Compressed tissue for heart valve leaflets
First Claim
1. A method of making a heart valve, comprising:
- providing a sheet material having a first thickness;
compressing the sheet material into a modified sheet having a second thickness less than the first thickness but with substantially the same absolute tensile strength as the sheet material having the first thickness;
forming heart valve leaflets from the modified sheet.
1 Assignment
0 Petitions
Accused Products
Abstract
A process and system for compressing bioprosthetic tissue for use in medical implants. The process involves placing the tissue between two compressive surfaces and applying a force to reduce any nonuniformity of thickness in the tissue, while at the same time reduce the overall thickness. One particularly useful application is the compression of bioprosthetic sheet during the preparation of heart valve leaflets. Bovine pericardium may be compressed to reduce its thickness by about 50%, and then formed into heart valve leaflets. The thinned leaflets have substantially the same absolute strength as those made from uncompressed tissue, and are particular desirable for use in minimally invasive valves which must be compressed into a small profile. The thin tissue enables a reduction in the overall size of the minimally invasive heart valve for delivery. For instance, rolled MIS valves may be reduced in size to as small as 20 mm in diameter. Desirably, a cross-linking step is combined with the compression step to fix the reduced thickness of the tissue. One apparatus may include porous compression substrates through which a cross-linking solution may diffuse so as to perform the fixation and compression simultaneously.
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Citations
42 Claims
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1. A method of making a heart valve, comprising:
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providing a sheet material having a first thickness;
compressing the sheet material into a modified sheet having a second thickness less than the first thickness but with substantially the same absolute tensile strength as the sheet material having the first thickness;
forming heart valve leaflets from the modified sheet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of preparing bioprosthetic tissue for implantation, comprising:
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providing a sheet of bioprosthetic tissue having a first thickness;
compressing the sheet of bioprosthetic tissue into a modified sheet having a second thickness; and
cross-linking the sheet of bioprosthetic tissue during or shortly after the step of compressing. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A system for preparing a sheet of material for implantation in a human body, comprising:
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a pair of semi-permeable substrates having cooperating surfaces configured to receive a sheet material therebetween, the cooperating surfaces having similar shapes so that the surfaces sandwich the sheet material therebetween;
means for compressing the sheet material between the cooperating surfaces to form a modified sheet of reduced thickness;
a source of cross-linking solution; and
means for contacting the modified sheet with the cross-linking solution. - View Dependent Claims (29, 30, 31, 32, 33, 34)
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35. A heart valve comprising:
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a structural component; and
a plurality of cross-linked bioprosthetic tissue leaflets attached to the structural component, the leaflets having been compressed during or just before cross-linking to reduce their thickness. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42)
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Specification