Value prosthesis for implantation in body channels
A valve prosthesis which is especially useful in the case of aortic stenosis and capable of resisting the powerful recoil force and to stand the forceful balloon inflation performed to deploy the valve and to embed it in the aortic annulus, comprises a collapsible valvular structure and an expandable frame on which said valvular structure is mounted. The valvular structure is composed of physiologically compatible valvular tissue that is sufficiently supple and resistant to allow the valvular structure to be deformed from a closed state to an opened state. The valvular tissue forms a continuous surface and is provided with strut members that create stiffened zones which induce the valvular structure to follow a patterned movement in its expansion to its opened state and in its turning back to its closed state.
1. A method of implanting a valve prosthesis to treat valvular aortic stenosis, which comprises the steps of:
(a) advancing a first balloon dilatation catheter having distal and proximal ends and having a deflated first dilatation balloon adjacent the catheter distal end into a patient's vasculature to position said first dilatation balloon within a native stenotic aortic valve and annulus;
(b) inflating said first dilatation balloon to dilate the stenotic aortic valve;
(c) deflating said first dilatation balloon and withdrawing said deflated balloon in the proximal direction;
(d) advancing a second dilatation catheter having distal and proximal ends and having a second deflated dilatation balloon adjacent the catheter distal end, wherein said second balloon has a valve prosthesis arranged circumferentially around said second dilatation balloon, into the patient's vasculature to position said second dilatation balloon and said valve prosthesis adjacent to the previously dilated native stenotic aortic valve;
(e) inflating said second dilatation balloon to cause said valve prosthesis to adhere to said native aortic valve and annulus; and
(f) deflating said second dilatation balloon and withdrawing said second catheter in the proximal direction.
2. The method of claim 1 , wherein prior to step (a), a guidewire having a distal end is advanced distally into the patient's vasculature until the guidewire distal end is adjacent or distal to the native stenotic aortic valve.
3. The method of claim 2 , wherein in steps (a) and (d) the first and second balloon catheters, respectively, are advanced over the guidewire.
4. The method of claim 1 , wherein in step (b) the first dilatation balloon is inflated to a high pressure.
5. The method of claim 4 , wherein the first dilatation balloon is inflated maximally up to the balloon's bursting point.
6. The method of claim 4 , wherein the inflation lasts only a few seconds.
7. The method of claim 1 , wherein inflating the dilatation balloon in step (b) tests the native stenotic aortic valve for efficacy of the procedure and creates an aperture in the native stenotic aortic valve.
8. The method of claim 1 , wherein in step (e) the second dilatation balloon is inflated to a high pressure.
9. The method of claim 8 , wherein the second dilatation balloon is inflated to a pressure less than the pressure to which the first dilatation balloon is inflated.
10. The method of claim 8 , wherein the inflation lasts only a few seconds.
11. The method of claim 1 , wherein the valve prosthesis needs only a light pressure for its own expansion.
12. The method of claim 1 , wherein the valve prosthesis comprises:
a collapsible, elastic valve member comprised of physiologically acceptable material,
an elastic stent member in which said valve member is mounted, said stent member having internal and external surfaces, and
a support coupled to the valve member and positioned between the valve member and the stent member,
wherein said stent member forms a continuous surface and comprises strut members that provide a structure sufficiently rigid to prevent eversion, wherein the support extends from the internal surface of the stent member to the external surface of the stent member, and wherein the stent member has sufficient radial and longitudinal rigidity to withstand the radial force necessary for implantation, to resist aortic recoil forces, and to provide long-term support to the valve structure.