Stent for blood flow improvement

• US 20070162104A1
• Filed: 02/20/2007
• Published: 07/12/2007
• Est. Priority Date: 12/12/2000
• Status: Active Grant

• Current Assignee: Cardiatis S.A.
• Original Assignee: Cardiatis S.A.
• Inventors: Frid, Noureddine
• Granted Patent: US 8,192,484 B2
• Time in Patent Office: Days
• US Class Current: 623/1.150
• CPC Class Codes: A61F 2/856 Single tubular stent with a side portal passage
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/0086 for preferentially controlling or promoting the growth of specific types of cells or tissues
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: Y10T 29/49 Method of mechanical manufacture

Abstract

Luminal endoprosthesis formed of a multi-layer braided framework. The framework is devoid of any cover layer, and formed of a plurality of stabilized layers of biocompatible metal wires which are interlaced, forming a lattice, a plurality of wires of a given layer being integrated in the lattice of the adjacent layers. The mechanical characteristics of an outermost layer is so that when in place, the layer applies against a vessel wall, the other layers extending substantially along cylindrical surfaces distinct from the outermost layer so as to form a multi-layer mat which affects the haemodynamic of a flow of blood passing along or through this mat and preventing a growing of plaque.

Claims

1. Luminal endoprosthesis consisting of a braided framework, wherein the framework, devoid of any cover layer, comprises a plurality of stabilized layers of biocompatible metal wires which are interlaced, forming a lattice, a plurality of wires of a given layer being integrated in the lattice of at least one of the adjacent layers, the mechanical characteristics of the layers being so that when in place, an outermost layer applies against a vessel wall, the other layers extending substantially along cylindrical surfaces distinct from the outermost layer so as to form a multi-layer wall so designed that its porosity locally affects the haemodynamic of a flow of blood passing along or through said wall, transforming the haemodynamic convection of the flow passing along said wall into a laminated diffusion flow passing through said wall.

2. Luminal endoprosthesis according to claim 1, wherein the wires of the various braided layers are arranged so that meshes, as seen from a plane normal to a longitudinal axis of the endoprosthesis, present a regular size.

3. Luminal endoprosthesis according to claim 1, wherein the superponed layers of the endoprosthesis are designed and alined so that the resulting porosity of the layers, when placed in front of a collateral opening up in the wall of a vessel, provoke a pressure drop laminating the flow of blood in the collateral and avoiding the clogging of the layers extending in front of the mouth of the collateral.

4. Luminal endoprosthesis according to claim 1, wherein the material of the wires is chosen from among the following materials [stainless steel, Phynox®

, Elgiloy®

, titanium and its alloys, Nitinol].

5. Luminal endoprosthesis according to claim 1, wherein the framework comprises wires of different metals.

6. Luminal endoprosthesis according to claim 2, wherein the framework comprises wires of different metals.

7. Luminal endoprosthesis according to claim 1, wherein the thickness of the wires lies at least within a range of between 25 and 80 micrometres.

8. Luminal endoprosthesis according to claim 3, wherein the thickness of the wires lies at least within a range of between 25 and 80 micrometers.

9. Luminal endoprosthesis consisting of a braided framework, wherein the framework, devoid of any cover layer, comprises a plurality of stabilized layers of biocompatible metal wires which are interlaced, forming a lattice, a plurality of wires of a given layer being integrated in the lattice of at least one of the adjacent layers, the mechanical characteristics of an outermost layer being so that when in place, said layer apply against a vessel wall, the other layers extending substantially along cylindrical surfaces distinct from the outermost layer so as to form a multi-layer mat so designed that the combined effect of the various layers locally affects the haemodynamic of a flow of blood passing along said mat, the flow of blood being derivated towards an inner face of an innermost layer and provoking a lowering of the pressure exerted on the vessel wall, preventing a growing of plaque along said vessel wall and promoting the growth of a new layer of endothelial cells.

10. Luminal endoprosthesis according to claim 9, wherein the wires of the various braided layers are arranged so that meshes, as seen from a plane normal to a longitudinal axis of the endoprosthesis, present a regular size.

11. Luminal endoprosthesis according to claim 9, wherein the superponed layers of the endoprosthesis are designed and alined so that the resulting porosity of the layers, when placed in front of a collateral opening up in the wall of a vessel, provoke a pressure drop laminating the flow of blood in the collateral and avoiding the clogging of the layers extending in front of the mouth of the collateral.

12. A method for manufacturing a luminal endoprosthesis comprising the following operations:

Selecting at least one bio-compatible metal;

Drawing out said at least one metal into wires;

Choosing braiding parameters so that the final braid will be given a definite dynamic porosity;

Braiding said wires so as to form a multi-layer stent, the wires of each layer being interlaced with the wires of each of the other layers;

Stabilizing the form of the stent and the relative position of the wires of each layers by submitting it to a heat treatment;

13. A method according to claim 12, comprising the following operation:

submitting the framework after braiding to a thermical treatment triggering a memory phase transition.