Methods of implanting a prosthetic heart valve within a native heart valve
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 prosthetic heart valve in a patient, comprising:
providing a two-part heart valve, each part being expandable from a compressed state, a first part comprising an external scaffolding frame expandable into a substantially cylindrical shape having an interior surface defining an opening, and a second part comprising a collapsible valvular structure fastened within an internal frame, the valvular structure comprising valve leaflets formed of a biological material;
delivering the external scaffolding frame in its compressed state to an annulus of a native semi-lunar heart valve in a human heart;
expanding the external scaffolding frame into an expanded state to secure the external scaffolding frame within the annulus of the native semi-lunar heart valve;
delivering the second part to within the opening of the expanded external scaffolding frame; and
expanding the internal frame against the interior surface of the external scaffolding frame such that the internal frame is fixed to the external scaffolding frame.
2. The method of claim 1 , wherein delivering the external scaffolding frame to the annulus includes advancing the external scaffolding frame via a catheter introduced into a femoral artery.
3. The method of claim 2 , further including gaining access to the femoral artery using an arterial introducer having a size of 18 F (5.7 mm) or less.
4. The method of claim 1 , wherein the external scaffolding frame is balloon-expandable.
5. The method of claim 1 , wherein both the first and second parts are expanded using separate balloons.
6. The method of claim 5 , wherein both balloons for expanding the first and second parts are located on a single catheter.
7. A method of implanting a prosthetic heart valve within a native aortic valve, comprising:
inflating a balloon to dilate the native aortic valve;
delivering a balloon-expandable external scaffolding stent in a compressed state to an annulus of the native aortic valve, the external scaffolding stent comprising a grate shaped frame forming a substantially cylindrical structure having an interior surface defining an opening;
expanding the external scaffolding stent into an expanded state within the dilated native aortic valve for contacting the leaflets of the native aortic valve and maintaining the native aortic valve in a dilated condition;
delivering a collapsible valvular structure fastened within an internal stent to a location within the expanded external scaffolding stent, the valvular structure comprising valve leaflets formed of a biological material; and
expanding the internal stent against the interior surface of the external scaffolding stent to form the prosthetic heart valve, wherein the internal stent is fixed to the external scaffolding stent.
8. The method of claim 7 , wherein delivering the external scaffolding stent includes advancing the external scaffolding stent via a catheter introduced into a femoral artery.
9. The method of claim 7 , wherein both the external scaffolding stent and valvular structure are expanded using separate balloons.
10. The method of claim 9 , wherein the external scaffolding stent is stronger than the internal stent such that a higher balloon pressure is required to expand the external scaffolding stent than the internal stent.
11. A method of treating aortic stenosis in a human heart, comprising:
inserting a balloon catheter through an opening in a femoral artery;
percutaneously advancing the balloon catheter through an aorta in a retrograde direction to a location within a native aortic valve;
inflating a balloon disposed on the distal end portion of the balloon catheter to dilate stenosed leaflets of the native aortic valve;
deflating the balloon and withdrawing the balloon catheter from the native aortic valve;
inserting a delivery catheter through the opening in the femoral artery, the delivery catheter having a prosthetic heart valve disposed along a distal end portion thereof;
percutaneously advancing the delivery catheter through the aorta in the retrograde direction until the prosthetic heart valve is located within the native aortic valve; and
radially expanding the prosthetic heart valve such that the prosthetic heart valve contacts the stenosed leaflets of the native aortic valve;
wherein the prosthetic heart valve comprises a collapsible support structure and a collapsible valvular structure coupled to the support structure, the valvular structure comprising leaflets formed of a biological material for occluding blood flow in one direction, the prosthetic heart valve further comprising an internal cover extending at least from an inlet end of the support structure to the valvular structure, the internal cover configured for preventing regurgitation through the support structure after the prosthetic heart valve is radially expanded within the native aortic valve.
12. The method of claim 11 , wherein the support structure comprises a stent and the valvular structure is sutured to the stent.
13. The method of claim 12 , wherein the valvular structure comprises tissue from a pig heart.
14. The method of claim 12 , wherein the valvular structure comprises bovine pericardium.
15. The method of claim 12 , wherein the support structure is a stent and the internal cover is attached to the stent.
16. The method of claim 15 , wherein the internal cover and the valvular structure are integrally attached.
17. The method of claim 16 , wherein the internal cover and the valvular structure are formed of the same biological material.
18. The method of claim 17 , wherein the biological material is pericardial tissue.
19. The method of claim 18 , wherein the internal cover and the valvular structure are sutured to the stent.
20. The method of claim 11 , wherein the internal cover extends only from the inlet end of the support structure to the valvular structure.
21. The method of claim 11 , wherein the collapsible support structure is made of a metallic material.
22. The method of claim 21 , wherein the metallic material forms a grate type structure.
23. The method of claim 11 , wherein the collapsible support structure has a concave profile.
24. The method of claim 11 , wherein the prosthetic heart valve is radially expanded by inflating a balloon within the prosthetic heart valve.
25. A method of treating aortic stenosis in a human heart, comprising:
inserting a balloon catheter through an opening in a femoral artery;
percutaneously advancing the balloon catheter through an aorta in a retrograde direction to a location within a native aortic valve;
inflating a balloon disposed on the distal end portion of the balloon catheter to dilate stenosed leaflets of the native aortic valve;
deflating the balloon and withdrawing the balloon catheter from the native aortic valve;
inserting a delivery catheter through the opening in the femoral artery, the delivery catheter having a prosthetic heart valve disposed along a distal end portion thereof;
percutaneously advancing the delivery catheter through the aorta in the retrograde direction until the prosthetic heart valve is located within the native aortic valve; and
radially expanding the prosthetic heart valve such that the prosthetic heart valve contacts the stenosed leaflets of the native aortic valve;
wherein the prosthetic heart valve comprises a collapsible metallic grate type stent and a collapsible valvular structure coupled to and located within the stent, the valvular structure comprising leaflets formed of a biological material for occluding blood flow in one direction, the prosthetic heart valve further comprising an internal cover attached to an interior surface of the stent and extending from the valvular structure toward an inlet end of the stent for preventing passage of blood through spaces between bars of the stent along a lower part of the stent while allowing blood to pass through spaces between bars of the stent along an upper part of the stent after the prosthetic heart valve is radially expanded within the native aortic valve.