Medical Device Having a Deflectable Distal End

Abstract

The medical device includes an elongate member having a proximal end, a distal end, and a body extending between the proximal and distal ends, wherein at least a first portion of the elongate member includes a first segment made from a shape memory material and a second segment made from a non-shape memory material, the first portion being a distal portion of the elongate member, the first and second segments of the distal portion of the elongate member being secured to one another along respective longitudinal sides, and the first segment being configured to undergo a change in length to bend the distal portion of the elongate member.

Description

[Technical field]

[0001] The field of this application relates to medical devices, and more particularly to deflectable guidewires, pushwires, and delivery wires for medical devices, and medical devices having such guidewires, pushwires, and delivery wires. [Background technology]

[0002] The use of endovascular implants, such as stents, stent grafts, flow diverters, aneurysm occlusion devices, vena cava filters, etc., has become an effective method for treating many types of vascular diseases. Generally, a suitable endovascular implantable device is inserted into a patient's vasculature and navigated through the vasculature to the target implantation site using a delivery system.

[0003] A minimally invasive delivery system includes a catheter, a push wire or delivery wire, or the like, which is percutaneously introduced into the patient's vascular system via a guide wire. In a vascular application commonly used to access a target site in a patient, a guide wire is inserted through an incision in the femoral artery near the groin and advanced until the target site is reached. A catheter is then advanced over the guide wire until the open distal end of the catheter is positioned at the target site. Concurrently with or after positioning the distal end of the catheter at the target site, an intravascular implant is advanced through the catheter via the push wire or delivery wire.

[0004] In certain applications, such as neurovascular, guidewires, pushwires, and delivery wires must navigate tortuous and complex vasculature, including navigation through relatively fragile vessels in the brain, and often must change direction or even turn around. Thus, these wires (i.e., guidewires, pushwires, and delivery wires) should have adequate flexibility, kink resistance, pushability, and torqueability to successfully navigate vasculature, such as the cerebral and peripheral vasculature. Adequate flexibility and kink resistance of these wires allow them to pass through relatively tight bends without breaking or permanently deforming. Additionally, forces applied to the proximal end of these wires must be transferred to the distal end to provide adequate pushability (axial stiffness) and torqueability (rotation). Achieving a balance of these functions is highly desirable. For example, guidewires, pushwires, and / or delivery wires may include variable stiffness sections (e.g., variable ratios of materials with selective reinforcements, such as braids, coils, etc.) suitable to provide sufficient flexibility, kink resistance, pushability, and torqueability to achieve navigation through the vasculature.

[0005] Additionally, in certain applications, it may be desirable for the distal end of the guidewire, pushwire, and / or delivery wire to be configured to deflect or bend during navigation through a vessel and / or when approaching a target site within the vessel, thereby enabling access to the target site. Some guidewires, pushwires, and / or delivery wires have pre-bent distal ends to reach certain tight bends in the vasculature. However, these pre-bent wires may inadvertently bump, snag, and / or scrape against the inner walls of the vessel during navigation and advancement of the wire, especially in tortuous and complex vasculature, and in branched vessel walls, aneurysms, and other anatomical features. Such navigational difficulties may undesirably increase the time required to perform a medical procedure and further increase the risk of vascular trauma or damage. Summary of the Invention

[0006] A medical device includes an elongate member having a proximal end, a distal end, and a body extending between the proximal and distal ends, at least a first portion of the elongate member including a first segment made of a shape memory material and a second segment made of a non-shape memory material, the first portion being a distal portion of the elongate member, the first and second segments of the distal portion of the elongate member being fixed to one another along respective longitudinal sides, and the first segment being configured to undergo a change in length to bend the distal portion of the elongate member.

[0007] Optionally, the first segment is configured to change length in response to a temperature above body temperature.

[0008] Optionally, the temperature is at least 10 degrees Fahrenheit above body temperature.

[0009] Optionally, the medical device further includes an energy source coupled to the elongate member, the energy source configured to supply an electrical current to the elongate member to increase a temperature of a distal portion of the elongate member.

[0010] Optionally, the medical device further includes a user interface configured to allow a user to adjust the current from the energy source to effect a corresponding change in the curvature of the bend of the distal portion of the elongate member.

[0011] Optionally, the shape memory material of the first segment comprises shape memory Nitinol.

[0012] Optionally, the non-shape memory material of the second segment comprises non-shape memory Nitinol.

[0013] Optionally, the elongate member includes a second portion proximal to the distal portion.

[0014] Optionally, the second portion and the distal portion of the elongate member are made from different materials.

[0015] Optionally, the second portion comprises stainless steel and the distal portion comprises nitinol.

[0016] Optionally, the second portion of the elongate member comprises non-shape memory nitinol and the first segment of the distal portion of the elongate member comprises shape memory nitinol.

[0017] Optionally, the medical device further comprises a coil coupled to the elongate member.

[0018] Optionally, the medical device further includes a jacket or slotted tube disposed around at least a distal portion of the elongate member.

[0019] Optionally, the medical device further includes a marker coupled to a distal portion of the elongate member.

[0020] A medical device includes an elongate member having a proximal end, a distal end, and a body extending between the proximal and distal ends, at least a first portion of the elongate member including a first segment and a second segment, the first portion being a distal portion of the elongate member, the first segment and the second segment of the distal portion of the elongate member being fixed to one another along respective longitudinal sides, the first segment configured to undergo a change in length in response to a temperature greater than body temperature, and the second segment configured to undergo zero change in length or a reduced change in length in response to temperature compared to the first segment.

[0021] Optionally, the temperature is at least 10 degrees Fahrenheit above body temperature.

[0022] Optionally, the first segment is configured to undergo a change in length to bend a distal portion of the elongate member.

[0023] Optionally, the medical device further includes an energy source coupled to the elongate member, the energy source configured to deliver an electrical current to the elongate member to increase a temperature of a distal portion of the elongate member.

[0024] Optionally, the medical device further includes a user interface configured to allow a user to adjust the current from the energy source to effect a corresponding change in the curvature of the bend of the distal portion of the elongate member.

[0025] Optionally, the first segment comprises a shape memory material and the second segment comprises a non-shape memory material.

[0026] Optionally, the shape memory material of the first segment comprises shape memory Nitinol and the non-shape memory material of the second segment comprises non-shape memory Nitinol.

[0027] Optionally, the elongate member includes a second portion proximal to the distal portion.

[0028] Optionally, the second portion and the distal portion of the elongate member are made from different materials.

[0029] Optionally, the second portion comprises stainless steel and the distal portion comprises nitinol.

[0030] Optionally, the second portion of the elongate member comprises non-shape memory nitinol and the first segment of the distal portion of the elongate member comprises shape memory nitinol.

[0031] Optionally, the medical device further comprises a coil coupled to the elongate member.

[0032] Optionally, the medical device further includes a jacket or slotted tube disposed around at least a distal portion of the elongate member.

[0033] Optionally, the medical device further includes a marker coupled to a distal portion of the elongate member.

[0034] Other and further aspects and features will become apparent from a reading of the following detailed description. [Brief description of the drawings]

[0035] The drawings illustrate the design and utility of the embodiments, with similar elements being referred to by common reference numerals. The drawings are not necessarily drawn to scale. To better understand how the above and other advantages and objects are obtained, a more particular description of the embodiments illustrated in the accompanying drawings is provided. These drawings illustrate only exemplary embodiments, and therefore should not be considered as limiting the scope of the claims. [Figure 1] 1A-1B are cross-sectional views of a guidewire being introduced into a branched vasculature. [Diagram 2] 2A-2B are cross-sectional views of another guidewire being introduced into a branched vasculature. [Diagram 3] FIG. 3 shows a medical device having a catheter for delivering an implant. [Figure 4] 4A-4B show one embodiment of a guidewire, particularly showing the distal segment of the guidewire. [Diagram 5] FIG. 5 is a cross-sectional view of the guidewire of FIGS. 4A-4B, particularly showing the distal end portion of the guidewire being introduced into a branched vasculature. [Figure 6] FIG. 6 is a cross-sectional view of the guidewire of FIGS. 4A-4B, particularly showing the distal end portion of the guidewire being introduced into a branched vasculature. [Figure 7] FIG. 7 is a cross-sectional view of a different embodiment of a medical device. [Figure 8] FIG. 8 is a cross-sectional view of a different embodiment of a medical device. [Figure 9] FIG. 9 is a cross-sectional view of a different embodiment of a medical device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Various embodiments are described below with reference to the drawings, which are not necessarily to scale, and in which elements of similar structure or function are represented by like reference numerals throughout the drawings, and it should be understood that the drawings are intended only to facilitate the description of the embodiments, and are not intended as an exhaustive description of the claimed invention, or as limiting its scope, which is defined only by the appended claims and equivalents thereof.

[0037] Moreover, each illustrated embodiment need not have all of the illustrated features, and aspects or advantages discussed in connection with a particular embodiment are not necessarily limited to that embodiment and may be implemented in any other embodiment even if not shown or explicitly described.

[0038] For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.

[0039] All numerical values ​​herein are intended to be modified by the term "about," whether or not expressly stated. The term "about" generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term "about" may include numerical values ​​that are rounded to the nearest significant figure.

[0040] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0041] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0042] 1A-1B show a method of accessing a branch vasculature 10 using a guidewire 30 having a distal end 34. The distal segment of the guidewire 30 (including the distal end 34) is composed of a single material (e.g., Nitinol) with shape memory properties and can be thermally or electrically activated. The branch vasculature 10 includes a main vessel 20, a first vessel branch 22, a second vessel branch 26, and a bifurcation angle 24 between the first branch 22 and the second branch 26. The guidewire 30 is advanced through the main vessel 20 and manipulated to access a target site within the first vessel branch 22. The guidewire 30 advances along the path of least resistance by sliding within the main vessel 20, which favors access to the second vessel branch 26 (FIG. 1A). Although the attending physician can take corrective measures to steer the guidewire 30 into the desired first branch vessel 22, in some cases, the distal end 34 of the guidewire 30 may still get caught and hit the bifurcation angle 24 (FIG. 1B). This is because the extreme ductility of Nitinol may result in poor shape retention when the distal segment is deflected when a single-material guidewire is operated below its activation temperature (such as its austenitic finish temperature). When the distal end 34 of the guidewire 30 hits the bifurcation angle 24, it may damage the vessels, especially the relatively fragile neurovasculature. This may also increase the duration of the medical procedure if multiple attempts to steer the guidewire 30 towards the desired first branch vessel 22 are unsuccessful.

[0043] In some cases, a guidewire may have a pre-bent distal segment to aid in navigation through a particular vessel. However, such a guidewire may unintentionally cause trauma to the vessel. As a further example, FIGS. 2A-2B show a method of accessing a branched vasculature 10, which includes the use of a guidewire 40 having a pre-bent distal segment 44. Due to the geometry of the branched vasculature 10, as the guidewire 40 attempts to steer toward a desired first vessel branch 22, the guidewire 40 may attempt to access an unintended second vessel branch 26. As a result, the pre-bent distal segment 44 of the guidewire 40 may catch on the inner wall 21 of the vessel 20, causing trauma (FIG. 2A), and / or catch on the bifurcation angle 24, causing trauma (FIG. 2B). As shown in FIG. 2B, after the pre-bent distal segment 44 impinges on the bifurcation angle 24, any attempt to advance the distal segment 44 further distally may deflect the distal segment 44 toward the proximal end, further increasing the risk of trauma to the vessel.

[0044] 3 illustrates an implant delivery system 100 according to some embodiments. The implant delivery system 100 includes an elongate sheath 110, an elongate tubular member 120 slidably disposed within the elongate sheath 110, and a guidewire (or wire) 500 slidably disposed within the elongate sheath 110. In some embodiments, the guidewire 500 is configured to access a patient's blood vessel. In other embodiments, the guidewire 500 may be configured to deliver an implant (not shown). In such cases, the guidewire 500 may function as a delivery wire or a push wire.

[0045] The elongated member 120 has a tubular configuration and may take the form of, for example, a sheath, a catheter, a microcatheter, etc. The elongated member 120 has a proximal end 130, a distal end 160, and a lumen 170 extending through the elongated member 120 between the proximal end 130 and the distal end 160. The proximal end 130 of the elongated member 120 remains outside the patient's body and is accessible to an operator during use of the implant delivery system 100, while the distal end 160 of the elongated member 120 has a size and dimensions to reach remote locations in the vasculature. The elongated member 120 is advanced over a guidewire 500 (examples of which are described with reference to FIGS. 4A-4B ) until the distal end 160 of the elongated member 120 is positioned at the target site. Simultaneously with or after the distal end 160 of the elongated member 120 is positioned at the target site, an intravascular implant may be advanced through the elongated member 120 via the guidewire 500.

[0046] As shown in FIG. 3, the implant delivery system 100 also includes a handle 400 coupled to a proximal end of the guidewire 500 (FIG. 4A). The handle 400 of the implant delivery system 100 includes a user interface 420 configured to allow a user (e.g., a physician, a technician, etc.) to control bending of the guidewire 500. Although the user interface 420 is shown as being implemented on the handle 400, in other embodiments, the user interface 420 may be implemented as a device separate from the handle 400. For example, in other embodiments, the user interface 420 may be a computer or any electronic device (e.g., a cell phone, a tablet, etc.) capable of generating electrical and / or radio frequency signals. The user interface 420 may include an electrical controller, a power source, etc., configured to deliver electrical current to the components of the implant delivery system 100 (e.g., the guidewire 500). In some embodiments, the user interface 420 may include one or more controls, which may be one or more physical buttons, knobs, switches, etc. In other embodiments, the one or more controls may be a touch screen having graphic elements configured to allow a user to selectively actuate the guidewire 500 to bend the guidewire 500.

[0047] In some embodiments, the handle 400 may also be optionally coupled to the proximal end 130 of the elongate member 120 and / or the proximal end 113 of the elongate sheath 110. In such cases, the user interface 420 may allow a user to control the bending of the elongate member 120 and / or the elongate sheath 110. The elongate member 120 and / or the elongate sheath 110 may include actuation elements (e.g., steering wires) actuable in response to tension provided by the user interface 420, thereby bending the elongate member 120 and / or the elongate sheath 110. The user interface 420 may include one or more controls to allow a user to apply tension to the steering wires. In some embodiments, the one or more controls may be one or more physical buttons, knobs, switches, etc. In other embodiments, the one or more controls may be a touch screen having graphic elements configured to allow a user to actuate the actuation elements of the elongate member 120 and / or the elongate sheath 110.

[0048] In other embodiments, the elongate member 120 and / or the elongate sheath 110 may not include a steering wire. In such cases, the bending of the elongate member 120 and / or the elongate sheath 110 may be controlled by the guidewire 500.

[0049] In further embodiments, the delivery system 100 may not include the sheath 110 and / or the elongate member 120.

[0050] Additionally, in other embodiments, system 100 need not be an implant delivery system. Instead, system 100 may be another type of medical device or a component of another type of medical device. For example, system 100 with guidewire 500 may be part of a drug delivery system, a biopsy system, a therapeutic system that includes an energy source, and the like.

[0051] 4A-4B show a guidewire 500 according to some embodiments. As shown, the guidewire 500 includes a proximal end 510, a distal end 512, and a body 515 extending between the proximal end 510 and the distal end 512. The guidewire 500 also includes a distal portion 520 having the distal end 512. The guidewire 500 also has a linear configuration that is relatively straight (compared to a curved configuration) at room temperature and / or body temperature, but flexibly curves when subjected to an external force. The guidewire 500 further includes a variable stiffness portion that goes from a high stiffness at the proximal portion to a low stiffness along the distal portion 520 with a gradually decreasing stiffness along the body 515. Such a configuration can provide the guidewire 500 with sufficient flexibility, buckling resistance, pushability, and torqueability for navigation through the vasculature. Alternatively, the variable stiffness portion of the guidewire 500 can be discrete rather than graduated. For example, a first portion of guidewire 500 closer to proximal end 510 than distal end 512 may have a first stiffness, a second portion of guidewire 500 distal to the first portion may have a second stiffness, and a third portion of guidewire 500 distal to the second portion may have a third stiffness. The third portion may be distal portion 520. The first stiffness may be greater than the second stiffness, and the second stiffness may be greater than the first stiffness.

[0052] It should be noted that the term "body temperature" as used herein may refer to a range of temperatures, such as a temperature range of 95-107 degrees Fahrenheit, more preferably a temperature range of 96-100 degrees Fahrenheit, and more preferably a temperature range of 97-99 degrees Fahrenheit. Also, the term "room temperature" as used herein may refer to any temperature different from body temperature. For example, room temperature may be any temperature lower than body temperature. In some embodiments, room temperature may be any temperature at least 10 degrees Fahrenheit lower than body temperature, or at least 20 degrees Fahrenheit lower than body temperature.

[0053] As shown in FIGS. 4A-4B, the distal portion 520 of the guidewire 500 includes a first segment 522 and a second segment 524, with the first segment 522 coupled to the second segment 524. The distal portion 520 of the guidewire 500 may optionally include a radiopaque marker 525. The first segment 522 of the distal portion 520 of the guidewire 500 is configured to change from a relatively straight configuration to a more curved configuration in response to a temperature change, while the second segment 524 is independent of the temperature change. As the first segment 522 changes its shape from its relatively straight configuration in response to a temperature change, the first segment 522 displaces or moves the second segment 524 along therewith, thereby causing the distal end 512 of the distal portion 520 of the guidewire 500 to deflect as represented by the dashed lines in FIG. 4B (as will be described in more detail below). In the illustrated embodiment, the first segment 522 is configured to contract in response to a change in temperature. In such a case, contraction of the first segment 522 causes the distal portion 520 of the guidewire 500 to bend in a direction toward the first segment 522. In other embodiments, the first segment 522 is configured to expand in response to a change in temperature. In such a case, expansion of the first segment 522 causes the distal portion 520 of the guidewire 500 to bend in a direction toward the second segment 524.

[0054] In some embodiments, the first segment 522 of the distal portion 520 of the guidewire 500 is constructed of shape memory nitinol and the second segment 524 of the distal portion 520 of the guidewire 500 is constructed of non-shape memory nitinol. In other embodiments, the first segment 522 may be made of other shape memory materials, such as shape memory metals, shape memory alloys, etc. Also, in other embodiments, the second segment 524 may be made of other non-shape memory materials, such as non-shape memory metals, non-shape memory alloys, etc. The first segment 522 and the second segment 524 of the distal portion 520 are fixedly attached (e.g., laminated) at one or more points along the longitudinal axis of the guidewire 500 by a suitable technique, such as solder, adhesive, laser spot welding, etc.

[0055] In some embodiments, the first segment 522 of the distal portion 520 is configured to be thermoelectrically actuated to deflect the distal portion 520 of the guidewire 500. In the illustrated embodiment, the first segment 522 is thermomechanically treated to shorten (e.g., shorten) when heated above an activation temperature. The second segment 524 does not have shape memory behavior, and thus when the distal portion 520 of the guidewire 500 is heated above an activation temperature, the first segment 522 shortens while the second segment 524 retains its length. The shortening of the first segment 522 relative to the second segment 524 causes the distal portion 520 of the guidewire 500 to bend. The shortening / contraction of the first segment 522 causes a deflection of the distal portion 520 of the guidewire 500, as represented by the dashed lines in FIG. 4B.

[0056] In some embodiments, the activation temperature can be the austenite finish temperature (AF). As used herein, the term austenite finish temperature ("Af") is the temperature at which the transformation from martensite to austenite is completed upon heating of a material, such as a metal alloy (e.g., Nitinol). When the material is fully martensite and is heated, austenite begins to form at the austenite start temperature (As) and is finished at the austenite finish temperature (Af).

[0057] In some embodiments, heating of the distal portion 520 of the guidewire 500 can be accomplished by passing an electric current through the guidewire 500 via the user interface 420 (FIG. 4A) at the handle 400. The resistivity of the material forming the distal portion 520 results in controllable heating with power modulation at the user interface 420. In some embodiments, the Af temperature of the first segment 522 can be selected to be slightly above body temperature so that actuation of the distal portion 520 of the guidewire 500 does not require heating beyond safe limits for blood contact. In that way, the distal portion 520 of the guidewire 500 will not deflect during storage or advancement of the guidewire until an electric current is applied to the guidewire 500 causing the Af temperature of the first segment 522 to rise slightly above body temperature.

[0058] It should be noted that by combining the first segment 522 and the second segment 524 of the distal portion 520 in a stacked configuration, the distal portion 520 of the guidewire 500 can achieve a large deflection with a substantially shorter first segment 522. The amount of deflection of the distal portion 520 of the guidewire 500 is governed by the difference in properties of the first segment 522 and the second segment 524 and / or the amount of current provided to the distal portion 520 of the guidewire 500. In some embodiments, the non-shape memory second segment 524 may have independently tuned and / or selected mechanical properties to also provide shapeability and functionality for the distal portion 520 of the guidewire 500.

[0059] In some embodiments, the length of the first segment 522 of the distal portion 520 of the guidewire 500 can be between 5 mm and 15 mm, or between 5 mm and 20 mm, or between 5 mm and 3,400 mm (e.g., approximately the entire length of the guidewire). The second segment 524 can be shorter than the first segment 522, can be the same length as the first segment 522, or can be longer than the first segment 522.

[0060] The deflection of the distal portion 520 of the guidewire 500 is caused by the magnitude of the difference between the thermal actuation coefficient of the first segment 522 and the non-thermal actuation coefficient of the second segment 524. In some embodiments, the thermal / electrical actuation of the distal portion 520 of the guidewire 500 can cause a difference in shortening / contraction or length change of four percent or more (>4%) with a relatively small change in temperature range (e.g., 5 degrees Fahrenheit or more, 10 degrees Fahrenheit or more, 15 degrees Fahrenheit or more, etc.), achieving a large deflection of the distal portion 520 with a small change in temperature. In some cases, the narrowest achievable radius of curvature of the distal portion 520 of the guidewire 500 is in the range of 0.05 inches (e.g., 0.05 inches + / - 0.02 inches). In other cases, the radius of curvature of the distal portion 520 of the guidewire 500 may be higher, such as 0.1 inches, 0.2 inches, 0.4 inches, 0.6 inches, etc. (± 0.05 inches).

[0061] In some embodiments, the deflection angle of the distal portion 520 of the guidewire 500 may be controlled by heat / current modulation applied to the guidewire 500. The current may be applied using a monopolar technique, where the current completes a current circuit from the guidewire 500 through the patient's tissue to a return pad, or a bipolar technique, where the current return path is along the guidewire 500 back to the electrical controller of the user interface 420. Also, in some embodiments, the curve curvature of the distal portion 520 may be selectively adjusted using controls on the handle 400. The controls may be manipulated to change the amount of current applied to the distal portion 520 of the guidewire 500. In one mode of operation, increasing the amount of current may increase the curve curvature at the distal portion 520 of the guidewire 500. In another mode of operation, decreasing the amount of current may decrease the curve curvature at the distal portion 520 of the guidewire 500.

[0062] Additionally, in some embodiments, annealing parameters can be adjusted to achieve a desired level of elasticity and formability in the material (e.g., Nitinol) forming the distal portion 520 of the guidewire 500. In some embodiments, the distal portion 520 of the guidewire 500 can be heat treated to a semi-annealed or partially annealed state such that the second segment 524 is shapeable and can retain a standard shapeable guidewire tip, but the distal portion 520 of the guidewire 500 still has a thermoelectrically actuated first segment 522 such that the distal portion 520 can be actively deflected as needed. In such cases, active deflection (e.g., application of electrical current or heat to the guidewire 500) may not be required during some uses of the guidewire 500, but active deflection can be used to navigate the guidewire 500 through more difficult and tortuous vasculature during other uses.

[0063] 5-6 illustrate a method of accessing a branch vasculature 10 using a guidewire 500. The branch vasculature 10 includes a main vessel 20, a first branch vessel 22, a second branch vessel 26, and a bifurcation angle 24 between the first branch vessel 22 and the second branch vessel 26. A guidewire 500 having a distal portion 520 is advanced through the main vessel 20 and manipulated to access a target site within the first branch vessel 22.

[0064] As the guidewire 500 is advanced through the patient's body, the user can manipulate the user interface 420 to actuate the guidewire 500 to bend in a desired manner. With the aid of known imaging techniques and a marker 525 disposed at the distal end 512 of the guidewire 500, the user can identify the location of the distal portion 520 of the guidewire 500 within the main blood vessel 20 (FIG. 5). If the user determines that bending of the distal portion 520 is necessary, the user can manipulate the user interface 420 to apply heat or electrical current to the distal portion 520 of the guidewire 500 to thermally or electrically actuate the first segment 522 comprised of a shape memory material, causing the distal portion 520 of the guidewire 500 to deflect toward the desired first branch vessel 22 (FIG. 6). To achieve this deflection of distal portion 520 of guidewire 500, the angle of distal portion 520 relative to the longitudinal axis of the elongate body of guidewire 500, as illustrated by angle "Φ", can range from about 5 to about 60 degrees or more.

[0065] As illustrated above, the bending of distal portion 520 allows distal end 512 of guidewire 500 to be steered at different curvatures along a passageway (e.g., a blood vessel) within a patient. In some embodiments, guidewire body 515 may be rotated about its longitudinal axis such that bending occurs in different bending planes. Also, in some embodiments, the degree of bending (e.g., curvature, angle, etc.) of guidewire 500 may be adjusted by varying the amount of heat or electrical current provided by user interface 420.

[0066] After the distal end 512 of guidewire 500 is desirably positioned within the patient, elongate member 120 and / or sheath 110 of Figure 3 may then be advanced over guidewire 500 and utilized in a medical procedure to diagnose and / or treat the patient. For example, elongate member 120 and / or sheath 110 may be used to deliver a substance (e.g., a drug, a medicine, a contrast agent, saline, etc.), deploy a device (e.g., an implant, a tissue dissector, an imaging scope, a therapeutic energy source, etc.), or perform other functions in different embodiments.

[0067] It should be noted that guidewire 500 is not limited to the example of Figures 4A-4B, and guidewire 500 may have other configurations in other embodiments. In other embodiments, guidewire 500 may include more than two distal segments that are joined together to form distal portion 520 of guidewire 500. For example, in other embodiments, distal portion 520 may have three distal segments that are stacked and joined together to form distal portion 520 of guidewire 500. In other embodiments, guidewire 500 may include other components along the longitudinal axis of guidewire 500, such as an outer jacket, sleeves, reinforcing segments, coils, radiopaque coatings, markers, etc.

[0068] In other embodiments, wire 500 may be a push wire or a delivery wire rather than a guide wire.

[0069] In some embodiments, wire 500 can have a stiffer proximal portion compared to distal portion 520. The stiffer proximal portion can be at least 30%, at least 50%, at least 70%, or at least 80% of the overall length of wire 500. Also, in some embodiments, wire 500 can have a proximal portion proximal to distal portion 520, which can be made from stainless steel, nitinol, cobalt chromium alloy (e.g., MP35N alloy), other alloys, or combinations thereof.

[0070] In other embodiments, the wire 500 can be formed of stainless steel (or other rigid alloy) along the proximal portion and have Nitinol at the distal portion 520 .

[0071] In other embodiments, wire 500 can include a hybrid core. For example, the portion of body 515 proximal to distal portion 520 can be made from Nitinol and another material (e.g., stainless steel) to provide a stiffer proximal portion of wire 500.

[0072] In further embodiments, the wire 500 can have a Nitinol segment extending the entire length of the wire 500. In such cases, one or more portions of the Nitinol core can be heat treated to provide shape memory properties, similar to those described herein.

[0073] In further embodiments, wire 500 can function as the corewire or backbone of various elongated medical devices, such as complex guidewires, sheaths, catheters, etc. The compact size of wire 500 allows it to be incorporated into sheaths, catheters, etc. as a corewire without affecting other performance characteristics (torque transmission, stiffness, tip formability, etc.).

[0074] 7A-9 show different examples of medical devices incorporating wires 500 as described herein. The wires 500 in FIGS. 7A-9 decrease in diameter (i.e., taper) from the proximal end (not shown) and / or body 515 of the wire 500 toward the distal end 512. The tapering of the wire 500 may be constant in the decrease in diameter of the wire 500 along the longitudinal axis 550 (as shown in FIG. 7A), or may have distinct transitions between tapering sections (as shown in FIGS. 8-9), or may be a combination thereof.

[0075] With reference to FIG. 7A, the medical device 580 includes the wire 500 and an outer jacket 700 disposed around at least a portion of the distal portion 520 of the wire 500. The outer jacket 700 may be any tubular member and may be made of any suitable material, such as a metal or polymer. In some embodiments, the outer jacket 700 may be made of Nitinol. As can be seen from detailed FIG. 7B, the outer jacket 700 has multiple slots and / or openings to enhance flexibility. As non-limiting examples, the outer jacket 700 may be implemented using a slotted hypotube, a coiled sleeve, a tungsten-filled polymer sleeve, or combinations thereof. The medical device 580 may further include a coil 720 disposed around the distal portion 520 of the wire 500 and concentrically disposed between the distal portion 520 of the wire 500 and the outer jacket 700. The coil 720 may be made of a radiopaque material and / or platinum tungsten. The medical device 580 further includes a blunt atraumatic tip 600 coupled to the distal portion 520 of the wire 500 .

[0076] 8 illustrates another medical device 580 having a wire 500 and an outer jacket 800 concentrically disposed around at least a distal portion 520 of the wire 500. The outer jacket 800 is constructed from a suitable polymeric material. In other embodiments, the outer jacket 800 may be made from other materials. The medical device 580 further includes a blunt atraumatic tip 600 coupled to the distal portion 520 of the wire 500.

[0077] 9 illustrates another medical device 580 having a wire 500 and a coil 900 concentrically disposed about at least a distal portion 520 of the wire 500. As shown, a proximal end 920 of the coil 900 is secured to the body 515 of the wire 500 and a distal end 940 of the coil 900 is secured to the distal portion 520 of the wire 500. This securing may be accomplished using adhesives, welding, mechanical connectors, fusion, or the like. The medical device 580 further includes a blunt atraumatic tip 600 coupled to the distal portion 520 of the wire 500.

Claims

1. A medical device, an elongate member having a proximal end, a distal end, and a body extending between the proximal and distal ends; at least a first portion of the elongate member includes a first segment made from a shape memory material and a second segment made from a non-shape memory material, the first portion being a distal portion of the elongate member; the first and second segments of the distal portion of the elongate member are secured to one another along respective longitudinal sides to form a stacked configuration; the first segment is configured to undergo a change in length to bend a distal portion of the elongate member; The medical device further comprises a tubular member disposed about the first segment and the second segment of the first portion of the elongate member.

2. The medical device of claim 1 , wherein the first segment is configured to change length in response to an increase in temperature of the first segment above body temperature.

3. The medical device of claim 2 , wherein the temperature is at least 10 degrees Fahrenheit above body temperature.

4. The medical device of any of claims 1 to 3, wherein the shape memory material of the first segment comprises shape memory nitinol and the non-shape memory material of the second segment comprises non-shape memory nitinol.

5. The medical device of any one of claims 1 to 3, wherein the elongate member includes a second portion proximal to the distal portion, the second portion being made from a different material than the distal portion.

6. 6. The medical device of claim 5, wherein the second portion is made from stainless steel or non-shape memory nitinol and the distal portion is made from shape memory nitinol.

7. The medical device of any of claims 1 to 6, wherein the tubular member comprises a jacket or a slotted tube disposed around at least a distal portion of the elongate member.

8. The medical device of any of claims 1 to 7, further comprising a marker coupled to a distal portion of the elongate member.

9. 2. The medical device of claim 1, wherein the first segment is configured to undergo the change in length in response to a temperature greater than body temperature, and the second segment is configured to have zero or a reduced change in length in response to temperature compared to the first segment.

10. The medical device of claim 5 , wherein the second portion comprises stainless steel and the distal portion comprises Nitinol.

11. The medical device of claim 5 , wherein the second portion of the elongate member comprises non-shape memory nitinol and the first segment of the distal portion of the elongate member comprises shape memory nitinol.

12. 13. A medical treatment system including the medical device of claim 1, further comprising an energy source coupled to the elongate member, the energy source configured to supply an electrical current to the elongate member to increase a temperature of a distal portion of the elongate member.

13. The medical procedure system of claim 12 , further comprising a user interface configured to allow a user to adjust an electrical current from the energy source to effect a corresponding change in curvature of a bend in a distal portion of the elongate member.

14. The medical device of claim 1 , wherein the medical device is a guidewire or a catheter.

15. The medical device of claim 1 , wherein the elongate member includes a second portion proximal to the distal portion, the second portion being stiffer than the distal portion.

16. The medical device of claim 15, wherein the second portion is tapered, and the elongated member further comprises a third portion proximate the second portion and a fourth portion proximate the third portion, wherein the third portion is not tapered, and the fourth portion is tapered.

17. The medical device of claim 1, wherein the first and second segments of the distal portion of the elongated member are fixed to each other by soldering or welding along their respective longitudinal sides to form a laminated configuration.

18. The medical device of claim 1, wherein at least a portion of the tubular member is separated from the laminate structure, defining a space between at least a portion of the tubular member and the laminate structure.

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