Methods and apparatus for arterial-venous connection

Abstract

Methods, apparatus, and kits for forming flow couplings between veins and arteries are provided. The apparatus may comprise a tubular body with a cutting tip at a distal end thereof. The lumen of the tubular body is pushed over two wires, one located in a vein, the other in an artery. As the tubular body is pushed over the wires, the wires can squeeze the vein and artery walls together, and the cutting tip slices adjacent openings in the vein and artery. The adjacent openings may form a natural fistula without additional measures taken to seal them together, or the adjacent openings may be connected with sutures, cauterizing, or the like to form a fistula.

Description

DISTAL.OOIWOMETHODS AND APPARATUS FOR ARTERIAL-VENOUS CONNECTIONBACKGROUND OF THE INVENTION

[0001] There are a variety of circumstances where it is beneficial to create a flow coupling between an artery and a vein. Accordingly, some procedures and devices have been developed to create such arterial-venous connections. For example, to perform hemodialysis in kidney failure patients the procedure may use a vein in the arm that has been coupled to an artery in the arm to increase flow in the vein to better support the procedure. Further improvements in these procedures remain desirable.

[0002] It should be noted that this Background is not intended to be an aid in determining the scope of the claimed subject matter nor be viewed as limiting the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above. The discussion of any technology, documents, or references in this Background section should not be interpreted as an admission that the material described is prior art to any of the subject matter claimed herein.SUMMARY OF THE INVENTION

[0003] Methods, apparatus, and kits for providing flow coupling between a vein and an artery are provided. Some embodiments of the invention are described and set forth below in the claims.

[0004] In some embodiments, an apparatus is provided comprising a body defining a longitudinal axis and comprising a lumen therethrough. A proximal portion of the body comprises a proximal lumen opening, and a distal portion of the body comprises a distal lumen opening. A distal tip is provided in the distal end of the body adjacent to the lumen distal opening, wherein at least a portion of the distal tip comprises an edge configured for cutting tissue. The apparatus further comprises a first wire having a first portion positioned in the lumen and a second portion extending distally out of the lumen from the distal lumen opening and a second wire having a first portion positioned in the lumen and a second portionextending distally out of the lumen from the distal lumen opening. In some embodiments, the distal edge surrounds the distal opening, and the distal opening is substantially circular in axial cross section. The first wire and the second wire may be substantially circular in axial cross section. The first wire may be characterized by a first diameter, and the second wire may be characterized by a second diameter. In some embodiments, the distal opening is characterized by a third diameter, and the third diameter is no more than 150% of the sum of the first diameter and the second diameter. The lumen may be the only lumen in the body. The body may comprise a wall formed from at least one spiral filament.

[0005] In some embodiments, a kit for forming an axial vein opening in a target vein portion and an axial artery opening in a target artery portion is provided. The kit may comprise a body defining a longitudinal axis and comprising a lumen therethrough. A proximal portion of the body comprises a proximal lumen opening, and a distal portion of the body comprises a distal lumen opening. A distal tip is provided in the distal end of the body adjacent to the lumen distal opening, wherein at least a portion of the distal tip comprises an edge configured for cutting tissue. The kit further comprises a first guidewire extendable through the at least one lumen and a second guidewire extendable through the at least one lumen alongside the first guidewire. The body may comprise a wall formed from at least one spiral filament. In some embodiments of the kit, the first wire is characterized by a first diameter, the second wire is characterized by a second diameter, and the distal opening is characterized by a third diameter. In some embodiments, the third diameter is no more than 150% of the sum of the first diameter and the second diameter. The kit may further comprise a needle. The needle may comprise an elongated needle body comprising a needle distal end and a needle proximal end, a sharp needle tip at the needle distal end configured for puncturing a wall of a vein and / or a wall of an artery adjacent to the vein, and a needle lumen extending from a distal opening at the distal end to a proximal opening at the proximal end configured to accommodate at least one of the first guidewire and the second guidewire. The kit may further comprise a dilator configured to facilitate advancement of the tubular body into the tissue and vascular system of a subjectDISTAL.OOIWO in a non-traumatic manner. The dilator may include a ring provided concentrically between the dilator and the cutting member, and configured to facilitate unhindered sliding of the cutting member over the dilator.

[0006] The above-described kit can be used in methods for causing peripheral vein arterialization. Such methods may comprise inserting the first guidewire into a target vein portion and inserting the second guidewire into a target artery portion. The body is then advanced over both the first and second guidewires until approximating or adjoining the vein wall and the artery wall juxtaposing thereto and further pushed over both the first and the second guidewires thereby gradually forming an axial vein opening along the vein wall simultaneously with an axial opening along the artery wall. Blood is allowed to flow from the artery to the vein through the axial artery opening and the axial vein opening for causing an arterialization of the vein in proximity to the axial vein opening. This method may comprise penetrating across a vein wall and a juxtaposing artery wall using the needle, wherein the first guidewire and / or the second guidewire is inserted via the needle, and the advancing is performed after removing the needle.

[0007] In some embodiments, a method for causing peripheral vein arterialization comprises penetrating at a first penetration point across a vein wall of a target vein portion and at a second penetration point an artery wall of a target artery portion located in juxtaposition to the target vein portion. From the points of penetration, gradually forming along longitudinal axes of the vein and artery, an axial vein opening along the vein wall together with an axial artery opening along the artery wall, and allowing blood to flow from the target artery portion to the target vein portion through the axial artery opening and the axial vein opening, for causing a natural arterialization of the target vein portion and / or a natural fistula coupling the target vein portion and the target artery portion. The gradually forming may result in two opposing elongated vein cut edges extending along the axial vein opening and two opposing elongated artery cut edges extending along the axial artery opening. The vein may be deformed or allowed to deform itself such that a first of the vein cut edges approximates or adjoins a first of the artery cut edges and a second of the vein cut edges approximates or adjoins a second of the artery cutDISTAL.OOIWO edges, thereby forming an elongated passage configured with a passage cross section greater than cross sections of each of the target vein portion and the target artery portion. In some embodiments, the first of the vein cut edges may be attached to the first of the artery cut edges and the second of the vein cut edges attached to the second of the artery cut edges to form a fistula, attaching may comprise suturing, cauterizing, coagulating, or some other attachment method. The gradually forming may include at least one of grooving, cutting, skiving, coring, and peeling of both the vein wall and the artery wall. The axial vein opening may be longer and / or wider than the axial artery opening. The gradually forming may be performed simultaneously on both the vein wall and the artery wall using a single tool and / or by a single stroke. The gradually forming may cause, include or follow approximating or adjoining the vein wall and the artery wall.

[0008] In other embodiments, a device for forming an axial vein opening in a target vein portion and an adjacent axial artery opening in a target artery portion may comprise an elongated body comprising a distal end and a proximal end and enclosing at least one lumen extending from a distal opening at the distal end to a proximal opening at the proximal end. A tissue manipulating head is provided at the distal end, and the at least one lumen, the distal opening, and the proximal opening are configured to accommodate together therethrough at least two guidewires. The tissue manipulating head includes a first portion configured to gradually form an axial vein opening in a vein wall of the target vein portion, when pushed thereagainst over a first guidewire extending through the at least one lumen into the target vein portion, and also includes a second portion configured to gradually form an axial artery opening in an artery wall of the target artery potion adjacent to the vein, when pushed thereagainst over a second guidewire extending through the at least one lumen into the target artery portion. The first portion may oppose the second portion in the tissue manipulating head. The tissue manipulating head may be configured to form the axial artery opening and the axial vein opening simultaneously, when pushed over the first and the second guidewires. The first portion of the tissue manipulating head may be configured as a blade portion configured for grooving, cutting, skiving, coring, and / or peelingDISTAL.OOIWO the vein wall, and / or the second portion of the tissue manipulating head may be configured as a blade portion configured for grooving, cutting, skiving, and / or peeling the juxtaposing artery wall. The tissue manipulating head may include a sharp, jagged, notched and / or tapered oval or circular edge which includes the first and second portions of the tissue manipulating head.

[0009] In another embodiment, a method for causing peripheral vein arterialization comprises gradually forming an axial vein opening along a vein wall of a target vein portion simultaneously with an axial artery opening along an artery wall of a target artery portion opposingly and in juxtaposition to the axial vein opening. Blood is then allowed to flow from the target artery portion to the target vein portion from the axial artery opening to the axial vein opening, thereby initiating a naturally occurring arterialization of the target vein portion. In this embodiment, the gradually forming is performed such that the vein wall enclosing the axial vein opening and the artery wall enclosing the axial artery opening deform into a natural fistula comprising the target vein portion and the target artery portion. The gradually forming may result in two opposing elongated vein cut edges extending along the axial vein opening and two opposing elongated artery cut edges extending along the axial artery opening. The vein cut edges and / or the artery cut edges may be deformed or allowed to deform such that a first of the vein cut edges approximates or adjoins a first of the artery cut edges and a second of the vein cut edges approximates or adjoins a second of the artery cut edges, thereby forming a unitary passage configured with a passage cross section greater than cross sections of each of the target vein portion and the target artery portion. In some embodiments, the gradually forming is accompanied by gradual approximation or adjoining of the vein wall and the artery wall.

[0010] In another embodiment, a method for causing vein arterialization comprises placing a first wire in a vein and a second wire in an artery, sliding a blade over or along the first and the second wires, and forcing the blade simultaneously against juxtaposing and opposing wall portions of the vein and the artery until gradually forming an axial cut or grooved opening in each of the wall portions. Blood may be then allowed to flow from the artery to the vein through the openings. TheDISTAL.OOIWO placing may follow accessing a lumen of the artery with a needle via a lumen of the vein. In some embodiments, the accessing includes locating a target vein portion of the vein, inserting the needle into a lumen of the target vein portion, locating a target artery portion of the artery using the needle from within the lumen of the target vein portion optionally using ultrasound imaging, and penetrating with the needle from the lumen of the vein into a lumen of the artery through a wall of the target vein portion and then through a wall of the target artery portion. In this embodiment, inserting the needle or locating the target artery portion may include or follow extending the first wire or an access wire through the lumen of the vein, passing the needle in the lumen of the vein over the first wire or the access wire, and removing the first wire or the access wire from the needle. In this embodiment, the placing may include inserting the second wire into the lumen of the artery via the needle, partially withdrawing the needle such that a tip thereof is positioned back in the lumen of the vein, and inserting the first wire into the lumen of the vein via the needle. In some embodiments, the second wire is inserted into the artery across both the opposing wall portions of the vein and the artery. In some embodiments, placing the first wire follows placing the second wire. In these methods the blade may extend distally from an elongated flexible body, may be oval or circular, and / or may circumferentially surround the first wire and the second wire. In some embodiments, the method includes rotating the blade during the forcing.

[0011] In another embodiment, a surgical device comprises a flexible tube having a circular cutting tip at a distal end thereof and two guidewires passing through a lumen thereof, wherein the guidewires and the cutting member are all movable laterally and longitudinally in relation to each other; wherein a distal tip of each of the guidewires is flexible and atraumatic; wherein the cutting edge is configured to advance over the guidewires with an optional rotating motion for facilitating advancement and cutting through thick and / or calcified arterial wall, wherein the guidewires are configured to extend through both proximal and distal openings of the lumen throughout the entire duration of the cutting tip advancement.DISTAL.OOIWO

[0012] In another embodiment, a method for causing a peripheral vein arterialization comprises extending a first elongated member in a vein, extending a second elongated member in an artery, forming a mutual pivot portion by holding together adjacent portions of the first and the second elongated members, and forcing the first elongated member to rotate about the mutual pivot portion towards the vein wall and the second elongated member to rotate about the mutual pivot portion towards the artery wall, in simultaneous scissor-like motion of the first and second elongated members, for forming an axial vein opening and an axial artery opening. The forcing may include shearing the vein wall and the artery wall between the first and / or the second elongated members during the forcing.

[0013] In another embodiment, a device for forming juxtaposing axial vein opening in a target vein portion and axial artery opening in a target artery portion comprises a tubular member comprising a distal end and a proximal end, and enclosing an at least one lumen extending from a distal opening at the distal end to a proximal opening at the proximal end. A pusher head is provided at the distal end. The at least one lumen, the distal opening, and the proximal opening, are configured to accommodate and snugly fit together therethrough a first and a second elongated member. The pusher head is configured to form a mutual pivot portion by holding together adjacent portions of the first and the second elongated members and the pusher head is configured to force the first elongated member to rotate about the mutual pivot portion towards the vein wall and the second elongated member to rotate about the mutual pivot portion towards the artery wall, in simultaneous scissor-like motion of the first and second elongated members, for forming an axial vein opening and an axial artery opening.

[0014] It is understood that various configurations of the subject technology will become apparent to those skilled in the art from the disclosure, wherein various configurations of the subject technology are shown and described by way of illustration. As will be realized, the subject technology is capable of other and different configurations and its several details are capable of modification in various other respects, all without departing from the scope of the subjectDISTAL.OOIWO technology. Accordingly, the summary, drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.BRIEF DESCRIPTION OF THE FIGURES

[0015] Various embodiments are discussed in detail in conjunction with the Figures described below, with an emphasis on highlighting the advantageous features. These embodiments are for illustrative purposes only and any scale that may be illustrated therein does not limit the scope of the technology disclosed. These drawings include the following figures, in which like numerals indicate like parts.

[0016] FIG. 1 A shows an artery and vein in the arm that may be connected for blood flow therebetween.

[0017] FIG. 1 B shows a generic vein and artery intended to be connected for blood flow therebetween.

[0018] FIGs. 2A (I) and (II) each show a vein and artery with an elongated member in the form of a wire installed in each.

[0019] FIGs. 2B (I) and (II) each show the vein, artery, and elongated members of FIG. 2A (I) and (II) with the additional illustration of a cutting tip being pushed over them.

[0020] FIGs. 2C (I) and (II) show a method and apparatus for creating a flow coupling between a vein and an artery according to some implementations of the inventions.

[0021] FIGs. 3 (I), (II), and (III) also illustrate methods of creating a flow coupling between a vein and an artery.

[0022] FIG. 4 illustrates an example cutting tool device suitable for the abovedescribed methods.

[0023] FIG. 5A shows a first exemplary cutting tool.

[0024] FIG. 5B shows a second exemplary cutting tool with a spiral filament sidewall.

[0025] FIG. 5C shows another example spiral filament sidewall.

[0026] FIGs. 5D and 5E show additional embodiments of tissue manipulating and / or cutting tips.DISTAL.OOIWO

[0027] FIG. 6 is an axial cross section illustrating exemplary dimensions of the tool elongated body and the wires in accordance with some embodiments.

[0028] FIG. 7 is an axial cross section of a tissue manipulating and / or cutting tip with two elongated members installed therein, one in a vein, and one in an artery.

[0029] FIGs. 8A, 8B, and 8C show tissue manipulating and / or cutting tips with internal and / or external spiral structures.

[0030] FIG. 9A is a flowchart of initial steps of an exemplary method of placing a first elongated member in a vein, and a second elongated member in an artery.

[0031] FIGs. 9B, 9C, 9D, 9E, and 9F illustrate each step of FIG. 9A.

[0032] FIG. 10A is a flowchart of the remaining steps of an exemplary method of placing a first elongated member in a vein, and a second elongated member in an artery.

[0033] FIGs. 10B, 10C, 10D, 10E, 10F and 10G illustrate each step of FIG. 10A.

[0034] FIG. 11A is a flowchart illustrating gradually forming cut juxtaposing openings in the vein and artery walls.

[0035] FIGs. 1 1 B and 11 C illustrate the steps of FIG. 1 1 A.

[0036] FIG. 12A is a flowchart of the final steps of an exemplary embodiment of creating an arterio-venous flow connection.

[0037] FIG. 12B illustrates one of the steps of FIG. 12A.

[0038] FIG. 13 shows another device and method for creating cuts for forming a flow coupling between a vein and an artery.

[0039] FIGs. 14A, 14B, and 14C, and 14D show axial cross sections at different locations of FIG. 13.

[0040] FIGs. 15A, 15B, and 15C show a method of creating a flow coupling between a vein and an artery with an alternative embodiment.

[0041] FIG. 16 shows an axial cross section of a tissue manipulating and / or cutting tip with an oval cross section.

[0042] FIG. 17 shows an axial cross section of a tissue manipulating and / or cutting tip with non-round elongated members.DISTAL.OOIWODETAILED DESCRIPTION

[0043] The following description and examples illustrate some exemplary implementations, embodiments, and arrangements of the disclosed invention in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this invention that are encompassed by its scope. Accordingly, the description of a certain example embodiment should not be deemed to limit the scope of the present invention.

[0044] Referring to FIG. 1 A, it is sometimes desirable to produce a flow connection between a vein and an artery, sometimes referred to as vein arterialization. For example, a fistula between a vein and an artery in a patient’s forearm / wrist may be surgically created to provide relatively robust access to a patient’s vasculature for hemodialysis. FIG. 1 A illustrates as an example a fistula flow coupling in the forearm / wrist of a patient. These are sometimes surgically created for hemodialysis access purposes.

[0045] In these and other related procedures, as shown in FIG. 1 B, a target vein portion and a target artery portion may be selected to create such a flow coupling. Although in FIG. 1 B and many of the other illustrations of veins and adjacent arteries herein the vein is shown above the artery and in some figures appearing to be closer to the skin in depth than the artery, in actual anatomy it is most common for both to be at approximately the same depth beneath the skin and be laterally adjacent or otherwise near each other. Accordingly, if the terms “under,” “over,” “upper,” “lower” and the like are used herein these uses are being made for easy reference to the apparent arrangement in the figures and should not be construed to imply any particular relationship to a patient’s anatomy such as the location of the skin. In some cases herein, the walls of the subject vein and artery may be referred to as the remote vein wall 63, the adjacent vein wall 64, the adjacent artery wall 68, and the remote artery wall 69, where the term “remote” refers to the vein and artery walls opposite to the fistula or other flow coupling that is to be created, and the term “adjacent” refers to the vein and artery walls that are near and / or abut each other that are to be cut to form the fistula.DISTAL.OOIWO

[0046] In general, a method for causing peripheral vein arterialization may comprise penetrating across a vein (V) wall of a target vein portion and an artery (A) wall of a target artery portion located in juxtaposition to the target vein portion, gradually forming an axial vein opening along the vein wall together with an axial opening along the artery wall, and allowing blood to flow from the target artery portion to the target vein portion through the axial artery opening and the axial vein opening, for causing a naturally occurring arterialization of the target vein portion and / or a naturally occurring fistula comprising of the target vein portion and the target artery portion. As used herein, “natural” or “naturally occurring” when applied to a fistula or flow coupling means no externally applied energy or additional materials are used to join the walls of the vein and artery being coupled for flow therebetween. Examples of non-naturally occurring flow couplings or fistulas would include those wherein the vein and artery walls are at least partially connected with sutures or sealed with the application of heat, electromagnetic, or other energy to artificially seal the vessel walls together in the vicinity of the flow coupling.

[0047] As shown in FIG 2A, a vein guidewire 16 and an artery guidewire 14 may be placed in a vein and nearby, adjacent, and / or juxtaposed artery respectively. The guidewires exit the body of the subject optionally through a common opening 52 in the skin (FIG. 2A (II)) and a common opening 54 on the upper vein wall just below the skin layers. Artery guidewire 14 further extends into artery A through a lower vein opening 56 and an upper artery opening 58. An example method of installing these guidewires as shown in FIG. 2A is described below with reference to FIGs. 9A through 10G. Once installed as shown in FIG. 2A a device 20 with an elongated body 22 and a tissue manipulating head 26 may be advanced over the two guidewires 14, 16 and into the patient through openings 52 and 54 as shown in FIG. 2B. The tissue manipulating head 26 may comprise a cutting tip (42, FIG. 4).

[0048] As the device 20 is advanced over the guidewires 14, 16, the head 26 of the tool extends through opening 52 in the skin and opening 54 in the remote (upper) vein wall. Then the artery oriented (lower) portion 42A (see FIGs. 2B, 2C,DISTAL.OOIWO and 3) of the head 26 extends through the opening 56 in the adjacent (lower) vein wall 64 and through opening 58 in the adjacent (upper) artery wall and extends under both vein wall segment 64 and artery wall segment 68 while the vein oriented (upper) portion 42V of the head 26 does not extend through opening 56 or opening 58 and extends over adjacent (lower) vein wall segment 64 and adjacent (upper) artery wall segment 68 as shown in FIG. 20. The guidewire portions already accommodated within device 20 are optionally held tight with each other, so when device 20 advances along the guidewires the additional guidewire portions accommodated thereinside are forced towards each other, thereby forcing adjacent tissues entrapped therebetween to approximate each other and / or compress. This brings the adjacent vein wall 64 and adjacent artery wall 68 together as also shown in FIG. 20 and the tissue manipulating head 26 cuts the adjacent artery wall 68 and adjacent vein wall 64 in at least approximately corresponding positions as it is advanced further along the vein and artery walls.

[0049] The top panel of FIG. 3 shows end cross sectional views corresponding generally to the side view of FIG. 20. As shown in the middle panel of FIG. 3, the cutting may result in two opposing elongated vein cut edges 36, 38 extending along the axial vein opening and two opposing elongated artery cut edges 32, 34 extending along the axial artery opening. These edges may be forced to deform or they may deform on their own to be closely adjacent and / or adjoin to form a passage cross section 35 and may form a naturally occurring fistula. The cross section 35 may be larger than the original diameters of the vein and artery. In some cases, the natural fistula configurations of panel (II) of FIG. 3 are sufficient to perform the clinically desired function of increasing the flow / diameter of the vein. In other cases, it may be desired to take additional measures to seal edges 36 and 38 to edges 32 and 34 respectively. This may be done with sutures, cauterization, coagulation or other methods to form a more stable fistula. The natural fistulas of FIG. 3 panel (II) created by the methods and devices described herein may therefore be referred to as “staging” fistulas in that they can perform the flow coupling functions of a fistula by themselves with the additional possibility of stabilizing the fistula with additional sealing measures if desired either at the timeDISTAL.OOIWO of original cutting or later after the initially created natural fistula is evaluated for performance and stability.

[0050] As shown in Fig. 4, the device 20 may comprise an elongated body 22 with a lumen 28 extending proximally through an optional handle 24. Whether provided with a handle or not, the wires 14, 16 can exit the lumen at a proximal portion of the device through an end hole or possibly a side hole. The distal tip 42 may comprise a sharp bladed edge around all or part of the circumference thereof to simultaneously cut the vein wall and the artery wall as it is advanced leftward such as shown in FIG. 2D.

[0051] FIG. 5A shows a first implementation of device 20 comprising an elongated body 22 comprising a sidewall 48 surrounding a lumen 28 that defines a longitudinal axis 46a. The sidewall 48 has a constant inner diameter and an outer diameter that tapers inward to terminate in a sharp distal cutting tip 42. The sidewall may be rigid or may have some flexibility and may be made of metal or a polymer.

[0052] FIG. 5B shows a second implementation of device 20 comprising an elongated body comprising a torque-able side wall 49. Such a torque-able side wall may, for example, comprise one or more spiral wound filaments. In these embodiment, the tissue manipulating head 26 may be a separately manufactured part that is affixed to the end of the spiral filament sidewall by any suitable method such as with adhesive or by laser welding. FIG. 5C shows an example multi-layer torque-able tube material.

[0053] The torque-able sidewall has the advantage that it can provide flexibility for the elongated body 22 of the device 20 while at the same time allowing torque around the longitudinal axis 46c that is applied on the proximal end of the elongated body 22 to be converted to torque around the longitudinal axis 46b at the distal end of the elongated body 22 at and near the cutting tip 42 even when the elongated body is somewhat curved or bent and the longitudinal axis 46c at the proximal end of the elongated body 22 is not parallel to the longitudinal axis 46b at the tissue manipulating head 26. With these embodiments, when the device 20 is positioned as shown in FIG. 2C, rotational torque can be manually applied byDISTAL.OOIWO the surgeon at or near the proximal portion of the elongated body 20 in order to rotate the tissue manipulating head 26 at the distal portion of the elongated body to facilitate the cutting action of the distal tip 42 as the device 20 is advanced leftward.

[0054] FIGs. 5D and 5E show additional alternative constructions for the distal section of the tissue manipulating head 26 that forms the cutting edge 42. In some embodiments, the tissue manipulating head 26 is configured to reduce the potential for damage to tissues that are not intended to be cut during the formation of the arterio-venous connection.

[0055] In the embodiment of FIG. 5D, the cutting edge 142 at the distal tip is formed by a bevel 43 extending between the outer diameter (OD) and the inner diameter (ID) of the tissue manipulating head 26. To minimize damage to additional tissues, this bevel may be relatively steep with respect to the transverse plane, producing a relatively blunt beveled tip. As examples, FIGs. 5A and 5B are examples with a more extended taper from the OD to the ID, whereas FIG. 5D illustrates a blunter flat bevel configuration. The angle 41 between the bevel 43 and the transverse plane may be less than 45 degrees, and may in some embodiments be between 7 degrees and 20 degrees, with about 10 degrees having been found suitable in some implementations.

[0056] In the embodiment of FIG. 5E, the cutting edge is formed by a short protruding shoulder 53 localized around the ID. The shoulder 53 may extend distally less than the wall thickness of the tissue manipulating head 26.

[0057] FIG. 6 is an axial plan view of device 20 with two wires installed. In some embodiments, the respective sizes of the lumen 28 and the wires 14, 16 are such that the wires are relatively tightly spaced within the lumen 28. The beneficial functional aspects of this are described below with reference to FIG. 7. Although tightly spaced, it is also important that the elongated body 22 be capable of smoothly and easily sliding along the wires 14, 16 during use, so there must still be suitable clearance between the wires 14, 16, and the inner side wall of the lumen 28. It has been found suitable in some embodiments for the sum of the two wire diameters WD1 + WD2 to be between 70 and 90 percent of the inner diameterDISTAL.OOIWOID of the elongated body. Another expression suitable for non-round cross sections is that the total cross-sectional area of the two wires is between 25 and 40 percent of the cross-sectional area of the lumen 28. In one specific embodiment suitable for performing arterio-venous connection on radial veins, the ID of the device (the lumen 28 diameter) is optionally between 1.0 and 1.2 mm, the wires each have a diameter of 0.4 to 0.5 mm (e.g. two 0.018 inch nitinol guidewires), and the outer diameter OD is 1 .3 to 1 .6 mm.

[0058] Referring now to FIG. 7, these dimensions provide easy and efficient cutting for arterio-venous flow couplings for many vessels. As shown in FIG. 7, when the head 26 is being advanced, the constriction of the two wires at the entrance of the lumen 28 at the distal tip 42 of the device should be tight enough that the wires dig into and deform the inner surfaces of the vessel walls. This can press and / or squeeze the vessel walls together, fixing them in place as the head 26 is advanced and is performing the cutting action. This helps prevent the device from pushing and stretching the vessels as a whole in the longitudinal direction when the device is pushed along the wires to perform the cutting. During this process, the vessel walls are squeezed together at the distal tip of the elongated body 22, the distal cutting edge 42 cuts along the vessel walls, and the fixed together portions of the vein wall segment 64 and the artery wall segment 68 are sliced off of the vein and artery respectively and enter into and are retained in the lumen 28. The device therefore can remove a strip of compressed adjacent artery and vein wall having a significant width rather than merely creating adjacent single slices through the vessel walls. This helps form the natural fistula configuration of the left side of panel (II) in FIG. 3. During the advancing, the device can be manually rotated by the surgeon, typically back and forth, to facilitate the cutting function.

[0059] FIGs. 8A, 8B, and 8C illustrate tissue manipulating heads with internal and / or external spiral structures that can facilitate the advancement of the tissue manipulating head 26 along the vessel walls while making the cuts. In these implementations, spiral structures are provided that can facilitate advancement when the tissue manipulating head is rotated. In FIG. 8A, the tissue manipulating head has one or more internal spiral grooves 45, e.g. rifling. With this embodiment,DISTAL.OOIWO the head 26 pulls the tissue compressed between the wires proximally into the lumen 28 of the tool when the head 26 is rotated in the appropriate direction during advancement of the head 26 along the vessel walls. FIGs. 8B and 80 show spiral structures on the outside of the tissue manipulating head, which can also facilitate head 26 advancement under rotation. FIG. 8B shows an external spiral structure comprising protrusions 47 forming an auger type head. FIG. 80 shown an external spiral structure comprising grooves 51 forming a drill bit type head. A tissue manipulating head 26 could have spiral structures on the inside, outside, or both.

[0060] There are a variety of ways to place the guidewires into an adjacent artery and vein as shown in FIG. 2A. One simple method is to insert a needle through the skin, the remote vein wall, the adjacent vein wall, and the adjacent artery wall in an initial common needle insertion. This places the needle fully through the vein with the distal tip in the artery. The artery wire can then be inserted through the needle into the artery. The needle can then be partially withdrawn until the distal tip of the needle is in the vein rather than the artery. The vein wire can then be inserted through the needle (with the artery wire still present therein) and into the vein. The needle can then be withdrawn from the patient, leaving the vein wire and the artery wire in place. This technique can also be performed in an opposite order, where the needle is initially inserted through the artery with the distal tip in the vein, and the wires are installed first in the artery and then in the vein. These techniques have drawbacks at least in that a relatively large bore needle is required that can hold two guidewires at the same time and it is difficult or impossible to verify correct needle distal tip placement in both the vein and the artery during the procedure. FIGs. 9A-10G describe an optional alternative procedure for installing the two guidewires as shown in FIG. 2A that doesn’t suffer from these drawbacks.

[0061] FIGs. 9-12 are flowcharts describing acts that may be performed to create an arterio-venous flow connection in accordance with some embodiments. FIGs. 9 and 10 are directed to the creation of the guidewire configuration shown in FIG. 2A. FIGs 1 1 and 12 are directed to the cutting and forming of the flow connection. Although presented as a series of separate flowcharts, it will be appreciated thatDISTAL.OOIWO they may be followed one after the other in the complete method for fistula formation.

[0062] Referring now to FIGs. 9A through 9F, FIG. 9A is a flowchart of acts that may be used to first install two guidewires in the vein. The method begins at block 81 , where a cannulated beveled tip needle is inserted into the vein as shown in FIG. 9B. Once proper placement is confirmed by detecting blood flow up the needle, at block 82 a first guidewire is inserted into the vein through the needle as shown in FIG. 5C. Because the vein size may be small, it is beneficial to use a small diameter needle to make this puncture, and such a needle may be too small to fit a second wire. It has therefore been found advantageous to use a larger diameter but flexible polymer sheath to insert the second wire into the vein. Accordingly, at block 83, the needle is removed from the vein leaving the first guidewire in place and a sheath is placed into the vein over the first guidewire. This is illustrated in FIG. 9D. Then, at block 84, a second guidewire is inserted into the vein through the sheath, illustrated in FIG. 9E. At block 85, the sheath can then be removed, leaving the two guidewires behind in the vein as illustrated in FIG. 9F.

[0063] FIG. 10A is a flowchart showing an exemplary method of getting one of the two wires in the vein as shown in FIG. 9F to have one wire in the vein and one in the artery. Turning now to FIG. 10A, at block 86 the needle (or a new needle if desired) is threaded over one of the two guidewires installed in the vein as shown in FIG. 10B. Threading the needle over one of the previously installed wires ensures that the need goes back through the same holes previously made. It may be noted from FIG. 10B that this re-insertion of the needle may be performed upside down with the bevel of the needle tip pointing down with respect to the direction of needle insertion to minimize any new hole production during this reinsertion. Then at block 87 the wire that the needle was threaded over is withdrawn as shown in FIG. 10C. The needle may then be rotated to place the bevel of the tip upward in its normal puncture configuration as shown in FIG. 10D and at block 88 the needle is inserted through the adjacent vein and artery walls to enter the artery as shown in FIG. 10E. At this point, correct placement of the needle tip intothe artery can be confirmed by drawing some blood up through the needle. After this confirmation, at block 89 the previously withdrawn wire (or a new wire) may be re-inserted through the needle but now into the artery instead of the vein as shown in FIG. 10F. At block 90 the needle is removed, leaving behind one wire installed in the vein and one wire installed in the artery as shown in FIG. 10G and also 2A.

[0064] FIG. 11 A is a flowchart illustrating the cutting process with the tool. In block 91 , the cutting tool is placed over both wires as illustrated in FIG. 11 B and 2B and as described in detail above. At block 92, the adjacent vein and artery walls are held together, optionally compressed together as described above, and the tissue manipulating head is advanced along the vessel walls to perform the cuts along the vessel walls as shown in FIG. 1 1 C and 20 and as also discussed in detail above.

[0065] FIG. 12A is a flowchart illustrating fistula formation following the cuts of block 92 of FIG. 1 1 A. Referring now to FIG. 12A, after advancing the tissue manipulating head 26 a desired amount along the vessels, the tool can be partially withdrawn, allowing the adjacent vessel walls to open and artery to vein flow to occur. At this point, the amount of flow can be evaluated under visualization such as with ultrasound. If the flow is less than desired, the tool can be advanced further to create a longer cut until a desired flow is achieved. At block 94, the tool can be removed from the subject and flow through the fistula can be established, as shown in FIG. 12B. At block 95, the wires can be removed. It has been found that having the wires remain installed for a few minutes helps stabilize the vein and artery against each other, helping establish a robust flow from the artery to the vein.

[0066] In the embodiments described above, the guidewires 14, 16 are fundamentally used to align and compress the artery and vein walls so the tissue manipulating head 26 can accurately cut along adjoining portions of the vein and artery. In some embodiments, the wires themselves may be used alternatively or additionally to perform the vein and artery wall cuts. Some of these embodiments are described further below.DISTAL.OOIWO

[0067] Referring now to FIG. 13, in one such embodiment, a first elongated member 17 extends in a vein V and a second elongated member 15 extends in an artery A. These first and second elongated members can be inserted as described above with reference to FIGs. 2A through 2C. Also similar to the above-described embodiments, the first and second elongated members 17, 15 further extend into a tubular member through which they exit the vein, artery, and patient’s body. In the embodiment of FIG. 13, the tubular member comprises a proximal portion 57 and a pusher head 52. The pusher head 52 comprises a portion, which may be at or at least close to the distal tip of the device, that is small enough to hold the first and second elongated members close together. This may create a pivot portion designated 54 in FIG. 13 around which the first elongated member 17 and second elongated member 15 may be forced to rotate toward each other as indicated in FIG. 13 by arrows 56a and 56b as the distal tip of the pusher head 52 is advanced (leftward in FIG. 13) along the elongated members 15, 17 and the vein and artery walls. This rotation may in some embodiments be a scissor-like motion. Thus, the first elongated member 17 rotates toward the vein wall and the second elongated member 15 rotates toward the artery wall.

[0068] The stiffness of the elongated members 15, 17 causes this rotation to continue into and through the vein and artery walls such that the elongated members themselves slice through the vein and artery walls at a location ahead of the distal tip of the pusher head 52, for example near where the arrow heads of arrows 56a and 56b meet in FIG. 13. In these embodiments, the pusher head 52 need not perform any cutting of the vessel walls. Instead, it may be used as a tool to just force the elongated members together to cut through the vein and artery walls in a manner analogous to cutting with scissors

[0069] FIGs. 14A through 14C illustrate axial cross sections at the locations of the corresponding dotted lines shown in FIG. 7. FIG. 14D is a larger view of FIG. 14G, both of which show the elongated members 15 and 17 having sliced through the vein and artery walls ahead of the distal tip of the pusher head 52. To get the elongated members forced together enough to slice through the vein and artery walls, the inner diameter of at least a portion of the pusher head 52.DISTAL.OOIWO

[0070] FIGs. 15A through 15C illustrate an embodiment where the pusher head 52 can be sequentially advanced multiple times during a procedure, effectively performing a series of scissor cuts with the elongated members. In this embodiment the pusher head is formed as an inner sleeve for the rest of the tubular member 57. FIG. 15A shows the device after first being inserted over the elongated members 15, 17 to the needle hole between the two. As shown in FIG. 15B, the pusher head can then be advanced out of the lumen of the tubular member as illustrated by the arrow 62, forcing the elongated members 15, 17 together and through the vein and artery walls as a first cut having an extent approximately equal to the amount that the pusher head 52 extends out of the tubular member 57. As shown in FIG. 15C, the tubular member 57 can then be advanced forward over the pusher head 52 to put the device in a relative configuration similar to that shown in FIG. 15A but advanced further along the vein and artery walls. The steps of FIGs. 15B and 15C can be repeated a desired number of times to create adjoining vein and artery openings of a desired length.

[0071] Advancing the pusher head 52 forward from the tubular member 57 can be done by linear sliding or by rotational motion. For rotational advancement, the inner surface of the tubular member 57 and the outer surface of the pusher head 52 can be threadably coupled. With such a coupling, the pusher head 52 could be advanced by holding the tubular member rotationally still and rotating the pusher head or by holding the pusher head rotationally still and rotating the tubular body. It will also be appreciated that the pusher head 52 could include the auger or drill bit configurations shown in FIGs. 8B and 8C, either of which may or may not include sharp edges to perform some of the cutting function as well.

[0072] FIGs. 16 and 17 illustrate possible alternative configurations of the pusher head and elongated members. FIG. 16 shows an oval option for the distal tip of the pusher head 52. Whether round, oval, or some other shape, it is advantageous for the largest diameter of the pusher head near the distal tip is no more than 20% greater than the sum of the largest diameters of the first and second elongated members, 15, 17. Furthermore, the axial cross section of the elongated members need not be round. For example, one or more flat surfaces may be present. FIG.DISTAL.OOIWO17 shows a half-circle cross section which may provide edges or corners 66 and 68 that may efficiently perform the cutting function on the vein and artery walls. As also shown in FIG. 17, for this embodiment, a septum 74 may be provided near the distal tip of the pusher head 52 keep the elongated members appropriately oriented. Other cross-sectional shapes for the elongated members such as rectangle, triangle, or a star shape may also be used.

[0073] In some implementations, a dilator may be provided that is configured to facilitate advancement of the cutting tool 20 into the tissue and vascular system of a subject in a non-traumatic manner. The dilator may optionally include a ring provided concentrically between the dilator and the cutting member and may be configured to facilitate unhindered sliding of the cutting member over the dilator. This may help prevent the cutting tip of the device 20 from cutting the dilator when it is disengaged after advancing it into the vein.Hemodialysis Application Example

[0074] In hemodialysis procedures, blood is withdrawn from the patient, cleaned of toxins, waste, and excess fluids, and returned to the body. In these procedures, a vein is accessed to withdraw blood for routing to the dialysis machine and to return blood from the dialysis machine to the vein. In about 80% of dialysis patients, a central venous catheter (CVC) is implanted in the vena cava to withdraw and return the blood. Although high flow can be established with a CVC, these devices are associated high rates of complications, infections, thrombosis, failure, and even patient death. For some patients with healthy and relatively large veins in their arm, a fistula between an artery in the arm and the vein in the arm can be created, generating sufficient blood flow in the vein to allow dialysis to be performed with needles periodically inserted into and removed from the vein for each procedure. Because this does not involve any permanent or semi-permanent implant of a device in the patient, it exhibits much lower rates of complication, infections, and the like. It is accordingly a highly preferred method of venous access for dialysis. However, a large portion of the dialysis patient population does not have veins in the arm of sufficient diameter to support the blood flow needed for this access method. Such patients are required to have a CVC implanted.DISTAL.OOIWO

[0075] It has been found that the methods and apparatus described herein can enlarge veins significantly by creating artery to vein flow in the arm. For example, when the cephalic vein and the radial artery are the target vein and target artery respectively, average vein diameter increases of over 60% have been observed in a cohort of 32 clinical study patients. In this study, prior to the procedures described herein being performed, only 13% of the study participants had vein diameters suitable for wrist fistula-based hemodialysis, whereas after the procedure, 77% of the study participants had vein diameters suitable for wrist fistula-based hemodialysis.

[0076] The systems and methods described herein can therefore significantly reduce the need for CVC based hemodialysis for the benefit of patients, hospitals, and physicians alike.

[0077]

[0078] General Interpretive Principles for the Present Disclosure

[0079] Various aspects of the novel systems, apparatuses, and methods are described herein with reference to the accompanying drawings. The teachings disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the novel systems, apparatuses, and methods disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, a system or an apparatus may be implemented, or a method may be practiced using any one or more of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such a system, apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect disclosed herein may be set forth in oneor more elements of a claim. Although some benefits and advantages of the preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to particular benefits, uses, or objectives. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

[0080] With respect to the use of plural vs. singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singu lar / plu ral permutations may be expressly set forth herein for sake of clarity.

[0081] When describing an absolute value of a characteristic or property of a thing or act described herein, the terms “substantial,” “substantially,” “essentially,” “approximately,” and / or other terms or phrases of degree may be used without the specific recitation of a numerical range. When applied to a characteristic or property of a thing or act described herein, these terms refer to a range of the characteristic or property that is consistent with providing a desired function associated with that characteristic or property.

[0082] In those cases where a single numerical value is given for a characteristic or property, it is intended to be interpreted as at least covering deviations of that value within one significant digit of the numerical value given.

[0083] If a numerical value or range of numerical values is provided to define a characteristic or property of a thing or act described herein, whether or not the value or range is qualified with a term of degree, a specific method of measuring the characteristic or property may be defined herein as well. In the event no specific method of measuring the characteristic or property is defined herein, and there are different generally accepted methods of measurement for the characteristic or property, then the measurement method should be interpreted as the method of measurement that would most likely be adopted by one of ordinary skill in the art given the description and context of the characteristic or property. In the further event there is more than one method of measurement that is equally likely to be adopted by one of ordinary skill in the art to measure the characteristicDISTAL.OOIWO or property, the value or range of values should be interpreted as being met regardless of which method of measurement is chosen.

[0084] It will be understood by those within the art that terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are intended as “open” terms unless specifically indicated otherwise (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.).

[0085] It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and / or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).

[0086] In those instances where a convention analogous to “at least one of A, B, and C” is used, such a construction would include systems that have A alone, B alone, C alone, A and B together without C, A and C together without B, B and C together without A, as well as A, B, and C together. It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings,should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include A without B, B without A, as well as A and B together.”

[0087] Various modifications to the implementations described in this disclosure can be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the claims, the principles and the novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0088] Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

[0089] The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and / or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

Claims

DISTAL.OOIWOClaims1 . An apparatus comprising: a body defining a longitudinal axis and comprising a lumen therethrough; a proximal portion of the body comprising a proximal lumen opening; a distal portion of the body comprising a distal lumen opening; a distal tip in the distal end of the body adjacent to the lumen distal opening, wherein at least a portion of the distal tip comprises an edge configured for cutting tissue; a first wire having a first portion positioned in the lumen and a second portion extending distally out of the lumen from the distal lumen opening; a second wire having a first portion positioned in the lumen and a second portion extending distally out of the lumen from the distal lumen opening.

2. The apparatus of claim 1 , wherein the first wire has a third portion extending proximally out of the proximal lumen opening and wherein the second wire has a third portion extending proximally out of the proximal lumen opening.

3. The apparatus of any one of claims 1 or 2, wherein the distal edge surrounds the distal opening, and wherein the distal opening is substantially circular in axial cross section.

4. The apparatus of any one of claims 1 through 3, wherein the first wire and the second wire are substantially circular in axial cross section.

5. The apparatus of claim 4, wherein the first wire is characterized by a first diameter, the second wire is characterized by a second diameter, wherein the distal opening is characterized by a third diameter, and wherein the third diameter is no more than 150% of the sum of the first diameter and the second diameter.

6. The apparatus of any one of claims 1 through 5, wherein the lumen is the only lumen of the body.

7. The apparatus of any one of claims 1 through 6, wherein the body comprises a wall comprising a metal.

8. The apparatus according to any one of claims 1 through 7, wherein the body comprises a wall formed from at least one spiral filament.DISTAL.OOIWO9. The apparatus according to claim 8, wherein the body comprises a braided wall.

10. A kit for forming anaxial vein opening in a target vein portion and a juxtaposed axial artery opening in a target artery portion, the kit comprising: a body defining a longitudinal axis and comprising a lumen therethrough; a proximal portion of the body comprising a proximal lumen opening; a distal portion of the body comprising a distal lumen opening; a distal tip in the distal end of the body adjacent to the lumen distal opening, wherein at least a portion of the distal tip comprises an edge configured for cutting tissue; a first guidewire extendable through the at least one lumen; and a second guidewire extendable through the at least one lumen alongside the first guidewire.1 1. The kit according to claim 10, wherein the body comprises a wall formed from at least one spiral filament.

12. The kit according to claim 1 1 , wherein the body comprises a braided wall.

13. The kit according to any one of claims 6 through 8, wherein the first wire is characterized by a first diameter, the second wire is characterized by a second diameter, wherein the distal opening is characterized by a third diameter, and wherein the third diameter is no more than 150% of the sum of the first diameter and the second diameter.

14. A kit according to any one of claims 10 through 13, further comprising a needle, wherein the needle comprises: an elongated needle body comprising a needle distal end and a needle proximal end, a sharp needle tip at the needle distal end configured for puncturing a wall of a vein and / or a wall of an artery adjacent to the vein, and a needle lumen extending from a distal opening at the distal end to a proximal opening at the proximal end configured to accommodate at least one of the first guidewire and the second guidewire.DISTAL.OOIWO15. The kit according to any one of claims 10 through 14, further comprising a dilator configured to facilitate advancement of the cutting member into the tissue and vascular system of a subject in a non-traumatic manner.

16. The kit according to claim 15, wherein the dilator includes a ring provided concentrically between the dilator and the cutting member, and configured to facilitate unhindered sliding of the cutting member over the dilator17. A method for causing peripheral vein arterialization using a kit according to any one of claims 10 through 16, the method comprising: inserting the first guidewire into a target vein portion; inserting the second guidewire into a target artery portion; advancing the body over both the first and second guidewires until approximating or adjoining the vein wall and the artery wall juxtaposing thereto; pushing the body over both the first and the second guidewires thereby gradually forming an axial vein opening along the vein wall simultaneously with an axial opening along the artery wall; and allowing blood to flow from the artery to the vein through the axial artery opening and the axial vein opening, for causing an arterialization of the vein in proximity to the axial vein opening.

18. A method according to claim 17 when dependent on claim 14, further comprising penetrating across a vein wall and a juxtaposing artery wall using the needle, wherein the first guidewire and / or the second guidewire is inserted via the needle, and the advancing is performed after removing the needle.

19. A method for causing peripheral vein arterialization, the method comprising: penetrating at a first penetration point across a vein wall of a target vein portion and at a second penetration point an artery wall of a target artery portion located in juxtaposition to the target vein portion; from the points of penetration, gradually forming along longitudinal axes of the vein and artery, an axial vein opening along the vein wall together with an axial artery opening along the artery wall; and allowing blood to flow from the target artery portion to the target vein portion through the axial artery opening and the axial vein opening, for causing a naturalDISTAL.OOIWO arterialization of the target vein portion and / or a natural fistula coupling the target vein portion and the target artery portion.

20. The method according to claim 19, wherein the gradually forming results in two opposing elongated vein cut edges extending along the axial vein opening and two opposing elongated artery cut edges extending along the axial artery opening.

21. The method according to claim 20, further comprising deforming the vein cut edges and / or the artery cut edges, or allowing the vein cut edges and / or the artery cut edges to deform such that a first of the vein cut edges approximates or adjoins a first of the artery cut edges and a second of the vein cut edges approximates or adjoins a second of the artery cut edges, thereby forming an elongated passage configured with a passage cross section greater than cross sections of each of the target vein portion and the target artery portion.

22. The method according to claim 21 , further comprising attaching the first of the vein cut edges to the first of the artery cut edges and the second of the vein cut edges to the second of the artery cut edges to form a fistula.

23. The method according to claim 22, wherein the attaching comprises suturing.

24. The method according to claim 22, wherein the attaching comprises cauterizing or coagulating.

25. The method according to any one of claims 19 through 24, wherein the target vein portion comprises a portion of a radial or cephalic vein.

26. The method according to claim 25, wherein the target artery portion comprises a portion of a radial artery.

27. The method according to any one of claims 19 though 26, wherein the penetrating includes puncturing by pushing a needle through the vein wall and the artery wall.

28. The method according to any one of claims 19 through 27, wherein the gradually forming includes at least one of grooving, cutting, skiving, coring, and peeling of both the vein wall and the artery wall.

29. The method according to any one of claims 19 through 28, wherein the axial vein opening is longer than the axial artery opening.DISTAL.OOIWO30. The method according to any one of claims 19 through 29, wherein the gradually forming is performed simultaneously on both the vein wall and the artery wall using a single tool and / or by a single stroke.

31. The method according to any one of claims 19 through 30, wherein the gradually forming causes, includes or follows approximating or adjoining the vein wall and the artery wall.

32. The method according to any one of claims 19 through 31 , wherein the axial vein opening is longer and / or wider than the axial artery opening.

33. A device for forming an axial vein opening in a target vein portion and an adjacent axial artery opening in a target artery portion, the device comprising: an elongated body comprising a distal end and a proximal end, and enclosing at least one lumen extending from a distal opening at the distal end to a proximal opening at the proximal end; and a tissue manipulating head provided at the distal end; wherein the at least one lumen, the distal opening and the proximal opening, are configured to accommodate together therethrough at least two guidewires; wherein the tissue manipulating head includes a first portion configured to gradually form an axial vein opening in a vein wall of the target vein portion, when pushed thereagainst over a first guidewire extending through the at least one lumen into the target vein portion; and wherein the tissue manipulating head includes a second portion configured to gradually form an axial artery opening in an artery wall of the target artery potion adjacent to the vein, when pushed thereagainst over a second guidewire extending through the at least one lumen into the target artery portion.

34. A device according to claim 33, wherein the first portion opposes the second portion in the tissue manipulating head.

35. A device according to any one of claims 33 or 34, wherein the tissue manipulating head is configured to form the axial artery opening and the axial vein opening simultaneously, when pushed over the first and the second guidewires.

36. A device according to any one of claims 33 through 35, wherein the first portion of the tissue manipulating head is configured as a blade portion configured forDISTAL.OOIWO grooving, cutting, skiving, coring, and / or peeling the vein wall, and / or the second portion of the tissue manipulating head is configured as a blade portion configured for grooving, cutting, skiving, and / or peeling the juxtaposing artery wall.

37. A device according to any one of claims 33 through 36, wherein the tissue manipulating head includes a sharp, jagged, notched and / or tapered oval or circular edge which includes the first and second portions of the tissue manipulating head.

38. The device according to any one of claims 33 through 37, wherein the tissue manipulating head extends distally from an elongated flexible body.

39. A method for causing peripheral vein arterialization, the method comprising: gradually forming an axial vein opening, along a vein wall of a target vein portion, simultaneously with an axial artery opening, along an artery wall of a target artery portion, opposingly and in juxtaposition to the axial vein opening; and allowing blood to flow from the target artery portion to the target vein portion from the axial artery opening to the axial vein opening, thereby initiating a naturally occurring arterialization of the target vein portion; wherein the gradually forming is performed such that the vein wall enclosing the axial vein opening and the artery wall enclosing the axial artery opening deform into a natural fistula comprising the target vein portion and the target artery portion.

40. The method according to claim 39, wherein the gradually forming results in two opposing elongated vein cut edges extending along the axial vein opening and two opposing elongated artery cut edges extending along the axial artery opening.41 . The method according to any one of claims 39 through 40, further comprising deforming the vein cut edges and / or the artery cut edges, or allowing the vein cut edges and / or the artery cut edges to deform such that a first of the vein cut edges approximates or adjoins a first of the artery cut edges and a second of the vein cut edges approximates or adjoins a second of the artery cut edges, thereby forming a unitary passage configured with a passage cross section greater than cross sections of each of the target vein portion and the target artery portion.

42. The method according to any one of claims 39 through 41 , wherein the gradually forming is accompanied by gradual approximation or adjoining of the vein wall and the artery wall.DISTAL.OOIWO43. A method for causing vein arterialization, the method comprising: placing a first wire in a vein and a second wire in an artery; sliding a blade over or along the first and the second wires; forcing the blade simultaneously against juxtaposing and opposing wall portions of the vein and the artery until gradually forming an axial cut or grooved opening in each of the wall portions; and allowing blood to flow from the artery to the vein through the openings.

44. The method according to claim 43, wherein the placing follows accessing a lumen of the artery with a needle via a lumen of the vein.

45. The method according to claim 44, wherein the accessing includes: locating a target vein portion of the vein; inserting the needle into a lumen of the target vein portion; locating a target artery portion of the artery using the needle from within the lumen of the target vein portion optionally using ultrasound imaging; penetrating with the needle from the lumen of the vein into a lumen of the artery through a wall of the target vein portion and then through a wall of the target artery portion.

46. The method according to claim 45, wherein the inserting the needle or the locating the target artery portion includes or follows: extending the first wire or an access wire through the lumen of the vein; passing the needle in the lumen of the vein over the first wire or the access wire; and removing the first wire or the access wire from the needle.

47. The method according to claim 46, wherein the placing includes: inserting the second wire into the lumen of the artery via the needle; partially withdrawing the needle such that a tip thereof is positioned back in the lumen of the vein; and inserting the first wire into the lumen of the vein via the needle.

48. The method according to any one of claims 43 through 47, wherein the second wire is inserted into the artery across both the opposing wall portions of the vein and the artery.DISTAL.OOIWO49. The method according to any one of claims 43 through 48, wherein the placing of the first wire follows the placing of the second wire.

50. The method according to any one of claims 43 through 49, wherein the blade extends distally from an elongated flexible body.51 .The method of any one of claims 43 through 50, wherein the blade is oval or circular.

52. The method of any one of claims 43 through 51 , wherein the blade circumferentially surrounds first wire and the second wire.

53. The method of any one of claims 43 through 52, comprising rotating the blade during the forcing.

54. A surgical device, comprising a flexible tube having a circular cutting tip at a distal end thereof and two guidewires passing through a lumen thereof, wherein the guidewires and the cutting member are all movable laterally and longitudinally in relation to each other; wherein a distal tip of each of the guidewires is flexible and atraumatic; wherein the cutting edge is configured to advance over the guidewires with an optional rotating motion for facilitating advancement and cutting through thick and / or calcified arterial wall, wherein the guidewires are configured to extend through both proximal and distal openings of the lumen throughout the entire duration of the cutting tip advancement.

55. The surgical device according to claim 54, further comprising a dilator configured to facilitate advancement of the cutting member into the tissue and vascular system of a subject in a non-traumatic manner.

56. The surgical device according to claim 55, wherein the dilator includes a ring provided concentrically between the dilator and the cutting member, and configured to facilitate unhindered sliding of the cutting member over the dilator.

57. A method for causing a peripheral vein arterialization, the method comprising: extending a first elongated member in a vein; extending a second elongated member in an artery; forming a mutual pivot portion by holding together adjacent portions of the first and the second elongated members; andDISTAL.OOIWO forcing the first elongated member to rotate about the mutual pivot portion towards the vein wall and the second elongated member to rotate about the mutual pivot portion towards the artery wall, in simultaneous scissor-like motion of the first and second elongated members, for forming an axial vein opening and an axial artery opening.

58. The method according to claim 57, wherein the forcing includes shearing the vein wall and the artery wall between the first and / or the second elongated members during the forcing.

59. The method according to any one of claims 57 through 58, comprising allowing blood to flow from the artery to the vein through the axial artery opening and the axial vein opening, for causing a natural arterialization of the target vein portion and / or a natural fistula comprising the target vein portion and the target artery portion.

60. The method according to any one of claims 57 through 59, wherein the first elongated member and / or the second elongated member includes or is formed as a wire having resistance to bending sufficient for causing the forming of the axial vein opening and the axial artery opening.

61. The method according to any one of claims 57 through 60, wherein the holding together and / or the forcing includes pushing a tubular member over both the first and the second elongated members, and wherein the tubular member has an inner dimension sized for forcing the first and the second elongated members to align and extend against each other during the pushing the tubular member over.

62. The method according to claim 61 , wherein the inner dimension includes a maximal inner diameter no greater than 20% more than the sum of maximum outer diameters of the first and the second elongated members.

63. The method according to any one of claims 57 through 62, wherein the first and / or the second elongated members have a maximum outer diameter between 0.1 mm and 1 mm.

64. The method according to any one of claims 57 through 63, wherein the holding together and / or the forcing is performed on the first and / or the second elongated members within a body of the patient.DISTAL.OOIWO65. The method according to any one of claims 57 through 64, wherein the holding together and / or the forcing is performed on the first and / or the second elongated members within the vein or the artery.

66. The method according to any one of claims 57 through 65, wherein the extending of the first and / or the second elongated member includes curving or allowing curving of the first elongated member in the vein and / or the second elongated member in the artery, wherein the forming and / or the forcing includes straightening of the curved first and / or second elongated member.

67. The method according to any one of claims 57 through 66, wherein the target vein portion is of a cephalic vein.

68. The method according to any one of claims 57 through 67, wherein the axial vein opening is longer than the axial artery opening.

69. The method according to any one of claims 57 through 68, wherein the forcing is performed simultaneously on both the vein wall and the artery wall.

70. The method according to any one of claims 57 through 69, wherein the forcing results in two opposing elongated vein cut edges extending along the axial vein opening and two opposing elongated artery cut edges extending along the axial artery opening.

71. The method according to any one of claims 57 through 70, further comprising deforming the vein cut edges and / or the artery cut edges, or allowing the vein cut edges and / or the artery cut edges to deform such that a first of the vein cut edges approximates or adjoins a first of the artery cut edges and a second of the vein cut edges approximates or adjoins a second of the artery cut edges, thereby forming a unitary passage configured with a passage cross section greater than cross sections of each of the target vein portion and the target artery portion.

72. The method according to any one of claims 57 through 71 , further comprising attaching the first of the vein cut edges to the first of the artery cut edges and the second of the vein cut edges to the second of the artery cut edges for forming a fistula.DISTAL.OOIWO73. The method according to any one of claims 57 through 72, wherein the forcing causes, includes or follows approximating or adjoining the vein wall and the artery wall.

74. A device for forming juxtaposing axial vein opening in a target vein portion and axial artery opening in a target artery portion, the device comprising: a tubular member comprising a distal end and a proximal end, and enclosing an at least one lumen extending from a distal opening at the distal end to a proximal opening at the proximal end; and a pusher head provided at the distal end; wherein the at least one lumen, the distal opening and the proximal opening, are configured to accommodate and snugly fit together therethrough a first and a second elongated member; wherein the pusher head is configured to form a mutual pivot portion by holding together adjacent portions of the first and the second elongated members; and wherein the pusher head is configured to force the first elongated member to rotate about the mutual pivot portion towards the vein wall and the second elongated member to rotate about the mutual pivot portion towards the artery wall, in simultaneous scissor-like motion of the first and second elongated members, for forming an axial vein opening and an axial artery opening.

75. The device according to claim 74, wherein the pusher head is configured to form the axial artery opening and the axial vein opening simultaneously, when pushed over the first and the second guidewires.

76. The device according to any one of claims 74 through 75, wherein the pusher head includes a sharp portion configured for grooving, cutting, skiving, coring, and / or peeling the vein wall and / or the artery wall.

77. The device according to any one of claims 74 through 76, wherein the pusher head includes a sharp, jagged, notched and / or tapered oval or circular edge.

78. The device according to any one of claims 74 through 77 , wherein the tubular member is flexible and / or plastically deformable.DISTAL.OOIWO79. The device according to any one of claims 74 through 78, wherein the first elongated member and / or the second elongated member includes or is formed as a wire having resistance to bending sufficient for causing the forming of the axial vein opening and the axial artery opening.

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