US20230043946A1 - Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls - Google Patents
Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls Download PDFInfo
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- US20230043946A1 US20230043946A1 US17/970,332 US202217970332A US2023043946A1 US 20230043946 A1 US20230043946 A1 US 20230043946A1 US 202217970332 A US202217970332 A US 202217970332A US 2023043946 A1 US2023043946 A1 US 2023043946A1
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- conduit
- chamber
- graft
- cannulation
- end portion
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
- A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
- A61M1/3621—Extra-corporeal blood circuits
- A61M1/3653—Interfaces between patient blood circulation and extra-corporal blood circuit
- A61M1/3655—Arterio-venous shunts or fistulae
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
- A61M39/02—Access sites
- A61M39/0247—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
- A61M39/02—Access sites
- A61M39/0247—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body
- A61M2039/0258—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body for vascular access, e.g. blood stream access
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
- A61M39/02—Access sites
- A61M39/0247—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body
- A61M2039/027—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body having a particular valve, seal or septum
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
- A61M39/02—Access sites
- A61M39/0247—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body
- A61M2039/0276—Semi-permanent or permanent transcutaneous or percutaneous access sites to the inside of the body for introducing or removing fluids into or out of the body
Definitions
- This invention relates to grafts and, more particularly, to arteriovenous grafts for dialysis.
- Dialysis treatment of individuals suffering from renal failure requires that blood be withdrawn and cycled through a dialysis machine that performs the function of the failed kidneys. This process, termed hemodialysis, must be repeated at a regular interval (e.g., three times per week) and thus requires repeated punctures using dialysis needles. Relatively large gauge needles are required to promote the high flow rates required during dialysis. Frequent puncturing of autogenous arteriovenous access as well as prosthetic arteriovenous access with large bore needles can cause trauma, conduit degeneration, hematoma formation, pseudoaneurysm formation, loss of patency, or even hemorrhage and exsanguination.
- a common technique to provide vascular access for hemodialysis therefore, is to connect a prosthetic graft or shunt between an artery and a vein in, for example, the upper or lower extremity.
- a prosthetic graft or shunt between an artery and a vein in, for example, the upper or lower extremity.
- patient complexity may also warrant access placement on the chest or abdominal wall.
- Conventional arteriovenous grafts are often constructed of a polymeric material such as expanded polytetrafluoroethylene (ePTFE) or polyetherurethaneurea.
- a significant mode of failure of AVGs is related to a traumatic cannulation with the dialysis needle. This may occur as the needle traverses the anterior wall of the AVG and then continues through the posterior wall (or a sidewall) of the graft.
- This type of trauma causes a defect in the posterior and/or side wall of the graft and often results in hematoma formation which can ultimately lead to graft thrombosis (i.e., the formation of a blood clot inside the graft, obstructing the flow of blood therethrough) by external compression of the graft and ultimate graft failure.
- ePTFE graft material
- graft material such as ePTFE
- ePTFE grafts are generally not self-sealing when punctured and usually require implantation three, four or more weeks prior to puncture to allow for graft incorporation (a layer of fibrotic tissue that attaches to the outside surface of the graft).
- the layer of fibrotic tissue may prevent leakage of blood through the wall of the graft upon withdrawal of the dialysis needles and if cannulated before this time could lead to hematoma formation between the graft and surrounding tissue.
- U.S. Pat. No. 6,146,414 to Gelman the disclosure of which is incorporated herein in its entirety, describes tube grafts having expanded regions and shields at posterior portions of the expanded regions.
- the shields have added rigidity relative to the tube to thereby signal to the operator when the needle tip hits a shield during cannulation.
- the shields are either incorporated into the tube graft or are added as a separate component during assembly, thereby adding complexity to the manufacturing process.
- the Gelman patent describes that the shields may be rigid or semi-rigid but only describes straight grafts (i.e., grafts without curvature).
- Substantially rigid shields would require that the grafts described in the Gelman patent be kept in a generally straight configuration, and such a configuration may be difficult or impossible to use at many AVG implantation sites, such as forearms and upper arms.
- Semi-rigid shields may allow for some bending of the graft to accommodate placement in these areas, but would reduce or eliminate the capability of the shield to prevent needle penetration through the shield or warn the operator of impending penetration. Also, bending of grafts employing semi-rigid shields could weaken the graft and/or disrupt flow characteristics for blood flowing therethrough.
- the Gelman patent does not recognize the need for a self-sealing graft or a portion thereof.
- arteriovenous grafts configured to be implanted in a subject (e.g., in an upper or lower extremity of a subject) with puncture resistant posterior walls and side walls.
- arteriovenous grafts may include self-sealing ports at the anterior surfaces of the graft.
- Such designs may help prevent traumatic cannulations and/or graft degeneration so as to lead to higher patency rates for arteriovenous grafts, decrease the risk of hemorrhage or infection for hemodialysis patients, and reduce overall vascular access related healthcare costs.
- Embodiments of the invention are directed to an arteriovenous dialysis access graft configured to be implanted in a subject.
- the arteriovenous graft includes at least one flexible conduit having first and second end portions, wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion.
- the AVG includes at least one cannulation chamber positioned between the first end portion and the second end portion of the at least one conduit.
- the at least one chamber includes: an elongated housing having an inlet at a first end thereof and an outlet at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port; a self-sealing material extending across the cannulation port; and a longitudinal passageway defined by the housing and the self-sealing material that extends from the inlet to the outlet of the housing.
- the housing of the at least one chamber is formed of a substantially rigid material such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port, the needle is inhibited or prevented from extending through the posterior or the side walls of the housing.
- the at least one chamber comprises a plurality of chambers.
- the at least one conduit extends through the longitudinal passageway of the chamber(s).
- the at least one conduit comprises first and second flexible conduits.
- Each conduit has a first and second end. The first end of the first conduit is configured to connect to the artery of the subject and the second end of the first conduit is connected to the inlet of the chamber; the first end of the second conduit is configured to connect to the vein of the subject and the second end of the second conduit is connected to the outlet of the of the chamber.
- the at least one cannulation chamber comprises first and second cannulation chambers and the at least one conduit comprises first, second and third flexible conduits, with each conduit having a first and second end.
- the first end of the first conduit is configured to connect to the artery of the subject and the second end of the first conduit is connected to the inlet of the first chamber;
- the first end of the second conduit is configured to connect to the vein of the subject and the second end of the second conduit is connected to the outlet of the of the second chamber;
- the first end of the third conduit is connected to the outlet of the first chamber and the second end of the third conduit is connected to the inlet of the second chamber.
- At least one of the first and second chambers is curved such that the longitudinal passageway has an arc angle.
- the arc angle may be between about 5 and about 45 degrees to accommodate placement in an upper arm of the subject.
- the arc angle may be between about 5 degrees and about 60 degrees to accommodate placement in a forearm or lower extremity of the subject.
- the self-sealing material may be formed of a stretchable material such as silicone or polyurethane.
- the conduit(s) may be formed of a biocompatible polymeric material such as ePTFE.
- the chamber housing(s) may be formed of a biocompatible material such as titanium or a rigid polymer. Each chamber housing material may provide tactile and/or audible feedback to an operator that the dialysis needle has contacted an interior portion of the posterior wall or one of the side walls.
- FIG. 1 is a schematic illustration of an arteriovenous graft (AVG) according to some embodiments.
- FIG. 2 is an exploded view of the AVG of FIG. 1 according to some embodiments.
- FIG. 3 is a side view of a cannulation chamber of the AVG of FIG. 1 according to some embodiments.
- FIG. 4 is a cross-section view of a cannulation chamber of the AVG of FIG. 1 according to some embodiments.
- FIG. 5 is a top view of a curved cannulation chamber for use with the AVG of FIG. 1 according to some embodiments.
- FIG. 6 is a schematic illustration of the AVG of FIG. 1 implanted in an upper extremity (forearm) of a subject according to some embodiments.
- FIG. 7 is a top view of the AVG of FIG. 1 with a member comprising self-sealing material extending across the each of the cannulation chambers according to some embodiments.
- FIGS. 8 A- 8 C illustrate cross-section views of one of the cannulation chambers of FIG. 7 according to various embodiments.
- FIG. 9 A is bottom view of a cannulation chamber for use with the AVG of FIG. 1 according to some embodiments.
- FIG. 9 B is a cross-sectional view of the cannulation chamber of FIG. 9 A according to some embodiments.
- FIG. 10 A is an end view of a cannulation chamber for use with the AVG of FIG. 1 according to some embodiments.
- FIG. 10 B is a cross-sectional view of the cannulation chamber of FIG. 10 A according to some embodiments.
- FIG. 11 is a schematic illustration of an AVG according to some other embodiments.
- FIGS. 12 and 13 illustrate cross-sectional views of cannulation chambers of the AVG of FIG. 11 according to some embodiments.
- FIGS. 14 and 15 illustrate cross-sectional views of cannulation chambers of the AVG of FIG. 11 according to some other embodiments.
- FIG. 16 is a schematic illustration of an AVG according to some other embodiments.
- FIG. 17 is a schematic illustration of an AVG according to some other embodiments.
- FIG. 18 is a schematic illustration of an AVG according to some other embodiments.
- FIG. 19 is a cross-sectional view- of a cannulation chamber of the AVG of FIG. 18 according to some other embodiments.
- FIG. 20 is a perspective view of an inner layer of the cannulation chamber of FIG. 19 according to some embodiments.
- FIG. 21 is a perspective view of a shell of the cannulation chamber of FIG. 19 according to some embodiments.
- FIG. 22 is a perspective view of an outer layer of the cannulation chamber of FIG. 19 according to some embodiments.
- FIG. 23 is a bottom view of a curved cannulation chamber for use with the AVG of FIG. 18 according to some embodiments.
- the terms “comprising” or “comprises,” “having” or “has,” and “including” or “includes” are open-ended, and includes one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof.
- the term “and/or” includes any and all combinations of one or more of the associated listed items.
- the common abbreviation “e.g.,” which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation “i.e.,” which derives from the Latin phrase “id est,” may be used to specify a particular item from a more general recitation.
- spatially relative terms such as “under,” “below,” “lower,” “over,” “upper,” “downward,” “upward,” “inward, “outward” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
- any one or more aspects or features described with respect to one embodiment may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
- FIGS. 1 - 4 an arteriovenous graft (AVG) 10 according to some embodiments is illustrated in FIGS. 1 - 4 .
- the AVG 10 is configured to be implanted in a subject.
- the AVG 10 includes a first flexible conduit 12 having a first end 14 configured to be connected to an artery 16 of the subject and a second end 18 .
- the AVG 10 also includes a second flexible conduit 22 having a first end 24 configured to be connected to a vein 26 of the subject and a second end 28 .
- blood flows from the first end 14 of the first conduit 12 to the first end 24 of the second conduit 22 .
- the graft 10 could be used as an arterial-arterial graft (for example, vein 26 could instead be an artery).
- a first cannulation chamber 30 has a housing 30 h including an inlet 32 connected to the second end 18 of the first conduit 12 and an outlet 34 .
- the chamber housing 30 h has an open anterior portion including an aperture defining a cannulation port 30 p .
- the cannulation port 30 p is configured to receive a dialysis needle N ( FIGS. 3 and 4 ) therethrough.
- a second cannulation chamber 40 has a housing 40 h including an inlet 42 and an outlet 44 connected to the second end 28 of the second conduit 22 .
- the chamber housing 40 h also has an open anterior portion including an aperture defining a cannulation port 40 p .
- the cannulation port 40 p is configured to receive a dialysis needle N ( FIGS. 3 and 4 ) therethrough.
- a third flexible conduit 52 connects the first chamber 30 and the second chamber 40 .
- the third conduit 52 includes a first end 54 connected to the outlet 34 of the first chamber housing 30 h and a second end 56 connected to the inlet 42 of the second chamber housing 40 h .
- the conduits 12 , 22 , 52 may be formed of an inert biocompatible material such as ePTFE, polyurethane, Dacron, or the like.
- the conduits may also be formed of other biological materials, such as animal or human vessels, or biologically engineered tissue conduit.
- One or more of the conduits 12 , 22 , 52 may be non-kinking or kink-resistant.
- one or more of the conduits may be corrugated and/or include beading material on at least a portion of its outer periphery.
- beading material 58 is included on the outer periphery of the third conduit 52 .
- Such beading material may be in the form of ePTFE wrapped around the outer surface in a spiral or helical configuration, for example.
- the third conduit 52 is non-kinking (or more kink-resistant than one or both of the other conduits 12 , 22 ) to account for possible increased bending at this portion of the graft.
- each chamber housing 30 h , 40 h includes a pair of opposed sidewalls 60 and a posterior wall 70 . As illustrated, the sidewalls 60 extend downwardly from the cannulation port 30 p to the posterior wall 70 .
- the first and second chamber housing 30 h , 40 h are formed of a substantially rigid biocompatible material (e.g., titanium or a substantially rigid polymer or composite) such that, when a dialysis needle is inserted through the cannulation port 30 p , 40 p of a respective chamber, the needle is prevented or substantially prevented from extending through the posterior wall 70 or one of the side walls 60 of the cham ber housing.
- a substantially rigid biocompatible material e.g., titanium or a substantially rigid polymer or composite
- the first and second chamber housings 30 h , 40 h are formed of a semi-rigid biocompatible material (e.g., a puncture-resistant composite) such that, when a dialysis needle is inserted through the cannulation port 30 p , 40 p of a respective chamber, the needle is inhibited from extending through the posterior wall 70 or one of the side walls 60 of the chamber housing.
- the chamber housing material may provide tactile and/or audible feedback to an operator that the dialysis needle has contacted an interior portion of the posterior wall or one of the side walls.
- a self-sealing material may extend across, lie beneath and/or extend over the apertures defining the cannulation ports 30 p , 40 p .
- the self-sealing material 80 extends across the open anterior portion of the housings 30 h , 40 h .
- the self-sealing material 80 is adhered to the housings 30 h , 40 h via a medial-grade adhesive (not shown).
- Enclosed longitudinal passageways 36 , 46 are defined by the housings 30 h , 40 h and the self-sealing material 80 . The longitudinal passageways extend from the inlet to the outlet of the chamber housing.
- the longitudinal passageway 36 extends from the inlet 32 to the outlet 36 of the chamber housing 30 h .
- the longitudinal passageways 36 , 46 define longitudinal fluid flow paths or ports wherein blood may flow therethrough. It will be appreciated from the discussion below that, in other embodiments, conduits may extend through the longitudinal passageways 36 , 46 .
- the chamber housings 30 h , 40 h and/or the self-sealing material 80 may be shaped and configured such that the longitudinal passageways 36 , 46 have a circular or substantially circular cross-section. In those embodiments in which fluid flows through the passageways 36 , 46 , this configuration can minimize disturbance of laminar flow therethrough. Similarly, in those embodiments in which the conduits extend through the passageways 36 , 46 , this configuration can allow the conduits to retain their circular or substantially circular cross-section or shape to inhibit flow disturbances therethrough.
- the self-sealing material 80 is made of a stretchable material that is suitable for repeated punctures.
- the needle N ( FIGS. 3 and 4 ) is inserted through the cannulation ports 30 p , 40 p and the self-sealing material 80 .
- the self-sealing material 80 is then able to self-seal after removal of the needle N.
- the needle N may have a beveled end so as to create more of a "slit-like" puncture in the self-sealing material 80 , which may be easier to "heal" or seal.
- the self-sealing material 80 may have a thickness of between about 1 mm and about 10 mm and between about 1 mm and about 5 mm.
- the cannulation ports 30 p , 40 p may have a length that spans a major portion of the length of the chamber housings 30 h , 40 h . This provides an increased area through which a clinician can make the repeated cannulations needed during hemodialysis (i.e., it permits the clinician to "rotate" the needle puncture site more effectively and with less trauma to the self-sealing ports and the graft in general).
- the chamber housings 30 h , 40 h may have a length L 1 of between about 8 cm and about 20 cm and between about 10 cm and about 15 cm. In some embodiments, the length L 1 of the chamber housings is about 10 cm or about 12 cm.
- the length L 1 may be inclusive of end portions 30 e , 40 e , which are described in more detail below.
- the cannulation ports 30 p , 40 p may have a length L 2 of between about 6 cm and about 18 cm, between about 8 cm and about 13 cm and between about 6 cm and about 10 cm.
- the cannulation ports 30 p , 40 p may have a width transverse to the length L 2 that is chosen to be large enough to facilitate cannulation (i.e., targeting of the needle).
- the ports 30 p , 40 p may also have a width that is chosen such that the ports (or, put another way, the apertures on the anterior face/surface of the chamber housings) do not extend too far along the perimeter of the chamber housings 30 h , 40 h .
- the ports 30 p , 40 p have a width W 1 of between about 6 mm and about 12 mm and about 8 mm and about 10 mm.
- the chamber housings 30 h , 40 h may include a substantially cylindrical center portion 30 c , 40 c and opposed end portions 30 e , 40 e (the chambers 30 , 40 may be thought of as being "torpedo-shaped"). This configuration may aid in tunneling through subcutaneous tissue when the graft is being implanted.
- the end portions 30 e , 40 e may be sized and configured to receive the conduits 12 , 22 , 52 . As illustrated, the end portions 30 e , 40 e have a barbed outer surface (i.e., an outer surface with a plurality of raised outer portions). The ends of the conduits 12 , 22 , 52 may snugly fit over the end portions 30 e , 40 e of the chamber housings.
- the chamber housings 30 h , 40 h have a reduced outer diameter and/or thickness at their end sections 30 e , 40 e .
- the inner diameter of the end portions 30 e , 40 e and the center 30 c , 40 c of the chambers 30 , 40 may be equal or substantially equal so as to minimize flow disturbance therethrough.
- the center portions of the chambers 30 c , 40 c can have an inner diameter between about 6 mm and about 8 mm, an outer diameter of between about 10 mm and about 12 mm, and a wall thickness of between about 1 mm and about 3 mm.
- the end portions of the chambers 30 e , 40 e may have an inner diameter between about 5 mm and about 8 mm, and an outer diameter of between about 6 mm and about 10 mm.
- the flexible conduits 12 , 22 , 52 may have an inner diameter between about 6 mm and about 8 mm and an outer diameter of between about 7 mm and about 9 mm.
- the inner diameter of the end portions 30 e , 40 e and the center portions 30 c , 40 c are equal or substantially equal to promote laminar fluid flow.
- the center portions 30 c , 40 c may have a larger outer diameter than the end portions 30 e , 40 e (for example, the center portions may have an outer diameter of about 10 mm and the end portions may have an outer diameter of about 8 mm to accommodate 8 mm inner diameter conduit or tubing).
- the center portions 30 c , 40 c have a greater material thickness than the end portions 30 e , 40 e . It is noted that the increased relative thickness of the material at the center portion 30 c , 40 c may provide added puncture resistance during cannulation.
- the chamber housings 30 h , 40 h may generally have a stepped configuration with shoulders separating the end portions 30 e , 40 e and the center portion 30 c , 40 c ( FIG. 2 ) or at least a portion of the center portion 30 c , 40 c and/or the end portions 30 e , 40 e may be tapered ( FIG. 3 ).
- connectors may be employed to connect the conduits 12 , 22 , 52 and the inlets/outlets of the chamber housings 30 h , 40 h .
- the end portions 30 e , 40 e may be excluded.
- the chambers housings 30 h , 40 h and/or the conduits 12 , 22 , 52 may include a connector or be sized and configured to fit together (e.g., press-fit).
- the chambers and conduits may be connected in such a way so as to minimize any relative difference in flow area and shape (e.g., maintain a consistent flow path through the graft).
- the graft 10 may have a total (extended) length of between about 30 cm and about 80 cm.
- the conduits 12 , 22 , 52 may each have a length of between about 5 cm and about 15 cm.
- the ends of the conduits 12 , 22 may be trimmed and/or shaped in order to fashion an anastomosis.
- the ends of the conduits 12 , 22 may also have a hooded configuration to present additional options for anastomosis creation.
- the graft is versatile so as to be implanted in different or particular configurations in the body of a subject depending on the implantation location chosen based on suitable vascular anatomy.
- the chambers 30 , 40 (or chamber housings 30 h , 40 h ) may be curved to a varying degree to suit implantation in various locations throughout the body.
- the chamber housings 30 h , 40 h may be formed of a material that has a certain rigidity so as to be puncture-resistant or puncture-proof with respect to a cannulating dialysis needle during a typical hemodialysis procedure.
- This rigidity may not allow for the clinician to adequately bend the chambers during implantation in certain locations of the body (e.g., the upper and lower arm).
- puncture-resistant chambers/housings that are substantially straight or are not curved to the proper degree may not be used in certain applications.
- chambers that are not properly curved for a particular application may result in increased bending or kinking of the conduits 12 , 22 , 52 and which may impart added stress on the conduits and/or produce a more restrictive or tortuous flow path.
- the cannulation chambers may be provided as curved to varying degrees.
- the chamber 30 is shown with the longitudinal passageway 36 extending from the inlet 32 to the outlet 34 .
- a curve angle A1 (also referred to herein as an arc angle A1) is defined by the angle between the passageway 36 at or extending from the inlet 32 and the axis A 3 .
- the axis A 3 is parallel to a longitudinal axis that would be defined by a "straight" chamber.
- a curve angle A2 (also referred to herein as an arc angle A2) is defined by the angle between the passageway 36 at or extending from the outlet 34 and the axis A 3 .
- the chamber 30 may generally be symmetrical; that is, the angles A1 and A2 may be equal.
- a chamber/housing generally referred to as having an "arc angle” or a “curve angle” or being “curved” to a certain value (e.g., number of degrees) is a chamber/housing that has equal or substantially equal angles A1 and A2.
- the chambers may be curved from between about 0 degrees and about 60 degrees. In other words, each of the arc or curve angles A 1 and A 2 may be between about 0 degrees and about 60 degrees.
- the curved chamber creates a curved longitudinal passageway or flow path therethrough. In some embodiments, the chambers are gently and/or evenly curved. As illustrated, the curved chambers may be configured such that surface area of the cannulation port 30 p on the anterior face/surface of the housing retains its advantageously large "target" cannulation area.
- the chambers are curved between about 10 and about 45 degrees, between about 15 and about 45 degrees, between about 10 and about 40 degrees, and between about 10 and about 30 degrees so as to be configured to be im planted in the arm of a subject.
- the two cham bers 30 , 40 may have the same or differing curvature in various embodiments.
- one or both chambers are curved between about 0 and about 45 degrees, between about 5 and about 45 degrees, between about 0 and about 25 degrees, between about 5 and about 20 degrees, between about 10 and 20 degrees, and between about 5 and 15 degrees so as to be configured to be implanted in an upper arm of a subject (e.g., form part of an upper arm loop graft).
- one or both chambers are curved between about 5 and about 60 degrees, between about 10 and about 50 degrees, between about 20 and about 45 degrees, between about 20 and 40 degrees, and between about 25 and 35 degrees so as to be configured to be implanted in a forearm of a subject (e.g., form part of a forearm loop graft) or in a lower extremity of a subject.
- one or both chambers are curved at least about 1, at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, and at least about 10 degrees to facilitate placement in an upper or lower extremity.
- one or both chambers have a visible amount of curvature. It is noted that some larger implantation sites, such as the abdomen and the chest, may requires a lesser amount of or even no chamber curvature.
- FIG. 6 illustrates the AVG 10 implanted in the upper extremity of a subject.
- the chamber 30 may be connected via conduit 12 to the ulnar artery and the chamber 40 may be connected via conduit 22 to the brachial vein, although multiple, various configurations are contemplated.
- the chambers 30 , 40 may be advantageously curved in such implantation sites to accommodate the puncture-proof or puncture resistant chambers and/or to reduce bending or kinking of the conduits.
- at least the conduit 52 may be non-kinking or kink-resistant, as described in more detail above.
- an outer thin veneer layer 150 may surround and extend along the entire length or substantially the entire length of the graft.
- the outer veneer 150 may extend along the entire length of the chambers 30 , 40 and the conduit 52 and at least a portion of the length of the conduits 12 , 22 .
- the veneer 150 may be formed of biocompatible material (e.g., ePTFE) and may aid in tissue incorporation, hemostasis, and device stability as well as to reduce the likelihood of infection.
- the veneer may assist in keeping the self-sealing material 80 (or self-sealing layers 90 , 110 shown in FIGS. 7 and 8 ) in place.
- the chambers 30 , 40 and/or the veneer layer 150 may include indicia 152 at or adjacent the cannulation ports 30 p , 40 p to help ensure that the ports 30 p , 40 p are facing in an upward direction during and after tunneling.
- the indicia 152 may reside on the veneer 150 above and/or adjacent the ports 30 p , 40 p and may read "PORT SIDE UP" or the like.
- the conduits 12 , 22 , 52 and/or the veneer 150 may include indicia to help ensure that the conduits are not twisted during and after tunneling.
- the indicia 152 may comprise one or more lines on the conduits and/or on the veneer 150 that run along the conduits.
- the line(s) may further run above or substantially above the center of the port, or may simply indicate the outline of the cannulation area of the cannulation ports 30 p , 40 p to help ensure that the ports are upward-facing.
- the chamber housings 30 h , 40 h may include ledges 82 that extend in the direction of the longitudinal passageways 36 , 46 ( FIG. 1 ), and the self-sealing material 80 may be at least partially supported by the ledges 82 .
- a member 90 comprising a layer of self-sealing material may surround at least a portion of the outer perimeter of the chamber housings 30 h , 40 h .
- the member 90 may extend along the entire length or along at least a major portion of the length of the chamber housings 30 h , 40 h .
- the members 90 are sized such that self-sealing material covers or extends across the open anterior portion of the chamber housing 30 h , 40 h and the entire length and width of the ports 30 p , 40 p .
- the self sealing material may be positioned relative to the cannulation chamber housing in a variety of ways.
- FIGS. 8 A- 8 C illustrate a cross-section of the chamber 30 .
- a layer of self-sealing material surrounds at least a portion of the outer perimeter of the chamber housing 30 h .
- the layer of self-sealing material may take the form of the member 90 , similar to that shown in FIG. 7 .
- the self-sealing material resides over the cannulation port 30 p .
- the self-sealing material may be as described above with respect to FIG. 8 A , but may also include a relatively thicker portion 92 that extends into the cannulation port 30 p .
- This configuration may allow for a longitudinal passageway or flow path that has a circular or substantially circular cross-section so as to minimize disturbance of lam inar flow therethrough.
- the member 90 need not surround the entire outer perimeter of the cham ber 90 ; for example, the member may extend to intermediate points adjacent the side walls and/or the posterior wall of the chamber housing 30 h (for example, see the points A in FIGS. 8 A- 8 C ).
- the member 90 may resiliently fit around a portion or a major portion of the outer perimeter of the chamber housing 30 h ; this may allow the member 90 to be more easily fitted to and removed from the chamber (e.g., for replacement of member 90 ).
- a layer of self-sealing material may also be formed over the chamber housing 30 h .
- the chamber 30 may be positioned on a template, support fixture, rod, mandrel or the like (shown at 100 and referred to herein as a mandrel).
- a layer of self-sealing material 110 can then be applied.
- the chamber housing 30 h and mandrel 100 may be fitted in a mold and liquid silicone rubber (or other self-sealing material) may be pumped therein or the mold may be immersed in a liquid bath.
- Other manufacturing methods known to those of skill in the art for applying the layer of self-sealing material 110 may also be employed.
- the mandrel 100 may be sized and configured to define the longitudinal passageway 36 ( FIG. 1 ) through the chamber 30 .
- the mandrel can be circular or substantially circular in cross-section so as to define a similarly shaped flow path to minimize disturbance of laminar flow.
- the layer 110 of self-sealing material may include a relatively thicker portion 112 that extends into the cannulation port 30 p .
- a mandrel or the like may be used in connection with the embodiment shown in FIG. 4 . That is, the mandrel may fit beneath the ledges 82 and may be sized and configured to allow a portion 80 ' of the self-sealing material 80 to extend into the cannulation port 30 p . This may allow for the definition of a circular or substantially circular cross-sectional flow path.
- the chambers/chamber housings may have a squared or flat bottom portion.
- the chamber housing 30 h may have a flat or squared bottom portion 30 b adjacent the posterior wall 70 to help prevent the chamber from rolling or twisting as it is being tunneled through tissue.
- the squared or flat bottom portion 30 b may assist in maintaining the cannulation ports 30 p in an upward-facing configuration both during and after tunneling.
- the chambers/chamber housings may also have a domed or generally triangular shape when viewed from the end or cross-section.
- the chambers/chamber housings may also have a domed or generally triangular shape when viewed from the end or cross-section.
- at least a portion of sidewalls 60 of the chamber housing 30 h may extend inwardly from the bottom portions 30 b , 40 b toward the open anterior portion of the chamber housing 30 h adjacent the port 30 p .
- FIGS. 11 - 13 An AVG 200 according to other embodiments is illustrated in FIGS. 11 - 13 .
- the AVG 200 may include any of the features described above in reference to the AVG 10 .
- the primary difference in the embodiment shown in FIGS. 11 - 13 is a reduction in the number of fluid (e.g., blood) contacting components. That is, in the earlier described embodiments, the fluid may contact a plurality of components, including the conduits 12 , 22 , 52 , the chamber housings 30 h , 40 h and/or the self-sealing material 80 associated with the housings 30 h , 40 h .
- one or more conduits may extend through the chambers 30 , 40 to thereby reduce the number of fluid contacting surfaces.
- the AVG 200 includes at least one conduit 202 having first and second end portions 12 ', 22 '.
- the first end portion 12 ' is configured to connect to an artery of a subject at a first end 14 ' and the second end portion is configured to connect to a vein of the subject at a first end 24 '.
- blood flows through the conduit 202 from the first end portion 12 ' to the second end portion 22 '.
- at least a portion of the conduit 202 may be non-kinking or kink-resistant.
- at least a portion of a middle portion 52 ' of the conduit 202 residing between the chambers 30 , 40 may beaded, as described above.
- a pair of cannulation chambers 30 , 40 are positioned between the first and second end portions 12 ', 22 ' of the conduit 202 .
- the chambers 30 , 40 are as described above.
- the chamber 40 includes an elongated housing 40 h having an inlet 42 and an outlet 44 , a pair of side walls 60 , a posterior wall 70 , and an open anterior portion including an aperture defining the cannulation port 40 p .
- Self-sealing material 80 extends across the open anterior portion of the housing 40 h (i.e., across the port 40 p ).
- a longitudinal passageway 46 is defined by the housing 40 h and the self-sealing material 80 .
- the at least one conduit 202 extends through the passageway 46 and therefore defines a longitudinal fluid passageway 46 ' through the at least one conduit 202 .
- the self-sealing material 80 and the conduit 202 may be adhered via a medical-grade adhesive 206 . This configuration may prevent the two components from separating as a needle is inserted therethrough.
- the medical-grade adhesive 206 may also adhere the conduit 202 to the chamber housing 40 h .
- the chamber 30 may have a sim ilar or identical configuration.
- the portion of the AVG 200 including the chamber 30 is shown as including the outer veneer 150 , although it will be understood that the outer veneer 150 will typically extend over at least a portion of the AVG 200 including the chamber 40 .
- FIGS. 14 and 15 Alternative chamber cross-section views are shown in FIGS. 14 and 15 .
- the conduit 202 is shown extending through the chamber housings 30 h , 40 h , it will be appreciated that these chamber designs may be used with the AVG 10 described above.
- the chamber housings 30 h , 40 h shown in FIGS. 14 and 15 are elongated along a center or a bottom portion of the housing, and may thereby assist in maintaining the cannulation ports in an upward-facing configuration both during and after tunneling in much the same way as the configurations illustrated in FIGS. 9 and 10 .
- FIG. 16 An AVG 300 according to other embodiments is illustrated in FIG. 16 .
- the primary difference in this embodiment is that the AVG 300 includes only one cannulation chamber 30 '.
- the AVG 300 may include a conduit 202 extending through the housing of the chamber 30 ' in much the same way as described above in connection with the AVG 200 .
- the AVG 300 may include first and second conduits 12 , 22 in much the same way as described above in connection with the AVG 10 . That is, the first conduit 12 connects an artery and the chamber inlet 32 and the second conduit 22 connects the chamber outlet 34 and a vein.
- the chamber 30 ' may have a length greater than above-described lengths for the chambers 30 , 40 so as to provide an increased surface area for the cannulation port 30 ' p .
- the length L 3 may be between about 10 cm and about 20 cm and between about 10 cm and about 15 cm.
- the chamber 30 ' may have increased curvature due to the lack of a second curved chamber and/or a middle conduit portion.
- the chamber 30 ' may have an arc or a curve angle (see FIG. 5 ) of between about 5 and about 90 degrees, between about 15 and about 90 degrees, between about 30 and about 80 degrees, and greater than about 40 degrees to accommodate placement in, for example, an upper arm of a subject.
- the conduits 12 , 14 may have a length L 4 of between about 10 cm and about 20 cm and may also be trimmed to suit a particular application. At a portion of at least one of the conduits 12 , 14 (or equivalent portions of the conduit 202 ) may be kink-proof or kink-resistant. As illustrated, beading material 58 is wrapped around a length L 5 of the conduit 22 adjacent the chamber 30 '.
- FIG. 17 An AVG 400 according to other embodiments is shown in FIG. 17 .
- the AVG 400 includes three or more cannulation chambers 30 ".
- the AVG 400 includes 11 chambers 30 "; however, it will be appreciated that fewer or more chambers may be employed.
- Each chamber 30 " may include all the features described above in connection with the chambers 30 , 40 and 30 '. That is, each chamber 30 " includes a housing 30 "h having an inlet, an outlet and an open anterior portion defining a cannulation port 30 "p with self-sealing material extending across or adjacent the cannulation port.
- each chamber 30 " has a longitudinal passageway therethrough as described above.
- Each chamber 30 " will generally have a shorter length L 6 than as described above in the other embodiments.
- the length L 6 may be between about 1 cm and about 7 cm, between about 1 cm and about 5 cm, and about 3 cm in various embodiments.
- the AVG 400 may include a conduit 202 extending through the longitudinal passageway each chamber 30 " in much the same way as described above in connection with the AVG 200 .
- the chambers 30 " will generally be spaced closer together than in the embodiments described above.
- the length L 7 of the spacing may be between about 0.25 cm and about 5 cm, between about 0.25 cm and about 2 cm, and between about 0.5 cm and about 1 cm in various embodiments.
- the AVG 400 may provide flexibility when being implanted in a subject. That is, the AVG 400 may be bent or otherwise manipulated to accommodate a particular implantation site. Also, the plurality of chambers have a generally large overall surface area of self-sealing material, thereby retaining the advantages described above.
- FIG. 18 An AVG 500 according to other embodiments is illustrated in FIG. 18 .
- the AVG 500 may include features described above in reference to the AVGs 10 , 200 and 300 .
- the AVG 500 may have a reduced number of fluid (e.g., blood) contacting components.
- the chambers of the AVG 500 are constructed somewhat differently than the chambers of the AVGs 10 , 200 and 300 , as will be described below.
- the AVG 500 includes a conduit 202 having first and second end portions 12 ', 22 '.
- the conduit 202 may be formed of an inert biocompatible material such as ePTFE, polyurethane, Dacron, or the like.
- the first end portion 12 ' is configured to connect to an artery of a subject at an end 14 ' thereof, like the end 14 shown in FIG. 1 .
- the second end portion 22 ' is configured to connect to a vein of the subject at an end 24 ' thereof, much like the end 24 shown in FIG. 1 .
- blood flows through the conduit 202 from the first end portion 12 ' to the second end portion 22 '.
- a pair of cannulation chambers 30 '", 40 '" are positioned in a spaced-apart relationship between the first and second end portions 12 ', 22 ' of the conduit 202 .
- the chambers 30 '", 40 '" may be identical or substantially identical.
- the chamber 30 '" includes an inlet 32 and an outlet 34 .
- the chamber 40 '" includes an inlet 42 and an outlet 44 .
- the conduit 202 extends through the chamber 30 '" from the inlet 32 to the outlet 34 .
- the conduit 202 extends through the chamber 40 '" from the inlet 42 to the outlet 44 .
- a middle portion 52 ' of the conduit 202 is disposed between the chambers 30 '", 40 '".
- Each of the chambers 30 '", 40 '" includes an elongated chamber body 210 that surrounds the conduit 202 .
- the chamber bodies 210 define the respective chamber inlets 32 , 42 and the chamber outlets 34 , 44 .
- Each of the chambers 30 '", 40 '" also includes an elongated shell or shield 208 .
- the shell 208 may be embedded in the chamber body 210 .
- FIG. 19 A cross sectional view of the chamber 30 "' is shown in FIG. 19 .
- the chamber body 210 includes an inner layer 212 and an outer layer 214 .
- the inner layer 212 may be annular and define a chamber passageway 213 .
- the chamber passageway 213 may have a longitudinal axis A 4 that corresponds to a longitudinal axis A 5 of the conduit 202 (e.g., a fluid flow passageway or path of the conduit 202 ).
- the shell 208 may be disposed between the inner layer 212 and the outer layer 214 .
- the inner layer 212 may fit over the conduit 202 .
- the inner layer 212 may be molded around the conduit 202 .
- the inner layer 212 may be adhered or otherwise attached to the conduit 202 .
- the inner layer 212 is formed of a self-sealing material (e.g., but not limited to, silicone).
- the inner layer 212 may be received in a cavity 209 of the shell 208 .
- the shell 208 may be molded to the inner layer 212 .
- the shell 208 may be adhered or otherwise attached to the inner layer 212 .
- the shell 208 may generally have the shape of an open-ended semi-cylinder and therefore surround about 180 degrees of the outer circumference of the inner layer 212 .
- the shell 208 may be C-shaped or U-shaped.
- the shell 208 includes a posterior wall 70 ' and opposing sidewalls 60 ' defining the cavity 209 .
- the shell 208 has a length that is at least a major portion of the length of the inner layer 212 . In some embodiments, the length of the shell 208 and the inner layer 212 are substantially the same.
- the shell 208 is formed of a substantially rigid biocompatible material (e.g., titanium or a substantially rigid polymer or composite).
- the shell 208 and the inner layer 212 may be received in the outer layer 214 .
- the outer layer 214 may be molded around the inner layer 212 and/or the shell 208 .
- the inner layer 212 and/or the shell 208 may be adhered or otherwise attached to the outer layer 214 .
- the outer layer 214 may be formed of any suitable material; for example, a material that facilitates bonding or molding with the inner layer 212 .
- the outer layer may be formed of a self-sealing material (e.g., but not limited to, silicone).
- the outer layer 214 includes a cannulation port 216 .
- the cannulation port 216 exposes the self-sealing material of the inner layer 212 .
- the outer layer 214 can include an additional layer of self-sealing material across the cannulation port 216 .
- the chamber body 210 may include cannulation port locating features.
- the cannulation port 216 may include a raised perimeter or perimeter portion 218 such that the cannulation port can be tactilely and/or visually identified when the AVG 500 is implanted in a subject. That is, the raised perimeter 218 may be visible through the skin of the subject and/or felt through the skin by medical personnel.
- the needle when a dialysis needle is inserted through the cannulation port 216 and the self-sealing material (e.g., the inner layer 212 ), the needle may be inhibited or prevented from extending through the shell 208 (e.g., the posterior or the side walls of the shell 208 ).
- the self-sealing material e.g., the inner layer 212
- the shell 208 , the inner layer 212 and the outer layer 214 of the chamber housing 210 may be provided as an integrated chamber 30 '" rather than assembled as described above.
- the chamber 30 '" may then be fit onto a graft conduit, such as the conduit 202 .
- the conduit 202 may be received in the chamber passageway 213 (e.g., pulled through the chamber passageway 213 ).
- the chamber 30 "' may also be molded to the conduit 202 or otherwise attached (e.g., adhered) to the conduit 202 .
- beading material 58 may be included on the outer periphery of the middle portion 52 ' of the conduit 202 . Also, as illustrated, beading material 58 may be wrapped around a length L 6 of the conduit 202 adjacent the chamber 30 "' and/or the chamber 40 '". In some embodiments, the length L 6 is about 1 to 2 cm.
- the outer veneer 150 may be provided over at least a portion of the AVG 500 .
- the outer veneer 150 will typically extend over at least a major portion of the AVG 500 including the chambers 30 '" and 40 '" and the middle portion 52 ' of the conduit 202 .
- the outer veneer 150 may also extend from the chambers 30 '", 40 '" toward or to the first and second end portion 12 ', 24 ' of the conduit 202 .
- the chambers 30 '", 40 '" may include a flattened bottom portion or surface 220 . As described above, such a configuration may inhibit malpositioning and/or twisting of the graft.
- the chambers/chamber bodies may have a domed or generally triangular shape when viewed from the end or cross-section. In some other embodiments, the chambers/chamber bodies may have a substantially circular cross-section, an elliptical cross-section or a generally oval cross-section.
- the chambers 30 '", 40 '" may be curved to have are angles A1, A2 in the same manner as described above in connection with the chamber 30 .
- the arc angles A1 and A2 may be equal for a particular chamber 30 '".
- the values of the arc angles A1, A2 may be as described above in connection with the chamber 30 .
- the angles A1 and A2 may be between about 10 and 30 degrees to facilitate placement in an upper extremity of a patient.
- the chambers 30 '" and 40 '" each have a center portion or section and opposed end portions or sections (e.g., the center portion 30 c and the end portions 30 e shown in FIG. 23 ).
- the chambers 30 '" and 40 '" may have the same dimensions as the dimensions of the chambers 30 , 40 described above.
- the cannulation ports 216 may have the same dimensions as the dimensions of the cannulation ports 30 p, 40 p described above.
- the conduit 202 including the first end portion 12 ', the second end portion 22 ' and the middle portion 52 ', may have the same dimensions and properties as the conduits 12 , 22 and 52 described above.
- the chambers described herein may be supplied separately from their associate conduit(s).
- the chamber 30 '" and/or the chamber 40 '" may be provided to a clinician, who may then fit the chambers 30 '" and/or 40 '" to an off-the shelf graft conduit as needed for a particular application.
- the chambers 30 '" and/or 40 "' may be supplied with the conduit 202 for later assembly and use.
Abstract
An arteriovenous dialysis access graft configured to be implanted in a subject includes: at least one flexible conduit having first and second end portions, wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion; and at least one cannulation chamber positioned between the first end portion and the second end portion of the at least one conduit. The chamber includes: an elongated housing having an inlet at a first end thereof and an outlet at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port; a self-sealing material extending across the cannulation port; and a longitudinal passageway defined by the housing and the self-sealing material that extends from the inlet to the outlet of the housing. The housing of the at least one chamber is formed of a substantially rigid material such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port, the needle is inhibited or prevented from extending through the posterior or the side walls of the housing.
Description
- This application is a continuation of U.S.
Application 16/580,423, filed Sep. 24, 2019, which is a continuation of U.S. Application 15/450,523, filed Mar. 6, 2017, now U.S. Pat. 10,420,874, issued Sep. 24, 2019, which is a continuation of U.S.Application 14/027,986, filed Sep. 16, 2013, now U.S. Pat. 9,585,998, issued Feb. 15, 2017, which is a continuation-in-part of International Application PCT/US2012/029449, filed Mar. 16, 2012, which claims priority to U.S. Provisional Pat. Application No. 61/453,211, filed Mar. 16, 2011, the disclosure of which are incorporated by reference herein in their entireties. - This invention relates to grafts and, more particularly, to arteriovenous grafts for dialysis.
- Dialysis treatment of individuals suffering from renal failure requires that blood be withdrawn and cycled through a dialysis machine that performs the function of the failed kidneys. This process, termed hemodialysis, must be repeated at a regular interval (e.g., three times per week) and thus requires repeated punctures using dialysis needles. Relatively large gauge needles are required to promote the high flow rates required during dialysis. Frequent puncturing of autogenous arteriovenous access as well as prosthetic arteriovenous access with large bore needles can cause trauma, conduit degeneration, hematoma formation, pseudoaneurysm formation, loss of patency, or even hemorrhage and exsanguination.
- A common technique to provide vascular access for hemodialysis, therefore, is to connect a prosthetic graft or shunt between an artery and a vein in, for example, the upper or lower extremity. Occasionally, patient complexity may also warrant access placement on the chest or abdominal wall. Conventional arteriovenous grafts (AVGs) are often constructed of a polymeric material such as expanded polytetrafluoroethylene (ePTFE) or polyetherurethaneurea.
- A significant mode of failure of AVGs is related to a traumatic cannulation with the dialysis needle. This may occur as the needle traverses the anterior wall of the AVG and then continues through the posterior wall (or a sidewall) of the graft. This type of trauma causes a defect in the posterior and/or side wall of the graft and often results in hematoma formation which can ultimately lead to graft thrombosis (i.e., the formation of a blood clot inside the graft, obstructing the flow of blood therethrough) by external compression of the graft and ultimate graft failure.
- Moreover, repeated punctures of the graft material (such as ePTFE) promotes coring and degeneration of the graft material which often leads to rupture of the graft, pseudoaneurysm formation, and graft thrombosis. Also, ePTFE grafts are generally not self-sealing when punctured and usually require implantation three, four or more weeks prior to puncture to allow for graft incorporation (a layer of fibrotic tissue that attaches to the outside surface of the graft). The layer of fibrotic tissue may prevent leakage of blood through the wall of the graft upon withdrawal of the dialysis needles and if cannulated before this time could lead to hematoma formation between the graft and surrounding tissue. This hematoma could cause adverse events such as graft occlusion, lack of incorporation of the graft and increased chance for infection. However, there is often very little subcutaneous tissue between the surface of the skin and the anterior face of the graft, and the above-mentioned problems may occur even after waiting for tissue incorporation.
- U.S. Pat. No. 6,146,414 to Gelman, the disclosure of which is incorporated herein in its entirety, describes tube grafts having expanded regions and shields at posterior portions of the expanded regions. The shields have added rigidity relative to the tube to thereby signal to the operator when the needle tip hits a shield during cannulation. The shields are either incorporated into the tube graft or are added as a separate component during assembly, thereby adding complexity to the manufacturing process. The Gelman patent describes that the shields may be rigid or semi-rigid but only describes straight grafts (i.e., grafts without curvature). Substantially rigid shields would require that the grafts described in the Gelman patent be kept in a generally straight configuration, and such a configuration may be difficult or impossible to use at many AVG implantation sites, such as forearms and upper arms. Semi-rigid shields may allow for some bending of the graft to accommodate placement in these areas, but would reduce or eliminate the capability of the shield to prevent needle penetration through the shield or warn the operator of impending penetration. Also, bending of grafts employing semi-rigid shields could weaken the graft and/or disrupt flow characteristics for blood flowing therethrough. Finally, the Gelman patent does not recognize the need for a self-sealing graft or a portion thereof.
- Self-sealing vascular access grafts have been described in, for example, U.S. Pat. Nos. 5,192,310 to Herweck et al., 7,452,374 to Hain et al., and 7,780,622 to Fitzpatrick et al., the disclosures of which are incorporated herein in their entireties. However, none of these patents consider the problem of dialysis needles puncturing side walls or anterior walls during cannulation. U.S. Pat. No. 6,261,257 to Uflacker et al., the disclosure of which is incorporated herein in its entirety, describes grafts with straight port chambers including self-sealing septums. The problem of puncturing side walls or anterior walls during cannulation is also not contemplated in the Uflacker patent. Even if the straight chambers were constructed of a rigid material to ostensibly provide puncture resistance, such a configuration would not be suitable for implantation in the upper or lower extremities, as described above.
- Thus, there is a need for arteriovenous grafts configured to be implanted in a subject (e.g., in an upper or lower extremity of a subject) with puncture resistant posterior walls and side walls. There is also a need for such arteriovenous grafts to include self-sealing ports at the anterior surfaces of the graft. Such designs may help prevent traumatic cannulations and/or graft degeneration so as to lead to higher patency rates for arteriovenous grafts, decrease the risk of hemorrhage or infection for hemodialysis patients, and reduce overall vascular access related healthcare costs.
- Embodiments of the invention are directed to an arteriovenous dialysis access graft configured to be implanted in a subject. The arteriovenous graft (AVG) includes at least one flexible conduit having first and second end portions, wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion. The AVG includes at least one cannulation chamber positioned between the first end portion and the second end portion of the at least one conduit. The at least one chamber includes: an elongated housing having an inlet at a first end thereof and an outlet at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port; a self-sealing material extending across the cannulation port; and a longitudinal passageway defined by the housing and the self-sealing material that extends from the inlet to the outlet of the housing. The housing of the at least one chamber is formed of a substantially rigid material such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port, the needle is inhibited or prevented from extending through the posterior or the side walls of the housing.
- According to some embodiments, the at least one chamber comprises a plurality of chambers. According to some embodiments, the at least one conduit extends through the longitudinal passageway of the chamber(s).
- According to other embodiments, the at least one conduit comprises first and second flexible conduits. Each conduit has a first and second end. The first end of the first conduit is configured to connect to the artery of the subject and the second end of the first conduit is connected to the inlet of the chamber; the first end of the second conduit is configured to connect to the vein of the subject and the second end of the second conduit is connected to the outlet of the of the chamber.
- According to some embodiments, the at least one cannulation chamber comprises first and second cannulation chambers and the at least one conduit comprises first, second and third flexible conduits, with each conduit having a first and second end. The first end of the first conduit is configured to connect to the artery of the subject and the second end of the first conduit is connected to the inlet of the first chamber; the first end of the second conduit is configured to connect to the vein of the subject and the second end of the second conduit is connected to the outlet of the of the second chamber; and the first end of the third conduit is connected to the outlet of the first chamber and the second end of the third conduit is connected to the inlet of the second chamber.
- According to some embodiments, at least one of the first and second chambers is curved such that the longitudinal passageway has an arc angle. The arc angle may be between about 5 and about 45 degrees to accommodate placement in an upper arm of the subject. The arc angle may be between about 5 degrees and about 60 degrees to accommodate placement in a forearm or lower extremity of the subject.
- The self-sealing material may be formed of a stretchable material such as silicone or polyurethane. The conduit(s) may be formed of a biocompatible polymeric material such as ePTFE. The chamber housing(s) may be formed of a biocompatible material such as titanium or a rigid polymer. Each chamber housing material may provide tactile and/or audible feedback to an operator that the dialysis needle has contacted an interior portion of the posterior wall or one of the side walls.
-
FIG. 1 is a schematic illustration of an arteriovenous graft (AVG) according to some embodiments. -
FIG. 2 is an exploded view of the AVG ofFIG. 1 according to some embodiments. -
FIG. 3 is a side view of a cannulation chamber of the AVG ofFIG. 1 according to some embodiments. -
FIG. 4 is a cross-section view of a cannulation chamber of the AVG ofFIG. 1 according to some embodiments. -
FIG. 5 is a top view of a curved cannulation chamber for use with the AVG ofFIG. 1 according to some embodiments. -
FIG. 6 is a schematic illustration of the AVG ofFIG. 1 implanted in an upper extremity (forearm) of a subject according to some embodiments. -
FIG. 7 is a top view of the AVG ofFIG. 1 with a member comprising self-sealing material extending across the each of the cannulation chambers according to some embodiments. -
FIGS. 8A-8C illustrate cross-section views of one of the cannulation chambers ofFIG. 7 according to various embodiments. -
FIG. 9A is bottom view of a cannulation chamber for use with the AVG ofFIG. 1 according to some embodiments. -
FIG. 9B is a cross-sectional view of the cannulation chamber ofFIG. 9A according to some embodiments. -
FIG. 10A is an end view of a cannulation chamber for use with the AVG ofFIG. 1 according to some embodiments. -
FIG. 10B is a cross-sectional view of the cannulation chamber ofFIG. 10A according to some embodiments. -
FIG. 11 is a schematic illustration of an AVG according to some other embodiments. -
FIGS. 12 and 13 illustrate cross-sectional views of cannulation chambers of the AVG ofFIG. 11 according to some embodiments. -
FIGS. 14 and 15 illustrate cross-sectional views of cannulation chambers of the AVG ofFIG. 11 according to some other embodiments. -
FIG. 16 is a schematic illustration of an AVG according to some other embodiments. -
FIG. 17 is a schematic illustration of an AVG according to some other embodiments. -
FIG. 18 is a schematic illustration of an AVG according to some other embodiments. -
FIG. 19 is a cross-sectional view- of a cannulation chamber of the AVG ofFIG. 18 according to some other embodiments. -
FIG. 20 is a perspective view of an inner layer of the cannulation chamber ofFIG. 19 according to some embodiments. -
FIG. 21 is a perspective view of a shell of the cannulation chamber ofFIG. 19 according to some embodiments. -
FIG. 22 is a perspective view of an outer layer of the cannulation chamber ofFIG. 19 according to some embodiments. -
FIG. 23 is a bottom view of a curved cannulation chamber for use with the AVG ofFIG. 18 according to some embodiments. - The present invention now will be described more fully with reference to the accompanying drawings, in which embodiments of the invention are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.
- As used herein, the terms "comprising" or "comprises," "having" or "has," and "including" or "includes" are open-ended, and includes one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
- As used herein, the common abbreviation "e.g.," which derives from the Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation "i.e.," which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation.
- The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
- Well-known functions or constructions may not be described in detail for brevity and/or clarity.
- Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
- In addition, spatially relative terms, such as "under," "below," "lower," "over," "upper," "downward," "upward," "inward, "outward" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
- It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present.
- It is noted that any one or more aspects or features described with respect to one embodiment may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below.
- Turning now to the figures, an arteriovenous graft (AVG) 10 according to some embodiments is illustrated in
FIGS. 1-4 . TheAVG 10 is configured to be implanted in a subject. TheAVG 10 includes a firstflexible conduit 12 having afirst end 14 configured to be connected to anartery 16 of the subject and a second end 18. TheAVG 10 also includes a secondflexible conduit 22 having afirst end 24 configured to be connected to avein 26 of the subject and a second end 28. In this regard, blood flows from thefirst end 14 of thefirst conduit 12 to thefirst end 24 of thesecond conduit 22. It is noted that thegraft 10 could be used as an arterial-arterial graft (for example,vein 26 could instead be an artery). - A
first cannulation chamber 30 has ahousing 30 h including aninlet 32 connected to the second end 18 of thefirst conduit 12 and anoutlet 34. Thechamber housing 30 h has an open anterior portion including an aperture defining acannulation port 30 p. Thecannulation port 30 p is configured to receive a dialysis needle N (FIGS. 3 and 4 ) therethrough. - Similarly, a
second cannulation chamber 40 has ahousing 40 h including aninlet 42 and anoutlet 44 connected to the second end 28 of thesecond conduit 22. Thechamber housing 40 h also has an open anterior portion including an aperture defining acannulation port 40 p. Thecannulation port 40 p is configured to receive a dialysis needle N (FIGS. 3 and 4 ) therethrough. - A third
flexible conduit 52 connects thefirst chamber 30 and thesecond chamber 40. As illustrated, thethird conduit 52 includes a first end 54 connected to theoutlet 34 of thefirst chamber housing 30 h and a second end 56 connected to theinlet 42 of thesecond chamber housing 40 h. - The
conduits - One or more of the
conduits FIG. 1 ,beading material 58 is included on the outer periphery of thethird conduit 52. Such beading material may be in the form of ePTFE wrapped around the outer surface in a spiral or helical configuration, for example. In some embodiments, thethird conduit 52 is non-kinking (or more kink-resistant than one or both of theother conduits 12, 22) to account for possible increased bending at this portion of the graft. - Referring to
FIGS. 3 and 4 , eachchamber housing opposed sidewalls 60 and aposterior wall 70. As illustrated, thesidewalls 60 extend downwardly from thecannulation port 30 p to theposterior wall 70. - In some embodiments, the first and
second chamber housing cannulation port posterior wall 70 or one of theside walls 60 of the cham ber housing. In some other em bodim ents, the first andsecond chamber housings cannulation port posterior wall 70 or one of theside walls 60 of the chamber housing. In either case, the chamber housing material may provide tactile and/or audible feedback to an operator that the dialysis needle has contacted an interior portion of the posterior wall or one of the side walls. - A self-sealing material (e.g., but not limited to, silicone) may extend across, lie beneath and/or extend over the apertures defining the
cannulation ports FIG. 2 , the self-sealingmaterial 80 extends across the open anterior portion of thehousings material 80 is adhered to thehousings longitudinal passageways 36, 46 (FIG. 1 ) are defined by thehousings material 80. The longitudinal passageways extend from the inlet to the outlet of the chamber housing. For example, referring to thechamber 30, thelongitudinal passageway 36 extends from theinlet 32 to theoutlet 36 of thechamber housing 30 h. In the illustrated embodiment, thelongitudinal passageways longitudinal passageways - The chamber housings 30 h, 40 h and/or the self-sealing
material 80 may be shaped and configured such that thelongitudinal passageways passageways passageways - The self-sealing
material 80 is made of a stretchable material that is suitable for repeated punctures. The needle N (FIGS. 3 and 4 ) is inserted through thecannulation ports material 80. The self-sealingmaterial 80 is then able to self-seal after removal of the needle N. The needle N may have a beveled end so as to create more of a "slit-like" puncture in the self-sealingmaterial 80, which may be easier to "heal" or seal. In various embodiments the self-sealingmaterial 80 may have a thickness of between about 1 mm and about 10 mm and between about 1 mm and about 5 mm. - The
cannulation ports chamber housings FIG. 3 , in various embodiments, thechamber housings end portions cannulation ports - Furthermore, the
cannulation ports ports chamber housings FIG. 2 , in various embodiments, theports - As shown in
FIGS. 2 and 3 , thechamber housings cylindrical center portion opposed end portions chambers end portions conduits end portions conduits end portions - Still referring to
FIGS. 2 and 3 , thechamber housings end sections end portions center chambers - In some embodiments, the center portions of the
chambers chambers flexible conduits - In some embodiments, the inner diameter of the
end portions center portions center portions end portions center portions end portions center portion - The chamber housings 30 h, 40 h may generally have a stepped configuration with shoulders separating the
end portions center portion FIG. 2 ) or at least a portion of thecenter portion end portions FIG. 3 ). - It is noted that connectors may be employed to connect the
conduits chamber housings end portions conduits - In some embodiments, the
graft 10 may have a total (extended) length of between about 30 cm and about 80 cm. Theconduits conduits conduits - In some embodiments, the graft is versatile so as to be implanted in different or particular configurations in the body of a subject depending on the implantation location chosen based on suitable vascular anatomy. In this regard, the
chambers 30, 40 (orchamber housings chamber housings conduits - Thus, referring to
FIG. 5 , the cannulation chambers may be provided as curved to varying degrees. Thechamber 30 is shown with thelongitudinal passageway 36 extending from theinlet 32 to theoutlet 34. A curve angle A1 (also referred to herein as an arc angle A1) is defined by the angle between thepassageway 36 at or extending from theinlet 32 and the axis A3. The axis A3 is parallel to a longitudinal axis that would be defined by a "straight" chamber. Similarly, a curve angle A2 (also referred to herein as an arc angle A2) is defined by the angle between thepassageway 36 at or extending from theoutlet 34 and the axis A3. Thechamber 30 may generally be symmetrical; that is, the angles A1 and A2 may be equal. For the purposes of the present application, a chamber/housing generally referred to as having an "arc angle" or a "curve angle" or being "curved" to a certain value (e.g., number of degrees) is a chamber/housing that has equal or substantially equal angles A1 and A2. - The chambers may be curved from between about 0 degrees and about 60 degrees. In other words, each of the arc or curve angles A1 and A2 may be between about 0 degrees and about 60 degrees. The curved chamber creates a curved longitudinal passageway or flow path therethrough. In some embodiments, the chambers are gently and/or evenly curved. As illustrated, the curved chambers may be configured such that surface area of the
cannulation port 30 p on the anterior face/surface of the housing retains its advantageously large "target" cannulation area. - In various embodiments, the chambers are curved between about 10 and about 45 degrees, between about 15 and about 45 degrees, between about 10 and about 40 degrees, and between about 10 and about 30 degrees so as to be configured to be im planted in the arm of a subject. The two
cham bers - In some embodiments, one or both chambers are curved between about 0 and about 45 degrees, between about 5 and about 45 degrees, between about 0 and about 25 degrees, between about 5 and about 20 degrees, between about 10 and 20 degrees, and between about 5 and 15 degrees so as to be configured to be implanted in an upper arm of a subject (e.g., form part of an upper arm loop graft). In various embodiments, one or both chambers are curved between about 5 and about 60 degrees, between about 10 and about 50 degrees, between about 20 and about 45 degrees, between about 20 and 40 degrees, and between about 25 and 35 degrees so as to be configured to be implanted in a forearm of a subject (e.g., form part of a forearm loop graft) or in a lower extremity of a subject.
- In various embodiments, one or both chambers are curved at least about 1, at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, and at least about 10 degrees to facilitate placement in an upper or lower extremity. In some embodiments, one or both chambers have a visible amount of curvature. It is noted that some larger implantation sites, such as the abdomen and the chest, may requires a lesser amount of or even no chamber curvature.
-
FIG. 6 illustrates theAVG 10 implanted in the upper extremity of a subject. For example, in the illustrated embodiment, thechamber 30 may be connected viaconduit 12 to the ulnar artery and thechamber 40 may be connected viaconduit 22 to the brachial vein, although multiple, various configurations are contemplated. It can be seen that thechambers conduit 52 may be non-kinking or kink-resistant, as described in more detail above. - Referring back to
FIG. 4 , an outerthin veneer layer 150 may surround and extend along the entire length or substantially the entire length of the graft. In some embodiments, theouter veneer 150 may extend along the entire length of thechambers conduit 52 and at least a portion of the length of theconduits veneer 150 may be formed of biocompatible material (e.g., ePTFE) and may aid in tissue incorporation, hemostasis, and device stability as well as to reduce the likelihood of infection. The veneer may assist in keeping the self-sealing material 80 (or self-sealinglayers FIGS. 7 and 8 ) in place. - As illustrated in
FIG. 11 , thechambers veneer layer 150 may includeindicia 152 at or adjacent thecannulation ports ports indicia 152 may reside on theveneer 150 above and/or adjacent theports conduits veneer 150 may include indicia to help ensure that the conduits are not twisted during and after tunneling. For example, theindicia 152 may comprise one or more lines on the conduits and/or on theveneer 150 that run along the conduits. The line(s) may further run above or substantially above the center of the port, or may simply indicate the outline of the cannulation area of thecannulation ports - Returning to
FIG. 4 , thechamber housings ledges 82 that extend in the direction of thelongitudinal passageways 36, 46 (FIG. 1 ), and the self-sealingmaterial 80 may be at least partially supported by theledges 82. - In other embodiments, and as illustrated in
FIG. 7 , amember 90 comprising a layer of self-sealing material may surround at least a portion of the outer perimeter of thechamber housings member 90 may extend along the entire length or along at least a major portion of the length of thechamber housings members 90 are sized such that self-sealing material covers or extends across the open anterior portion of thechamber housing ports - As exemplified in
FIGS. 8A-8C , the self sealing material may be positioned relative to the cannulation chamber housing in a variety of ways.FIGS. 8A-8C illustrate a cross-section of thechamber 30. InFIG. 8A , a layer of self-sealing material surrounds at least a portion of the outer perimeter of thechamber housing 30 h. The layer of self-sealing material may take the form of themember 90, similar to that shown inFIG. 7 . In this regard, the self-sealing material resides over thecannulation port 30 p. - Referring to
FIG. 8B , the self-sealing material may be as described above with respect toFIG. 8A , but may also include a relativelythicker portion 92 that extends into thecannulation port 30 p. This configuration may allow for a longitudinal passageway or flow path that has a circular or substantially circular cross-section so as to minimize disturbance of lam inar flow therethrough. - In some embodiments, the
member 90 need not surround the entire outer perimeter of thecham ber 90; for example, the member may extend to intermediate points adjacent the side walls and/or the posterior wall of thechamber housing 30 h (for example, see the points A inFIGS. 8A-8C ). In this regard, themember 90 may resiliently fit around a portion or a major portion of the outer perimeter of thechamber housing 30 h; this may allow themember 90 to be more easily fitted to and removed from the chamber (e.g., for replacement of member 90). - A layer of self-sealing material may also be formed over the
chamber housing 30 h. Referring toFIG. 8C , thechamber 30 may be positioned on a template, support fixture, rod, mandrel or the like (shown at 100 and referred to herein as a mandrel). A layer of self-sealingmaterial 110 can then be applied. For example, thechamber housing 30 h andmandrel 100 may be fitted in a mold and liquid silicone rubber (or other self-sealing material) may be pumped therein or the mold may be immersed in a liquid bath. Other manufacturing methods known to those of skill in the art for applying the layer of self-sealingmaterial 110 may also be employed. - The
mandrel 100 may be sized and configured to define the longitudinal passageway 36 (FIG. 1 ) through thechamber 30. In some embodiments, the mandrel can be circular or substantially circular in cross-section so as to define a similarly shaped flow path to minimize disturbance of laminar flow. Thus, thelayer 110 of self-sealing material may include a relativelythicker portion 112 that extends into thecannulation port 30 p. - It is noted that a mandrel or the like may be used in connection with the embodiment shown in
FIG. 4 . That is, the mandrel may fit beneath theledges 82 and may be sized and configured to allow a portion 80' of the self-sealingmaterial 80 to extend into thecannulation port 30 p. This may allow for the definition of a circular or substantially circular cross-sectional flow path. - In some embodiments, the chambers/chamber housings may have a squared or flat bottom portion. For example, as illustrated in
FIGS. 9A and 9B , thechamber housing 30 h may have a flat or squaredbottom portion 30 b adjacent theposterior wall 70 to help prevent the chamber from rolling or twisting as it is being tunneled through tissue. In this regard, the squared orflat bottom portion 30 b may assist in maintaining thecannulation ports 30 p in an upward-facing configuration both during and after tunneling. - In other embodiments, the chambers/chamber housings may also have a domed or generally triangular shape when viewed from the end or cross-section. For example, as illustrated in
FIGS. 10A and 10B , at least a portion ofsidewalls 60 of thechamber housing 30 h may extend inwardly from thebottom portions 30 b, 40 b toward the open anterior portion of thechamber housing 30 h adjacent theport 30 p. - An
AVG 200 according to other embodiments is illustrated inFIGS. 11-13 . TheAVG 200 may include any of the features described above in reference to theAVG 10. The primary difference in the embodiment shown inFIGS. 11-13 is a reduction in the number of fluid (e.g., blood) contacting components. That is, in the earlier described embodiments, the fluid may contact a plurality of components, including theconduits chamber housings material 80 associated with thehousings FIGS. 10-12 , one or more conduits may extend through thechambers - The
AVG 200 includes at least oneconduit 202 having first and second end portions 12', 22'. The first end portion 12' is configured to connect to an artery of a subject at a first end 14' and the second end portion is configured to connect to a vein of the subject at a first end 24'. In this regard, blood flows through theconduit 202 from the first end portion 12' to the second end portion 22'. Although not shown, at least a portion of theconduit 202 may be non-kinking or kink-resistant. For example, at least a portion of a middle portion 52' of theconduit 202 residing between thechambers - As illustrated, a pair of
cannulation chambers conduit 202. Thechambers FIG. 12 , thechamber 40 includes anelongated housing 40 h having aninlet 42 and anoutlet 44, a pair ofside walls 60, aposterior wall 70, and an open anterior portion including an aperture defining thecannulation port 40 p. Self-sealingmaterial 80 extends across the open anterior portion of thehousing 40 h (i.e., across theport 40 p). Alongitudinal passageway 46 is defined by thehousing 40 h and the self-sealingmaterial 80. The at least oneconduit 202 extends through thepassageway 46 and therefore defines a longitudinal fluid passageway 46' through the at least oneconduit 202. The self-sealingmaterial 80 and theconduit 202 may be adhered via a medical-grade adhesive 206. This configuration may prevent the two components from separating as a needle is inserted therethrough. The medical-grade adhesive 206 may also adhere theconduit 202 to thechamber housing 40 h. - The
chamber 30 may have a sim ilar or identical configuration. The portion of theAVG 200 including thechamber 30 is shown as including theouter veneer 150, although it will be understood that theouter veneer 150 will typically extend over at least a portion of theAVG 200 including thechamber 40. - Alternative chamber cross-section views are shown in
FIGS. 14 and 15 . Although theconduit 202 is shown extending through thechamber housings AVG 10 described above. The chamber housings 30 h, 40 h shown inFIGS. 14 and 15 are elongated along a center or a bottom portion of the housing, and may thereby assist in maintaining the cannulation ports in an upward-facing configuration both during and after tunneling in much the same way as the configurations illustrated inFIGS. 9 and 10 . - An
AVG 300 according to other embodiments is illustrated inFIG. 16 . The primary difference in this embodiment is that theAVG 300 includes only one cannulation chamber 30'. TheAVG 300 may include aconduit 202 extending through the housing of the chamber 30' in much the same way as described above in connection with theAVG 200. Alternatively, theAVG 300 may include first andsecond conduits AVG 10. That is, thefirst conduit 12 connects an artery and thechamber inlet 32 and thesecond conduit 22 connects thechamber outlet 34 and a vein. - The chamber 30' may have a length greater than above-described lengths for the
chambers FIG. 5 ) of between about 5 and about 90 degrees, between about 15 and about 90 degrees, between about 30 and about 80 degrees, and greater than about 40 degrees to accommodate placement in, for example, an upper arm of a subject. Theconduits 12, 14 (or equivalent portions of the conduit 202) may have a length L4 of between about 10 cm and about 20 cm and may also be trimmed to suit a particular application. At a portion of at least one of theconduits 12, 14 (or equivalent portions of the conduit 202) may be kink-proof or kink-resistant. As illustrated,beading material 58 is wrapped around a length L5 of theconduit 22 adjacent the chamber 30'. - An
AVG 400 according to other embodiments is shown inFIG. 17 . The primary difference in this embodiment is that theAVG 400 includes three ormore cannulation chambers 30". As illustrated, theAVG 400 includes 11chambers 30"; however, it will be appreciated that fewer or more chambers may be employed. Eachchamber 30" may include all the features described above in connection with thechambers chamber 30" includes ahousing 30"h having an inlet, an outlet and an open anterior portion defining acannulation port 30"p with self-sealing material extending across or adjacent the cannulation port. Thus, eachchamber 30" has a longitudinal passageway therethrough as described above. - Each
chamber 30" will generally have a shorter length L6 than as described above in the other embodiments. The length L6 may be between about 1 cm and about 7 cm, between about 1 cm and about 5 cm, and about 3 cm in various embodiments. - The
AVG 400 may include aconduit 202 extending through the longitudinal passageway eachchamber 30" in much the same way as described above in connection with theAVG 200. Thechambers 30" will generally be spaced closer together than in the embodiments described above. The length L7 of the spacing may be between about 0.25 cm and about 5 cm, between about 0.25 cm and about 2 cm, and between about 0.5 cm and about 1 cm in various embodiments. - The
AVG 400 may provide flexibility when being implanted in a subject. That is, theAVG 400 may be bent or otherwise manipulated to accommodate a particular implantation site. Also, the plurality of chambers have a generally large overall surface area of self-sealing material, thereby retaining the advantages described above. - An
AVG 500 according to other embodiments is illustrated inFIG. 18 . TheAVG 500 may include features described above in reference to theAVGs - Like the
AVG 200 shown inFIGS. 11-13 , theAVG 500 may have a reduced number of fluid (e.g., blood) contacting components. The chambers of theAVG 500 are constructed somewhat differently than the chambers of theAVGs - The
AVG 500 includes aconduit 202 having first and second end portions 12', 22'. Theconduit 202 may be formed of an inert biocompatible material such as ePTFE, polyurethane, Dacron, or the like. The first end portion 12' is configured to connect to an artery of a subject at an end 14' thereof, like theend 14 shown inFIG. 1 . The second end portion 22' is configured to connect to a vein of the subject at an end 24' thereof, much like theend 24 shown inFIG. 1 . In this regard, blood flows through theconduit 202 from the first end portion 12' to the second end portion 22'. - As illustrated, a pair of cannulation chambers 30'", 40'" are positioned in a spaced-apart relationship between the first and second end portions 12', 22' of the
conduit 202. The chambers 30'", 40'" may be identical or substantially identical. The chamber 30'" includes aninlet 32 and anoutlet 34. The chamber 40'" includes aninlet 42 and anoutlet 44. Theconduit 202 extends through the chamber 30'" from theinlet 32 to theoutlet 34. Theconduit 202 extends through the chamber 40'" from theinlet 42 to theoutlet 44. A middle portion 52' of theconduit 202 is disposed between the chambers 30'", 40'". - Each of the chambers 30'", 40'" includes an
elongated chamber body 210 that surrounds theconduit 202. Thechamber bodies 210 define therespective chamber inlets chamber outlets shield 208. Theshell 208 may be embedded in thechamber body 210. - A cross sectional view of the
chamber 30"' is shown inFIG. 19 . As illustrated, thechamber body 210 includes aninner layer 212 and anouter layer 214. Theinner layer 212 may be annular and define achamber passageway 213. Thechamber passageway 213 may have a longitudinal axis A4 that corresponds to a longitudinal axis A5 of the conduit 202 (e.g., a fluid flow passageway or path of the conduit 202). Theshell 208 may be disposed between theinner layer 212 and theouter layer 214. - Referring to
FIGS. 19 and 20 , theinner layer 212 may fit over theconduit 202. Theinner layer 212 may be molded around theconduit 202. Theinner layer 212 may be adhered or otherwise attached to theconduit 202. Theinner layer 212 is formed of a self-sealing material (e.g., but not limited to, silicone). - Turning to
FIGS. 19-21 , theinner layer 212 may be received in acavity 209 of theshell 208. Theshell 208 may be molded to theinner layer 212. Theshell 208 may be adhered or otherwise attached to theinner layer 212. Theshell 208 may generally have the shape of an open-ended semi-cylinder and therefore surround about 180 degrees of the outer circumference of theinner layer 212. Theshell 208 may be C-shaped or U-shaped. Theshell 208 includes a posterior wall 70' and opposing sidewalls 60' defining thecavity 209. Theshell 208 has a length that is at least a major portion of the length of theinner layer 212. In some embodiments, the length of theshell 208 and theinner layer 212 are substantially the same. Theshell 208 is formed of a substantially rigid biocompatible material (e.g., titanium or a substantially rigid polymer or composite). - Referring to
FIGS. 19 and 22 , theshell 208 and theinner layer 212 may be received in theouter layer 214. Theouter layer 214 may be molded around theinner layer 212 and/or theshell 208. Theinner layer 212 and/or theshell 208 may be adhered or otherwise attached to theouter layer 214. Theouter layer 214 may be formed of any suitable material; for example, a material that facilitates bonding or molding with theinner layer 212. The outer layer may be formed of a self-sealing material (e.g., but not limited to, silicone). - The
outer layer 214 includes acannulation port 216. In place, thecannulation port 216 exposes the self-sealing material of theinner layer 212. In some embodiments, theouter layer 214 can include an additional layer of self-sealing material across thecannulation port 216. - The
chamber body 210 may include cannulation port locating features. For example, thecannulation port 216 may include a raised perimeter orperimeter portion 218 such that the cannulation port can be tactilely and/or visually identified when theAVG 500 is implanted in a subject. That is, the raisedperimeter 218 may be visible through the skin of the subject and/or felt through the skin by medical personnel. - It will be understood that, like the other embodiments described above, when a dialysis needle is inserted through the
cannulation port 216 and the self-sealing material (e.g., the inner layer 212), the needle may be inhibited or prevented from extending through the shell 208 (e.g., the posterior or the side walls of the shell 208). - It will be appreciated that the
shell 208, theinner layer 212 and theouter layer 214 of thechamber housing 210 may be provided as an integrated chamber 30'" rather than assembled as described above. The chamber 30'" may then be fit onto a graft conduit, such as theconduit 202. For example, theconduit 202 may be received in the chamber passageway 213 (e.g., pulled through the chamber passageway 213). Thechamber 30"' may also be molded to theconduit 202 or otherwise attached (e.g., adhered) to theconduit 202. - Turning again to
FIG. 18 ,beading material 58 may be included on the outer periphery of the middle portion 52' of theconduit 202. Also, as illustrated,beading material 58 may be wrapped around a length L6 of theconduit 202 adjacent thechamber 30"' and/or the chamber 40'". In some embodiments, the length L6 is about 1 to 2 cm. - As illustrated in
FIG. 19 , theouter veneer 150 may be provided over at least a portion of theAVG 500. Although not shown inFIG. 18 , it will be understood that theouter veneer 150 will typically extend over at least a major portion of theAVG 500 including the chambers 30'" and 40'" and the middle portion 52' of theconduit 202. Theouter veneer 150 may also extend from the chambers 30'", 40'" toward or to the first and second end portion 12', 24' of theconduit 202. - The chambers 30'", 40'" may include a flattened bottom portion or
surface 220. As described above, such a configuration may inhibit malpositioning and/or twisting of the graft. The chambers/chamber bodies may have a domed or generally triangular shape when viewed from the end or cross-section. In some other embodiments, the chambers/chamber bodies may have a substantially circular cross-section, an elliptical cross-section or a generally oval cross-section. - Turning to
FIG. 23 , the chambers 30'", 40'" may be curved to have are angles A1, A2 in the same manner as described above in connection with thechamber 30. The arc angles A1 and A2 may be equal for a particular chamber 30'". The values of the arc angles A1, A2 may be as described above in connection with thechamber 30. For example, the angles A1 and A2 may be between about 10 and 30 degrees to facilitate placement in an upper extremity of a patient. - The chambers 30'" and 40'" each have a center portion or section and opposed end portions or sections (e.g., the
center portion 30 c and theend portions 30 e shown inFIG. 23 ). The chambers 30'" and 40'" may have the same dimensions as the dimensions of thechambers cannulation ports 216 may have the same dimensions as the dimensions of thecannulation ports conduit 202, including the first end portion 12', the second end portion 22' and the middle portion 52', may have the same dimensions and properties as theconduits - It is contemplated that the chambers described herein may be supplied separately from their associate conduit(s). For example, the chamber 30'" and/or the chamber 40'" may be provided to a clinician, who may then fit the chambers 30'" and/or 40'" to an off-the shelf graft conduit as needed for a particular application.
- It is also contemplated that various components described above may be supplied as a medical kit. For example, the chambers 30'" and/or 40"' (or the components thereof) may be supplied with the
conduit 202 for later assembly and use. - The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.
Claims (21)
1. An arteriovenous dialysis access graft configured to be implanted in a subject, com prising:
at least one flexible conduit having first and second end portions, wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the at least one conduit from the first end portion to the second end portion; and
at least one cannulation chamber positioned between the first end portion and the second end portion of the at least one conduit, the chamber com prising:
an elongated housing having an inlet at a first end thereof and an outlet at a second, opposed end thereof, a posterior wall, a pair of sidewalls, and an open anterior portion defining a cannulation port, wherein the cannulation port has a length that spans at least a major portion of a length of the housing;
a self-sealing material extending across the cannulation port; and
a longitudinal passageway defined by the housing and the self-sealing material that extends from the inlet to the outlet of the housing;
wherein the posterior wall and the sidewalls of the housing of the at least one chamber are configured such that, when a dialysis needle is inserted through the self-sealing material and the cannulation port, the needle is inhibited or prevented from extending through the posterior or the side walls of the housing.
2. The arteriovenous dialysis access graft of claim 1 , wherein:
the at least one cannulation chamber com prises first and second cannulation cham bers;
the at least one conduit comprises a middle portion between the first and second end portions; and
the first cham ber is positioned between the first end portion and the middle portion of the at least one conduit;
the second chamber positioned between the middle portion and the second end portion of the at least one conduit.
3. The arteriovenous dialysis access graft of claim 2 , wherein the at least one conduit extends through the longitudinal passageway of each chamber.
4. The arteriovenous dialysis access graft of claim 2 , wherein:
the at least one conduit comprises first, second and third flexible conduits, each conduit having a first and second end;
the first end of the first conduit is configured to connect to the artery of the subject and the second end of the first conduit is connected to the inlet of the first cham ber;
the first end of the second conduit is configured to connect to the vein of the subject and the second end of the second conduit is connected to the outlet of the of the second chamber; and
the first end of the third conduit is connected to the outlet of the first chamber and the second end of the third conduit is connected to the inlet of the second chamber.
5. The arteriovenous dialysis graft of claim 2 , wherein the first and second chambers, the middle portion of the conduit, and at least a portion of the first and second end portions of the conduit are covered by a veneer formed of a biocompatible material.
6. The arteriovenous dialysis access graft of claim 2 , wherein the at least one of the first and second chambers is curved such that the longitudinal passageway has an arc angle.
7. The arteriovenous dialysis access graft of claim 6 , wherein the arc angle is between about 5 and about 45 degrees to accommodate placement in an upper arm of the subject.
8. The arteriovenous dialysis access graft of claim 6 , wherein the arc angle is between about 5 degrees and about 60 degrees to accommodate placement in a forearm or lower extremity of the subject.
9. The arteriovenous dialysis graft of claim 2 , wherein the conduit and/or the chambers are formed of a biocompatible material.
10. The arteriovenous dialysis graft of claim 2 , wherein the self-sealing material comprises silicone.
11. The arteriovenous dialysis graft of claim 2 , wherein the at least one conduit comprises ePTFE.
12. The arteriovenous dialysis graft of claim 2 , wherein each chamber housing comprises at least one of a polymeric material and titanium.
13. The arteriovenous dialysis graft of claim 2 , wherein each chamber housing material provides tactile and/or audible feedback to an operator that the dialysis needle has contacted an interior portion of the posterior wall or one of the side walls.
14. The arteriovenous dialysis graft of claim 2 , wherein a bottom portion of each chamber is squared or flat to inhibit malpositioning and/or twisting of the graft.
15. An arteriovenous dialysis access graft configured to be implanted in a subject, com prising:
a flexible conduit defining a longitudinal flow passageway, the conduit having first and second end portions and a middle portion, wherein the first end portion is configured to connect to an artery of the subject and the second end portion is configured to connect to a vein of the subject such that blood flows through the longitudinal passageway of the conduit from the first end portion to the second end portion; and
first and second spaced-apart cannulation chambers with the conduit extending through each of the first and second cham bers, the first chamber positioned between the first end portion and the middle portion of the conduit, the second chamber positioned between the second end portion and the middle portion of the conduit, each chamber comprising:
an elongated chamber body surrounding the conduit, the chamber body comprising self-sealing material and a cannulation port that exposes the self-sealing material; and
an elongated shell embedded in the chamber body and extending generally parallel to the longitudinal flow passageway of the conduit, the shell including a posterior wall, a pair of sidewalls, and an open anterior portion facing the cannulation port of the chamber body;
wherein each shell is configured such that, when a dialysis needle is inserted through the cannulation port and the self-sealing material, the needle is inhibited or prevented from extending through the posterior or the side walls of the shell.
16. The arteriovenous dialysis graft of claim of claim 15 , wherein the chamber body includes an annular inner layer including the self-sealing material surrounding the conduit and an outer layer including the cannulation port around the inner layer, and wherein the shell is disposed between the inner and outer layers.
17. The arteriovenous dialysis graft of claim 15 , wherein the cannulation port includes a raised perimeter portion such that the cannulation port can be tactilely and/or visually identified.
18. The arteriovenous dialysis graft of claim 15 , wherein at least a major portion of a length of the middle portion of the conduit includes beading material.
19. The arteriovenous dialysis graft of claim 15 , wherein a portion of the conduit extending from the first chamber to the first end portion includes beading material and/or a portion of the conduit extending from the second chamber to the second end portion includes beading material.
20. The arteriovenous dialysis graft of claim 15 , wherein each chamber is curved to have an arc angle that is between about 10 and 30 degrees to accommodate placement in an arm of a subject.
21. The arteriovenous dialysis graft of claim 15 , wherein each chamber body has a flattened bottom to inhibit malpositioning and/or twisting of the graft.
Priority Applications (1)
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US17/970,332 US20230043946A1 (en) | 2011-03-16 | 2022-10-20 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
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US201161453211P | 2011-03-16 | 2011-03-16 | |
PCT/US2012/029449 WO2012125927A2 (en) | 2011-03-16 | 2012-03-16 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US14/027,986 US9585998B2 (en) | 2011-03-16 | 2013-09-16 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US15/450,523 US10420874B2 (en) | 2011-03-16 | 2017-03-06 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US16/580,423 US11504461B2 (en) | 2011-03-16 | 2019-09-24 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US17/970,332 US20230043946A1 (en) | 2011-03-16 | 2022-10-20 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
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US16/580,423 Continuation US11504461B2 (en) | 2011-03-16 | 2019-09-24 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
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US20230043946A1 true US20230043946A1 (en) | 2023-02-09 |
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US15/450,523 Active 2032-03-22 US10420874B2 (en) | 2011-03-16 | 2017-03-06 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US16/580,423 Active 2033-08-07 US11504461B2 (en) | 2011-03-16 | 2019-09-24 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US17/970,332 Pending US20230043946A1 (en) | 2011-03-16 | 2022-10-20 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
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US15/450,523 Active 2032-03-22 US10420874B2 (en) | 2011-03-16 | 2017-03-06 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
US16/580,423 Active 2033-08-07 US11504461B2 (en) | 2011-03-16 | 2019-09-24 | Arteriovenous graft for hemodialysis with puncture-resistant posterior and side walls |
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EP (1) | EP2686033B1 (en) |
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2012
- 2012-03-16 WO PCT/US2012/029449 patent/WO2012125927A2/en active Application Filing
- 2012-03-16 AU AU2012229032A patent/AU2012229032B2/en active Active
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AU2012229032A1 (en) | 2013-09-26 |
US9585998B2 (en) | 2017-03-07 |
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EP2686033B1 (en) | 2015-05-06 |
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AU2012229032B2 (en) | 2015-06-25 |
CA2829766C (en) | 2019-07-02 |
US20140018721A1 (en) | 2014-01-16 |
US11504461B2 (en) | 2022-11-22 |
WO2012125927A3 (en) | 2013-01-10 |
EP2686033A2 (en) | 2014-01-22 |
CA2829766A1 (en) | 2012-09-20 |
ES2540957T3 (en) | 2015-07-15 |
EP2686033A4 (en) | 2014-01-22 |
US20170173252A1 (en) | 2017-06-22 |
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