Patent Application
20090275862
1. Field of the Invention
The present invention relates to medical devices. More particularly, the invention relates to guidewires and a method for making guidewires.
2. Background
Often elongated, flexible guidewires are used to gain access to specific inner areas of the body. The guidewires may enter the body through a small opening and travel to parts of the body through body channels. For example, guidewires may be passed through the body via peripheral blood vessels, gastrointestinal tract, or the urinary tract. Guidewires are commercially available and are currently used in cardiology, gastroenterology, urology, and radiology. Once in place at a desired location in the body, guidewires are commonly used as guides for the introduction of additional medical instruments, e.g. catheters.
To assist in advancing a guidewire through a predetermined body vessel, such as an artery or other channel, the guidewire typically includes a generally flexible body portion, which is resistant to kinking, and a forward end portion of increased flexibility. The end portion or distal tip portion often terminates in a smoothly rounded tip. The body portion may include a core wire of stainless steel or other metal. The core wire is appropriately dimensioned in cross-section to provide a controlled degree of flexibility to the body portion. In order to provide greater flexibility to the guidewire at its distal end, the forward end of the core wire may include a section of lesser diameter and hence, of greater flexibility. Typically, around this section of lesser diameter a flexible helically wound wire or spring coil is attached via soldering or welding, forming a solder or weld ball at the distal extreme of the guidewire. The ball is then ground to form the smoothly rounded tip made from solder or weld material.
One concern, however, is that the solder or weld balls may not be consistently formed relative to each other when numerous guidewires are produced. Moreover, with the increasing number of different medical procedures, various tip configurations may be also desirable. Some of these tip configurations may have shapes (e.g. narrow and/or more intricate cross-sections) which require more exact machining and/or grinding of the ball. If the ball is not consistently formed, grinding material away from the ball to form the tip may locally thin-out and/or weaken the attachment of the tip to the core wire which may also facilitate the tip or pieces of the tip becoming detached from the core wire during the medical procedure. If any of these pieces become detached within the body vessel of the patient, they may become problematic for the patient.
In at least one embodiment of the present invention, a method for making a guidewire is provided. The method comprises removing material from a distal portion of a core wire to define a distal tip. The distal tip extends from a proximal portion of the core wire. The distal tip has a maximum cross-sectional dimension not exceeding a maximum diameter of the proximal portion. A collar having a lumen is positioned adjacent to the distal tip about the proximal portion. Positioning the collar includes advancing the distal tip through the lumen.
In one aspect, the collar is formed exclusively from the core wire.
In another aspect, material is removed from a distal section of the proximal portion to define a recessed portion. The collar is placed about the recessed portion.
Further objects, features, and advantages of the present invention will become apparent from consideration of the following description and the appended claims when taken in connection with the accompanying drawings.
a is a side view of a guidewire in accordance with an embodiment of the present invention;
b is a side view of a portion of a guidewire in accordance with another embodiment of the present invention;
c is a side view of a portion of a guidewire in accordance with yet another embodiment of the present invention;
a is a side view of a guidewire in accordance with an embodiment of the present invention;
b is a cross sectional view of the guidewire depicted in
c is a cross-sectional view of a guidewire in accordance with an embodiment of the present invention;
a is an exploded view of a catheter kit for a body vessel in accordance with one embodiment of the present invention;
b is a side view of the catheter kit in accordance with another embodiment of the present invention; and
Detailed embodiments of the present invention are disclosed herein. It is understood however, that the disclosed embodiments are merely exemplary of the invention and may be embodied in various and alternative forms. The figures are not necessarily to scale; some figures may be configured to show the details of a particular component. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting but merely as a representative basis with the claims and for teaching one skilled in the art to practice the present invention.
Examples of the present invention seek to overcome some of the concerns associated with providing a guidewire for guiding various medical devices through a body vessel or cavity of a patient while minimizing the possibility of the distal tip of the guidewire becoming detached during the medical procedure.
Employing the principles of the present invention is, for example, a guidewire, a method for making the guidewire, and a catheter kit. The guidewire, which is made from the method and is utilized in the kit, has an elongated core wire with a forward end that forms the distal tip of the guide wire. The distal tip is integrally connected to the core wire and is preferably formed exclusively from the core wire. In one example, numerous core wires may be produced (e.g. by pultrusion, extrusion or stamping with precision dies) which are dimensionally consistent relative to each other. Machining or grinding of dimensionally consistent core wires allows for more precise material deletion to form corresponding tips for the core wires. Thus, various tip configurations may be produced without locally thinning-out and/or weakening the attachment of the tip to the core wire, which preferably minimizes the possibility of the tip or pieces of the tip becoming detached from the core wire while being deployed within a body vessel of the patient.
Referring to
Material is removed 102 from the distal portion 14 of the core wire 11 to form a distal tip 16. In at least one embodiment, the distal tip 16 is monolithically formed from the core wire 11. For example, the distal tip 16 may be integrally connected with and formed exclusively from the core wire 11.
As illustrated in
As depicted in
Material may also be removed from the core wire 11 at a distal section 22 of the proximal portion 12 to form a recessed portion 24. The recessed portion 24 has a reduced axial cross-sectional dimension 44 relative to the maximum or base diameter 42 of core wire 11. This reduced dimension 44 may provide the forward end of the core wire 11 with greater flexibility.
Referring to
The collar 30 may be positioned about the proximal portion 12 by advancing the distal tip 16 through a lumen 32 of the collar 30. In one example and as illustrated in
In another example, the collar 30 is shrink tubing 38 which may also be advanced over the tip 16 to be positioned about the proximal portion 12. The shrink tubing 38 may be shrunk or reduced in diameter to fit preferably about the recessed portion 24 and retained thereon by the tip and/or frictional engagement with the core wire 11. The shrink tubing 38 may be shrunk, for example, by applying heat or ultraviolet radiation to facilitate crystallization and/or cross-linking of the tubing material. Compositions and processing for shrink tubings 38 are generally known in the art and any suitable shrink tubing and associated processing to shrink the tubing 38 may be used.
In at least one embodiment, the collar 30 is attached to the core wire 11 to form the guide wire 10. The collar 30 may be bonded to the proximal portion 12 with adhesive. Alternatively, the collar 30 may be attached to the proximal portion with solder or by welding. Other suitable means known to those skilled in the art for attaching a collar 30 to the core wire 11 may also be used. Preferably, attachment of the collar 30 to the core wire 11 does not leave remnants of adhesive, solder or welding material on the tip 16.
The collar 30 may also include a radio pacifier that is detectable by X-ray and/or fluoroscopic visualization. The radio pacifier may be incorporated directly into the material of the collar 30 or coated thereon. Alternatively, the radiopacifier may be included as part of the adhesive, welding material or solder that is used to attach the collar 30 to the core wire 11.
Referring to
The kit 50 further includes the guide wire 10 as discussed in the foregoing paragraphs. The guide wire 10 provides a guide catheter 62 (discussed in more detail below) a path during insertion of the guide catheter 62 within the body vessel 51. The size of the wire guide 10 is based on the inside diameter of the guide catheter 62.
The guide catheter 62 or sheath is typically made from polytetrafluoroethylene (PTFE) and is for percutaneously introducing the microcatheter 52 into a body vessel 51. Of course, any other suitable material may be used without falling beyond the scope or spirit of the present invention. The guide catheter 62 may have a size of between about 4-French to 8-French and allows the microcatheter 52 to be inserted therethrough to a desired location in the body vessel 51. The guide catheter 62 receives the microcatheter 52 and provides stability of the microcatheter 52 at a desired location within the body vessel 51. For example, the guide catheter 52 may stay stationary within a common visceral artery, e.g., a common hepatic artery, and adds stability to the microcatheter 52 as the microcatheter 52 is advanced through the guide catheter 62 to a desired point in a connecting artery, e.g., the left or right hepatic artery.
When the distal end 56 of the microcatheter 52 is at the desired point in the body vessel 51, the medical device may be loaded at the proximal end 54 of the microcatheter 52 and is advanced through the microcatheter 52 for deployment through the distal end 56. In one embodiment, a pushwire 64 is used to mechanically advance or push the medical device through the microcatheter 52. The size of the pushwire 64 used depends on the diameter of the microcatheter 52.
It is to be understood that the catheter kit 50 described above is merely one example of a kit that may be used with the guidewire 10, which is for being passed through a body vessel 51 or cavity. Of course, other kits, assemblies, and systems may be used with the guidewire 10 without falling beyond the scope or spirit of the present invention.
As a person skilled in the art will readily appreciate, the above description is meant as an illustration of the implementation of the principles of this invention. This description is not intended to limit the scope of application of this invention in that the invention is susceptible to modification, variation, and change, without departing from the spirit of this invention, as defined in the following claims.
