Symmetrical filling of acute central venous catheters

Abstract

The system includes a catheter (10) and one or more fillers or plugs (400, 500, 600, 702, 704) configured to block a lumen (14) of the catheter. The catheter may include an elongated tube (12) having a distal end (12B) and defining multiple lumens (14). A distal tip structure (170) may be located adjacent the distal end. The plug is configured to be positioned within a first portion of a first lumen of the multiple lumens proximal to the distal tip. The plug may include an elliptical cross-sectional shape and may be formed from a biocompatible polymeric material, such as silicone, nylon, polyurethane, polyethylene terephthalate, latex, plastic, thermoset, or thermoplastic elastomer. The elliptical cross-sectional shape may have first and second apexes, and the first plug is configured such that either of the apexes can be positioned adjacent an upper side of the first lumen without causing distension of the lumen wall.

Description

[Background technology]

[0001] During catheter manufacturing, a catheter tipping or end-shaping process is performed to shape the ends of the thermoplastic tubing, which can be performed using a heat-conductive mold. Prior to tipping, the distal portion of one or more lumens (e.g., the proximal and intermediate lumens) must be occluded to prevent bacterial growth or thrombus formation in the space between the lumen exit and the tip of the catheter. This is typically accomplished with a monofilament inserted into the lumen. In some catheters, the proximal and intermediate lumens of the catheter shaft have a unique kidney-like cross-sectional shape, and the geometry of the filler material must attempt to fill most, if not all, of the lumen area. Summary of the Invention [Problem to be solved by the invention]

[0002] Currently implemented monofilaments include monofilaments with geometries that attempt to replicate the shape of a lumen. For example, current monofilaments have a substantially kidney-shaped cross-sectional shape. While this geometry would theoretically effectively fill such a lumen, in practice, this geometry exhibits a number of drawbacks. First, the complexity of the monofilament's geometry prevents monofilament extrusion vendors from accurately replicating the geometry of the kidney-shaped lumen, which impacts the effectiveness of the plug's ability to fill the lumen. Second, because the kidney-shaped cross-sectional shape is not symmetrical along any axis, operators often load the monofilament into the lumen in the wrong direction during manufacturing, which can result in one or more bulges in the catheter shaft or lumen wall.

[0003] Therefore, what is needed is a plug with an improved geometry that does not suffer from the drawbacks of current filler materials by simplifying the shape of the extrusion die, which improves the extrusion accuracy of the monofilament bender and avoids displacement of the plug within the lumen during manufacturing. [Means for solving the problem]

[0004] Briefly summarized, embodiments of the present invention are directed to a system including a catheter and a first plug of a filler material. The catheter includes an elongate tube having a distal end and defining multiple lumens, and a distal tip structure located adjacent the distal end. The first plug is configured to be disposed within a first portion of a first lumen of the multiple lumens proximal to the distal tip and is defined as having an elliptical cross-sectional shape.

[0005] In some embodiments, a second plug of filler material is disposed within a second portion of one of the lumens, the second plug being defined as having an elliptical cross-sectional shape. In some cases, the first plug and the second plug are disposed within different lumens. In some examples, the first plug is formed from a biocompatible polymeric material including one or more of silicone, nylon, polyurethane, polyethylene terephthalate, latex, plastic, thermoset, or thermoplastic elastomer. In some cases, the first plug is formed from a radiopaque material.

[0006] The first plug includes a cross section having a first line of symmetry, the length of which is within the range of 0.0889 to 0.127 cm (0.035 to 0.050 inches). In some specific embodiments, the length of the first line of symmetry is 0.10414 ± 0.00508 cm (0.041 ± 0.002 inches). Additionally, the first plug includes a cross section having a second line of symmetry, the length of which is within the range of 0.04445 to 0.0889 cm (0.0175 to 0.035 inches). In some specific embodiments, the length of the second line of symmetry is 0.0635 ± 0.00381 cm (0.0250 ± 0.0015 inches).

[0007] The elliptical cross-sectional shape of the first plug includes a first apex and a second apex, and the first plug is configured such that either the first apex or the second apex can be positioned near the upper side of the first lumen without causing distension of the wall of the lumen.

[0008] In some embodiments, the first portion of the first lumen is located within the distal section of the catheter, the first portion of the first lumen is located within the intermediate section of the catheter, or the first portion of the first lumen is located within the proximal section of the catheter. In some embodiments, the multiple lumens include a first lumen and a second lumen arranged in a generally double-D shape, and the corners of each lumen are rounded. In some examples, the multiple lumens include a first lumen, a second lumen, a third lumen, and a fourth lumen, and each lumen is separated from another lumen by at least one partition.

[0009] In some embodiments, the multiple lumens include a first lumen, a second lumen, a third lumen, and a fourth lumen, wherein at least two of the multiple lumens are bisected by a plane including one of the minor axis or the major axis of the catheter, and at least one of the multiple lumens is capable of power injection. In some cases, a proximal portion of the elongate tube defines a circular cross-section and a distal portion of the elongate tube defines an elliptical cross-section. In some embodiments, the proximal portion of the elongate tube defines an elliptical cross-section and a distal portion of the elongate tube defines a circular cross-section. In some cases, the multiple lumens include a cross-sectional profile that is generally triangular or kidney-shaped.

[0010] In some embodiments, the catheter is an acute central venous catheter. These and other features of embodiments of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the embodiments of the invention as set forth hereinafter.

[0011] A more particular description of the present disclosure will be provided by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. It should be understood that these drawings depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention. Exemplary embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1 is a perspective view of a catheter assembly configured in accordance with one embodiment. [Figure 1B] FIG. 1 is a cross-sectional view of a catheter assembly constructed in accordance with one embodiment. [Figure 2] 1 illustrates a cross-sectional view of a filler material according to one embodiment. [Figure 3] 3 is a cross-sectional view of a catheter tube including the filler material of FIG. 2, according to one embodiment. [Figure 4] FIG. 1 is a cross-sectional view of a filler material according to one embodiment. [Figure 5] FIG. 5 is a cross-sectional view of a catheter tube including the filler material of FIG. 4, according to one embodiment. [Figure 6] FIG. 1 is a cross-sectional view of a catheter tube including a filler material, according to one embodiment. [Figure 7] FIG. 1 is a cross-sectional view of a catheter tube including multiple filler materials, according to one embodiment. [Figure 8] FIG. 1 is a cross-sectional view of a catheter tube including multiple fillers with different cross-sectional shapes, according to one embodiment. [Figure 9] FIG. 1 is a cross-sectional view of a catheter tube including multiple filler materials of the same cross-sectional shape in various sizes, according to one embodiment. [Figure 10] FIG. 1 is a cross-sectional view of a catheter tube including multiple filler materials, according to one embodiment. [Figure 11] FIG. 11 is a perspective view illustrating the insertion and placement of the catheter tube of FIG. 10 into an introducer, according to one embodiment. [Figure 12] 11 is a cross-sectional view illustrating the insertion and placement of the catheter tube of FIG. 10 into an introducer, according to one embodiment. [Figure 13A] FIG. 1 is a side view of a catheter assembly, according to one embodiment. [Figure 13B] FIG. 1 is a top view of a catheter assembly, according to one embodiment. [Figure 14A] FIG. 13C is a cross-sectional view of the catheter assembly of FIG. 13B including a filler material. [Figure 14B] FIG. 13C is a cross-sectional view of the catheter assembly of FIG. 13B including a filler material. [Figure 15] 1 illustrates an exemplary method of coupling a distal tip structure to a catheter body, according to one implementation. DETAILED DESCRIPTION OF THE INVENTION

[0013] Before some specific embodiments are disclosed in more detail, it should be understood that the specific embodiments disclosed herein do not limit the scope of the concepts provided herein, and that the specific embodiments disclosed herein can have features that are easily separated from the specific embodiment and can be optionally combined with or substituted for features of any of several other embodiments disclosed herein.

[0014] With regard to the terms used herein, it should also be understood that the terms are intended to describe certain specific embodiments and do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps within a group of features or steps and do not impose sequential or numerical limitations. For example, "first," "second," and "third" features or steps do not necessarily have to appear in that order, and a particular embodiment including such features or steps is not necessarily limited to three features or steps. Designations such as "left," "right," "top," "bottom," "front," "back," etc. are used for convenience and are not intended to imply, for example, a specific fixed position, orientation, or direction. Instead, such designations are used to reflect, for example, a relative position, orientation, or direction. The singular forms "an," "a," and "the" include plural references unless the context clearly dictates otherwise. The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0015] With respect to "proximal," for example, the "proximal portion" or "proximal end portion" of a device disclosed herein includes the portion of the device intended to be near the user (e.g., a holder for the device). Similarly, for example, the "proximal length" of a device includes the length of the device intended to be near the user. For example, the "proximal end" of a device includes the end of the device intended to be near the user. The proximal portion, proximal end portion, or proximal length of a device may include the proximal end of the device, but the proximal portion, proximal end portion, or proximal length of a device need not include the proximal end of the device. That is, unless the context suggests otherwise, the proximal portion, proximal end portion, or proximal length of a device is not a terminal portion or terminal length of the device.

[0016] With respect to "distal," for example, a "distal portion" or "distal end portion" of a device disclosed herein includes a portion of the device intended to be opposite the user (e.g., "away from") the proximal portion. Similarly, for example, a "distal length" of a device includes the length of the device intended to be opposite the proximal portion and away from the user. For example, a "distal end" of a device includes the end of the device intended to be opposite the proximal end. A distal portion, end portion, or length of a device can include the distal end of the device, but a distal portion, end portion, or length of a device need not include the distal end of the device. That is, unless the context suggests otherwise, a distal portion, end portion, or length of a device is not a terminal portion or length of the device.

[0017] The embodiments described herein are generally directed to multi-lumen catheters that include one or more filler materials in a portion thereof. In some aspects, the one or more filler materials may act as a plug to block flow through the lumen in which it is located. In some aspects, the filler material may prevent bacterial growth or thrombus formation in the space between the lumen exit and the tip of the catheter. In some aspects, the one or more filler materials may be monofilaments formed by one or more extrusion processes.

[0018] Referring initially to Figure 1A, Figure 1A illustrates a catheter assembly, generally designated 10, configured in accordance with one embodiment. As shown, catheter assembly ("catheter") 10 includes an elongate catheter tube 12 formed by an outer wall 16 that defines, along with a septum 18 (Figure 1B), two or more lumens 14 extending longitudinally between a proximal end 12A and a distal end 12B of the tube. A bifurcation 20 mates with the catheter tube 12 at its proximal end 12A to provide fluid communication between the catheter tube and one or more extension legs 22.

[0019] FIG. 1B is a cross-sectional view of the catheter tube 12 of FIG. 1A in accordance with this embodiment. The catheter tube is aligned such that its width extends along the x-axis and its height extends along the y-axis, with the x-axis and y-axis depicted in FIG. 1B and selected subsequent figures. As shown, the tube 12 defines two lumens in a generally double-D shape in cross-section. Note that the corners 36 of each lumen 14, where the septum 18 joins the outer wall 16, are rounded to provide more laminar flow through the lumen. In the orientation shown in FIG. 1B, the tube 12 further defines an elliptical profile in cross-section, further defined by a minor axis 30 parallel to the x-axis and a major axis 32 parallel to the y-axis. Both the minor axis 30 and major axis 32, in this embodiment, are measured from the circumference or outer diameter ("OD") of the catheter tube outer wall 16, and each of the minor axis 30 and major axis 32 may lie in the same or different planes that bisect each lumen 14 of the double-D shaped tube 12. It should be noted that in this embodiment, the elliptical nature of the catheter tube exterior runs substantially the entire length of the tube, although in other embodiments the elliptical exterior may not run the entire length of the catheter tube.

[0020] Due to the oval nature of the catheter tube 12 as shown, the width of the septum 18 extending between opposing sides of the outer wall 16 to help define the two lumens 14 is shorter relative to the width of the septum in a correspondingly sized catheter tube having a circular cross-sectional profile. This allows the septum to be stiffer in an oval catheter tube, which helps prevent undesirable septum deflection when a pressure differential exists between the lumens, such as in dialysis applications. Optionally, this also allows the septum to be thinner relative to a septum in a circular catheter tube without compromising its deflection rate.

[0021] It should be noted that in the present embodiment shown in FIG. 1A , the bifurcation 20 provides a fluid path for establishing fluid communication between the extension leg 22, which has a circular cross-section, and the lumen of the oval catheter tube 12. Thus, in one embodiment, the fluid path defined within the bifurcation 20 may transition in cross-sectional shape from a generally circular shape proximate the extension leg 22 to a generally oval shape proximate the bifurcation connection point with the proximal end 12A of the catheter tube 12. This may further enhance fluid flow for the catheter assembly. In one embodiment, an oval core pin is used during manufacture of the bifurcation and catheter tube to provide an appropriately shaped fluid path within the bifurcation. Bifurcations in other embodiments may define fluid paths of other shapes. Indeed, in one embodiment, both the catheter tube and the extension leg may include oval cross-sectional shapes, and thus the bifurcation may define a fluid path of a substantially oval cross-section. These and other variations are contemplated.

[0022] 2 illustrates a cross-sectional view of a filler material 200 for use in occluding, blocking, or partially occluding a portion of a lumen 14 in a catheter tube 12, according to one embodiment of the present disclosure. The filler material 200 may be formed as a monofilament for use in occluding a portion of a catheter lumen during the manufacture or use of the catheter tube 12. In one aspect, the filler material 200 may be formed by an extrusion process, such as hot extrusion, cold extrusion, warm extrusion, friction extrusion, microextrusion, direct extrusion, indirect extrusion, hydrostatic extrusion, impact extrusion, and other extrusion processes that allow for the formation of a filler material having a desired cross-section. In another aspect, the filler material 200 may be formed by machining or molding a suitable material.

[0023] The filler material 200 may comprise any biocompatible polymeric material suitable for occluding or partially occluding a catheter lumen. Such materials include, but are not limited to, silicone, nylon, polyurethane, polyethylene terephthalate, latex, plastics, thermosets, and thermoplastic elastomers. In some embodiments, the filler material 200 may be formed from a suitable biocompatible metal. In some embodiments, the filler material 200 may comprise a radiopaque material.

[0024] The filler 200 may include a kidney-shaped cross section. The filler 200 may include a first convex portion 202, a second convex portion 206, a third convex portion 208, and a fourth convex portion 210. The filler 200 may also include a first concave portion 204 and a generally straight portion 212. In some embodiments, the first convex portion 202, the second convex portion 206, the third convex portion 208, the fourth convex portion 210, and the first concave portion 204 may each be defined by a curve having a radius. In some embodiments, at least some of the first convex portion 202, the second convex portion 206, the third convex portion 208, the fourth convex portion 210, and the first concave portion 204 may have curves that share the same or similar radius. In other embodiments, the first convex portion 202, the second convex portion 206, the third convex portion 208, the fourth convex portion 210, and the first concave portion 204 may each have a curve that includes a different radius. The unique cross-sectional shape of the filler material 200, which may be referred to as a "kidney-shaped cross-section," is specifically configured to replicate the shape of the lumen into which the filler material 200 may be placed. The kidney-shaped cross-section is intended to fill most, but not all, of the lumen. An example of this is shown in FIG. 3. The filler material 200 may have a length that extends the length of the catheter lumen or substantially the length of the lumen. Alternatively, the filler material 200 may have various lengths, such as 1 inch, 3 inches, 6 inches, or 12 inches.

[0025] FIG. 3 is a cross-sectional view of a catheter tube 12 including filler materials 300, 302 according to one embodiment. The catheter tube 12 may include multiple lumens, including a proximal lumen 14A, an intermediate lumen 14B, and a distal lumen 14C. The proximal lumen 14A may extend from a proximal portion of the catheter tube 12 to a proximal-most opening located along a portion of the catheter tube 12. The distal lumen 14C may extend from a proximal portion of the catheter tube 12 to a distal-most opening located along a distal portion of the catheter tube 12. The intermediate lumen 14B may extend from a proximal portion of the catheter tube 12 to an intermediate opening located between the proximal-most opening and the distal-most opening. Each of the proximal lumen 14A and the intermediate lumen 14B may include a kidney-shaped cross-section. The illustrated distal lumen 14C includes a generally triangular cross-section with rounded corners. In some embodiments, the distal lumen 14C may include a kidney-shaped cross-section substantially similar to the cross-sections of the proximal lumen 14A and the intermediate lumen 14B, and the proximal lumen 14A and the intermediate lumen 14B may include a generally triangular-shaped cross-section.

[0026] To occlude or fill portions of the proximal and intermediate lumens 14A, 14B of the catheter tube 12, filler materials 300, 302 may be inserted therein, and the filler materials 300, 302 may correspond to the filler material 200 described with reference to FIG. 2. The filler materials 300, 302 may include a kidney-shaped cross-section and be substantially similar to the filler material 200 shown in FIG. 2. In practice, the cross-sectional shape of the filler materials 300, 302 is intended to block most, but not all, of the lumens 14A, 14B. The cross-sections of the filters 300, 302 may correspond to the cross-sections of the proximal and intermediate lumens 14A, 14B. In some embodiments, the portions of the proximal or intermediate lumens 14A, 14B containing the filler materials 300, 302 may be located within the distal section of the catheter tube 12. In some embodiments, the portion of the proximal lumen 14A or intermediate lumen 14B containing the filler material 300, 302 may be located within the intermediate section of the catheter tube 12. In some embodiments, the portion of the proximal lumen 14A or intermediate lumen 14B containing the filler material 300, 302 may be located within the proximal section of the catheter tube 12.

[0027] When properly positioned, the filler materials 300, 302, which include cross sections identical or similar to the proximal and intermediate lumens 14A, 14B, can effectively occlude, block, or occlude the lumens 14A, 14B. As seen in FIG. 3 , the filler material 204 is properly positioned within the lumen 14B. However, in many cases, one or both of the filler materials 300, 302 may be improperly positioned during insertion into the lumens 14A, 14B. As seen in FIG. 3 , the filler material 300 is improperly positioned, for example, in a mirror-image or inverted position. Improper positioning of the filler material 300 reduces its effectiveness in occluding the lumen 14A and also distends the wall of the catheter tube 12 adjacent to the displaced filler material. For example, an improperly positioned filler material 300 distends points 304A, 304B, 304C, and 304D. This can adversely affect the structural integrity of the catheter tube 12, and particularly the walls of the lumens contained therein.

[0028] 4 is a cross-sectional view of a filler material 400 according to one embodiment of the present disclosure. The filler material 400 may be formed as a monofilament for use in occluding a portion of a lumen during the manufacture or use of the catheter tube 12. In one aspect, the filler material 400 may be formed by an extrusion process, such as hot extrusion, cold extrusion, warm extrusion, friction extrusion, microextrusion, direct extrusion, indirect extrusion, hydrostatic extrusion, impact extrusion, and other extrusion processes that allow for the formation of a filler material having a desired cross-section. In another aspect, the filler material 400 may be formed by machining or molding a suitable material.

[0029] The filler material 400 may comprise any suitable biocompatible polymer or other material for occluding or partially occluding the catheter lumen. Such materials include, but are not limited to, silicone, nylon, polyurethane, polyethylene terephthalate, latex, plastic, and thermoplastic elastomers. In some embodiments, the filler material 400 may be formed from a suitable biocompatible metal. In some embodiments, the filler material 400 may comprise a radiopaque material.

[0030] Unlike filler 200, filler 400 does not have a cross-section similar to the lumen into which it is inserted. Rather, filler 400 comprises a symmetrical cross-section. As shown in FIG. 4, filler 400 comprises an elliptical cross-section having apexes 402A-402B and minor apexes 404A-404B. Filler 400 includes a first line of symmetry 410 corresponding to an axis along the height h of filler 400 (e.g., measured along major axis 410). A second line of symmetry 412 corresponds to an axis along the width w of filler 400 (e.g., measured along minor axis 412). In some embodiments, first line of symmetry 410 has a length within a range of 0.0889 to 0.127 cm (0.035 to 0.050 inches). In some embodiments, first line of symmetry 410 has a range of 0.10414 ± 0.00508 cm (0.041 ± 0.002 inches). In one particular embodiment, the first line of symmetry 410 has a length of 0.041 inches. In some embodiments, the second line of symmetry 412 has a length in the range of 0.0175 to 0.035 inches. In some embodiments, the second line of symmetry 412 has a range of 0.0250 ± 0.0015 inches. In one particular embodiment, the second line of symmetry 412 has a length of 0.0250 inches.

[0031] 4 shows filler 400 having an oval cross-section, it should be understood that filler may include other shapes having at least one line of symmetry. For example, filler 400 may have an oval, rectangular, square, triangular, circular, or polygonal cross-sectional shape.

[0032] The symmetrical configuration of filler material 400 ensures that filler material 400 is not loaded into the lumen in an improper orientation, as opposed to, for example, misalignment of filler material 300 within lumen 14A as seen in FIG. 3. As discussed above, misalignment of filler material 300 can adversely cause swelling of the lumen wall. Additionally, the symmetrical shape of filler material 400 facilitates greater ease of manufacture by allowing for a simplified extrusion die.

[0033] FIG. 5 is a cross-sectional view of a catheter tube including multiple filler materials 500, 502, according to one embodiment. The filler materials 500, 502 may be substantially similar to the filler material 400 shown in FIG. 4. The catheter tube 12 may include multiple lumens, including a proximal lumen 14A, an intermediate lumen 14B, and a distal lumen 14C. The proximal lumen 14A may extend from a proximal portion of the catheter tube 12 to a proximal-most opening located along a portion of the catheter tube 12. The distal lumen 14C may extend from a proximal portion of the catheter tube 12 to a distal-most opening located along a distal portion of the catheter tube 12. The intermediate lumen 14B may extend from a proximal portion of the catheter tube 12 to an intermediate opening disposed between the proximal-most opening and the distal-most opening. Each of the proximal lumen 14A and the intermediate lumen 14B may include a kidney-shaped cross-section. The illustrated distal lumen 14C includes a generally triangular cross-section with rounded corners. In some embodiments, the distal lumen 14C may include a kidney-shaped cross-section similar to the cross-sections of the proximal lumen 14A and medical lumen 14B.

[0034] The filler material 500 may be inserted into a portion of the proximal lumen 14A to plug or block the lumen 14A at a desired location along the length of the proximal lumen. In some embodiments, the proximal lumen 14A may be blocked at a distal, intermediate, or proximal portion of the catheter tube 12. The symmetrical shape of the filler material 500 allows the filler material 500 to be positioned within the proximal lumen 14A without concern for imprecise insertion. Similarly, the filler material 502 may be inserted into a portion of the intermediate lumen 14B to plug or block the lumen 14B at a desired location along the length of the intermediate lumen. In some embodiments, the intermediate lumen 14B may be blocked at a distal, intermediate, or proximal portion of the catheter tube 12. The symmetrical shape of filler material 502 allows filler materials 500, 502 to be placed into proximal lumen 14B with little or no chance of improper placement within lumens 14A, 14B. Filler materials 500, 502 may have the same or different lengths and may extend along the desired length of lumens 14A, 14B.

[0035] In some embodiments, the portions of the proximal lumen 14A and the intermediate lumen 14B that include the filler materials 500 and 502, respectively, may be in the same location along the length of the catheter tube 12. In some embodiments, the portions of the proximal lumen 14A and the intermediate lumen 14B that include the filler materials 500 and 502, respectively, may be in different locations along the length of the catheter tube 12. For example, the filler material 500 may be in a distal section of the catheter tube 12, while the filler material 502 may be located in a middle section of the catheter tube 12. In some embodiments, the proximal lumen 14A or the intermediate lumen 14B may contain more than one filler material to occlude or block more than one section of the lumen.

[0036] Figure 6 shows a cross-section of a catheter tube 12 according to another embodiment, in which the elliptical outer shape is maintained as defined by the minor axis 30 and major axis 32, but the septum 18 of the tube is angled to define an angle θ with the minor axis 30. In one embodiment, the angled septum configuration shown in Figure 6 provides greater stability to the distal tip of the catheter during infusion of fluid through the catheter. The angled septum configuration further balances the major axis of the catheter tube, thus reducing the likelihood that the catheter tube will roll or bend in only one direction.

[0037] The catheter tube 12 of Figure 6 includes a filler material 600 disposed in a portion of the lumen 14. The filler material 600 may have an elliptical cross-section that includes a first line of symmetry 604. The first end 601 includes a diameter that is smaller than the diameter of the second end 602. As described above with reference to the filler materials 200, 400, the filler material 600 may be formed as a monofilament of a desired biocompatible material. The filler material 600 may extend along a desired length of the lumen 14.

[0038] FIG. 7 illustrates a cross-section of another embodiment of a catheter tube 12, in which the elliptical outer shape defined by the minor axis 30 and major axis 32 is maintained, but the tube defines three lumens 14A, 14B, and 14C in a triple-lumen configuration. As shown, the septum 18 branches adjacent to either side of the generally triangular third lumen 14C. As with dual-lumen catheter tubes, the triple-lumen configuration shown here improves the flow rate of each of the lumens 14A, 14B, and 14C due to the catheter tube's elliptical outer shape. Note that in one embodiment, one or more of the lumens 14A-14C may be configured for relatively high fluid flow rates therethrough, commonly referred to as power injection. Indeed, in other embodiments described herein, one or more of the catheter tube's lumens may be configured to withstand power injection.

[0039] Lumens 14A, 14B are illustrated as including filler materials 702 and 704, respectively, along portions thereof. Filler materials 702 and 704 may be similar to filler material 400 described above. However, filler materials 702 and 704 may include similar cross-sections but have different sizes. For example, filler materials 702, 704 may have an elliptical cross-section, but filler material 702 may have a smaller width or length than filler material 704. Such variations allow for different levels of blockage or occlusion for each lumen 14A, 14B. Filler materials 702, 704 may have the same or different lengths and may extend along the desired length of lumens 14A, 14B.

[0040] Figure 8 shows a cross-section of a catheter tube 12 according to another embodiment, in which an elliptical outer shape is maintained as defined by a minor axis 30 and a major axis 32. The tube defines three lumens 14A, 14B, and 14C in a triple lumen configuration, as in Figure 7, with septa 18 branching adjacent either side of a circular third lumen 14C. Again, as with the dual lumen catheter tube, the triple lumen configuration shown herein improves the flow rate in each of the lumens 14A, 14B, and 14C due to the elliptical outer shape of the catheter tube.

[0041] In contrast to the configuration of Figure 7, the catheter tube 12 of Figure 8 includes a portion 50 that defines the portion of the outer wall 16 that abuts the third lumen 14C and a portion of the septum 18. The portion 50 extends longitudinally of the catheter tube and includes a material that is relatively harder than the material that defines the septum 18 and the remainder of the outer wall 16. This relatively harder material reinforces the third lumen 14C, enabling it to withstand the high fluid pressures typically associated with power injection.

[0042] Additionally, in one embodiment, the material included in portion 50 allows portions of outer wall 16 and septum 18 to be thinner than would be possible with other materials, and allows the other lumens 14A and 14B to be larger than would be possible with other materials. In other embodiments, the material defining portion 50 may also be harder and / or include greater tensile strength than the other portions of the outer wall and septum to provide desired properties for the third lumen. In yet another embodiment, portion 50 may extend to surround the entire septum 18.

[0043] It should be noted that, as with the oval dual lumen configuration described above, the width of the septum 18 in the triple and quadruple lumen configurations described herein is shorter compared to a septum in a catheter tube of corresponding size having a circular cross-sectional profile, again strengthening the septum and thereby helping to prevent undesired septum deflection when a pressure differential exists between the lumens.

[0044] In one embodiment, for example, catheter portion 50 comprises a material having a hardness of approximately 100 Shore A, while the remainder of the catheter tube 12 comprises a material having a hardness of approximately 85 Shore A. Thermoplastic polyurethanes, including those sold under the names TECOTHANE® and CARBOTHANE®, are non-limiting examples of materials that may be configured to meet these or other desired hardness characteristics for portion 50 and the remainder of the catheter tube 12. The catheter tube 12 shown and described herein can be formed by coextrusion, insert extrusion, and other suitable methods.

[0045] Additionally, the catheter tube 12 of FIG. 8 may include multiple filler materials 800A, 800B disposed within the same lumen 14A over a portion thereof. Filler material 800A may have a square or rectangular cross-section having a first line of symmetry 801 and a second line of symmetry 802. Filler material 800B may have a triangular cross-section having a first line of symmetry 803, a second line of symmetry 804, and a third line of symmetry 805. Filler materials 800A, 800B may be inserted simultaneously into the lumen 14A at the same portion of the lumen 14A so as to together block or occlude the lumen 14A. Using multiple filler materials with various cross-sections within the same lumen, each with at least one line of symmetry, may enable more complete blockage of the lumen at the desired location.

[0046] 9 shows a cross-section of a catheter tube 12 according to another embodiment, in which the elliptical outer shape is maintained as defined by the minor axis 30 and major axis 32, but the tube now defines four lumens 14A, 14B, 14C, and 14D in a quadruple lumen configuration. As shown, two bulkheads 18A and 18B intersect with each other and, together with the outer wall 16, define the four lumens 14A-14D. As previously mentioned, one or more of the lumens 14A-14D may be configured for power injection, with flow through the lumens being optimized due to the elliptical aspect ratio of the catheter tube 12.

[0047] As shown in FIG. 9 , the catheter tube 12 includes multiple filler materials 901, 902, and 903. Each of the filler materials 901, 902, and 903 includes a triangular cross-section and at least one line of symmetry. For example, filler materials 901 and 903 share a line of symmetry along the minor axis 30, and filler material 902 includes a line of symmetry along the major axis 32. The filler materials 901 and 903 may have a first size, and filler material 902 may have a second size larger than the first size. The filler materials 901, 902, and 903 may be positioned at different or the same location along the length of the catheter tube 12. In one embodiment, the lengths of the filler materials 901, 902, and 903 may be the same. In another embodiment, the lengths of the filler materials 901, 902, and 903 may be different.

[0048] FIG. 10 shows a cross-section of a catheter tube 12 according to another embodiment, in which an oval outer shape is maintained as defined by the minor axis 30 and the major axis 32. Also shown is a septum 58 dividing the two lumens 14. Each lumen 14 may include a filler material 400 disposed along a portion thereof. The septum 58 is initially relaxed when the catheter tube 12 is in a resting state as shown in FIG. 10. This allows the oval catheter tube 12 to be fed through a circular catheter introducer, such as the introducer 60 shown in FIG. 11. In particular, FIG. 11 shows the catheter tube 12 of FIG. 10 being introduced into the proximal end of the introducer 60. The introducer 60 includes a circular body 62, a portion of which is initially positioned within the patient's blood vessel.

[0049] By introducing the oval catheter tube 12 into the circular introducer 62, the lumen 14 is blocked, occluded, or occluded as the tube outer wall 16 is deformed to the circular shape of the introducer body and conforms to the surface of the filler material 400. The septum 58 is initially in a relaxed state, allowing the catheter tube 12 to deform from an oval shape to a circular shape as it enters the circular introducer body 62. This causes the initially relaxed septum 58 to become taut as the outer body 16 of the catheter tube 12 is circularized, as shown in FIG. 12, which shows the catheter tube 12 positioned within the introducer body 62. This allows the catheter tube 12 to be inserted into the patient's blood vessel, after which the introducer 60 is removed from the vessel and the catheter tube resiliently returns to its oval aspect (FIG. 10).

[0050] In one embodiment, the introducer and / or the proximal portion of the introducer body may include a transition region that gradually changes from an oval to a circular profile to facilitate insertion of an initially oval catheter tube into the introducer. In another embodiment, an oval introducer may be used to place an oval catheter tube into a patient's vasculature. Note that the relaxed shape of the septum may differ from the wavy configuration shown in FIG. 10 and may include, for example, an arched or arcuate shape.

[0051] 13A and 13B show side and top views, respectively, of a catheter assembly 10 according to one embodiment, in which the dual-lumen catheter tube 12 includes a proximal section 64 extending distally from the bifurcation 20 and a distal section 66 extending distally from the distal end of the proximal section to the distal tip of the catheter tube. In particular, the proximal section 64 of the illustrated embodiment includes a circular cross-sectional profile, as seen in cross-section in FIG. 14A. The distal section 66 of the catheter tube includes an elliptical cross-sectional profile, as seen in cross-section in FIG. 14B, similar to the configuration shown in FIG. 1B.

[0052] The catheter tube 12 may also include one or more filler materials 400, 1000 disposed in various portions of the lumen 14. As shown in FIG. 14A , the filler material 400 may be disposed within a portion of the lumen 14 at the proximal portion 64 of the catheter tube. Additionally, the filler material 1000 may be disposed within the lumen 14 at the distal portion 66. The filler material 1000 may include a rectangular cross-section with rounded corners 1001. In some aspects, the filler material 400 and the filler material 1000 may be disposed at different locations along the same lumen.

[0053] 13A and 13B, the distal portion 66 has an increased diameter relative to the proximal portion 64 due to the oval nature of the distal portion, as best seen in the top view of FIG. 13B. In one embodiment, this provides a desired low hydraulic resistance in the distal portion of each lumen 14, as well as enhanced power injection behavior (e.g., lower power injection pressures and greater distal tip stability). Additionally, the circular proximal portion 64 of the catheter tube of FIG. 13A and 13B is less likely to invert when the catheter tube is manipulated within the vasculature during and after the placement procedure.

[0054] Thus, it is understood that portions of the catheter tube may include an oval profile while other portions do not. It is understood that in another embodiment, the positions of the circular and oval portions of the catheter tube may be reversed. In yet another embodiment, the average diameter of the proximal or distal portion of the catheter tube may be larger relative to the other. More generally, the size, number, length, number of lumens, and placement of one or more oval portions of the catheter tube may be varied as understood by those skilled in the art. Furthermore, it is understood that the nature and / or extent / magnitude of the oval profile may vary over the length of the catheter tube. Further details regarding catheters, including features for improving distal tip stability, can be found in U.S. Patent Application No. 13 / 209,270, filed August 12, 2011, and entitled "Trimable Catheter Including Distal Portion Stability Features," which is incorporated herein by reference in its entirety.

[0055] FIG. 15 illustrates an exemplary method of manufacturing a catheter 150 including a distal tip structure 170 having one or both of a PIV section 154 and a dilator section 158. An exemplary method, referred to as "tipping," in which the distal tip structure 170 is coupled to a central venous catheter (CVC) section 156 to form the catheter body 156 can form a CVC section 156 having one or more lumens 114A-114C. In one embodiment, the CVC section 156 may be extruded and then trimmed to the desired length. However, it should be understood that other methods of forming the CVC section 156 are also contemplated. As shown in FIG. 15, a triple-lumen CVC section 156 is provided, including a first (proximal) lumen 156A, a second (middle) lumen 114B, and a third (distal) lumen 114C. However, it should be understood that other single-lumen or multi-lumen catheters 150 are also contemplated. It should be noted that the lumens 114A, 114B, 114C of the CVC section 156 may be arranged radially about the central axis of the CVC section 156. In Figure 15, the lumens 114A, 114B, 114C are shown adjacent to one another for clarity, however, it should be understood that other configurations of the multi-lumen catheter 150 are contemplated.

[0056] In one embodiment, a plug or filler material may be disposed in one or both of the proximal lumen 114A and the intermediate lumen 114B. For example, a first plug or filler material 252A may be disposed in the distal end of the first lumen 114A, and a second plug or filler material 252B may be disposed in the distal end of the second lumen 114B. The first plug or filler material 252A or the second plug or filler material 252B may take the form of any of the fillers described above and may include a filler material having at least one line of symmetry. The distal tip 254 of the first plug or filler material 252A may be aligned with the distal end 218 of the CVC segment 156. Optionally, the distal tip 254 of the second plug or filler material 252B may be trimmed to align with the distal end 218 of the CVC segment 156.

[0057] The distal tip structure 170 may then be coupled to the distal end 218 of the CVC section 156 using adhesives, bonding, solvent bonding, welding, etc. The lumen of the distal tip structure 170 may align with the lumen of the CVC section 156 to form a distal lumen 114C extending to a distal lumen opening 116C. A first plug or filler material 252A may seal the proximal lumen 114A, and a second plug or filler material 252B may seal the intermediate lumen 114B proximal to the dilator section 158. A proximal lumen opening may then be formed through the wall of the catheter body or CVC section 156 to communicate with the proximal lumen 114A. An intermediate lumen opening may then be formed through the wall of the catheter body or CVC section 156 to communicate with the intermediate lumen 114B.

[0058] These and other variations of the principles described herein are contemplated, and it should be understood that the cross-sectional profiles of the multi-lumen catheter tubes disclosed herein may be varied as understood by those skilled in the art.

[0059] Although some specific embodiments have been disclosed herein, and the specific embodiments have been disclosed in some detail, the specific embodiments are not intended to limit the scope of the concepts provided herein. Additional adaptations and / or modifications may be apparent to those skilled in the art, and the broader aspects encompass these adaptations and / or modifications as well. Thus, departures may be made from the specific embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

1. 1. A system comprising: a catheter, the catheter comprising: an elongated tube including a distal end and defining a plurality of lumens; a distal tip structure located adjacent the distal end; a first plug of filler material configured to be disposed within a first portion of a first lumen of the plurality of lumens proximal to the distal tip, the first plug being defined as having an oval cross-sectional shape.

2. 10. The system of claim 1, further comprising a second plug of filler material disposed within a second portion of one of the plurality of lumens, the second plug being defined as having the oval cross-sectional shape.

3. The system of claim 2 , wherein the first plug and the second plug are disposed in different lumens.

4. The system of any one of claims 1 to 3, wherein the first plug is formed from a biocompatible polymeric material.

5. The system of claim 4 , wherein the biocompatible polymeric material comprises one or more of silicone, nylon, polyurethane, polyethylene terephthalate, latex, plastic, thermoset, or thermoplastic elastomer.

6. The system of any one of claims 1 to 3, wherein the first plug is formed from a radiopaque material.

7. The system of any one of claims 1 to 6, wherein the first plug includes a cross section having a first line of symmetry.

8. 8. The system of claim 7, wherein the length of the first line of symmetry is within the range of 0.0889 to 0.127 cm (0.035 to 0.050 inches).

9. 9. The system of claim 8, wherein the length of the first line of symmetry is 0.10414±0.00508 cm (0.041±0.002 inches).

10. The system of any one of claims 7 to 9, wherein the first plug includes a cross section having a second line of symmetry.

11. 11. The system of claim 10, wherein the length of the second line of symmetry is within the range of 0.0175 to 0.035 inches.

12. 12. The system of claim 11, wherein the length of the second line of symmetry is 0.0250±0.0015 inches.

13. 13. The system of claim 1, wherein the elliptical cross-sectional shape of the first plug includes a first apex and a second apex, and the first plug is configured such that either the first apex or the second apex can be positioned near an upper side of the first lumen without causing distension of a wall of the lumen.

14. The system of any one of claims 1 to 13, wherein the first portion of the first lumen is located within a distal section of the catheter.

15. The system of any one of claims 1 to 13, wherein the first portion of the first lumen is located within an intermediate section of the catheter.

16. The system of any one of claims 1 to 13, wherein the first portion of the first lumen is located within a proximal section of the catheter.

17. 17. The system of claim 1, wherein the plurality of lumens includes the first lumen, the second lumen, the third lumen, and the fourth lumen, at least two of the plurality of lumens are bisected by a plane containing one of the minor axis or the major axis of the catheter, and at least one of the plurality of lumens is capable of power injection.

18. The system of any one of claims 1 to 17, wherein a proximal portion of the elongate tube defines a circular cross-section and a distal portion of the elongate tube defines an elliptical cross-section.

19. The system of any one of claims 1 to 17, wherein a proximal portion of the elongate tube defines an elliptical cross-section and a distal portion of the elongate tube defines a circular cross-section.

20. The system of any one of claims 1 to 17, wherein the plurality of lumens comprises a cross-sectional profile that is generally triangular or kidney-shaped.

21. The system of any one of claims 1 to 20, wherein the catheter is an acute central venous catheter.

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