Medical device with radiopaque coil

Abstract

A medical device (100) includes an elongate member having a proximal end (112), a distal end (114), and a body (116) extending from the proximal end to the distal end; a blunt tip (182) at or coupled to the distal end of the elongate member; and a radiopaque coil (190) coupled to the elongate member; wherein the radiopaque coil is formable and has a shape retention characteristic, and wherein a flexural stiffness of the formable radiopaque coil having the shape retention characteristic is at least 10% of a flexural stiffness of the medical device.

Description

Technical Field

[0001] The field of application relates to medical devices, and more particularly, to guidewires and catheters. Background Art

[0002] In the medical field, guidewires are used to access passages in a patient's body. In some cases, it may be desirable for the guidewire to have good torqueability, which allows a torque motion applied at the proximal end of the guidewire about the longitudinal axis of the guidewire to cause a corresponding twisting motion at the distal end of the guidewire.

[0003] In addition, it may be desirable for the distal segment of the guidewire to maintain a certain curved shape during use. This allows the distal segment of the guidewire to enter certain passages in the patient's body that have specific geometries. If the distal segment of the guidewire does not maintain its curved shape during use, it may not be able to enter the target passage.

[0004] In addition, it may be desirable for the guidewire to have a soft distal section. This prevents the guidewire from causing harm to the patient and also allows the guidewire to flex or bend elastically as it advances through passages having different shapes within the patient's body.

[0005] However, it is difficult for guidewire to achieve all the above-mentioned desired features. A guidewire may have a soft distal segment, but such a guidewire may have poor shape retention and may have poor twist control at the distal segment. On the other hand, a guidewire may have good shape retention and good twist control at the distal segment. However, such a guidewire may have a rigid distal segment. The above-mentioned desired features are difficult to achieve together, because the soft distal segment of the guidewire can not achieve good twist control usually due to the flexibility of the material used to make the distal segment. In addition, the material used to make the soft distal guidewire segment may not be able to make the distal guidewire segment keep its shape during use.

[0006] One or more of the above-described technical challenges similarly apply to catheters. Summary of the invention

[0007] A medical device comprises: an elongated member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip located at or connected to the distal end of the elongated member; and a radiopaque coil connected to the elongated member; wherein the radiopaque coil is formable and has shape-retaining properties, and wherein the bending stiffness of the formable radiopaque coil with shape-retaining properties is at least 10% of the bending stiffness of the medical device.

[0008] Optionally, the bending stiffness of the formable radiopaque coil is at least 20% of the bending stiffness of the medical device.

[0009] Optionally, the formable radiopaque coil having shape retaining properties is made of a material having an elastic modulus of at least 3E7 psi.

[0010] Optionally, the formable radiopaque coil with shape-retaining properties is made of molybdenum-rhenium (MoRe) or other molybdenum alloys, or of tungsten, tungsten-rhenium (WRe) or other tungsten alloys.

[0011] Optionally, the radiopaque coil is configured to help maintain the shape of the medical device.

[0012] Optionally, the bending stiffness of the radiopaque coil is greater than the bending stiffness of a coil of the same size and shape as the radiopaque coil but made of platinum or a platinum alloy.

[0013] Optionally, the radiopaque coil is heat treated to optimize the formability and shape retention characteristics of the radiopaque coil.

[0014] Optionally, the medical device is a guidewire.

[0015] Optionally, the elongate member is a shaft, and wherein the radiopaque coil surrounds at least a portion of the shaft. Optionally, the medical device further comprises a sheath disposed around the radiopaque coil.

[0016] Optionally, the shaft comprises a flat portion. Optionally, the shaft comprises a tapered portion adjacent the flat portion.

[0017] Optionally, the shaft comprises a cylindrical portion or another flat portion adjacent to the tapered portion.

[0018] Optionally, the medical device is a catheter.

[0019] Optionally, the elongate member is a tubular member, and wherein the radiopaque coil is coupled to the tubular member.

[0020] Optionally, a radiopaque coil is disposed circumferentially around the tubular member, or distally of the tubular member.

[0021] Optionally, the blunt tip comprises a linear surface at the distal end of the elongate member.

[0022] A guidewire comprises: a shaft having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip coupled to the distal end of the shaft; and a radiopaque coil disposed around at least a portion of the shaft; wherein the radiopaque coil is formable and has shape-retaining properties; and wherein the bending stiffness of the formable radiopaque coil having the shape-retaining properties is at least 10% of the bending stiffness of the guidewire.

[0023] A catheter comprises: a tubular member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; and a radiopaque coil connected to the tubular member; wherein the radiopaque coil is formable and has a shape-retaining property; and wherein the bending stiffness of the formable radiopaque coil with the shape-retaining property is at least 10% of the bending stiffness of the catheter.

[0024] Other and further aspects and features will be apparent from reading the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings illustrate the design and utility of the embodiments, wherein similar elements are represented by common reference numerals. These drawings are not necessarily drawn to scale. In order to better understand how to obtain the above and other advantages and purposes, a more specific description of the embodiments shown in the drawings will be provided. These drawings depict only exemplary embodiments and are therefore not to be considered as limiting the scope of the claims.

[0026] Figure 1 A guidewire with a radiopaque coil is shown.

[0027] Figure 2 Shows Figure 1 A variation of the guidewire in FIG. 1 is shown, which specifically shows a guidewire with an expandable structure.

[0028] Figure 3 Shows Figure 1 A variation of the guidewire in FIG. 1 is shown, which specifically shows a guidewire with a radiopaque coil that is implemented as part of a sheath.

[0029] Figure 4 A technique for securing a radiopaque coil to the shaft of a guidewire is shown.

[0030] Figure 5 A diagram is shown which illustrates stress-strain curves for different corresponding materials.

[0031] Figure 6 The radiopaque properties of different corresponding materials are shown.

[0032] Figure 7 A catheter with a radiopaque coil is shown.

[0033] Figure 8 Shows Figure 7 Variations of the catheter in.

[0034] Fig. 9 Shows Figure 7 Other variations of the catheter. DETAILED DESCRIPTION

[0035] Various embodiments will be described below with reference to the accompanying drawings. It should be noted that the drawings are not drawn to scale, and throughout the drawings, elements with similar structures or functions are represented by the same reference numerals. It should also be noted that the drawings are intended only to facilitate the description of the embodiments. They are not intended to be an exhaustive description of the invention or to limit the scope of the invention. In addition, the embodiments shown do not need to have all the aspects or advantages shown. The aspects or advantages described in conjunction with a specific embodiment are not necessarily limited to that embodiment, and may be practiced in any other embodiment (even if not shown or not so explicitly described).

[0036] Figure 1 A guidewire 100 according to some embodiments is shown. The guidewire 100 includes a shaft 110 having a proximal end 112, a distal end 114, and a body 116 extending from the proximal end 112 to the distal end 114. The body 116 of the shaft 110 includes a distal segment 120 having a plurality of different cross-sections along the length of the distal segment 120. At least an outer portion 130 of the body 116 proximal to the distal segment 120 is made of a material having a shear modulus of at least 13000 ksi. By way of non-limiting example, the material of the outer portion 130 of the body is a molybdenum-rhenium alloy or a tungsten-rhenium alloy.

[0037] In other embodiments, the outer portion 130 of the body 116 can be made of a material having a shear modulus less than 13,000 ksi. Additionally, in other cases, the material of the outer portion 130 can be other than molybdenum-rhenium alloy or tungsten-rhenium alloy.

[0038] In the illustrated embodiment, the shaft 110 includes a proximal section 300 made of a first material, and the distal section 120 is made of a second material different from the first material. In some embodiments, the proximal section 300 can be made of a molybdenum-rhenium alloy or a tungsten-rhenium alloy. In addition, in some embodiments, the distal section 120 can be made of nitinol, stainless steel, or a cobalt-chromium alloy (e.g., MP35N alloy).

[0039] The proximal segment 300 may be attached to the distal segment 120 via an adhesive, welding, a mechanical connector, or fusion.

[0040] In other embodiments, the proximal segment 300 and the distal segment 120 can be made of the same material. In one implementation, the segment 300 and the distal segment 120 can have a unitary configuration and can be made of the same material.

[0041] As shown, the distal segment 120 includes a first portion 301, a second portion 302, a third portion 304, a fourth portion 306, and a fifth portion 308. The cross-sectional dimensions of the fifth portion 308 are smaller than the cross-sectional dimensions of the third portion 304, and the smaller cross-sectional dimensions of the fifth portion 308 transition to the larger cross-sectional dimensions of the third portion 304 via the fourth (middle) portion 306. Similarly, the cross-sectional dimensions of the third portion 304 are smaller than the cross-sectional dimensions of the first portion 301, and the smaller cross-sectional dimensions of the third portion 304 transition to the larger cross-sectional dimensions of the first portion 301 via the second (middle) portion 302. This configuration is advantageous because it provides a gradually softer section in the direction from the proximal to the distal side. Therefore, the distal segment 120 is softer than the rest of the body 116 and can bend or bend more easily, wherein the distal portion 308 provides the softest section. In other embodiments, the distal segment 120 may include more or fewer sections than the above sections. In other embodiments, segment 120 may have the same cross-sectional size and / or cross-sectional shape along its entire length.

[0042] As shown, the inner portion 330 of the body 116 near the segment 120 and the outer portion 300 of the body 116 near the segment 120 are made of the same material (as shown in the shaded cross section). In one implementation, the outer portion 300 and the inner portion 330 of the body 116 are made of the same raw material (e.g., molybdenum-rhenium alloy, tungsten-rhenium alloy, etc.) so that they have a monolithic configuration. In other embodiments, the outer portion 300 and the inner portion 330 can be made of other materials. In addition, in other embodiments, the outer portion 300 and the inner portion 330 can be made of different corresponding materials.

[0043] In some embodiments, the portion 308 of the segment 120 can be compressed to form the elongated cross-sectional shape of the portion 308. For example, in one implementation, the portion 308 can have a circular cross-sectional shape, and the portion 308 of the segment 120 can be compressed into a planar structure having an elongated cross-sectional shape (e.g., a substantially rectangular shape) or any other non-circular cross-sectional shape. This feature is advantageous because it provides a bias in the bending direction of the portion 308. In addition, the elongated cross-sectional shape is advantageous because it allows the portion 308 of the segment 120 to have sufficient flexibility for bending in one plane while having sufficient cross-sectional area to achieve the desired tensile strength. In some embodiments, the compression of the portion 308 can be achieved by pressing (e.g., stamping, rolling, etc.) the portion 308. In other embodiments, the portion 308 of the segment 120 may not be compressed and / or may have a non-elongated cross-sectional shape. For example, in other embodiments, the portion 308 of the segment 120 may have a circular cross-sectional shape, a square cross-sectional shape, etc.

[0044] In the illustrated embodiment, the guidewire 100 also includes a sleeve 180 disposed around the distal end 114 of the shaft 110. As shown, the sleeve 180 has a blunt end 182, or is coupled to the blunt end 182. The distal end 114 of the shaft 110 is also coupled to the blunt end 182. The sleeve 180 can be any tubular member and can be made of any material, such as metal, polymer, etc. In some embodiments, the sleeve 180 can be made of nitinol. The sleeve 180 can have a plurality of slots and / or openings to increase the flexibility of the sleeve 180. By way of non-limiting example, the sleeve 180 can be implemented using a slotted hypotube, a coiled sleeve, a tungsten-containing polymer sleeve, or a combination thereof.

[0045] In one specific implementation, the proximal segment 300 is made of a molybdenum-rhenium alloy, and the distal segment 120 is made of nitinol. In another specific implementation, the proximal segment 300 is made of a molybdenum-rhenium alloy, and the distal segment 120 is made of stainless steel or a cobalt-chromium alloy (e.g., MP35N alloy). In both embodiments, the distal segment 120 provides the guide wire 100 with anti-kinking properties and a soft distal end, while the proximal segment 300 provides the desired pushability and the desired twist control. The distal segment 120 can be formable during use and provide the desired shape retention capability (e.g., with or without the aid of a ductile structure 230). In addition, due to its relatively high shear modulus, the molybdenum-rhenium alloy proximal segment 300 provides the desired twist control. In addition, due to the axial stiffness of the molybdenum-rhenium alloy segment 300, the guide wire 100 also has the desired pushability. In some cases, the proximal segment 300 and the distal segment 120 can be made of one or more materials having one or more corresponding elastic moduli to provide the device with a desired bending stiffness.

[0046] like Figure 1 As shown in , the guidewire 100 also includes a coil 190 disposed inside the sleeve 180. As shown in the figure, one end of the coil 190 is connected (e.g., directly or indirectly fixed, extended, etc.) to the end 182. In other embodiments, the proximal end of the coil 190 can be connected (e.g., extended from it, directly or indirectly fixed, etc.) to the distal segment 120 (e.g., connected to any position near the portion 308, such as connected to the portion 306, the portion 304 or the portion 302, etc.). The fixation can be achieved using adhesives, welding, mechanical connectors, fusion, etc. In other embodiments, the coil 190 can also be connected to the wall of the sleeve 180. In other embodiments, at least a portion of the sleeve 180 can be formed by the coil 190 ( Figure 3 ) is formed. In these cases, the cross-sectional dimensions of the coil 190 correspond to (eg, are the same as) the cross-sectional dimensions of the sleeve 180. In other embodiments, the coil 190 may form an integral part of the sleeve 180.

[0047] In the illustrated embodiment, the coil 190 is made of molybdenum rhenium (MoRe). This allows the coil 190 to act as a radiopaque coil during a medical procedure. The coil 190 made of MoRe also provides the coil 190 with desirable stiffness and shape retention properties. During a medical procedure, after the distal portion of the guidewire 100 is bent, the shape retention properties of the coil 190 help the distal portion of the guidewire 100 maintain the bent shape.

[0048] In some cases, the cross-sectional dimensions (e.g., diameter) of the wire constituting coil 190 can be anywhere between 0.001 inches and 0.005 inches. Additionally, the length (unwound length) of the wire constituting coil 190 can be anywhere between 5 cm and 150 cm. In other cases, the cross-sectional dimensions of the wire constituting coil 190 can be less than 0.001 inches or greater than 0.005 inches, and / or the unwound length of the wire can be greater than 20 cm.

[0049] In some cases, the length of coil 190 can be anywhere between 1 cm and 10 cm. In addition, the outer diameter of coil 190 can be anywhere between 0.004 inches and 0.05 inches, and more preferably anywhere between 0.006 inches and 0.02 inches, and more preferably anywhere between 0.008 inches and 0.01 inches.

[0050] In some cases, each turn of coil 190 may be in contact with a corresponding adjacent (neighboring) turn. In other cases, coil 190 has an open pitch, wherein the spacing between adjacent turns of coil 190 may be anywhere between 0.0001 inches to 0.002 inches, or greater.

[0051] It should be noted that the coil 190 is advantageous because it holds its shape better than a cylindrical or flat solid section. This is due to the Bauschinger effect, whereby when the coil 190 is formed, it is primarily subjected to shear strain, and this strain is evenly distributed along the entire length of the wire forming the coil 190. The Bauschinger effect becomes more pronounced with a greater degree of cold working. Since the coil 190 is subjected to a relatively small amount of cold working during forming (e.g., compared to a stamped tip), the coil 190 has a stronger shape retention. In addition, in some cases, the stiffness of the coil 190 may only account for a small proportion of the stiffness of the entire distal tip. Therefore, the coil 190 forms well and has less impact on the system behavior. In some cases, the coil 190 can be made more rigid, while the other components of the guidewire 100 can be made softer, thereby achieving better tip shape retention (TSR). The shear modulus and elastic modulus of MoRe are at least twice that of Pt alloys.

[0052] The stiffness (e.g., bending stiffness) of the coil 190 can be adjusted by incorporating different amounts of rhenium (Re) into the alloy MoRe. By way of non-limiting example, the MoRe alloy may have 47%, 47.5%, 41%, 25% rhenium by weight. In some cases, the amount of rhenium in the MoRe alloy is at least 15% by weight, and preferably at least 20%, and more preferably at least 30% (e.g., any value between 30% and 60%).

[0053] One technique for making the coil 190 is to wind a wire or elongated element made of MoRe (or any other desired material described herein) onto a mandrel. The cross-sectional shape of the elongated element (e.g., wire) constituting the coil 190 can be circular, rectangular, elliptical, or any other shape, and the resulting coil 190 can be modified by removing or adding material or axial stretching or compression after winding. Another technique for making the coil 190 is to cut (e.g., laser cutting) through the wall of a tube made of MoRe or any other desired material described herein to make the coil. Therefore, as used in this specification, the term "coil" is not limited to a wire wound into a coil configuration. Optionally, the coil 190 can be annealed after winding the guide wire to alleviate the cold working caused during winding. In addition, optionally, the coil 190 can be treated with one or more hardening techniques (such as configuring wire stretching parameters, heat treatment, shot peening, etc.) to achieve the desired stiffness of the coil 190.

[0054] exist Figure 1In the illustrated embodiment of the present invention, the distal portion 308 of the segment 120 is ductile. Therefore, the distal portion 308 of the segment 120 can be bent to form a curved shape. The distal portion 308 is made of a material that allows it to maintain a curved shape after the distal portion 308 of the segment 120 is bent. In these cases, the coil 190 is also ductile and bendable, so that the coil 190 and the distal portion 308 of the segment 120 can be bent together. The coil 190 also maintains its curved shape, so that the distal portion 308 of the segment 120 and the coil 190 can maintain the curved shape of the guidewire 100 together. In some embodiments, the distal portion 308 of the segment 120 cannot provide sufficient bending stiffness alone. In these cases, the coil 190 can provide additional bending stiffness. It is desirable that the coil 190 provides a considerable portion (e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70% or more) of the total bending stiffness, so that its shape retention has a significant impact on the system. The stiffness of the coil 190 can be adjusted by changing the coil pitch, the coil wire diameter, the coil wire elastic modulus, the material composition or any combination of the above. It should be noted that because the wire of the coil 190 is twisted when the coil 190 is bent, it is not easy to achieve the desired bending stiffness of the coil 190. By utilizing the materials and techniques described herein to manufacture the coil 190, the desired bending stiffness of the coil 190 can be achieved.

[0055] In other embodiments, the distal portion 308 may be made of a material that does not have sufficient shape-retaining capabilities. In these cases, the coil 190 will provide shape-retaining properties to the guidewire 100. Thus, the coil 190 may: (1) assist the distal portion 308 in providing the desired shape-retaining properties to the guidewire 100; or (2) provide at least a majority (e.g., all) of the shape-retaining properties to the guidewire 100.

[0056] In other embodiments, the distal portion 308 and the coil 190 together may not provide sufficient shape retention for the guidewire 100. In these cases, the guidewire 100 may also include a Figure 2 ) of the ductile structure 230 (e.g., a flat plate, a wire, a shaped band, etc.). The ductile structure 230 can be located inside the sleeve 180. During use, the ductile structure 230 can be bent to form a curved shape and is configured to maintain the curved shape after the ductile structure 230 is bent.

[0057] It should be noted that the guide wire 100 is not limited to Figure 1 to Figure 2, and guidewire 100 may have other configurations in other embodiments. In other embodiments, guidewire 100 may include more than two segments. For example, in other embodiments, guidewire 100 may include three or more segments connected in series along the longitudinal axis of guidewire 100. In addition, in some embodiments, at least one segment of guidewire 100 may have multiple layers or a single layer.

[0058] The guidewire 100 is advantageous because it provides an optimal combination of formability, shape retention and twist control. Since the coil 190 is constructed using MoRe, the resulting guidewire 100 can have a small profile. Therefore, the guidewire 100 can be used to enter smaller blood vessels (such as distal blood vessels in the brain), thereby reaching more aneurysms that were previously inaccessible. The coil 190 made of MoRe allows the distal portion of the guidewire 100 to be shaped during use and provides the desired shape retention (without the aid of a ductile structure). However, in other embodiments, as similarly discussed, the guidewire 100 may also optionally include a ductile structure to enhance the shape retention. In addition, the distal portion of the guidewire 100 provides the guidewire 100 with desired twist control, kink resistance, and a soft distal end.

[0059] The material used to make the coil 190 is not limited to MoRe, and in other cases, the coil 190 may be made of other materials. For example, in other cases, the coil 190 may be made of a combination of MoRe and other alloying elements (such as Zr and / or Hf). In other cases, the coil 190 may be made of tungsten-rhenium or tungsten and other alloying elements (such as Zr and / or Hf). Any of these materials may allow the radiopaque coil 190 to achieve a desired bending stiffness. In other cases, the coil 190 may also be made of other materials than the above examples.

[0060] In some cases, the elastic modulus of the material that allows the radiopaque coil 190 to achieve the desired bending stiffness is at least 3E7 psi, and preferably 4E7 or higher. The desired bending stiffness of the coil 190 is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70% or more of the bending stiffness of the guidewire 100.

[0061] Furthermore, in some cases, the material of coil 190 may exhibit similar or greater x-ray attenuation than Pd (of the same thickness as the material) at x-ray energy levels suitable for imaging. m The X-ray attenuation A exhibited by Pd pd The difference does not exceed 20% (i.e., 0.8A pd <=Am <=1.2A pd ), the x-ray attenuation exhibited by the material of coil 190 can be considered to be "similar" to the x-ray attenuation exhibited by Pd of equal thickness.

[0062] In addition, it should be noted that the material for manufacturing the shaft 110 of the guide wire 100 should not be limited to the described examples, and the shaft 110 can be made of other materials in other embodiments. For example, in other embodiments, the shaft 110 of the guide wire 100 can be made of other materials, as long as the desired torsion control can be achieved. In other embodiments, the shaft 110 can be made of any material having a Young's modulus (under annealing conditions) of at least 6000 ksi, or more preferably at least 30000 ksi, or even more preferably at least 40000 ksi. In addition, in other embodiments, the shaft 110 can be made of any material having an ultimate tensile strength of at least 100 ksi, and more preferably at least 200 ksi, and even more preferably at least 300 ksi. By way of non-limiting example, the specific materials that can be used include but are not limited to Mo-47.5Re, W-25Re, SS304, etc.

[0063] In some cases, the tensile strength of MoRe can be almost 1M ksi. This can be acceptable for the shaft 110 used to construct the guidewire 100. However, for the coil 190, it will be desirable to utilize a class of MoRe or other materials with lower tensile strength (and therefore, lower yield strength) to achieve formability. In some cases, the ultimate tensile strength (UTS) can be in the range of 200 kpsi to 400 kpsi. In some cases, the UTS and yield strength of the coil 190 can be reduced by inducing a lower degree of cold working during the stretching of the wire. Subsequent heat treatment (annealing) can also be utilized to reduce the UTS of the coil 190.

[0064] In addition, it should be noted that the shaft 110 of guide wire 100 can have different sizes in different embodiments. For example, in some embodiments, the total length of the shaft 110 of guide wire 100 can be any value between 50 inches and 100 inches, such as any value between 70 inches and 90 inches in length. In addition, in some embodiments, the length of distal segment 120 can be any value between 5 inches and 30 inches, such as any value between 10 inches and 25 inches in length, or any value between 12 inches and 20 inches in length. In addition, in some embodiments, the length of distal portion 308 can be any value between 0.3 inches and 1 inch, such as any value between 0.5 inches and 0.8 inches in length. In some embodiments in which distal portion 308 is stamped, a part of the stamped distal portion can have a constant width, wherein the longitudinal length of the part can be at least 0.3 inches, such as at least 0.4 inches. Additionally, in some embodiments, the cross-sectional dimensions (e.g., diameter) of the distal segment 120 can be any value between 0.00157 inches and 0.0197 inches (0.04 mm to 0.5 mm), and the cross-sectional dimensions (e.g., diameter) of the distal portion 308 can be any value between 0.000157 inches and 0.00394 inches (0.004 mm to 0.1 mm). In other embodiments, the dimensions of the distal segment 120 and / or the distal portion 308 can differ from the dimensions described above.

[0065] Furthermore, the number of different cross-sections along the length of the distal segment 120 is not limited to the examples described above. In other embodiments, the number of different cross-sections along the length of the distal segment 120 can be more or less than described herein.

[0066] Additionally, in one or more embodiments described herein, as similarly discussed, a portion of segment 120 may have a flat portion. For example, portion 308 (in Figure 1 or Figure 2 In some embodiments, the flat portion of segment 120 may be compressed (e.g., stamped, rolled, etc.) to form a flat portion. In some embodiments, the flat portion of segment 120 may include one or more openings extending through the thickness of the flat portion. This feature is advantageous because it can help the guidewire 100 achieve a soft distal end without affecting other properties (such as formability, tensile strength, and / or shape retention of the guidewire 100).

[0067] In addition, it should be noted that the manner in which the coil 190 is fixed to the shaft 110 is not limited to the described example. In other embodiments, the coil 190 may be fixed to the shaft 110 in other ways. For example, Figure 4As shown in , in some embodiments, the coil 190 of the guidewire 100 can be a radiopaque coil 190 that surrounds at least a portion of the segment 120 of the shaft 110 of the guidewire 100. The portion of the segment 120 has two opposing sides 800, 802, and a notch 810 is provided along each side of the two opposing sides to allow the radiopaque coil 190 to be screwed on the portion of the segment 120. In some embodiments, the portion of the segment 120 surrounded by the radiopaque coil 190 can be a flat portion. In these cases, the notch 810 can be a groove extending through the thickness of the flat portion. In some embodiments, the notch 810 can be implemented as a notch. In other embodiments, the portion of the segment 120 surrounded by the coil 190 can be another portion of the segment 120 near the flat portion 308. In other embodiments, the segment 120 surrounded by the radiopaque coil 190 may not be any flat portion. Alternatively, the segment 120 surrounded by the radiopaque coil 190 can be a non-flat portion of the core wire or shaft. Figure 4 The technique for attaching the coil 190 to the segment 120 shown in is advantageous because it provides mechanical interaction between the segment 120 and the coil 190, and it also saves space within the outer distal sleeve of the guidewire 100. This is also advantageous because the strength of the bond is derived from the mechanical interface between the segment 120 and the coil 190, rather than the adhesive interface. In some cases, the segment 120 can be manufactured by laser profiling a stamped component, which allows the coil 190 to be helically wound thereon.

[0068] In any of the embodiments described herein, the guidewire 100 can be provided as part of a medical device. For example, the medical device can include a catheter and the guidewire 100, wherein the catheter includes a lumen for accommodating the guidewire 100. By way of non-limiting example, the medical device can be a microcatheter, a balloon catheter, a stent delivery catheter, a catheter for removing a blood vessel blockage, a delivery catheter for the guidewire 100, and the like.

[0069] In a method of using guide wire 100, the doctor first bends the distal segment of guide wire 100 into a desired shape according to the geometry of the anatomical structure into which guide wire 100 will enter. For example, the distal segment of guide wire 100 can be bent into a shape having an L-shaped shape, a C-shaped shape, a U-shaped shape, an S-shaped shape, a shape having two or more curves in different planes, etc. Then, guide wire 100 is placed in a delivery catheter. Then, an incision is formed on the patient's skin. Through this incision, the delivery catheter and the guide wire 100 therein are inserted and enter the blood vessel in the patient's body. The delivery catheter and guide wire 100 can be advanced distally until the distal end of guide wire 100 and / or delivery catheter reaches the target site. The target site can be any part of the patient's body, such as blood vessels in the limbs, trunk, neck, head, etc. When the delivery catheter advances distally, the delivery catheter accommodates guide wire 100. When the delivery catheter arrives at a position in the patient's body that requires the distal segment of the guide wire 100 to be in a curved shape to enter, at least a portion of the distal segment can be deployed outside the delivery catheter so that the distal segment presents its curved shape. A torque can be applied to the guide wire 100 to guide the curved shape in the direction of the desired entry. The curved shape of the distal segment of the guide wire 100 turns the guide wire 100 to the desired direction, thereby allowing the guide wire 100 and the delivery catheter to advance to the desired channel distally. The guide wire 100 described herein is advantageous because it allows the distal segment of the guide wire 100 to maintain a curved shape, so that even after the distal segment travels along different paths in a blood vessel with different curvatures (or even after the curved distal segment is placed in a tube such as a delivery tube), the curved shape will not return to the pre-bent configuration. The guide wire 100 is also advantageous because due to the enhanced torsion control of the guide wire 100, it allows the doctor to effectively apply torque to the guide wire 100, and allows the doctor to push the guide wire 100 distally in the patient's body without kinking.

[0070] The embodiments of the guidewire 100 described herein have a desired twist controllability, a desired shape retention capability, a desired pushability, or any combination thereof. In some embodiments, if a twisting motion or torque motion is applied at the proximal end around the longitudinal axis of the guidewire 100 to rotate the proximal end of the guidewire 100 (or shaft 110) by an angle P, the distal end of the guidewire 100 will be rotated by an angle D, which is at least 80% of P, or more preferably at least 90% of P, or even more preferably at least 95% of P (e.g., 100% of P, which means that the distal end of the guidewire 100 has a 1:1 response to the torque applied at the proximal end of the guidewire 100), then the guidewire 100 is considered to have achieved the desired twist controllability. In addition, in some embodiments, if a curved segment having a curvature can maintain at least 70% of the curvature after the curved segment is placed in a tube and pushed back from the tube, or more preferably maintain at least 80% of the curvature, and even more preferably maintain at least 90% of the curvature, then the guidewire 100 is considered to have achieved the desired shape retention capability. Furthermore, in some embodiments, the desired pushability may be achieved if the guidewire 100 does not kink while being advanced within the vessel.

[0071] It should be noted that it is advantageous to use MoRe to make the radiopaque coil 190. The elastic modulus of MoRe is higher than that of platinum or platinum alloys (see Figure 5 ) has an elastic modulus 2.5 to 3 times greater than that of a circular wire made of Mo41Re. In the figure, curve (a) is a stress-strain curve for a circular wire with a diameter of 25 um made of Mo41Re, curve (b) is a stress-strain curve for a circular wire with a diameter of 25 um made of W25Re, and curve (c) is a stress-strain curve for a circular wire with a diameter of 25 um made of Mo47Re. The guidewire 100 may need to have a low profile (e.g., diameter), which limits the size of the wire that can be used to make the non-radiopaque coil 190 of the guidewire 100, limits the stiffness of such a coil 190, and limits the usefulness of the coil 190 to help the guidewire 100 maintain a distal bend shape. Using a MoRe material with higher stiffness or other materials described herein to make the non-radiopaque coil improves the shape retention of the guidewire compared to traditional materials.

[0072] Furthermore, in some embodiments, by appropriately selecting heat treatment parameters, the yield strain of the material (e.g., MoRe) in the radiopaque coil 190 can be adjusted so that the curvature of the coil 190 can correspond to the curvature of the core (e.g., shaft 110) during the forming process. Alternatively or additionally, the material in the radiopaque coil 190 can also be adjusted so that the formability and / or shape retention properties of the coil 190 (or guidewire / catheter) can be improved (e.g., optimized). In some cases, heat treatment after coil winding can help eliminate cold work hardening that may occur during coil winding.

[0073] Additionally, using MoRe or other materials described herein to make coil 190 is advantageous because it can have better shape retention than a core tape of similar shape due to reduced effects of the Bauschinger effect. The Bauschinger effect is the tendency of a plastically deformed metal to deform plastically at lower stress levels in a direction opposite to the direction of initial deformation. The extent of this effect is proportional to the extent of the initial plastic deformation. Since the deformation of the coil (in a twisted state) is distributed over a greater length of the coil wire in order to achieve the same curvature in the coil as the core tape, the effects of the Bauschinger effect in the coil structure should be reduced.

[0074] Furthermore, the use of the materials described herein (e.g., MoRe) to manufacture the coil 190 is also advantageous because it provides sufficient radiopacity for use in medical procedures. The attenuation of an alloy is the sum of the individual coefficients of the various elements multiplied by the weight fraction present in the alloy. Figure 6 As shown in , in the relevant x-ray energy range, the attenuation of Mo41Re is close to that of Pt and Au, and slightly better than that of Pd and Ta, which are sometimes used in radiopaque elements.

[0075] Coils made of the materials described herein (e.g., MoRe, WRe, etc.) are not limited to use in guidewires and are made for use in other types of medical devices. In other embodiments, coils made of MoRe, WRe, etc. may be part of a push wire or a delivery wire. In other embodiments, coils made of MoRe, WRe, etc. may be part of a catheter (e.g., a delivery catheter, a diagnostic catheter, a therapeutic catheter, a balloon catheter, etc.).

[0076] Figure 7A catheter 700 is shown with a coil 702 made of MoRe, WRe, or another material described herein. The catheter 700 can be a delivery catheter configured to deliver items such as drugs, medications, medicaments, implants (e.g., vascular occlusion devices, stents, etc.), biopsy devices, therapeutic devices, etc. In other embodiments, the catheter 700 can be a delivery catheter configured to obtain a biopsy or tissue sample from a patient and deliver it to a container outside the patient's body. In some embodiments, the catheter 700 can optionally also include an inflatable balloon.

[0077] As shown, the catheter 700 includes a tubular member 710 having a proximal end 712, a distal end 714, and a body 716 extending from the proximal end 712 to the distal end 714. The coil 702 is a radiopaque coil made of MoRe, WRe, or another material described herein, and is coupled to the tubular member 710. The stiffness of the radiopaque coil 702 is greater than the stiffness of a coil of the same size and shape but made of platinum or a platinum alloy. In addition, at least a portion of the radiopaque coil 702 is configured to have a curvature corresponding to the curvature of a portion of the body 716 of the tubular member 710.

[0078] In some embodiments, the radiopaque coil 702 is optionally formable and has shape retaining properties.

[0079] In the above-described embodiment, the coil 702 is located within the wall of the tubular member 710. In other embodiments, the coil 702 can be disposed outside the tubular member 710 and surround the tubular member 710 ( Figure 8 In another embodiment, the coil 702 may be disposed in the tubular member 710 ( Fig. 9 ). In these cases, the coil 702 can be fixed to the tubular member 710 by an adhesive and / or by a sleeve that engages both the coil 702 and the tubular member 710. The sleeve can be disposed on the inner surface of the tubular member 710 and the inner surface of the coil 702. Alternatively, the sleeve can be disposed on the outer surface of the tubular member 710 and the outer surface of the coil 702. In other embodiments, at least a portion of the tubular member 710 and at least a portion of the coil 702 can be disposed inside the sleeve.

[0080] The following items are exemplary features of the embodiments described herein. Each item can be an embodiment itself or can be a part of an embodiment. In an embodiment, one or more items described below can be combined with other items.

[0081] Item 1: A medical device comprising: an elongated member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip located at or connected to the distal end of the elongated member; and a radiopaque coil connected to the elongated member; wherein the radiopaque coil is formable and has shape-retaining properties, and wherein the bending stiffness of the formable radiopaque coil with shape-retaining properties is at least 10% of the bending stiffness of the medical device.

[0082] Item 2: The bending stiffness of the formable radiopaque coil is at least 20% of the bending stiffness of the medical device.

[0083] Item 3: A formable radiopaque coil having shape-retaining properties is made from a material having an elastic modulus of at least 3E7 psi.

[0084] Item 4: A formable radiopaque coil with shape retention properties is made of molybdenum-rhenium (MoRe) or other molybdenum alloys.

[0085] Item 5: A formable radiopaque coil with shape-retaining properties made of tungsten, tungsten-rhenium (WRe), or other tungsten alloys.

[0086] Item 6: The radiopaque coil is configured to help maintain the shape of the medical device.

[0087] Item 7: The bending stiffness of the radiopaque coil is greater than the bending stiffness of a coil of the same size and shape as the radiopaque coil but made of platinum or a platinum alloy.

[0088] Item 8: The radiopaque coil is heat treated to optimize the formability and shape retention characteristics of the radiopaque coil.

[0089] Item 9: The medical device is a guidewire.

[0090] Item 10: The elongated member is a shaft, and wherein the radiopaque coil surrounds at least a portion of the shaft.

[0091] Item 11: The medical device also includes a sleeve disposed around the radiopaque coil.

[0092] Item 12: The shaft includes a flat portion.

[0093] Item 13: The shaft includes a tapered portion adjacent the flat portion.

[0094] Item 14: The shaft includes a cylindrical portion or another flat portion adjacent to the tapered portion.

[0095] Item 15: The medical device is a catheter.

[0096] Item 16: The elongated member is a tubular member, and wherein the radiopaque coil is coupled to the tubular member.

[0097] Item 17: A radiopaque coil is disposed circumferentially around the tubular member, or is located distally of the tubular member.

[0098] Item 18: The blunt tip includes a straight surface at the distal end of the elongated member.

[0099] Item 19: A guidewire comprising: a shaft having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip connected to the distal end of the shaft; and a radiopaque coil disposed around at least a portion of the shaft; wherein the radiopaque coil is formable and has shape-retaining properties; and wherein the bending stiffness of the formable radiopaque coil having shape-retaining properties is at least 10% of the bending stiffness of the guidewire.

[0100] Item 20: A catheter comprising: a tubular member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; and a radiopaque coil connected to the tubular member; wherein the radiopaque coil is formable and has shape-retaining properties; and wherein the bending stiffness of the formable radiopaque coil with shape-retaining properties is at least 10% of the bending stiffness of the catheter.

[0101] Although specific embodiments have been shown and described, it will be understood that the claimed invention is not intended to be limited to the preferred embodiments, and it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the claimed invention. Therefore, the description and drawings are to be regarded as illustrative rather than restrictive. The claimed invention is intended to cover alternatives, modifications, and equivalents.

Claims

1. A medical device comprising: an elongated member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip located at or coupled to the distal end of the elongated member; as well as a radiopaque coil coupled to the elongated member; wherein the radiopaque coil is formable and has shape retaining properties, and wherein the formable radiopaque coil having shape retaining properties has a bending stiffness that is at least 10% of a bending stiffness of the medical device.

2. The medical device according to claim 1, wherein: The shapeable radiopaque coil may have a bending stiffness that is at least 20% of a bending stiffness of the medical device.

3. The medical device according to claim 1 or 2, wherein: The formable radiopaque coil having shape-retaining properties is made of a material having an elastic modulus of at least 3E7 psi.

4. The medical device according to any one of claims 1 to 3, wherein: The formable radiopaque coil having shape-retaining properties is made of molybdenum-rhenium (MoRe) or other molybdenum alloys.

5. The medical device according to any one of claims 1 to 3, wherein: The formable radiopaque coil having shape-retaining properties is made of tungsten, tungsten-rhenium (WRe), or other tungsten alloys.

6. The medical device according to any one of claims 1 to 5, wherein: The radiopaque coil is configured to help maintain a shape of the medical device.

7. The medical device according to any one of claims 1 to 6, wherein: The bending stiffness of the radiopaque coil is greater than the bending stiffness of a coil having the same size and shape as the radiopaque coil but made of platinum or a platinum alloy.

8. The medical device according to any one of claims 1 to 7, wherein: The radiopaque coil is heat treated to optimize the formability and shape retention characteristics of the radiopaque coil.

9. The medical device according to any one of claims 1 to 8, wherein: The medical device is a guidewire.

10. The medical device according to claim 9, wherein: The elongate member is a shaft, and wherein the radiopaque coil surrounds at least a portion of the shaft.

11. The medical device of claim 10, further comprising a sleeve disposed around the radiopaque coil.

12. The medical device according to claim 10, wherein: The shaft includes a flat portion.

13. The medical device according to claim 12, wherein: The shaft includes a tapered portion proximate the flat portion.

14. The medical device according to claim 13, wherein: The shaft includes a cylindrical portion or another flat portion adjacent to the tapered portion.

15. The medical device according to any one of claims 1 to 8, wherein: The medical device is a catheter.

16. The medical device according to claim 15, wherein: The elongated member is a tubular member, and wherein the radiopaque coil is coupled to the tubular member.

17. The medical device according to claim 16, wherein: The radiopaque coil is disposed circumferentially around the tubular member, or distally of the tubular member.

18. The medical device according to claim 15, wherein: The blunt tip includes a linear surface at the distal end of the elongated member.

19. A guide wire, comprising: a shaft having a proximal end, a distal end, and a body extending from the proximal end to the distal end; a blunt tip coupled to the distal end of the shaft; as well as a radiopaque coil disposed around at least a portion of the shaft; wherein the radiopaque coil is formable and has shape-retaining properties; and Wherein the bending stiffness of the formable radiopaque coil having shape-retaining properties is at least 10% of the bending stiffness of the guidewire.

20. A catheter, comprising: a tubular member having a proximal end, a distal end, and a body extending from the proximal end to the distal end; as well as a radiopaque coil coupled to the tubular member; wherein the radiopaque coil is formable and has shape-retaining properties; and wherein the bending stiffness of the formable radiopaque coil having shape retaining properties is at least 10% of the bending stiffness of the catheter.

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