EELLS, Robert, M. (7552 S. Mt. Zion Rd, Bloomington, IN, 47403, US)
| CLAIMS 1. A wire guide comprising: an elongate core wire having a precurved distal end; a flexible outer coil slidably disposed about the elongated core wire, the flexible outer coil having a distal end portion and a remaining proximal portion, the remaining proximal portion extending along a longitudinal axis defined by the elongate core; wherein the precurved distal end is configured to direct the distal end portion of the coil along a different direction than that of the longitudinal axis. 2. The wire guide of claim 1 , wherein the precurved distal end comprises an arc between 90 and 180 degrees. 3. The wire guide of claim 1 or 2, wherein the distal end of the outer coil includes a distal end member comprising a radiopaque material. 4. The wire guide of claim 3, wherein the outer coil further comprises a safety wire, the safety wire having a distal safety end and a proximal safety end, the distal safety end attached to the distal end member and the proximal safety end attached to the proximal portion of the outer coil. 5. The wire guide of claim 1 , 2, 3 or 4, wherein the elongate core wire tapers in thickness along a portion of its length adjacent the precurved distal end. 6. The wire guide of claims 1 , 2, 3, 4 or 5, wherein the flexible outer coil further comprises a relaxed distal end portion. 7. A method of using the wire guide of one of claims 1 through 6 comprising: providing the wire guide of one of claims 1-6; providing an introducing device; inserting the wire guide into a passage in the introducing device, with the introducing device oriented in a first direction; positioning the precurved distal end and the distal end of the flexible outer coil beyond a distal end of the introducing device such that the precurved distal end and distal end of the flexible outer coil are oriented in a second direction; and advancing the outer flexible coil over the precurved end of the elongate core so that a distal end of the coil is advanced along the second direction. 8. The method of claim 7, wherein the introducing device comprises an endoscope. 9. The method of claim 7, wherein the introducing device comprises an introducer. 10. The method of claim 7, 8 or 9, wherein the second direction is in the range of 90 to 180 degrees relative to the first direction. 11. The method of claim 7, 8, 9 or 10, further comprising advancing the elongate core and outer flexible coil together a first distance beyond the distal end of the introducing device before advancing the outer flexible coil over the precurved end of the elongate core. |
TECHNICAL FIELD
[0001] The present invention generally relates to medical devices and specifically to a wire guide for percutaneous placement of a medical device within a body cavity. Or more specifically, the present invention is directed to a wire guide that may be inserted in a first direction and then advanced in a second direction.
BACKGROUND
[0002] Wire guides are commonly used in vascular procedures, such as angioplasty procedures, diagnostic and interventional procedures, percutaneous access procedures, or radiological and neuroradiological procedures in general, to introduce a wide variety of medical devices into the vascular system. For example, wire guides are used for advancing intraluminal devices such as stent delivery catheters, balloon dilation catheters, atherectomy catheters, and the like within body lumens. Typically, the wire guide is positioned inside the inner lumen of an introducer catheter. The wire guide is advanced out of the distal end of the introducer catheter into the patient until the distal end of the wire guide reaches the location where the interventional procedure is to be performed. After the wire guide is inserted, another device such as a stent delivery catheter is advanced over the previously introduced wire guide and into the patient until the stent delivery catheter is in the desired location. After the stent has been delivered, the stent delivery catheter can then be removed from a patient by retracting the stent delivery catheter back over the wire guide.
[0003] Typically, wire guides are introduced percutaneously by means of an introducer, for example through an introducer catheter, needle or dilatation catheter. The introducer is generally oriented at least partially in the direction in which the wire guide is to be placed. Once positioned, the wire guide is advanced through the introducer and positioned adjacent to the desired location for treatment. However, in some instances it is desirable to direct a wire guide in a direction opposite to the initial direction of entry of the introducer. In other instances, it is difficult or impossible to orient the introducer in the desired direction.
[0004] Some devices have previously been provided which allow a physician to employ a guide wire in a first direction via an introducer, and subsequently, redirect the guide wire and introducer in the opposite direction. Such prior art retrograde-antegrade wire guides allow the physician to reverse the direction of an introducer catheter from a first direction to a second direction, and then remove the retrograde-antegrade wire guide and replace it with a conventional wire guide for use in subsequent steps in the treatment procedure. However, these retrograde-antegrade wire guides require the performance of several steps to successfully reorient the introducer before the retrograde-antegrade wire guide can be removed and replaced with another wire guide, which increases the duration and complexity of the treatment procedure.
[0005] Furthermore, in some instances, treatment may be required in locations in which access to a viable entry point is only available in a direction facing away from the desired treatment location. For example, with conditions in vessels in the lower portion of a patient's leg, a percutaneous entry may be available only in the direction oriented toward the abdomen. Access in the desired direction within a given femoral artery, for example, may be further limited in instances in which the patient is overweight or obese. In the past, physicians often treated conditions in the lower portions of the legs by inserting a wire guide into the femoral artery of one leg, directing it into the iliac artery, and then directing it down into the femoral artery of the other leg to be treated. Disadvantageously, such treatment requires a longer wire guide, and also may cause trauma to both femoral arteries as well as the iliac artery. Therefore, a need exists for a method of using a wire guide and a wire guide that may be introduced through an introducer directed in a first direction while allowing the wire guide to be directed in a second, substantially different direction.
BRIEF SUMMARY
[0006] The present invention is directed to and discloses tools, methods and systems for using a wire guide. The tools, methods and systems include a wire guide that may be inserted in a first direction and then subsequently advanced in a second direction.
[0007] Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description and the figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 shows an embodiment of an illustrative core having a pre- curved end for a wire guide according to the invention.
[0009] Figure 2 shows an embodiment of an illustrative flexible outer coil for a wire guide according to the invention.
[0010] Figure 3 shows an embodiment of a wire guide having a flexible outer coil disposed about a core having a pre-curved end according to the invention.
[0011] Figure 4 shows a cross-sectional view of the wire guide of Figure 3 as taken along line A-A.
[0012] Figure 5 depicts an embodiment of the wire guide shown in Figure 3 having the flexible outer coil advanced along the core.
[0013] Figure 6 shows an embodiment of a wire guide having a flexible outer coil disposed about a core having a pre-curved end being inserted into a vessel through an introducer according to the invention.
[0014] Figure 7 shows an embodiment of a wire guide having a flexible outer coil disposed about a core having a pre-curved end, wherein the wire - A -
guide that has been inserted into the body and directed to a branch in the vasculature according to the invention.
DETAILED DESCRIPTION
[0015] In accordance with the invention, a wire guide includes a flexible outer coil disposed about a core having a pre-curved end such that the outer coil may be advanced over the core into a patient's body cavity. As used herein, the term "proximal" refers to a portion of the wire guide closest to a physician when placing a wire guide in the patient, and the term "distal" refers to a portion of the wire guide closest to the end that is or is to be inserted into the patient.
[0016] Figure 1 shows an embodiment of a core 11 for use in a wire guide according to the invention. The core 11 includes a proximal core end 13 that is kept outside the patient's body and a distal core tip 19 capable of being advanced into a patient's vascular system. An elongated shaft 15 extends from the proximal core end 13 towards the distal core tip 19. The elongated shaft 15 may carry a handle near the proximal core end 13 to allow the physician to grasp the core 11. The handle may be releasably secured to the elongated shaft 15. The elongated shaft 15 has a pre-curved end 17 near the distal core tip 19. In the embodiment shown in Fig. 1 , the pre-curved end 17 is bent or curved through an angle of approximately 180 degrees relative to the longitudinal axis of the elongated shaft 15. However, those skilled in the art will understand that it may be desirable for the pre-curved end 17 to be bent at other angles depending upon the intended use of the wire guide, including angles in the range from approximately zero degrees to approximately 180 degrees. For example, the pre-curved end 17 may be bent at an angle approximating the pre-determined takeoff angle of a particular vessel in the vascular system.
[0017] As shown in figure 1 , the core 11 may include one or more tapered sections near the distal core tip 19. For example, the core may be tapered inward along a portion of its length corresponding to the pre-curved end 17 to impart an increasing degree of flexibility to core 11 near the distal core tip 19. The tapered sections may have cross-sectional areas that diminish gradually or stepwise as the distal core tip 19 is approached. The rate of taper and the starting point for the tapering may be modified, and in some instances configured to help enable smaller diameter curved ends. [0018] The core 11 is formed from a suitable metal material such as medical grade stainless steel or a superelastic alloy such as Nitinol. It will be appreciated that conventional drawing techniques can be used to manufacture the core 11 , for example, as a wire of constant diameter. The wire can be centerless ground to provide the core 11 with a decreasing cross- sectional area as the distal core tip 19 is approached. Alternatively, the wire for the core 11 can be drawn in stages to provide a cross-sectional area that diminishes stepwise at various distances as the distal core tip 19 is approached. The bend or arc in the pre-curved end 17 can be formed by an annealing method, e.g., maintaining the core 11 in the desired final shape while subjecting it to extreme heat for a prescribed period of time, or a cold working method, e.g., mechanically stressing and plastically deforming the core while in its austenitic state to create at least a partial localized zone of martensite. The nitinol core can be made relatively thin while still retaining the preformed bend and the requisite stiffness. Other possible materials for the core include elastic biocompatible metals such as stainless steel, titanium, or tantalum. Regardless, the core disclosed herein is not limited to these materials or manufacturing techniques and may, in some embodiments, be made of other materials including plastics or other metals and by other manufacturing techniques.
[0019] Figure 2 depicts an embodiment of a flexible outer coil 21 for use in a wire guide according to the invention. The outer coil 21 includes a proximal coil end 23, a middle portion 25, a relaxed distal end portion 27 and a distal coil tip 29. The outer coil 21 comprises a plurality of coiled loops made of round wire or other wires having suitable shapes. The outer coil 21 may be formed from linear elastic materials, such as stainless steel, titanium, tantalum or superelastic alloys, such as Nitinol.
[0020] At the relaxed distal end portion 27, the pitch angle of the outer coil 21 , i.e., the included angle between the longitudinal axis of the outer coil 21 and the coiled loops, preferably is less than 90 degrees. In other words, the coiled loops preferably are oriented relative to the longitudinal axis of the outer coil 21 such that one half of each coiled loop is disposed closer to the distal coil tip 29 than the other half. More preferably, as shown in Figure 2, the pitch angle of the outer coil 21 at the relaxed distal end portion 27 is selected such that the distance parallel to the longitudinal axis of the outer coil 21 between the top and bottom of each coiled loop is approximately equal to the diameter of the wire forming the coiled loops. The coiled loops of the relaxed distal end portion 27 may also be axially spaced apart from one another, which may desirably reduce stresses in the outer coil 21 when it is assembled around a core and stored prior to use. However, those skilled in the art will understand that the relaxed distal end portion 27 can have other dimensions and is not limited to the materials disclosed herein, and that other materials may be used.
[0021] In the embodiment shown in Figure 2, the distal coil tip 29 ends distally at a distal end member 31 , which comprises a member having an atraumatic front end termination, such as a rounded front or a front of very flexible material or very flexible configuration. The distal end member 31 is attached to the distal coil tip 29 of the outer coil 21 in a suitable manner as is known in the art, for example, by welding or soldering. In one embodiment, the distal end member may be a soldier ball. Alternatively, the distal end member 31 may be a sphere made from a flexible material that is laser welded onto the distal coil tip 29 or a soft coil of radiopaque materials such as gold or platinum. [0022] A safety wire 33 is placed within a central lumen 35 of the outer coil 21. The safety wire 33 has a distal wire end 37 and a proximal wire end 39. The distal wire end 37 of the safety wire 33 attaches to the distal end member 31 , while the proximal wire end 39 of the safety wire 33 attaches to the outer coil 21 , preferably at some point away from the distal coil end 29. The safety wire 33 helps prevent the distal end member 31 from becoming dislodged from the outer coil 21 during use and being lost into the vasculature of the patient. Furthermore, the safety wire 33 may help prevent the outer coil 21 from becoming elongated during use. In a preferred embodiment, the safety wire is made from a ribbon wire, as shown in the cross-section of an embodiment of the guide wire shown in Figure 4. However, those skilled in the art understand that the safety wire is not limited to ribbon wire, and could, for example, be made of round wire or other wires having other shapes. The safety wire 33 may be made from any number of materials, including stainless steel and superelastic materials such as Nitinol. However, the safety wire is not limited to these materials and may, for example, be made from other metal or plastic materials.
[0023] Figures 3 and 4 depict an embodiment of a wire guide 41 having the outer coil 21 disposed about the core 11. In use, the core 11 is first inserted into the lumen 35 of the outer coil 21 such that the relaxed distal end portion 27 of the outer coil 21 is disposed about the curved portion 17 of the core 11. The safety wire also is disposed in the lumen 35. As shown in Figure 3, the outer coil 21 has not yet been advanced relative to the core 11 and therefore the distal coil end 29 is adjacent to the distal core tip 19 of the core 11. At the proximal guide wire end 43, the proximal core end 13 extends out beyond the proximal coil end 23. As shown in this embodiment, the safety wire 33 may be sufficiently long so that its proximal end is roughly coincident with the proximal coil end 23. However, as noted above, this relationship between the safety wire 33 and outer coil 21 is not necessary. [0024] Figure 5 shows the wire guide 41 wherein the outer coil 21 has been advanced relative to the core 11 a distance 45 in a direction 47 roughly opposite to the initial direction of advancement 49 of the coil. As noted above, different bend or arc angles may be used for the core 11 , and therefore in other embodiments of the wire guide the direction of advancement may not be substantially opposite to the initial direction of advancement 49.
[0025] To advance the outer coil 21 of the wire guide 41 as shown in Figure 5, the physician may grasp the proximal core end 13 while pushing the proximal coil end 23 in the initial direction 49. As the physician advances the proximal coil end 23 away from the proximal core end 13, the distal coil end 29 is advanced past the distal core tip19 into the vasculature of the patient. In this manner, during use, the distal core tip 19 remains generally in the same location in the patient while the distal coil end 29 is advanced to the treatment location.
[0026] It should be understood that the physician may grasp the core 11 and outer coil 21 directly, or that a handle or connector may be attached to the outer coil and or core. While the use of a handle may improve the gripability of the guide wire components, it may decrease the tactile feedback to the physician, and therefore use of a handle is a matter of preference left to physicians.
[0027] Furthermore, it should be understood that additional modifications may be made to the device disclosed herein. For instance, in some embodiments it may be desirable to coat the outer coil and/or core with coatings to reduce friction. These coatings generally will comprise polymeric materials, including, in some instances, fluoropolymers, however other materials may be used. Additionally, it may be desirable to include radiopaque materials in the outer coil of the guide wire to assist with placement. As noted above, the safety tip may be made from a radiopaque material, however other portions of the guide wire, and particularly the outer coil, may include radiopaque materials.
[0028] Figure 6 illustrates an embodiment of a method of use of a guide wire according to the invention. In this method of use, an introducer 51 is inserted into a body cavity 55 of a patient through a percutaneous entry 53. An embodiment of the wire guide 41 is then inserted through the introducer 51 into the body cavity 55 of the patient. Alternatively, the wire guide may be preloaded into the introducer. The introducer 51 may, for example, consist of an introducer catheter, a needle or a dilatation catheter. However, those skilled in the art understand that other devices may be used to introduce the wire guide 41 into the patient's body cavity. For example, the wire guide may be introduced through the working channel of an endoscope that has been introduced into the patient via a natural passageway of the patient, such as the esophagus or colon. Additionally, it should be understood that the wire guide 41 may be introduced into the patient subsequent to the placement of a standard wire guide if it becomes necessary to change the advancement orientation of the wire guide. In Figure 6, the body cavity 55 is depicted as a blood vessel. It should be understood that the term "vessel" is used herein to refer to a part of the vascular system such as an artery or vein. [0029] As shown in figure 6, and with further reference to Figure 3, the physician positions the curved end of the wire guide through the introducer 51 such that the pre-curved end 17 and distal core tip 19 of the core are located inside the body cavity 55 and directed in a different direction of advancement 57. In the case of figure 6, the direction of advancement 57 is substantially opposite to the direction of blood flow (indicated by arrow 59). Once the guide wire 41 , including the core 11 , is inserted so that the pre-curved end 17 and distal core tip 19 of the core are positioned in the body cavity 55, the physician may advance the outer coil 21 over the core 11. To advance the outer coil 21 , the physician grasps in one hand the shaft 15 of the core 11 near the proximal core end 13, and then grasps the outer coil 21 near its proximal coil end 23 and pushes the proximal coil end 23 in the direction of advancement 57. The physician continues to advance the outer coil 21 over the core 11 until the distal coil tip 29 is placed proximal to or just past the location to be treated.
[0030] In one application, the wire guide 41 is inserted through the introducer 51 at a percutaneous entry 53 into the femoral artery of a patient in order to treat a lesion located in the patient's lower leg (that is, nearer the patient's foot than the percutaneous entry 53). Once the wire guide 41 is inserted so that the pre-curved end 17 and distal core tip 19 of the core are positioned in the femoral artery, the outer coil 21 is advanced over the core 11. The physician advances the outer coil 21 until the distal coil tip 29 is positioned proximal to or beyond the lesion so that a treatment device may be run over the outer coil 21 proximal to the lesion in order to apply a treatment. For instance, a catheter may be run over the outer coil 21 to place a stent in a stenosis in the patient's lower leg.
[0031] In an alternate method of use illustrated in figure 7, an introducer 51 is inserted into a body cavity 55 through a percutaneous entry 53. A wire guide 41 is then inserted into the body cavity 55 through the introducer 51. The wire guide 41 is then advanced as a unit (that is, both the core 11 and outer coil 21 are moved in unison) to a point within the body cavity 55. Typically, as shown in figure 7, the wire guide 41 would be moved in unison until the pre-curved end 17 and distal core tip 19 of the core 11 and the distal coil tip 29 are adjacent a branching 61 within the body cavity 55. Once positioned at the branching 61 , the outer coil 21 is advanced over the core 11 in a direction of advancement 63. As depicted in figure 7, this direction of advancement 63 is substantially opposite to a positioning direction 65. Those skilled in the art will understand that the advancement direction may be oriented at any angle with respect to the positioning direction. [0032] With those embodiments of the wire guide that include a radiopaque safety tip or radiopaque materials, it may be desirable to obtain images of the wire guide and the radiopaque materials to verify that the wire guide is placed at a desired treatment location. The positioning of the wire guide may be verified by taking images, such as x-rays, showing that the radiopaque material or safety tip in such a position that the physician can be certain that the wire guide extends far enough for the desired treatment device to be positioned at the site to be treated.
[0033] Although the embodiments of the apparatus and method described above have been illustrated for use in percutaneous medical procedures, it should be understood that the present invention may be suitable for non- percutaneous procedures. For example, such a wire guide may be used with procedures performed using an endoscope.
[0034] Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope and spirit of the invention as defined by the claims that follow. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.