WO2010078102A1

WO2010078102A1 - High pressure infusion catheter

Info

Publication number: WO2010078102A1
Application number: PCT/US2009/068935
Authority: WO
Inventors: David Christian Lentz
Original assignee: Cook Incorporated
Priority date: 2008-12-29
Filing date: 2009-12-21
Publication date: 2010-07-08

Abstract

A catheter (10) having an outer tubular layer (42) defining a lumen (13) and a thin-walled liner (11) on an inner surface of an outer tubular layer is disclosed. In the presently preferred embodiment, the material of the liner is PTFE which has a thickness of ≤ 0.0015 inches. The outer tubular layer is composed of a nylon, polyurethane, or PEBAX material. The flex modulus of this material is under 60,000 psi so that the catheter retains some flexibility. Although the liner by itself is fairly rigid and kinkable, the PTFE liner provides excellent strength in preventing ruptures. The traits change, however, when the outer tubular layer is applied. The combination of the two materials results in a flexible shaft with excellent flow rate capacity.

Description

HIGH PRESSURE INFUSION CATHETER

FIELD OF THE INVENTION

[0001] The present invention generally relates to a catheter, and in particular, to an infusion catheter with a high flow rate capacity.

BACKGROUND OF THE INVENTION

[0002] A peripherally inserted central catheter (PICC) is a form of intravenous access that can be used for a prolonged period of time, e.g. for extended chemotherapy regimens, long duration antibiotic therapy or total parenteral nutrition. Accordingly, peripherally inserted central catheters have several requirements that are necessitated by these and related procedures.

[0003] First, they need to have high flow rates to deliver large quantities of fluid media to the blood stream. In particular, the catheters need to be able to handle large volumes of therapeutic agents. However, high flow rates may generate relatively high pressure and cause the formation of aneurisms, which may result in a potential rupture to the veins.

[0004] Second, these catheters need to be fairly flexible. This is because increased flexibility of catheters may reduce potential trauma to the veins caused by catheters remaining in the body for several weeks. In addition, increased flexibility may also reduce the potential kinking of catheters. Kinking often occurs as the catheter is introduced and advanced into the patient, particularly when advanced along a tortuous pathway or past luminal strictures.

[0005] Therefore, a catheter is needed that may provide sufficient strength to withstand the high pressure generated by high flow rates as well as high degree of flexibility to reduce potential trauma and kinking.

SUMMARY OF THE INVENTION

[0006] The present invention is directed to a catheter having an outer tubular layer defining a lumen and a thin- walled liner disposed on the inner surface of the outer tubular layer.

[0007] In one embodiment of the invention, the outer tubular layer is composed of a nylon, polyurethane, or polyether block amide (PEBAX) material. The flex modulus of this material is under 60,000 psi, which allows the catheter to retain some degree of flexibility.

The thin- walled liner disposed on the inner surface of the outer tubular layer comprises polytetrafluoroethylene (PTFE) having a thickness of <0.0015 inches. The thin-walled PTFE liner provides high degree of strength that is sufficient to withstand the relatively high pressure that is typically generated by high flow rates and is therefore resistant to rupturing. However, the liner material by itself is fairly rigid and kinkable. When the outer tubular layer is applied there over, these traits of rigidity and kinking are modified. The combination of the two materials results in a flexible shaft with excellent flow rate capacity. [0008] In another embodiment of the invention, the liner on inner surface of the outer tubular layer of the catheter includes a thin-walled polyolefin or PEBAX heat shrink material. Due to the greater strength of this material, the burst pressure of the device increases, while minimally affecting the flexibility.

[0009] In a third embodiment of the invention, the catheter comprises multiple lumens. Each lumen is PTFE-lined. These lumens may be round or oval in shape, which minimizes their profiles and maximizes their flow rates. Ovaling of lumens can be accomplished by inserting undersized mandrels into the liners prior to applying the outer tubular layer of polymer or heat shrink material. The compressive forces applied during processing will naturally oval out the liner. The PTFE liner may also comprise a heat shrinkable form that can be shrunk over on an oval shaped mandrel, over which the outer tubular layer material can then be applied.

[0010] In a fourth embodiment of the invention, a nylon, polyurethane or PEBAX material is sandwiched between the outer heat shrink material and the thin-walled liner. The flex modulus is varied along the length of the shaft to provide variable flexibility along the length thereof. This can also fill in the voids that are present with the multilumen variants. The material may also be selectively filled with radio-opaque material for fluoro imaging. [0011] These and other advantages, as well as the invention itself, will become apparent in the details of construction and operation as more fully described below. Moreover, it should be appreciated that several aspects of the invention can be used with other types of catheters or elongate medical devices utilized for delivering a fluid or therapeutic agent to a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of the first embodiment of the invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view of the third embodiment of the invention; and FIG. 4 is a cross-sectional view of the fourth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following detailed description. However, the embodiments of this invention as described below are by way of example only, and the invention is not limited to the embodiments illustrated in the drawings. It should also be understood that the drawings are not to scale and in certain instances details have been omitted, which are not necessary for an understanding of the present invention, such as conventional details of fabrication and assembly.

[0014] FIGS. 1-2 illustrate an exemplary embodiment. The catheter 10 has an outer tubular layer 12 which forms a lumen 13. The thin-walled liner 11 is disposed on the inner surface of the outer tubular layer 12. The material of the thin- walled liner 11 on the inner surface of the outer tubular layer 12 is PTFE, which has a thickness of <0.0015 inches. The outer tubular layer 12 is composed of a nylon, polyurethane, or PEBAX material. The flex modulus of the outer material is under 60,000 psi so that the catheter 10 retains some overall flexibility. The liner 11 by itself is fairly rigid and tends to kink. Nevertheless, it provides excellent strength and can accommodate the relatively high pressure that is typically generated by high flow rates, which prevents rupturing of the catheter 10. When the outer tubular layer 12 is applied to and disposed over the inner layer 11, however, the inner layer's traits of rigidity and tendency to kink are modified. The combination of the two materials results in a flexible shaft with excellent flow rate capacity.

[0015] In a second embodiment, the liner 11 on the inner surface of the outer tubular layer 12 of the catheter 10 includes the use of thin- walled polyolefin or PEBAX heat shrink material. This increases the burst pressure of the device due to the higher relative strength of this material while minimally affecting the flexibility.

[0016] FIG. 3 illustrates a third embodiment. The catheter 10 forms multiple lumens 13. Each lumen 13 is PTFE-lined. These lumens 13 are preferably rounded or oval in shape, which minimizes their profiles and maximizes their flow rates. However, other cross- sectional shapes can be employed depending on the size, number and arrangement of the lumens 13. In the particular embodiment illustrated, the lumens 13 each have a rounded "D"- shape. Rounding or ovaling of the lumens 13 can be accomplished by inserting undersized mandrels into the liners 11 prior to applying the outer tubular layer 12 of polymer or heat shrink material. The compressive forces applied during processing will naturally oval out the liner 11. The PTFE liner 11 may also comprise a heat shrinkable form that can be shrunk on an ovaled mandrel, over which the outer tubular layer 12 material can then be applied. [0017] FIG. 4 illustrates a fourth embodiment. A nylon, polyurethane or PEBAX material 12 is sandwiched between the outer heat shrink material 14 and the thin- walled liner 11. The flex modulus of the heat shrink material 14 may be varied along the length of the shaft to provide a variable flexibility to the shaft. For example, in some embodiments the distal portion of the shaft may be made more flexible than the proximal portion of the shaft to provide a shaft that is both flexible and pushable. The heat shrinkable material 14 can also fill in any voids that may be present within the middle layer 12 of the multilumen variants. Selective portions of the heat shrink material 14 may also be filled with a radio-opaque material for fluoro imaging.

[0018] While there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention. It is to be understood that the invention can be carried out by specifically different apparatus and methods of use, and that various modifications, both as to the apparatus details and use thereof, can be accomplished without departing from the scope of the invention itself.

Claims

CLAIMS:

1. A medical catheter comprising an elongate shaft, the shaft comprising: an outer tubular layer defining a lumen; and a thin- walled liner disposed on an inner surface of the outer tubular layer, the liner comprising a PTFE material and having a thickness of equal to or less than about 0.0015 inches.

2. The catheter of Claim 1, wherein the liner material is selected from the group consisting of polyolefin and PEBAX.

3. The catheter of Claim 2, wherein the outer tubular layer is selected from the group consisting of nylon, polyurethane and PEBAX.

4. The catheter of Claim 3, wherein the outer tubular layer material has a flex modulus of less than 60,000 psi.

5. The catheter according to any of the preceding claims, wherein the lumen comprises a plurality of sub-lumens separated by the PTFE liner material.

6. The catheter of Claim 5, wherein the sub-lumens each have a rounded or oval cross-sectional shape.

7. The catheter according to any of the preceding layers, wherein a heat shrinkable material is disposed over an outer surface of the outer tubular layer.