Vascular Occlusion Devices

Abstract

The vaso-occlusive device includes a vaso-occlusive structure configured for implantation within an aneurysm sac, the vaso-occlusive structure being in a delivery configuration when constrained within a delivery catheter and in a deployed configuration when released from the delivery catheter into the aneurysm sac, at least a portion of the vaso-occlusive structure being comprised of an AuPtW (gold-platinum-tungsten) alloy, the AuPtW alloy including platinum in the range of 25% to 40% by weight and tungsten in the range of 0.01% to 10% by weight.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to medical devices and intravascular medical procedures, and more particularly to devices and methods for occluding vascular defects such as aneurysms. [Background technology]

[0002] Vascular occlusion devices or implants are used for a variety of reasons, including the treatment of endovascular aneurysms. An aneurysm is a dilation of a vessel, such as a blood vessel, that can rupture, clot, or dissect, posing a risk to a patient's health. For example, if an aneurysm in a patient's brain ruptures, it can cause a stroke, leading to brain damage and death. Cerebral aneurysms may be detected in a patient after, for example, a stroke or hemorrhage, and treated by applying a vaso-occlusion device.

[0003] A commonly used vaso-occlusive device comprises a soft, helically wound coil formed by wrapping a platinum (or platinum alloy) wire strand around a "primary" mandrel.

[0004] This coil is then wound around a larger "secondary" mandrel and heat treated to impart a secondary shape. For example, U.S. Patent No. 4,994,069 issued to Ritchart et al. (which is incorporated herein by reference in its entirety as if fully set forth) describes a vaso-occlusive device that assumes a straight, helical primary shape when stretched for placement through the lumen of a delivery catheter and a folded, complex secondary shape when released from the delivery catheter and placed in the vasculature. Complex three-dimensional secondary shapes can be imparted to the vaso-occlusive device to better frame and fill the aneurysm, and the stiffness / flexibility of the vaso-occlusive device can be altered.

[0005] To deliver a vaso-occlusive device to a desired location within the vasculature, such as an aneurysmal sac, it is common to first position a small-profile delivery catheter or “microcatheter” at the desired location using a guidewire. Typically, the distal end of the microcatheter is provided with a pre-formed bend selected by the attending physician or manufacturer, such as a 45-degree, 26-degree, “J,” “S,” or other bend, depending on the patient's specific anatomy, so that it remains in a specific position to release one or more vaso-occlusive devices into the aneurysmal sac when the guidewire is withdrawn. A delivery or “pusher” assembly or “wire” is then threaded through the microcatheter until the vaso-occlusive device, coupled to the distal end of the delivery assembly, extends from the distal end opening of the microcatheter into the aneurysmal sac. Once inside the aneurysmal sac, a portion of the vaso-occlusive device can be deformed or bent to allow for more efficient and complete filling.

[0006] The vaso-occlusive device is then released or "detached" from the distal end of the delivery assembly, and the delivery assembly is pulled back through the microcatheter. Depending on the patient's specific needs, one or more additional vaso-occlusive devices can be pushed through the microcatheter and released into the same aneurysm sac.

[0007] Fluoroscopy is used to visualize the vascular occlusion device during delivery into the aneurysm, while magnetic resonance imaging (MRI) can typically be used to visualize the treatment site post-procedure (e.g., several weeks after initial aneurysm treatment) to confirm that the aneurysm sac has been properly occluded. To this end, vascular occlusion devices can be constructed to minimize visualization-impairing artifacts (i.e., MRI-compatible) while allowing for their radiopacity during aneurysm treatment. Furthermore, to prevent rupture of the delicate tissues of the aneurysm, it is paramount that such vascular occlusion devices be "soft" (i.e., laterally flexible or malleable) and therefore atraumatic.

[0008] It is also important that such vaso-occlusive devices remain within the aneurysm for an extended period of time. However, aneurysms with large openings, commonly known as "wide-neck aneurysms," present challenges in deploying and retaining vaso-occlusive devices within the aneurysm sac. Small, relatively thin vaso-occlusive coils, in particular, lack substantial secondary structural strength to maintain their position within the aneurysm sac, no matter how skillfully they are deployed. Therefore, to securely retain the vaso-occlusive coil within the aneurysm sac, a stent or balloon may be placed in the blood vessel adjacent to the aneurysm neck, complicating the procedure. To address this issue, vaso-occlusive devices composed at least in part of a braided (or woven) structure have been developed. Such braided vaso-occlusive devices provide a wide coverage and effective backbone across the aneurysm neck, allowing for effective retention within a wide-neck aneurysm without the deployment of an ancillary aneurysm retention device, such as a balloon or stent.

[0009] However, regardless of whether a coiled or braided vaso-occlusive device is used, the vaso-occlusive device delivery system requires that the vaso-occlusive device be relatively short and have limited expandability, otherwise pushing it into and withdrawing it from the microcatheter would be difficult (if not impossible). Unfortunately, small (short) vaso-occlusive devices are less advantageous because delivering such small vaso-occlusive devices into the aneurysm sac requires a longer and more complicated procedure. For example, a 7 mm diameter neuroaneurysm sac is typically filled with 5 to 7 individual spring-type coils, resulting in a longer and more complicated procedure than if fewer devices were used.

[0010] Theoretically, the length of the vaso-occlusive device can be increased to reduce the number of vaso-occlusive devices required to treat an aneurysm. However, increasing the length of the vaso-occlusive device inevitably increases friction between the vaso-occlusive device and the lumen of the delivery catheter. Therefore, to ensure reliable delivery of the vaso-occlusive device into the aneurysm, the column strength of the vaso-occlusive device may be increased (e.g., by selecting a material with a high Young's modulus or increasing the diameter of the wire from which the vaso-occlusive device is formed) and / or the diameter of the delivery catheter may be increased. However, as mentioned above, it is advantageous to both minimize the diameter of the delivery catheter so that the aneurysm can be accessed through a very small vasculature and to ensure that the vaso-occlusive device is soft enough to avoid damaging the delicate aneurysm tissue.

[0011] There are very few materials available that have suitable column strength for relatively long vascular occlusion devices to be delivered through relatively small diameter delivery catheters while meeting other competing design parameters, including softness, radiopacity, and MRI compatibility.

[0012] For example, known materials with relatively high Young's modulus and relatively high radiopacity, such as platinum-tungsten (PtW) alloys from which vaso-occlusive coils are typically fabricated, can be used to provide suitable column strength for relatively long vaso-occlusive devices. However, the diameter of the wire from which such vaso-occlusive devices are fabricated may be reduced to achieve a certain softness while still allowing the vaso-occlusive device to fit within a small-diameter delivery catheter. This results in a decrease in the radiopacity of the vaso-occlusive device and a decrease in column strength, requiring a shorter vaso-occlusive device and / or a larger-diameter delivery catheter.

[0013] As another example, known materials with relatively low Young's modulus and low radiopacity, such as nitinol, can be used to provide suitable flexibility for vaso-occlusive devices. However, such vaso-occlusive devices lose adequate radiopacity and column strength as the length of the vaso-occlusive device increases. Furthermore, the heating process used to set nitinol into a predetermined shape results in surface oxides that can crack and release toxic nickel. Therefore, such oxides may be removed from vaso-occlusive devices using costly and time-consuming processes.

[0014] As yet another example, known materials with relatively intermediate Young's modulus and low radiopacity, such as titanium, can be used to provide adequate column strength for relatively long, soft vaso-occlusive devices if an optimal diameter is selected for the wire from which such vaso-occlusive devices are fabricated, however, such vaso-occlusive devices would not exhibit sufficient radiopacity.

[0015] Thus, there is a continuing need to provide vaso-occlusive devices that meet one or more of the above-mentioned design parameters. Summary of the Invention

[0016] SUMMARY OF THE INVENTION The embodiments described herein are directed to implantable medical devices, such as embolic devices and blood flow filters, that are at least partially made (ie, constructed) from a gold-platinum-tungsten alloy.

[0017] In various embodiments, the implantable device is made from one or more elongated members made of gold-platinum-tungsten alloy, such as in the form of cut tubing, coiled wire, or multiple wires woven into a braid. Without limitation, the elongated member can include a composite or non-composite wire having at least one layer, at least a core, or the entire cross section made of gold-platinum-tungsten alloy.

[0018] The vaso-occlusive device includes a vaso-occlusive structure configured to be implanted within an aneurysm sac, the vaso-occlusive structure being in a delivery configuration when constrained within a delivery catheter and in a deployed configuration when released from the delivery catheter into the aneurysm sac, at least a portion of the vaso-occlusive structure being composed of an AuPtW (gold-platinum-tungsten) alloy, the AuPtW alloy including platinum in the range of 25% to 40% by weight and tungsten in the range of 0.01% to 10% by weight.

[0019] Optionally, the AuPtW alloy has a Young's modulus of less than 25 megapounds per square inch (Mpsi).

[0020] Optionally, the vaso-occlusive structure comprises a mesh made of an AuPtW alloy.

[0021] Optionally, the mesh is braided.

[0022] Optionally, the entire vaso-occlusive structure comprises a mesh.

[0023] Optionally, the vaso-occlusive structure further comprises two helically wound coils disposed on opposite ends of the mesh.

[0024] Optionally, each of the two helically wound coils is constructed from an AuPtW alloy.

[0025] Optionally, the mesh comprises at least one wire, each wire having a minimum cross-sectional dimension in the range of 0.0005 inches to 0.004 inches.

[0026] Optionally, the mesh comprises at least one twisted strand.

[0027] Optionally, the mesh has a wire count in the range of 8 to 96 wires.

[0028] Optionally, the mesh has a wire count in the range of 16 to 32 wires.

[0029] Optionally, the mesh has an unconstrained braid angle in the range of 20 degrees to 60 degrees.

[0030] Optionally, the mesh has an extended geometric shape with a circular cross section.

[0031] Optionally, the mesh has an extended geometric shape with a rectangular cross section.

[0032] Optionally, the rectangular cross-section has a width in the range of 0.5 mm to 5.0 mm.

[0033] Optionally, the mesh has a bending stiffness of less than 150 mN / mm.

[0034] Optionally, the vaso-occlusive structure includes a coil made of an AuPtW alloy.

[0035] Optionally, the coil is configured to assume a three-dimensional shape having multiple loops when deployed from the delivery catheter.

[0036] The vaso-occlusive assembly includes a vaso-occlusive device and a pusher member to which the vaso-occlusive device is removably coupled.

[0037] A vascular occlusion treatment system includes a vaso-occlusion assembly as claimed and a delivery catheter in which the vaso-occlusion assembly is disposed.

[0038] The vaso-occlusive device includes a vaso-occlusive structure configured for implantation within the aneurysm sac, the vaso-occlusive structure being in a delivery configuration when constrained within a delivery catheter and in a deployed configuration when released from the delivery catheter into the aneurysm sac, at least a portion of the vaso-occlusive structure being composed of an AuPtW (gold-platinum-tungsten) alloy.

[0039] Other and further aspects and features will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a side view of a vascular occlusion treatment system, particularly showing a vascular occlusion within a delivery catheter in a delivery configuration. [Figure 2] FIG. 2 is a side view of the vascular occlusion treatment system of FIG. 1, particularly showing the vascular occlusion device deployed from the delivery catheter in an expanded configuration. [Figure 3] 3 is a plan view of the vaso-occlusive structure of the vaso-occlusive treatment system of FIG. 1 deployed within an aneurysm sac. [Figure 4] 4 is a plan view of a mesh portion of the vascular occlusion structure of the vascular occlusion treatment system of FIG. 1. FIG. [Figure 5] Figure 5A is a cross-sectional view of the wire used in the mesh portion of Figure 4. Figure 5B is a cross-sectional view of the wire used in the mesh portion of Figure 4. Figure 5C is a cross-sectional view of the wire used in the mesh portion of Figure 4. [Figure 6] Figure 6A is a cross-sectional view of a mesh portion of the vascular occlusion treatment system of Figure 1. Figure 6B is a cross-sectional view of the mesh portion of the vascular occlusion treatment system of Figure 1. [Figure 7] FIG. 7 shows the AuW phase diagram. [Figure 8] 8A and 8B show another embodiment of a vaso-occlusive device. [Figure 9] FIG. 9 is a side view of a vascular occlusion treatment system, particularly showing a vascular occlusion within a delivery catheter in a delivery configuration. [Figure 10] FIG. 10 is a side view of the vascular occlusion treatment system of FIG. 9, particularly showing the vascular occlusion device deployed from the delivery catheter in an expanded configuration. DETAILED DESCRIPTION OF THE INVENTION

[0041] For the following defined terms, these definitions shall be applied unless a different definition is given in the claims or elsewhere in this specification.

[0042] All numerical values ​​herein are deemed to be modified by the term "about," whether expressly stated or not. The term "about" generally refers to a range of numerical values ​​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" can include numerical values ​​that are rounded to the nearest significant figure.

[0043] The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0044] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used herein and in the appended claims, the term "or" is typically used in its sense including "and / or" unless the content clearly dictates otherwise.

[0045] Various features will now be described with reference to the drawings. The drawings are not necessarily drawn to scale, the relative scale of selected elements may be exaggerated for clarity, and elements of similar structure or function are designated by like reference numerals throughout the drawings. It should also be understood that the drawings are intended to facilitate the description of features and are not intended as an exhaustive description of the claimed invention or as limiting its scope as defined by the appended claims and their equivalents.

[0046] Furthermore, each illustrated embodiment of the disclosed invention need not have all of the illustrated features, and a feature, aspect, or advantage described in connection with a particular embodiment is not necessarily limited to that embodiment and may also be implemented in other embodiments, even if not so illustrated.

[0047] 1 and 2, one embodiment of a vascular occlusion treatment system 10 constructed in accordance with the present invention will be described. The vascular occlusion treatment system 10 includes a delivery catheter 12 and a vascular occlusion assembly 14 slidably disposed within the delivery catheter 12. The vascular occlusion assembly 14 includes a vascular occlusion structure 16 and a pusher member 18 to which the vascular occlusion structure (or vascular occlusion device) 16 is removably coupled at a joint 20.

[0048] The delivery catheter 12 has a tubular configuration and may take the form of, for example, a microcatheter. The delivery catheter 12 includes an elongate sheath body 22 having a proximal portion 24 and a distal portion 26, and a lumen 28 (shown in dashed lines) extending through the sheath body 22 between the proximal portion 24 and the distal portion 26. The proximal portion 24 of the sheath body 22 remains outside the patient and is accessible to an operator during use of the vascular occlusion treatment system 10, while the distal portion 26 of the sheath body 22 is sized and dimensioned to reach remote locations in the vasculature and is configured to deliver the vascular occlusion structure 16 to an aneurysm. The delivery catheter 12 may have at least one port 30 in fluid communication with the lumen 28 of the delivery catheter 12, which is used to introduce fluid into the sheath body 22. The vascular occlusion assembly 14 is disposed within the lumen 28 of the delivery catheter 12, as best seen in FIG. 1 .

[0049] The delivery catheter 12 may include one or more regions along its length, or multiple regions, having different configurations and / or properties. For example, the distal portion 26 of the sheath body 22 may have an outer diameter that is smaller than the outer diameter of the proximal portion 24 of the sheath body 22 to reduce the profile of the distal portion 26 and facilitate navigation through tortuous vasculature. Additionally, the distal portion 26 may be more flexible than the proximal portion 24. Generally, the proximal portion 24 is formed from a stiffer material than the distal portion 26 of the sheath body 22 such that the proximal portion 24 has adequate pushability for advancement through a patient's vasculature (e.g., without the proximal portion 24 buckling or breaking), while the distal portion 26 may be formed from a more flexible material so that the distal portion 26 remains flexible and can more easily be advanced over a guidewire to access remote locations in tortuous regions of the vasculature. The sheath body 22 may be constructed from a suitable polymeric material, such as polyethylene or stainless steel, a metal and / or alloy, or other suitable biocompatible material, or a combination thereof. In some embodiments, the proximal portion 24 may include a reinforcing layer, such as a braided or coiled layer, to enhance the pushability of the sheath body 22. The sheath body 22 may include a transition region between the proximal portion 24 and the distal portion 26. In some cases, the distal portion 26 may also include a reinforcing layer.

[0050] Generally, the vascular occlusion structure 16 can be inserted into a patient (e.g., minimally invasively) by inserting the vascular occlusion treatment system 10 into the patient's vasculature and reaching the aneurysm site. Therefore, the delivery catheter 12 is made as small as possible and has a very small inner diameter (i.e., lumen 28) (e.g., 0.015 inches to 0.025 inches, preferably 0.015 inches to 0.018 inches). The vascular occlusion treatment system 10 can be used in an "over-the-wire" configuration, in which the delivery catheter 12 is introduced into the patient over a previously introduced guidewire, and the delivery catheter 12 extends the entire length of the guidewire (not shown). Alternatively, the vascular occlusion treatment system 10 can be used in a "rapid-exchange" configuration, in which the guidewire extends from a guidewire port (not shown) through the distal portion of the vascular occlusion treatment system 10. In other alternative embodiments, the distal portion of the sheath or access catheter may be left at the target site, the guidewire may be withdrawn, and the vascular occlusion treatment system 10 may be introduced into the patient, and the vascular occlusion treatment system 10 may be navigated through the patient's vasculature within the sheath or access catheter.

[0051] It should be noted that the delivery catheter 12 is not limited to having the example dimensions described above, and in other embodiments, the delivery catheter 12 can have other dimensions. For example, in other embodiments, the lumen of the delivery catheter 12 can have an inner diameter of less than 0.020 inches, less than 0.018 inches, less than 0.016 inches, or less than 0.014 inches (e.g., 0.013 inches or less). In other embodiments, the lumen of the delivery catheter 12 can have an inner diameter greater than 0.020 inches, such as 0.04 inches, 0.06 inches, 0.08 inches, 0.1 inches, or 0.2 inches.

[0052] As shown in FIGS. 1 and 2 , when the vascular occlusion structure 16 is contained within the delivery catheter 12, the vascular occlusion structure 16 has a first cross-sectional dimension, and when the vascular occlusion structure 16 is delivered outside the delivery catheter 12, the vascular occlusion structure 16 has a second cross-sectional dimension that is larger than the first cross-sectional dimension. In particular, when the vascular occlusion structure 16 is inside the delivery catheter 12, the vascular occlusion structure 16 elastically collapses radially to form the first cross-sectional dimension. When the vascular occlusion structure 16 is outside the delivery catheter 12, the vascular occlusion structure 16 elastically returns radially outward to assume its second cross-sectional dimension. In some embodiments, in addition to expanding radially from the longitudinal axis of the vascular occlusion structure 16, the vascular occlusion structure 16 may also assume a three-dimensional configuration. By way of non-limiting example, the vascular occlusion structure 16 can assume multiple loops (e.g., open and / or closed loops), a helical configuration, a random configuration, etc. In some embodiments, when the vasoocclusive structure 16 has a three-dimensional configuration with multiple loops, the loops can lie in respective planes, and at least two of the planes can form a non-zero angle with respect to each other.

[0053] As shown in FIG. 3 , at the aneurysm site, the vaso-occlusive structure 16 can be pushed from the delivery catheter 12 in the parent vessel V via the pusher member 18, distally through the aneurysm neck N, and into the aneurysm sac A. After being pushed out of the delivery catheter 12, the vaso-occlusive structure 16 can self-expand to a preset configuration, as described below. Once inserted into the aneurysm sac A, the vaso-occlusive structure 16 can be detached from the pusher member 18. Multiple vaso-occlusive devices 16 can be delivered to fill and occlude the aneurysm sac A. Alternatively, the vaso-occlusive structure 16 can be removed or withdrawn by retracting the vaso-occlusive structure 16 proximally via the pusher member 18, and then collapsed and retracted into the delivery catheter 12.

[0054] The pusher member 18 may be a coil, wire, tendon, or the like having suitable column strength to enable the vaso-occlusive structure 16 to be pushed into the aneurysm sac. The joint 20 at which the pusher member 18 is coupled to the vaso-occlusive structure 16 may take the form of, for example, an electrolytically degradable segment for electrolytically detaching the vaso-occlusive structure 16 from the pusher member 18, although other alternative detachment mechanisms may include mechanical, thermal, and hydraulic mechanisms for detaching the vaso-occlusive structure 16 from the pusher member 18.

[0055] The pusher member 18 has a proximal portion 32 extending proximally from the proximal portion 24 of the delivery catheter 12 and a distal portion 34 to which the vaso-occlusive device 16 is attached. The pusher member 18 may be made of a guidewire, a torqueable cable tubing, or a hypotube. In either case, there are many materials available for the pusher member 18 to achieve suitable properties typically associated with medical devices. Some examples may include metals, metal alloys, polymers, metal-polymer composites, etc., or any other suitable material. For example, the pusher member 18 may include a nickel-titanium alloy, stainless steel, a composite of nickel-titanium alloy and stainless steel, etc. In some embodiments, at least a portion (e.g., a layer) or the entire pusher member 18 may be made of a nickel-titanium-platinum (NiTiPt) alloy. In some cases, the pusher member 18 may be made of the same material along its length, or in some embodiments, may include portions or sections made of different materials. In some embodiments, the materials used to construct the pusher member 18 are selected to impart varying flexibility and stiffness characteristics to different portions of the pusher member 18. For example, the proximal region and distal portion 34 of the pusher member 18 may be formed of different materials, e.g., materials having different moduli of elasticity, resulting in differences in flexibility. For example, the proximal portion 32 may be formed of stainless steel, while the distal portion 34 may be formed of a nickel-titanium alloy. However, any suitable material or combination of materials may be used for the pusher member 18.

[0056] The vaso-occlusive structure 16 is sized for implantation within the aneurysmal sac A and can take any geometric or cross-sectional shape. For example, in the illustrated embodiment, the vaso-occlusive structure 16 takes the form of an elastic tubular member having a proximal end 36 and a distal end 38. In this case, the distal end 38 of the vaso-occlusive structure 16 is typically free or released (allowing for maximum expansion), while the proximal end 36 of the vaso-occlusive structure 16 is coupled / attached to the pusher member 18. Thus, the distal end 38 of the vaso-occlusive structure 16 is free-floating. In another example, the vaso-occlusive structure 16 can take the form of a flat member that can be anchored at both the proximal and distal ends (allowing for minimal expansion). The vaso-occlusive structure 16 has a compact delivery configuration when radially constrained within the delivery catheter 12 and is biased to expand radially outward to a deployed configuration when released from the delivery catheter 12 into the aneurysmal sac. The cross-sectional dimension of the vaso-occlusive structure 16 in its expanded, deployed configuration may be, for example, more than 1.5 times larger, preferably more than 2 times larger, and most preferably more than 3 times larger than the cross-sectional dimension of the vaso-occlusive structure 16 in its compact delivery configuration. The expanded, deployed configuration of the vaso-occlusive structure 16 may be preset, may be bent, curved, or three-dimensional (e.g., ball-shaped, loop-shaped, etc.), and may include secondary or tertiary structures.

[0057] 1 and 2, the entire vaso-occlusive structure 16 includes a porous mesh 40 constructed from an AuPtW alloy, although, as described in further detail below, only a portion of the vaso-occlusive structure 16 can include the mesh 40. In the illustrated embodiment, the mesh 40 is formed by braiding or weaving together wires 42 (e.g., having a wire count of 8-96, more preferably 16-32) (FIG. 4). In alternative embodiments, the mesh 40 can be formed as a monolithic structure, for example, by etching or cutting a pattern from a tube or sheet of stent material, or by cutting or etching a sheet of material according to a designed pattern and then rolling or otherwise forming the sheet into a tubular, branched, or other shape.

[0058] The mesh 40 can have any suitable length (e.g., greater than 5 cm, 5 cm to 45 cm, 5 cm to 30 cm, etc.). The braid can be braided using a braiding machine around a mandrel (e.g., a circular, oval, flat, or other shaped mandrel depending on the final cross-sectional shape of the vaso-occlusive structure 16 to be achieved). Alternatively, the wire 42 can be braided into a flat braid, which can then be formed and heat-set around a mandrel to form a flat braid having a predetermined shape. After braiding, the mesh 40 can be heat-set (e.g., at 450°C to 650°C for 1 to 60 minutes). The heat-set braid forms the linear "primary shape" of the mesh 40. The heat-set braid can then be wrapped around a second mandrel (e.g., a three-dimensional mandrel) and heat-set a second time to impart a three-dimensional "secondary shape" or "tertiary shape."

[0059] Each wire 42 may be a monofilament strand, as shown in FIGS. 5A and 5B, or in an alternative embodiment, each wire 42 may be a multifilament strand, as shown in FIG. 5C. Each wire 42 may have any suitable cross-section with any suitable dimensions. For example, if each wire 42 has a circular cross-section (as shown in FIG. 5A), the diameter may be 0.0005 inches to 0.0040 inches, and if each wire 42 has a rectangular cross-section (as shown in FIG. 5B), the thickness may be 0.0008 inches or more and the width may be 0.005 inches or less. In another embodiment, each wire 42 may be in the form of a twisted wire (as shown in FIG. 5C) to increase the flexibility of the resulting vaso-occlusive structure 16.

[0060] While all of the wires 42 making up the mesh 40 may be the same size and composition, it should be understood that the wires 42 may have different sizes and compositions, so long as at least some of the wires 42 making up the vaso-occlusive structure 16 are composed of an AuPtW alloy. In some embodiments, the mesh 40 may be a braid, such as a ribbon braid. The braid may be made from wires of the same size or from wires of different sizes. In some embodiments, the braid may be made from wires having the same composition or from wires having different compositions. Preferably, the unconstrained braid angle 44 of the mesh 40 (i.e., the angle between two intersecting wires 42) is between 20 degrees and 130 degrees, more preferably between 20 degrees and 60 degrees (FIG. 4). Generally, the braid angle 44 may be the angle between two intersecting wires 42 viewed longitudinally. The braid angle 44 can be selected to enhance the pushability of the vaso-occlusive structure 16 within the delivery catheter 12 by preventing the mesh 40 from collapsing, which would otherwise cause the mesh 40 to bunch within the delivery catheter 12 when pushed, causing the vaso-occlusive structure 16 to become clogged within the delivery catheter 12. Ultimately, the number of wires 42 within the mesh 40, the braid angle 44, and / or the collapsed versus expanded configuration of the mesh 40 can be selected to optimally fit the inner diameter of the delivery catheter 12 being used.

[0061] In some embodiments, mesh 40 can be a braided structure having a tubular configuration. In other embodiments, mesh 40 can have a non-tubular configuration. For example, in some embodiments, mesh 40 can be a flat braid. A flat braid can be any braided structure having a cross-section with a width W and a thickness T (measured perpendicular to the width), where the ratio W / T is equal to or greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. Also, in some embodiments, mesh 40 can be a ribbon braid. In one or more embodiments described herein, the braid can have a width anywhere from 0.020 inches (0.5 mm) to 0.197 inches (5 mm), preferably anywhere from 0.030 inches (0.75 mm) to 0.079 inches (2.0 mm), and more preferably anywhere from 0.030 inches (0.75 mm) to 0.06 inches (1.5 mm). In further embodiments, the braid can have a width of 0.039 inches (1 mm) or greater. For example, in one embodiment, the braid can have a width of about 1.25 mm (e.g., 1.25 mm ± 0.1 mm). In some embodiments, the braid can have a braid stiffness of less than 150 mN / mm. Furthermore, in some embodiments, the braid can be formed from multiple braided wires 42 of the same size and / or the same composition. In other embodiments, the braid can be formed from multiple braided wires 42 of different sizes and / or different compositions.

[0062] In some embodiments, the braid can have a first width when unconstrained outside the catheter, and can elastically collapse and / or bend laterally (e.g., perpendicular to the longitudinal axis of the braid) to a second width less than the first width when the braid is inside the catheter. For example, the braid can be a flat braid that is elastically curled or rolled up to have the second width inside the catheter, and can elastically return to a relaxed configuration having the first width when deployed outside the catheter.

[0063] In one embodiment, shown in FIG. 6A, mesh 40 has an expanded geometry that is flat (e.g., ribbon) and can have a width ranging from 0.5 mm to 5.0 mm. In an alternative embodiment, shown in FIG. 6B, mesh 40 has an expanded geometry that is cylindrical (i.e., has a circular cross-section) and can have a diameter ranging from 0.5 mm to 5.0 mm. Thus, mesh 40 can be a flat braid or a rolled braid. In some embodiments, regardless of whether mesh 40 has a flat or rolled cross-section, mesh 40 has suitable column strength for advancement relative to delivery catheter 16 (e.g., does not buckle, kink, bend, etc. within the lumen of delivery catheter 16 as mesh 40 advances).

[0064] Through prototyping and testing, the exact composition of the AuPtW alloy, the size and number of wires 42, the braid angle used to construct the mesh 40 of the vaso-occlusive structure 16, and the shape and size of the expanded vaso-occlusive structure 16 can be optimized to deliver superior performance depending on the target application.

[0065] For example, in some embodiments, a relatively soft, long, yet radiopaque vaso-occlusive device can be constructed by braiding N wires (e.g., a number ranging from 8 to 96, preferably 16 to 32, e.g., 24) into a flat braid having a width of 0.5 to 5 mm (preferably 1 to 2 mm, e.g., 1.25 mm) and a length of 12 cm or more, with a braid angle (unconstrained) of 20 to 130 degrees (preferably 20 to 60 degrees), each wire being composed of AuPtW, having a Young's modulus of less than 25 MPa, and a wire diameter of 0.0005 inches to 0.004 inches (e.g., 0.001 inches). The vaso-occlusive device can be deliverable through a microcatheter (e.g., having an outer diameter of 0.026 inches and an inner diameter of 0.0165 inches). In some embodiments, the vaso-occlusive device can be delivered with a frictional force of less than 0.06 pounds. Such vaso-occlusive devices can have advantageous shape retention properties, a particular bending stiffness (e.g., less than 150 mN / mm), and can have particular radiopacity, such as for imaging at X-ray energies of 82 kilovolts peak (KVp). Also, in some embodiments, MRI images (e.g., MRI at 3T) of the novel AuPtW vaso-occlusive coils are advantageously substantially free of interface artifacts that can be present in existing vaso-occlusive coils (e.g., vaso-occlusive coils made from Pt / 8W).

[0066] Importantly, the inventors have found that a gold-platinum-tungsten (AuPtW) alloy, preferably comprising platinum in the range of 25% to 40% by weight, tungsten in the range of 0.01% to 10% by weight, and balance Au (e.g., %Au=100%-%Pt-%W), and having a Young's modulus of less than 25×10^6 pounds per square inch (25 MPa), allows the vaso-occlusive structure 16, when properly configured, to exhibit a particular softness (e.g., a bending stiffness of less than 150 mN / mm), have a particular length (e.g., greater than 5 cm), fit into a small diameter delivery catheter (e.g., an inner diameter of 0.017 inches), have a particular radiopacity, have a particular MRI compatibility, and be easily manufactured (e.g., eliminating the need for surface oxide removal). In other embodiments, in addition to the AuPtW alloy, the vaso-occlusive structure 16 can further include iridium to improve its mechanical properties.

[0067] It should be noted that the vaso-occlusive structure 16 is not limited to having the example dimensions and characteristics described herein, and that the vaso-occlusive structure 16 can have various dimensions and characteristics in various embodiments. For example, in some embodiments, the vaso-occlusive structure 16 can include a braided structure formed from braided wires 42. The braided wires 42 can have different shapes in different embodiments. For example, at least one of the braided wires 42 can have a circular cross-section, a square cross-section, an oval cross-section, or a rectangular cross-section. In some embodiments, at least one of the braided wires 42 can have a cross-sectional dimension between 0.0001 inches (0.00254 mm) and 0.004 inches (0.1016 mm). In other embodiments, the braided wire 42 can have a cross-sectional dimension that is less than 0.00085 inches (0.022 mm), preferably anywhere between 0.0001 inches (0.00254 mm) and 0.0008 inches (0.020 mm), and more preferably anywhere between 0.0003 inches (0.0076 mm) and 0.00075 inches (0.019 mm).

[0068] In some embodiments, when braided wire 42 has a circular cross-section, the cross-sectional dimensions described herein are the diameter of the circular cross-section. In such cases, the diameter can be in the range of 0.0005 inches (0.0127 mm) to 0.004 inches (0.102 mm), preferably in the range of 0.0008 inches (0.0203 mm) to 0.004 inches (0.102 mm), and more preferably in the range of 0.001 inches (0.0254 mm) to 0.002 inches (0.051 mm). In other embodiments, the diameter of the circular cross-section of braided wire 42 can be less than 0.00085 inches, preferably 0.0001 inches to 0.0008 inches, and more preferably 0.0003 inches to 0.00075 inches. In further embodiments, the braided wire 42 can have a diameter anywhere from 0.0001 inches (0.00254 mm) to 0.0015 inches (0.0381 mm), preferably anywhere from 0.0005 inches (0.0127 mm) to 0.001 inches (0.0254 mm).

[0069] Also, in some embodiments, the braided wire 42 can have an elongated cross-section (e.g., oval, rectangular, etc.) having a width W1 and a height (or thickness) H1. In some embodiments, the width W1 can be 0.005 inches or less, and the height H1 can be at least 0.0008 inches. In other embodiments, the braided wire 42 can have a width (W1) of 0.004 inches (0.102 mm) and a height (H1) of 0.002 inches (0.051 mm). In other embodiments, the braided wire 42 can have a maximum width of 0.002 inches (0.051 mm) and a minimum height of 0.0001 inches (0.00254 mm). In further embodiments, the braided wire 42 can have a cross-sectional dimension (width or thickness) of less than 0.00085 inches.

[0070] In some embodiments, the braided structure can be formed from one or more twisted strands. Additionally, in some embodiments, the braided structure can have a wire count of 8 to 96, 16 to 32, 24 to 144, or 24 to 72. Additionally, in some embodiments, the braided structure can be formed from a braid wire 42 that is a ribbon wire.

[0071] It should be noted that using AuPtW alloys to construct vascular occlusion devices is counterintuitive, since it is believed that AuPt alloys cannot be strengthened by alloying with tungsten (W). Au and W are a difficult combination to alloy for several reasons. First, tungsten has a much higher melting point (3422°C) than gold (1064°C), making it difficult to achieve a uniform solid solution and uniform chemical composition. Second, according to the AuW phase diagram (Figure 7), Au and W appear to be immiscible, in that they cannot form a single phase or a uniform solid solution at low temperatures. Additionally, because tungsten has an ultrahigh hardness and high elastic modulus, alloying with tungsten is thought to potentially result in a brittle alloy. For these reasons, AuPtW alloys, especially in wire form, are not currently available commercially or academically. For these same reasons, AuPtW alloys have not been used to construct implants such as vascular occlusion devices.

[0072] Nevertheless, the inventors discovered that combining AuPt and PtW allows for the formation of a uniform AuPtW ternary alloy, since platinum (Pt) acts as an inter-alloying element between gold (Au) and tungsten (W) to form an infinite solid solution. Furthermore, through thorough analysis and prototyping, the inventors discovered that by controlling the tungsten content to less than 10 wt%, the AuPtW alloy possesses a range of mechanical properties suitable for the fabrication of implants such as vascular occlusion devices. On the other hand, if the tungsten content in the AuPtW alloy exceeds 10 wt%, the resulting alloy is too brittle to be drawn into wire for braiding or coil production, or too hard to be used in the fabrication of implants.

[0073] In some embodiments, adding tungsten to the Au-Pt combination to form the alloy has the advantage of increasing the mechanical strength (ultimate tensile strength) to the range of 200-300 Kpsi, compared to 125-175 Kpsi for tungsten-free AuPt alloys. However, tungsten itself has a very high elastic modulus. For this reason, the tungsten content is controlled to 10% or less to achieve good mechanical strength while maintaining an elastic modulus level of less than 25 Kpsi, which is suitable for occlusion device applications.

[0074] In some embodiments, a vaso-occlusive structure 16 made from an AuPtW alloy has the same or greater softness, the same or greater radiopacity, and the same or greater braid length as a vaso-occlusive structure made from an AuPt alloy (without tungsten in the alloy).

[0075] Various techniques can be employed to fabricate AuPtW alloys in various embodiments. In one exemplary embodiment, solid PtW and AuPt alloys can be obtained, followed by melting the alloys to obtain PtW and AuPt solutions. The solutions can then be mixed to form an AuPtW solution that achieves a designed composition (e.g., 25-40 wt. % Pt and 0.01-10 wt. % W, with the remainder Au, based on the weight of the designed AuPtW composition). In some embodiments, in a fine-tuning step, additional Au solution, Pt solution, W solution, or any combination of the foregoing can be optionally added to the mixed solution to achieve the designed weight percentages of each component (Au, Pt, W).

[0076] In some embodiments, a solid form of alloy AuPt is first obtained. The AuPt alloy can be formed using a certain amount of Pt (e.g., 25-40 wt. % based on the weight of the designed AuPtW composition). The AuPt alloy can then be heated to melt the alloy and obtain an AuPt solution. Solid tungsten is then obtained and melted to form a tungsten solution. A certain amount of the molten tungsten solution (e.g., less than 10 wt. % based on the weight of the designed AuPtW composition) is then added to the AuPt solution to form an AuPtW solution. In some embodiments, in a fine-tuning step, additional Au solution, Pt solution, W solution, or any combination of the aforementioned can be optionally added to the mixed solution to achieve the designed weight percentages of each component (Au, Pt, W).

[0077] In other embodiments, a solid form of alloy PtW is first obtained. The PtW alloy can be formed using a certain amount of Pt (e.g., 25-40 wt. % based on the weight of the designed AuPtW composition) and a certain amount of W (e.g., less than 10 wt. % based on the weight of the designed AuPtW composition). The PtW alloy is then heated to melt the alloy and obtain a PtW solution. Solid Au is then obtained and melted to form an Au solution. A certain amount of the molten Au solution is then added to the PtW solution to form the AuPtW solution. In some embodiments, in a fine-tuning step, additional Au solution, Pt solution, W solution, or any combination of the aforementioned can be optionally added to the mixed solution to achieve the designed weight percentage of each component (Au, Pt, W).

[0078] Also, in some embodiments, the vaso-occlusive device can have an AuPtW alloy that is at least: 50%, 60%, 70%, 80%, 90%, 95%, 97%, 98%, 99%, 99.5%, 99.9%, etc., by weight of the vaso-occlusive device. Furthermore, it should be understood that the total percentage of gold (Au) and platinum (Pt) in the alloy can be equal to or less than 100%-Pw (where Pw indicates the percentage W content in the AuPtW alloy) as long as the percentage composition of tungsten (W) is 10% or less by weight of the AuPtW alloy.

[0079] In some embodiments, the AuPtW material may be further alloyed with one or more other materials. For example, in other embodiments, AuPtW may be alloyed with tantalum (Ta), iridium (Ir), rhenium (Re), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), or any combination thereof to achieve a particular level of mechanical properties (e.g., to enhance the mechanical properties of the material). In further embodiments, the AuPtW material may be further alloyed with Zr, Hf, or any combination thereof to reduce the magnetic susceptibility.

[0080] Additionally, medical devices constructed from the disclosed AuPtW alloys having a tungsten (W) percentage of 10% or less by weight of the alloy can include one or more materials that impart specific properties to the device to withstand manufacturing processes used to produce the device, including, for example, laser cutting, etching, crimping, annealing, drawing, pilgering, electroplating, electropolishing, chemical polishing, cleaning, pickling, ion beam deposition or implantation, sputter coating, vacuum deposition, and the like.

[0081] It is advantageous to fabricate implantable medical devices using elongated members, such as the braided wires made of AuPtW described herein. The combination of platinum, gold, and tungsten in the AuPtW alloy provides an appropriate level of radiopacity, while gold also helps achieve a certain level of magnetic susceptibility and tungsten helps achieve a range of mechanical properties. In some applications where a higher modulus of elasticity is advantageous, W can be added to the AuPtW alloy (although the W content should be kept below 10% to avoid embrittlement). In such applications, the high Young's modulus of the AuPtW material (e.g., higher than that of W-free AuPt) allows for the fabrication of implantable medical devices with high axial (columnar) stiffness and strength. As a result, implantable medical devices can be even smaller in size (e.g., cross-sectional dimensions) than previously known devices. One example of such an implantable medical device is a vaso-occlusion device configured to be delivered to a small blood vessel to occlude an aneurysm. The small blood vessel can be any blood vessel in the body, including remote blood vessels in the patient's brain. Additionally, the high mechanical strength of the materials described herein allows implantable medical devices to be smoothly delivered using small catheters without bending, buckling, or kinking. This is true even as the size of the medical device decreases. Furthermore, the high ultimate tensile strength (UTS) of the materials allows the elongated members forming the implantable medical device to withstand less fracture or breakage during handling and processing. Furthermore, the high Young's modulus of the materials for these applications allows implantable medical devices to be manufactured using smaller elongated members to achieve a softer bending stiffness. As a result, the implantable medical device can have adequate bending stiffness and exhibit better shape retention properties.

[0082] Properties of the disclosed gold-platinum-tungsten (AuPtW) alloys for fabricating occlusive devices can include one or more exemplary properties suitable for delivery, such as column strength, tensile strength, tensile elongation, stress-strain properties, radial force, radiopacity, flexibility, pliability, thermal sensitivity, biocompatibility, etc. In particular, medical devices constructed with AuPtW alloys having a tungsten (W) percentage of 10% by weight or less can have greater device radiopacity, radial strength, hardness, yield strength, and / or ultimate tensile strength, and / or can further improve the device's stress-strain properties, crimping and / or expansion properties, bending and / or flexibility, overall device strength and / or durability, longitudinal elongation properties, recoil properties, coefficient of friction, thermal sensitivity properties, biostability, and / or biocompatibility properties. For example, medical devices having a tungsten (W) percentage of 10% or less in an AuPtW alloy can be configured to have a Young's modulus of less than 25 Mpsi. Additionally or alternatively, medical devices having a percentage of tungsten (W) in the AuPtW alloy of 10% or less can be configured to have a magnetic susceptibility of less than 300 ppm, preferably less than 200 ppm, and more preferably less than 100 ppm, thereby reducing artifacts during magnetic resonance (MR) imaging.

[0083] It should be noted that the vaso-occlusive structure 16 is not limited to having the example configuration described, and that the vaso-occlusive structure 16 can have other configurations in other embodiments. For example, in other embodiments, instead of the vaso-occlusive structure 16 having a mesh or braid, the vaso-occlusive structure 16 can have a coil configuration. FIGS. 8A and 8B show an exemplary vaso-occlusive structure in the form of an embolic coil 100, constructed in accordance with some embodiments. The coil 100 is formed of a helically wound wire 102 having a first end 104 and a second end 106. The wire 102 of the coil 100 ( FIGS. 8A and 8B ) is constructed of an AuPtW alloy with a tungsten (W) percentage of 10% by weight or less. The coil 100 includes a stretch-resistant member 108 fixedly attached to both the first end 104 and the second end 106. In alternative embodiments, the stretch-resistant member 108 may be attached to one or neither of the two ends. The coil 100 in FIG. 8A is shown with a “primary” winding or shape, while the coil 100 in FIG. 8B is shown with a “secondary” winding or shape. In some cases, the coil 100 may have a primary winding or shape when constrained within a delivery catheter and assume a secondary winding or shape when deployed outside the delivery catheter. The secondary shape of the coil 100 in FIG. 8B forms a spherical three-dimensional shape with non-overlapping loops 120. It should be understood that the secondary shape of the coil 100 may assume any other suitable shape. The wire 102 of the coil 100 may also be formed from wire, stretch-filled tubing, thread, filament, or the like. In some embodiments, as shown in FIGS. 8A and 8B, the diameter (D1) of wire 102 ranges from about 0.0005 inches (0.0127 mm) to about 0.005 inches (0.127 mm), the primary winding diameter (D2) of coil 100 ranges from about 0.003 inches (0.0762 mm) to about 0.030 inches (0.762 mm), and / or the secondary winding diameter (D3) ranges from about 0.5 mm to about 50 mm.

[0084] As previously disclosed, coils 100 constructed from the disclosed AuPtW alloys with a tungsten (W) percentage of 10% by weight or less have reduced MR artifacts due to their lower magnetic susceptibility compared to current vaso-occlusive devices.

[0085] As noted above, in some embodiments, the entire vaso-occlusive structure 16 may have a braided structure (e.g., mesh 40), with one or more (e.g., all) of the wires of the braided structure being composed of an AuPtW alloy. In other embodiments, the vaso-occlusive structure 16 may have at least one braided element and at least one non-braided element. The non-braided element may be one or more coils. In some embodiments, the non-braided element may be composed of an AuPtW alloy. Furthermore, in some embodiments, the braided structure or braid may have one or more layers of braid (e.g., braid over braid). In other embodiments, the braided structure or braid may be placed over a coil to form a braid over coil structure.

[0086] For example, in other embodiments, the vaso-occlusive structure 16 can include a mesh (or braid) and one or more coils. Figures 9 and 10 illustrate another embodiment of a vaso-occlusive treatment system 10', including a vaso-occlusive structure having a mesh 40' and coils 39a, 39b. Notably, the vaso-occlusive treatment system 10' is similar to the vaso-occlusive treatment system 10, except that the vaso-occlusive structure 16' includes a central mesh 40' and two helically wound coils 39a, 39b disposed at opposite ends of the central mesh 40'. The central mesh 40' can be configured similarly to the mesh 40 described with reference to Figures 1 and 2. Preferably, the coil portions 39a, 39b are constructed of an AuPtW alloy. Notably, the coils 39a, 39b provide additional atraumatic properties to the vaso-occlusive structure 16'.

[0087] Coils 39a, 39b function as atraumatic members to prevent vaso-occlusive structure 16' from puncturing or injuring tissue within the patient's body. In some embodiments, coils 39a / 39b can comprise coil wire having a cross-sectional dimension between 0.0001 inches (0.00254 mm) and 0.003 inches (0.075 mm), with coils 39a / 39b having a primary winding diameter between 0.003 inches (0.076 mm) and 0.030 inches (0.762 mm). Coils 39a / 39b forming the atraumatic members can have simple or complex shapes. In other embodiments, vaso-occlusive structure 16' does not need to include both coils 39a, 39b, but can include either coil 39a or coil 39b.

[0088] While the vaso-occlusive structures 16, 16' shown in Figures 1 and 2 and 9 and 10, respectively, have been described as having a single layer of braid, it should be understood that the vaso-occlusive structure can include multiple layers of braid (i.e., a braid-over-braid structure), or can include one layer of braid (e.g., an outer layer of braid) and a coil layer (e.g., an inner coil) (i.e., a braid-over-coil structure). In either case, one or more layers (e.g., all layers) of the vaso-occlusive structure are preferably composed of an AuPtW alloy.

[0089] In some embodiments, implantable medical devices made from AuPtW alloys, such as the vaso-occlusive structure 16 described herein, can have lengths of 1.2 inches (3 cm) to 19.7 inches (50 cm), preferably 2 inches (5 cm) to 11.8 inches (30 cm). Additionally, in one or more embodiments, an implantable medical device (e.g., a braid) having any of the lengths described herein is considered to have adequate column strength if, when inserted lengthwise into an elongated lumen, it can be pushed through the elongated lumen without buckling, kinking, or plastic deformation, where the elongated lumen has a maximum lumen width of 0.03 inches, preferably a maximum width of 0.016 inches, and more preferably a maximum width of 0.014 inches (e.g., 0.013 inches). The elongated lumen may be the lumen of a catheter or any elongated lumen, such as the lumen of a tube used to test the column strength of an implantable medical device.

[0090] It should be noted that the AuPtW alloys described herein should not be limited to the manufacture of vaso-occlusive devices, and the AuPtW alloys can be used to manufacture other types of medical devices. For example, the disclosed AuPtW alloys having a tungsten (W) percentage of 10 wt. % or less can be used to form devices such as stents (e.g., slotted tube stents and / or braided or woven stents), filters, thromboembolic capture devices, flow diverters, intrasaccular aneurysm implants, vascular delivery assemblies, catheters, reinforcing members, guidewires, delivery wires, radiopaque markers, and the like.

[0091] Additionally, in some embodiments, the implantable medical devices described herein are considered to have suitable shape retention properties when, when the implantable medical device has a particular initial radius of curvature R1 when inserted into a catheter and the implantable medical device has a radius of curvature R2 after being deployed from the catheter, the radius of curvature R2 of the deployed implantable medical device is less than 5 times R1, preferably less than 4 times R1, more preferably less than 3 times R1, and even more preferably less than 2 times R1 (e.g., less than 1.5 times R1, or less than 1.2 times R1, etc.).

[0092] As used herein, the term "braid" refers to any structure formed by multiple elongated members, which may or may not be woven to form the structure. In some embodiments, the braid may have a grid or mesh configuration with an open texture with spaced holes, which may form a regular, uniform pattern or a random pattern. In other embodiments, the braid may have other configurations and may or may not have an open texture. In some embodiments, the elongated members may be bonded together by mechanical forces, such as frictional forces between the elongated members. As non-limiting examples, frictional forces that bond the elongated members to form the braid may be generated by twisting the elongated members, braiding the elongated members, overlapping the elongated members, etc. In other embodiments, the elongated members may be bonded together by adhesive.

[0093] It should be noted that the term "about" as used herein refers to a variation of a value within 10% unless otherwise specified. For example, "about 10%" or less by weight refers to a weight of 10%±1% or less of the total weight.

[0094] While specific embodiments have been shown and described herein, those skilled in the art will understand that they are not intended to limit the disclosed invention. Moreover, it will be apparent to those skilled in the art that various changes, substitutions, and modifications (e.g., various part dimensions, combinations of parts) can be made without departing from the scope of the disclosed invention, which is defined by the following claims and equivalents thereof. Accordingly, the specification and drawings are to be regarded in an illustrative, and not a restrictive, sense. The various embodiments shown and described herein are intended to cover alternatives, modifications, and equivalents of the disclosed invention, which may fall within the scope of the appended claims.

Claims

1. 1. A vascular occlusion device comprising: a vaso-occlusive structure configured for implantation within an aneurysm sac, the vaso-occlusive structure being in a delivery configuration when constrained within a delivery catheter and in a deployed configuration when released from the delivery catheter into the aneurysm sac, at least a portion of the vaso-occlusive structure being comprised of an AuPtW (gold-platinum-tungsten) alloy; the AuPtW alloy comprises platinum in the range of 25 wt% to 40 wt%; A vaso-occlusive device, wherein the AuPtW alloy contains tungsten in the range of 0.01% to 10% by weight.

2. 10. The vaso-occlusive device of claim 1, A vaso-occlusive device wherein the AuPtW alloy has a Young's modulus of less than 25 Mpsi.

3. The vascular occlusion device according to claim 1 or 2, A vaso-occlusive device, wherein the vaso-occlusive structure comprises a mesh made of an AuPtW alloy.

4. The vaso-occlusive device according to claim 3, A vascular occlusion device characterized in that the mesh is braided.

5. The vascular occlusion device according to claim 3 or 4, A vascular occlusion device, characterized in that the entire vascular occlusion structure comprises the mesh.

6. The vascular occlusion device according to any one of claims 3 to 5, A vaso-occlusive device, wherein the vaso-occlusive structure further comprises two helically wound coils disposed on opposite ends of the mesh.

7. 7. The vaso-occlusive device according to claim 6, A vaso-occlusive device, characterized in that each of the two helically wound coils is constructed of an AuPtW alloy.

8. The vascular occlusion device according to any one of claims 3 to 7, A vaso-occlusive device wherein said mesh comprises at least one wire, each wire having a minimum cross-sectional dimension within the range of 0.0005 inches to 0.004 inches.

9. The vascular occlusion device according to any one of claims 3 to 8, A vaso-occlusive device wherein the mesh comprises at least one twisted wire.

10. The vascular occlusion device according to any one of claims 3 to 9, A vaso-occlusive device wherein the mesh has a wire count ranging from 8 wires to 96 wires.

11. 11. The vaso-occlusive device of claim 10, A vaso-occlusive device wherein the mesh has a wire count ranging from 16 wires to 32 wires.

12. The vascular occlusion device according to any one of claims 3 to 11, A vaso-occlusive device characterized in that when the mesh is unconstrained, the wires that make up the mesh cross each other at respective braid angles in the range of 20 degrees to 60 degrees.

13. The vascular occlusion device according to any one of claims 3 to 12, A vaso-occlusive device characterized in that the mesh has a circular cross section.

14. The vascular occlusion device according to any one of claims 3 to 12, A vaso-occlusive device characterized in that the mesh has a rectangular cross section.

15. 15. The vaso-occlusive device of claim 14, A vaso-occlusive device characterized in that the rectangular cross section has a width in the range of 0.5 mm to 5.0 mm.

16. 15. The vaso-occlusive device of claim 14, A vaso-occlusive device, wherein the mesh has a bending stiffness of less than 150 mN / mm.

17. The vascular occlusion device according to claim 1 or 2, A vaso-occlusive device, wherein the vaso-occlusive structure includes a coil made of an AuPtW alloy.

18. 18. The vaso-occlusive device of claim 17, A vaso-occlusive device, wherein the coil is configured to assume a three-dimensional shape having a plurality of loops when in an unconstrained configuration.

19. 1. A vaso-occlusive assembly comprising: The vaso-occlusive device of claim 1; a pusher member to which the vaso-occlusive device is removably coupled.

20. A vascular occlusion treatment system, comprising:

20. The vaso-occlusive assembly of claim 19; a delivery catheter in which the vascular occlusion assembly is placed.

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