A long awaited alternative to open-heart surgery

Since last October, three French centers have been performing percutaneous implantation of valve prostheses to treat aortic valve stenosis. This represents a source of unprecedented hope for tens of thousands of patients.

ROUEN CHU – April 2002. Prof Alain Cribier, Head of the Cardiology Department, and his team carried out the world’s first percutaneous implantation of a ventricular valve via the femoral vein. The patient was a 57 year-old man whose health condition precluded the performance of open-heart surgery and who, otherwise, had no hopes of surviving.  The success of the intervention exceeded our expectations. Indeed, the improvement in the patient’s status was immediate and spectacular. We had just opened a new way, with the hope of saving tens of thousands of patients, commented Prof. Cribier.
Although as many as 150,000 patients undergo surgical treatment of aortic valve stenosis every year, another 50,000 cannot be treated because of their advanced age, poor cardiac condition and severe co-morbidities. Up until now, these patients had no alternative treatment options.

A larger valve

From 2003 to 2005, 36 interventions were carried out: 29 via the transeptal femoral approach with an 80% success rate and 7 via the retrograde arterial approach with a 60% success rate. 2006 proved to be a turning point thanks to two innovative developments: a larger 26 mm valve preventing paravalvular leaks in the presence of large aortic rings and a new valve delivery catheter, the Flex catheter, allowing implantation via the femoral artery access.
This technique was used in more than 100 patients who had been denied surgery (ineligible for surgery) with a 90% success rate and a very low mortality rate (8% at six months).
Three major multi-center studies are under way in order to assess the efficiency of this treatment strategy: REVIVE (France, Germany, Canada) and REVIVAL (USA). ASCENDRA, another US study is currently being conducted to evaluate the apical approach.
The ROUEN CHU has been emulated recently by two other centers: Pr Alec Vahanian at the Bichat Hospital (Paris), and Dr Thierry Lefèvre (Institut Hospitalier Jacques Cartier in Massy) performed their first interventions in October (Year ??). The technique is entering a generalization phase, enthused Prof. Cribier. We hope to obtain CE market approval in 2007. Once the Phase II studies are completed, we expect the technique to be routinely implemented around 2009. At present, only patients with an estimated mortality risk in excess of 20% are offered this treatment option. In the future, we hope that we shall be able to treat all patients indiscriminately.

Numerous indications

About 15 manufacturing companies are currently developing valves. They are in the bench testing phase or being evaluated in animal models. Edwards LifeSciences, the company which designed the first valve, is working on the reduction of the bioprosthesis size, which will be compressed on the delivery balloon for improved introduction in peripheral vessels.
Denudation and suturing of the femoral artery require general anesthesia, which may be contra-indicated in some instances. Consequently, the objective is to perform an exclusively percutaneous intervention via the retrograde approach under local anesthesia.
In the future, the bioprosthesis could also be used in other indications.
The possibility of performing pulmonary valve implantations is being evaluated: the first intervention has been successfully performed in a human being by Prof. Hijazzi and his team in Chicago. Another potential indication is the treatment of degenerated bioprostheses.
This technique has also proved very promising in the treatment of aortic insufficiency by implanting the valve in the descending aorta instead of the native diseased valve.
Valves implanted via cardiac catheterization have been successfully used by Prof. Bonhoeffer in the treatment of pulmonary pathologies in children.
We are witnessing the beginning of a new era in the treatment of heart valve disease.

The day will come when interventional cardiology will supersede heart surgery for the benefit of our patients.

Degenerative aortic stenosis

Degenerative aortic stenosis is the most frequent valvular disease in adults. It involves 2% to 3% of the general population over 65 and its incidence increases with age.
The disease is characterized by the formation of fibrosis and calcium deposits on the leaflets of the aortic valve, precluding the opening of the valve and impairing blood injection from the left ventricle into the aorta. Breathlessness, chest pain and fainting are the first symptoms of this condition. The prognosis is extremely poor with a 2-year mortality rate of 60%.

Practising the technique with a simulator

Percutaneous implantation of artificial heart valves is a complex procedure which requires a high level of technical skills and which cannot be improvised. An interventional cardiologist at the Institut Hospitalier Jacques Cartier, Dr Thierry Lefèvre has been using this technique for several months. Before carrying out his first intervention, he underwent rigorous training for several months. As he recalls ‘I started by attending procedures in Rouen and Vancouver, in centers where the technique was already mastered. I then performed several interventions on a simulator. This is a very elaborate mannequin in which one can advance a guide wire, inflate a dilatation balloon and perform programmed ventricular pacing. This training method is very efficient and allows you to learn from your mistakes without the pressure induced by working on a real patient’.

When carrying out his first interventions, Dr Lefèvre was accompanied by John Webb, the leading American specialist in procedures via the retrograde approach. This was an ideal way of benefiting from enlightening advice with optimal safety.