Vascular prosthesis and methods of use
An implantable vascular prosthesis is provided for use in a wide range of applications wherein at least first and second helical sections having alternating directions of rotation are coupled to one another. The prosthesis is configured to conform to a vessel wall without substantially remodeling the vessel, and permits accurate deployment in a vessel without shifting or foreshortening.
1. A vascular prosthesis for implantation in a body vessel having a vessel wall, the vascular prosthesis comprising:
an alternating helical section placeable in a contracted state, suitable for transluminal insertion into the body vessel, and in an expanded state,
the alternating helical section having a flat ribbon-like helical structure with a width and thickness, the width being substantially greater than the thickness,
the alternating helical section comprising first, second and third helical portions, the helical portions arranged in series with each helical portion having proximal and distal ends, wherein the first and the third helical portions have a direction of rotation about a longitudinal axis of the prosthesis opposite to that of the second helical portion,
the distal end of the first helical portion connected directly to the proximal end of the second helical portion at a first apex, the distal end of the second helical portion connected directly to the proximal end of the third helical portion at a second apex, the first helical portion being connected to the second helical portion only at the first apex,
the distal ends of the first and second helical portions and the proximal ends of the second and third helical portions having converging sides, each of the first and second apices also comprising converging sides terminating at a narrowed tip, and
the entire first and second helical portions have different lengths to place the first and second apices at substantially different circumferential positions when in the expanded state, whereby a mechanical characteristic of the vascular prosthesis can be affected by said different positions.
2. The vascular prosthesis of claim 1 , wherein the alternating helical section includes an even number of helical portions having a first direction of rotation and an odd number of helical portions having a second direction of rotation, wherein the connected helical portions define an even number of apices.
3. The vascular prosthesis of claim 1 , wherein the first and second helical portions have different pitches.
4. The vascular prosthesis of claim 1 , wherein the alternating helical section comprises a free end configured to be located radially outward of the adjacent helical portion when the vascular prosthesis is in the contracted state.
5. The vascular prosthesis of claim 1 , wherein the alternating helical section comprises a free end configured to be located radially inward of the adjacent helical portion when the vascular prosthesis is in the contracted state.
6. The vascular prosthesis of claim 1 , wherein at least one helical portion is a helical mesh.
7. The vascular prosthesis of claim 1 , further comprising a therapeutic agent disposed on a surface of the alternating helical section.
8. The vascular prosthesis of claim 1 , further comprising a polymer disposed on a surface of the alternating helical section.
9. The vascular prosthesis of claim 8 , wherein the polymer is disposed on a surface of the alternating helical section and configured to be a stent graft.
10. The vascular prosthesis of claim 8 , wherein the polymer is configured to elute a therapeutic agent.
11. The vascular prosthesis of claim 1 , further comprising a radially expanding anchor section joined to a first end of the alternating helical section.
12. The vascular prosthesis of claim 11 , wherein the alternating helical section and the first anchor section each are capable of assuming a contracted state suitable for transluminal insertion into the body vessel and a deployed state wherein the helical section and first anchor section are configured to engage the vessel wall.
13. The vascular prosthesis of claim 1 , wherein the alternating helical section comprises a shape memory material.
14. The vascular prosthesis of claim 13 , wherein the shape memory material is a nickel titanium alloy.
15. The vascular prosthesis of claim 11 , wherein the alternating helical section and the anchor section are separately formed and then coupled together.
16. The vascular prosthesis of claim 11 , wherein the alternating helical section and the anchor section are integrally formed.
17. The vascular prosthesis of claim 1 , wherein the mechanical characteristic that can be affected by said different positions comprises at least one of flexibility, gap control, and compression resistance.
18. A vascular prosthesis for implantation in a body vessel having a vessel wall, the vascular prosthesis comprising:
an alternating helical section placeable in a contracted state, suitable for transluminal insertion into the body vessel, and in an expanded state,
the alternating helical section having a flat ribbon-like helical structure with a width and thickness, the width being substantially greater than the thickness,
the alternating helical section comprising first, second and third helical portions, the helical portions arranged in series with each helical portion having proximal and distal ends, wherein the first and the third helical portions have a direction of rotation about a longitudinal axis of the prosthesis opposite to that of the second helical portion,
the distal end of the first helical portion connected directly to the proximal end of the second helical portion at a first apex, the distal end of the second helical portion connected directly to the proximal end of the third helical portion at a second apex, the first helical portion being connected to the second helical portion only at the first apex,
the distal ends of the first and second helical portions and the proximal ends of the second and third helical portions having converging sides, each of the first and second apices also comprising converging sides terminating at a narrowed tip, and
means for placing the first and second apices at substantially different circumferential positions when in the expanded state, whereby a mechanical characteristic of the vascular prosthesis can be affected by said different positions, the mechanical characteristic comprising at least one of flexibility, gap control, and compression resistance.