Method for producing an aortic or mitral heart valve prosthesis and resulting aortic or mitral heart valve

• US 20050177227A1
• Filed: 04/22/2003
• Published: 08/11/2005
• Est. Priority Date: 04/23/2002
• Status: Active Grant

• Current Assignee: Universite De Strasbourg (Financière Meeschaert SA), Les Hopitaux Universitaires De Strasbourg, Universite De Haute Alsace
• Original Assignee: Universite De Strasbourg (Financière Meeschaert SA), Les Hopitaux Universitaires De Strasbourg, Universite De Haute Alsace
• Inventors: Heim, Frederic, Durand, Bernard, Chakfe, Nabil, Kretz, Jean-Georges
• Granted Patent: US 8,043,551 B2
• Time in Patent Office: Days
• US Class Current: 623/2.120
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/26 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene

Abstract

A method for producing an aortic or mitral heart valve prosthesis and the resulting aortic or mitral heart valve. The method is characterized in that it essentially consists in producing the prosthesis by shaping a textile material. The invention is more particularly applicable in the field of medicine, in particular repair surgery, and especially in heart surgery, more particularly heart prostheses.

Claims

1-27. -27. (canceled)

28. Process for the production of an aortic or mitral cardiac valve prosthesis, characterized in that it consists essentially in making said prosthesis by shaping a textile material, in particular by shaping flaps (2) in a textile membrane of the type selected from the group formed by the following assembly modes:

woven, non-woven in the form of assembled fibers, non-woven obtained by autofibrillation of a membrane by drawing and knitting, the shaping of the flaps (2) being carried out in a tubular element (1) of a textile membrane, by a concentric sheathing of three flaps (2) of identical surfaces on a shaping member (3) reproducing the geometry of the flaps of a cardiac valve in the closed artery position, with preliminary cutting out of said tubular element (1) into cylindrical segments (4) extending between the radii of said flaps (2), said tubular element (1) being held firmly above segments (4) forming the object of preliminary cutting out and being adapted to slide over the lower portion of the forming member (3) reproducing the geometry of the flaps (2) to form said flaps (2) without plastic elongation deformation of the fibers but with reduced deformation of the membrane or the meshes of the cloth, in providing the cutout edges of the flaps (2) with a protection and junction means between flaps in the closed position of the valve, then in carrying out if desired a thermofixation of the membranes and of the cloth thus deformed by passage through an oven at a temperature slightly greater than the vitreous transition temperature and finally in removing the valve prosthesis (1) obtained from the shaping member (3), after eventual cooling.

29. Process according to claim 28, characterized in that the preliminary cutting out of the tubular element (1) into cylindrical segments (4) extending between the radii of said flaps (2) is carried out, for each flap (2), by means of a cutting device sectioning the tubular element of textile material (1) over all the length of the segment with the positioning of said device slightly in front of the beginning of the simultaneous concentric sheathing of the three flaps (2) on the shaping member (3).

30. Process according to claim 28, characterized in that the tubular element of textile material is blocked at points, at three regular intervals of 120°

from the lower portion of the sheathing support (3) by means of blocking means (5) such as retention points, these blocking means (5) extending in prolongation of holding rods connecting the upper and lower portions of said sheathing support (3).

31. Process according to claim 28, characterized in that at the height of the holding rods of the sheathing support, the tubular element of textile material is not cut out, such that the sheathed piece obtained has a lower portion provided with flaps (2) and prolonged downwardly by a cylindrical skirt, said cylindrical skirt with the flaps (2) being connected by wall elements of relatively slight width to an upper cylindrical ring, the width of these wall elements being substantially equal to the diameter or to the width of the holding rods connecting the upper and lower portions of the sheathing support (3).

32. Process according to claim 28, characterized in that the fiber structure constituting the tubular element of textile material is constituted, either in the form of a longitudinal strip closed on itself along a longitudinal generatrix by stitching, or in the form of a continuous tube without stitching.

33. Process according to claim 28, characterized in that the emplacement on the cutoff edges of the flaps (2) of a protection and junction means between the flaps in the closed position of the valve, consists essentially in a treatment of the cutoff portions of each flap (2), namely the radii of junction to the corresponding circular segment, by deposit of a covering material for the cutoff edges, in the form of a pad or the like.

34. Device for carrying out the process according to claim 28, characterized in that the structure of the sheathing support (3) is constituted by a lower cylindrical portion comprising a central molded portion with shapes corresponding to the shape of the flaps (2) to be obtained and by an upper cylindrical portion connected to the lower portion by means of three holding rods extending between themselves at intervals of 120°

and implanted in line with the junction of the radii constituting said flaps (2) with the corresponding angular segment, said upper portion having, in the direction of the lower portion, a perfectly flat surface and an external cutting edge.

35. Device according to claim 34, characterized in that the sheathing support (3) is provided with blocking means (5), such as retaining points, these blocking means (5) extending in prolongation of the holding rods connecting the upper and lower portions of said sheathing support (3).

36. Process according to claim 28, characterized in that the shaping of the flaps (2) by concentric sheathing in a tubular element (1) is replaced by a shaping by weaving in three dimensions of three flaps of identical surface reproducing the geometry of the flaps of a cardiac valve in the position of closure of the artery, this weaving being carried out with filaments of fibers of biocompatible synthetic textile material.

37. Process according to claim 28, characterized in that the shaping of the flaps (2) by concentric sheathing in a tubular element (1) is replaced by a shaping of the flaps (2) by sheathing a textile member disposed flat against the corresponding mold, followed by cutting out by bending of the flaps and securement and if desired the thermofixation of the membrane.

38. Process according to claim 28, characterized in that the shaping of the flaps (2) by concentric sheathing in a tubular element (1) is replaced by a shaping of the flaps (2) by slight preliminary mechanical deformation of the edge zone of a textile membrane in the direction of a corresponding counter-form, then by application, to the deformations, of a heat exchange fluid.

39. Process according to claim 38, characterized in that the heat exchange fluid used can be a gaseous fluid, steam, or a liquid fluid.

40. Process according to claim 38, characterized in that the slight preliminary mechanical deformation is effected by means of a die moving the portion of membranes in the direction of the corresponding recesses of the counter-form, the final deformation and thermofixation being then carried out by circulation of a heat exchange fluid, after withdrawal of the die.

41. Process according to claim 28, characterized in that the shaping of the flaps (2) by concentric sheathing in a tubular element (1) is replaced by shaping by application of the edge zone of a textile membrane against a counter-form by suction through said counter-form, a thermofixation of the obtained flaps being effected by the supply of hot air or gas drawn through the textile membrane into the counter-form.

42. Process according to claim 41, characterized in that, in the case of use of a liquid heat exchange fluid, the latter is projected at a certain pressure against the edge zone of the textile membrane, which then matches the counter-form.

43. Process according to claim 28, characterized in that the shaping of the flaps (2) by concentric sheathing in a tubular element (1) is replaced by an operation of forming carried out only by use of a heat exchange fluid pressing the edge zone of the textile membrane against said counter-form and having a temperature slightly greater than the vitreous transformation temperature of the textile used.

44. Aortic or mitral cardiac valve prosthesis, obtained by carrying out the process according to claim 28, characterized in that it is essentially constituted by a textile material in the form of a textile membrane constituted by fibers of polyester or polytetrafluoroethylene alone or in mixture or else by a membrane autofibrilated by drawing polytetrafluoroethylene and having a filamentary and fibrous structure limiting the concentrations of stress, as well as low rigidity of flexure and a high rigidity in traction.

45. Prosthesis according to claim 44, characterized in that the textile material is provided with a coating of material or inserts of material improving its surface condition or promoting rehabilitation and/or having particular physiological properties.

46. Prosthesis according to claim 44, characterized in that the textile material is provided with a coating or inserts of medical substance that slowly dissolves, for example to avoid the formation of clots or else a colony of endothelial cells.

47. Prosthesis according to claim 44, characterized in that the textile material constituting it is a microporous membrane.

48. Prosthesis obtained by the practice of the process according to claim 28, characterized in that in the case of production of flaps (2) directly in the edge zone of a textile membrane, the free edge of this zone comprises a woven or knit edge avoiding raveling of said edge.

49. Prosthesis obtained by the practice of the process according to claim 28, characterized in that each flap (2) extends over a circular segment having an opening angle of 120°

over its periphery, such that the free edge of each pocket delimited by each flap (2) has a length corresponding to twice the length of the radius of the flap, which is slightly less than that defined by said opening angle over the periphery, which length corresponds to twice the radius multiplied by n and divided by three.