Patent Application
20050119615
The present invention is generally related to medical devices, kits, and methods. More specifically, the present invention provides a guidewire system for crossing stenosis, partial occlusions, or total occlusions in a patient's body.
Cardiovascular disease frequently arises from the accumulation of atheromatous material on the inner walls of vascular lumens, particularly arterial lumens of the coronary and other vasculature, resulting in a condition known as atherosclerosis. Atheromatous and other vascular deposits restrict blood flow and can cause ischemia which, in acute cases, can result in myocardial infarction or a heart attack. Atheromatous deposits can have widely varying properties, with some deposits being relatively soft and others being fibrous and/or calcified. In the latter case, the deposits are frequently referred to as plaque. Atherosclerosis occurs naturally as a result of aging, but may also be aggravated by factors such as diet, hypertension, heredity, vascular injury, and the like.
Atherosclerosis can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches which rely on intravascular widening or removal of the atheromatous or other material occluding the blood vessel. Particular catheter-based interventions include angioplasty, atherectomy, laser ablation, stenting, and the like. For the most part, the catheters used for these interventions must be introduced over a guidewire, and the guidewire must be placed across the lesion prior to catheter placement. Initial guidewire placement, however, can be difficult or impossible in tortuous regions of the vasculature. Moreover, it can be equally difficult if the lesion is total or near total, i.e. the lesion occludes the blood vessel lumen to such an extent that the guidewire cannot be advanced across the lesion.
To overcome this difficulty, forward-cutting atherectomy catheters have been proposed. Such catheters usually can have a forwardly disposed blade (U.S. Pat. No. 4,926,858) or rotating burr (U.S. Pat. No. 4,445,509). While effective in some cases, these catheter systems, even when being advanced through the body lumen with a separate guidewire, have great difficulty in traversing through the small and tortuous body lumens of the patients and reaching the target site.
For these reasons, it is desired to provide devices, kits, and methods which can access small, tortuous regions of the vasculature and which can remove atheromatous, thrombotic, and other occluding materials from within blood vessels. In particular, it is desired to provide atherectomy systems which can pass through partial occlusions, total occlusions, stenosis, and be able to macerate blood clots or thrombotic material. It is further desirable that the atherectomy system have the ability to infuse and aspirate fluids before, during, or after crossing the lesion. At least some of these objectives will be met by the devices and methods of the present invention described hereinafter and in the claims.
The present invention provides systems and methods for removing occlusive material and passing through occlusions, stenosis, thrombus, and other material in a body lumen. More particularly, the present invention can be used for passing through stenosis or occlusions in a neuro, cardio, and peripheral body lumens. Generally, the present invention includes an elongate member, such as a hollow guidewire, that is advanced through a body lumen and positioned adjacent the occlusion or stenosis. A tissue removal assembly is positioned at or near a distal tip of the hollow guidewire to create an opening in the occlusion. In exemplary embodiments, the tissue removal assembly comprises a drive shaft having a distal tip that is rotated and advanced from within an axial lumen of the hollow guidewire. Once the guidewire has reached the lesion, the guidewire with the exposed rotating drive shaft may be advanced into the lesion (or the guidewire may be in a fixed position and the drive shaft may be advanced) to create a path forward of the hollow guidewire to form a path in the occlusion or stenosis. To facilitate passing through the occlusion or stenosis, the distal end of the hollow guidewire can be steerable to provide better control of the creation of the path through the occlusion or stenosis. Optionally, the target site can be infused and/or aspirated before, during, and after creation of the path through the occlusion.
The hollow guidewire of the present invention has a flexibility, pushability and torqueability to be advanced through the tortuous blood vessel without the use of a separate guidewire or other guiding element. Additionally, the hollow guidewire may be sized to fit within an axial lumen of a conventional support or access catheter system. The catheter system can be delivered either concurrently with the advancement of the hollow guidewire or after the hollow guidewire or conventional guidewire has reached the target site. The position of the hollow guidewire and catheter system can be maintained and stabilized while the drive shaft is rotated and translated out of the axial lumen of the hollow guidewire. The distal tip of the drive shaft can be deflected, coiled, blunted, flattened, enlarged, twisted, basket shaped, or the like. In some embodiments, to increase the rate of removal of the occlusive material, the distal tip is sharpened or impregnated with an abrasive material such as diamond chips, diamond powder, glass, or the like.
The drive shaft can be a counter-wound guidewire construction or be composed of a composite structure comprising a fine wire around which a coil is wrapped. The counter-wound or composite constructions are more flexible than a single wire drive shaft and can provide a tighter bending radius while still retaining the torque transmitting ability so that it can still operate as a lesion penetration mechanism.
In a specific configuration, the drive shaft has spiral threads or external riflings extending along the shaft. The spirals typically extend from the proximal end of the shaft to a point proximal of the distal tip. As the drive shaft is rotated and axially advanced into the occlusive material (concurrently with the hollow guidewire body or with the hollow guidewire body substantially stationary), the distal tip creates a path through the occlusion and removes the material from the body. The spirals on the shaft act similar to an “Archimedes Screw” and transport the removed material proximally through the axial lumen of the hollow guidewire and prevents the loose atheromatous material from escaping into the blood stream.
Systems and kits of the present invention can include a support system or access system, such as a catheter having a body adapted for intraluminal introduction to the target blood vessel. The dimensions and other physical characteristics of the access system body will vary significantly depending on the body lumen which is to be accessed. In the exemplary case, the body of the support or access system is very flexible and is suitable for introduction over a conventional guidewire or the hollow guidewire of the present invention. The support or access system body can either be for “over-the-wire” introduction or for “rapid exchange,” where the guidewire lumen extends only through a distal portion of the access system body. Optionally, the support or access system can have at least one axial channels extending through the lumen to facilitate infusion and/or aspiration of material from the target site. Support or access system bodies will typically be composed of an organic polymer, such as polyvinylchloride, polyurethanes, polyesters, polytetrafluoroethylenes (PTFE), silicone rubbers, natural rubbers, or the like. Suitable bodies may be formed by extrusion, with one or more lumens that extend axially through the body. For example, the support or access system can be a support catheter, interventional catheter, balloon dilation catheter, atherectomy catheter, rotational catheter, extractional catheter, laser ablation catheter, guiding catheter, stenting catheter, ultrasound catheter, and the like.
In use, the access system can be delivered to the target site over a conventional guidewire. Once the access system has been positioned near the target site, the conventional guidewire can be removed and the elongate member (e.g., hollow guidewire) of the present invention can be advanced through an inner lumen of the access system to the target site. Alternatively, because the elongate member can have the flexibility, pushability, and torqueability to be advanced through the tortuous regions of the vasculature, it is possible to advance the elongate member through the vasculature to the target site without the use of the separate guidewire. In such embodiments, the access system can be advanced over the elongate member to the target site. Once the elongate member has been positioned at the target site, the drive shaft is rotated and advanced into the occlusive material or the entire elongate member may be advanced distally into the occlusion. The rotation of the distal tip creates a path forward of the elongate member. In some embodiments the path created by the distal tip has a path radius which is larger than the radius of the distal end of the elongate member. In other embodiments, the path created by the distal tip has a path radius which is the same size or smaller than the radius of the elongate member.
One exemplary hollow guidewire for crossing an occlusion or stenosis within a body lumen comprises an hollow guidewire body comprising a proximal opening, a distal opening, and an axial lumen extending from the proximal opening to the distal opening. A rotatable drive shaft is disposed within the axial lumen, wherein a distal tip of the rotatable drive shaft is adapted to extend distally through the distal opening in the guidewire body. At least one pull wire extends through the axial lumen and is coupled to a distal end portion of the guidewire body. The pull wire(s) comprise a curved surface that substantially corresponds to a shape of an inner surface of the axial lumen.
In one preferred configuration, the hollow guidewire body is composed of a single, laser edged hypotube. In one configuration, a proximal portion of the hollow guidewire comprises one or more sections that comprise a constant pitch. A distal portion of the hollow guidewire may have at least one section that ha a pitch that decreases in the distal direction so as to increase a flexibility in the distal direction along the distal portion of the guidewire body.
In other configurations, the hollow guidewire body optionally comprises a section that comprises no helical windings and has a solid wall. In other configurations, the distal portion may have a pitch that is constant, or the pitch may increase in the distal direction. In many embodiments, the hollow guidewire body will have at least one section that has a right-handed coils and at least one section that has left handed coils. In preferred configurations, the sections with the right handed coils alternate with the sections that have the left handed coils.
The dimensions of the hollow guidewires of the present invention will vary but the largest radial dimension (e.g., outer diameter) is typically between approximately 0.009 inches and 0.040 inches, preferably between approximately 0.035 inches and approximately 0.009 inches, more preferably between approximately 0.024 inches and 0.009 inches, and most preferably between approximately 0.013 and approximately 0.014 inches. A wall thickness of the hollow guidewires of the present invention is typically between approximately 0.001 inches and approximately 0.004 inches, but as with the other dimensions will vary depending on the desired characteristics of the hollow guidewire. The construction of the hollow guidewire will typically provide a 1:1 torqueability and the hollow guidewire will have the torqueability, pushability, and steerability to be advanced through the body lumen without the need of an additional guidewire or other guiding element.
A distal end portion of the hollow guidewire may comprise a plurality of openings or thinned portions that extend circumferentially or radially about at least a portion of the distal end portion of the guidewire body. A rib or other supporting structure will be disposed between each of the openings so as to provide structural support to the distal end portion. The plurality of openings or thinned portions may be used to increase the flexibility and/or bendability of the distal end portion, such that when the pull wires are actuated, the distal end portion is able to deflect without causing kinking in the distal end portion. The distal end portion may also include one or more radiopaque markers to assist in the fluoroscopic tracking of the hollow guidewire.
The hollow guidewires of the present invention may comprise only a single pull wire. In other embodiments, the hollow guidewire comprises two or more pull wires. The pull wires of the present invention may optionally be coated with Teflon® so as to reduce the friction coefficient of the surface and to reduce twisting of the pull wires. As noted above, the pull wires preferably comprise a curved surface that substantially corresponds to an inner surface of the axial lumen of the hollow guidewire. By providing a surface that substantially corresponds to a shape in the inner surface of the axial lumen, the pull wires are able to move radially outward away from the rotating drive shaft. The increased distance away from the center of the axial lumen provides a greater clearance between the pull wires and the rotating drive shaft, while maintaining a thickness and width of the pull wire.
The pull wires may take on a variety of cross-sectional shapes, but the pull wires typically typically have either a D-shape, crescent shape, or an oval shape. As can be appreciated, other embodiments of the pull wires may have a cross-section that is circular, substantially flattened, substantially rectangular, or the like.
In preferred embodiments, in addition to the curved surface that substantially corresponds to the inner surface of the axial lumen, the pull wires typically comprise a flat surface that is adapted to be adjacent the rotating drive shaft. Since the flat surface of the pull wire will provides only a single point of contact with the rotating drive shaft, there is a reduced friction between the pull wire and the drive shaft and there is a reduced chance that the rotating drive shaft gets tangled with the pull wire.
The rotatable drive shaft of the present invention may be axially movable and rotatable within the axial lumen of the hollow guidewire body. Optionally, the rotatable drive shaft may be coated with Teflon® or other materials to improve the rotation of the drive shaft within the axial lumen. The hollow guidewire may comprise a rotating mechanism, such as a rotary drive motor, to control the rotation of the drive shaft. The rotating mechanism can be coupled to the proximal end of the drive shaft to rotate the drive shaft. Optionally, an actuator may be used to control the axial movement of the drive shaft and/or the rotation of the drive shaft. Activation of the actuator moves the drive shaft proximally and distally within the axial lumen of the hollow guidewire. The hollow guidewire may comprise an additional actuator to control the steering or deflection of a distal portion of the hollow guidewire so as to assist in navigating the hollow guidewire through the body lumen.
The hollow guidewires of the present invention may comprise a removable housing coupled to the proximal portion of the hollow guidewire body. The removable housing may comprise a connector assembly that allows for infusion or aspiration, the actuator(s) (for controlling the rotation, axial movement of the drive shaft and/or steering of the distal end portion of the hollow guidewire body), a rotating member (e.g., drive motor), a control system, and/or a power supply. The removable housing allows for advancement of a catheter system over the hollow guidewire. Once the catheter or other elongate body is advanced over the hollow guidewire, the housing may be reattached so as to allow for actuation of the drive shaft.
In another aspect, the present invention provides a hollow guidewire that comprises a hypotube that comprises a proximal portion and a distal portion. At least a part of the distal portion of the hypotube comprise helical windings formed thereon so that the distal portion of the hypotube is more flexible than the proximal portion. While not described in detail herein, it should be appreciated that in other embodiments, the hollow guidewire may be comprised of a braided polymer, carbon, or other composite materials, and the hollow guidewires of the present invention are not limited to hypotubes.
In such configurations, the proximal portion of the hypotube will have a solid wall or helical windings that have a pitch that is larger than a pitch of the distal portion. Typically, a pitch of the helical windings on the distal portion decreases in the distal direction so that a flexibility of the distal end portion increases in the distal direction. Consequently, the proximal portion is the stiffest, an intermediate portion is less stiff, and the distal end is the most flexible. In other embodiments, the pitch may be constant throughout at least a portion of the distal portion, may increase in the distal direction, the pitch may vary throughout the distal portion, or the like.
The distal portion of the hypotube hollow guidewire may optionally comprise a plurality of ribs and openings or thinned portions that extend circumferentially about at least a portion of the distal end portion of the guidewire body. The distal portion may also comprise one or more radiopaque markers thereon.
Similar to the other embodiments, the hypotube hollow guidewire may comprise one or more pull wires. The pull wires preferably comprise a curved surface that substantially corresponds to an inner surface of the axial lumen of the hypotube hollow guidewire, but other conventional shaped pull wires that don't substantially correspond to the inner surface of the axial lumen may also be used. The pull wire may be coupled to a removable proximal housing that is coupled to the proximal portion of the hypotube hollow guidewire body. A removable housing may be coupled to the hollow guidewire and may comprise a connector assembly that allows for infusion or aspiration, one of more actuators (for controlling the rotation, axial movement of the drive shaft and/or steering of the distal end portion of the hypotube hollow guidewire body), a rotating member (e.g., drive motor), a control system, and/or a power supply.
In a further aspect, the present invention provides a steerable guidewire comprising a hollow guidewire body that comprises a proximal end, a distal end, and an axial lumen that extends to the distal end. At least a portion of a tissue removal assembly is positioned at or near the distal end of the guidewire body. At least one pull wire extends through the axial lumen of the hollow guidewire body and is coupled at or near the distal end of the hollow guidewire body. A proximal force on the pull wire steers the distal end of the hollow guidewire.
The tissue removal assembly may be fixedly or movably disposed at the distal end of the hollow guidewire body. If the tissue removal assembly is movable, the tissue removal assembly may be movable from a first, axially retraced position in which the tissue removal assembly is disposed within the axial lumen of the hollow guidewire body to a second position in which the tissue removal assembly is positioned beyond the distal end of the guidewire body.
The tissue removal assembly typically comprises a rotatable drive shaft that has a shaped distal tip. In other embodiments, however, the tissue removal assembly may comprise a laser, an RF electrode, a heating element (e.g., resistive element), an ultrasound transducer, or the like. A lead of the tissue removal assembly may extend from proximally through an axial lumen of the hollow guidewire body.
In one preferred configuration, the hollow guidewire body is composed of a single hypotube. The hollow guidewire body optionally comprises a helical coil or solid wall tubular proximal portion integrally formed with the distal end portion. The distal end portion may comprise helical windings formed thereon. A pitch between adjacent helical windings on the distal portion decreases in the distal direction so as to increase a flexibility in the distal direction along the distal portion of the guidewire body. In other embodiments, the distal portion may have one or more sections that have a pitch that is constant throughout the distal portion, a pitch that increases in the distal direction, or the like.
A distal end portion of the hollow guidewire may comprise a plurality support ribs and openings or thinned portions that extend circumferentially about at least a portion of the distal end portion of the guidewire body. The plurality of openings or thinned portions may be used to increase the flexibility and/or bendability of the distal end portion, such that when the pull wires are actuated, the distal end portion is able to deflect without kinking of the distal end portion. The distal end portion may also include one or more radiopaque markers to assist in the fluoroscopic tracking of the hollow guidewire.
Similar to the other embodiments, the hollow guidewire may comprise one or more pull wires. The pull wires preferably comprise a curved surface that substantially corresponds to an inner surface of the axial lumen of the hollow guidewire, but other conventional shaped pull wires that don't substantially correspond to the inner surface of the axial lumen may also be used. The pull wire may be coupled to a removable proximal housing that is coupled to the proximal portion of the hollow guidewire body. The removable housing may comprise a connector assembly that allows for infusion or aspiration, one of more actuators (for controlling the rotation, axial movement of the drive shaft and/or steering of the distal end portion of the hollow guidewire body), a rotating member (e.g., drive motor), a control system, and/or a power supply.
In yet another aspect, the present invention provides a hollow guidewire that comprises a proximal portion and a distal portion. At least a part of the distal portion comprises helical windings that have a pitch between adjacent windings that decreases in the distal direction so that a distal end of the hollow guidewire is more flexible than the proximal portion of the hollow guidewire.
In yet another aspect, the present invention provides a method of crossing an occlusion or stenosis within a body lumen. The method comprises positioning an hollow guidewire having a drive shaft in the body lumen. The drive shaft is rotated. The drive shaft is moved from a retracted configuration to an expanded configuration. In the expanded configuration, the drive shaft may be used to create a path that is at least as large as a largest radial dimension (e.g., diameter) of the distal end of the hollow guidewire The hollow guidewire body and/or the drive shaft may then advanced into the occlusion or stenosis to create the path in the occlusion or stenosis.
In another aspect, the present invention provides a method of crossing an occlusion or stenosis within a body lumen. The method comprises advancing a guidewire through the body lumen. An access or support system is moved over the guidewire to the occlusion or stenosis. The guidewire is removed from the body lumen and exchanged with a steerable hollow guidewire having tissue removal assembly. The tissue removal assembly may then be used to remove at least a portion of the occlusion. For example, in one configuration the tissue removal assembly comprises a rotatable drive shaft. The drive shaft is rotated within a lumen of the hollow guidewire and is at least partially exposed through a distal opening in the hollow guidewire. The hollow guidewire and/or the drive shaft may be advanced to create a path through the occlusion or stenosis.
In another aspect, the present invention provides a kit. The kit has any of the hollow guidewire described herein and instructions for use that provide any of the methods described herein. In one configuration, the hollow guidewire comprises a tissue removal assembly, such as a rotatable drive shaft. The rotatable drive shaft has a shaped distal tip that is removably received within the axial lumen of the hollow guidewire. The instructions for use in passing occlusions or stenosis in a body lumen comprise rotating the inner wire within the steerable hollow guidewire and advancing the hollow guidewire and drive shaft or only advancing the rotating drive shaft into the occlusive or stenotic material to create a path through the occlusive or stenotic material. A package is adapted to contain the hollow guidewire, rotatable wire, and the instructions for use. In some embodiments, the instructions can be printed directly on the package, while in other embodiments the instructions can be separate from the package.
These and other aspects of the invention will be further evident from the attached drawings and description of the invention.
The systems, devices and methods according to the present invention will generally be adapted for the intraluminal treatment of a target site within a body lumen of a patient, usually in a coronary artery or peripheral blood vessel which is occluded or stenosed with atherosclerotic, stenotic, thrombotic, or other occlusive material. The systems, devices and methods, however, are also suitable for treating stenoses of the body lumens and other hyperplastic and neoplastic conditions in other body lumens, such as the ureter, the biliary duct, respiratory passages, the pancreatic duct, the lymphatic duct, and the like. Neoplastic cell growth will often occur as a result of a tumor surrounding and intruding into a body lumen. Removal of such material can thus be beneficial to maintain patency of the body lumen. While the remaining discussion is directed at passing through atheromatous or thrombotic occlusive material in a coronary artery, it will be appreciated that the systems and methods of the present invention can be used to remove and/or pass through a variety of occlusive, stenotic, or hyperplastic material in a variety of body lumens.
An apparatus 10 embodying features of the present invention is illustrated in
The drive motor 26 is attachable to a proximal end of the drive shaft 22 to move (i.e., rotate, translate, reciprocate, vibrate, or the like) the drive shaft 22 and shaped distal tip 24. An actuator or input device 82 is attached to the housing 12 to actuate the movement (e.g., control the rotation and/or axial movement) of the drive shaft 22. While not shown, an additional actuator or input device may be attached to housing 12 to control the deflection of a distal portion of the elongate member 14. The proximal end 16 of elongate member 14 is coupled to the housing 12 through a connector assembly 30. The connector assembly 30 limits the motion of the elongate member 14 while allowing the drive shaft 22 to rotate and translate within the elongate member 14. Optionally, some embodiments of the connector assembly 30 includes an aspiration or infusion port (not shown) for facilitating fluid exchange (e.g., delivery or removal) at the target site through the axial lumen 20.
As shown in
An exemplary embodiment of the elongate member 14 is best seen in FIGS. 3 to 9C. The elongate member 14 is preferably a flexible, hollow guidewire that has the flexibility, pushability, and torqueability to allow a user to advance the hollow guidewire directly through a tortuous blood vessel to the target site. Because of the high columnar strength of the hollow guidewire 14 there is typically no need for a separate guidewire to advance the hollow guidewire 14 to the lesion at the target site.
In the exemplary embodiment illustrated in
Hollow guidewire 14 is typically sized to be inserted through coronary, neuro, or peripheral arteries and can have a variety of diameters. The largest radial dimension (e.g., outer diameter) of the hollow guidewire is typically between approximately 0.009 inches and 0.040 inches, preferably between approximately 0.009 inches and 0.035 inches, and more preferably between approximately 0.009 inches and 0.024 inches, and most preferably between about 0.013 inches and approximately 0.014 inches so as to ensure compatibility with existing interventional cardiology catheters and stent systems. The length of the hollow guidewire 14 may be varied to correspond to the distance between the percutaneous access site and the target site, but is typically about five feet in length. For example, for a target site within the heart that is being accessed through the femoral artery, the hollow guidewire will typically have a length of approximately 175 cm. It should be noted however, that other embodiments of the hollow guidewire 14 may have dimensions that are larger or smaller than the above described embodiments and the present invention is not limited to the above recited dimensions.
Referring now to
In one configuration, the pitch between the helical windings 43 decreases in the distal direction so as to be increasingly flexible in the distal direction. Consequently, the distal portion 39 of the hypotube 37 will have an increasing flexibility in the distal direction. Advantageously, because the distal portion 39 is integrally formed with the proximal portion 45, there are no joints and there is an improved reliability and a reduced chance of disengagement between the distal portion 39 and the proximal portion 45. It may be desirable to have sections of the guidewire body to have no helical cuts, or to have laser cuts that have a pitch that increases in the distal direction so as to provide less flexibility over a portion of the hollow guidewire. The less flexible portion may be at the proximal portion, an intermediate portion, at or near the distal end of the hollow guidewire, or any combination thereof. For example, in one configuration, a proximal portion 45 of the hypotube may optionally have a solid wall with no laser cuts or helical spirals, and the remainder of the hypotube may have a helical laser edging (which may or may not have a decreasing pitch in the distal direction).
The laser cuts may extend all the way from the proximal end to the distal tip or the laser cuts may extend through less than all of the hypotube. The laser cuts used to create the helical windings may extend completely through the wall of the hypotube or it may extend only partially through the hypotube wall so as to create thinner wall portions (e.g., grooves).
Because the embodiment of
Similar to the embodiment of
Optionally, the pull wire may also be shaped so as to better conform with an inner surface 47 of the hollow guidewire 14. Substantially conforming a surface 49 of the pull wire 42 with the inner surface 47 of the hollow guidewire 14 increases the space between the rotating drive shaft 22 and the pull wire(s) 42 by allowing the pull wire 42 to be moved radially outward away from the drive shaft 22 and to contact the inner surface 47 at a tangential point. As shown in
The additional space between the drive shaft and the pull wire reduces the contact between the drive shaft 22 and the pull wire 42 and further reduces the possibility of breaking of the pull wire 42. For example, as shown in
Optionally, pull wire 42 may have a flattened surface 200 adjacent the drive shaft 22. Applicants have found that having a flat surface facing the rotating drive shaft further reduces the binding and friction between the pull wire 42 and the drive shaft 22 because the rotating drive shaft would only contact the pull wire at a tangential point, therefore minimizing friction and a possibility of twisting between the pull wire and drive shaft. In alternative embodiments, however, surface 200 may be curved, if desired, but as noted, such embodiments tend to have an increased chance of tangling.
The pull wire 42 will generally have a thickness T of between about 0.002 inches and about 0.040 inches and width W between about 0.002 inches and 0.080 inches. As can be appreciated, the dimensions of pull wire 42 will depend on the dimension of the inner lumen and the largest radial dimension of the hollow guidewire 14, and the only requirement is that the pull wire fit within the inner lumen of the hollow guidewire.
When the pull wire is moved proximally, the distal tip will deflect. To improve the deflection of the distal tip of the hollow guidewire, the hypotube may optionally comprise one or more set of circumferential openings or thinned portions 202 and support ribs 204 on the distal portion of the hypotube 37, distal of the helical windings 43. If the hollow guidewire only comprises ones pull wire 42, the hollow guidewire 14 will typically only comprise one set of support ribs 204 and circumferential openings or thinned portions 202 (
The radial slots, openings, and/or thinned portions 202 may be formed on the hypotube through laser edging that removes at least a portion of the material from the hypotube. The openings 202 will extend around less than the entire circumference of the hypotube, but if the laser merely creates thinner regions, it may be possible to have the thinner region extend completely around the hypotube. In preferred embodiments, however, the thinner portions and openings 202 typically extend between about 25% of the guidewire body (e.g., 90 degrees) and about 75% (e.g., 270 degrees) of the guidewire body.
The adjacent helical windings is separated by a kerf. As shown in
Optionally, as noted above, the hollow guidewire body 14 may also comprises a section third section 210 that is distal to sections 206, 208 that comprises a pitch that decreases in the distal direction (or increases in the distal direction). The taper may be liner or non-linear. In one configuration, the variable pitch section 210 spans 7.872 inches and has 598 variable pitches in which the proximal pitch of the section is 0.020328 inches and the distal most pitch is 0.006 inches. As can be appreciated, the hollow guidewire body 14 may comprise any number sections, and the sections may have any desired taper to the pitch.
The hollow guidewire body typically has one or more sections 212 that do not have any coils formed thereon (e.g., solid walled throughout). Typically, the sections that do not have any coils formed thereon 212 are transition areas between adjacent sections 206, 208, 210. Such transition areas 212 typically have a length between about 0.001 inches and 0.007 inches, but could be larger or smaller, if desired.
For any of the embodiments described herein, the helical coils of the hollow guidewire body 14 may be “left-handed” or “right-handed”. In some preferred embodiments, however, the different sections 206, 208, 210 of helical coils will have at least one left-handed coil section and at least one right-handed coil section. Typically, the left handed coil sections and the right handed coil sections are alternating along a length of the hollow guidewire body 141. As can be appreciated, when a right handed torque is applied to a coil that comprises all right-handed coils, the coils will torque without substantial “opening” of the coils. However, if a left-handed torque is applied to the same right-handed coils, the coils will tend to open and may affect the 1:1 torque transmission through the guidewire body 14. While the smaller kerf has been found to improve torque transmission, Applicants have found that having at least one left-handed section and at least one right-handed section further compensates for the opening of the coils when a torquing force is applied to the proximal end of the guidewire body. Consequently, similar amounts of torque may be transmitted to a distal tip of the hollow guidewire body when applying either a left-handed or right-handed torque.
Optionally, the hollow guidewire may comprise an integrally formed coil 214 at the distal tip. The distal coil 214 may be configured to threadedly receive a radiopaque coil (not shown), such as a platinum coil. The radiopaque coil may be soldered, glued, or otherwise attached to the distal coil 214 so as to provide a radiopaque marker for fluoroscopic tracking of the hollow guidewire body 14. The distal coil 214 may have any desired length and pitch, but in one exemplary configuration, the distal coil 214 is 0.027 inches long and has 5.75 helical windings that have a kerf of 0.0028 inches and a pitch of 0.005 inches.
Similar to the embodiments illustrated in
For the embodiments of
As shown in
Referring again to
Alternatively, as shown in
The drive shaft 22 can be composed of a shape retaining material, a rigid material, a flexible material, or can be composed of a plurality of materials. For example in some configurations, the drive shaft 22 can be comprised of nitinol, stainless steel, platinum-iridium, or the like. The distal tip 24 of the drive shaft 22 can have an enlarged tip, a preformed curve, or a preformed deflection (
Additionally, in some embodiments, the distal portion of the drive shaft 22 is radiopaque so that a physician can track the position of the drive shaft 22 using fluoroscopy. The drive shaft 24 typically has a diameter between approximately 0.010 inches and 0.005 inches. It should be appreciated that the dimension of the drive shaft will be slightly less than the inner diameter of the hollow guidewire so as to allow rotation without significant heat generation. Consequently, the dimensions of the drive shaft will vary depending on the relative inner diameter of the elongate member 14 and the present invention is not limited to the above described dimensions of the drive shaft.
In one embodiment, the distal tip 24 of the drive shaft is created using a shaped fixture 64. As shown in
As mentioned above, the distal tip 24 can take various shapes. One embodiment having a deflected distal tip 24 is shown in
The distal tip of the drive shaft can be configured optimally for the type of occlusion or stenosis to be penetrated. Some lesions are made up substantially of clot or thrombotic material that is soft and gelatinous.
In another exemplary embodiment shown in
In use, the distal tip 24 is rotated and advanced distally from a retracted position to an extended position into the soft material in the target lesion. If slow speed rotation is desired the user can rotate the drive shaft slowly by hand by grasping a knurled knob attached to the proximal end of the drive shaft (
As shown in
In use, drive shaft 24 is rotated and advanced to create a path distal of the elongate member 14 to create a path through the occlusion. The drive shaft 24 can be advanced and rotated simultaneously, rotated first and then advanced, or advanced first and then rotated. The drive shaft 22 is typically ramped up from a static position (i.e. 0 rpm) to about 5,000 rpm, 20,000 rpm with a motor. It should be noted, however, that the speed of rotation can be varied (higher or lower) depending on the capacity of the motor, the dimensions of the drive shaft and the elongate member, the type of occlusion to be bypassed, and the like. For example, if desired, the drive shaft can be manually rotated or reciprocated at a lower speed to macerate soft clots or to pass through lesions.
The distal tip of the drive shaft 22 can extend almost any length beyond the distal portion of the hollow guidewire. In most embodiments, however, the distal tip typically extends about 5 centimeters, more preferably from 0.05 centimeters to 5 centimeters, and most preferably between 0.05 centimeter and 2 centimeters beyond the distal portion of the hollow guidewire.
Referring now to
As shown generally in
In the embodiment shown in
As shown in
In most embodiments, actuation of the drive motor 26 and power supply 28 (e.g. rotation of the drive shaft) will be controlled independent from advancement of the drive shaft 22. However, while the actuator 82 is shown separate from the control system 27 and power supply 28 (
A connection assembly 30 is positioned on a proximal end of the housing to couple the elongate member 14 and the drive shaft 22 to the housing 12. In a preferred embodiment shown in
As shown in
The access or support system can be guided by the elongate member to the target site in a variety of ways. For example, as illustrated in
In another method of the present invention, the hollow guidewire 14 can be used to guide the support or access system to the target site without the use of a separate guide wire. The hollow guidewire 14 provides the flexibility, maneuverability, torqueability (usually 1:1), and columnar strength necessary for accurately advancing through the tortuous vasculature and positioning the distal end of the support or access system at the target site. The steerable distal portion can be deflected and steered through the tortuous regions of the vasculature to get to the target site. As shown in
Once the hollow guidewire reaches the target site within the blood vessel, the motor shaft 48, luer assembly 30, and housing 12 can be detached from the proximal end 46 of the drive shaft 22 so that the support or access system can be placed over the hollow guidewire. After the motor has been detached, the support or access system can be advanced over the guidewire and through the body lumen to the target site (
While the apparatus of the present invention is sufficient to create a path through the occlusion OM without the use of a support or access system, the apparatus 10 of the present invention can be used in conjunction with other atherectomy devices to facilitate improved removal or enlargement of the path through the occlusion. For example as shown in the above figures, the hollow guidewire 14 and the atherectomy device 108 can be advanced through the body lumen and positioned adjacent the occlusion OM. The drive shaft 22 is rotated and advanced to make an initial path through the occlusion (
In another aspect, the invention provides medical kits. As shown in
While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. For example, while the above description focuses on a rotatable drive shaft to remove material from the body lumen, the hollow guidewires of the present invention may incorporate other tissue removal assemblies. The tissue removal assembles may be fixedly positioned at the distal tip of the hollow guidewire or movable between a first position (e.g., retracted position) and a second position (e.g., deployed position). The tissue removal assembly may take on the form of a laser, LED, RF electrode or other heating element, an ultrasound transducer or the like. Thus, instead of a drive shaft, the above tissue removal assemblies may have a lead extend through the axial lumen to the tissue removal assembly that is fixedly or movably positioned at or near the distal end of the hollow guidewire. Moreover, while not explicitly illustrated, a person of ordinary skill in the art will recognize that aspects of one configuration of the hollow guidewire body may be used with other configurations of the hollow guidewire body. For example, while the guidewire body of
The present application is a continuation-in-part of U.S. patent application Ser. No. 09/644,201, entitled “Guidewire for Crossing Occlusions or Stenoses,” (allowed), which claimed benefit under 37 C.F.R. § 1.78 to U.S. Provisional Patent Application No. 60/195,154, filed Apr. 6, 2000, entitled “Guidewire for Crossing Occlusions or Stenosis,” the complete disclosures of which are incorporated herein by reference. The present application is also related to U.S. patent application Ser. No. 09/030,657, filed Feb. 25, 1998, and U.S. patent application Ser. No. 09/935,534, filed Aug. 22, 2001, now U.S. Pat. No. 6,746,422, entitled “Steerable Support System with External Ribs/Slots that Taper,” the complete disclosure of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60195154 | Apr 2000 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09644201 | Aug 2000 | US |
| Child | 10999457 | Nov 2004 | US |
