Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Percutaneous aortic valve replacement

05.09.2005


Percutaneous aortic valve replacement is becoming a reality and brings new hope for a number of patients who cannot currently be treated with traditional surgical techniques.



Whereas surgical valve replacement concerns about 200,000 patients worldwide every year, it is estimated that between 1/3 (Iung et al, Euro Heart Survey, 2003) and 2/3 (Rambas Pai, USC AHA 2004) of patients do not receive surgery due to either excessive risk factors and comorbidities or patient refusal due to fear of lifestyle changes following heavy surgery in elderly patients. The size of this untreated cohort is expected to increase, reflecting the aging population. However, without replacing the valve, the disease is associated with a very high mortality rate (50 to 60% at one year) beyond the onset of symptoms. The goal of the percutaneous valve is to bring a less invasive therapeutic solution for these patients.

The Cribier-Edwards Percutaneous valve (Edwards Lifesciences, Irvine, Cal, USA) is a bioprosthesis made of three leaflets of equine pericardium sutured to a balloon expandable stainless steel stent. After balloon predilatation of the native valve, this bioprosthesis is crimped over a balloon catheter, and advanced over a stiff guidewire through the vessels (either from the femoral vein –antegrade/transseptal approach- or the femoral artery –retrograde approach-) up to the diseased fibro-calcific native aortic valve, using regular cardiac catheterization techniques. The bioprosthesis is then released by balloon inflation at mid-part of the native valve. In our institution, the technique is performed under local anesthesia and light sedation.


In our experience, the procedure (which first case was performed in April 2002) remains under investigation and implantations are strictly restricted to compassionate cases in patients who have been formally declined by two cardiac surgeons due to severe associated comorbidities. We have enrolled 40 patients to date in two single centre feasibility studies (the I-REVIVE and the RECAST studies). Three patients have now reached two years of follow-up. The valve performance has been excellent and there has not been a single case of valve failure when the valve was successfully placed (80% of the cases). High mortality during follow-up has been related to non valvular causes, mainly the evolution of life-threatening comorbidities.

Challenges remain as the procedure is complex when performed via the antegrade/transseptal route, whereas the less demanding retrograde route has been frequently associated with failures in crossing the native valve. Also, paravalvular leaks can occur (moderate to severe in 25%), which is undesirable despite not being a clinical issue. One reason for the leak has been to have a single valve size (23mm in diameter), too small for some patients.

Two most recent developments relate to a custom retrograde delivery system, as well as a larger 26mm size valve. Dr John Webb (Vancouver, Canada) is the only physician approved yet for investigating these new iterations. He has successfully performed a number of cases using the custom retrograde delivery system and the 26mm valve. The retrograde route is much simpler and can be performed in about one hour. The rate and severity of paravalvular leak has dramatically decreased with the use of the 26mm valve.

Two multicentre studies have just begun enrollment in Europe (REVIVE trial) and the US (REVIVAL trial) that will help to determine the future of this revolutionary and promising interventional cardiology procedure.

Gina Dellios | EurekAlert!
Further information:
http://www.escardio.org

More articles from Health and Medicine:

nachricht Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>