Methods of conditioning sheet bioprosthetic tissue

• US 8,846,390 B2
• Filed: 03/23/2011
• Issued: 09/30/2014
• Est. Priority Date: 03/23/2010
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Dove, Jeffrey S., Tian, Bin, Schneider, Ralph, Cohen, Jeffrey S., Jankovic, Ivan, Migliazza, John F., Wright, Gregory A., Young, James M., Campbell, Louis A.
• Primary Examiner(s): EPPS -SMITH, JANET L
• Application Number:
  US13/069,827
• Publication Number:
  US 20110238167A1
• Time in Patent Office: 1,287 Days
• Field of Search: 435/325, 606/14, 600/36, 623/2.13
• US Class Current: 435/325
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61F 2/02 Prostheses implantable into the body closure means for urethra or rectum or for artificial body openings therefor A61F2/0004
• CPC Class Codes: A61F 2/24 Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
• CPC Class Codes: A61F 2/2409 Support rings therefor, e.g. for connecting valves to tissue annuloplasty rings A61F2/2442
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2/2418 Scaffolds therefor, e.g. support stents
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61L 2300/60 characterised by a special physical form
• CPC Class Codes: A61L 2430/20 for reconstruction of the heart, e.g. heart valves
• CPC Class Codes: A61L 27/3604 characterised by the human or animal origin of the biological material, e.g. hair, fascia, fish scales, silk, shellac, pericardium, pleura, renal tissue, amniotic membrane, parenchymal tissue, fetal tissue, muscle tissue, fat tissue, enamel
• CPC Class Codes: A61L 27/3625 Vascular tissue, e.g. heart valves
• CPC Class Codes: A61L 27/3691 characterised by physical conditions of the treatment, e.g. applying a compressive force to the composition, pressure cycles, ultrasonic/sonication or microwave treatment, lyophilisation
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: B65B 55/18 by liquids or gases B65B55/14 takes precedence
• CPC Class Codes: B65B 63/02 for compressing or compacting articles or materials prior to wrapping or insertion in containers or receptacles

Abstract

Methods for the conditioning of bioprosthetic material employ bovine pericardial membrane. A laser directed at the fibrous surface of the membrane and moved relative thereto reduces the thickness of the membrane to a specific uniform thickness and smoothes the surface. The wavelength, power and pulse rate of the laser are selected which will smooth the fibrous surface as well as ablate the surface to the appropriate thickness. Alternatively, a dermatome is used to remove a layer of material from the fibrous surface of the membrane. Thinning may also employ compression. Stepwise compression with cross-linking to stabilize the membrane is used to avoid damaging the membrane through inelastic compression. Rather, the membrane is bound in the elastic compressed state through addition cross-linking. The foregoing several thinning techniques may be employed together to achieve strong thin membranes. The finally thinned membrane may then be treated by capping of calcification nucleation sites and borohydride reduction. The leaflets may be formed to have more than one region of uniform thickness, such as a thicker peripheral sewing region.

Claims

1. A method for preparing bioprosthetic tissue membrane material, comprising:

selecting a collagenous tissue membrane having opposite sides and a non-uniform thickness;

cross-linking the collagenous tissue membrane;

removing a layer of collagenous tissue from the collagenous tissue membrane from at least one side of the membrane to reduce the thickness of the collagenous tissue membrane;

compressing the collagenous tissue membrane after the removing while also cross-linking the membrane such that the collagenous tissue membrane has a substantially uniform thickness after the compressing; and

subjecting the collagenous tissue membrane to a glycerin-based treatment solution.

2. The method of claim 1, wherein the collagenous tissue membrane is bovine pericardial membrane.

3. The method of claim 1, further comprising treating the collagenous tissue membrane with a capping agent and a reducing agent.

4. The method of claim 1, wherein the collagenous tissue membrane before the removing and the compressing has a thickness of 300-700 microns, and the final thickness of at least a portion of the collagenous tissue membrane after the removing and the compressing is less than 300 microns.

5. The method of claim 1, wherein the step of removing is accomplished by shearing or milling with a mechanical device.

6. The method of claim 1, wherein the step of removing is accomplished by ablating with an ultra-short-pulsed laser in the Femtosecond range.

7. The method of claim 1, further comprising removing an additional layer of collagenous tissue from the collagenous tissue membrane after the glycerin-based treatment solution to reduce the thickness in a portion thereof to a greater degree than the remainder of the collagenous tissue membrane.

8. The method of claim 1, wherein the collagenous tissue membrane has a fibrous side and a smooth side, and the removing is performed on the fibrous side to smooth the fibrous side.

9. A method for preparing a heart valve leaflet from bioprosthetic tissue membrane material, comprising:

selecting a collagenous tissue membrane having a fibrous side and a smooth side;

cross-linking the collagenous tissue membrane;

removing a layer of collagenous tissue from the fibrous side of the membrane by shearing or milling with a mechanical device to smooth the fibrous side; and

forming a heart valve leaflet with the collagenous tissue membrane.

10. The method of claim 9, further comprising compressing the collagenous tissue membrane to reduce a membrane thickness while also cross-linking the membrane.

11. The method of claim 9, wherein the collagenous tissue membrane is bovine pericardial membrane.

12. The method of claim 9, wherein the collagenous tissue membrane is porcine pericardial membrane.

13. The method of claim 9, further comprising subjecting the collagenous membrane to a glycerin-based treatment solution.

14. The method of claim 13, further comprising treating the collagenous tissue membrane with a capping agent and a reducing agent.

15. The method of claim 9, wherein the collagenous tissue membrane before the removing has a thickness of 300-700 microns, and the final thickness of at least a portion of the membrane after the removing is less than 300 microns.

16. The method of claim 9, further comprising compressing the collagenous tissue membrane to reduce a membrane thickness while also cross-linking the membrane.

17. A method for fabricating a heart valve leaflet, comprising:

selecting a collagenous tissue membrane having a fibrous side and a smooth side;

removing a layer of collagenous tissue from the fibrous side of the collagenous tissue membrane by ablating with an ultra-short-pulsed laser in the Femtosecond range to smooth the fibrous side;

cross-linking the collagenous tissue membrane;

compressing the collagenous tissue membrane to reduce a membrane thickness while also cross-linking the collagenous tissue membrane;

subjecting the collagenous tissue membrane to a glycerin-based treatment solution; and

forming a heart valve leaflet from the collagenous tissue membrane to have an arcuate cusp edge and a free edge opposite the cusp edge.

18. The method of claim 17, further comprising removing a further layer of collagenous tissue in a central region of the heart valve leaflet by ablating with an ultra-short-pulsed laser in the Femtosecond range to reduce the thickness.

19. The method of claim 18, wherein after the step of removing the thickness at the cusp edge is between 300-700 microns, and the thickness in the central region is less than 300 microns.

20. The method of claim 18, wherein the step of removing also reduces the thickness in the central region to a greater degree than at the free edge.

21. The method of claim 17, further comprising treating the collagenous tissue membrane with a capping agent and a reducing agent.