CROSS-REFERENCE TO RELATED APPLICATIONS

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This application is a continuation of PCT/IB2012/000563, filed Mar. 21, 2012, which application claims the benefit of priority of commonly assigned U.S. patent application Ser. No. 61/454,703, filed Mar. 21, 2011, and entitled “Multiple Disk Self-Positioning Apparatus and Method for the Treatment of Valve Dysfunction”.

FIELD OF THE INVENTION

The present invention generally relates to valve implantation and more specifically to the percutaneous replacement of dysfunctional valves.

BACKGROUND OF THE INVENTION

a) Transcatheter Aortic Valve Implantation (TA VI)

In addition to the initial commercially approved devices for transcatheter aortic valve implantation (TAVI) such as the Edwards-Sapien™ THV balloon expandable bovine bioprosthesis (Edwards Lifesciences INC, Irvine, Calif., USA) and the Core Valve ReValving® System (Medtronic Inc., Minneapolis, Minn., USA), nitinol porcine self-expanding bioprosthesis, a number of newer devices have also recently been CE marked for use via the transapical route. These are the Symetis Acurate (Symetis, Lausanne, Switzerland) and the Jena Valve (JenaValve, Munich, Germany) that are described below in the text.

Several valves for TAVI are currently at an early stage of pre-clinical study or clinical evaluation. Referring to Table 1, in general, new valves incorporate features aiming to reduce delivery catheter diameter, facilitate accurate positioning, reduce para-valvular leaks, or allow device retrieval. In the following paragraphs we will describe some of the publicly known programs.

The Direct Flow Medical Aortic Valve, developed by Direct Flow Medical Inc., USA and shown by D in FIG. 1, is a stent-less, non-metallic, expandable device that consists of bovine pericardial leaflets sewed to a Dacron fabric cuff, with an inflatable ring on the aortic side and another on the ventricular side, designed for trans-femoral delivery. Once the valve is positioned, the rings are inflated with saline and contrast until the position and function of the valve has been confirmed. The diluted contrast is then exchanged for an active polymeric medium that, following polymerization, hardens and forms the final support structure.

The Lotus Valve System developed by Boston Scientific Inc., USA, as shown by FIG. 1, is a bioprosthesis consisting of three bovine pericardial leaflets suspended in a self-expanding and self-centering braided nitinol stent frame. It has an active shortening-locking mechanism and an external polyurethane sealing membrane to prevent para-valvular leaks. In the delivery catheter the stent it is in its longitudinal form, with low radial force and small profile. Once the valve has been positioned and the outer catheter is retracted, the prosthesis expands radially, gaining radial force and losing height, effectively locking the valve in place. The valve is designed for trans-femoral delivery.

The Heart Leaflet Technologies (“HLT”) valve, developed by Heart Leaflet Technologies Inc., USA, and as shown by A in FIG. 1, is a porcine pericardial trileaflet valve mounted in a self-inverting nitinol cuff, with 3 nitinol support hoops and with an antireflux collar, designed for trans-femoral delivery.

The JenaClip, developed by Jena Valve Technology GmbH, Munich, Germany and shown by C in FIG. 1, is a bioprosthetic pericardial tissue valve mounted in a self-expanding nitinol stent, as known as the JenaClip, that is built up of 2 layers of “paper clip-like” structures (3 in each layer) that are compressed in a dedicated delivery catheter. It has been designed anatomically to fit in the sinuses of Valsalva with a clip-based anchoring system 20. It is designed for both trans-femoral and trans-apical delivery and recently had CE mark for the transapical route.

The Engager valve, formerly developed by Ventor, recently acquired by Medtronic, Minneapolis, Minn., and shown by H in FIG. 1, is a self-expandable pericardial-tissue prosthesis with a composite nitinol proprietary frame. The outer frame has a crown-shape, with troughs that flare out to anchor the valve in the sinuses. An inner frame has an hourglass shape and is designed to minimize pressure loss at inlet and maximize pressure recovery at outlet, and thereby optimizing fluid dynamics (based on the Venturi effect). This device is specifically dedicated for trans-apical delivery, but more recently a trans-femoral version has been developed.

The AorTx Device, developed by Hansen Medical Inc., Mountain View, Calif. and shown by F in FIG. 1, is a suture-less prosthesis that consists of a pericardial-tissue valve attached to a self-expanding, solid nitinol frame. This frame is folded before deployment. It is repositionable and retrievable. This valve has been designed for both trans-apical and femoral approach through an 18F delivery system. The ATS 3f Series, developed by ATS Medical, Minneapolis, Minn. and shown by E in FIG. 1, is a self-expandable bioprosthesis mounted in a tubular nitinol frame designed for surgical (ATS 3f Enable) and percutaneous (ATS 3f Entrata) deployments. Six sizes are available, from 19 to 29 mm. The Perceval-Percutaneous, developed by the Sorin Group, Milan, Italy and shown by G in FIG. 1 is a self-expandable bovine pericardial valve with a nitinol panel frame matching the anatomy of the aortic root and sinuses of Valsalva. It has a double sheath that provides enhanced sealing and non-expandable support rods.

The Bailey-Palmaz Perc Valve, developed by Advanced Bio Prosthesis Surfaces, Ltd. San Antonio, Tex. (not shown) is a completely mechanical valve consisting of a monolithic structure of nanosythesized nitinol in a self-expanding cage and nitinol leaflets that also has a nitinol membrane at the base of the valve to reduce paravalvular regurgitation. This new nanosynthetic material has improved stress and fracture resistance and has allowed for a device with a smaller profile, which can be delivered through a 1 OF sheath. It is designed to be repositionable and retrievable, and to be delivered by retrograde, antegrade, or transapical approach.

The Paniagua Heart Valve, developed by Endoluminal Technology Research, Miami, Fla. and shown by H in FIG. 1, is a biologic valve having a collapsed profile of 2 mm that must be manually crimped on to a delivery balloon, but that also exists as a self-expanding model. It can be inserted through a 10F to 18F sheath, depending on the mounting frame and the final valve diameter. This valve was designed to be used in any heart valve position.

Symetis Acurate valve (Symetis, Lausanne, Switzerland) is a self-expanding nitinol stent has also recently been CE marked for use via the transapical route. The valve is porcine with the stent allowing anchorage via an upper and lower crown along with 3 stabilization arches in a subcoronary position, believed to be the ‘anatomically correct’ position. It is available in 3 sizes: 23 mm, 25 mm and 27 mm, with the ability to be planted sheathless (28 Fr equivalent). The transfemoral version is currently undergoing pre-clinical studies.

Although these valves may incorporate desirable features, little information is currently available on their efficacy, procedural outcomes, and durability.