Patent Grant
8465469
The present invention relates to reinforced catheters, and to methods of making the same. More particularly, the invention involves catheters used for accessing coronary, cerebral or other peripheral arteries for diagnostic or therapeutic procedures.
Among the therapeutic procedures applicable to the present invention are percutaneous transluminal coronary angioplasty (PTCA) and stenting. These procedures can be used, for example, to reduce arterial build-up of cholesterol fats or atherosclerotic plaque. During such an intervention, a guiding catheter is used to form a direct conduit from outside a patient's body, through the vasculature to the site targeted for treatment or to the ostium of the diseased artery. Before performing an intervention, an angiography catheter may be utilized to diagnose the patient's symptoms by injecting radiopaque contrast into suspected arteries, creating fluoroscopic images.
Guiding catheters and angiography catheters must have sufficient bending stiffness to be pushed through vessels as well as sufficient torsional rigidity to provide a high degree of torsional control. It is also desirable for a catheter to have a soft or flexible distal tip to avoid dangers of puncturing or otherwise damaging a vessel as it twists through the vascular system. Examples of such soft tip catheters are known in the art. Guiding catheters and angiography catheters generally are formed as a three-layer composite tube. The first layer is a hollow liner, which, in the case of a guiding catheter, is provided with a lubricious inner surface to aid in device passage through the lumen of the catheter. The next layer is a reinforcing material, typically a stainless steel wire that is braided around the liner. An outer jacket encapsulates the braid and is bonded to the liner through braid interstices to create a monolithic structure from the three components.
The trend in the field of the invention has been toward catheters having thinner walls with a goal of providing a larger lumen, a smaller outside diameter, or both. While improvements in polymeric materials used for catheter liners and/or jackets have helped in the achievement of thinner walls, the thickness of the common braided reinforcement layer has become a limitation to further progress in this area. To create a woven braid, filaments must be passed over other filaments, giving the reinforcement layer, in effect, twice the thickness of the filaments. Additionally, despite their encapsulation between the outer jacket and the liner, braid filaments are not secured together at their intersections, so that the filaments can shift relative to each other, thus diminishing physical properties of the catheter such as torsional stiffness and kink resistance.
The prior art includes references that teach forming a catheter reinforcement layer by spirally wrapping a perforated film around a liner, or by rolling a patterned sheet to form a catheter tube. To create an uninterrupted layer of reinforcement material, such examples require a double-thickness overlapping seam or an unsecured butt seam, which has compromised physical properties. Thus, there is a continuing need for improvements in reinforced catheters having reduced wall thickness while maintaining good or improved properties of stiffness, torque transfer characteristics and high kink resistance.
The invention provides a reinforced catheter having a non-filamentous, seamless metal tube interposed between a polymeric hollow core and a polymeric outer jacket. The metal tube may have a pattern of apertures through which the hollow core and the polymeric outer jacket are adhered to each other. The metal tube forms a reinforcement layer that can be thinner than is practically achievable by known filamentous reinforcements.
Features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where:
The drawings are not to scale.
Hollow core 20 and/or outer jacket 30 may comprise polymeric materials such as polyolefins, thermoplastic polyurethanes, polyamides, thermoplastic elastomers, fluoropolymers, or blends, laminates, copolymers and/or block copolymers thereof. A polymer that is thermoplastically extrudable may be selected for advantages such as processing cost efficiency and the ability to be melt-bonded. Hollow core 20 may be extruded over a metal or plastic mandrel (not shown), which can be removed later during manufacturing. To make guiding catheters, it may be desirable to form hollow core 20 from a paste extrudable fluoropolymer such as polytetrafluoroethylene (PTFE), which provides a low friction surface for the catheter lumen. A slippery lumen can also be provided, however, by applying lubricious coating 40 to the inner surface of hollow core 20, as shown in
Metal tube 25 is a non-filamentous, seamless reinforcement layer that has been formed on, and is adherent to the external surface of hollow core 20. The method of forming metal tube 25 may comprise a metallizing process such as electroplating, electroless plating, sputter coating, vapor deposition, or combinations thereof. Hollow core 20 may receive chemical or other surface treatments to enhance adhesion of metal tube 25 thereto, as will be understood by those familiar with techniques of metallizing plastics. Optionally, hollow core 20 may comprise a polymer matrix containing particles that act as metallizing nodes 50 when exposed at the external surface. Metal tube 25 may comprise a metal such as chromium, cobalt, gold, nickel, niobium, platinum, silver, stainless steel, tantalum, titanium, zirconium, or alloys and/or oxides thereof. Use of metal(s) having a relatively high x-ray frequency damping coefficient can enhance visualization of catheter 10 under fixed x-ray imaging or fluoroscopy, with attendant reduced requirements for radiopaque fillers in hollow core 20 or outer jacket 30.
Metal tube 25 may also have a pattern of apertures 55, through which hollow core 20 and outer jacket 30 may be adhered to each other, as shown in
In
In
A method of making catheter 10 is illustrated schematically in
If it is desired to vary the pattern of apertures 55 along the length of catheter 10, then the pattern formed in metal tube 25 can be repeated or reversed every length L, as shown in
Optionally, distal segment 34 may be formed in outer jacket 30 by removing a first jacket material of about the length of segment 34, then refilling the void with a second, different, e.g. softer, material. In a first alternative method of making catheter 10, outer jacket 30 can be applied after metal tube 25 has been formed around hollow core 20, and after multiple catheter sub-assemblies have been cut to length L. Unlike braided reinforcement layers, metal tube 25 will not tend to expand or unravel when it has been cut. In the first alternative method, catheter sub-assemblies can be fed individually through an extrusion “wire-head,” or a pre-extruded tube can be radially compressed around the catheter sub-assembly by using a heat-shrink method. Additionally, distal segment 34 and/or other segments can be formed in catheter 10 by shrink-fitting different pre-extruded tubes around the catheter sub-assembly according to methods known by those of skill in the field of catheters.
According to a second alternative method, each catheter 10 is fabricated individually from the beginning, instead of using the above reel-to-reel method. This second alternative method is especially useful when hollow core 20 is made from a paste extrudable polymer such as PTFE, which has a finite extrudable length that is unsuitable for reel-to-reel catheter manufacturing. The processing steps and the order of operations are the same as those discussed above, except that any cutting step would only be required to trim individual sub-assemblies to length L.
While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3998602 | Horowitz et al. | Dec 1976 | A |
| 4082621 | Spiliotis et al. | Apr 1978 | A |
| 4100312 | Lombardo et al. | Jul 1978 | A |
| 4211811 | Bordini et al. | Jul 1980 | A |
| 4374709 | Combs | Feb 1983 | A |
| 4493861 | Sirinyan et al. | Jan 1985 | A |
| 4520046 | McCaskie et al. | May 1985 | A |
| 4547193 | Rydell | Oct 1985 | A |
| 4560445 | Hoover et al. | Dec 1985 | A |
| 4576685 | Goffredo et al. | Mar 1986 | A |
| 4600480 | Coombes et al. | Jul 1986 | A |
| 4663199 | Liebler et al. | May 1987 | A |
| 4748056 | Nuzzi et al. | May 1988 | A |
| 4790831 | Skribiski | Dec 1988 | A |
| 4863442 | DeMello et al. | Sep 1989 | A |
| 4895739 | Bladon | Jan 1990 | A |
| 4952357 | Euteneuer | Aug 1990 | A |
| 5007990 | Bladon | Apr 1991 | A |
| 5101682 | Radisch et al. | Apr 1992 | A |
| 5211803 | Johnson et al. | May 1993 | A |
| 5217440 | Frassica | Jun 1993 | A |
| 5275597 | Higgins et al. | Jan 1994 | A |
| 5407622 | Cleveland et al. | Apr 1995 | A |
| 5573520 | Schwartz et al. | Nov 1996 | A |
| 5605543 | Swanson | Feb 1997 | A |
| 5685961 | Pourrezaei et al. | Nov 1997 | A |
| 5702584 | Goenka et al. | Dec 1997 | A |
| 5725510 | Hartmann et al. | Mar 1998 | A |
| 5725513 | Ju et al. | Mar 1998 | A |
| 5741429 | Donadio, III et al. | Apr 1998 | A |
| 5743876 | Swanson | Apr 1998 | A |
| 5945486 | Vargo et al. | Aug 1999 | A |
| 5951881 | Rogers et al. | Sep 1999 | A |
| 5991650 | Swanson et al. | Nov 1999 | A |
| 6143145 | Copping et al. | Nov 2000 | A |
| 6293311 | Bushi et al. | Sep 2001 | B1 |
| 6605399 | Chowdry et al. | Aug 2003 | B2 |
| 20030082324 | Sogard et al. | May 2003 | A1 |
| 20040103976 | Busshoff et al. | Jun 2004 | A1 |
| Number | Date | Country |
|---|---|---|
| 0155473 | Aug 2001 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20040054349 A1 | Mar 2004 | US |
