WO2002013899A1

WO2002013899A1 - Multi-sided catheters

Info

Publication number: WO2002013899A1
Application number: PCT/US2001/025619
Authority: WO
Inventors: John G. Evans; Raymond Lee Kester, Jr.
Original assignee: C.R. Bard, Inc.
Priority date: 2000-08-17
Filing date: 2001-08-16
Publication date: 2002-02-21
Also published as: AU2001284964A1

Abstract

An improved catheter having an outer wall with multiple sides. The catheter can either be symmetrical having a cross-sectional shape such as a square, rectangle, pentagon or hexagon or be asymmetrical. The catheter can contain a single lumen or have multiple lumen, with various shapes possible for each lumen. The outer and inner walls of the catheter are varied in thickness in relation to the anticipated pressures. Thus, lumen that will be used for pressures exceeding blood pressure will have thinner walls and will depend on the pressure difference between the lumen and the blood vessel to hold the lumen open. Conversely, lumen that will be used for pressures lower than that of circulating blood will have thicker walls to resist collapse. The variable wall thickness allows for optimization of material utilized in the catheter while the multi-sided configuration imparts to the catheter a structural integrity component that assists in avoiding wall collapse and makes the catheter highly kink resistant.

Description

MULTI-SIDED CATHETERS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to catheters, and more particularly to a catheter having a multi-sided cross-sectional shape and variable or modulated wall thickness.

2. Description of Related Art

In a progression of catheters ranging from single lumen catheters to multiple lumen catheters, the basic outside cross-sectional shape has remained circular. This can be attributed to many factors, including ease of manufacture, reduced trauma to the patient, and optimal flow characteristics. Particularly in a single lumen catheter, a circular cross section provides minimized frictional resistance to fluid flow due to the absence of restrictive areas in the lumen and achieves laminar flow under high flow pressures. Multiple lumen catheters, which are very useful in treatments such as hemodialysis due to the need for simultaneous infusion and withdrawal of fluids at high flow rates, also benefit from many of these stated advantages with respect to a circular cross-sectional shape.

Various designs for multiple lumen catheters have been created by dividing the circular outer cross-section of the catheter with one or more septa, creating two or more lumen. Examples of multiple lumen designs include a Circle-C lumen design and a Double-D lumen design. In the Circle-C lumen design, there exists a main lumen and a secondary lumen, which together form a circular shape. However, the secondary lumen is much smaller than the main lumen, which is C-shaped. The Double-D lumen design, on the other hand, has two equally sized lumen, created by bisecting the circular cross-section of a single lumen catheter with a septum. This design is the most commonly used and well- known in the hemodialysis industry.

Improvements to multiple lumen catheters have been addressed in a number of earlier patents. For example, catheter kinking was addressed by Martin et al. in U.S. Patent No. 5,156,592, wherein the catheter, circular in cross- section, is pre-curved to conform to the shape of the incision typically formed in the body of the patient. However, because the cross-section of the catheter in Martin et al. is circular, there still exists the possibility of kinking and wall collapse when the device is implanted in the patient. Hattler et al. (U.S. Patent No. 4,406,656) sought to solve the problem of collapsing walls by providing walls that were initially collapsed. These collapsible walls should expand under the pressure of fluid flow therethrough, with the central lumen providing structural support for the catheter. While this device potentially eliminates the problem of kinking, the collapsibility of the walls may lead to other problems such as clotting when there is prolonged cessation of flow through a given lumen, as well as a potential for tearing because of the lack of wall thickness. In U.S. Patent No. 5,556,390 to Hicks, these same problems were addressed in a different manner by providing a catheter with one or more lumen which are oval, eliptical or oblong shaped. These luminal shapes allow the thickness of the outer wall and the septum to be much greater than in the prior art to avoid wall collapse. However, due to the circular cross-section of the outer wall of the catheter, wall collapse is still possible in designs involving more than two lumen, and the likelihood of kinking still remains. Thus, there exists a need to provide a multi-lumen catheter in which the outer and inner wall thickness can be varied in relation to anticipated pressures. In addition, there exists a need to provide a multi-lumen catheter which will be highly kink resistant as well as resistant to wall collapse.

SUMMARY OF THE INVENTION Accordingly, the present invention provides an improved catheter having an outer wall with multiple sides. The catheter can either be symmetrical having a cross-sectional shape such as a square, rectangle, pentagon or hexagon or be asymmetrical. The shapes impart a structural integrity component that assists in avoiding wall collapse and makes the catheter highly kink resistant. Whether the catheter has a single or multiple lumen configuration, the shape of each lumen is widely variable. For instance, in a triple lumen catheter with a pentagonal cross- section, a primary lumen can be subdivided by a septum or septa into sublumen of either triangular or rhomboidal shape. There are numerous additional possibilities for the shapes of the lumen (sublumen), some of which are specifically illustrated in the drawings.

The outer and inner walls of the catheter can be varied in thickness in relation to the anticipated pressures. Thus, lumen that will be used for pressures exceeding blood pressure will have thinner walls and will depend on the pressure difference between the lumen and the blood vessel to hold the lumen open. Conversely, lumen that will be used for pressures lower than that of circulating blood will have thicker walls to resist collapse. This variable wall thickness allows for optimization of material utilized in the catheter and also imparts to the catheter a resistance to wall collapse.

These and other features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the preferred embodiments of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a cross-sectional view of one embodiment of a four-sided catheter of the present invention with an essentially square lumen.

Fig. IB is a cross-sectional view of another embodiment of a four-sided catheter of the present invention with dual rectangular lumen.

Fig. 1C is a cross-sectional view of another embodiment of a four-sided catheter of the present invention with dual rectangular lumen. Fig. 2A is a cross-sectional view of one embodiment of a four-sided catheter of the present invention with dual triangular lumen.

Fig. 2B is a cross-sectional view of another embodiment of a four-sided catheter of the present invention with dual triangular lumen.

Fig. 2C is a cross-sectional view of a third embodiment of a four-sided catheter of the present invention with dual triangular lumen. Fig. 2D is a cross-sectional view of a fourth embodiment of a four-sided catheter of the present invention with dual triangular lumen.

Fig. 3A is a cross-sectional view of a five-sided catheter of the present invention showing a dual lumen configuration. Fig. 3B is a cross-sectional view of a five-sided catheter of the present invention showing a triple lumen configuration.

Fig. 3C is a cross-sectional view of another embodiment of a five-sided catheter of the present invention with a triple lumen configuration.

Fig. 4 A is a cross-sectional view of a six-sided catheter of the present invention showing a dual lumen configuration.

Fig. 4B is a cross-sectional view of a six-sided catheter of the present invention showing a triple lumen configuration.

Fig. 4C is a cross-sectional view of another embodiment of a six-sided catheter of the present invention showing a dual lumen configuration. Fig. 4D is a cross-sectional view of yet another embodiment of a six-sided catheter of the present invention showing a dual lumen configuration.

Fig. 5 A is a cross-sectional view of a seven-sided assymetrical catheter of the present invention showing a dual lumen configuration.

Fig. 5B is a cross-sectional view of a seven-sided assymetrical catheter of the present invention showing a triple lumen configuration.

Fig. 6 is a cross-sectional view of a five-sided assymetrical catheter of the present invention showing a dual lumen configuration.

DETAILED DESCRIPTION OF THE INVENTION The present invention satisfies the need for an improved catheter that exhibits resistance to kinking and wall collapse. In the detailed description that follows, it should be appreciated that like reference numerals are used to describe like elements illustrated in one or more of the figures.

Referring to Fig. 1 A, a catheter 10 is shown with an outer wall 12 having a square-shape in cross-section. In this first embodiment, a single, large square- shaped primary lumen 14 passes through the middle of the catheter 10, while two smaller circular lumen 16 run adjacent to two corners of the catheter 10. Conceptually a catheter is an outer wall surrounding a primary lumen. This lumen may be subdivided by a septum or septa into one or more sublumen. For convenience the sublumen are generally referred to as "lumen" herein. It should be appreciated in this embodiment as well as the examples given below that any number of smaller circular lumen can accompany the larger multi-sided lumen(s) in various locations throughout the catheter cross-section. These smaller lumen can be used for fluid flow, but are generally designated for guidewires to introduce the catheter into the bodily vessel. Fig. IB illustrates a catheter 20, also possessing a square-shaped outer wall 12. This embodiment has a dual lumen (sublumen) configuration including a first lumen 24 and a second lumen 26. In this embodiment, the two lumen 24 and 26 are identical in size and shape, but either could vary in size depending on the particular application. Moreover, unique to this invention, the walls of the catheter can be varied in thickness. Thus, in Fig. IB, if first lumen 24 was designated for pressures lower than that of circulating blood and second lumen 26 was designated for pressures exceeding blood pressure, a wall thickness 22 would be greater than a wall thickness 28. Finally, Fig. 1C illustrates a catheter 30 with a third embodiment having the square-shaped outer wall 12 with rectangular lumen. In this embodiment, a guidewire lumen 38 runs through the center of the catheter

30 and has a first lumen 34 and a second lumen 36 on either side. As with the embodiment shown in Fig. IB, the wall thickness of the catheter 30 is variable depending on the pressure flow through the lumen 34 and 36.

Figs. 2A-2D illustrate further embodiments having the square-shaped outer wall 12. However, in these embodiments, the primary lumen are triangular.

In Fig. 2A, a catheter 40 is shown with a first triangular lumen 44 and a second triangular lumen 46. As with the catheters 20 and 30 in Figs. IB and 1C, respectively, the wall thickness of the catheter 40 is variable depending on the pressure designated for each lumen. Therefore, if the first and second lumen 44 and 46 are to be used for different purposes, requiring pressures above and below the blood circulation pressure, the walls 42 and 48, which are adjacent to the first and second lumen 44 and 46, would be of different thickness. Fig. 2B shows a catheter 50 that differs slightly from the catheter 40 in that a guidewire lumen 58 is disposed in one of the corners of the catheter 50, adjacent to both the first lumen 54 and the second lumen 56. Fig. 2C illustrates a catheter 60 that has triangular lumen 64 and 66 of a slightly different configuration, in addition to two guidewire lumen 68. Finally, Fig. 2D illustrates a catheter 70 that has a guidewire lumen 78 running through the center of the catheter 70 with first and second lumen 74 and 76 on either side.

Figs. 3A-3C illustrate a five-sided embodiment of the present invention. The pentagonal catheters have an outer wall 102 with five distinct sides. In Fig.

3A, catheter 100 has two similarly shaped lumen, first lumen 104 and second lumen 106. These lumen eachhave four sides and conform to the outer wall 102 of the catheter 100. As with the outer walls shown in the four-sided configurations in Figs 1 and 2, the walls of the pentagonal catheters shown in Fig. 3 have a variable thickness depending on the intended fluid pressure of the lumen to which they are adjacent. Fig. 3B shows a catheter 110 that contains a first, second and third triangular lumen 114, 116 and 118 respectively. Fig. 3C shows a catheter 120 that also contains three lumen, but the first lumen 124 and the third lumen 128 are rhomboidal in shape, having four sides, while second lumen 126 is pentagonal, possessing five sides.

In a six-sided embodiment of the present invention, Figs. 4A-4D illustrate various preferred configurations. All of the configurations of this embodiment have an outer wall 202 in the form of a hexagon with six distinct sides. As with the other embodiments above, these sides are shown with fairly sharp corners to emphasize the shape of each catheter. In actual practice, however, the transitions between facets may be somewhat more rounded. In Fig. 4A, a catheter 200 is shown with a first lumen 204 and a second lumen 206. While these lumen are shown to be similar in shape, following the outline of the outer wall 202, other possible configurations include two lumen that have a differing number of sides or that are circular. Fig. 4B illustrates a catheter 210, containing three lumen, a first lumen 214, a second lumen 216 and a third lumen 218, each having five sides. Fig. 4C, on the other hand, shows a catheter 220 with three lumen, each having four sides. Finally, in Fig. 4D, a hexagonal catheter 230 with the outer wall 202 is shown with two primary lumen, a first lumen 234 and a second lumen 236. These two lumen 234 and 236 are configured to follow the outline of the outer wall 202 as well as to permit the passage of a guidewire lumen 238 through the center of the catheter 230.

Figs. 5A, 5B and 6 illustrate embodiments of the present invention that have assymetrical outer walls. Figs. 5A and 5B are seven-sided configurations, while Fig. 6 is a 5-sided configuration. Fig. 5 A illustrates a catheter 300 in cross- section having a first lumen 304 in the form of a pentagon, mirroring the outer wall portion to which it is adjacent, and a second lumen 306 in the shape of a rhombus, also mirroring the outer wall portion to which it is adjacent. While the two lumen are shown in Fig. 5 paralleling the outer wall 302, it should be appreciated that other possibilities exist in the spirit of this invention. For example, one or both of the lumen could be circular or triangular, etc. Fig. 5B shows a multi-sided catheter 310, also with outer wall 302, but instead having three lumen 314, 316 and 318. Again, while the lumen in this example are shown to parallel the walls to which they are adjacent, several shapes for the lumen are possible. Finally, Fig. 6 illustrates another assymetrical embodiment of the present invention, multi-sided catheter 400 with outer wall 402 having five sides with lumen 404 and 406.

Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the present invention. For example, while catheters have been illustrated with two or three lumen, it should be apparent that the inventive concepts herein would be equally applicable to any number of lumen of various shapes and sizes. Moreover, the words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself. The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result.

Claims

CLAIMS We Claim:

1. A multi-lumen catheter, comprising: an outer catheter wall having more than three distinct sides; a lumen defined by the outer catheter wall; and a septum partitioning the lumen into at least two sublumen.

2. The multi-lumen catheter of Claim 1, wherein the septum defines a first sublumen and a second sublumen, wherein the outer catheter wall adjacent to the first sublumen has a wall thickness greater than that of the outer wall adjacent to the second sublumen.

3. The multi-lumen catheter of Claim 2, further comprising at least one guidewire lumen.

4. The multi-lumen catheter of Claim 2, wherein the first and second sublumen have substantially the same transverse cross-sections.

5. The multi-lumen catheter of Claim 1, wherein the septum defines at least three sublumen, wherein the sublumen have transverse cross-sections that contain an equal number of distinct sides.

6. A multi-lumen catheter, comprising: an outer catheter wall having at least two substantially flat sides; a lumen defined by the outer catheter wall; and a septum partitioning the lumen into at least two sublumen.

7. A multi-lumen catheter, comprising: an outer catheter wall having a symmetrical cross-sectional shape, wherein the shape is selected from the group consisting of a square, a pentagon, a hexagon, a heptagon or an octagon; a lumen defined by the outer catheter wall; and a septum partitioning the lumen into at least two sublumen.

8. A multi-lumen catheter, comprising: an outer catheter wall having an asymmetrical cross-sectional shape containing at least two substantially flat sides; a lumen defined by the outer catheter wall; and a septum partitioning the lumen into at least two sublumen.

9. A multi-lumen catheter, comprising: an outer catheter wall having a transverse cross-section that does not contain an arcuate portion; a lumen defined by the outer catheter wall; and a septum partitioning the lumen into at least two sublumen.