 2010. The results will be crucial to allowing us to find out if transcatheter techniques are more suitable than open heart surgery for high-risk surgical patients.
CNI: In the light of this, what is the future of the percutaneous method?
AC: Well, the percutaenous technique in five years will certainly be very promising because there have been considerable medical advances, which have allowed us to reduce the amount of equipment used and therefore make its application easier and safer through the transfemoral approach. We are progressively moving to a technique close to coronary stent implantation, which is performed in cath labs under local anaesthesia. So technically I think that advances have been massive, especially over the last year. In addition, the transapical technique remains suitable for all patients for whom the transfemoral approach would not be possible. So I think that the future of the percutaneous technique is very promising but the only problem at the moment is the durability of the valve. This is one of our main concerns. We have managed to show that the technique could be done, we know that the results are immediate and satisfying in the short term for these high-risk patients. However, we are very uncertain regarding the durability which is the last parameter to explore before considering whether to operate on patients.