Self-Sealing Ptfe Graft with Kink Resistance

• US 20080027534A1
• Filed: 08/30/2005
• Published: 01/31/2008
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Pathak, Chandrashekhar, Brown, Fitzroy, Cole, Heidi, Shahriari, Kereshmeh, Bogert, David, Elton, Richard, Edwin, Tarun, Abbott, Jamie
• Granted Patent: US 8,313,524 B2
• Time in Patent Office: Days
• US Class Current: 623/1.44
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/94 Stents retaining their form, i.e. not being deformable, after placement in the predetermined place
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2250/0069 Sealing means
• CPC Class Codes: A61L 2300/44 Radioisotopes, radionuclides
• CPC Class Codes: A61L 2300/442 Colorants, dyes
• CPC Class Codes: A61L 2420/08 Coatings comprising two or more layers
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61M 1/3655 Arterio-venous shunts or fistulae
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A self-sealing vascular graft, including a substrate with a sealant layer and several optional additional layers, is described. The substrate can be ePTFE and the material used for the sealant and additional layers can be polyurethane. The sealant layer and additional layers may include one or more base layers, one or more foam layers, beading of different sizes and shapes, and ePTFE tape. A flared cuff may be integral to one or both ends of the substrate or may be attached to one or both ends. Various methods of making a self-sealing vascular graft are also described, including methods of disposition, methods of forming, methods of bonding and methods of attaching.

Claims

1. A self-sealing vascular graft, comprising:

a generally tubular ePTFE substrate having a first surface and a second surface spaced from the first surface, wherein the ePTFE substrate is selected from the group consisting of a high porosity graft, a thin-wall graft and combinations thereof; and

a layer of sealant disposed over one of the first and second surfaces of the substrate.

2. A self-sealing vascular graft, comprising:

a tubular ePTFE substrate, wherein the ePTFE substrate is either a high-porosity graft, a thin-wall graft or a combination thereof; and

a layer of sealant disposed over at least a portion of the substrate.

3. A graft for implantation as an AV fistula, comprising:

a tubular ePTFE substrate; and

a layer of sealant disposed over at least a portion of the substrate, wherein the sealant layer has a plurality of grooved sections spaced apart along the length thereof.

4-35. -35. (canceled)

36. A method of forming a vascular graft, comprising:

providing an ePTFE substrate;

applying a first layer of polyurethane over a length of the substrate;

longitudinally compressing the substrate;

applying a second layer of polyurethane over the first layer of polyurethane;

wrapping a layer of ePTFE tape around the polyurethane coated substrate, the ePTFE tape passing first through a solution such that an amount of solution is applied to the ePTFE tape.

37. A self-sealing vascular graft, comprising:

a generally tubular ePTFE substrate having a first surface and a second surface spaced from the first surface; and

a layer of sealant disposed over one of the first and second surfaces, the sealant comprising a polymeric material resistant to plastic deformation upon insertion of a puncture member through the sealant layer.

38. The self-sealing vascular graft according to claim 37, wherein the sealant comprises a material selected from the group consisting essentially of aromatic polycarbonate polyurethanes, polyetherurethanes, polyether/polyamide block copolymers, polydimethylsiloxane elastomers, or other silicone elastomers and combinations thereof.

39. The self-sealing vascular graft according to claim 37, wherein the sealant comprises a heat-treated aromatic polycarbonate polyurethane.

40. The self-sealing vascular graft according to claim 37, wherein the polyurethane includes a weight-average molecular weight (MW) of about 50,000 g/mole.

41. The self-sealing vascular graft according to claim 37, wherein the sealant comprises particles of a material selected from the group consisting essentially of polyester, collagen, thrombin, or fibrinogen and combinations thereof.

43. The self-sealing vascular graft according to claim 37, wherein the ePTFE substrate is selected from the group consisting of a high porosity graft, a thin-wall graft and combinations thereof.

62. The self-sealing vascular graft according to claim 37, further comprising a bioactive agent incorporated into at least one of the substrate, sealant layer, foam layer, and outer layer.

63. The self-sealing vascular graft according to claim 62, wherein the bioactive agent is selected from the group consisting essentially of carbon particles, silver particles, graphite particles, antibiotics, macrolide antibiotics, steroidal agents, anti-inflammation agents, antineoplastic agents, antifungals, antivirals, antibodies, genetic sequence agents, growth factors inhibitors, angiogenesis, anti-angiogenesis, proteinase inhibitors, antiproliferative compounds, or cell cycle modulators and combinations thereof.

64. The self-sealing vascular graft according to claim 37, wherein a generally tubular end of the graft is coupled to a flared end of a prosthetic cuff graft.

65. The self-sealing vascular graft according to claim 64, wherein the generally tubular end is threaded to a generally tubular portion of the prosthetic cuff graft.

66. The self-sealing vascular graft according to claim 64, wherein the generally tubular end is bonded to the generally tubular portion of the prosthetic cuff graft.

42. (canceled)

44-61. -61. (canceled)

67. A method of making a self-sealing vascular cuff graft, comprising:

positioning a neck portion of a cuff over a first end of an ePTFE substrate;

dipping the substrate into a sealant material from a second end thereof to the neck portion of the cuff; and

dipping the substrate and neck portion of the cuff in the sealant material.

68. The method according to claim 67, further comprising wrapping a beading about the substrate and neck portion and dipping the beaded substrate and neck portion into the sealant material.

69-96. -96. (canceled)

97. A method of making a kink resistant self-sealing vascular graft, comprising:

providing a generally tubular ePTFE substrate;

disposing a layer of sealant over at least a portion of an outer surface of the substrate;

positioning a beading over at least a portion of the sealant layer; and

coupling a cuff graft to the vascular graft.

98. The method according to claim 97, wherein the coupling comprises positioning a tubular portion of the cuff graft over a first end of the vascular graft so that a proximal end of the tubular portion lies adjacent an end of the beading, and rotating the tubular portion to move the cuff graft in a proximal direction over a portion of the beading.

99. The method according to claim 97, further comprising bonding the cuff graft to the vascular graft by applying an adhesive to the inner surface of the tubular portion.

100. A method of making a self-sealing vascular cuff graft, comprising:

attaching a beading disposed generally helically about a substantially tubular ePTFE substrate having a first end and a second end extending along a longitudinal axis;

coupling a flared vascular cuff to one of the first and second ends; and

bonding the coupled vascular cuff and generally tubular ePTFE substrate.

101. The method according to claim 100, wherein the coupling comprises rotating a proximal generally tubular portion of the cuff over the beading while applying a force in a proximal direction.

102. The method according to claim 100, wherein the bonding comprises applying an aprotic solvent.

103. The method according to claim 102, wherein the bonding comprises applying tetrahydrofuran (THF) to one or both of the cuff and substrate.

104. A method of making a self-sealing vascular graft, comprising:

providing an elastomeric sealant layer over a length of an outer surface of an ePTFE substrate; and

disposing a foam layer over at least a portion of the sealant layer, wherein a thickness of the foam layer is substantially greater than a thickness of a wall of the substrate.

105. The method according to claim 104, wherein the thickness of the foam layer is about two times the thickness of the wall of the substrate.

117. The method according to claim 104, wherein the disposing comprises spraying a polymeric solution over the sealant layer, wherein the polymeric solution comprises tetrahydrofuran (THF).

118. The method according to claim 117, wherein the polymeric solution comprises a polycarbonate polyurethane, and wherein the spraying of the solution comprises utilizing a spray gun with a nozzle and maintaining a distance between the graft and the nozzle during spraying in the range of about 12 inches to about 20 inches so that a foam layer of polyurethane is provided on the graft.

119. The method according to claim 118, wherein preparation of the polymeric solution comprises heating the polycarbonate polyurethane prior to mixing with THF.

120. The method according to claim 117, wherein preparation of the polymeric solution comprises adding about 88% by weight of polycarbonate polyurethane to THF.

121. The method according to claim 117, further comprising placing the graft in an oven set at a temperature in the range of about 50 degrees C. to about 70 degrees C. for a length of time in the range of about 1 hour to about 24 hours.

122. The method according to claim 104, further comprising helically wrapping a beading around the graft under tension to embed the beading in the foam layer.

123. The self-sealing vascular graft according to claim 122, wherein the beading comprises a radiopaque material selected from the group consisting essentially of barium sulfate, bismuth subcarbonate, bismuth trioxide, tungsten, or tantalum and combinations thereof.

124. The self-sealing vascular graft according to claim 122, wherein the beading comprises a material selected from the group consisting essentially of shape memory material, superelastic metals, stainless steel, polyester, nylon, polyurethane, PTFE, or ePTFE and combinations thereof.

125. The method according to claim 122, wherein the force of the tension is about 500 grams and wherein helically wrapping comprises moving the beading through a solution including THF prior to contacting the beading with the graft.

126. The method according to claim 104, further comprising disposing a second foam layer over the foam layer such that the combined thickness of the substrate wall, sealant layer, foam layer and second foam layer is in the range of about 1 mm to about 2 mm.

127. The method according to claim 126, further comprising helically wrapping a polymeric tape over the second foam layer such that edges of adjacent windings of the tape overlap.

128. The method according to claim 127, wherein the polymeric tape comprises ePTFE and wherein helically wrapping the tape comprises applying THF to the tape.

129. The method according to claim 127, wherein the polymeric tape comprises ePTFE and wherein helically wrapping the tape comprises applying tension to the tape.

106-116. -116. (canceled)

130-141. -141. (canceled)

142. A method of making a self-sealing vascular graft, comprising:

dispensing at least one layer of polyurethane material onto a surface of an ePTFE substrate; and

bonding an ePTFE member to the polyurethane material.

143. The method according to claim 142, wherein the bonding comprises soaking the ePTFE member in a solvent prior to contacting with the polyurethane material.

144. The method according to claim 142, wherein the bonding comprises spraying the ePTFE member with a solvent after positioning the ePTFE member over the polyurethane material.

145. The method according to claim 142, wherein the bonding comprises passing the ePTFE member through a solvent immediately prior to contacting with the polyurethane material.

146. The method according to claim 145, wherein the passing comprises moving the ePTFE member through a dispensing apparatus comprising a pressurized tube with one or more openings in a wall thereof and an article positioned over the one or more openings, the pressurized tube being connected to a reservoir containing the solvent, a pressure control device and a regulator, the ePTFE member passing over the article that is first saturated by the solvent such that a substantially even amount of solvent is applied to the ePTFE member.

147. The method according to claim 142, wherein the ePTFE member is fed from a spool on a pulley system and applied to the polyurethane material while the substrate is rotated.

148. The method according to claim 143, wherein the solvent comprises tetrahydrofuran (THF).

149. The method according to claim 142, wherein the ePTFE member is a length of ePTFE tape.

152. The method according to claim 142, wherein the at least one layer of polyurethane material comprises a first foam layer, the first foam layer being dispensed on a mid-portion of the substrate such that a length up to about 5.0 cm from each end of the substrate is free of the first foam layer.

153. The method according to claim 152, further comprising a second foam layer dispensed over the first foam layer.

154. The method according to claim 142, further comprising at least one beading positioned about the at least one layer of polyurethane material.

155. The method according to claim 154, wherein the at least one beading comprises a first beading and a second beading with respective cross-sectional areas, the cross-sectional area of the first beading being greater than the cross-sectional area of the second beading.

156. The method according to claim 155, wherein the first beading is positioned about a mid-portion of the substrate and the second beading is positioned about each end of the substrate.

157. The method according to claim 142, further comprising attaching a cuff to an end of the substrate.

159. The method according to claim 142, further comprising positioning an ePTFE sleeve over each end of the substrate.

150-151. -151. (canceled)

158. (canceled)

160-162. -162. (canceled)