Hydrophilically coated flexible wire guide

Abstract: A wire guide comprising an elongate central core (11) and a coil (14) formed of radiopaque material which is positioned substantially concentrically with the elongate central core. The wire guide also comprises a polymer sleeve (12) which encloses the elongated central core. The guide wire further comprises a hydrophilic coating (13) which substantially encloses the polymer sleeve.

Description: This invention relates to wire guides which may be used for placement of catheters. One application for which such wire guides are used is the percutaneous placement of a catheter into the vascular system. The procedure involves penetrating an organ, such as a vein or the like, with a needle. The wire guide is then passed through the needle into the organ. The needle is then withdrawn over the wire guide, leaving the wire guide in place in the organ. A catheter is then slid over the wire guide into the organ and further guided by the wire guide through the organ. Such a wire guide can be used, for example, to position a catheter at difficult to reach locations in or around the heart or the like. Wire guides have heretofore been provided to facilitate the insertion of a catheter into an organ, such as a vein, and further to facilitate the guidance of a catheter through an organ to various locations in a body. Certain prior art wire guides have a coil spring throughout its entire length of the guide and therefore are susceptible to breakage. In addition, use of some prior art wire guides create friction between the coils of the spring and the inner surface of the organ. EP-A-0200430 discloses a wire guide comprising an elongated central core and a coil concentric with the central core and secured to the distal portion of the central core, the proximal portion of the central core being surrounded by a polymer sleeve. US-A-4682607 discloses a wire guide having a polymer coating extending from the proximal end, and a second, hydrophilic polymer coat to provide a smooth surface for insertion into a vessel. In order to overcome the problems referred to above, wire guides were developed having a plastic outside surface. Other wire guides have been developed including a hydrophilic coating on the outside surface in order to reduce friction between the outer surface of the wire guide and the inner surface of the organ and further to reduce the likelihood of breakage of the wire guide while in the organ. As regards prior art wire guides having a hydrophilic coating on their outside surface, such coating extends over the entire proximal portion of the wire guide making it difficult for the operator to grip and control the wire guide. JP 1-135363 disloses in Fig 3 a wire guide without a coil. The wire guide includes a core completely enclosed by a coating of a synthetic resin. A coating of a lubricity imparting agent partially encloses the synthetic resin coating. The wire guide according to the invention comprises: the features according to claim 1. FIG. 1 is a side elevational view partially in cross section of a wire guide incorporating the present invention. FIG. 2 is a cross-sectional view taken along the line 3-3 of FIGS. 1. For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Referring now to FIGS. 1 and 2, there is illustrated a wire guide 20 which may have a diameter ranging from 0.030 to 0.165 cm. (0.012 to 0.065 inches) and a length ranging from 20.0 to 460.0 centimeters. Wire guide 10 includes a flexible elongated central core 11 having a uniform thickness at its proximal portion 11a and tapered at its distal portion 11b. The length of the taper at distal portion of elongate central core 11b can vary from 1.0 to 30.0 centimeters, however, such taper length is typically 10.0 to 15.0 centimeters. The elongated central core 11 also includes a proximal end 11c and a distal end 11d. The central core 11 may be formed of any suitable metal, however, it is preferred to construct elongate central core 11 from a nickel titanium alloy such as Nitinol. When Nitinol is used, the diameter of the elongate central core 11 should be very near the diameter of wire guide 20. Nitinol does not have as great a stiffness or tensile strength as other materials such as stainless steel. Therefore, in order to overcome the resulting loss in stiffness, a much larger diameter Nitinol elongate central core is used. The distal portion 11b of elongate central core is affixed to an elongate coil 14 at either its proximal portion 14a or its distal portion 14b or both. Such affixation may be achieved by welding, soldering or glue bonding. Elongate coil 14 may be made of platinum in order to give wire guide 20 extremely good radiopacity (better than stainless steel) and a soft, floppy distal portion. The coil 14 may range in length from 1.0 to 15.0 centimeters, however, its length is typically 2.0 to 3.0 centimeters. Also affixed to distal portion of elongate central core 11b is a safety ribbon wire 15. The safety ribbon wire 15 may be made of a suitable material such as stainless steel. Safety ribbon wire 15 has a proximal portion 15a and a distal portion 15b. The safety ribbon wire 15 may be affixed to elongate central core 11 by welding, soldering or glue bonding the above two members together. One possibility is to affix the distal portion of elongate member 11b to the proximal portion of safety ribbon wire 15a. A thin polymer sleeve 22 completely encloses proximal portion of elongate central core 11a and proximal end of elongate central core 11c. The resulting outer diameter of polymer sleeve 12 positioned on top of elongate central core 11 is substantially the same as the diameter of wire guide 20. Polymer sleeve 22 has a proximal portion 22a and a distal portion 22b. Distal portion of polymer sleeve 22b partially encloses distal portion of elongate central core 11b. In addition, distal portion of polymer sleeve 22b partially covers the proximal portion 14a of the coil and the proximal portion 15a of safety ribbon wire. Polymer sleeve 22 can be formed from any suitable material such as polyurethane. The polymer sleeve 22 creates a good base for a hydrophilic coating 23 and gives wire guide 20 a good appearance and surface finish. The hydrophilic coating 23 includes a proximal portion 23a and a distal portion 23b. The distal portion of hydrophilic coating 23b encloses distal portion of polymer sleeve 22b and partially encloses distal portion of elongate central core 11b. In addition, distal portion of hydrophilic coating 23b partially covers the proximal portion of the coil 14a and proximal portion of safety ribbon wire 15a. The hydrophilic coating 23 makes wire guide 20 extremely slick and allows it to be easily maneuvered through tortuous areas. A rounded metallic protrusion 16 is disposed on the distal extremity of wire guide 20. The metallic protrusion 16 can be affixed to distal portion of safety ribbon wire 15b. Such protrusion is formed by a weld or solder. The proximal portion of hydrophilic coating 23a proximally terminates so as not to cover the extreme proximal portion of polymer sleeve 22a. The non-hydrophilically coated proximal portion of polymer sleeve 22a may vary in length from 10.0 to 30.0 centimeters. The benefit of not coating the extreme proximal portion of wire guide 20 with the hydrophilic material is to facilitate better gripping and consequently greater control of wire guide 20 during its use. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the scope of the invention are desired to be protected.

Claims: A wire guide (20) comprising: a elongated central core (11) having a proximal portion (11a) and distal portion (11b), the central core further having a proximal end (11c) and distal end (11d); a coil (14) positioned substantially concentrically with the central core and secured to the distal portion of the central core, the coil having a proximal portion (14a) and distal portion (14b); a polymer sleeve (22) having a proximal portion (22a) and distal portion (22b), the polymer sleeve completely enclosing the proximal portion of the central core, a hydrophilic coating (23) having a proximal portion (23a) and distal portion (23b), the polymer sleeve distally terminating at the proximal portion of the coil the polymer sleeve thereby partially covering the proximal portion of the coil and, wherein the hydrophilic coating (23) partially encloses the polymer sleeve (22) and proximally terminates at a point distal relative to the proximal end (22a) of the polymer sleeve. The wire guide of either preceding claim wherein the central core (11) is made of a nickel titanium alloy. The wire guide of claim 1 wherein the coil (14) is made of platinum. The wire guide of any preceding claim wherein the diameter of the central core (11) is very near the diameter of the wire guide (20). The wire guide of any preceding claim wherein the proximal portion (11a) of the central core (11) is uniform in diameter and the distal portion (11b) of the central core (11) is tapered.

Inventors: BATES BRIAN L, OSBORNE THOMAS A, BATES, BRIAN L., OSBORNE, THOMAS A.
Applicants: COOK INC, COOK INCORPORATED
Application year: 1990
Main classification: A61M25
IPC codes: A61M25, A61L29