by Dario Remigi
Transcatheter (or percutaneous) heart valve implantation is considered a technology with enormous clinical potential. The percutaneous implantation of a pulmonary valve in a human was reported for the first time in 2000. The first ever implantation of an aortic valve via transseptal antegrade approach was performed by French cardiologist Alain Cribier in 2002. Since then, transcatheter heart valve procedures have recorded constant double-digit growth year on year, as an increasing number of centres have introduced this programme, offering a new option to candidates not suitable for conventional surgery.
While an increasing number of hospitals across Europe are performing these new procedures, a number of cardiovascular and cardiothoracic specialists have raised concerns about complications associated with transcatheter aortic valve therapy, and valve durability, which is currently unknown.
Despite the potential room for expansion, it is still unclear whether transcatheter aortic valve implantation (TAVI) is set to become a widely-used technology in the foreseeable future.
The issues prohibiting the wide-scale uptake of the procedure include concerns raised by physicians on valve deployment and para-valvular leakage. In addition, greater follow-up data are needed as the durability of valves in younger patients may be an issue. The dynamics of public healthcare expenditure (reimbursement, health technology assessment, pricing pressure) may also be an issue. Valve prices range between €20,000 and €25,000, depending on the country in question. This is approximately five-times as high as traditional surgery. The German diagnosis-related group tariff, which started in January, 2010 has set to €35,000 the reimbursement tariff per single transcatheter heart valve replacement or repair procedure.
Massimo Mariani, cardiac surgeon, Thoraxcenter University Medical Center of Groningen, The Netherlands, said, “Procedures are not reimbursed by the public health system. Cost of valves and low success rate of procedures are an obstacle to wider penetration.”
The age and profile of the patient can also be an obstacle. In younger patients with no additional risk factors, conventional heart surgery is “so safe and so effective that it cannot be replaced,” says Thomas Walther, associate director at the Leipzig Herzzentrum, Germany, which is one of the busiest centres in heart valve treatment. “Mortality rate in TAVI is between 5 and 10%, whereas conventional heart surgery has a mortality rate of 3% or lower,” he said. On the other hand, the higher mortality rate in TAVI can be explained with the higher risk factor/worse patient profile.
It is believed that from a limited panel of pilot centres performing TAVI procedures in 2004–5, the number of centres across Western Europe is now over 250. A certain number of centres told Cardiovascular News International that they intend to start performing transcatheter heart valve procedures within the next 18 months. The number of procedures including aortic replacement, pulmonary replacement and mitral repair have reached the 8,000 unit-level a year as at end of 2009, driving a turnover of nearly US$250 million.
The transfemoral technique accounts for more than two-thirds of the total number of transcatheter valve implantation and repair procedures, double their transapical equivalent. The subclavian technique accounts for just 3%. “I can see a shift towards transfemoral approach, as catheter techniques improve,” said Sunil Ohri, cardiac surgeon at Southampton General Hospital, UK.
The operating theatre has seen a prevalence of cath labs compared to operating rooms so far (cath labs 67%, operating room 26%, hybrid room 7%), reflecting the fact that interventional cardiologists were involved in 98% of transfemoral and in 74% of transapical procedure cases. Mitral repair procedures have seen a prevalence of cardiac surgeons compared to interventional cardiologists.
All candidates undergoing transcatheter aortic valve implantation were not suitable for traditional surgery. A very limited number of clinical trials including non-high risk patients have been reported. Follow-up data from a Denmark-based clinical trial including 140 non-high risk patients are expected within the next three years. In the pulmonary replacement, as well as in the mitral repair associated with congenital heart disease, the percentage of candidates suitable for surgery is significantly higher compared to those ones in the aortic valve segment.