US20040243095A1 - Methods and apparatus for inserting multi-lumen spit-tip catheters into a blood vessel - Google Patents

Abstract

Methods and apparatus are disclosed for inserting flexible, multi-lumen catheters into blood vessels, and in particular, for inserting flexible, split-tip catheters into blood vessels. The invention accomplishes these objects by temporarily stiffening each catheter lumen and tip independently through use of intra-catheter stiffener elements disposed within the catheter lumens. This provides means for advancing the catheter/stiffeners assembly through a subcutaneous tunnel, and over a plurality of guidewires until a distal tip of the catheter is at a desired position within the vessel. The intra-catheter stiffener elements are sufficiently stiffening to allow advancing the catheter over guidewires, but sufficiently flexible to allow bending and looping of the catheter for proper placement within the vessel.

Description

BACKGROUND OF THE INVENTION
• The invention relates to methods and apparatus for inserting a catheter into a body cavity and, more particularly, though not exclusively, to methods and apparatus for inserting a multi-lumen split-tip hemodialysis catheter into a blood vessel for hemodialysis.[0001]
• Multi-lumen catheters are desirable for various treatment applications such as hemodialysis where fluid extraction and infusion occur simultaneously. These multi-lumen catheters provide a single catheter application having multiple lumen channels each supporting independent flow, thus precluding the need for inserting multiple catheters or multiple-catheter assemblies. Further, because a patient might require frequent dialysis, often only days apart, it is desirable to secure placement of the catheter for extended periods of time. Extended placement, however, requires extreme catheter flexibility to avoid damage to the vessel and permit the catheter to move in the blood flow to minimize the possibility of the catheter remaining in pressure contact with the wall of the vessel for prolonged periods.[0002]
• Unfortunately, the desired flexibility of these catheters presents insertion difficulties. For example, simply advancing the catheter over a guidewire is very difficult since the catheter lacks sufficient stiffness to slide easily through the vessel wall and into the blood vessel to the desired location. Flexible catheters present additional difficulties associated with subcutaneous tunneling and placement.[0003]
• Known insertion methods and assemblies attempt to overcome, or at least mitigate, these insertion difficulties by stiffening the catheter temporarily during the insertion process. For example, one known method involves temporarily inserting a rigid tubular applicator into one of the lumens. This permits the stiffened catheter/applicator assembly to be passed over a guidewire into a desired position, at which point the applicator can be removed. For example, U.S. Pat. No. 5,405,341 attempts to solve the problem with a single rigid applicator that is designed for insertion into one lumen but also passes through a portion of the second lumen (at the distal end of the instrument) to effectively stiffen the two lumens of the catheter together during insertion. This approach is cumbersome, at best, and presents additional difficulties in maneuvering the instrument. Further, this temporary rigid applicator approach, however, is poorly suited for placement of a catheter having a split at its distal end into two or more separate lumens (e.g., to further isolate a fluid extraction lumen from a return infusion lumen) because only one tip can be secured.[0004]
• Hence, there exists a need for better and more effective methods and apparatus for insertion of flexible catheters into vessels.[0005]
SUMMARY
• The invention provides methods and apparatus for inserting flexible, multi-lumen catheters into blood vessels, and in particular, for inserting flexible, split-tip catheters into blood vessels. The invention accomplishes these objects by temporarily stiffening each catheter lumen and tip independently through use of intra-catheter stiffener elements disposed within the catheter lumens. This provides means for advancing the catheter/stiffeners assembly through a subcutaneous tunnel, and over a plurality of guidewires until a distal portion of the catheter is at a desired position within the vessel.[0006]
• The intra-catheter stiffener elements are sufficiently stiffening to allow advancing the catheter over guidewires, but also sufficiently flexible to allow bending and looping of the catheter for proper placement within the vessel. Further, the intra-catheter stiffener elements prevent catheter kinking during the insertion process. In one embodiment, the intra-catheter stiffener elements have tapered distal ends which can facilitate entry of the catheter/stiffeners assembly into a blood vessel and/or assist in dilating the blood vessel.[0007]
• One aspect of the invention provides methods and apparatus for inserting an antegrade tunneled, split-tip, hemodialysis catheter into a blood vessel. A distal portion of each of a plurality of guidewires is disposed in a blood vessel at a first location, generally in proximity to the vessel in which a portion of the catheter is to be placed. A subcutaneous tunnel is formed between the first location and a second location where a proximal end of the catheter can extend from the patient. An intra-catheter stiffener element is inserted into the proximal end of each catheter lumen until it extends beyond the distal end of that catheter lumen. The intra-catheter stiffener element can be releasably coupled, following insertion, to the proximal end of its respective catheter lumen via, for example, a mating luer assembly. Each guidewire can be inserted into to a distal end of a lumen in a respective intra-catheter stiffener element until that guidewire extends from the proximal end of that intra-catheter stiffener element. The catheter can then be advanced over the guidewires and into the blood vessel. Alternatively, the catheter can be advanced over the guidewires until a distal end of the catheter is adjacent to the vessel, at which point the catheter and guidewires can be advanced together into the vessel until the distal end of the catheter is at a desired location therein. Twisting the catheter while simultaneously advancing it along the guidewires can facilitate placement of the catheter into the vessel.[0008]
• In another aspect, the methods and apparatus of the invention provide for inserting a retrograde tunneled hemodialysis catheter into a blood vessel. A distal portion of each of a plurality of guidewires is inserted into a blood vessel at a first location generally as described above. An intra-catheter stiffener element is placed in each catheter lumen until it extends from a distal end of the catheter, and can be releasably connected to the proximal end of its respective catheter lumen, as noted above. A proximal end of each guidewire is threaded through the distal end of a lumen of each intra-catheter stiffener element until the guidewire extends beyond the proximal end of that stiffener element. The catheter is advanced over the guidewires, optionally using a twisting motion, until a distal portion of the catheter is disposed at a desired location within the vessel, or alternatively, the catheter can be advanced until its distal end is adjacent to the vessel, at which point the catheter and guidewires can be advanced together until the distal end of the catheter is disposed at a desired location within the vessel. The guidewires are removed from the catheter lumens. A subcutaneous tunnel is then formed between the first location and a second location, and the proximal end of the catheter is passed through the first location until it extends from the second location. (If the stiffener elements have not previously been removed, they can be removed from the catheter body following passage of the catheter through the tunnel.) An access port is connected to the proximal end of each of the catheter lumens allowing fluid connection with a treatment device, such as a hemodialysis infuser.[0009]
• In a related aspect, the methods and kits of the present invention can provide for dilating the desired vessel subsequent to inserting the distal portion of a first guidewire. For example, a size 6-French sheath/dilator can be threaded over the first guidewire. Further guidewires can then be inserted into the expanded vessel, or through a lumen in the sheath and into the vessel. After placement of the guidewires into the vessel, the dilator or sheath can be removed.[0010]
• In a further related aspect, the methods provide for tunneling between the first and second location by using a pointed stylet. A distal end of a pointed stylet can be inserted through the skin at the second location and pushed toward the first location until the distal end extends therefrom. The distal end of the catheter is removably attached to a proximal end of the stylet. The stylet is then pulled from the first location until the distal end of the catheter extends therefrom, to facilitate an antegrade tunneled catheter.[0011]
• Alternatively, a pointed distal end of a stylet can be inserted through the skin at the first location and pushed until it extends from the second location. The proximal end of the catheter can be removably attached to the proximal end of the stylet. The stylet is then pulled back toward the second location until the proximal end of the catheter extends therefrom. The catheter is then released from the stylet, thus positioning a retrograde tunneled catheter. To facilitate movement of the catheter within the tunnel, the proximal end of the catheter having mating lures or other coupling features can be removed or severed prior to attachment to the stylet. After tunneling the catheter, fluid couplings or other attachments can be disposed to the proximal end of the lumens.[0012]
• Preferably, the vessel is expanded to accommodate placement of the distal portion of the catheter in the vessel. Vessel dilators of increasing size can be sequentially inserted into the vessel for this purpose. For example, a size 12-French dilator followed by a size 14-French, which is then followed by a size 16-French dilator, can be inserted into the vessel before advancing the catheter along the guidewires. In other embodiments, fewer (or more) dilators of different sizes can be used. Differing size and number of vessel dilators can be used corresponding to the catheter chosen for the desired application. Use of intra-catheter stiffener elements can preclude use of vessel dilators sized larger that the catheter since the stiffener elements and the catheter itself can provide vessel dilation.[0013]
• Another aspect of the invention provides for apparatus, in the form of a kit, to insert a multi-lumen catheter into a blood vessel. The kit comprises guidewires each adapted to have a distal portion inserted into a blood vessel. A plurality of intra-catheter stiffener elements preferably having tapered distal ends are also provided, each having a lumen extending along its length sized to accommodate a guidewire, and each having an outside diameter sized to be slidably disposed within a lumen of the catheter. The intra-catheter stiffener elements can be provided in one or more predetermined lengths corresponding to a length of a catheter and its lumens selected for a particular use, or can be of the same length. Further, the intra-catheter stiffeners can be provided with mating devices, such as lures, disposed at a proximal end correspond with mating connectors disposed at a proximal end of the catheter lumens.[0014]
• One or more vessel dilators can also be provided in the kit, each corresponding in size to a particular application. For example, a size 6-French sheath/dilator can be provided to dilate the vessel to accommodate a plurality of guidewires. A size 12-French, 14-French, as well as a size 16-French, dilator can be provided to dilate the vessel to accommodate the distal tip of the catheter.[0015]
• The present invention is applicable in the field of hemodialysis, among others, for inserting a multi-tip catheter into a blood vessel. The methods and apparatus provide for insertion of a split-tip catheter without using a tearable sheath and avoid the problems associated with prior art approaches of split tip catheter insertion over a single guidewire.[0016]
BRIEF DESCRIPTION OF THE INVENTION
• These and other objects, advantages and features of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:[0017]
• FIG. 1 is a schematic, partially cutaway, side view of a hemodialysis catheter insertion system according to the invention;[0018]
• FIG. 2 is a schematic illustration of an initial step of a method according to the invention in which a distal portion of a first guidewire is inserted in a vessel;[0019]
• FIG. 3 is a schematic illustration of another step of the method of the invention in which a blood vessel dilating sheath and a distal portion of a second guidewire are inserted in a vessel;[0020]
• FIG. 4 is a schematic illustration of another step of the method in which an antegrade catheter is disposed in a subcutaneous tunnel between a first location and a second location according to the invention;[0021]
• FIG. 5 is a schematic illustration of another step of the method in which the first guidewire is threaded through a first lumen of a catheter assembly according to the invention, in which the catheter assembly has an intra-catheter stiffener element disposed in each lumen of the catheter;[0022]
• FIG. 6 is a schematic illustration of another step of the method in which the second guidewire is threaded through the second lumen of the catheter assembly to a point where two loops of guidewire remain to facilitate placement of the distal end of the catheter in the vessel;[0023]
• FIG. 7 is a schematic illustration of another step of the method in which the catheter assembly has been advanced along the guidewires until the distal portion of the catheter is positioned within the vessel at a desired location;[0024]
• FIG. 8 shows the catheter of FIG. 7 with the intra-catheter stiffener elements and guidewires removed;[0025]
• FIG. 9 is a schematic illustration showing a step of a method according to the invention wherein a retrograde catheter is shown having a distal end disposed in a vessel;[0026]
• FIG. 10 is a schematic illustration showing a further step of the method wherein the catheter has been subcutaneously tunneled subsequent;[0027]
• FIG. 11 shows the catheter with fluid-couplers installed; and[0028]
• FIG. 12 shows a kit according to the invention for installing catheters such as those described above.[0029]
DETAILED DESCRIPTION OF THE INVENTION
• In FIG. 1 a[0030]catheter system10 according to the invention is shown having acatheter body12 with twointernal lumens14A and14B. Thecatheter body12 has a “split-tip”distal end16 in which the body (and lumens) separate into two distal tip portions,18A and18B. The split tips can, but need not have one or more side ports20A and20B, in fluid communication with one or the other of the lumens to facilitate blood removal and return, respectively, during hemodialysis. Alternatively, or in conjunction with side ports, the distal ends can be open to provide fluid passageways for blood removal and return. Theproximal end22 of the catheter body can also be split into separate segments22A and22B and terminates with twoaccess ports28A and28B, which can include couplings, such luer-locks or the like, to couple the catheter to a hemodialysis machine in which blood is circulated and purified. The overall system or kit of the invention can also include twointra-catheter stiffener elements24A and24B and twoguidewires26A and26B (shown within therespective lumens14A and14B). Thecatheter body12 is typically a very flexible silicone, polyurethane or other biocompatible composition (e.g., having a stiffness in the range of about 65 to about 85 durometers). Preferably, theintra-catheter stiffener elements24A and24B are composed of a stiffer form of polyethylene or other biocompatible material. In addition to stiffening the assembly, the stiffener elements can also help to prevent kinking of the catheter during insertion.
• The[0031]catheter system10 of FIG. 1 provides for insertion of the distal end of the multi-lumen, split-tip,flexible catheter body12 into a blood vessel using the intra-catheter stiffener elements and guidewires, as will be explained below. Briefly, a distal portion of each guidewire is disposed at a desired position within the vessel. An intra-catheter stiffener element having a tapered tip to facilitate insertion into the vessel and to provide catheter stiffening is slidably disposed along the length of each catheter lumen until it extends beyond the distal tip of that catheter lumen. A proximal end of each guidewire is threaded through a distal end of a lumen extending along each of the intra-catheter stiffener elements. The catheter is then advanced over the guidewires and into the blood vessel. Alternatively, the catheter can be advanced over the guidewires until the distal end is adjacent to the vessel, at which point the catheter and guidewires can be advanced together into the blood vessel. The guidewires and intra-catheter stiffener elements are then removed from the catheter. The methods and application kit described can be used for any split-tip catheter, and are particularly useful for insertion of subcutaneously tunneled hemodialysis catheters.
• A method of insertion according to the invention will next be described in connection with FIGS. 2-8. The procedure involves not only inserting the catheter tips into a blood vessel but also forming a subcutaneous tunnel below a patient's skin to secure the catheter in place and is sometimes described as antegrade or forward insertion. It will be appreciated, however, that the methods described herein can be used for inserting catheter tips into a blood vessel where tunneling is not necessary or desired.[0032]
• FIG. 2 schematically shows an initial step of a method according to the invention in which a distal portion of a[0033]first guidewire26A is inserted in avessel4 of apatient2. The entry location6 of theguidewire26A is referred to herein as the “first location” or the “venotomy site.” This first location is typically a surgical incision that provides access to the desired blood vessel which typically includes the internal or external jugular, femoral or subclavian vein, and the vena cava, for example. In one preferred embodiment, the blood vessel chosen for catheter placement can be the right side internal jugular vein.
• In FIG. 3, a blood vessel sheath/[0034]dilator30 is shown inserted over thefirst guidewire26A to dilate the vessel. The distal portion of asecond guidewire26B is then inserted in thevessel4 via the sheath/dilator30.
• With reference to FIG. 4, a[0035]subcutaneous tunnel40 is formed (before or after the insertion ofguidewires26A and26B) to anchor the catheter body in place and provide two remote ports for coupling the two lumens of the catheter to a dialysis machine. In FIG. 4, acatheter body12 of an antegrade catheter has been disposed in asubcutaneous tunnel40 between the first (venous access) location6 and a second (exit)location32, such that the distal end of the instrument including thesplit tips18A and18B extend from the first location. Prior to insertion, each of the lumens ofcatheter body12 has been fitted with a hollow, tubular, intra-catheter stiffener element or liner,24A and24B, respectively.
• In FIG. 5, the[0036]first guidewire26A is threaded through a first lumen of the catheter assembly (i.e., through the lumen ofintra-catheter stiffener element24A). In FIG. 6, thesecond guidewire26B is threaded through the second lumen of the catheter assembly (i.e., through the lumen of intra-catheter stiffener element24B). Each of the guidewires is advanced through the catheter assembly to a point where two short loops of guidewire remain to facilitate placement in the vessel.
• As shown in FIG. 7, the catheter assembly is then advanced along the guidewires until the[0037]distal end16 of the catheter is positioned at a desired position within the vessel. In a preferred embodiment, the catheter is advanced over the guidewires until the distal end is adjacent to the vessel, and then the catheter and the guidewires can be advanced together until the distal end of the catheter is positioned at a desired position within the vessel. Theguidewires26A and26B can then be removed by withdrawing them via theproximal end22 of the catheter body. Likewise, theintra-catheter stiffener elements24A and24B can be removed (either subsequent to the guidewires or at the same time).
• Advantageously, this method precludes using a vessel dilator larger than the catheter/stiffeners assembly for placement of the catheter within the vessel since the intra-catheter stiffener elements and the catheter itself provide vessel dilation.[0038]
• FIG. 8 shows the catheter of FIG. 7 with the intra-catheter stiffener elements and guidewires removed. The venous access incision is then closed and the catheter is secured subcutaneously (e.g., via an implanted cuff and/or sutures).[0039]
• Although the above detailed description has been presented in connection with an antegrade insertion, it should be clear that the methods and systems of the present invention are equally useful in retrograde or reverse insertions (where the catheter body is passed through the subcutaneous tunnel from venotomy site to the remote exit location).[0040]
• Thus, a method according to the invention for insertion of a retrograde catheter will next be described. An initial step for insertion of a retrograde catheter begins with placement of guidewires within the vessel as described above in connection with FIGS. 2 and 3.[0041]
• FIG. 9 illustrates a step of the method wherein the[0042]catheter body12 has each of the lumens fitted with a hollow, tubular, intra-catheter stiffener element or liner,24A and24B, respectively. The intra-catheter stiffener elements can have a coupler at a proximal end that releasably couple to a mating coupler at a proximal end of the respective catheter lumen.Guidewires26A and26B are threaded through the lumens of the catheter assembly as described above in FIGS. 5 and 6. The catheter body is advanced along the guidewires until the distal end of the catheter in a desired location within the vessel. Alternatively, the catheter body can be advanced along the guidewires until the distal end is adjacent to the vessel, and then the catheter and the guidewires can be advanced until the distal end is located at a desired position within the vessel. The guidewires and, optionally, the intra-catheter stiffener elements are then removed from the lumens.
• FIG. 10 shows a step of the method wherein the catheter has been subcutaneously tunneled. A subcutaneous tunnel is formed between a second location[0043]32 (exit location) and the first location6 (venotomy site). Couplers at theproximal end22 of the catheter lumens are removed, or alternatively, severed therefrom to allow the proximal end of the catheter to be pulled through thetunnel40. In one embodiment, the proximal end of the catheter is pulled through subcutaneous tunnel from the first location until it extends from the second location.
• FIG. 11 illustrates the catheter after tunneling with[0044]access ports28A and28B installed, or alternatively, replaced and ready to be coupled to a hemodialysis machine for blood purification.
• As noted above, it will be appreciated that the use of the intra-catheter stiffener elements provide sufficient stiffness so that the flexible split tips can be slid over the guidewires into the desired position with less effort and reduced likelihood of trauma. Catheter kinking is mitigated during the insertion process, thus reducing complexity of catheter insertion.[0045]
• FIG. 12 shows contents of a preferred embodiment of a[0046]kit48 providing equipment to perform the above described methods. Illustrated are twointra-catheter stiffener elements50A and50B, two guidewires52A and52B, a 6-French sheath/dilator54 and two vessel dilators of differing sizes56 and58. It will be appreciated by one skilled in the art that other arrangements are contemplated, each having at least two intra-catheter stiffener elements. For example, in one embodiment, the insertion kit has a split-tip catheter and two intra-catheter stiffener elements. The kit is suitable for insertion of either antegrade or retrograde catheter configurations according to the illustrated methods described above.
• [0047]Intra-catheter stiffener elements50A and50B are illustrated as 5-French in size and of the same length. However, intra-catheter stiffener elements50 need not be of the same size and length, but can be selected according to the size and length of the catheter to be inserted. Further, intra-catheter stiffener elements need not have a round exterior shape, but rather, can have an external shape according to the size and shape of an interior of a catheter lumen, for example, oval shaped. In a preferred embodiment, each intra-catheter stiffener element has a tapered configuration along a distal portion to aid in dilating the catheter lumen, with a releasable coupler at a proximal end such as a luer-coupler at a proximal end. Each has a hollow bore or lumen running along its length sized to slidably receive a guidewire as described above. Each preferably has stiffness sufficient to prevent the catheter from kinking or otherwise distorting during the insertion procedure. It will be appreciated that the intra-catheter stiffener elements can be in kit form as separate from, or disposed within, the catheter lumens.
• Guidewires[0048]52A and52B are illustrated as J-straight 0.038″ guidewires, however each can vary according to the application and catheter configuration. Each can have a removable sheath to accommodate handling and facilitate placement within a desired location such as a vein.
• Sheath/dilator[0049]54 is illustrated as size 6-French, however, other sizes may be used to puncture a wall of a vessel and accommodate one or more guidewires. Dilators56 and58 are illustrated as size 14-French and 16-French, respectively, and are suitable for many catheter insertion procedures. In a preferred embodiment, a size 12-French is provided in addition to or instead of one of the illustrated dilators.
• It will be appreciated, therefore, that the above methods and kits are useful for inserting hemodialysis catheters in a patient, and in general for multi-lumen split-tip catheters intended for other functions where body fluids are extracted and introduced. As such, the invention is not limited to those embodiments described above, but rather, is limited by the claims that follow.[0050]

Claims (67)

What is claimed is:

1. A method for inserting a multi-lumen catheter into a blood vessel comprising:

inserting a distal portion of each of a plurality of guidewires into a vessel at a first location;

inserting an intra-catheter stiffening element into a proximal end of each lumen of a multi-lumen catheter, the catheter having a distal portion for placement in the vessel and a proximal end for connection to a treatment device and further having a plurality of lumens;

threading a proximal end of each of the guidewires through a distal end of a respective intra-catheter stiffening element until said guidewire exits the proximal end of the catheter;

advancing the catheter into a desired location within the vessel; and

removing each of the guidewires and each of the intra-catheter stiffener elements from the lumens of the catheter.

2. The method ofclaim 1, wherein advancing the catheter into a desired location within the vessel further comprises:

advancing the catheter over the guidewires until a distal end of the catheter is adjacent to the vessel; and

further advancing the catheter and the guidewires into the vessel until the distal portion of the catheter is at the desired location within the vessel.

3. The method ofclaim 1, further comprising dilating the blood vessel subsequent to inserting a first guidewire.

4. The method ofclaim 3, further comprising dilating the blood vessel using a size 6-French sheath/dilator.

5. The method ofclaim 1, further comprising coupling a proximal end of each said intra- catheter stiffening element to a proximal end of a respective catheter lumen.

6. The method ofclaim 1, wherein the step of advancing the catheter into a desired location within the vessel comprises twisting the catheter while advancing.

7. The method ofclaim 1, wherein the catheter has a split-tip.

8. A method for inserting a multi-lumen catheter into a blood vessel comprising:

inserting a distal portion of each of a plurality of guidewires into a vessel at a first location;

forming a subcutaneous tunnel between the first location and a second location;

passing a catheter through the tunnel, the catheter having a distal portion for placement in the vessel and a proximal end for connection to a treatment device and further having a plurality of lumens;

inserting an intra-catheter stiffener element into the proximal end of each of the catheter lumens;

threading a proximal end of each of the guidewires through a distal end of a respective intra-catheter stiffener element until said guidewire exits the proximal end of the catheter;

advancing the catheter into a desired location within the vessel; and

removing each of the guidewires and each of the intra-catheter stiffener elements from the lumens of the catheter.

9. The method ofclaim 8, wherein advancing the catheter into a desired location within the vessel further comprises:

advancing the catheter over the guidewires until a distal end of the catheter is adjacent to the vessel; and

further advancing the catheter and the guidewires into the vessel until the distal portion of the catheter is at the desired location within the vessel.

10. The method ofclaim 8, further comprising dilating the blood vessel subsequent to inserting a first guidewire.

11. The method ofclaim 10, further comprising dilating the blood vessel using a size 6-French sheath/dilator.

12. The method ofclaim 8, wherein forming a subcutaneous tunnel further comprises

inserting a distal end of a pointed stylet through the skin at the second location; and

pushing the stylet toward the first location until the distal end of the stylet extends therefrom.

13. The method ofclaim 12, wherein the step of passing a catheter through the tunnel further comprises:

removeably attaching the distal end of the catheter to the proximal end of a stylet;

pulling the stylet toward the first location until the distal end of the catheter extends therefrom; and

releasing the catheter from the stylet.

14. The method ofclaim 12, wherein the stylet has a shape adapted to tunnel through subcutaneous tissue.

15. The method ofclaim 8, wherein each intra-catheter stiffener element is inserted into the catheter prior to passage of the catheter through the tunnel.

16. The method ofclaim 8, wherein each intra-catheter stiffener element is inserted into the catheter after passage of the catheter through the tunnel.

17. The method ofclaim 8, wherein the proximal end of each catheter lumen has a coupler adapted to mate with a coupler disposed at the proximal end of an intra-catheter stiffener element.

18. The method ofclaim 8, further comprising dilating the vessel to accommodate the distal portion of the catheter.

19. The method ofclaim 18, further comprising:

dilating the vessel with a first dilator; and

dilating the vessel with at least one larger further dilator.

20. The method ofclaim 19, wherein the larger further dilators are adapted to dilate the vessel to slidably receive the distal portion of the catheter having each catheter lumen stiffened by a respective intra-catheter stiffener element disposed therein.

21. The method ofclaim 19, wherein the first dilator is a size 12-French dilator.

22. The method ofclaim 19, wherein the further dilators are any of the group consisting of a size 14-French and a 16-French dilator.

23. The method ofclaim 8, wherein the step of advancing the catheter further comprises looping the catheter between the first location and the vessel so as to facilitate advancing the distal portion of the catheter into the vessel.

24. The method ofclaim 23, further comprising pulling the proximal end of the catheter to remove the loop subsequent to advancing the distal portion of the catheter into the vessel.

25. The method ofclaim 8, wherein the step of advancing the catheter further comprises twisting the catheter to facilitate advancement of the distal portion of the catheter to the desired location within the vessel.

26. The method ofclaim 8, further comprising coupling the catheter to a hemodialysis treatment device.

27. The method ofclaim 26, wherein the catheter is a dual-lumen antegrade tunneled hemodialysis catheter.

28. A method for inserting a multi-lumen catheter into a blood vessel comprising:

inserting a distal portion of each of a plurality of guidewires into a vessel at a first location;

placing intra-catheter stiffener elements into each lumen of a multi-lumen catheter;

threading a proximal end of each of the guidewires through a distal end of a respective intra-catheter stiffener element disposed within the catheter lumen until said guidewire exits a proximal end of the intra-catheter stiffener element;

advancing the catheter into a desired location within the vessel;

removing each of the guidewires and each of the intra-catheter stiffener elements from the lumens of the catheter;

forming a subcutaneous tunnel between the first location and a second location;

passing the catheter through the tunnel; and

connecting an adapter to a proximal end of each of the catheter lumens, the adapter configured to connect to a treatment device.

29. The method ofclaim 28, wherein advancing the catheter into a desired location within the vessel comprises

advancing the catheter over the guidewires until the distal end of the catheter is adjacent to the vessel; and

further advancing the catheter and the guidewires into the vessel until the distal end of the catheter is at the desired location within the vessel.

30. The method ofclaim 28, further comprising dilating the blood vessel subsequent to inserting a first guidewire.

31. The method ofclaim 30, further comprising dilating the blood vessel using a size 6-French sheath/dilator.

32. The method ofclaim 28, wherein forming a subcutaneous tunnel further comprises:

inserting a distal end of a pointed stylet through the skin at the first location; and

pushing the stylet toward the second location until the distal end of the stylet extends therefrom.

33. The method ofclaim 28, wherein the step of passing a catheter through the tunnel further comprises:

removeably attaching the proximal end of the catheter to the proximal end of a stylet;

pulling the stylet back toward the second location until the proximal end of the catheter extends therefrom; and

releasing the catheter from the stylet.

34. The method ofclaim 33, wherein the distal end of the stylet has a sharpened point adapted to tunnel through subcutaneous tissue.

35. The method ofclaim 33, wherein the proximal end of the stylet has a feature adapted to removably affix the proximal end of the catheter.

36. The method ofclaim 28, wherein each intra-catheter stiffener element releasably attaches to the proximal end of its respective catheter lumen.

37. The method ofclaim 36, wherein each intra-catheter stiffener element stiffens its respective catheter lumen.

38. The method ofclaim 36, wherein the proximal end of each catheter lumen has a removable coupler adapted to mate with a coupler disposed at the proximal end of an intra-catheter stiffener element.

39. The method ofclaim 28, further comprising dilating the vessel to accommodate the distal portion of the catheter.

40. The method ofclaim 39, further comprising:

dilating the vessel with a first dilator; and

dilating the vessel with at least one larger further dilator.

41. The method ofclaim 40, wherein the larger further dilators are adapted to dilate the vessel to slidably receive the distal portion of the catheter having each catheter lumen stiffened by a respective intra-catheter stiffener element disposed therein.

42. The method ofclaim 40, wherein the first dilator is a size 12-French dilator.

43. The method ofclaim 40, wherein the further dilators are any of the group consisting of a size 14-French and 16-French dilator.

44. The method ofclaim 28, further comprising coupling the catheter to a hemodialysis device.

45. The method ofclaim 44, wherein the catheter is a dual-lumen retrograde tunneled hemodialysis catheter.

46. A kit for applying a multi-lumen catheter into a blood vessel comprising:

a plurality of guidewires, each adapted to have a distal portion inserted in a blood vessel; and

a plurality of intra-catheter stiffener elements, each of the intra-catheter stiffener elements sized to be slidably disposed within a lumen of a multi-lumen catheter and each having a lumen sized to slide over a guidewire.

47. The kit ofclaim 46, further comprising a vessel dilator adapted to be advanced into the blood vessel over a first inserted guidewire, the vessel dilator sized to dilate the blood vessel to accommodate insertion of further ones of the guidewires.

48. The kit ofclaim 47, wherein the vessel dilator is a size 6-French sheath/dilator.

49. The kit ofclaim 49, further comprising at least one further vessel dilator sized to dilate a blood vessel to accommodate insertion of a catheter.

50. The kit ofclaim 49, wherein the further vessel dilators are any size of the group consisting of size 12-French, 14-French and 16-French.

51. The kit ofclaim 46, wherein the intra-catheter stiffener elements have a tapered distal portion.

52. The kit ofclaim 46, wherein each intra-catheter stiffener element has a coupler disposed at a proximal end adapted to releasably couple to a coupler disposed at the proximal end of a respective catheter lumen.

53. The kit ofclaim 52, wherein the intra-catheter stiffener elements are releasably coupled to a proximal end of the catheter lumens.

54. The kit ofclaim 52, wherein the intra-catheter stiffener elements have a predefined length corresponding to a length of a catheter selected for use in a particular application.

55. The kit ofclaim 54, wherein the catheter is a hemodialysis catheter.

56. The kit ofclaim 46, further comprising a multi-lumen catheter.

57. The kit ofclaim 56, wherein the intra-catheter stiffener elements are pre-disposed within the lumens of the catheter.

58. A kit for applying a multi-lumen catheter into a blood vessel comprising:

a multi-lumen catheter comprising a distal portion to be placed in a blood vessel and a coupler disposed at a proximal end of each catheter lumen; and

a plurality of intra-catheter stiffener elements, each of the intra-catheter stiffener elements sized to be slidably disposed within a lumen of the catheter and each having a lumen sized to slide over a guidewire, the intra-catheter stiffener elements having a tapered distal portion and a proximal end having a coupler adapted to mate with the coupler at the proximal end of a catheter lumen.

59. The kit ofclaim 58, further comprising a vessel dilator adapted to be advanced into the blood vessel over a first inserted guidewire, the vessel dilator sized to dilate the blood vessel to accommodate insertion of further ones of the guidewires.

60. The kit ofclaim 59, wherein the vessel dilator is a size 6-French sheath/dilator.

61. The kit ofclaim 60, further comprising at least one further vessel dilator sized to dilate a blood vessel to accommodate insertion of a catheter.

62. The kit ofclaim 61, wherein the further vessel dilators are any size of the group consisting of 12-French, 14-French and 16-French.

63. The kit ofclaim 58, wherein the intra-catheter stiffener elements have a predefined length corresponding to a length of the catheter selected.

64. The kit ofclaim 58, wherein the intra-catheter stiffener elements have an exterior shape sized to be received by an interior shape of the catheter lumens.

65. The kit ofclaim 58, wherein the intra-catheter stiffener elements are pre-disposed within the lumens of the catheter.

66. The kit ofclaim 58, wherein the catheter is a hemodialysis catheter.

67. The kit ofclaim 58, wherein the distal portion of the catheter has a split-tip.

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