BACKGROUND OF THE INVENTION
The present invention relates generally to a catheter. More particularly the present invention relates to a reinforced catheter having a radiopaque distal tip, and still more particularly, relates to kink-resistant, flat-wire reinforced catheter having a soft radiopaque distal tip.
Percutaneous interventional procedures often require the use of catheters to negotiate, i.e. pass through, arteries, veins or interstitial spaces from the site of entry into the body to the site requiring treatment or study. The catheter may either provide a conduit for delivery of therapeutic devices like angioplasty systems, stent delivery systems, pacing leads, guide wires, biopsy devices or intravascular ultrasound devices; or provide a mode for drug or fluid delivery. Introducer sheaths or introducer catheters or guiding catheters, for instance, are of this type. In other instances, the catheter may be part of the therapeutic device, e.g., some of the aforementioned.
Such catheters are often required to be highly flexible, kink resistant, pushable and of minimal wall thickness. The distal tips of such catheters are often required to track a guide wire while minimizing trauma within the body. In addition, physicians often expect the distal tip as well as any other portion of the catheter that is placed in the body, to be identifiable under fluoroscopy (radiopaque) enabling visual feedback during the positioning and use of the catheter.
The present invention provides a catheter that is highly flexible, kink-resistant, pushable, of minimal wall thickness, reinforced with a coil spring of radiopaque material, and tracks a guide wire with a soft, atraumatic, radiopaque distal tip.
SUMMARY OF THE INVENTION
A catheter, including: a reinforced tube including a plurality of concentric bonded tubular layers of non-radiopaque material and a radiopaque, coil spring captured between adjacent ones of the tubular layers, one end of the reinforced tube providing an annular mounting portion and a tubular mounting member extending outwardly of the annular mounting portion; and a tapered tip of radiopaque material including a tip central portion providing a tip central passageway receiving the tubular mounting member and a tip mounting portion abutting and bonded to the annular mounting portion, the tip central portion bonded to the tubular mounting member.
The process of manufacturing a catheter, including the steps of providing a reinforced tube including a plurality of concentric bonded tubular layers of non-radiopaque material and a radiopaque, coil spring captured between adjacent ones of the tubular layers, providing an annular mounting portion at one end of the reinforced tube and providing a tubular mounting member extending outwardly of the annular mounting portion, and providing a tapered tip of radiopaque material including a tip central portion providing a tip central passageway and a tip mounting portion, bonding the tip mounting portion to the annular mounting portion and bonding the tip central portion to the tubular mounting member.
BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of the invention may be had by reference to embodiments of the invention illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
FIG. 1 is an outline view of the first embodiment of a catheter embodying the present invention;
FIG. 2 is a longitudinal cross-sectional view of the catheter of FIG. 1;
FIG. 3 is an exploded view showing the distal end of the reinforced tubing of the catheter in cross-section and showing a tapered radiopaque distal tip in perspective;
FIG. 4 is a right side, end view of the distal portion of the reinforced tubing shown in FIG. 3 without the distal tip.
FIGS. 5-10 illustrate a process for manufacturing the catheter shown in FIGS. 1-4;
FIG. 11 is an outline view of a further embodiment of a catheter embodying the present invention;
FIG. 12 Is a longitudinal cross-sectional view of the catheter shown in FIG. 11;
FIG. 13 is an exploded view showing the distal portion of the reinforced tubing in cross-section comprising the catheter embodiment shown in FIG. 11 and showing the tapered radiopaque distal tip in perspective; and
FIG. 14 is a right side, end view of the reinforced tubing shown in cross-section in FIG. 13 without the distal tip.
DETAILED DESCRIPTION
A first embodiment of a catheter embodying the present invention is illustrated in FIGS. 1 and 2 and is identified by general numerical designation 10; the catheter is provided with a central catheter passageway 10A. The catheter 10 includes a proximal portion indicated by general numerical designation 12 and a distal portion indicated by general numerical designation 14. The proximal portion Is to the left of the diagrammatical line 15 shown in FIGS. 1 and 2, and the distal portion is to the right of the vertical line 15. The vertical line 15 is for indicating, diagrammatically, the approximate demarcation between the proximal portion 12 and the distal portion 14 of the catheter 10. The proximal portion 12 may include a hub or adapter, indicated by general numerical designation 16 and a cylindrical proximal reinforced tube or tubing indicated by general numerical designation 17. The hub 16 may, or may not, include a hemostasis valve, indicated diagrammatically by numerical designation 16A, and which may be any one of several hemostasis valves known to the art for, by way of example, sealing around the outside surface of, such as for example, a guide wire when it is in place in the catheter passageway 10A to prevent loss of fluid or entry of air embolism. The distal portion of the catheter 10 includes a tapered or tapered radiopaque distal tip indicated by general numerical designation 18.
Referring to FIG. 2, the reinforced tube 17 includes a central tubular layer 20, of low friction, non-radiopaque material, extending through the catheter proximal portion 12 and through the catheter distal portion 14, as shown, and providing a catheter central passageway 10A An inner tubular layer 22, of non-radiopaque material, surrounds and is bonded to the inner tubular layer 20 and also extends through the catheter proximal catheter portion 12 and through the catheter distal portion 14 as shown. An outer tubular layer 24, of non-radiopaque material, surrounds and Is bonded to the inner tubular layer 22 and, as shown in FIG. 2, extends only through the catheter proximal portion 12. It will be understood from FIG. 3, that the outer tubular layer 24 includes a distal portion or annular tube mounting portion 25, providing, as shown in FIGS. 3 and 4, a tube annular mounting surface 26. The annular tube mounting portion 25 and the tube annular mounting surface 26, as described in detail below, are for mounting the distal tip 18 to the reinforced tube 17. As will be further understood from FIGS. 2 and 3, and as noted above, the central tubular layer 20 and the inner tubular layer 22 include portions extending into the catheter distal portion 14 and which portions, as will be particularly understood from FIG. 3, combine to provide a tubular mounting member indicated by general numerical designation 34. As described in detail below, the tubular mounting member 34 also is for mounting the distal tapered tip 18 to the reinforced tube 17.
The reinforced tube 17, FIG. 2, further includes a radiopaque, coil spring identified by general numerical designation 30 and which radiopaque, coil spring is indicated diagrammatically in FIG. 2 by the opposed rows of dark dashes 32; the dark dashes 32 also indicate, diagrammatically, the turns of the coil spring 30 which have spaces or gaps therebetween. Preferably, the coil spring is a flat-wire coil spring made from radiopaque, flat wire, such as for example, 304 stainless steel, about 0.003 inch to about 0.005 inch thick and which has a width that is less than about 4 times the thickness. As further indicated diagrammatically in FIG. 2, the radiopaque, coil spring 30 is captured between the outer tubular layer 24 and the inner tubular layer 22 with portions of the outer tubular layer 24 filling some of the gaps between the turns of the coil spring 30 and with portions of the inner tubular layer 22 filling other of the gaps. The coil spring 30 provides kink and crush resistance to the catheter 10, contributes to the flexibility of the catheter, facilitates a thin wall section for the catheter, and provides radiopacity for the proximal portion of the catheter.
The tapered distal tip 18 of radiopaque material, FIGS. 2 and 3, and particularly FIG. 3, includes a tip central portion 36 providing a tip central passageway 38 for receiving, as shown in FIG. 2, the tubular mounting member 34, and further includes a proximal portion, or tip mounting portion 40, providing a tip annular mounting surface 41. As shown in FIG. 2, and as described in detail below, the tip mounting portion 40 abuts and is bonded to the annular mounting portion 25 of the outer tubular layer 24, more particularly the tip annular mounting surface 41 (FIG. 3) abuts and is bonded to the annular mounting surface 26 (FIG. 3) of the outer tubular layer 24; the tip central portion 36 (FIG. 3) is bonded to the tubular mounting member 34 (FIG. 3) and, in particular, directly to the distal portion of the inner tubular layer 22.
Referring further to FIG. 2, the central tubular layer 20 may be a tubular layer of suitable low friction, non-radiopaque thermoplastic material, such as for example, fluoroethylene-propylene (FEP) or polytetrafluoroethylene (PTFE) which are low friction and non-radiopaque materials which will provide a lubricious conduit, e.g., catheter central passageway 10A, for medical devices of the type mentioned above passing through the catheter central passageway 10A. In the preferred embodiment, the central tubular layer 20 has a thickness of about 0.0005 inch to about 0.002 inch prior to fusing or bonding as described below.
The inner tubular layer 22 may be a suitable tubular layer of non-radiopaque thermoplastic material such as, for example, polyether block amide having a durometer of about 20 to about 30 on the Shore D scale. The outer tubular layer 24 may be a suitable tubular layer of non-radiopaque material such as polyether block amide having a durometer of about 50 to about 70 on the Shore D scale. In the preferred embodiment the inner tubular layer 22 has a thickness of about 0.001 inch to about 0.003 inch prior to fusing or bonding as described below. The wall thickness of the harder outer tubular layer 24 is dependent on the desired wall thickness and desired stiffness of the catheter, however in the preferred embodiment the outer tubular layer 24 had a thickness of about 0.0025 inch to about 0.005 inch prior to bonding as described below. The harder outer tubular layer 24 provides a smooth, non-tacky outer surface to the catheter 10 that is desirable for traversing the cardiovascular system or interstitial spaces. The softer inner tubular layer 22 is a tackler material than the harder outer layer 24 but of the same material family and thereby facilitates bonding to the harder outer layer 24. Still further, the polyether block amide of the outer tubular layer 24 may be compounded with light or processing stabilizers, or a colorant if desired.
The tapered distal tip 18 may be made of a suitable thermoplastic material filled with a suitable radiopaque agent such as, for example, polyether block amide having a durometer of about 30 to about 45 on the Shore D scale and which is filled with about 70% to about 90% by weight tungsten to make the tip radiopaque. This radiopaque material of the noted durometer provides a smooth, non-tacky surface that is desirable for traversing the cardiovascular system or interstitial spaces and further contributes to the flexible, atraumatic distal tip that facilitates tracking a guide wire.
A process for manufacturing the catheter 10 is illustrated in connection with FIGS. 5-10. Referring to FIG. 5, the central tubular layer 20 is extruded over a cylindrical mandrel (not shown), the inner tubular layer 22 is extruded over the central tubular layer 20, the radiopaque, coil spring 30 is wound over the inner tubular layer 22 and the outer tubular layer 24 is extruded over the radiopaque, coil spring 30 and the inner tubular layer 22. The sub-assembly shown in FIG. 5 and which sub-assembly is indicated by general numerical designation 50 is then inserted in a suitable shrink tubing or jacket indicated diagrammatically by the surrounding irregular line balloon in FIG. 5 and indicated by general numerical designation 52; the shrink tubing may be, for example, fluoroethylene-propylene(FEP) shrink tubing. The shrink tubing wrapped sub-assembly 50 is suitably heated for a suitable period in the manner known to the art for bonding or fusing thermoplastic materials using heat shrink tubing. This heat shrink process step bonds the inner tubular layer 22 to the outer tubular layer 24 capturing the radiopaque, coil spring 30 between the inner tubular layer 22 and the outer tubular layer 24 as shown in FIG. 6 with portions of the inner tubular layer 22 filling some of the gaps or spaces between adjacent turns of the radiopaque, coil spring 30 and with portions of the outer tubular layer 24 filling other of such spaces or gaps. The sub-assembly 50 is cooled and the shrink tubing 52 removed. Then, the mandrel is removed.
As shown in FIG. 6, the rightward end portions of the outer tubular layer 24 and the coil spring 30 are suitably removed such as by trimming away material to provide the tube mounting portion 25 and the annular mounting surface 26 and to expose the rightward end portions of the central tubular layer 20 and the inner tubular layer 22 to provide the tubular mounting member 34. A hollow cylindrical tube, or tubular layer, indicated by general numerical designation 18A, and shown in cross-section in FIG. 7, is provided of the material noted above for the tapered distal tip 18 and which tube 18A includes a central portion 36 providing the tip central passageway 38, the tip mounting portion 40 and the annular tip mounting surface 41. Thereafter, the cylindrical tube 18A is placed, or slides, over the tubular mounting member 34 to cause the mounting portion 40 of the tip 18A to abut the annular mounting portion 25 of the outer tubular layer 24, and more particularly, to cause the distal tip annular mounting surface 41 to engage the tube annular mounting surface 26, and to cause the distal tip central passageway 38 to receive the tubular mounting member 34 with the tip central portion 36 engaging the tubular mounting member 34, particularly the inner tubular member 22; this provides an assembly indicated by general numerical designation 54 in FIG. 8. The assembly 54 is inserted, as indicated by the arrow 55 in FIG. 9, into a heated tipping die, indicated by general numerical designation 60 in FIG. 9, to mold the rightward portion of the assembly 54 into the desired shape for the rightward end portion of the catheter 10 (FIG. 1), particularly into the desired end shape for the tapered distal tip 18. The tipping die 60 is heated to a temperature of about 150 C to about 210° C. to provide the tube 18A (FIG. 7) of the above-noted radiopaque material with the desired tapered shape of the tapered distal tip 18 as shown in FIG. 10, and to bond the distal tip annular mounting surface 41 (FIG. 3) to the tube annular mounting surface 26 (FIG. 3) and bond the distal tip central portion 36 (FIG. 7) to the tubular mounting member 34 (FIG. 6), particularly to the inner tubular layer 22 (FIG. 8). The rightward portion of the catheter 10 is removed from the tipping die 60 and cooled, and any required final trim operation is performed. It will be understood that the outer ends of the outer tubular layer 24 and the radiopaque, coil spring 30 can be prepared to provide the tubular mounting member 34 (FIG. 6) either before or after the heat shrink tubing process step described above. If the tubular mounting member 34 is prepared before, the tube 18A can also be added before the heat shrink tubing process.
In an alternate process of manufacturing the catheter 10, the tubular layers 20, 22 and 24 of FIG. 5 are provided as individual tubular layers and assembled as shown in FIG. 5, with the radiopaque, coil spring 30 wrapped around the inner tubular layer 22, to provide the sub-assembly 50. Thereafter the same process manufacturing steps described above in connection with FIGS. 5-10 are practiced or performed
Referring again to FIG. 2, the hub or adapter 16 is suitably formed into the shape shown such as being molded from a suitable thermoplastic material such as Isoplast or machined from a block of such thermoplastic material. The hub 16 is provided with the hemostasis valve 16A and is bonded or attached to the reinforced tube 17 by heat bonding or by a suitable adhesive known to the art for adhering plastic parts together.
A further embodiment of a catheter embodying the present invention is illustrated in FIGS. 11-14 and indicated by general numerical designation 10B. Catheter 10B includes reinforced tube or tubing 17B, hub 16 and tapered distal tip 18 of radiopaque material. It will be understood that the elements or components comprising the catheter 10B which are the same as the elements or components comprising the catheter 10 shown in FIGS. 1-4 are given the same numbers in FIGS. 11-14 and will be understood to perform the same functions. Catheter 10B differs from catheter 10 in that the reinforced tube or tubing 17B does not include the inner tubular layer 22 of non-radiopaque material shown in FIGS. 24. Since the inner tubular layer 22 is not included in the reinforced tube or tubing 17B, it will be understood from FIG. 12 that the outwardly extending distal portion of the central tubular layer 20 provides the tubular mounting member 34 to which, the tapered distal tip 18 is bonded. It will be further understood that the process for manufacturing the catheter 10B is the same as the process described above for manufacturing the catheter 10 except that the inner tubular layer 22 of the catheter 10 is not incorporated in the manufacturing process for the catheter 10B.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Patent Application
20080108974
