Grafts with expandable regions and methods of making and using same - Patents.com

Abstract

A suitable graft with an expandable region and a suitable method of making and using the same are provided. [Solution] A vascular graft suitable for implantation, the graft having an expandable outflow region (42) for restoring patency of the graft after implantation into a body lumen. The graft includes a conduit having a wall. The conduit includes at least one inflow opening at an inflow end of a body region and an outflow opening at an outflow end of an outflow region opposite the at least one inflow opening. The wall includes a support structure and a biocompatible layer. The support structure along the outflow region is under continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer against the support structure.

Description

[Technical field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to U.S. Provisional Patent Application No. 61 / 857,181, filed July 22, 2013, the contents of which are incorporated by reference in their entirety herein.

[0002] FIELD OF THEINVENTION The present invention and disclosure relates to various embodiments of vascular grafts suitable for implantation, including the manufacture and use of such grafts. In certain embodiments of the disclosure, one or more expandable first regions are provided to restore patency of the graft after implantation into a body lumen. [Background technology]

[0003] BACKGROUND OF THEINVENTION Vascular diseases are prevalent throughout the world. Bypass surgery, in which a conduit, either synthetic or autologous, is implanted into an existing vessel to bypass a diseased portion of the vessel or to restore blood flow around a blocked or damaged blood vessel, is one of the most common treatments for such diseases.

[0004] Vascular grafts are also used as access sites in dialysis patients. The graft connects or bridges between arteries and veins in the patient's body. A needle is inserted into the graft, allowing blood to be withdrawn, passed through a hemodialysis machine, and returned to the patient through a second needle inserted into the graft.

[0005] A significant number of bypass grafts fail within 5 to 7 years. The average life span of hemodialysis grafts is even shorter, often less than 2 years. The primary cause of graft failure is graft closure due to tissue ingrowth and eventual thrombosis formation. The smaller the graft diameter, the higher the graft failure rate. Lost patency resulting from graft closure or collapse is particularly problematic at the outflow site where the outflow end of the graft contacts the vessel.

[0006] However, this problem has not been adequately addressed by conventional techniques for restoring patency, which typically include surgical procedures (e.g., thrombectomy or percutaneous thrombectomy) or chemical intervention techniques (e.g., administration of anticoagulant or antiplatelet drugs such as ticlopidine, aspirin, dipyridimole, or clopidogrel) to remove ingrowth tissue or clots that may otherwise contribute to graft failure. In particular, surgery and chemical interventions may introduce unnecessary risks (e.g., infection, bleeding, etc.) and are often inadequate to be effective in maintaining patency over longer periods of time.

[0007] Thus, there is a need for grafts whose patency can be easily restored after implantation without requiring dangerous and ineffective chemical or surgical intervention. There is also a need for different graft constructions that take advantage of various features of the grafting technology disclosed herein. Summary of the Invention [Means for solving the problem]

[0008] (Summary) There is a need for a vascular graft that has an expandable outflow region that allows patency to be easily restored after implantation without requiring dangerous and ineffective chemical or surgical intervention. The present disclosure and embodiments of the invention are directed to further solutions to address the aforementioned needs, in addition to having other desirable properties.

[0009] According to an embodiment of the invention, a graft is provided. The graft includes a conduit having a wall. The conduit includes at least one inflow opening at an inflow end of a body region and an outflow opening at an outflow end of an outflow region opposite the at least one inflow opening. The wall includes a support structure and a biocompatible layer. The support structure along the outflow region is under continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer against the support structure.

[0010] According to an aspect of the invention, the compressive stress resulting from the continuous applied load in the outflow region exceeds the compressive stress resulting from the continuous applied load in the body region. According to an aspect of the invention, the compressive stress experienced by the support structure resulting from the continuous applied load in the outflow region is progressively greater in each section along the support structure that is progressively more distal from the at least one inlet opening. The compressive stress experienced by the support structure resulting from the continuous applied load in the outflow region causes elastic deformation of the support structure in the outflow region. According to an aspect of the invention, the elastic deformation of the support structure in the outflow region is progressively greater in each section along the support structure that is progressively more distal from the at least one inlet opening. The elastic deformation of the support structure in the outflow region is reversible. The compressive stress resulting from the continuous applied load in the body region does not elastically deform the support structure in the body region.

[0011] According to an aspect of the invention, the support structure has a plurality of effective outer diameter dimensions prior to combining with the biocompatible layer to form the wall, and the support structure has a substantially uniform effective outer diameter dimension after combining with the biocompatible layer to form the wall. The plurality of effective outer diameter dimensions along the body region can be effective outer diameter dimensions that are constant. The plurality of effective outer diameter dimensions along the outflow region can be effective outer diameter dimensions that are progressively larger at each section along the support structure that is progressively more distal from the at least one inflow opening. The substantially uniform effective outer diameter dimension can have a constant effective outer diameter dimension along the body region and a constrained effective outer diameter dimension along the outflow region. The constrained effective outer diameter dimension is approximately equal to the constant effective outer diameter dimension. Compressive stress resulting from a continuous applied load maintains the support structure along the outflow region at the constrained effective outer diameter dimension.

[0012] According to an aspect of the invention, a reaction force comprising a radial expansion force applied to the support structure along the outflow region causes plastic deformation of the biocompatible layer. A reaction force comprising a radial expansion force applied to the support structure in the outflow region causes a decrease in compressive stress experienced by the support structure. Following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to result in a plastically deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. Following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to result in a plastically deformed biocompatible layer. Following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to result in a support structure experiencing a residual compressive stress if there was previously a continuous compressive stress experienced by the support structure prior to application of the reaction force.

[0013] According to an aspect of the invention, a reaction force comprising a radial expansion force applied to the support structure in the outflow region reconfigures the support structure along the outflow region from a constrained effective outer diameter dimension to an expanded effective outer diameter dimension that exceeds the constrained effective outer diameter dimension along at least a portion of the support structure in the outflow region. According to an aspect of the invention, the expanded effective outer diameter dimension exceeds the constrained effective outer diameter dimension by at least 1 mm along at least a portion of the support structure in the outflow region. According to an aspect of the invention, the expanded effective outer diameter dimension of the support structure along the outflow region, after reconfiguration, exceeds the constrained effective outer diameter dimension by at least 1 mm along the entire portion of the support structure in the outflow region.

[0014] According to a further aspect of the invention, the conduit can include a second inlet opening. A longitudinal axis of the second inlet opening intersects a longitudinal axis of the at least one inlet opening at a non-parallel angle. According to an aspect of the invention, the non-parallel angle comprises an angle of about 25° to 45°. According to one aspect of the invention, the non-parallel angle is about 35°.

[0015] According to an aspect of the invention, the support structure is constructed from a shape memory alloy. According to one aspect of the invention, the support structure is constructed from Nitinol. The support structure can have a zigzag wire shape.

[0016] According to an aspect of the invention, the biocompatible layer comprises an expandable polymer. The biocompatible layer can include ePTFE. The biocompatible can include a biocompatible outer layer. The biocompatible layer can include a biocompatible inner layer. The biocompatible outer layer and the biocompatible inner layer encapsulate the support structure. According to one aspect of the invention, the biocompatible layer is not a surface-modifying coating.

[0017] According to one exemplary embodiment, a vascular graft is provided. The vascular graft includes a conduit having a wall. The wall includes at least one inflow opening at an inflow end of a body region and an outflow opening at an outflow end of an outflow region opposite the at least one inflow opening. The wall includes a support structure and a biocompatible layer. Prior to combining with the biocompatible layer to form the wall, the support structure includes a plurality of effective outer diameter dimensions along its length. The plurality of effective outer diameter dimensions includes a constant effective outer diameter dimension along the body region and an effective outer diameter dimension along the outflow region that is gradually larger at each section along the support structure that is gradually more distal from the at least one inflow opening. After combining with the biocompatible layer to form the wall, the support structure in the outflow region is under compressive stress resulting from a continuous applied load caused by the biocompatible layer that maintains the support structure along the outflow region at a constrained effective outer diameter dimension that is not gradually larger at each section along the support structure that is gradually more distal from the at least one inflow opening. After application of a reaction force to the support structure in the outflow region, the support structure in the outflow region reconfigures from a constrained effective outer diameter to an expanded effective outer diameter, at least a portion of which exceeds the constrained effective outer diameter by at least 1 millimeter.

[0018] According to an exemplary embodiment of the present invention, a method of expanding an outflow end of an implanted graft is provided. The method includes the steps of (a) identifying the implanted graft and (b) applying a reaction force. The vascular graft includes a conduit having a wall. The conduit includes at least one inflow opening at an inflow end of a body region and an outflow opening at an outflow end of an outflow region opposite the at least one inflow opening. The wall includes a support structure and a biocompatible layer. Prior to combining with the biocompatible layer to form the wall, the support structure includes a plurality of effective outer diameter dimensions including a constant effective outer diameter dimension along the body region and an effective outer diameter dimension along the outflow region that is progressively larger at each segment along the support structure that is progressively more distal from the at least one inflow opening. After combining with the biocompatible layer to form the wall, the support structure in the outflow region is under compressive stress resulting from a continuous applied load caused by the biocompatible layer that maintains the support structure in the outflow region at a constrained effective outer diameter dimension that is not progressively larger at each segment along the support structure that is progressively more distal from the at least one inflow opening. Application of a reaction force to the support structures in the outflow region reconfigures the support structures along the outflow region from a constrained effective outer diameter to an expanded effective outer diameter that exceeds the constrained effective outer diameter, thereby expanding the outflow region of the implanted graft.

[0019] According to an aspect of the invention, the outflow region comprises an outflow end that is collapsed, stenosed, or has persistent intimal thickening. An outflow end that is collapsed, stenosed, or has persistent intimal thickening compromises the patency of the vessel in which the graft is implanted.

[0020] According to an aspect of the invention, the step of applying a counterforce includes expanding an expandable device within the outflow region of the implanted graft. Prior to expansion of the expandable device, the expandable device is advanced to the outflow region. Prior to advancement of the expandable device to the outflow region, the expandable device is percutaneously introduced into the implanted graft.

[0021] According to an aspect of the invention, the expanded effective outer diameter exceeds the constrained effective outer diameter by at least 1 millimeter. According to an aspect of the invention, the expanded effective outer diameter exceeds the constrained effective outer diameter by at least 1 millimeter along any portion of the support structure within the outflow region.

[0022] According to one exemplary embodiment, a method of expanding an outflow region of an implanted graft is provided. The method includes the steps of (a) providing an implanted graft having an expandable outflow region, and (b) applying a reaction force to the outflow region. The implanted graft includes a conduit having a wall. The conduit includes at least one inflow opening at an inflow end of the body region and an outflow opening at an outflow end of the outflow region opposite the at least one inflow opening. The wall includes a support structure and a biocompatible layer. The support structure in the outflow region is under compressive stress resulting from an applied load caused by the biocompatible layer. Applying the reaction force to the support structure in the outflow region reconfigures the support structure along the outflow region from a constrained effective outer diameter dimension to an expanded effective outer diameter dimension that exceeds the constrained effective outer diameter dimension, thereby expanding the outflow end of the implanted graft.

[0023] According to one exemplary embodiment of the present invention, a method of making a graft with an expandable outflow end is provided. The method includes the steps of (a) providing a support structure having at least one inflow opening at an inflow end of a body region and an outflow opening at an outflow end of an outflow region opposite the at least one inflow opening. The support structure has a plurality of effective outer diameters comprising a constant effective outer diameter along the body region of the support structure and a gradually increasing effective outer diameter along the outflow region of the support structure. The method further includes the steps of (b) combining the support structure with at least one biocompatible layer to form a wall comprising the support structure and the at least one biocompatible layer. The method further includes the steps of (c) inserting a mandrel into the outflow opening proximal to the outflow end of the support structure. The method further includes (d) constraining the gradually increasing effective outer diameter proximal to the outflow region of the support structure with a compression wrap such that a continuous compressive stress results from a continuous applied load caused by the biocompatible layer to maintain the support structure at a constant effective outer diameter and a uniformly constrained effective outer diameter along the outflow region. The method further includes (e) sintering at least one biocompatible layer in a section within the outflow region. The present specification also provides, for example, the following items: (Item 1) A graft, a conduit having a wall, the conduit comprising: a first vascular insert region, a second vascular insert region, and a connecting region providing fluid communication therebetween, each of the first and second vascular insert regions comprising: a second fluid-flow region in fluid communication with the first fluid-flow region and an expandable third fluid-flow region opposite the first fluid-flow region, the second fluid-flow region joining together at a junction; a first opening disposed at an outermost end of the first fluid-flow region, a second opening disposed at an outermost end of the second fluid-flow region, and a third opening disposed at an outermost end of the third fluid-flow region, the first opening, the second opening, and a third opening disposed at an outermost end of the third fluid-flow region, the second openings of each of the first and second vascular insertion regions being interconnected via the connecting region in a manner allowing fluid communication therebetween; Equipped with wherein the wall comprises a support structure and a biocompatible layer; and A graft, wherein a support structure along at least a portion of the third fluid flow region of at least the first vascular insertion region is under continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer on the support structure. (Item 2) 2. The graft of claim 1, wherein a support structure along at least a portion of a third fluid flow region of the second vascular insertion region is under a continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer on the support structure. (Item 3) Item 1-2. The graft of item 1-2, wherein the compressive stress resulting from the continuous applied load in the third fluid-flow region exceeds the compressive stress resulting from the continuous applied load in either the first fluid-flow region or the second fluid-flow region. (Item 4) 3. The graft of claim 1, wherein the compressive stress experienced by the support structure resulting from successive applied loads in the third fluid flow region gradually decreases at each segment along the support structure until it is substantially constant approaching the junction. (Item 5) 3. The graft of claim 1, wherein the compressive stress experienced by the support structure resulting from the continuous applied load in the third fluid-flow region causes an elastic deformation of the support structure that is substantially constant within the third fluid-flow region and then progressively greater at each segment along the support structure that is progressively more distal from the first opening. (Item 6) 6. The graft of item 5, wherein the elastic deformation of the support structure within the third fluid-flow region is reversible such that reversing the elastic deformation of the support structure within the third fluid-flow region causes a diameter of the support structure within the third fluid-flow region to expand to a diameter less than an uncompressed diameter of the support structure that is not under compressive stress resulting from the continued applied load in the third fluid-flow region. (Item 7) Item 3. The graft of item 1-2, wherein the elastic deformation of the support structure within the first fluid-flow region due to compressive stress resulting from a continuous applied load within the first fluid-flow region is at most negligible. (Item 8) The graft of item 1-2, wherein the elastic deformation of the support structure in the second fluid-flow region due to compressive stress resulting from a continuous applied load in the second fluid-flow region is at most negligible. (Item 9) 3. The graft of claim 1, wherein prior to combining with the biocompatible layer and forming the wall, the support structure along the first fluid-flow region has a constant effective inner diameter dimension, and the support structure along the third fluid-flow region comprises an effective inner diameter dimension that is substantially constant before becoming progressively larger at each section along the support structure progressively more distal from the first opening. (Item 10) 10. The graft of claim 9, wherein after combination with the biocompatible layer to form the wall, the support structure has a substantially uniform effective inner diameter dimension comprising a constant effective inner diameter dimension along the first fluid-flow region and a constrained effective inner diameter dimension along the third fluid-flow region. (Item 11) Item 11. The graft of item 10, wherein the constrained effective inner diameter is approximately equal to the constant effective inner diameter. (Item 12) Item 12. The graft of item 11, wherein compressive stress resulting from the continuous applied load maintains the support structure along the third fluid flow region at the constrained effective inner diameter dimension. (Item 13) 13. The graft of claim 12, wherein a reaction force comprising a radial expansion force applied to the support structure along the third fluid flow region causes a permanent deformation of the biocompatible layer. (Item 14) 14. The graft of item 13, wherein a reaction force comprising a radial expansion force applied to the support structure in the third fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 15) Item 15. The graft of item 14, wherein following application of a reaction force comprising a radial expansion force applied to a support structure within the third fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 16) 16. The graft of claim 15, wherein following application of a reaction force comprising a radial expansion force applied to a support structure within the third fluid flow region, the graft reconfigures to result in the support structure experiencing a reduced compressive stress from the previously greater compressive stress experienced by the support structure prior to application of the reaction force. (Item 17) 17. The graft of claim 16, wherein a reaction force comprising a radial expansion force applied to the support structure in the third fluid-flow region reconfigures the support structure along the third fluid-flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that is greater than the constrained effective inner diameter dimension along at least a portion of the support structure in the third fluid-flow region. (Item 18) Item 18. The graft of item 17, wherein the expanded effective inner diameter dimension exceeds the constrained effective inner diameter dimension by at least 1 mm along at least a portion of the support structure within the third fluid flow region. (Item 19) 20. The graft of claim 18, wherein an effective inner diameter dimension of the support structure along the third fluid flow region is greater than the constrained effective inner diameter dimension along an adjacent portion of the support structure within the third fluid flow region. (Item 20) 3. The graft of claim 1, wherein the expandable third fluid flow region within at least the first vascular insertion region comprises an elongated expandable third fluid flow region. (Item 21) 21. The graft of item 1 or 20, wherein the expandable third fluid flow region within the second vascular insertion region comprises an elongated expandable third fluid flow region. (Item 22) 22. The graft of claim 20-21, wherein the elongated expandable third fluid flow region has a length that is greater than about 5 times the length of either the first fluid flow region or the second fluid flow region. (Item 23) 22. The graft of claim 20, wherein the length of the conduit between the junction and the outermost end of the third fluid flow region exceeds the combined length of the first fluid flow region and the second fluid flow region. (Item 24) 22. The graft of claim 20, wherein the length of the conduit between the junction and the outermost end of the third fluid flow region is at least about 50 millimeters. (Item 25) 22. The graft of claim 20-21, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable third fluid flow region gradually decreases in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the third fluid flow region. (Item 26) 22. The graft of claim 20, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable third fluid-flow region causes elastic deformation of the support structure within the elongated, expandable third fluid-flow region to gradually increase in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the third fluid-flow region. (Item 65) 60. The graft of claim 58 or 59, wherein the elastic deformation of the support structure within the elongated, expandable third fluid-flow region is reversible such that reversing the elastic deformation of the support structure within the elongated, expandable third fluid-flow region causes a diameter of the support structure within the elongated, expandable third fluid-flow region to expand to a diameter less than an uncompressed diameter of the support structure that is not under compressive stress resulting from the continuously applied load within the elongated, expandable third fluid-flow region. (Item 27) 22. The graft of claim 20, wherein elastic deformation of the support structure in the first and second fluid-flow regions due to compressive stress resulting from continuous applied loads in the first and second fluid-flow regions is at most negligible. (Item 28) 22. The graft of claim 20-21, wherein prior to combining with the biocompatible layer and forming the wall, the support structure in the first vascular insertion region has a constant effective inner diameter dimension along the first fluid-flow region and an effective inner diameter dimension along the third fluid-flow region that gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 29) 22. The graft of claim 20-21, wherein prior to combining with the biocompatible layer and forming the wall, the support structure in the second vascular insertion region has a constant effective inner diameter dimension along the first fluid-flow region and an effective inner diameter dimension along the third fluid-flow region that gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 30) 22. The graft of claim 20, wherein after combination with the biocompatible layer to form the wall, the support structure in the first vascular insertion region has a substantially uniform effective inner diameter dimension comprising a constant effective inner diameter dimension along the first fluid-flow region and a constrained effective inner diameter dimension along the elongated expandable third fluid-flow region. (Item 31) 22. The graft of claim 20, wherein after combination with the biocompatible layer to form the wall, the support structure in the second vascular insertion region has a substantially uniform effective inner diameter dimension comprising a constant effective inner diameter dimension along the first fluid-flow region and a constrained effective inner diameter dimension along the elongated expandable third fluid-flow region. (Item 32) 32. The graft of claim 30, wherein the constrained effective inner diameter is approximately equal to the constant effective inner diameter. (Item 33) 33. The graph of claim 32, wherein compressive stress resulting from the continuous applied load maintains the support structure along the elongated, expandable third fluid-flow region at the constrained effective inner diameter dimension. Suddenly. (Item 34) 34. The graft of claim 33, wherein a reaction force comprising a radial expansion force applied to the support structure along the elongated expandable third fluid flow region causes permanent deformation of the biocompatible layer. (Item 35) 35. The graft of claim 34, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 36) 36. The graft of claim 35, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 37) 37. The graft of claim 36, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress relative to the previously greater compressive stress experienced by the support structure prior to application of the reaction force. (Item 38) 38. The graft of claim 37, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated, expandable, third fluid-flow region reconfigures the support structure along the elongated, expandable, third fluid-flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that is greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated, expandable, third fluid-flow region. (Item 39) Item 39. The graft of item 38, wherein the expanded effective inner diameter dimension is at least 1 mm greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated expandable third fluid flow region. (Item 40) 40. The graft of claim 39, wherein after reconfiguration, an expanded effective inner diameter dimension of the support structure along the elongated, expandable third fluid flow region exceeds the constrained effective inner diameter dimension by at least 1 mm along a majority of the support structure within the elongated, expandable third fluid flow region. (Item 41) Item 1. The graft of item 1, wherein the longitudinal axis of the second fluid flow region intersects the longitudinal axis of the first fluid flow region at a non-parallel angle. (Item 42) Item 42. The graft of item 41, wherein the non-parallel angle comprises an angle of about 25° to 45°. (Item 43) Item 42. The graft of item 41, wherein the non-parallel angle comprises an angle of about 35°. (Item 44) 2. The graft of claim 1, wherein the second fluid flow region merges together at a junction with the first fluid flow region such that the first fluid flow region and the second fluid flow region are not perpendicular to each other. (Item 45) 2. The graft of claim 1, wherein the support structure is constructed from a shape memory alloy. (Item 46) 2. The graft of claim 1, wherein the support structure is constructed from Nitinol. (Item 47) Item 1 graft according to item 1, wherein the biocompatible layer comprises an expandable polymer. (Item 48) 2. The graft of claim 1, wherein the biocompatible layer comprises ePTFE. (Item 49) 2. The graft of claim 1, wherein the biocompatible layer further comprises a biocompatible outer layer. (Item 50) 50. The graft of claim 49, wherein the biocompatible layer further comprises a biocompatible inner layer. (Item 51) 51. The graft of claim 50, wherein the biocompatible outer layer and the biocompatible inner layer encapsulate the support structure. (Item 52) 2. The graft of claim 1, wherein the biocompatible layer is not a surface modifying coating. (Item 53) A graft, a conduit having a wall, the conduit comprising: a first inflow region having a first inflow end and a second inflow region having a second inflow end, the first and second inflow regions meeting together at an inflow junction in fluid communication with an elongated expandable outflow region opposite the first inflow region, the outflow region having an outflow end; a first inlet opening disposed at a first inlet end of the first inlet region, a second inlet opening disposed at a second inlet end of the second inlet region, and an outlet opening disposed at an outlet end of the outlet region; Equipped with wherein the wall comprises a support structure and a biocompatible layer; the support structure along at least a portion of the elongated expandable outflow region is under compressive stress resulting from an applied load caused by the biocompatible layer on the support structure; and A graft, wherein the length of the elongated expandable outflow region is more than twice the length of either the first inflow region or the second inflow region. (Item 54) 54. The graft of claim 53, wherein the elongated expandable outflow region has a length that exceeds a length of either the first inflow region or the second inflow region. (Item 55) Item 54. The graft of item 53, wherein the length of the conduit between the inflow junction and the outflow end is at least about 100 millimeters. (Item 56) 54. The graft of claim 53, wherein the compressive stress resulting from the continuous applied load in the elongated expandable outflow region exceeds the compressive stress resulting from the continuous applied load in either the first inflow region or the second inflow region. (Item 57) 54. The graft of item 53, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongate expandable outflow region gradually increases in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the one or more initial sections. (Item 58) Item 54. The graft of item 53, wherein compressive stress experienced by the support structure resulting from continuous applied load within the elongated expandable outflow region causes elastic deformation of the support structure within the elongated expandable outflow region. (Item 59) Item 59. The graft of item 58, wherein the elastic deformation of the support structure within the outflow region increases in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the one or more initial sections. (Item 60) Item 59. The graft of item 58, wherein the elastic deformation of the support structure within the elongated expandable outflow region is reversible. (Item 61) Item 54. The graft of item 53, wherein reversing the elastic deformation of the support structure within the elongated expandable outflow region causes a diameter of the support structure within the elongated expandable outflow region to expand to a diameter greater than an uncompressed diameter of the support structure that is not under compressive stress resulting from a continued applied load within the elongated expandable outflow region. (Item 62) Item 54. The graft of item 53, wherein elastic deformation of the support structure in the second inflow region due to compressive stress resulting from continuous applied load in the second inflow region is at most negligible. (Item 63) Item 54. The graft of item 53, wherein elastic deformation of the support structure in the first inflow region due to compressive stress resulting from continuous applied load in the first inflow region is at most negligible. (Item 64) 54. The graft of claim 53, wherein the support structure has a plurality of effective inner diameter dimensions prior to combining with the biocompatible layer to form the wall, and the support structure has a substantially uniform effective inner diameter dimension after combining with the biocompatible layer to form the wall. (Item 65) Item 65. The graft of item 64, wherein the effective inner diameter dimension along the first inflow region comprises a constant effective inner diameter dimension. (Item 66) Item 65. The graft of item 64, wherein the effective inner diameter dimension along the elongate expandable outflow region prior to combination with the biocompatible layer increases along one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 67) Item 65. The graft of item 64, wherein the substantially uniform effective inner diameter dimension after combination with the biocompatible layer comprises a constant effective inner diameter dimension along the first inflow region and a constrained effective inner diameter dimension along the elongated expandable outflow region. (Item 68) Item 68. The graft of item 67, wherein the constrained effective inner diameter is approximately equal to the constant effective inner diameter. (Item 69) Item 68. The graft of item 67, wherein compressive stress resulting from the continuous applied load maintains the support structure along the elongated expandable outflow region at the constrained effective inner diameter dimension. (Item 70) Item 68. The graft of item 67, wherein a reaction force comprising a radial expansion force applied to the support structure along the elongated expandable outflow region causes permanent deformation of the biocompatible layer. (Item 71) 70. The graft of claim 67, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable outflow region causes a decrease in compressive stress experienced by the support structure. (Item 72) Item 68. The graft of item 67, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable outflow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 73) Item 68. The graft of item 67, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable outflow region, the graft reconfigures to provide a permanently deformed biocompatible layer. (Item 74) Item 68. The graft of item 67, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable outflow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress from the compressive stress previously experienced by the support structure prior to application of the reaction force. (Item 75) Item 68. The graft of item 67, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongate expandable outflow region reconfigures the support structure along the elongate expandable outflow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that is greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongate expandable outflow region. (Item 76) Item 76. The graft of item 75, wherein the expanded effective inner diameter dimension exceeds the constrained effective inner diameter dimension by at least 1 mm along at least a portion of the support structure within the elongated expandable outflow region. (Item 77) Item 76. The graft of item 75, wherein the expanded effective inner diameter dimension of the support structure along the elongated expandable outflow region, after reconfiguration, exceeds the constrained effective inner diameter dimension by at least 1 mm along a majority of the support structure within the elongated expandable outflow region. (Item 78) Item 54. The graft of item 53, wherein the longitudinal axis of the second inflow region intersects the longitudinal axis of the first inflow region at a non-parallel angle. (Item 79) Item 79. The graft of item 78, wherein the non-parallel angle comprises an angle of about 25° to 45°. (Item 80) Item 79. The graft of item 78, wherein the non-parallel angle comprises an angle of about 35°. (Item 81) Item 79. The graft of item 78, wherein the second inflow region merges together at the inflow junction with the first inflow region such that the first inflow region and the second inflow region are not perpendicular to one another. (Item 82) 54. The graft of claim 53, wherein the support structure is constructed from a shape memory alloy. (Item 83) Item 54. The graft of item 53, wherein the support structure is constructed from Nitinol. (Item 84) 54. The graft of claim 53, wherein the biocompatible layer comprises an expandable polymer. (Item 85) 54. The graft of claim 53, wherein the biocompatible layer comprises ePTFE. (Item 86) 54. The graft of claim 53, wherein the biocompatible layer further comprises a biocompatible outer layer. (Item 87) Item 87. The graft of item 86, wherein the biocompatible layer further comprises a biocompatible inner layer. (Item 88) Item 88. The graft of item 87, wherein the biocompatible outer layer and the biocompatible inner layer encapsulate the support structure. (Item 89) 89. The graft of claim 88, wherein the biocompatible layer is not a surface modifying coating. (Item 90) Item 89. The graft of item 88, wherein the support structure is constructed from a shape memory alloy. (Item 91) Item 89. The graft of item 88, wherein the support structure is constructed from Nitinol. (Item 92) A graft, a conduit having a wall, the conduit comprising: a first vascular insert region, a second vascular insert region, and a connecting region providing fluid communication therebetween; The first vascular insertion region comprises: a first fluid-flow region and a second fluid-flow region meeting together at a junction in fluid communication with a third fluid-flow region opposite the first fluid-flow region; a first opening disposed at an outermost end of the first fluid-flow region, a second opening disposed at an outermost end of the second fluid-flow region, and a third opening disposed at an outermost end of the third fluid-flow region; Equipped with The second vascular insertion region comprises: a fourth fluid-flow region extending from a fourth opening disposed adjacent the connecting region to an opposing fifth opening disposed adjacent a terminal portion of the second vascular insertion region, the second opening of the first vascular insertion region being connected to the fourth opening of the second vascular insertion region via the connecting region in a manner allowing fluid communication therebetween; Equipped with wherein the wall comprises a support structure and a biocompatible layer; and A graft, wherein the support structure along at least a portion of the third fluid flow region is under a continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer on the support structure. (Item 93) Item 93. The graft of item 92, wherein the compressive stress resulting from the continuous applied load in the third fluid-flow region exceeds the compressive stress resulting from the continuous applied load in either the first fluid-flow region or the second fluid-flow region. (Item 94) Item 93. The graft of item 92, wherein the compressive stress experienced by the support structure resulting from the continued applied load in the third fluid flow region is progressively greater at each section along the support structure progressively more distal from the first opening, the stress becoming substantially constant proximal to the junction. (Item 95) Item 93. The graft of item 92, wherein compressive stresses experienced by the support structure resulting from successive applied loads in the third fluid-flow region cause elastic deformation of the support structure within the third fluid-flow region that is progressively greater toward the third fluid-flow region at each section along the support structure that is progressively more distal from the junction. (Item 96) Item 96. The graft of item 95, wherein the elastic deformation of the support structure within the third fluid-flow region is reversible such that reversing the elastic deformation of the support structure within the third fluid-flow region causes a diameter of the support structure within the third fluid-flow region to expand to a diameter less than the uncompressed diameter of the support structure that is not under compressive stress resulting from the continued applied load in the third fluid-flow region. (Item 97) Item 93. The graft of item 92, wherein elastic deformation of the support structure within the first fluid-flow region due to compressive stress resulting from a continuous applied load within the first fluid-flow region is at most negligible. (Item 98) Item 93. The graft of item 92, wherein the elastic deformation of the support structure along a central portion of the second fluid-flow region due to compressive stress resulting from an applied load within the second fluid-flow region is at most negligible. (Item 99) Item 93. The graft of item 92, wherein prior to combining with the biocompatible layer and forming the wall, the support structure along the first fluid-flow region has a constant effective inner diameter dimension and the support structure along the third fluid-flow region has an effective inner diameter dimension that is progressively larger toward the third opening at each section along the support structure that is progressively more distal from the junction. (Item 100) 100. The graft of claim 99, wherein after combination with the biocompatible layer to form the wall, the support structure has a substantially uniform effective inner diameter dimension comprising a constant effective inner diameter dimension along the first fluid-flow region and a constrained effective inner diameter dimension along the third fluid-flow region. (Item 101) Item 101. The graft of item 100, wherein the constrained effective inner diameter is approximately equal to the constant effective inner diameter. (Item 102) Item 102. The graft of item 101, wherein compressive stress resulting from the continuous applied load maintains the support structure along the third fluid flow region at the constrained effective inner diameter dimension. (Item 103) Item 103. The graft of item 102, wherein a reaction force comprising a radial expansion force applied to the support structure along the third fluid flow region causes permanent deformation of the biocompatible layer. (Item 104) Item 104. The graft of item 103, wherein a reaction force comprising a radial expansion force applied to the support structure in the third fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 105) The graft of item 104, wherein following application of a reaction force comprising a radial expansion force applied to a support structure within the third fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 106) The graft of item 105, wherein following application of a reaction force comprising a radial expansion force applied to a support structure within the third fluid flow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress compared to the previously greater compressive stress experienced by the support structure prior to application of the reaction force. (Item 107) Item 107. The graft of item 106, wherein a reaction force comprising a radial expansion force applied to a support structure in the third fluid-flow region reconfigures the support structure along the third fluid-flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that is greater than the constrained effective inner diameter dimension along at least a portion of the support structure in the third fluid-flow region. (Item 108) Item 108. The graft of item 107, wherein the expanded effective inner diameter dimension exceeds the constrained effective inner diameter dimension by at least 1 mm along at least a portion of the support structure within the third fluid flow region. (Item 109) Item 109. The graft of item 108, wherein the expanded effective inner diameter dimension of the support structure along the third fluid flow region, after reconfiguration, exceeds the constrained effective inner diameter dimension by at least 1 mm along the entirety of the expandable portion of the radial support device structure within the third fluid flow region. (Item 110) Item 93. The graft of item 92, wherein the expandable third fluid flow region comprises an elongated expandable third fluid flow region. (Item 111) Item 111. The graft of item 110, wherein the elongated expandable third fluid flow region has a length that is greater than about 5 times the length of either the first fluid flow region or the second fluid flow region. (Item 112) Item 11. The graft of item 110, wherein the length of the conduit between the junction and the outermost end of the third fluid flow region exceeds the combined length of the first fluid flow region and the second fluid flow region. (Item 113) Item 111. The graft of item 110, wherein the length of the conduit between the junction and the outermost end of the third fluid flow region is at least about 50 millimeters. (Item 114) Item 111. The graft of item 110, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable third fluid flow region gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 115) Item 111. The graft of item 110, wherein compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable third fluid-flow region causes elastic deformation of the support structure within the elongated, expandable third fluid-flow region to gradually decrease in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 116) Item 117. The graft of item 115, wherein the elastic deformation of the support structure within the elongated, expandable, third fluid-flow region is reversible such that reversing the elastic deformation of the support structure within the elongated, expandable, third fluid-flow region expands a diameter of the support structure within the elongated, expandable, third fluid-flow region to a diameter less than an uncompressed diameter of the support structure that is not under compressive stress resulting from the continued applied load within the elongated, expandable, third fluid-flow region. Item 117. The graft of item 116, wherein elastic deformation of the support structure in the first and second fluid-flow regions due to compressive stress resulting from continuous applied loads in the first and second fluid-flow regions is at most negligible. (Item 118) Item 119. The graft of item 117, wherein prior to combining with the biocompatible layer and forming the wall, the support structure in the first vascular insertion region has a constant effective inner diameter dimension along the first fluid flow region and an effective inner diameter dimension along the third fluid flow region that gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. Item 19. The graft of item 118, wherein after combination with the biocompatible layer to form the wall, the support structure in the first vascular insertion region has a substantially uniform effective inner diameter dimension comprising a constant effective inner diameter dimension along the first fluid-flow region and a constrained effective inner diameter dimension along the elongated expandable third fluid-flow region. (Item 120) Item 120. The graft of item 119, wherein the constrained effective inner diameter is approximately equal to the constant effective inner diameter. (Item 121) Item 121. The graft of item 120, wherein compressive stress resulting from the continuous applied load maintains the support structure along the elongated expandable third fluid flow region at the constrained effective inner diameter dimension. (Item 122) Item 122. The graft of item 121, wherein a reaction force comprising a radial expansion force applied to the support structure along the elongated expandable third fluid flow region causes permanent deformation of the biocompatible layer. (Item 123) Item 123. The graft of item 122, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 124) Item 124. The graft of item 123, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 125) The graft of item 124, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable third fluid flow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress from the greater compressive stress previously experienced by the support structure prior to application of the reaction force. (Item 126) Item 126. The graft of item 125, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated, expandable third fluid-flow region reconfigures the support structure along the elongated, expandable third fluid-flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that exceeds the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated, expandable third fluid-flow region. (Item 127) Item 127. The graft of item 126, wherein the expanded effective inner diameter dimension is at least 1 mm greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated expandable third fluid flow region. (Item 128) Item 128. The graft of item 127, wherein the expanded effective inner diameter dimension of the support structure along the elongated, expandable third fluid flow region is at least 1 mm greater than the constrained effective inner diameter dimension along a majority of the support structure within the elongated, expandable third fluid flow region after reconfiguration. (Item 129) The graft of item 92 or 110, wherein a portion of the fourth fluid flow region is expandable. (Item 130) Item 130. The graft of item 129, wherein the expandable portion of the support structure along the fourth fluid flow region is under continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer on the support structure. (Item 131) Item 131. The graft of item 130, wherein compressive stress experienced by a portion of the support structure resulting from a continuous applied load within the expandable fourth fluid flow region causes elastic deformation of the support structure within the expandable radial support device portion of the fourth fluid flow region. (Item 132) Item 132. The graft of item 131, wherein the elastic deformation of the support structure within the expandable fourth fluid flow region is reversible such that reversing the elastic deformation causes the diameter of the support structure to expand to a diameter less than the uncompressed diameter of the support structure that is not under compressive stress resulting from continued applied load within the expandable fourth fluid flow region. (Item 133) Item 133. The graft of item 132, wherein compressive stress resulting from the continuous applied load maintains the support structure along the expandable fourth fluid flow region at a constrained effective inner diameter dimension. (Item 134) Item 134. The graft of item 133, wherein a reaction force comprising a radial expansion force applied to the support structure along the expandable fourth fluid flow region causes permanent deformation of the biocompatible layer. (Item 135) Item 135. The graft of item 134, wherein a reaction force comprising a radial expansion force applied to the support structure within the expandable fourth fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 136) Item 136. The graft of item 135, wherein following application of a reaction force comprising a radial expansion force applied to the support structure in the expandable fourth fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure in the expandable fourth fluid flow region that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 137) Item 137. The graft of item 136, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the expandable fourth fluid flow region, the graft reconfigures to provide a permanently deformed biocompatible layer. (Item 138) The graft of item 137, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the expandable fourth fluid flow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress from the previously greater compressive stress experienced by the support structure prior to application of the reaction force. (Item 139) Item 139. The graft of item 138, wherein a reaction force comprising a radial expansion force applied to the support structure in the expandable fourth fluid flow region reconfigures the support structure along the expandable fourth fluid flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that exceeds the constrained effective inner diameter dimension along at least a portion of the support structure in the expandable fourth fluid flow region. (Item 140) Item 140. The graft of item 139, wherein the expanded effective inner diameter dimension exceeds the constrained effective inner diameter dimension by at least 1 mm along at least a portion of the expandable support structure within the fourth fluid flow region. (Item 141) Item 141. The graft of item 140, wherein the expanded effective inner diameter dimension of the support structure along the fourth fluid flow region, after reconfiguration, exceeds the constrained effective inner diameter dimension along the expandable support structure within the entire fourth fluid flow region by at least 1 mm. (Item 142) Item 111. The graft of item 92 or 110, wherein the fourth fluid flow region comprises an elongated, expandable fourth fluid flow region. (Item 143) Item 143. The graft of item 142, wherein the elongated expandable fourth fluid flow region has a length greater than about 70 millimeters. (Item 144) Item 144. The graft of item 143, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable fourth fluid-flow region gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the fifth fluid-flow region. (Item 145) Item 145. The graft of item 144, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated, expandable, fourth fluid-flow region causes elastic deformation of the support structure within the elongated, expandable, fourth fluid-flow region to gradually decrease in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the fifth fluid-flow region. (Item 146) Item 146. The graft of item 145, wherein the elastic deformation of the support structure within the elongated, expandable, fourth fluid-flow region is reversible such that reversing the elastic deformation causes the diameter of the support structure within the elongated, expandable, fourth fluid-flow region to expand to a diameter less than the uncompressed diameter of the support structure that is not under compressive stress resulting from a continuously applied load within the elongated, expandable, fourth fluid-flow region. (Item 147) Item 147. The graft of item 146, wherein, prior to combining with the biocompatible layer and forming the wall, the support structure within the elongated expandable fourth fluid flow region has an effective inner diameter dimension that gradually decreases in one or more initial sections along the support structure before becoming constant across each section progressively more distal from the one or more initial sections. (Item 148) Item 148. The graft of item 147, wherein after combination with the biocompatible layer to form the wall, the support structure within the elongated expandable fourth fluid flow region has a constrained effective inner diameter dimension. (Item 149) Item 149. The graft of item 148, wherein compressive stress resulting from the continuous applied load maintains the support structure along the elongated expandable fourth fluid flow region at the constrained effective inner diameter dimension. (Item 150) Item 150. The graft of item 149, wherein a reaction force comprising a radial expansion force applied to the support structure along the elongated expandable fourth fluid flow region causes permanent deformation of the biocompatible layer. (Item 151) Item 151. The graft of item 150, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable fourth fluid flow region causes a decrease in compressive stress experienced by the support structure. (Item 152) Item 152. The graft of item 151, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable fourth fluid flow region, the graft reconfigures to result in a permanently deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 153) The graft of item 152, wherein following application of a reaction force comprising a radial expansion force applied to the support structure within the elongated expandable fourth fluid flow region, the graft reconfigures to result in a support structure experiencing a reduced compressive stress relative to the previously greater compressive stress experienced by the support structure prior to application of the reaction force. (Item 154) Item 154. The graft of item 153, wherein a reaction force comprising a radial expansion force applied to the support structure within the elongated, expandable, fourth fluid-flow region reconfigures the support structure along the elongated, expandable, fourth fluid-flow region from the constrained effective inner diameter dimension to an expanded effective inner diameter dimension that is greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated, expandable, fourth fluid-flow region. (Item 155) Item 155. The graft of item 154, wherein the expanded effective inner diameter dimension is at least 1 mm greater than the constrained effective inner diameter dimension along at least a portion of the support structure within the elongated expandable fourth fluid flow region. (Item 156) Item 156. The graft of item 155, wherein the expanded effective inner diameter dimension of the support structure along the elongated, expandable, fourth fluid flow region, after reconfiguration, exceeds the constrained effective inner diameter dimension by at least 1 mm along a majority of the support structure within the elongated, expandable, fourth fluid flow region. (Item 157) Item 93. The graft of item 92, wherein the longitudinal axis of the second fluid flow region intersects the longitudinal axis of the first fluid flow region at a non-parallel angle. (Item 158) Item 158. The graft of item 157, wherein the non-parallel angle comprises an angle of about 25° to 45°. (Item 159) Item 158. The graft of item 157, wherein the non-parallel angle comprises an angle of about 35°. (Item 160) Item 93. The graft of item 92, wherein the second fluid flow region merges together at a junction with the first fluid flow region such that the first fluid flow region and the second fluid flow region are not perpendicular to each other. (Item 161) Item 93. The graft of item 92, wherein the support structure is constructed from a shape memory alloy. (Item 162) Item 93. The graft of item 92, wherein the support structure is constructed from Nitinol. (Item 163) Item 93. The graft of item 92, wherein the biocompatible layer comprises an expandable polymer. (Item 164) 93. The graft of claim 92, wherein the biocompatible layer comprises ePTFE. (Item 165) Item 93. The graft of item 92, wherein the biocompatible layer further comprises a biocompatible outer layer. (Item 166) Item 166. The graft of item 165, wherein the biocompatible layer further comprises a biocompatible inner layer. (Item 167) Item 167. The graft of item 166, wherein the biocompatible outer layer and the biocompatible inner layer encapsulate the support structure. (Item 168) 93. The graft of claim 92, wherein the biocompatible layer is not a surface modifying coating. (Item 169) A graft, a conduit having a wall, the conduit comprising: at least one inlet opening at an inlet end of the body region; an outlet opening at an outlet end of the outlet region opposite the at least one inlet opening; Equipped with wherein the wall comprises a support structure and a biocompatible layer; and A graft, wherein the support structure along the outflow region is under continuous compressive stress resulting from a continuous applied load caused by the biocompatible layer on the support structure. (Item 170) Item 170. The graft of item 169, wherein the compressive stress resulting from the continuous applied load in the outflow region exceeds the compressive stress resulting from the continuous applied load in the body region. (Item 171) 171. A graft as described in either of items 169 or 170, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the outflow region is progressively greater in each section along the support structure that is progressively more distal from the at least one inflow opening. (Item 172) A graft as described in any of items 169-171, wherein compressive stress experienced by the support structure resulting from continuous applied load in the outflow region causes elastic deformation of the support structure in the outflow region. (Item 173) 173. A graft as described in any of items 169-172, wherein the elastic deformation of the support structure in the outflow region is progressively greater in each section along the support structure that is progressively more distal from the at least one inflow opening. (Item 174) A graft described in any of items 169-173, wherein the elastic deformation of the support structure in the outflow region is reversible. (Item 175) 175. The graft of any of paragraphs 169-174, wherein compressive stresses resulting from continuous applied load within the body region do not elastically deform support structures within the body region. (Item 176) 176. The graft of any of items 169-175, wherein the support structure has a plurality of effective outer diameter dimensions prior to combination with the biocompatible layer to form the wall, and the support structure has a substantially uniform effective outer diameter dimension after combination with the biocompatible layer to form the wall. (Item 177) Item 177. The graft of item 176, wherein the plurality of effective outer diameter dimensions along the body region comprises a constant effective outer diameter dimension. (Item 178) Item 178. The graft of item 177, wherein a plurality of effective outer diameter dimensions along the outflow region comprise progressively larger effective outer diameter dimensions at each section along the support structure that is progressively more distal from the at least one inflow opening. (Item 179) Item 179. The graft of item 178, wherein the substantially uniform effective outer diameter comprises a constant effective outer diameter along the body region and a constrained effective outer diameter along the outflow region. (Item 180) Item 180. The graft of item 179, wherein the constrained effective outer diameter is approximately equal to the constant effective outer diameter. (Item 181) Item 180. The graft of item 179, wherein compressive stress resulting from the continuous applied load maintains the support structure along the outflow region at the constrained effective outer diameter dimension. (Item 182) Item 180. The graft of item 179, wherein a reaction force comprising a radial expansion force applied to the support structure along the outflow region causes plastic deformation of the biocompatible layer. (Item 183) Item 180. The graft of item 179, wherein a reaction force comprising a radial expansion force applied to the support structure in the outflow region results in a decrease in compressive stress experienced by the support structure. (Item 184) Item 179. The graft of item 179, wherein following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to result in a plastically deformed biocompatible layer and a compressive stress experienced by the support structure that is less than the compressive stress experienced by the support structure prior to application of the reaction force. (Item 185) Item 179. The graft of item 179, wherein following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to provide a plastically deformed biocompatible layer. (Item 186) Item 179. The graft of item 179, wherein following application of a reaction force comprising a radial expansion force applied to the support structure in the outflow region, the graft reconfigures to cause the support structure to experience a residual compressive stress if there was previously a continuous compressive stress experienced by the support structure prior to application of the reaction force. (Item 187) Item 179. The graft of item 179, wherein a reaction force comprising a radial expansion force applied to the support structure in the outflow region reconfigures the support structure along the outflow region from the constrained effective outer diameter dimension to an expanded effective outer diameter dimension that exceeds the constrained effective outer diameter dimension along at least a portion of the support structure in the outflow region. (Item 188) Item 188. The graft of item 187, wherein the expanded effective outer diameter dimension exceeds the constrained effective outer diameter dimension by at least 1 mm along at least a portion of the support structure in the outflow region. (Item 189) Item 188. The graft of item 187, wherein the expanded effective outer diameter dimension of the support structure along the outflow region, after reconfiguration, exceeds the constrained effective outer diameter dimension by at least 1 mm along the entire portion of the support structure within the outflow region. (Item 190) The graft of any of items 169-189, wherein the conduit further comprises a second inflow opening. (Item 191) 191. The graft of any of items 169-190, wherein the longitudinal axis of the second inflow opening intersects the longitudinal axis of the at least one inflow opening at a non-parallel angle. (Item 192) Item 192. The graft of item 191, wherein the non-parallel angle comprises an angle of about 25° to 45°. (Item 193) Item 192. The graft of item 191, wherein the non-parallel angle comprises an angle of about 35°. (Item 194) 194. The graft of any of items 169-193, wherein the support structure is constructed from a shape memory alloy. (Item 195) 5. The graft of any of items 169-194, wherein the support structure is constructed from Nitinol. (Item 196) 196. The graft of any of items 169-195, wherein the support structure comprises a zigzag wire shape. (Item 197) 197. The graft of any of items 169-196, wherein the biocompatible layer comprises an expandable polymer. (Item 198) The graft of any of items 169-197, wherein the biocompatible layer comprises ePTFE. (Item 199) The graft of any of items 169-198, wherein the biocompatible layer further comprises a biocompatible outer layer. (Item 200) 199. The graft of any of items 169-199, wherein the biocompatible layer further comprises a biocompatible inner layer. (Item 201) The graft of any of items 169-200, wherein the biocompatible outer layer and the biocompatible inner layer encapsulate the support structure. (Item 202) The graft according to any of items 169-201, wherein the biocompatible layer is not a surface modifying coating. (Item 203) 1. A vascular graft comprising: a conduit having a wall, the conduit comprising: at least one inlet opening at an inlet end of the body region; an outlet opening at an outlet end of the outlet region opposite the at least one inlet opening; Equipped with the wall comprises a support structure and a biocompatible layer; prior to combination with the biocompatible layer to form the wall, the support structure has a plurality of effective outer diameters along its length, including a constant effective outer diameter along the body region and an effective outer diameter along the outflow region that is progressively larger at each section along the support structure that is progressively more distal from the at least one inflow opening; after combining with the biocompatible layer to form the wall, the support structure in the outflow region is under compressive stress resulting from a continuous applied load caused by the biocompatible layer that maintains the support structure along the outflow region at a constrained effective outer diameter dimension that does not progressively increase in each section along the support structure that is progressively more distal from the at least one inflow opening; After application of a reaction force to the support structure in the outflow region, the support structure in the outflow region reconfigures from the constrained effective outer diameter to an expanded effective outer diameter, at least a portion of which exceeds the constrained effective outer diameter by at least 1 millimeter. (Item 204) 1. A method for expanding the outflow end of an implanted graft, comprising: (a) a conduit having a wall, the conduit comprising: at least one inlet opening at an inlet end of the body region; an outlet opening at an outlet end of the outlet region opposite the at least one inlet opening; Equipped with wherein the wall comprises a support structure and a biocompatible layer; prior to combining with the biocompatible layer to form the wall, the support structure comprises a plurality of effective outer diameters, including a constant effective outer diameter along the body region and progressively larger effective outer diameters at each section along the support structure that is progressively more distal from the at least one inlet opening along the outflow region; after combining with the biocompatible layer to form the wall, the support structure in the outflow region is under compressive stress resulting from a continuous applied load caused by the biocompatible layer that maintains the support structure in the outflow region at a constrained effective outer diameter dimension that does not increase progressively with each segment along the support structure that is progressively more distal from the at least one inflow opening; identifying an implanted graft comprising a conduit; (b) applying a reaction force to a support structure in the outflow region, the application of the reaction force to the support structure in the outflow region reconfiguring the support structure along the outflow region from the constrained effective outer diameter dimension to an expanded effective outer diameter dimension that exceeds the constrained effective outer diameter dimension, thereby expanding the outflow region of the implanted graft; A method comprising: (Item 205) 25. The method of claim 204, wherein the outflow region comprises an outflow end that is collapsed, stenosed, or has persistent intimal thickening. (Item 206) The method according to any of items 204-205, wherein the collapsed, stenosed or persistently intimal thickened outflow end compromises the patency of the vessel in which the graft is implanted. (Item 207) The method of any of items 204-206, wherein the step of applying a counterforce comprises the step of expanding an expandable device within an outflow region of the implanted graft. (Item 208) The method of any of items 204-207, wherein prior to expansion of the expandable device, the expandable device is advanced to the outflow region. (Item 209) The method of any of paragraphs 204-208, wherein the expandable device is percutaneously introduced into the implanted graft prior to advancement of the expandable device to the outflow region. (Item 210) The method of any of items 204-209, wherein the expanded effective outer diameter dimension exceeds the constrained effective outer diameter dimension by at least 1 millimeter. (Item 211) The method of any of items 204-210, wherein the expanded effective outer diameter dimension exceeds the constrained effective outer diameter dimension by at least 1 millimeter along any portion of the support structure within the outflow region. (Item 212) 1. A method for expanding the outflow area of ​​an implanted graft, comprising: (a) a conduit having a wall, the conduit comprising: at least one inlet opening at an inlet end of the body region; an outlet opening at an outlet end of the outlet region opposite the at least one inlet opening; the wall comprises a support structure and a biocompatible layer; wherein the support structure within the outflow region is under compressive stress resulting from an applied load caused by the biocompatible layer. Providing an implanted graft comprising a conduit; (b) applying a reaction force to a support structure in the outflow region that reconfigures the support structure along the outflow region from a constrained effective outer diameter to an expanded effective outer diameter that exceeds the constrained effective outer diameter, thereby expanding the outflow end of the implanted graft; A method comprising: (Item 213) 1. A method of making a graft having an expandable outflow end, comprising: (a) providing a support structure comprising at least one inlet opening at an inlet end of a body region and an outlet opening at an outlet end of an outlet region opposite the at least one inlet opening, the support structure having a plurality of effective outer diameters comprising a constant effective outer diameter along a body region of the support structure and a gradually increasing effective outer diameter along the outlet region of the support structure; (b) combining the support structure with at least one biocompatible layer to form a conduit having a wall comprising the support structure and the at least one biocompatible layer; (c) inserting a mandrel into the outflow opening proximate an outflow end of the support structure; (d) constraining the gradually increasing effective outer diameter dimension of the support structure proximal to the outflow region using a compressive wrap such that a continuous compressive stress results from a continuous applied load caused by the biocompatible layer that maintains the support structure along the outflow region at the constant effective outer diameter dimension and a uniform constrained effective outer diameter dimension; (e) sintering the at least one biocompatible layer in a section within the outflow region; A method comprising: (Item 214) A support structure comprising an expandable support having a design and configuration as shown in the drawings. (Item 215) A support structure comprising an expandable support having a design and configuration as shown in FIG. 8E. (Item 216) A support structure comprising an expandable support having a design and configuration as shown in FIG. 9D. (Item 217) 1. A support structure comprising: Multiple rings R1 to R n wherein n is an integer and each ring R1 to R n a body having a pattern as shown in FIG. Multiple Rings R n+1 , Rn+2 , R n+3 where n is an integer and each ring R n+1 , R n+2 , R n+3 an expandable portion having a pattern as shown in FIG. 4 and having length dimensions D1, D2, and D3 larger than the previous ring; A support structure comprising: (Item 218) Each ring R1 to R n Item 218. The support structure of item 217, wherein each ring is connected to adjacent rings via a plurality of struts having the pattern shown in FIG. (Item 219) Ring R n+1 , R n+2 , R n+3 5. The support structure of any of items 217-218, wherein each of the rings is connected to an adjacent ring via a plurality of struts, each having the pattern shown in FIG. (Item 220) The plurality of rings R n+1 , R n+2 , R n+3 is a shape shown in FIG. 3A, a shape shown in FIG. 3B, a shape shown in FIG. 3C, a shape shown in FIG. 3D, a shape shown in FIG. 3E, a shape shown in FIG. 3F, a shape shown in FIG. 3G, a shape shown in FIG. 3H, a shape shown in FIG. 3I, a shape shown in FIG. 3J, a shape shown in FIG. 3K, a shape shown in FIG. 3L, a shape shown in FIG. 3M, a shape shown in FIG. 3N, a shape shown in FIG. 3O, 220. The support structure of any of items 217-219, configured to impart a shape selected from the group consisting of: and combinations and variations thereof. (Item 221) 1. A support structure comprising: Multiple rings R3 to R n wherein n is an integer and each ring R3 to R n a body having a pattern as shown in FIG. An expandable portion comprising rings R1 and R2, each ring having a pattern as shown in FIG. 11, where ring R1 has a length dimension D2 that is greater than the length dimension D1 of R2, and ring R2 is spaced apart from each of rings R3 to R4. n an expandable portion having a length dimension D1 that is greater than the length dimension of A support structure comprising: (Item 222) Each ring R3 to R n Item 222. The support structure of item 221, wherein each ring is connected to adjacent rings via a plurality of struts each having the pattern shown in FIG. (Item 223) 11. The support structure of any of items 221-222, wherein rings R1 and R2 are each connected to adjacent rings via a plurality of struts having the pattern shown in FIG. (Item 224) A graft comprising: a support structure having an expandable outflow region; and a biocompatible layer that constrains the expandable outflow region under a continuous radially inward compressive stress that enables the outflow region to expand in response to application of a radially outward counter force to the outflow region. (Item 225) 1. A method for expanding the outflow area of ​​an implanted graft, comprising: (a) A conduit having a wall, at least one inlet opening at an inlet end of the body region; an outlet opening at an outlet end of the outlet region opposite the at least one inlet opening; Equipped with wherein the wall comprises a support structure and a biocompatible layer; the support structure in the outflow region is under compressive stress resulting from an applied load caused by the biocompatible layer; Providing an implanted graft comprising a conduit; (b) reconfiguring the support structure along the outflow region from a constrained effective outer diameter to an expanded effective outer diameter that exceeds the constrained effective outer diameter, thereby applying a reaction force to the support structure in the outflow region that expands the outflow end of the implanted graft; A method comprising:

[0024] This patent or application contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0025] These and other features of the present invention will be more fully understood by reference to the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0026] [Figure 1] 1A and 1B are schematic diagrams of a vascular graft according to one embodiment of the present invention and another embodiment of the present invention, respectively. [Diagram 2] Figure 2A is a side view of an embodiment of a support structure of a vascular graft shown in Figure 1A according to one aspect of the present invention, illustrating the support structure prior to combination with a biocompatible layer. Figure 2B is a schematic diagram of an embodiment of a vascular graft shown in Figure 1A after combination of the support structure and a biocompatible layer shown in Figure 2A according to one aspect of the present invention. Figure 2C is a schematic diagram of an embodiment of a vascular graft shown in Figure 1A after expanding the outflow region of the support structure of the vascular graft shown in Figure 2B according to one aspect of the present invention. [Diagram 3] 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I, 3J, 3K, 3L, 3M, 3N, and 3O are wireframe diagrams showing various embodiments of "flared" outflow regions of support structures in accordance with aspects of the present invention. [Figure 4]Figure 4A is a schematic cross-sectional view of a support structure taken through line 68 in Figure 4B, and Figure 4B is a schematic illustration of an embodiment of a support structure useful for constructing a region proximal to the first region of the vascular graft shown in Figures 1A and 1B, according to one aspect of the present invention. [Diagram 5] FIGURE 5A is a cross-sectional view of a vascular graft similar to that shown in FIGURE 1A taken through section line 5-5 of FIGURE 1A. FIGURE 5B is a detail view taken about boundary 82 of FIGURE 5A in accordance with one aspect of the present invention. FIGURE 5C is a cross-sectional view of a vascular graft similar to that shown in FIGURE 1A taken through section line 5-5 of FIGURE 1A in accordance with one aspect of the present invention. FIGURE 5D is a cross-sectional view of a vascular graft similar to that shown in FIGURE 1A taken through section line 5-5 of FIGURE 1A in accordance with one aspect of the present invention. [Figure 6] Figure 6A is a side view of an embodiment of a support structure of a vascular graft shown in Figure 1B according to one aspect of the present invention, illustrating the support structure prior to combination with a biocompatible layer. Figure 6B is a schematic diagram of an embodiment of a vascular graft shown in Figure 1B after combination of the support structure and a biocompatible layer shown in Figure 6A according to one aspect of the present invention. Figure 6C is a schematic diagram of an embodiment of a vascular graft shown in Figure 1B after expanding the outflow region of the support structure of the vascular graft shown in Figure 6B according to one aspect of the present invention. [Figure 7] Figure 7A is a top view of an embodiment of a support structure of a vascular graft shown in Figure 1B, Figure 7B is a top wireframe view of a support structure of a vascular graft shown in Figure 7A, and Figure 7C is a side wireframe view of a support structure of a vascular graft shown in Figure 7B. [Figure 8A] FIG. 8A is a side view of an embodiment of a support structure similar to the vascular graft shown in FIG. 1A, illustrating the support structure prior to combination with a biocompatible layer, according to one aspect of the present invention. [Figure 8B] FIG. 8B is a schematic diagram of the embodiment of the vascular graft shown in FIG. 8A after combining a biocompatible layer with the support structure shown in FIG. 8A, according to one aspect of the present invention. [Figure 8C]FIG. 8C is a schematic illustration of the embodiment of the vascular graft shown in FIG. 8B after expanding the outflow region of the support structure shown in FIG. 8B, according to one aspect of the present invention. [Figure 8D] FIG. 8D is a side wireframe view of the support structure shown in FIG. 8C, according to one aspect of the present invention. [Figure 8E] FIG. 8E is a photograph of an embodiment of the support structure shown in FIGS. 8A through 8D, according to one aspect of the present invention. [Figure 8F] FIG. 8F is a schematic diagram of an embodiment of a support structure proximal to the inflow region of the vascular graft shown in FIGS. 8A, 8D, and 8E, according to one aspect of the present invention. [Figure 9A] FIG. 9A is a side view of an embodiment of a support structure for a vascular graft similar to the embodiment shown in FIG. 1B according to one aspect of the present invention, illustrating the support structure prior to combination with a biocompatible layer. [Figure 9B] FIG. 9B is a schematic diagram of the embodiment of the vascular graft shown in FIG. 1B after combining a biocompatible layer with the support structure shown in FIG. 9A, according to one aspect of the present invention. [Figure 9C] FIG. 9C is a schematic diagram of an embodiment similar to the vascular graft shown in FIG. 1B after expanding the outflow region of the support structure of the vascular graft shown in FIG. 9B, according to one aspect of the present invention. [Figure 9D] FIG. 9D is a photograph of an embodiment of a support structure shown in FIG. 9A, according to one aspect of the present invention. [Figure 9E] FIG. 9E is a photograph of an embodiment of a vascular graft shown in FIG. 9B, according to one aspect of the present invention. [Figure 9F] FIG. 9F is a photograph of an embodiment of a vascular graft shown in FIG. 9C with an extended lumen extending from the bifurcation, according to one aspect of the present invention. [Figure 9G] FIG. 9G is a photograph similar to FIG. 9F, further illustrating a boundary 84 that surrounds a portion of the graft at the bifurcation, according to one aspect of the invention. [Figure 9H]FIG. 9H is a schematic, representative, cross-sectional detail view of the embodiment of FIGS. 9B and 9C taken about boundary 84 of FIG. 9G, in accordance with an aspect of the present invention. [Figure 10] Figure 10A is a schematic illustration of an expandable device similar to the embodiment of Figure 9F used to expand the outflow region of a vascular graft, according to one aspect of the present invention, and Figure 10B is a detailed view taken around boundary 86 of Figure 10B, according to one aspect of the present invention. [Figure 11] FIG. 11 is a photograph demonstrating an expandable device used to expand the outflow region of a vascular graft, according to one aspect of the present invention. [Figure 12] FIG. 12 is a flow diagram depicting a method of expanding the outflow region of a vascular graft, according to one aspect of the present invention. [Figure 13] FIG. 13 is a flow diagram depicting a method of making a vascular graft, according to one aspect of the present invention. [Figure 14] 14A and 14B are photographs illustrating steps of a method of making a vascular graft according to one aspect of the invention. [Figure 15A] FIG. 15A is a schematic diagram of a vascular graft according to another embodiment of the invention, illustrating the support structure prior to combination with a biocompatible layer, according to one aspect of the invention. [Figure 15B] FIG. 15B is a schematic diagram of the embodiment of the support structure of FIG. 15A after a biocompatible layer has been added to the support structure, according to one aspect of the present invention. [Figure 15C] FIG. 15C is a schematic diagram of an embodiment of the vascular graft of FIG. 15B implanted in one or more vessels, according to one aspect of the present invention. [Figure 16A] FIG. 16A is a schematic diagram of a vascular graft according to another embodiment of the invention, illustrating the support structure prior to combination with a biocompatible layer, according to one aspect of the invention. [Figure 16B]FIG. 16B is a schematic diagram of the embodiment of the support structure of FIG. 16A after a biocompatible layer has been added to the support structure, according to one aspect of the present invention. [Figure 16C] FIG. 16C is a schematic diagram of an embodiment of the vascular graft of FIG. 16B implanted in one or more vessels, according to one aspect of the present invention. [Figure 17A] FIG. 17A is a schematic diagram of a vascular graft according to another embodiment of the invention, illustrating the support structure prior to combination with a biocompatible layer, according to one aspect of the invention. [Figure 17B] FIG. 17B is a schematic diagram of the embodiment of the support structure of FIG. 17A after a biocompatible layer has been added to the support structure, according to one aspect of the present invention. [Figure 17C] FIG. 17C is a schematic diagram of an embodiment of the vascular graft of FIG. 17B implanted in one or more vessels, according to one aspect of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] (Detailed Description) The present invention is directed to various embodiments of radially supported graft devices and / or stent grafts useful for various vascular access applications, including, but not limited to, facilitating vascular access in vascular bypass applications, facilitating treatment of atherosclerosis, and facilitating arteriovenous access for dialysis treatment. In exemplary embodiments, the devices of the present invention have expandable flared ends, bifurcated designs, and / or stent (i.e., radial support structure) patterns configured to facilitate vascular access and substantially sutureless and secure implantation of the device into the vasculature of a patient. Although the present invention is described with reference to the figures, it should be understood that many alternative forms may embody the invention. In addition, one skilled in the art may understand different ways to modify the disclosed parameters, such as size, shape, or type of elements or materials, in a manner that still retains the spirit and scope of the invention.

[0028] 1A through 17C, where like parts are designated by like reference numbers throughout, which illustrate exemplary embodiments of vascular grafts and methods of production and use thereof, in accordance with the present invention. In particular, these embodiments show vascular grafts (e.g., for anastomosis) having an expandable outflow region, for example, after implantation into a body passageway (e.g., blood vessel), to restore patency, and methods of production and use thereof.

[0029] A vascular graft 10 according to an exemplary embodiment of the present invention is illustrated in FIG. 1A. The vascular graft 10 is configured as a conduit 20 having a hollow body region 43 with an internal lumen 21 formed by a wall 30. The conduit 20 includes at least one inflow opening 32 at an inflow end 35 and an outflow opening 34 at an outflow end 36 in an outflow region 42 opposite the at least one inflow opening 32. The inflow end 35 and the outflow end 36 of the conduit 20 are in fluid communication with each other through the internal lumen 21 that is the defined conduit 20 and extends between the at least one inflow opening 32 and the outflow opening 34. The wall 30 of the conduit 20 is formed by a support structure 40 and a biocompatible layer 50. The support structure 40 may be any device configured to maintain vascular patency. An exemplary support structure 40 may include a stent. In one embodiment, the support structure 40 is an expandable structure and may be constructed from a shape memory alloy such as Nitinol. In an exemplary embodiment, the biocompatible layer 50, which may be configured as a cover, sheath, or sleeve, may at least partially or completely cover the exterior surface of the support structure 40. The support structure 40 may be separate from the biocompatible layer 50, adhered to the biocompatible layer 50, at least partially embedded within the material of the biocompatible layer 50, or any permutation of the foregoing. The support structure 40 along the outflow region 42 is under a continuous compressive stress (S) resulting from the biocompatible layer 50 resulting from a continuous applied load on the support structure 40. For example, the support structure 40 may be arranged to spring or resiliently impart a continuous radially outwardly directed force to the biocompatible layer 50, which in response imparts a continuous compressive stress to the support structure 40.

[0030] Figures 2A, 2B, and 2C show diagrams of the support structure 40 of the vascular graft 10 shown in Figure 1A prior to being combined with a biocompatible layer 50 to form a wall 30 (Figure 2A), after the support structure 40 and biocompatible layer 50 shown in Figure 2A have been combined to form a wall 30 (Figure 2B), and after the outflow region 42 of the support structure 40 of the vascular graft 10 shown in Figure 2B has been expanded (Figure 2C).

[0031] 2A , the support structure 40, prior to being combined with the biocompatible layer 50 to form the wall 30 of the conduit 20, has a variable outer diameter along the length of the support structure 40. As shown, the support structure 40 has a constant effective outer diameter dimension D along the body region 43, as discussed further below. c and an effective outer diameter dimension D 1 that increases along at least a portion of the outflow region 42 toward the outflow opening 34 and flares outwardly to give the outflow region a "flared" shape or appearance. inc This outwardly flared configuration of the support structure 40 allows for substantially sutureless attachment and retention of the stent graft 10 within the patient's vasculature. As shown in FIG. 2A, upon coating of the support structure 40 with a biocompatible layer 50, the flared outflow region 42 extends beyond the conduit 20, as shown in FIG. 2B, to a constant effective outer diameter dimension D along the length of the body region 43 and the outflow region 42. c 2C is a schematic diagram of an expanded effective outer diameter dimension D of the support structure 40 after an external expansion force is applied to the outflow region 42 of the support structure 40 in FIG. 2B. In an exemplary embodiment, the outflow region 42 is constructed from a shape memory alloy, such as Nitinol, that is expandable from its constrained state to achieve and maintain the expanded configuration in response to the application of an expansion force, such as a balloon catheter expansion. This shape memory support structure 40 may be self-expanding, but cannot assume its expanded state without balloon expansion due to the compressive stress applied by the biocompatible layer 50. FIG. 2C is a schematic diagram of an expanded effective outer diameter dimension D of the support structure 40 after an external expansion force is applied to the outflow region 42 of the support structure 40 in FIG. 2B. exp Shows.

[0032] 3A-3O show various exemplary embodiments of the outflow region 42 of the support structure 40, depicting various flared configurations. These illustrations represent a wireframe profile of the support structure 40, without depicting its strut pattern. Those skilled in the art may appreciate that several different strut patterns may be utilized, and all such patterns are considered to be within the depicted profile. With respect to FIGS. 3K-3O, those skilled in the art may additionally appreciate that the diameter of each support structure segment along the support structure 40 in the outflow region 42 may vary depending on the particular implementation. In the exemplary embodiments of FIGS. 3K and 3M, each support structure segment is generally constructed from a single zigzag ring (as described below) such that the support structure segments form a conduit having graduated increments of increasing diameter as they approach the outflow opening 34. In another exemplary embodiment, the support structure 40 may include a plurality of these stepwise increments at intervals of sufficient frequency such that a portion of the outflow region 42, i.e., the portion between the proximal and distal ends of the outflow region 42, appears to have a substantially uniform linear change in diameter (e.g., FIG. 3A), or alternatively, a curvilinear change in diameter rather than a step change in diameter (e.g., FIGS. 3F and 3I). In yet another exemplary embodiment, the increments may occur such that the effective outer diameter does not change along at least one section along the support structure 40 within the outflow region 42 (e.g., FIGS. 3B, 3C, 3G, 3J, 3L, 3M, 3N, and 3O). In certain exemplary embodiments, the increments may occur to combine any of the aforementioned configurations (e.g., FIGS. 3L, 3N). Those skilled in the art may readily envision other suitable flaring configurations that may be considered within the scope of the present invention.

[0033] 4, a wireframe design forming an exemplary support structure 40 structure of the outflow region 42 is illustrated. FIG. 4 shows a properly scaled illustration of the support structure 40, showing the precise relative proportions of the support structure pattern depicted therein, in a flat orientation. As shown, the support structure 40 is made up of a series of interconnected rings (e.g., R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35, R36, R37, R38, R40, R41, R42, R43, R44, R45, R46, R47, R48, R49, R50, R51, R52, R53, R54, R55, R56, R57, R58, R59, R60, R61, R62, R63, R64, R65, R66, R70, R71, R72, R73, R74, R75, R76, R77, R78, R79, R80, R81, R82, R82, R83, R84, R85, R86, R87, R88, R89, R90, R91, R92, R93, R94, R95, R96, R97, R98, R99, R100, R1101, R1202, R1303, R1404, R150, R1605, R1706 n , R n+1 , R n+2 , R n+3, where n=an integer representative value), each with a substantially zigzag shape with a series of peaks and valleys. Once the flattened wire frame is wound into a three-dimensional cylindrical configuration, the peaks or crests of each ring directly face and are aligned with the corresponding valleys of the adjacent rings, and vice versa. This arrangement of peaks and valleys is present throughout the length of the support structure 40, creating a flexible structure that allows the stent 20 to bend and redirect once implanted. FIG. 4 illustrates an exemplary strut or stent pattern for the support structure 40.

[0034] In the embodiment shown in FIG. 4 , the support structure 40 in the outflow region 42 has an effective outer diameter dimension D that is progressively larger at each section (D, D1, D2, D3) along the support structure 40 for each progressively more distal portion or section extending from the at least one inflow opening 32 to the at least one outflow opening 34. inc In this non-limiting example, the support structure 40 includes a series of interconnected rings (e.g., R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, n , R n+1 , R n+2 , R n+3 , where n=an integer representative value). As an example, in one embodiment, rings R1 and R2 of support structure 40 n Rings R1 and R2 are located in the body region 43 proximal to the outflow region 42, while rings R3, R4, and R5 are located in the outflow region 42, with R5 forming the edge of the outflow opening 34. n The rings in body region 43 may have the same size and dimension D. Meanwhile, the rings in body region 43 generally have the same size and dimension, with rings R3, R4, and R5 having gradually increasing ring widths (i.e., lengths of peaks and valleys) D1, D2, and D3. The effective outer diameter dimension of support structure 40 increases at each ring segment R as the width of each ring segment D increases. For example, the width D1 of ring segment R3 is greater than the width D1 of ring segment R4. n , so that the width D of the ring section R n, the width D2 of ring segment R4 exceeds the width D1 of ring segment R3, thereby increasing the effective outer diameter dimension of support structure 40 at ring segment R4, and the width D3 of ring segment R5 exceeds the width D2 of ring segment R4, thereby increasing the effective outer diameter dimension of support structure 40 at ring segment R5, relative to ring segment R3. The effective outer diameter dimension of this embodiment of support structure 40 within the outflow region 42 is thus progressively larger at each segment along the support structure 40 that is progressively more distal from the at least one inflow opening 32. With only three ring segments R1, R2, R3 with progressively increasing dimensions D1, D2, and D3, respectively, n+1 , R n+2 , and R n+3 , it should be understood that the outflow region 42 of the support structure 40 can include more (e.g., 4, 5, 6, etc.) or fewer (e.g., 2) ring segments R depending on the particular application, as can be appreciated by one of ordinary skill in the art.

[0035] As shown in the embodiment illustrated in FIGS. 3A-3O (discussed above), any particular section R (R n+1 , R n+2 , R n+3 ) is the constant effective outer diameter D c In such embodiments, the support structure 40 expands at locations within the outflow region 42 where the effective outer diameter dimension increases and does not expand at locations where the effective outer diameter dimension remains constant. In some embodiments, the support structure 40 may initially include a diameter of R n Due to the gradually increasing width D1 relative to the width D of the section R, for example, n+1 and then, for example, in section R n+1 and R n+23A-3O), the length of the horizontal section of the initial flaring or outflow region 42 can be varied as desired by increasing the width D1, or D2 and D3, respectively. In one embodiment illustrated in FIGS. 3A-3O (discussed above), any particular section R (R ) having a width D (D1, D2, D3) can be varied as desired by increasing the width D1, or D2 and D3, respectively. n+1 , R n+2 , R n+3 ) can have an effective outer diameter dimension that increases at a greater rate relative to the previous section R. In one embodiment illustrated in FIGS. 3A-3O (discussed above), any particular section R (R) having a width D (D1, D2, D3) can have an effective outer diameter dimension that increases at a greater rate relative to the previous section R. n+1 , R n+2 , R n+3 ) can have an effective outer diameter dimension that increases at a lesser rate relative to the previous section R. It should be understood by one skilled in the art that the flaring outflow region 42 can be configured to modify the size and / or shape of its flared features, so long as the effective outer diameter dimension of the support structure 40 prior to combining with the biocompatible layer 50 and forming the wall 30 increases along at least a portion of the outflow region 42. One skilled in the art will appreciate that the flaring features (e.g., size, shape, or angle) within the outflow region 42 can be configured to vary, in part, from each ring section R, respectively. n+1 , R n+2 , R n+3 It can be seen that the widths D1, D2, D3 of the

[0036] Ring section R (e.g., R1, R n , R n+1 , R n+2 , R n+3 Various dimensions D (e.g., D, D1, D2, D3) for the outer diameter of the support structure 40 are contemplated for the support structure 40. Table 1 below shows the effective outer diameter dimensions D in increasing order within the outflow region 42. inc 1 provides a non-limiting example of dimensions for manufacturing a support structure 40 having

[0037] [Table 1]

[0038] In the exemplary embodiment shown in Figures 8A-8G, the outlet region 42 has the same expandable configuration as shown in Figures 1A-2C and generally discussed above. The inlet region 44 of the present alternative stent graft 10 may have a prefabricated, pre-extended expansion configuration prior to implantation, as shown in Figures 8A-8G. In various views of the present stent graft embodiment, the support structure 40 has a prefabricated, pre-extended outwardly expanding inflow region 44 to maintain or improve graft patency along the inflow region 44. In these examples, the expansion shape or appearance is oriented in the opposite direction to the expansion shape or appearance at the outflow end 36. This prefabricated, pre-extended expansion configuration of the inflow region 44 facilitates friction fit attachment and positioning within the vasculature.

[0039] FIG. 8A shows a side view of the straight vascular graft shown in FIG. 1A, illustrating the expanded configuration of the inflow region 44 of the support structure 40 prior to combining with the biocompatible layer 50 and forming the wall 30. FIG. 8B shows a schematic diagram of the straight vascular graft shown in FIG. 1A, illustrating the prefabricated, pre-extended expanded configuration of the support structure 40 along the inflow region 44 and the expandable outflow region 42 after combining with the support structure 40 and biocompatible layer 50 shown in FIG. 8A and forming the wall 30. FIG. 8B shows the vascular graft after the inflow region 44 has been expanded. FIG. 8C shows a schematic diagram of the straight vascular graft shown in FIG. 1A, illustrating the expanded effective outer diameter dimension D of the support structure 40 along the outflow region 42. exp Figure 8D shows a side wireframe view of the support structure 40 shown in Figures 8A and 8D. Figure 8E is a photograph showing the actual construction of the support structure 40 shown in Figure 8A.

[0040] In particular, referring to FIG. 8E, the prefabricated, pre-expanded, spread-out shape or appearance of inlet region 44 is achieved by ring segments R1 and R2 of support structure 40 each having a different width D2, D1 from one another, and ring segments R3 to R4 each having a different width D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23, D24, D25, D26, D27, D28, D29, D30, D31, D32, D33, D34, D35, D36, D37, D38, D39, D40, D41, D42, D43, D44, D45, D46, nIt is demonstrated that this can be achieved by a similar design methodology as illustrated in FIG. 4, with the ring segments R (e.g., R1, R2, R3 through R n , where n=an integer) different widths D (e.g., D2, D1, D) define an effective outer diameter dimension D that provides a flared appearance to the support structure 40 along the outflow region 42. inc is granted.

[0041] The outflow region 42 of the support structure 40 may be constructed in the same manner as described above and shown in FIG. 4B. FIG. 8F shows a schematic diagram of a support structure 40 useful for the inflow region 44 according to an exemplary structure. This structure can be utilized for at least two purposes. In a first embodiment, the flared inflow region 44 is prefabricated prior to implantation to produce a pre-expanded, flared configuration. In another embodiment, the pre-expanded and flared configuration provides a locally increased inner diameter that provides space for receiving a lumen (e.g., as in a socket) separate from the biocompatible layer 50, but possibly constructed from the same base material as the biocompatible layer 50. For example, an extended lumen 51 having a thicker wall thickness than the layer 50 may be inserted into a socket constructed such that the inner luminal surface of the extended lumen 51 is substantially flush with, or at least approximately the same diameter as, the inner luminal surface of the conduit body portion 43.

[0042] 8F shows a scaled illustration of support structure 40 showing the precise relative proportions of the support structure pattern depicted therein. Each ring forming conduit body portion 43 is shown as R n and R3. The peaks or crests of each of these rings directly face and align with the corresponding valleys of an adjacent ring, with the struts connecting the adjacent rings building flexibility into the graft and facilitating in situ bending. The proximal inflow region 35 of the support structure 40 includes multiple rings, with the peaks or crests of ring R2 facing the peaks and crests of the adjacent ring R1, while the valleys of ring R2 directly face and align with the valleys of the adjacent ring R1, providing additional stiffness in the inflow region 35.

[0043] As shown in FIG. 8F , ring segments R1 and R2 located proximate to the inflow end 35 of the inflow region 44 of the support structure 40 are respectively connected to ring segments R3 to R4 located within the body region 43 of the support structure 40. n (n=integer) wider than the width D of ring segment R3. Providing ring segment R2 with a width D1 that is greater than the width D of ring segment R3 causes the wall 30 adjacent to ring segment R2 to flare outward, as illustrated by the angled R2 segment shown in FIG. 8D. The effective outer diameter dimension D of the inflow region 44 shown in this embodiment is inc consists of ring segment R1 with a constant effective outer diameter dimension along its width D2, as illustrated by the line extending along the longitudinal width of ring segment R1 shown in Figure 8D. However, it should be understood by one skilled in the art that the support structure 40 proximal to the inflow region 44 can be formed in any desired manner that maximizes patency of the inflow region while the vascular graft 10 is implanted within a body lumen.

[0044] 2B and 8B, schematic diagrams of the embodiment of vascular graft 10 shown in FIGS. 1A and 8A are shown depicting the generally uniform effective outer diameter dimension of support structure 40 after the support structure 40 and biocompatible layer 50 shown in FIGS. 2A and 8A are combined to form wall 30. Application of biocompatible layer 50 to the exterior surface of support structure 40 to form wall 30 places support structure 40 in the outflow region 42 under a continuous compressive radial stress S (e.g., radial compressive stress) resulting from a continuous applied load to support structure 40 by compressing biocompatible layer 50 against support structure 40. Generally, compressive stress S resulting from the continuous applied load in outflow region 42 exceeds compressive stress S0 resulting from an applied load in body region 43. One skilled in the art will recognize that compressive stress S resulting from a continuous radial applied load in outflow region 42 generally varies along the length of outflow region 42 as the effective outer diameter of support structure 40 in outflow region 42 changes. 2B and 8B, for example, the compressive stress S experienced by the support structure 40 resulting from a continuous applied load in the outflow region 42 gradually increases along the length of the support structure 40 as it approaches the outflow opening 34, i.e., the compressive stress S is greater at each section along the support structure 40 that is progressively more distal from the at least one inflow opening 32 at the inflow end 35. In this example, the compressive stress S is at a minimum S in the proximal area of ​​the outflow region 42. min and the effective outer diameter of the support structure 40 is such that the maximum compressive stress S max (prior to combining with biocompatible layer 50 to form wall 30), increases.

[0045] The compressive stress S causes elastic deformation of the support structure 40 in the outflow region 42. As will be appreciated by those skilled in the art, the degree of elastic deformation is a function of the compressive stress S resulting from the applied load posed by the biocompatible layer 50. In the embodiment shown in FIGS. 2B and 8B, the elastic deformation of the support structure 40 in the outflow region 42 occurs at a minimum compressive stress S min to maximum compressive stress S max3. As illustrated by the gradually increasing compressive stress in each section along the support structure 40 that is progressively more distal from the at least one inlet opening 32 .

[0046] In contrast to deformations that induce compressive stress S along the outflow region 42, the compressive stress S resulting from the applied load by the biocompatible layer 50 at the inflow distal end 35 and body region 43 results in only negligible elastic deformation of the support structure 40 along the body region 43. For clarity, the negligible compressive stress S experienced by the support structure 40 in the body region 43 resulting from the applied load caused by the biocompatible layer 50 on the support structure 40 is taken as the compressive stress S (S min From S max It should be understood by one of ordinary skill in the art that the amount of compressive stress S0 experienced by the support structure 40 in the outflow region 42 after being combined with the biocompatible layer 50 to form the wall 30 is generally negligible relative to the amount of compressive stress S0 experienced by the support structure 40 in the outflow region 42, which is ... negligible relative to the amount of compressive stress S0 experienced by the support structure 40 in the outflow region 42, which is negligible relative to the amount of compressive stress S0 experienced by the support structure 40 in the outflow region 42, which is negligible relative to the amount of compressive stress S0 experienced by the support structure 40 in the outflow region 42, which is negligible relative to the amount of compress As used herein, "substantial compressive stress" and "continuous compressive stress" are used interchangeably herein as would be understood by one of ordinary skill in the art and refer to the amount of compressive stress that accompanies or is associated with a change in the effective outer diameter of a portion or region of the support structure 40 that is subject to radial compressive stress S.

[0047] The combination of gradually increasing elastic deformation of the support structure 40 along the outflow region 42 and the absence of elastic deformation of the support structure 40 along the body region 43 provides the conduit 20 with a uniform effective outer diameter dimension, as illustrated in FIGS. 2B and 8B. This effective outer diameter dimension is referred to as a constant effective outer diameter dimension D along the body region 43. c and the constrained effective outer diameter dimension D along the outflow region 42 con As used herein, "constrained," in conjunction with "effective outer diameter," refers to the effective outer diameter of the support structure 40 along the outflow region 42 under compressive stress S, relative to the effective outer diameter of the support structure 40 along the outflow region 42 in the absence of compressive stress S prior to the support structure 40 and biocompatible layer 50 being combined to form the wall 30. The constrained effective outer diameter D con is the constant effective outer diameter D c It should be noted that the compressive stress S resulting from the continuous applied load is approximately equal to the effective outer diameter D of the constrained support structure 40 along the outflow region 42. con Maintain.

[0048] The elastic deformation of the support structure 40 along the outflow region 42 is reversible. The extent to which the elastic deformation of the support structure 40 along the outflow region 42 may be reversible will depend on the relative position of each ring segment R (e.g., R n+1 , R n+2 , R n+3 ) (e.g., D1, D2, D3) and the amount of reaction force applied to support structure 40 in outflow region 42. In this regard, the reaction force comprising a radial expansion force applied to support structure 40 in outflow region 42 causes plastic deformation of biocompatible layer 50. Such reaction force causes a decrease in compressive stress S experienced by support structure 40. In other words, as the reaction force increases the plastic deformation of biocompatible layer 50, the compressive stress S experienced by support structure 40 decreases, reversing the plastic deformation of support structure 40.

[0049] 2C and 8C, which show schematic diagrams of the embodiment of the vascular graft 10 shown in FIGS. 1A and 8A, with the expanded effective outer diameter dimension D of the support structure 40 of the vascular graft shown in FIGS. 2B and 8B after expanding the outflow region 42 of the support structure 40. exp As previously mentioned, the expanded effective outer diameter dimension D of the support structure 40 along the outflow region 42 is exp arises in response to application of a counter force comprising a radially expansive force. The present invention contemplates the use of any suitable means for applying such a radially expansive force, for example, by advancing a radially expandable device (e.g., balloon catheter 98) along the interior lumen of conduit 20 from at least one inflow opening 32 toward the outflow opening 34 to radially expand the expandable element. Other suitable means for applying such a radially expansive force will be apparent to those skilled in the art.

[0050] Those skilled in the art may further appreciate that the present invention contemplates the use of any amount of counterforce comprising a radially expanding force capable of overcoming the continuous applied load contributed by the biocompatible layer 50, thus allowing the outflow region 42 to expand. Preferably, the amount of counterforce comprising a radially expanding force used is an amount that results in atraumatic expansion of the outflow region 42 within the body lumen. Exemplary ranges of such counterforces may be apparent to those skilled in the art. However, for the sake of clarity, exemplary ranges of counterforces that may result in atraumatic expansion of the outflow region 42 in vivo or in situ include those counterforces resulting from the use of a semi-compliant balloon of no more than 2.5 mm (more preferably no more than 2.0 mm) across the effective outer diameter dimension of the outflow region 42.

[0051] Following application of a reaction force comprising a radially expanding force applied to the support structure 40 in the outflow region 42, the graft reconfigures to result in a plastically deformed biocompatible layer 50. In some cases, following application of the reaction force, the vascular graft 10 reconfigures to result in a plastically deformed biocompatible layer 50 and a compressive stress S experienced by the support structure 40 that is less than the compressive stress S experienced by the support structure 40 prior to application of the reaction force. In some cases, following application of the reaction force, the graft reconfigures to result in the support structure 40 experiencing a residual compressive stress S, where there was previously a continuous compressive stress S (e.g., a substantial compressive stress) experienced by the support structure 40 prior to application of the reaction force. As used herein, "residual compressive stress" refers to the amount of compressive stress S that remains in part as a result of recoil associated with the plastic deformation of the biocompatible layer 50 in response to application of a reaction force comprising a radially expanding force. Those skilled in the art will recognize that the amount of such residual compressive stress will depend on a variety of factors, including, for example, the magnitude of the radial expansion force and the amount of compressive stress S experienced by the support structure 40 due to the continuous applied load 50 caused by the biocompatible layer on the support structure 40 prior to application of the reaction force.

[0052] Still referring to FIGS. 2C and 8C, a reaction force comprising a radial expansion force applied to the support structure 40 in the outflow region 42 is applied to the constrained effective outer diameter dimension D shown in FIGS. 2B and 8B. con from the effective outer diameter dimension D constrained along at least a portion of the support structure 40 within the outflow region 42 con 2C and 8C. exp It is apparent that the support structure 40 within the outflow region 42 may be reconfigured to fit the constrained effective outer diameter dimension D con and the expanded effective outer diameter D exp The change in diameter between is about 0.5 mm and about 2.5 mm, or about 1 mm and about 2 mm, or even 1 mm and 1.5 mm. According to another exemplary embodiment, the expanded effective outer diameter dimension D exp is the effective constrained outer diameter dimension D along at least a portion of the support structure 40 within the outflow region 42 conOf course, the expanded effective outer diameter D exp As will be appreciated by those skilled in the art, the magnitude and duration of the radial expansion force and the length of the ring segment R (e.g., R n+1 , R n+2、 R n+3 Depending on various factors such as the length D (e.g., D1, D2, D3, etc.) or amount of constrained effective outer diameter D along at least a portion of the support structure 40 into the outflow region 42, con at least 1.10mm, at least 1.20mm, at least 1.30mm, at least 1.40mm, at least 1.50mm, at least 1.60mm, at least 1.70mm, at least 1.80mm, at least 1.90mm, at least 2.0mm, at least 2.10mm, at least 2.20mm, at least 2.30mm, at least 2.40mm, at least 2.50mm, at least 2.60mm, at least 2.70mm, at least 2.80mm, at least 2.90mm, at least 3.0mm, at least 3.1 According to another exemplary embodiment, the expanded effective outer diameter dimension D of the support structure 40 along the outflow region 42 can be greater than or equal to 5.0 mm, at least 3.20 mm, at least 3.30 mm, at least 3.40 mm, at least 3.50 mm, at least 3.60 mm, at least 3.70 mm, at least 3.80 mm, at least 3.90 mm, at least 4.0 mm, at least 4.10 mm, at least 4.20 mm, at least 4.30 mm, at least 4.40 mm, at least 4.50 mm, at least 4.60 mm, at least 4.70 mm, at least 4.80 mm, at least 4.90 mm, or 5.0 mm or greater. exp After reconfiguration, the constrained effective outer diameter dimension D along the entire portion of the support structure 40 within the outflow region 42 is con In an exemplary embodiment, the expanded effective outer diameter dimension D exp is the effective constrained outer diameter dimension D along the entire portion of the support structure 40 within the outflow region 42, as will be understood by those skilled in the art. conat least 1.10mm, at least 1.20mm, at least 1.30mm, at least 1.40mm, at least 1.50mm, at least 1.60mm, at least 1.70mm, at least 1.80mm, at least 1.90mm, at least 2.0mm, at least 2.10mm, at least 2.20mm, at least 2.30mm, at least 2.40mm, at least 2.50mm, at least 2.60mm, at least 2.70mm, at least 2.80mm, at least 2.90mm, at least 3.0mm, at least 3.1 0 mm, at least 3.20 mm, at least 3.30 mm, at least 3.40 mm, at least 3.50 mm, at least 3.60 mm, at least 3.70 mm, at least 3.80 mm, at least 3.90 mm, at least 4.0 mm, at least 4.10 mm, at least 4.20 mm, at least 4.30 mm, at least 4.40 mm, at least 4.50 mm, at least 4.60 mm, at least 4.70 mm, at least 4.80 mm, at least 4.90 mm, or 5.0 mm or greater.

[0053] The support structure 40 is configured such that the support structure 40 in the outflow region 42 changes to a constrained effective outer diameter dimension D in response to the application of a reaction force. con From the expanded effective outer diameter D exp The support structure 40 may be constructed from any material that allows the support structure 40 to be reconfigured to a shape memory alloy. According to one exemplary embodiment, the support structure 40 is constructed from a shape memory alloy. Exemplary shape memory alloys may be formed from combinations of metals, including, but not limited to, aluminum, cobalt, chromium, copper, gold, iron, nickel, platinum, tantalum, and titanium. According to one exemplary embodiment, the support structure 40 is constructed from Nitinol. Other shape memory alloys or other materials that may be used to construct the support structure 40 will be apparent to one of ordinary skill in the art.

[0054] Those skilled in the art will appreciate that the support structure 40 can be constructed with larger or smaller expandable portions. Those skilled in the art will also appreciate that the same methodology described above with respect to FIG. 3 for allowing the outflow region 42 to be expandable can be applied to make other portions of the support structure 40 (e.g., the body region) expandable.

[0055] The biocompatible layer 50 can be constructed from any biocompatible material. The material may further be substantially impermeable to fluids in some embodiments. The material may be substantially impermeable to fluids in some embodiments. The material may be substantially impermeable to fluids in some embodiments. The material may be substantially impermeable to fluids in some embodiments. The material may be substantially impermeable to fluids in some embodiments. The material may be substantially impermeable to fluids in some embodiments. con The continuous applied load can be caused to place the support structure 40 under sufficient continuous compressive stress (e.g., substantial compressive stress as defined herein) to maintain the support structure 40 in place. According to an exemplary embodiment, the biocompatible layer 50 comprises an expandable polymer. According to an exemplary embodiment, the biocompatible layer 50 comprises expanded polytetrafluoroethylene (ePTFE).

[0056] Generally, as shown in Figures 2B-2C and 8B-8C, the biocompatible layer 50 extends at least along the entire longitudinal length of the support structure 40 from the inflow end 35 to the outflow end 36. As will be appreciated by those skilled in the art, the biocompatible layer 50 may extend at least partially beyond or short of the inflow and outflow ends 35, 36 in accordance with acceptable manufacturing specifications. According to one exemplary embodiment, the biocompatible layer 50 may extend beyond the edges of the inflow and outflow ends 35, 36 and wrap around at least a portion of the interior surface of the support structure 40 in the form of a cuff.

[0057] 5A, 5B, 5C, and 5D, exemplary cross-sections of the vascular graft 10 shown in FIGS. 1A and 8A are shown depicting various ways in which the biocompatible layer 50 may be constructed. As can be seen from the exemplary embodiment of FIGS. 5A and 5C, the biocompatible layer 50 may comprise a biocompatible outer layer 54 and a separate biocompatible inner layer 55 spaced therefrom such that the outer layer 54 and the inner layer 55 are positioned on opposite sides of the support structure 40. As shown in FIGS. 5A and 5B, the biocompatible outer layer 54 and the biocompatible inner layer 55 may be constructed as separate layers of the same substrate wrapped continuously around the ends of the support structure 40, or alternatively, as two separate substrates (i.e., non-continuous) positioned on opposite sides of the support structure 40. In this example, either the biocompatible outer layer 54 or the biocompatible inner layer 55 may at least partially extend beyond and wrap around the edges of the inflow end 35 and outflow end 36 to form a cuff, for example, to minimize damage to surrounding tissue during deployment of the vascular graft 10. The circular portion of FIG. 5A, depicted as FIG. 5B, shows an exploded view of a portion of the biocompatible layer 50, illustrating how the biocompatible outer layer 54 and the biocompatible inner layer 55 conform to each other and to the support structure 40 as a result of the manner in which these layers may be applied, heated, sintered, or otherwise adhered onto or to the support structure 40, which methods are known to those skilled in the art. As shown in the exemplary embodiment in FIG. 5B, the biocompatible layer 50 can include the biocompatible outer layer 54 without the biocompatible inner layer 55. However, one skilled in the art may recognize that the biocompatible inner layer may serve to reduce the likelihood of stenosis or occlusion in the conduit 20 of the vascular graft 10 or to modify the fluid impermeability of the wall 30. Figures 5A-5D show an exemplary embodiment of the vascular graft 10 in which the biocompatible layer 50 encapsulates the support structure 40 with a biocompatible outer layer 54 and a biocompatible inner layer 55. In this example, the biocompatible outer layer 54 and the biocompatible inner layer 55 may be configured to encapsulate the support structure 40.All known methods and structures relating to the application or use of biocompatible layers, such as those described herein, are contemplated for use in conjunction with the present invention, and the formation of layers of the support structure is not limited by the specific illustrative examples provided herein.

[0058] In an exemplary embodiment, the biocompatible layer 50 is configured as a sheath, sleeve, or other covering that bonds and applies a compressive stress to the support structure 40. In an exemplary embodiment, the biocompatible layer 50, particularly the biocompatible outer layer 54, is adhesively bonded to the exterior surface of the support structure 40 to form a contracted and continuous covering over the support structure 40. The covering may be constructed from any suitable biocompatible material, particularly ePTFE, that is treated to apply a compressive force to the support structure 40. In an exemplary embodiment, the biocompatible layer 50, including the biocompatible outer layer 54 and / or the biocompatible inner layer 55, forms a hemocompatible covering that is configured and / or adapted to engage tissue and / or blood. It should be understood that the biocompatible layer 50 described herein is distinct from mere surface-modifying coatings, e.g., hydrophilic coatings, that are conventionally applied to medical devices for the purpose of delivering therapeutic agents or altering the surface properties of the medical device. It is contemplated that such surface modifying coatings, for example, coatings containing biological oils or fats as described in U.S. Patent No. 8,124,127 (incorporated herein by reference in its entirety), may be used to coat at least a portion of the surface of the support structure 40 or the biocompatible outer 54 and inner 55 layers, for reasons that will be apparent to one of ordinary skill in the art. For example, it may be desirable to coat at least a portion of the interior surface of the support structure 40 or the biocompatible inner layer 55 with a cured fish oil coating containing an anticoagulant therapeutic agent to prevent or minimize occlusion of the implanted graft.

[0059] 1B, an alternative embodiment of a vascular graft 10' is shown. While the example shown in FIG. 1A depicts a straight vascular graft 10, the vascular graft 10' of FIG. 1B may be designed to include a second inflow opening 33 to provide a bifurcated or generally T-shaped vascular graft 10', as depicted in the example shown in FIG. 1B. It should be understood that any description given regarding components common to both grafts 10 and 10' (i.e., those components identified with the same reference number) is generally applicable to both embodiments, unless otherwise indicated. As shown in FIG. 1B, the longitudinal axis of the second inflow opening 33 intersects the longitudinal axis of at least one inflow opening 32 at a non-parallel angle. As used herein, "non-parallel angle" means an angle (e.g., greater than 0°) at which the longitudinal axis of at least one inflow opening 32 is not parallel to the longitudinal axis of the second inflow opening 33. The non-parallel angle can be any non-parallel angle greater than 0° and less than 180° depending on the particular alignment required for graft implantation. Preferably, the non-parallel angle at which the longitudinal axis of the second inflow opening 33 intersects the longitudinal axis of the at least one inflow opening 32 is between about 25° and about 45°. According to one exemplary embodiment, the non-parallel angle at which the longitudinal axis of the second inflow opening 33 intersects the longitudinal axis of the at least one inflow opening 32 is about 35°.

[0060] Figures 6A, 6B, and 6C show various views of an embodiment of the support structure 40 of the branched vascular graft 110 structure shown in Figure 1B, illustrating the support structure 40 prior to combining with the biocompatible layer 50 to form the wall 30 (Figure 6A), after combining the support structure 40 and the biocompatible layer 50 shown in Figure 6A to form the wall 30 (Figure 6B), and after expanding the outflow region 42 of the support structure 40 covered with the biocompatible layer 50 of the vascular graft 110 shown in Figure 6B (Figure 6C). Those skilled in the art will appreciate that the description of the structure, function, and components of the straight vascular graft 110 previously described with respect to Figures 2A-5C are equally applicable to the branched vascular graft 110 shown in Figures 6A-6C.

[0061] 7A-7C, there are shown a top view (FIG. 7A), a top wireframe view (FIG. 7B), and a side wireframe view (FIG. 7C) of an embodiment of the support structure of the vascular graft shown in FIGS. 1B, 6A-6C, depicting a support structure with only at least one inflow opening 32 (see, e.g., FIG. 5A) and outflow opening 34 (see, e.g., FIG. 5C) before a second inflow opening 33 is attached to the graft body to form the branched vascular graft 10′ shown in FIGS. 1B and 6A-6C. As will be understood by those skilled in the art, the support structure 40 characterized in FIGS. 7A-7C includes all of the relevant features of the vascular graft 10′ shown in FIGS. 6A-6C. FIG. 7A shows an appropriately scaled illustration of the support structure 40 showing the precise relative proportions of the support structure and its strut / stent pattern. As shown in the exemplary embodiment in Figures 7A-7B, the support structure also includes a junction opening 37 to which a hollow branch conduit 99 is connected. The junction opening 37 and the second inlet opening 33 of the branch conduit 99 are in fluid communication with at least one of the inlet opening 32 and the outlet opening 34. As shown in the example in Figure 7A, the support structure 40 can terminate with one or more blunt ends 41, for example, to prevent or minimize damage to the biocompatible layer 50 caused by the support structure 40. The blunt ends 41 can be formed in a keyhole shape as shown in Figure 7A, or any other shape that allows the blunt ends 41 to prevent or minimize damage to the biocompatible layer 50 by the support structure 40.

[0062] To facilitate attachment of the branch conduit 99 and its second inlet opening 33 to the body region 43 of the support structure 40 at the junction opening 37, a recess 39 is provided in the contour of the body region 43 of the support structure 40, as in the exemplary embodiment illustrated in Figure 7C. The branch conduit may then be sewn, sintered, or otherwise attached to the body region 43 in the recess 39.

[0063] 9A-9H, various views of another embodiment of a branched vascular graft 410 are shown having a branched conduit 99 with a prefabricated and pre-expanded flared configuration at the second inflow opening 33 of the branched conduit 99 prior to implantation, similar to that shown in FIGS. 1B, 6A-6C. Except for this flared configuration, the vascular graft 410 may have the same structure, components, and configuration as the vascular graft 110 of FIGS. 1B and 6A-6C. This prefabricated and pre-expanded flared configuration anchors to the adjacent conduit body 43 and provides rigidity and structure. The flared ends may also facilitate vascular attachment and implantation. FIG. 9A shows a side view of the embodiment of the support structure 40 of the branched vascular graft 110 shown in FIGS. 1B, 6A-6C, illustrating the support structure 40 prior to combination with the biocompatible layer 50 and formation of the wall 30. 9B shows a schematic diagram of the embodiment of the branched vascular graft 110 shown in FIGS. 1B, 6A-6C after combining the support structure 40 and biocompatible layer 50 shown in FIG. 9A to form the wall 30. FIG. 9C shows a schematic diagram of the embodiment of the branched vascular graft 410 structure shown in FIGS. 1B and 6A-6C after expanding the outflow end 36 of the support structure 40 of the branched vascular graft 410 shown in FIG. 9B. FIG. 9D is a photograph showing a prototype of an example of the embodiment of the support structure 40 shown in FIG. 9A. FIG. 9E is a photograph of a prototype of an example of the branched vascular graft embodiment shown in FIG. 9B, showing the constrained effective outer diameter dimension D of the support structure 40 along the outflow region 42. con FIG. 9F is a photograph of a prototype of the example branched vascular graft embodiment shown in FIG. 9C, showing the expanded effective outer diameter dimension D of the support structure 40 along the outflow region 42. exp and an expanded effective outer diameter dimension D along the inlet region 44 proximal to the second inlet opening 33. exp Figure 9G is another photograph similar to Figure 9F, further illustrating boundary 94, which is used in Figure 9H to show diagrammatically as a detailed view of a representative cross section of the embodiment of Figures 9B and 9C.

[0064] 9G, the extension conduit 51 is shown assembled into the flared socket-like structure. Utilizing the flared second inflow opening 33, the extension conduit can connect to the luminal surface of the branch conduit 99 once the branch conduit is coated with a biocompatible layer on one or both of the inner and outer surfaces of the branch's support structure. When the extension conduit comprises a wall 89 that is thicker than the wall thicknesses 87 and 88 of the inner biocompatible layer 55 and the outer compatible layer 54, respectively, the flared inner diameter of the branch provides sufficient space for the extension conduit to have a diameter that is substantially the same as the inner diameter of all or at least the majority of the inner lumen diameter of the branch conduit.

[0065] Those skilled in the art will appreciate that in the exemplary embodiment shown in Figures 9A-9G, the various features of the branched vascular graft 110 and support structure 40 function in substantially the same manner as described in the relevant paragraphs above.

[0066] According to one exemplary embodiment, the vascular graft 110 is a conduit 20 having a wall 30 with at least one inflow opening 32 at an inflow end 35 in a body region 43 and at least one and an outlet opening 43 at an outlet end 36 in an outlet region 42 opposite the inlet opening 32, the wall 30 comprising a support structure 40 and a biocompatible layer 50, wherein prior to combination with the biocompatible layer 50 to form the wall 30, the support structure 40 has a constant effective outer diameter dimension D along a body region. c and an effective outer diameter dimension D along the outflow region that is gradually larger at each section along the support structure 40 that is gradually more distal from the at least one inflow opening 32. inc and wherein, after being combined with the biocompatible layer 50 to form the wall 30, the support structure 40 in the outflow region 42 is constrained to have a constrained effective outer diameter dimension D that is not gradually larger in each section along the support structure that is gradually more distal from the at least one inflow opening. con4, and where, after application of a reaction force to the support structure 40 within the outflow region 42, the outflow region 42 is under a continuous compressive stress S resulting from a continuous applied load induced by the biocompatible layer, which maintains the outflow region 42 at a constrained effective outer diameter dimension D. con from the effective outer diameter dimension D, at least a part of which is constrained con At least 1 mm greater than the expanded effective outer diameter D exp The conduit 20 is reconfigured into

[0067] The straight and branched or T-shaped vascular grafts of the present invention (e.g., grafts 10 and 110) can be used for a variety of applications, including, for example, for replacement or bypass of diseased vessels in patients suffering from occlusive or aneurysmal disease, in trauma patients requiring vascular replacement, for dialysis access, to improve flow dynamics and reduce arterialization pressure during surgical anastomosis or other vascular procedures routinely performed by medical practitioners, as would be apparent to one of ordinary skill in the art.

[0068] In operation, the vascular grafts of the present teachings (e.g., grafts 10 and 110) are deployed for implantation into a body passageway (e.g., a blood vessel). Embodiments of the present invention contemplate any operable method of safely and effectively deploying the vascular grafts 10 / 110 for implantation into a body passageway. Suitable methods will be apparent to the skilled medical practitioner. For example, one known method of deploying such grafts is the use of a sheath and a tear line or "rip cord". The graft is contained within one or more sheaths for delivery to a desired location, preferably in a compressed state such that the outer diameter of the sheath(s) is 2 millimeters or more smaller than the vessel in which the graft (or graft portion) is intended to be implanted. Once properly positioned, the cord is pulled, separating the sheath along the tear line, and the sheath is then uncoiled and removed from the graft, leaving the graft in place, due at least in part to the self-expanding qualities of the graft. The general method of placing a graft using a single sheath in this manner is well known in the art and therefore does not require further explanation.

[0069] Once implanted within a body passageway, the outflow region 42 of the vascular graft 10 can be expanded to maintain or restore graft patency even after extended durations (e.g., weeks, months, years) from the time of original implantation. For example, if a portion of the graft collapses (e.g., due to tissue ingrowth and eventual thrombosis formation), stenoses, or sustains intimal hyperplasia, patency can be restored by expanding the outflow region 42 of the vascular graft 10 according to the methods of the present invention described herein.

[0070] 10A and 10B are schematic illustrations of an expandable device used to expand the outflow region 42 of an embodiment of a vascular graft 10 comprising a branched structure, but may also be employed for non-branched structures. More specifically, FIG. 10B is a detailed view taken around boundary 86 in FIG. 10A. In the example shown in FIGS. 10A-10B, the expandable device comprises a balloon catheter 98 with a balloon 97. However, one skilled in the art will appreciate that any expandable device capable of applying a counter force comprising a radial expansion force may be used. FIGS. 10A-10B are also instructive with respect to placement of the graft 110 depicted in this embodiment.

[0071] 11 is a photograph demonstrating an expandable device 86 being used to expand the outflow region 42 of a vascular graft 110 having a branched structure. The expandable device would be equally applicable to straight vascular grafts such as vascular graft 10.

[0072] Those skilled in the art can readily envision a variety of methods for expanding the outflow region 42 of the vascular graft 10.

[0073] According to an exemplary embodiment, a method 100 for expanding an outflow region 42 of an implanted vascular graft 10 generally includes steps (a) identifying or providing 102 a vascular graft 10 having a support structure configured with an expanded outflow region 42 in accordance with any aspect of the present invention, and (b) applying a reaction force 108 to the support structure 40 in the expanded outflow region 42 to expand the outflow region 42.

[0074] In step 102, the implanted vascular graft 10 comprises a conduit 20 having a wall 30, the wall comprising at least one inflow opening 32 at an inflow end 35 of a body region 43 and an outflow opening at an outflow end of an outflow region 42 opposite the at least one inflow opening 32, the wall comprising a support structure 40 and a biocompatible layer 50, the support structure 40 in the outflow region 42 being under a compressive stress S resulting from an applied load induced by the biocompatible layer 50. In step 108, applying a reaction force to the support structure 40 in the outflow region 42 comprises applying a constrained effective outer diameter dimension D con From the above, the effective outer diameter D con Expanded effective outer diameter D exp vascular graft 10. The vascular graft 10 may be implanted in a vascular graft configuration that is adapted to remodel the support structure 40 within the outflow region 42, thereby expanding the outflow region 42 of the implanted vascular graft 10.

[0075] FIG. 12 shows a flow diagram depicting an exemplary embodiment of a method 100 for expanding the outflow region 42 of a vascular graft 10, according to one aspect of the present invention.

[0076] As shown in the exemplary embodiment in Figure 12, a method for expanding the outflow region 42 of an implanted vascular graft 10 includes steps 102 through 108. Step 102 includes (a) identifying an implanted vascular graft 10 as described herein. Step 108 is performed to expand the implanted vascular graft 10 identified in step 102. Step 108 includes (b) applying a reaction force to a support structure 40 in the outflow region 42 in accordance with the detailed description herein, thereby expanding the outflow region 42 of the implanted vascular graft 10.

[0077] It should be understood that the expandable outflow region 42 may be expanded at any time after implantation, but in practice, the outflow region is advantageously expanded when the outflow region 42 is collapsed or stenosed, or has persistent intimal thickening, in which case the collapsed, stenosed, or persistent intimal thickening outflow region 42 would compromise the patency of the vessel in which the implantable vascular graft 10 is implanted.

[0078] In an exemplary embodiment, the step of applying a counterforce includes expanding an expandable device in the outflow region 42 of the implanted vascular graft 10. In an exemplary embodiment, prior to expanding the expandable device (step 108), the expandable device is advanced to the outflow end (step 106).

[0079] In an exemplary embodiment, the expandable device is percutaneously introduced into the implanted graft (step 104) prior to advancing the expandable device to the outflow region (step 106). In an exemplary embodiment, after expanding the expandable device 10, the expandable device is removed according to step 110.

[0080] In an exemplary embodiment, the expanded effective outer diameter dimension D exp is the constrained effective outer diameter D con In another exemplary embodiment, the expanded effective outer diameter dimension D exp is the constrained effective outer diameter dimension D along any portion of the support structure 40 within the outflow region 42 con at least 1 millimeter.

[0081] Contemplated herein are various methods for making the vascular graft 10 disclosed herein.

[0082] FIG. 13 is a flow diagram depicting an exemplary method 200 of making a vascular graft 10 according to one aspect of the present invention.

[0083] In an exemplary embodiment, a method 200 of making a vascular graft 10 having an expandable outflow region includes steps 202 through 209. In the example shown in FIG. 13, the method 200 begins with (a) providing a support structure (step 202) comprising at least one inflow opening 32 at an inflow end 35 of a body region 43 and an outflow opening 34 at an outflow end 36 of the outflow region 42 opposite the at least one inflow opening 32 in accordance with the detailed description provided herein. The support structure 40 is sized through the use of various mandrels to provide a gradually increasing effective outer diameter dimension D along the outflow region 42 of the support structure. inc In addition, the support structure 40 has a constant effective outer diameter dimension D along the body region 43. c It should be understood by one of ordinary skill in the art that the support structure 40 provided in step 202 can include any support structure 40 contemplated herein, including the embodiments shown in Figures 2A, 5A, 7A, and 8A, which may include inflow region 44 or outflow region 42 with the flared configurations illustrated in Figures 3A-3O, or any combination thereof.

[0084] Once the support structure 40 is provided in step 202, the method 200 proceeds to step 204, which includes (b) combining the support structure 40 with at least one biocompatible layer 50 to form a conduit 20 having a wall 30 comprising the support structure 40 and the at least one biocompatible layer 50.

[0085] After combining the support structure 40 and the biocompatible layer 50 in step 204, the method proceeds to step 206, which includes (c) inserting a mandrel into the outflow opening 34 proximal to the outflow end 36 of the support structure 40.

[0086] Once the mandrel is inserted into the outflow opening 34, the method further comprises: (d) applying a continuous compressive stress S to the support structure 40 along the outflow region 42 to a constant effective outer diameter dimension D c and the substantially uniform effective outer diameter D con2. The support structure 40 may be configured to have a gradually increasing effective outer diameter dimension D along the outflow region 42 thereof, for example by using a compression wrap, resulting from a continuous applied load caused by the biocompatible layer 50, which maintains the outer diameter dimension D along the outflow region 42 of the support structure 40 at a constant rate. inc Proceed to step 208, which includes constraining

[0087] To conform the biocompatible layer 50 to the support structure 40, the method includes a step 209 of (e) sintering the biocompatible layer 50 in a section within the outflow region 42.

[0088] FIG. 14A is a photograph illustrating step 206 of a method 200 of making a vascular graft 10 according to one aspect of the present invention, in which a mandrel is inserted into the outflow end 36 of the vascular graft 10 prior to constraining the effective outer diameter dimension along the outflow end 40 of the support structure using compression wrapping.

[0089] FIG. 14B is a photograph illustrating step 206 of a method 200 of making a vascular graft 10 according to one aspect of the present invention, in which compression wrapping is used to constrain the effective outer diameter dimension along the outflow end of the support structure 40.

[0090] In another exemplary embodiment of the invention, a vascular graft 510 is illustrated in Figures 15A-C. Graft 510 is formed by a pair of branch graft subassemblies 302a and 302b (collectively, "branch subassemblies 302") arranged as mirror images of one another and connected by an extending conduit 51. Each of the branch subassemblies 302 may be arranged as illustrated, similar to branch vascular graft 110. As discussed in more detail with respect to Figures 16A-16C and 17A-17C, further vascular graft embodiments can be formed by replacing one or both of the branch subassemblies 302 with a graft subassembly similar to graft 10. Thus, components of graft 510 similar to those of grafts 10 and / or 110 (e.g., conduit 20, wall 30, support structure 40, biocompatible layer 50, etc.) are correspondingly given the same reference numbers as used with respect to the foregoing discussion of grafts 10 and 110.

[0091] 15A illustrates a bifurcated subassembly without a biocompatible layer 50, while FIG. 15B illustrates a bifurcated subassembly, where both the biocompatible layer 50 and the extending lumen 51 establish a continuous conduit between the subassemblies. In various embodiments, the extending lumen 51 may be a multi-layer laminate construction of ePTFE and have a thickness 89 that exceeds the thicknesses of the inner layer 55 and the outer layer 54 of the biocompatible layer 50.

[0092] As illustrated in FIG. 15C, the branch subassemblies 302a and 302b are insertable into the first vessel portion 306a and the second vessel portion 306b (collectively, vessel portion 306), respectively. The conduit section 51 is arranged as a luminal structure that provides fluid communication, e.g., blood flow, between the branch subassembly 302 and thus the vessel portion 306. Due to both branches of the subassembly 302, at least a portion of the blood flow, i.e., blood flow that is not diverted into the conduit section 51, may also continue through and beyond the subassembly 302. The wall 30 of the conduit section 51 may be unreinforced, i.e., not include the support structure 40, but only include the biocompatible layer 50. It should be understood that the conduit section 51 may be of any desired length. For example, relatively shorter lengths may be used in some embodiments, e.g., to bridge or bypass a blockage in a blood vessel, while relatively longer lengths are used in other embodiments, e.g., to connect an artery and a vein to aid in dialysis. In one embodiment, conduit section 51 is about 20 mm to 150 mm, although other lengths are also possible.

[0093] It should be understood that graft 510 may be used in embodiments where vessel 306 is a different portion of the same vessel, or where vessel portions 306 are portions of different vessels. For example, when vessel portions 306 are portions of the same vessel, graft 510 may be used to create a bypass of a section of the vessel located between vessel portions 306a and 306b. An obstruction, such as, for example, plaque buildup, may completely or partially impede or block blood flow within a patient's blood vessel. In this example, graft 510 may thus be placed such that when subassembly 302 is placed in the blood vessel on either side of the obstruction, conduit sections 51 provide a bypass of the obstruction.

[0094] As another example, in one embodiment, one of the vessel portions 306 (e.g., vessel 306a) is part of an artery and the other of the vessel portions (e.g., vessel 306b) is part of a vein. In this manner, the conduit section 51 diverts a portion of the blood flowing through the artery into the vein. For example, this embodiment may be particularly useful in that the conduit section 51 provides a suitable target to assist the patient in undergoing dialysis, e.g., blood may be diverted between an artery and a vein where it is removed from and reinjected into the conduit section 51, thus avoiding unnecessary damage to the patient's vascular system that may result from repeated dialysis treatments. In such an embodiment, the ability of the conduit section 51 to seal after needle puncture is improved relative to the properties of the vascular graft 510, which may be covered by the thinner material used in the conduit section 51.

[0095] Vascular graft 610 is illustrated in Figures 16A-16C and is generally similar to graft 510, including a pair of graft subassemblies 312a and 312b (collectively, "subassemblies 312") connected together, for example, by conduit section 51. Unlike graft 510, in which both subassemblies 302 are similar to branched graft 110 of Figure 1B, subassembly 312b of graft 610 is generally a straight graft subassembly similar to straight vascular graft 10 of Figure 1A, while subassembly 312a is a branched graft subassembly similar to graft 110. Note that due to the lack of branching of subassembly 312b in this embodiment, blood flow through vessel portion 306b may be blocked or impeded by subassembly 312b. That is, all or most of the blood flow through vessel portion 306b in the direction from subassembly 312b to subassembly 312a may be diverted through conduit section 51, instead of continuing through vessel portion 306b. Thus, graft 610 is particularly advantageous in embodiments where blood flow through vessel portions 306b on either side of subassembly 312b is not necessary, such as, for example, when vessel portions 306 are part of the same vessel and an occlusion exists therebetween and thus bypass of the occlusion is desired.

[0096] Vascular graft 710 is generally similar to grafts 510 and / or 610 illustrated in FIGS. 17A-17C, including, for example, a pair of graft subassemblies 322a and 322b (collectively, "subassemblies 322") connected together by conduit section 51. Like subassembly 312b of graft 610, both subassemblies 322 are straight graft subassemblies, similar to graft 10 without branches. For this reason, like subassembly 312b, both subassemblies 322 may block or impede blood flow through the individual vessel segments 306 into which they are inserted. Graft 710 may thus be particularly useful in embodiments in which an occlusion exists between vessel segments 306 and thus bypass of that occlusion is desired.

[0097] It should be understood that subassemblies 510, 610, and 710 may include tapered, trumpet-shaped, or flared inflow and / or outflow regions in accordance with the foregoing description thereof. That is, support structure 40 within subassemblies 510, 610, and / or 710 may be arranged and constructed from Nitinol or other shape memory material, or otherwise configured to naturally transition to a radially expanded shape. Additionally, support structure 40 may be further radially expanded by use of an inflatable balloon 97 or other device inserted within support structure 40, similar to the disclosure hereinabove.

[0098] Numerous modifications and alternative embodiments of the present invention may be apparent to those skilled in the art in light of the foregoing description. This description is therefore to be construed as illustrative only, and is for the purpose of teaching those skilled in the art the best mode for carrying out the invention. Details of construction may vary substantially without departing from the spirit of the invention, and the exclusive use of all modifications that come within the scope of the appended claims is reserved. Although embodiments have been described herein to enable clear and concise writing, it is intended and should be understood that the embodiments may be variously combined or separated without departing from the invention. It is intended that the present invention be limited only to the extent required by the appended claims and the rules of applicable law.

[0099] It is also to be understood that the following claims encompass not only all the general and specific features of the invention described herein, but also all descriptions of the scope of the invention that may literally be found therein.

Claims

1. 1. A method for producing a graft, the graft comprising: a conduit having a wall, the conduit comprising: a first inflow region having a first inflow end and a second inflow region having a second inflow end, the first and second inflow regions meeting together at an inflow junction in fluid communication with an elongated expandable outflow region opposite the first inflow region, the outflow region having an outflow end; a first inlet opening disposed at a first inlet end of the first inlet region, a second inlet opening disposed at a second inlet end of the second inlet region, and an outlet opening disposed at an outlet end of the outlet region; Equipped with wherein the wall comprises a support structure and a biocompatible layer; the support structure along at least a portion of the elongated expandable outflow region is under compressive stress resulting from an applied load caused by the biocompatible layer on the support structure; and a length of the elongated expandable outflow region is greater than twice the length of either the first inflow region or the second inflow region; In the method, the support structure along the elongated expandable outflow region has an expanded configuration prior to combining with the biocompatible layer to form the wall; The method, wherein the support structure along the elongated expandable outflow region contracts and does not have an expanded shape due to compressive stress applied by the biocompatible layer after combining with the biocompatible layer and forming the wall.

2. The method of claim 1 , wherein the elongated expandable outflow region has a length that is greater than a length of either the first inflow region or the second inflow region.

3. The method of claim 1 , wherein the length of the conduit between the inlet junction and the outlet end is at least about 100 millimeters.

4. 2. The method of claim 1, wherein a compressive stress resulting from a continuous applied load in the elongated expandable outflow region exceeds a compressive stress resulting from a continuous applied load in either the first inflow region or the second inflow region.

5. 2. The method of claim 1, wherein the compressive stress experienced by the support structure resulting from successive applied loads within the elongated expandable outflow region gradually increases in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the one or more initial sections.

6. The method of claim 1 , wherein compressive stress experienced by the support structure resulting from a continuous applied load within the elongated, expandable outflow region causes elastic deformation of the support structure within the elongated, expandable outflow region.

7. 7. The method of claim 6, wherein the elastic deformation of the support structure within the outflow region increases in one or more initial sections along the support structure before becoming substantially constant across each section progressively more distal from the one or more initial sections.

8. The method of claim 6 , wherein the elastic deformation of the support structure within the elongated expandable outflow region is reversible.

9. 2. The method of claim 1, wherein reversing the elastic deformation of the support structure within the elongated expandable outflow region expands a diameter of the support structure within the elongated expandable outflow region to a diameter greater than an uncompressed diameter of the support structure that is not under compressive stress resulting from a continuous applied load within the elongated expandable outflow region.

10. 2. The method of claim 1, wherein the support structure has a plurality of effective inner diameter dimensions prior to combining with the biocompatible layer and forming the wall, and the support structure has a substantially uniform effective inner diameter dimension after combining with the biocompatible layer and forming the wall.

11. The method of claim 1 , wherein the longitudinal axis of the second inflow region intersects the longitudinal axis of the first inflow region at a non-parallel angle.

12. The method of claim 11 , wherein the non-parallel angle comprises an angle between about 25° and 45°.

13. The method of claim 11 , wherein the non-parallel angle comprises an angle of approximately 35°.

14. 12. The method of claim 11, wherein the second inflow region meets together at the inflow junction with the first inflow region such that the first inflow region and the second inflow region are not perpendicular to one another.

15. The method of claim 1 , wherein the support structure is constructed from a shape memory alloy.

16. The method of claim 1 , wherein the support structure is constructed from Nitinol.

17. The method of claim 1 , wherein the biocompatible layer comprises an expandable polymer.

18. The method of claim 1 , wherein the biocompatible layer comprises ePTFE.

19. The method of claim 1 , wherein the biocompatible layer further comprises a biocompatible outer layer.

20. The method of claim 19 , wherein the biocompatible layer further comprises a biocompatible inner layer.

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