Patent Application
20100049136
The present invention generally relates to a guide wire allowing for reversal of direction of catheterization of a body lumen and to a method of use thereof.
Numerous medical procedures involve the introduction of a catheter or a similar device into a lumen in the body. Structures which can be accessed by catheterization include the blood vessels, the bowel and digestive tract, the bile ducts, the urinary tract and several others. Known catheterization procedures include the positioning and inflation of balloons for opening a constricted vessel, the positioning and expansion of stents for maintaining an open lumen in a constricted vessel, the intravenous administration of nutrient fluids, the delivery of whole blood or blood products, the sampling of blood and the administration of chemotherapeutic agents or other drugs.
The first step in the performance of such procedures is the establishment of a site through the skin by which access is had to the lumen. A guide wire is introduced into the lumen and the catheter advanced over the guide wire into the lumen in one direction or another to a desired location. If this direction is opposite to the direction of fluid flow in the vessel or other structure, it is referred to as the “retrograde” direction. On the other hand, if this direction is the same as the direction of fluid flow in the vessel, it is referred to as the “antegrade” direction. By way of example, catheterization of the femoral artery, axillary artery or brachial artery for access to the vessels of the abdomen or thorax is carried out by advancement of the catheter in the retrograde direction.
It is sometimes the case that a lumen cannot be catheterized in the required direction. For example, accessing the superficial femoral artery of critical limb ischemia patients with an ipsi-lateral approach is difficult if the patients are morbidly obese. Accessing using a needle angling downward is difficult because of the obesity. In such cases, it is advantageous to access with the needle upward and deliver the guide wire in this configuration. However, it has generally been found to be very difficult, sometimes even impossible, to reverse the direction of catheter advancement through the initial access site.
It should thus be clear that it would be highly desirable to have an apparatus for reversing the direction of catheterization within a patient, either retrograde to antegrade, or antegrade to retrograde. It would also be highly desirable to have such an apparatus that is relatively simple and reliable in construction and use, and which is relatively low in cost, at least in comparison to the costs and risks incurred in establishing a second access site.
One aspect provides a guide wire including a first elongated member having a proximal end and a distal end. A second elongated member is attached to the distal end of the first elongated member and to a spring element joining the distal end of the second elongated member to a third elongated member. The third elongated member is movable about the spring element between a first position folded upon the second elongated member and a second position extending distally from the second elongated member.
In one embodiment, the second elongated member has a maximum cross sectional dimension that is less than a maximum cross sectional dimension of the first elongated member. In another embodiment, the second elongated member and the third elongated member each have a maximum cross sectional dimension that is equal to or less than a maximum cross sectional dimension of the first elongated member.
In yet another embodiment, the guide wire comprises a self-expanding nickel titanium alloy. In another embodiment, the third elongated member is spring-biased to extend distally from the second elongated member.
In one embodiment, the maximum cross sectional dimension of the first elongated member is between 0.04 mm and 0.02 mm. In yet another embodiment, the maximum cross sectional dimension of the second elongated member is between 0.02 mm and 0.01 mm.
Another aspect provides a method of reversing direction of catheterization of a guide wire into a body lumen of a patient. The method includes inserting a needle into the lumen in a first direction and inserting the distal end of a guide wire of the present embodiments into the needle and into the lumen. During insertion, the third elongated member is folded upon the second elongated member.
The needle is removed and, in certain embodiments, an inducer sheath is advanced over the guide wire until the inducer sheath is positioned over the first elongated member. The first elongated member is rotated whereby the third elongated member is moved about the spring element to a position extending distally from the second elongated member.
a)-1(b) are illustrations of one embodiment of a guide wire.
a)-(c) are illustrations of three embodiments of a guide wire.
a)-(e) are schematic illustrations of a method of reversing the direction of a guide wire within a body lumen.
As used herein, the term “proximal” refers to that portion of the device closest to a physician when placing the device in the patient lumen, and the term “distal” refers to that portion of the device closest to the end inserted into the patient's body lumen. The terms “antegrade” and “retrograde” refer to directions relative to the direction of fluid flow within the body lumen. The antegrade refers to the direction of fluid flow within the body lumen.
Referring now to
a)-(c) illustrate alternative embodiments of spring element 40.
Second elongated member 30 may be an extension of first elongated member 20 formed by reducing the cross section of a portion of first elongated member 20. Such an embodiment is illustrated in
Guide wire 10 or portions thereof may be formed of materials such as stainless steel, tantalum, nickel-titanium alloys, such a NITINOL®, gold, silver, tungsten, platinum, cobalt-chromium alloys and iridium, all of which are commercially available metals or alloys. Spring element 40 may be formed of similar materials. In one embodiment, spring element 40 is formed from a self-expanding nickel-titanium alloy, such a NITINOL®.
In one embodiment, the maximum cross sectional dimension of first elongated member 20 is such that guide wire 10 may be introduced into a body lumen through a hypodermic needle, for example, an 18 gauge hypodermic needle. In one embodiment, the maximum cross sectional dimension of first elongated member 20 is between 0.04 mm and 0.02 mm. In another embodiment, the maximum cross sectional dimension of first elongated member 20 is between 0.035 mm and 0.025 mm.
In other embodiments, the maximum cross sectional dimension of second elongated member 30 is less than the maximum cross sectional dimension of first elongated member 20. In one embodiment, the maximum cross sectional dimension of second elongated member 30 is half or less than half the maximum cross sectional dimension of first elongated member 20. In another embodiment, the maximum cross sectional dimension of second elongated member 30 is between 0.02 mm and 0.01 mm. In yet another embodiment, the maximum cross sectional dimension of second elongated member 30 is between 0.017 mm and 0.013 mm.
In another embodiment, the maximum cross sectional dimension of third elongated member 50 is approximately the same as that of second elongated member 30. In yet another embodiment, the maximum cross sectional dimension of second elongated member 30 and the maximum cross sectional dimension of third elongated member 50 are both half or less than half the maximum cross sectional dimension of first elongated member 20.
In another embodiment, the combined maximum cross sectional dimension of the second elongated member 30 and the third elongated member third elongated member 50 is equal to or less than the maximum cross sectional dimension of first elongated member 20.
The lengths of second elongated member 30 and third elongated member 50 are chosen to allow guide wire 10 to be introduced into the body lumen such that the end of third elongated member 50 attached to spring element 40 is delivered beyond the distal end of the delivery needle and is hence free to move away from a folded position against second elongated member 30. In one embodiment, second elongated member 20 is between 3.5 cm and 4.5 cm in length. In another embodiment, second elongated member 20 is approximately 4.1 cm in length. In yet another embodiment, third elongated member 50 is between 2.5 cm and 3.5 cm in length. In another embodiment, third elongated member is approximately 3.0 cm in length.
In one embodiment, third elongated member 50 is spring-biased at spring element 40 so that second elongated member 30 extends away from second elongated member 30 when free to do so, for example, then third elongated member 50 is inserted into a body lumen beyond the distal end of a delivery needle. In such embodiments, the spring strength or stiffness of spring element 40 is chosen so that although third elongated member 50 moves away from second elongated member 30 when not constrained, it does not do so with sufficient force to damage the wall of the body lumen. Selection of appropriate spring strength may be achieved to methods known to those skilled in the art. In one embodiment, the end of third elongated member 50 that is not attached at spring element 40 is blunt and/or includes a cap to prevent or reduce damage to the wall of the body lumen.
The guide wire may have typical guide wire dimensions. The guide wire length may generally be about 90 to about 300 cm, and for use within a patient's coronary system available guide wires are typically about 180 cm in length.
In one embodiment, the body lumen is a vascular vessel. For example, the device may be used to reverse direction of catheterization of the femoral artery. Accessing the superficial femoral artery of critical limb ischemia patients with an ipsi-lateral approach is difficult if the patients are morbidly obese. Accessing using a needle angling downward is difficult because of the obesity. In such cases, it is advantageous to access with the needle upward and deliver the guide wire in this configuration. In other embodiments, the body lumen is, for example, the bowel and digestive tract, the bile ducts or the urinary tract. However, the devices and methods of the present embodiments may be used to reverse the direction of the guide wire within other body lumens.
a)-(e) illustrate a procedure for reversing the direction of the guide wire within a body lumen, for example, a vascular vessel.
Needle 420 is removed leaving guide wire 10 in place in vessel 410, as is illustrated in
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.
