Guidewire with reduced stiffness section - Patents.com

Abstract

The guidewire (100) comprises an elongate member (102) having a proximal portion and a distal portion (112). The distal portion (112) includes a distal curved portion (114) terminating at a distal tip (118) and a tapered region that reduces a cross-section from a larger cross-section to a smaller cross-section. The elongate member (102) further includes a plurality of flattened regions (120a, 120b) disposed at distinct locations along the elongate member. Each of the plurality of flattened regions (120a, 120b) is separated from one another by a non-flattened region (122), such that when a force is applied to the guidewire (100), the guidewire experiences a bend at the plurality of flattened regions (120a, 120b).

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to devices and methods for puncturing the septum of the heart. More particularly, the present disclosure relates to a guidewire configured to pierce the interatrial septum. [Background technology]

[0002] Medical guidewires are typically manufactured using a metallic core mandrel with a round (circular) cross section. To make the guidewire more flexible and less traumatic, the distal portion of the core wire is ground and tapered from a larger outer diameter to a smaller outer diameter. Additionally, the core mandrel may be shaped or curved to assume an atraumatic configuration, such as a J-shape, to reduce tissue trauma. In this configuration, the contact forces experienced by the guidewire upon tissue contact are distributed over a larger surface area.

[0003] To maintain the guidewire's curvature, the mandrel may be crushed or flattened. This work-hardens the metallic mandrel, which provides curve-maintaining properties and improves the atraumatic nature of the guidewire. However, when the mandrel is crushed or flattened, a bend point occurs where the cross section changes from a round or circular cross section to a crushed or flattened cross section. In other words, at the intersection of the circular cross section and the beginning of the flattened section, a bend point is formed or occurs when the guidewire is pressed against tissue. Thus, if the guidewire is roughly manipulated or subjected to significant force against tissue, the guidewire may become kinked or pinched at the bend point (excessive bending results in plastic deformation). In some instances, repeated kinking or pinching of the guidewire may cause the guidewire to break. Summary of the Invention

[0004] In one broad aspect of the disclosure, the guidewire comprises an elongate member having a proximal portion and a distal portion. The distal portion includes a distal curved portion terminating at a distal tip and a tapered region that reduces a cross-section from a larger cross-section to a smaller cross-section. The elongate member further includes a plurality of flattened regions disposed at discrete locations along the elongate member. Each of the plurality of flattened regions is separated from one another by a non-flattened region, such that when a force is applied to the guidewire, the guidewire experiences a bend at the plurality of flattened regions. [Brief description of the drawings]

[0005] In order that the invention may be readily understood, embodiments thereof are illustrated in the accompanying drawings. [Figure 1] FIG. 1 is a side view of one prior art embodiment of a guidewire. [Diagram 2] FIG. 1 is a side view of a prior art guidewire with a curved distal portion. [Diagram 3] FIG. 1 is a side view of a guidewire comprising multiple reduced stiffness sections and a curved distal section. [Figure 4] FIG. 4 is a side perspective view of the guidewire shown in FIG. 3. [Diagram 5] FIG. 1 is a front view of a guidewire with a radiopaque coil. [Figure 6] FIG. 1 is a side view of a guidewire with multiple tapered sections. [Figure 7A] 13 is a cross-sectional view of an alternative embodiment guidewire. [Figure 7B] 13 is a cross-sectional view of an alternative embodiment guidewire. [Figure 8A] FIG. 13 is a side view of an alternative embodiment of a guidewire having multiple coiled portions. [Figure 8B] FIG. 13 is a side view of an alternative embodiment of a guidewire having multiple coiled portions. [Figure 9A] 13 is a side view of an alternative embodiment of a guidewire having multiple reduced stiffness portions. FIG. [Figure 9B]13 is a side view of an alternative embodiment of a guidewire having multiple reduced stiffness portions. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] With specific reference now to the drawings in detail, it is emphasized that the details shown are by way of example and are for illustrative purposes only of certain embodiments of the invention. Before describing at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. It is also to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0007] As described further below, the present invention provides a guidewire with multiple crushed or flattened sections to provide enhanced curve maintenance and reduce the likelihood of kinking or breakage.

[0008] Referring now to prior art FIG. 1, a guidewire core mandrel 102 configured to puncture a target tissue (e.g., the septum of the heart) is depicted. The mandrel 102 may include multiple tapered sections separated by non-tapered regions. This configuration allows for greater flexibility in shorter lengths of the mandrel. The tapered sections and intermediate region may be formed by grinding the mandrel 102. The core mandrel 102 may include a first proximal tapered region 104 and a second intermediate tapered region 106. The guidewire 100 may further include a radiopaque coil 110 (not shown) and a coil stop 111. Transition regions 105a and 105b may be disposed between the tapered regions 104, 106. The transition regions 105a and 105b are regions of constant diameter.

[0009] Referring to Prior Art FIG. 2, guidewire 100 includes a curved distal region 114 configured to assume an atraumatic shape. Curved distal region 114 includes a straight portion 116 disposed distal to curve 114, thereby forming a J-shape and terminating at a distal tip 118. Curved distal region 114 extends the length of distal portion 112, which terminates at distal tip 118. Distal tip 118 is configured to pierce target tissue. Curved distal region 114 redirects distal tip 118 away from tissue during advancement, thereby preventing inadvertent damage to surrounding tissue.

[0010] To help maintain the curve, the distal portion 112 may be crushed or flattened. In some embodiments, the flattened region extends along the length of the distal portion 112. In alternative embodiments, the flattened region may be located at different locations along the guidewire 100 and does not necessarily extend the entire length of the distal portion 112. The point where the mandrel 102 changes from a circular cross section to a flattened cross section is the most flexible part. This creates a bend point at that location when a force is applied to the curved distal portion 112. This can cause the guidewire 100 to bend or pinch at that location, and may even break.

[0011] FIG. 3 shows a side view of a guidewire according to one embodiment of the present invention. Typically, the guidewire 100 can vary in length between 31.5 inches and 177.2 inches and tapers from a larger cross section to a smaller cross section. This results in the distal portion 112 having the smallest cross section and therefore is flexible and less traumatic when contacting tissue. The mandrel 102 can have a round or circular cross section with an outer diameter of 0.014 inches to 0.038 inches, or alternatively, the cross section of the mandrel can take any other shape. The mandrel 102 can include multiple tapered sections separated by non-tapered regions. This configuration allows for greater flexibility at shorter lengths of the mandrel. The tapered sections and intermediate region can be formed by grinding the mandrel 102. The core mandrel 102 may include a first proximal tapered region 104 and a second intermediate tapered region 106. The guidewire 100 may further include a radiopaque coil 110 (not shown) and a coil stopper 111. Transition regions 105a and 105b may be disposed between the tapered regions 104, 106 and the coil stopper 111. The transition regions 105a and 105b are regions of constant diameter. In one embodiment, the radiopaque coil 110 is disposed over the transition region 105b proximal to the coil stopper 111. Alternatively, the mandrel 102 may transition smoothly from a larger outer diameter to a smaller outer diameter.

[0012] The guidewire further includes a curved distal region 114. The curved distal region 114 may include a straight portion 116 disposed distal to the curve 114, thereby forming a J-shape and terminating at a distal tip 118. In an alternative embodiment, the distal curved portion 114 may be in the form of a pigtail curve. The guidewire 100 may be configured such that the distal portion 112 may assume a straight configuration when the guidewire 100 is constrained or placed within an auxiliary device. When the guidewire 100 is unconstrained, the guidewire 100 may assume a curved configuration. The curved distal region 114 extends the length of the distal portion 112, which terminates at a distal tip 118. The distal tip 118 may be a sharp tip that requires mechanical force to pierce the target tissue. The curved distal region 114 redirects the sharpened distal tip 118 away from tissue during advancement, thereby preventing inadvertent damage to surrounding tissue. The distal tip 118 can be configured to deliver energy to tissue. In one example, the distal tip 118 can be an electrode in electrical communication with an energy generator.

[0013] The mandrel 102 may include multiple tapered sections separated by non-tapered regions. This configuration allows for greater flexibility in shorter lengths of the mandrel. The tapered sections and intermediate regions may be formed by grinding the mandrel 102. The core mandrel 102 may include a first proximal tapered region 104 and a second intermediate tapered region 106. The guidewire 100 may further include a radiopaque coil 110 (not shown) and a coil stop 111. In one embodiment, the guidewire 100 may include multiple flattened portions 120a and 120b. The flattened portions 120a and 120b have a relatively lower stiffness than the unflattened mandrel 102. The flattened portions 120a and 120b may be positioned along the guidewire 100 where the majority of stresses are expected to occur during use. Typically, these are near the distal portion 112, which may directly contact tissue. The flattened portions 120a and 120b may be arranged such that there is an unflattened portion 122 (e.g., a portion of the mandrel 102 having a circular cross section) within relatively close proximity of one another. In certain embodiments, the flattened portions 120a and 120b may be arranged such that there is an unflattened portion 122 separating the flattened portions 120a and 120b. In other words, the flattened portions 120a and 120b may be arranged alternately with the unflattened portions 122 along the length of the guidewire 100. This configuration allows the guidewire 100 to distribute bending over multiple points. In other words, when the guidewire 100 contacts tissue, the guidewire 100 bends at multiple flattened portions 120a and 120b (as shown in FIG. 4 ). Although a guidewire 100 having two flattened portions has been described, it will be understood that any number of flattened portions may be arranged at various locations along the guidewire 100. The flattened portions may be positioned so as to be interleaved with the non-flattened portions 122 .

[0014] In alternative embodiments, non-flattened portion 122 may undergo some flattening, albeit to a lesser extent than flattened portions 120a and 120b, in which case flattened portions 120a and 120b will still undergo bending, but the less flattened portion will be stiffer than flattened portions 120a and 120b.

[0015] The distribution of bends along the guidewire 100 reduces the likelihood of metal fracture due to the Bauschinger effect. When a metal is work hardened in the direction of bending, it strengthens in that direction and weakens (weakens) in the opposite direction. Continued strain reversals due to bending at the same point on the guidewire 100 will eventually lead to failure of the material. In some cases, the device can withstand multiple strain reversals (repeated bending back and forth at a single point) before breaking, while in other cases the device can only withstand one strain reversal. The distribution of bends over multiple points reduces the likelihood of buckling and plastic deformation. Without plastic deformation, the Bauschinger effect cannot occur. Additionally, configuring guidewire 100 to alternate between flattened portions 120a and 120b and non-flattened portions 122 allows guidewire 100 to kink more easily by facilitating flexural-torsional buckling of the non-flattened portions as guidewire 100 attempts to reach a lower stress state, thus reducing the likelihood of a kink reoccurring at the same location on guidewire 100.

[0016] To allow for a smooth transition from the unflattened height to the flattened height, the flattened portion in some embodiments is at least 0.3 mm in length, or in other embodiments is at least 1.0 mm in length. Ideally, the flattened height of the mandrel 102 may be flattened to a height such that the guidewire 100 selectively bends at the flattened portion. In some embodiments, the first (proximal) flattened portion 120a may have a length between 1.5 mm (0.059 inches) and 2.0 mm (0.079 inches). The second (distal) flattened portion 120b may have a length between 20.0 mm (0.797 inches) and 22.0 mm (0.866 inches) and a height between 0.089 mm (0.0035 inches) and 0.114 mm (0.0045 inches). In yet another embodiment, a circular or non-flattened portion 122 may be disposed between the flattened portions 120a and 120b. The non-flattened portion 122, in embodiments, is at least 0.3 mm long, or in other embodiments, at least 1.0 mm long, to ensure that each flattened portion 120a and 120b can flex independently of one another, thereby preventing pinching in one single region. The non-flattened portion 122, in some embodiments, has a greater stiffness in at least one reference plane than each flattened portion 120a and 120b, thereby helping to ensure that bending occurs selectively in the flattened portions. Additionally, the outer diameter of the mandrel 102 to be flattened can be 0.006 inches or greater to prevent the need for additional reinforcing components (e.g., coils).

[0017] In another embodiment, the mandrel 102 may be constructed of Nitinol. Nitinol has superelastic properties that may allow the guidewire 100 to bend resistant and may eliminate the need for additional reinforcing components (e.g., inner and / or outer coils over one or more flattened regions). In an alternative embodiment, the core mandrel 102 may be constructed of stainless steel. However, stainless steel may be more prone to bending and may require reinforcing components, such as inner or outer coils over the flattened portions.

[0018] In some embodiments, the guidewire 100 may include visualization elements to allow the device to be visible under various visualization systems (e.g., fluoroscopy and / or ultrasound). In one embodiment, the guidewire 100 may include a radiopaque coil 110 (as shown in FIGS. 2 and 3). The radiopaque coil 110 may comprise a round wire tightly wound in a coil around the diameter of the mandrel 102. The radiopaque coil 110 may be disposed proximal to the flattened portions 120a and 120b. In some embodiments, the portion of the mandrel 102 that includes the radiopaque coil 110 may be ground so that the radiopaque coil 110 does not significantly increase the outer diameter of the device when placed over the mandrel 102. The radiopaque coil 110 may be constructed of any material that may be visible under fluoroscopy, such as platinum-iridium, tungsten, gold, or other materials that attenuate x-rays. The radiopaque coil 110 may be held in place distally by a coil stopper 111. In some embodiments, the flattened region 120a may function as the stopper 111, and the radiopaque coil 110 may be placed proximal to the flattened region 120a. In this embodiment, the flattened region 120a may be flattened to a particular width, for example, 0.017 inches to 0.024 inches, to hold the coil 110 in place (as seen in FIG. 5). In an alternative embodiment, the coil 110 may be placed between two of the flattened portions 120a and 120b, each of which functions as a stopper 111. Alternatively, a radiopaque marker, such as a band or ring of high density metal housed on the guidewire 100 via the stopper 111, may be used. Additionally, instead of radiopaque coil 110, a radiopaque coating may be used that is sprayed or deposited directly onto guidewire 100 and adheres to the surface of guidewire 100 without the use of any stoppers 111.

[0019] In a particular example, referring to FIG. 6, a guidewire 100 is disclosed having a distal tip 118 configured to pierce a target tissue. The guidewire 100 includes a mandrel 102 constructed from superelastic Nitinol having a circular or round cross-section. The length of the guidewire 100 may be between 70.8 inches and 90.5 inches, and the outer maximum diameter may range between 0.031 inches and 0.0315 inches. The beginning of the proximal tapered region 104 may be located 3.01 inches and 3.11 inches from the distal tip 118. The proximal tapered region 104 may range in length from 0.620 inches to 0.880 inches and tapers from a maximum outer diameter (0.031 inches to 0.0315 inches) to an outer diameter of 0.0157 inches to 0.0163 inches. The beginning of the intermediate tapered region 106 may be located 1.72 inches to 1.75 inches from the distal tip 118. The intermediate tapered section 106 may range in length from 0.09 inches to 0.11 inches and may have a reduced outer diameter ranging from 0.0117 inches to 0.0123 inches. The beginning of the distal tapered region 108 may be located 0.81 inches to 0.84 inches from the distal tip 118. The length of the distal tapered region 108 may range from 0.04 inches to 2.04 inches. The outer diameter tapers down until it reaches a range of 0.0077 inches to 0.0083 inches. Between each of the tapered regions 104, 106, and 108 is a transition region 105a and 105c.

[0020] In this example, guidewire 100 further includes two flattened portions 120a and 120b. First proximal flattened portion 120a may extend over a length of 0.059 inches to 0.079 inches and a width of 0.017 inches to 0.024 inches. The location of first proximal flattened portion 120a is at second transition region 105b between intermediate tapered region 106 and distal tapered region 108. Second distal flattened portion extends to distal tip 118 and may have a range of 0.797 inches to 0.866 inches and a height of 0.0035 inches to 0.0045 inches. Unflattened rounded portion 122 of guidewire 100 is located between proximal flattened portion 120a and distal flattened portion 120b. The length of unflattened rounded portion 122 can be between 1 mm and 3.0 mm. Distal tip 118 of guidewire 100 includes a sharpened tip having a radius of 0.001 inch (0.0254 mm) or less for mechanically piercing the target tissue.

[0021] Guidewire 100 further includes a J-shaped curved distal region 114. Curved distal region 114 extends the entire length of distal tapered region 108. The curve may have a diameter ranging from 0.27 inches to 0.35 inches. Distal to the curve, straight region 116 has a length ranging from 0.177 inches to 0.255 inches and terminates in a distal tip 118.

[0022] A radiopaque coil 110 is disposed on the guidewire 100 to allow a user to visualize the device under fluoroscopy and / or ultrasound. The radiopaque coil 110 is constructed of platinum-iridium and is disposed proximal to the first proximal flattened portion 120a and may have a length of 0.797 inches to 0.866 inches. In this example, the radiopaque coil 110 may have an inner diameter of 0.0125 inches to 0.0135 inches and an outer diameter of 0.0165 inches to 0.0175 inches.

[0023] Although multiple flattened portions 120a and 120b have been described, the flattened portions 120a and 120b can be portions with reduced stiffness and thereby be more flexible portions and can include various modifications to achieve the reduced stiffness portions.

[0024] In one alternative embodiment, the sections with reduced stiffness may be comprised of sections with reduced outer diameters, which have a reduced diameter compared to immediately adjacent regions, resulting in bending in these regions.

[0025] In yet another embodiment, portions of reduced stiffness may be achieved by introducing surface irregularities into the mandrel 102. As an example, the mandrel 102 may include portions having notches or slits that reduce the stiffness of those portions compared to adjacent portions that do not include any surface irregularities, resulting in bending of those portions.

[0026] An alternative embodiment is shown in Figures 7a-7b. In this embodiment, the mandrel 102 may be discontinuous or intermittent along its lengths 130a and 130b. To hold the discontinuous mandrel 102 together, an outer coil 132 may be wrapped around the mandrel 106 to form a unitary device. In some embodiments, the outer coil 132 may be constructed of a radiopaque material (such as platinum-iridium) to allow visualization under fluoroscopy. As shown in Figure 7b, the interruptions or discontinuities 130a and 130b bend when a force is applied to the guidewire 100.

[0027] Another alternative embodiment may include a mandrel 102 having multiple coiled portions 140a and 140b, as shown in Figures 8a-8b. The coiled portions 140a and 140b of the mandrel 102 function as flexible spring portions. The coiled portions 140a and 140b may be separated by straight portions 142. As shown in Figure 7b, the coiled portions 140a and 140b flex and bend when a force is applied to the guidewire 100.

[0028] In another alternative embodiment, guidewire 100 may include a mandrel 102 constructed from a variety of materials. For example, as shown in FIGS. 9a-9b, mandrel 102 may be formed using portions 150a and 150b of a material having a lower stiffness separated by a material 152 having a higher stiffness. In some embodiments, the higher stiffness material 152 may be a different material than mandrel 102. In alternative embodiments, the higher stiffness material 152 may be the same material as mandrel 102. The higher stiffness material and the lower stiffness material may be secured together (e.g., welded) to form a single device. As with the previous embodiment, portions 150a and 150b of guidewire 100 made of a lower stiffness material are selectively bent (as seen in FIG. 9b).

[0029] It is understood that these means of introducing reduced stiffness into the mandrel 102 of the guidewire 100 may be used independently or in combination with one another. In addition, one skilled in the art will appreciate that each of the multiple reduced stiffness portions may be different from one another. For example, a first reduced stiffness portion may be less than a second reduced stiffness portion, and both the first and second reduced stiffness portions may be less stiff than the portions adjacent to them.

[0030] Various exemplary embodiments are listed below. 1) A guidewire, The elongated member includes: A proximal portion; a distal portion, the distal portion comprising: a distal curved portion terminating in a distal tip; a tapered region that reduces the cross-section of the elongate member from a larger cross-section to a smaller cross-section; a plurality of flattened regions disposed at discrete locations along the elongate member; each of the plurality of planarized regions is separated from one another by a non-planarized region; When a force is applied to the guidewire, the guidewire undergoes bending at the multiple flattened regions.

[0031] 2) The guidewire of Example 1, wherein the elongate member is constructed from Nitinol. 3) The guidewire of any one of Examples 1 or 2, wherein the elongated member has a circular cross-section.

[0032] 4) The guidewire of any one of Examples 1-3, further comprising a radiopaque coil disposed along a distal portion. 5) The guidewire of Example 4, wherein the radiopaque coil is constructed from platinum-iridium.

[0033] 6) The guidewire of any one of Examples 4 or 5, wherein the radiopaque coil is held in place by a coil stopper. 7) The guidewire of any one of Examples 1 to 6, wherein the tapered region includes multiple tapered portions, the multiple tapered portions being separated by intermediate portions of constant diameter.

[0034] 8) The guidewire of any one of Examples 1 to 7, wherein the plurality of flattened regions includes a proximal flattened region and a distal flattened region. 9) The guidewire of Example 8, wherein the distal flattened region extends from the sharp distal tip and terminates proximal to the curved distal portion.

[0035] 10) The guidewire of any one of Examples 1 to 9, wherein the curved distal portion is J-shaped. 11) The guidewire of any one of Examples 1 to 9, wherein the curved distal portion is in the form of a pigtail.

[0036] 12) The guidewire of any one of Examples 1-11, wherein the distal tip comprises a sharpened tip configured to pierce the target tissue. 13) A guidewire described in any one of Examples 1 to 11, wherein the distal tip includes an electrode configured to deliver energy to the target tissue.

[0037] 14) A guidewire, The device further comprises an elongate member having a first stiffness, the elongate member comprising: A proximal portion; a distal portion terminating in a distal tip; a plurality of regions of a second stiffness disposed at discrete locations along the elongate member and separated by portions of the first stiffness; The second stiffness is less than the first stiffness; When a force is applied to the guidewire, the guidewire undergoes bending at multiple regions of second stiffness to prevent the guidewire from kinking.

[0038] 15) The guidewire of Example 14, wherein the distal portion comprises a distal curved portion terminating in a distal tip. 16) The guidewire of any one of Examples 14 or 15, wherein the distal curved portion is J-shaped.

[0039] 17) The guidewire of any one of Examples 14 or 15, wherein the distal curved portion is in the form of a pigtail. 18) The guidewire of any one of Examples 14 to 17, wherein the distal tip is a sharp tip configured to pierce the target tissue.

[0040] 19) The guidewire of any one of Examples 14-18, wherein the distal tip is an electrode configured to deliver energy to the target tissue. 20) The guidewire according to any one of Examples 14 to 19, further comprising a radiopaque coil.

[0041] 21) The guidewire of example 20, wherein the radiopaque coil is disposed along the distal portion. 22) The guidewire of any one of Examples 19 or 21, wherein the radiopaque coil is made of platinum-iridium.

[0042] 23) The guidewire of any one of Examples 19 to 22, wherein the radiopaque coil is held in place by a stopper. 24) The guidewire according to any one of Examples 14 to 23, wherein the elongated member is made of Nitinol.

[0043] 25) The guidewire of any one of Examples 14-24, wherein the distal portion includes a tapered region, the tapered region tapering from a larger cross section to a smaller cross section. 26) The guidewire of Example 24, wherein the tapered region includes multiple tapered portions, each of the multiple tapered portions being separated from one another by an intermediate portion having a constant cross-section.

[0044] 27) The guidewire of Example 26, wherein the multiple tapered portions include a proximal tapered portion, an intermediate tapered portion, and a distal tapered portion. 28) The guidewire according to any one of Examples 1 to 27, wherein each of the multiple regions of the second rigidity has a rigidity different from each other.

[0045] 29) The guidewire of any one of Examples 1-28, wherein the multiple regions of second stiffness include multiple flattened portions and the portion of first stiffness includes a non-flattened portion. 30) The guidewire of Example 29, wherein the plurality of flattened portions includes a proximal flattened portion and a distal flattened portion.

[0046] 31) The guidewire of Example 30, wherein the distal flattened portion extends from the distal tip and terminates proximal to the curved distal region. 32) The guidewire of any one of Examples 1-28, wherein the portion of the first stiffness comprises a first material and the multiple regions of the second stiffness include multiple regions made of a second material.

[0047] 33) The guidewire of Example 32, wherein the first material is the same material as the elongate member. 34) The guidewire of any one of Examples 1 to 28, wherein the multiple regions of second stiffness include multiple coiled regions, and the portion of the first stiffness includes a straight portion.

[0048] 35) The guidewire according to any one of Examples 1 to 28, wherein the multiple regions of the second rigidity include multiple regions having surface irregularities. 36) The guidewire of example 35, wherein the surface irregularities include a series of notches.

[0049] 37) The guidewire of any one of Examples 1 to 28, wherein the plurality of regions of second stiffness include a plurality of regions selected from the group consisting of flattened portions, or low stiffness material, or coiled portions, or combinations thereof.

[0050] 38) The guidewire according to any one of Examples 1 to 37, wherein the elongated member has a circular cross section. 39) A guidewire, The elongated member includes: A proximal portion; a distal portion, the distal portion comprising: a distal curved portion terminating in a distal tip; A plurality of interruptions; an outer coil wrapped around the elongate member such that the elongate member forms a unitary structure; When a force is applied to the guidewire, the guidewire bends at the multiple interrupted portions, preventing the guidewire from bending.

[0051] The embodiment or embodiments of the invention described above are intended to be exemplary only, and the scope of the invention is accordingly intended to be limited only by the appended claims. It will be appreciated that certain features of the invention which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0052] Although the present invention has been described in relation to specific embodiments thereof, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of a reference in this application should not be construed as an admission that such reference is available as prior art to the present invention.

Claims

1. A guidewire comprising: An elongate member having a first stiffness, the elongate member comprising: A proximal portion; a distal portion terminating in a distal tip; a plurality of regions of a second stiffness disposed at discrete locations along the elongate member and separated by portions of the first stiffness; the second stiffness is less than the first stiffness; When a force is applied to the guidewire, the guidewire bends at the multiple regions of the second stiffness to prevent the guidewire from bending.

2. The guidewire of claim 1 , wherein the distal portion includes a distal curved portion that terminates at the distal tip.

3. The guidewire of claim 1 or 2, wherein the distal curved portion is J-shaped.

4. The guidewire of claim 1 or 2, wherein the distal curved portion is in the form of a pigtail.

5. The guidewire of claim 1 , wherein the distal tip is a sharpened tip configured to pierce target tissue.

6. The guidewire of claim 1 , wherein the distal tip is an electrode configured to deliver energy to a target tissue.

7. The guidewire of claim 1 , further comprising a radiopaque coil.

8. The guidewire of claim 7 , wherein the radiopaque coil is disposed along the distal portion.

9. The guidewire of claim 6 or 8, wherein the radiopaque coil is constructed from platinum-iridium.

10. 10. The guidewire of claim 6, wherein the radiopaque coil is held in place by a stopper.

11. The guidewire of claim 1 , wherein the elongate member is constructed from Nitinol.

12. 12. The guidewire of claim 1, wherein the distal portion includes a tapered region, the tapered region tapering from a larger cross section to a smaller cross section.

13. The guidewire of claim 12 , wherein the tapered region includes a plurality of tapered portions, each of the plurality of tapered portions being separated from one another by an intermediate portion having a constant cross-section.

14. The guidewire of claim 13 , wherein the multiple tapered portions include a proximal tapered portion, an intermediate tapered portion, and a distal tapered portion.

15. The guidewire of claim 1 , wherein each of the plurality of regions of second stiffness have a different stiffness than each other.

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