Compliant blood vessel graft

Abstract

A graft for replacement of a section of an artery and methods of making the graft. The graft comprises a flexible, resilient, generally tubular external support and a blood vessel segment, e.g., a vein segment, carried within and having an ablumenal surface in contact with and supported by the tubular support, the graft being capable of resilient radial expansion in a manner mimicking the radial compliance properties of an artery.

1 . A flexible, resilient, generally tubular external support within which may be supported a vein segment to form a venous graft mimicking the compliance properties of a healthy artery, the tubular support being capable of resilient radial expansion in a manner providing compliance in the range of 3 to 30%/100 mm Hg.  
   
   
       2 . The tubular external support of  claim 1  in which said support comprises a knit wire mesh.  
   
   
       3 . The tubular external support of  claim 1  in which said support comprises a braided wire mesh including an element for controlling the degree of axial extension of the support.  
   
   
       4 . The tubular external support of  claim 3  in which said element comprises a thread attached to and carried internally of the support.  
   
   
       5 . The tubular external support of  claim 1  including a vein segment carried within the support, the vein segment having an ablumenal surface in contact with, and supported by, said tubular support.  
   
   
       6 . A venous graft for replacement of a section of an artery, the graft comprising a flexible, resilient, generally tubular external support and a vein segment carried within and having an ablumenal surface in contact with and supported by the tubular support, the venous graft being capable of resilient radial expansion in a manner mimicking the compliance properties of an artery.  
   
   
       7 . The venous graft of  claim 6  wherein said tubular support is capable of said resilient radial expansion without significant axial dimensional changes.  
   
   
       8 . The venous graft of  claim 6  wherein the compliance of the graft ranges from 3 to 30%/100 mm Hg.  
   
   
       9 . The venous graft of  claim 6  wherein the external support comprises a generally tubular fiber mesh capable of expanding in diameter through resilient movement of wires of the mesh to accommodate radial expansion of the vein segment supported in it sufficient to provide the graft with said compliance.  
   
   
       10 . The venous graft of  claim 6  wherein said external support comprises a knit, tubular mesh capable of expanding radially to accommodate radial expansion of the vein segment supported in it within said compliance range.  
   
   
       11 . The venous graft of  claim 6  wherein said external support comprises a braided fiber mesh so configured as to exhibit radial expansion in said compliance range without significant reduction in the axial length of the support.  
   
   
       12 . The venous graft of  claim 11  wherein said fiber mesh is made of metal wire.  
   
   
       13 . The venous graft of  claim 12  wherein said metal wire is of stainless steel or of a cobalt chrome alloy.  
   
   
       14 . The venous graft of  claim 11  wherein said metal wire is a shape memory alloy.  
   
   
       15 . The venous graft of  claim 11  wherein said fiber mesh is polymeric.  
   
   
       16 . The venous graft of  claim 6  wherein the ablumenal surface of the vein segment is bonded to said tubular support.  
   
   
       17 . The venous graft of  claim 6  wherein the vein segment and the tubular support are axially coextensive.  
   
   
       18 . The venous graft of  claim 10  wherein said knitted tubular fiber mesh is made from crimped fibers.  
   
   
       19 . The venous graft of  claim 9  wherein said tubular fiber mesh is made from fibers that are crimped after having been formed into said tubular mesh.  
   
   
       20 . A venous graft for replacement of a section of an artery, the graft comprising a flexible, resilient, knit wire mesh configured as a generally tubular external support and a vein segment carried within and having an ablumenal surface in contact with and supported by the tubular support, the support having resilient radial expansion and contraction characteristics that provide the venous graft with compliance properties mimicking those of an artery.  
   
   
       21 . The venous graft of  claim 1  wherein the compliance of the venous graft ranges from 3 to 30%/100 mm Hg.  
   
   
       22 . Method of producing a venous graft for use in replacing a section of an artery, comprising providing a segment of a vein and sheathing the segment in a generally tubular support in supportive contact with the ablumenal surface of the vein segment, the support being sufficiently flexible and radially resilient as to provide the graft with compliance properties mimicking the compliance properties of an artery.  
   
   
       23 . The method of  claim 22  including the step of cutting said venous graft from a longer section of vein sheathed in said tubular support, the ends of the vein and tubular support of the venous graft being coextensive.  
   
   
       24 . The method of  claim 22  including the step of supporting said generally tubular support upon an exterior surface of an applicator having an internal passage within which is positioned the vein segment, and removing the applicator to permit the tubular support to come into supportive contact with the ablumenal surface of the vein segment.  
   
   
       25 . The method of  claim 22  including the step of supporting said generally tubular support upon an exterior surface of an applicator having an internal passage, and, while passing the vein segment from within the applicator passage, drawing the tubular support onto the surface of the vein segment.  
   
   
       26 . The method of  claim 22  wherein said generally tubular support is chosen to be sufficiently radially resilient as to provide the venous graft with a compliance ranging from 3 to 30%/100 mm Hg.  
   
   
       27 . The method of  claim 24  wherein said tubular support is axially resilient, the method including the step of controlling axial dimension changes of the tubular support as the support comes into supportive contact with the vein segment to provide the venous graft with said compliance properties.  
   
   
       28 . The method of  claim 27  including the step of providing the tubular support with an axially extending, relatively inextensible element that restrains the tubular support from unwanted axial extension.  
   
   
       29 . The method of  claim 28  wherein said inextensible element comprises a flexible fiber positioned within the tubular support and between the tubular support and the ablumenal surface of the vein segment.  
   
   
       30 . The method of  claim 28  wherein the flexible fiber is a wire joined to the interior of the tubular support.  
   
   
       31 . The method of  claim 22  including the step of bonding the ablumenal surface of the vein segment to the tubular support.  
   
   
       32 . The tubular external support of  claim 1  in which said a knit wire mesh support comprises loops that alternate in size circumferentially of the support.  
   
   
       33 . The method of  claim 22  including forming said tubular support from a knit wire mesh, wherein said mesh is formed with loops that alternate in size circumferentially of the support.  
   
   
       34 . Method of producing a blood vessel graft comprising providing a segment of a blood vessel and sheathing the segment in a generally tubular support in supportive contact with the ablumenal surface of the vessel segment, the support being sufficiently flexible and radially resilient as to contribute to the compliance properties of the graft.  
   
   
       35 . The method of  claim 34  including supporting the generally tubular support on the exterior surface of an introducer tube, sliding the introducer tube over the vessel segment, and removing the introducer tube to enable the tubular support to contact the ablumenal surface of the vessel.  
   
   
       36 . The method of  claim 34  including affixing a cord to one end of the vessel segment, and maintaining tension on the vessel segment during sheathing of the vessel segment within the tubular support.  
   
   
       37 . The method of  claim 36  wherein the cord comprises a plug frictionally received within the introducer tube, the method including withdrawing the introducer tube from the vessel segment and tubular support, friction between the tube and plug maintaining the vessel in tension during such withdrawal.  
   
   
       38 . A blood vessel graft comprising a flexible, fiber mesh configured as a generally tubular external support and a blood vessel segment carried within and having an ablumenal surface in contact with and supported by the tubular support, the support having resilient radial expansion and contraction characteristics contributing to the compliance properties of the graft.  
   
   
       39 . The graft of  claim 38  including an adhesive adhering the tubular support to the ablumenal surface of the vessel to resist collapse of the vessel within the support.  
   
   
       40 . The graft of  claim 38  including an adhesive tape positioned around a portion of the tubular support, the tape including an adhesive that extends through the fiber mesh support and into adhesive contact with the ablumenal surface of the vessel.  
   
   
       41 . The graft of  claim 39  wherein said adhesive at least partially embeds said fiber mesh and adhesively contacts the ablumenal surface of the vessel.  
   
   
       42 . The graft of  claim 39  wherein said adhesive is formed as a coating on the fibers of the fiber mesh.  
   
   
       43 . Method of attachment of the graft of  claim 40  to another blood vessel, comprising cutting said portion of the graft bearing said adhesive tape to conform to the wall of the other blood vessel, the adhesive tape maintaining the cut end of the graft open and preventing fraying of the cut end.  
   
   
       44 . The method of  claim 43  wherein the graft is cut on the bias.  
   
   
       45 . Method of applying an adhesive tape to the exterior surface of a vessel graft that includes a vessel segment supported within a flexible, elastic fiber mesh tubular support, the method comprising compressing the graft between lengths of adhesive tape having an adhesive that penetrates the mesh to adhesively contact the ablumenal surface of the vessel, and allowing the graft to resume its tubular configuration.  
   
   
       46 . The method of  claim 45  including positioning the tape lengths in a deformable clip, inserting a segment of the stent in the clip between the tape lengths, deforming the clip to compress and flatten the stent, and removing the clip.  
   
   
       47 . The graft of  claim 37  wherein said vessel is of porcine or bovine origin.  
   
   
       48 . A graft for replacement of a section of an artery, the graft comprising a flexible, resilient, knit wire mesh configured as a generally tubular external support and a blood vessel segment carried within and having an ablumenal surface in contact with and supported by the tubular support, the support having resilient radial expansion and contraction characteristics that provide the graft with compliance properties mimicking those of an artery.