Patent Description:
The present technology relates to implantable medical devices configured for embolizing a vascular site.

Implantable embolization devices may be used to embolize, e.g., occlude, a vascular site. Possible clinical applications include controlling bleeding from hemorrhages, reducing blood flow to tumors, and treating a diverse number of conditions including, for example, pathologies of the brain, the heart, and the peripheral vascular system. Among other examples, implantable embolization devices may be used to treat aneurysms, vascular malformations, arteriovenous fistulas, pelvic congestion syndrome, and varicoceles. An implantable embolization device may be configured to pack a vascular site in a patient, thereby reducing blood flow, promoting clotting, and eventually occluding the vascular site.

<CIT>, <CIT>, <CIT> and <CIT> disclose vasoocclusive devices.

Certain optional features are defined in the dependent claims. The methods described herein relating to surgical methods do not form part of the invention. In some aspects, this disclosure describes example embolization devices that include multiple sections with three-dimensional non-helical structures when deployed at a vascular site or other hollow anatomical structure of a patient. The multiple sections include a first section and one or more second sections that are configured to deploy into a smaller volume than the first section. For example, the multiple sections can include a first section and two or more second sections trailing the first section. In some cases, the different types of sections are configured to provide different features and/or capabilities. For example, in some examples, the first section may have a deployed structure configured to anchor the device in vasculature of a patient. As an example, the first section may define loops that are configured to form a scaffold inside a hollow anatomical structure (e.g., a blood vessel lumen) that holds the device in place. In some cases, the second sections define loops that are smaller than the first section loops and that can thus fit within and pack the scaffolding defined by the first section to obstruct the hollow anatomical structure.

Some example embolization devices include a third section having a deployed configuration that is different from the first and second sections. For example, an embolization device may include a third section, used for example at a leading end, that has multiple helical windings or loops configured to anchor the embolization device at a target site with a relatively high fluid (e.g., blood) flow rate anatomies.

In some aspects, this disclosure further describes assemblies for embolizing a vascular site. Also discussed are methods for delivering and deploying example embolization devices, as well as methods for forming example embolization devices.

This disclosure describes an implantable embolization device configured for embolizing a site within the vasculature of a patient or for use in another hollow anatomical structure of a patient. For example, the embolization device may be configured to pack a vascular site (e.g., a blood vessel) in a patient, thereby reducing blood flow at the vascular site. The embolization device can be used to, for example, occlude a blood vessel (e.g., a peripheral vessel) and sacrifice the blood vessel. The embolization device may also be referred to as embolic coils, occlusive coils, and/or vaso-occlusive coils. While a blood vessel is primarily referred to herein, the example embolization devices described herein may be used in other hollow anatomical structures or other vascular sites, such as, but not limited to, a splenic artery, a hepatic artery, an iliac artery a gastroduodenal artery, a peripheral aneurysm, an ovarian vein, or a spermatic vein.

The embolization devices described herein each have an elongated primary structure such as, for example, a linear wire or a coiled wire. The primary structure may also be referred to herein as the primary shape, a primary configuration, or a delivery configuration. Once deployed at the vascular site, the embolization device takes on a secondary configuration or shape, also referred to herein as a deployed configuration or a deployed shape. In the deployed configuration, the device includes at least two different sections that each define a three-dimensional ("3D") non-helical structure. The 3D non-helical structure defines a relatively complex 3D shape, such as loops in various orientations relative to each other, the loops having the same or different sizes, and does not define a simple helix. The orientation of the loops of the complex 3D non-helical structure is polyhedral, such as a tetrahedron, a hexahedron, an octahedron, or the like. The incorporation of multiple 3D non-helical structures may provide added features or benefits when compared with an embolization device without multiple 3D non-helical structures. As an example, an embolization device with multiple 3D non-helical structures, may include some such structures that are configured to anchor the device at a vascular site and other structures that are configured to pack in and more completely block the site.

A catheter delivery system is often used to place an implantable embolization device at a vascular site within a patient. A delivery system can sometimes include, for example, a microcatheter configured to be delivered to the target vascular site over a guidewire, and a positioning element (e.g., a push member, optionally with a detachment mechanism that connects to the coil) that advances one or more coils out of a lumen of the microcatheter to the vascular site. Once positioned, the coil(s) are detached from the delivery system. The coil(s) may be configured to pack (e.g., fill or otherwise occupy a space through which blood flows) the vascular site thereby reducing blood flow, promoting clotting, and eventually occluding the vessel. Different types of coils can be implanted including, for example, framing or anchoring coils and packing coils.

In many cases an embolization device may exhibit different shapes depending upon its surrounding environment. The different shapes can in some cases include a primary shape as an embolization device is delivered through the narrow confines of a catheter, and a secondary shape once deployed at a vasculature site. As an example, an embolization device may have a longitudinally extending shape as it is advanced through a catheter. Upon exiting the catheter, the device may take on a secondary shape (e.g., defining a greater cross-sectional dimension than the primary shape) within the vasculature. For example, the embolization device may exhibit a secondary shape designed to more completely pack the cross-section of the vascular site.

In some examples a first section of an embolization device and one or more second sections of the device each have a deployed configuration that defines a 3D non-helical structure formed from multiple loops of the elongated primary structure of the device. The deployed configuration of the first section is configured to anchor the embolization device in vasculature of the patient, while the deployed configurations of the one or more second sections are configured to block the vessel lumen. The loops forming the first section may in some cases be referred to as anchoring loops and may be slightly larger than the nominal vessel size for which the embolization device is designed. The first section may also be helpful in anchoring the embolization device within more elastic vessels, such as some veins, that may expand to a relatively large size. The first section may additionally be helpful in compensating for sizing errors from clinicians underestimating the sizing of the target vasculature.

The deployed configurations of the second sections may have a maximum cross-sectional dimension (e.g., a diameter or width) that is smaller than the maximum cross-sectional dimension of the deployed configuration of the first section. For example, 3D non-helical structures of the second sections may be formed from loops, in some cases referred to as packing loops, that are designed to more easily pack in the space created at the embolization site by an anchoring 3D structure. For example, the second section may be deployed at least partially (e.g., partially or fully) within the first section. Each second section is configured to deploy into a smaller volume than the first section. The deployed volume of the first section or the second section may be a function of the respective maximum cross-sectional dimension.

In some examples, the embolization devices as described herein may include a third section that is different from the first and second sections. The third section has a deployed configuration that includes multiple loops of the elongated primary structure, which may be, for example, a wire or a longitudinally extending coil (the coil itself being defined by an elongated structure formed to define a plurality of turns, e.g., winding around a central axis). The multiple loops of the third section may be helical in nature. In some examples one or more of the helical loops may have a maximum cross-sectional dimension that is slightly larger than the nominal vessel size for which the device is designed. In some examples the diameter of one or more helical loops may be approximately the same as the maximum cross-sectional dimension of the deployed configuration of the first section(s). Accordingly, the deployed configuration of the third section may be configured to provide additional anchoring of the embolization device within the patient's vasculature. In some examples, one or more of the helical loops of the third section may have a maximal cross-sectional dimension that is smaller than the nominal vessel size for which the device is designed. Accordingly, the deployed configuration of the third section may be configured to help ensure that these loops of the coil assume a deployed configuration, rather than an elongated configuration, upon exiting the delivery system. In some examples some or all of the loops of the third section may have a tapered configuration, in which the loops' diameters increase from one end toward the other end.

The third section of the device may be closest to the first section, and opposite the first section from the second sections. Accordingly, the order of the sections may extend from the third section at a leading end to the first section to the second sections at a trailing end. The leading end can be, for example, a distal end in some examples or a proximal end in other examples, and the trailing end can be, for example, a proximal end in some examples and a distal end in other examples.

When performing some vasculature embolization medical procedures, two objectives are to position an embolization device without displacement and to quickly and fully block the vessel lumen. The rate of blood flow in vessels, which can be very high in some arteries, for example, can make positioning an embolization device and occluding a vessel quite challenging, especially when compared with embolizing a space with lower flow drag forces such as, for example, an aneurysm. Example embolization devices as described herein have deployed configurations with multiple 3D non-helical structures that may be configured to address these concerns by providing a first section that anchors the embolization device in a blood vessel and one or more second sections that are configured to pack a scaffold defined by the first section. Decoupling the anchoring and packing functions of the embolization in this manner may help achieve more effective outcomes.

The embolization devices described herein may also be useful for aneurysm occlusion. In these examples, the first section can be configured to provide apposition against an aneurysm wall and the one or more second sections can be configured to pack the aneurysm sac.

As described herein, example embolization devices have a primary structure that may also be referred to as a primary shape, a primary configuration, or a delivery configuration. Example embolization devices further have a secondary configuration when deployed at a vascular site, which may also be referred to as a secondary structure or shape or a deployed configuration, shape or structure. Further, example embolization devices are described as including one or more first sections, one or more second sections (e.g., two or more second sections), and in some examples a third section. As described herein, each of these sections of an example device has its own primary configuration and secondary, e.g., deployed, configuration. These structures can alternatively be described as respective sections of a device's overall primary configuration and deployed configuration. Thus, a 3D non-helical structure may be described herein as part of the deployed configuration of the first section of an example embolization device and may alternatively be referred to as a first section of the deployed configuration of an example embolization device. For convenience, such structures may also be referred to herein as a first, second, and third deployed configurations or structures, respectively, each referring to the respective section of the device's overall deployed configuration.

<FIG> is a side view illustrating example implantable embolization device <NUM> configured to embolize a site in the vasculature of a patient. <FIG> depicts embolization device <NUM> in a secondary (or deployed) configuration that includes multiple 3D non-helical structures, which in some cases may also be referred to as complex shapes, configurations, or structures. The secondary configuration shown in <FIG> may represent the configuration of device <NUM> in its relaxed state with no external forces being applied to device <NUM>. In some cases, the material from which device <NUM> is formed may not be self-supporting, such that device <NUM> may flatten under its own weight.

Embolization device <NUM> includes a device body <NUM> that is shaped to produce the deployed configuration illustrated in <FIG>. In some examples, device body <NUM> may be a wire or other filamentous material. In some examples, device body <NUM> may be a length of coiled material. For example, device body <NUM> may be a length of coil formed from many windings or turns of a wire or other suitable material. In some examples, device body <NUM> may also incorporate other elements previously disclosed to assist in the function of a detachable coil, such as detachment elements and stretch-resistant elements.

Referring to <FIG>, embolization device <NUM> also has a primary configuration (also referred to as a delivery configuration), e.g., shape or structure, not depicted in <FIG>. As illustrated in <FIG>, device body <NUM> of embolization device <NUM> has a primary shape that is configured to fit within inner lumen <NUM> of catheter <NUM> for delivering device <NUM> to a target vasculature site <NUM>. In such cases the primary shape may be, for example, a longitudinal or lengthwise extension of device body <NUM>. As partially shown in the example of <FIG>, device body <NUM> is a length of coil extending from trailing end <NUM> to lead end <NUM>. In some examples, the coil has a primary configuration that is a substantially linear configuration within inner lumen <NUM> of catheter <NUM>. As device <NUM> is deployed from inner lumen <NUM> at a vascular site <NUM>, device body <NUM> exits catheter <NUM> and assumes its second configuration (e.g., shown in <FIG> and <FIG>). When formed from a coil, device body <NUM> may be referred to as a "primary coil" to differentiate the structure and configuration of device body <NUM> from other "secondary" loops and bends of the coil itself in a secondary configuration of the embolization devices described herein.

Returning to <FIG>, embolization device <NUM> includes first section <NUM> and one or more second sections <NUM>. Although three second sections <NUM> are shown in <FIG>, in other examples, embolization device <NUM> can include any suitable number of second sections <NUM>, such as one, two, or more than three second sections <NUM> trailing first section <NUM>.

In the deployed configuration of <FIG>, each of the first and second sections <NUM>, <NUM> include multiple loops <NUM> of device body <NUM> that form a separate 3D non-helical structure for each of the sections <NUM>, <NUM>. Loops <NUM> forming first section <NUM> may be described as first loops herein, while loops <NUM> forming each second section <NUM> may be described as secondary loops. In some examples, the 3D non-helical structure of first section <NUM> is configured to anchor the device <NUM> in vasculature of a patient and the 3D non-helical structures of second sections <NUM> are configured to pack a vascular site (e.g., a vessel lumen or an aneurysm sac) to occlude or embolize the vascular site. Accordingly, in some cases the loops forming the deployed structure of first section <NUM> may be referred to as "anchoring" loops and the loops forming the deployed structure of second sections <NUM> may be referred to as "packing" or "filling" loops. As an example, the deployed first section <NUM> may define scaffolding and the one or more second sections <NUM> may be configured to fit within and pack the scaffolding, such that the one or more second sections <NUM> tuck into first section <NUM>. An example of this configuration is shown and described with respect to FIG.

First section <NUM> has a maximum cross-sectional dimension <NUM> and each second section <NUM> has a maximum cross-sectional dimension <NUM>. Maximum cross-sectional dimension <NUM> of each second section <NUM> is smaller than maximum cross-sectional dimension <NUM> of first section <NUM>. As a result, each second section <NUM> is configured to deploy into a smaller volume than first section <NUM>. The maximum cross-sectional dimensions of embolization devices, first sections, second sections, and third sections described herein refer to the dimension of the overall structure (e.g., from edge to edge along a plane), rather than the cross-sectional dimension of the wire, coil, or other elongated structure that is used to form the respective structure.

The use of deployed second sections <NUM> with a smaller maximum cross-sectional dimension (e.g., a smaller deployed volume) than first section <NUM> may facilitate packing of the vasculature site (e.g., an aneurysm sac or a parent blood vessel). In some examples, first section <NUM> forms a scaffold within the vessel lumen or aneurysm sac as it anchors to the vessel walls at the site. Smaller maximum cross-sectional dimension <NUM> of each second section <NUM> may assist the loops forming the second sections <NUM> in packing the scaffolding provided by the first section <NUM>. In some examples, maximum cross-sectional dimension <NUM> of first section <NUM> is from about <NUM>% to about <NUM>% larger than maximum cross-sectional dimension <NUM> of each second section <NUM>, such as about <NUM>% to <NUM>% larger. When used to modify a numerical value, the term "about" is used herein may refer to the particular numerical value or nearly the value to the extent permitted by manufacturing tolerances. As an example, "about <NUM>%" means "<NUM>% or nearly <NUM>% to the extent permitted by manufacturing tolerances.

In some cases, as discussed below, maximum cross-sectional dimension <NUM> of first section <NUM> is selected based on the size of the vessel in which device <NUM> is intended to be used, and the size of maximum cross-sectional dimension <NUM> of each second section <NUM> is selected based on the determined maximum cross-sectional dimension <NUM> of first section <NUM>. For example, maximum cross-sectional dimension <NUM> of each second section <NUM> may be selected to sit inside the larger size of maximum cross-sectional dimension <NUM> of first section <NUM> when device <NUM> is deployed at a vascular site in a patient.

In some examples, embolization devices may be configured or designed to be used with blood vessels of a particular size. Thus, in some cases, a clinician may evaluate the size of vessel to be embolized and then select a specific embolization device <NUM> configured for that particular size from among multiple embolization devices as described herein, with the devices varying in size according to a range of nominal vessel sizes. In some examples, embolization device <NUM> may be configured for a particular nominal vessel size. In such examples, maximum cross-sectional dimension <NUM> may be slightly larger than the nominal vessel size. For example, maximum cross-sectional dimension <NUM> may be about <NUM> to about <NUM> times (exactly <NUM> to <NUM> or within <NUM>%) larger than the nominal vessel size, such as about <NUM> to about <NUM> times larger than the nominal vessel size or about <NUM> to about <NUM> times larger than the nominal vessel size. Too large of a maximum cross-sectional dimension <NUM>, such as larger than about <NUM> times larger than the nominal vessel size in some examples, may adversely impact the ability of the device <NUM> to form a loop within the vasculature when device <NUM> is deployed in the vasculature.

In some examples the maximum cross-sectional dimensions of second sections <NUM> may be approximately the same (e.g., the same but for manufacturing tolerances) for each second section <NUM>, or the dimensions may vary between one second section <NUM> and another second section <NUM>. In examples in which the maximum cross-sectional dimensions <NUM> are different due to, e.g., design and/or tolerances, each maximum cross-sectional dimension <NUM> is still smaller than maximum cross-sectional dimension <NUM> of first section <NUM>. In some examples, embolization device <NUM> is configured for a nominal vessel size and maximum cross-sectional dimension <NUM> is equal to or slightly smaller than the nominal vessel size. For example, maximum cross-sectional dimension <NUM> may be about <NUM>% to about <NUM>% of the nominal vessel size, or the nominal vessel size may be about <NUM> to about <NUM> times larger (e.g., exactly <NUM> to <NUM> or within <NUM>%) than maximum cross-sectional dimension <NUM>.

As described herein, example implantable embolization devices have a secondary or deployed configuration that includes multiple 3D non-helical structures. As illustrated in <FIG>, embolization device <NUM> includes first section <NUM> with a 3D non-helical structure, and three second sections <NUM>, each having a 3D non-helical structure. In some cases, 3D non-helical structures may also be referred to as complex shapes or configurations because the structures are formed from one or more loops positioned in various planes, unlike, e.g., a simpler structure such as a helical coil. First section <NUM> and/or second sections <NUM> include a 3D non-helical structure that is approximately polyhedral in that each loop of the structure approximates one of the faces of a polyhedron. In the example of <FIG>, each of the 3D non-helical structures is formed from six loops that approximate the six face planes of a cube. In some examples a 3D non-helical structure may be cubic, tetrahedral, octahedral or configured as any solid with sides shaped as a regular polygon.

In some examples, including some of those described herein, a 3D non-helical structure may be considered to approximate a sphere to a greater or lesser extent. In such cases the maximum cross-sectional dimension of each second section is an outer diameter of the second section. Further, the maximum cross-sectional dimension of a first section is an outer diameter of the first section. For example, the 3D non-helical structures exhibited by embolization device <NUM> shown in <FIG> can be considered approximately spherical such that maximum cross-sectional dimension <NUM> may be considered an outer or outside diameter <NUM> of first section <NUM>. In a similar manner, maximum cross-sectional dimension <NUM> may be considered an outer diameter <NUM> of second sections <NUM>.

The example embolization devices described herein include multiple sections with three-dimensional non-helical structures when deployed at a vascular site. The multiple sections may include at least one (e.g., one or more) first section <NUM> and at least one (e.g., one or more) second sections <NUM> that are smaller than the first section(s). Some example embolization devices may include two or more second sections that are connected to an adjacent first section. As shown in <FIG>, the deployed configuration of example device <NUM> includes three adjacent second sections <NUM> that are connected to one first section <NUM>. More or less than three adjacent second sections <NUM> may be included in some example embolization devices.

In some examples, embolization device <NUM> further includes third section <NUM> that is configured to anchor embolization device <NUM> in the patient's vasculature. As an example, third section <NUM> may be configured to anchor embolization device <NUM> along with the first deployed structure of first section <NUM>. In the deployed configuration shown in <FIG>, third section <NUM> includes multiple loops, also referred to herein as a plurality of third loops. In the example of <FIG>, third section <NUM> is connected to first section <NUM> and is positioned on an opposite side of first section <NUM> from second sections <NUM>. In some examples, the third loops forming third section <NUM> form a helical structure, e.g., a spiral structure, configured to anchor device <NUM> in the patient's vasculature. In some examples, the helical structure has a tapered configuration that increases in diameter from a leading loop <NUM> toward a trailing loop <NUM> connected to first section <NUM>, as shown in <FIG>. Alternatively, the helical structure of third section <NUM> may increase in diameter from trailing loop <NUM> towards leading loop <NUM>. In examples in which third section <NUM> has a tapered helical configuration, third section <NUM> may define a conical spiral, e.g., a three-dimensional spiral that extends along the outer surface of an imaginary cone. The spiral may taper in a leading direction (away from second sections <NUM>) in some examples, as shown in <FIG>, or may taper in a proximal direction in other examples. In some examples, the smallest loop of the spiral is smaller than the intended vessel treatment range of the device so that this section of the coil is assured to assume a deployed configuration, rather than an elongated configuration, when exiting the delivery system and deploying into the vasculature.

The loops of third section <NUM> may not be closed loops, in which the loops of the coil are coplanar and a loop of a coil touches an adjacent loop in the "at rest" state (in which no compressive forces are applied to third section <NUM> from a catheter, a blood vessel, or the like). Spacing the loops from each other in a longitudinal direction (e.g., proximal to distal direction or distal to proximal direction) may provide the loops with room to bend relative to each other and enable larger loops to decrease in cross-sectional dimension by spreading longitudinally when anchoring in a relatively small diameter vessel. In some examples, in its at rest secondary configuration, in which no outward forces are being applied to device <NUM> from a vessel wall or a catheter, the loops <NUM>, <NUM> (and other loops, if present) may be separated from each other. In addition, in examples in which loops <NUM>, <NUM> (and other loops, if present) have different maximum (or greatest) cross-sectional dimensions (e.g., diameters) from each other, each loop of third section <NUM> may differ in a maximum cross-sectional dimension from an adjacent loop by a predetermined amount. For example, if third section <NUM> is defined by an elongated structure having a diameter of <NUM>, each loop may be <NUM> larger in diameter than an immediately distal (or proximal in some examples) loop. Other loop sizes may also be used in other examples.

In examples in which third section <NUM> is closer to a leading end of device <NUM> than first section <NUM> (e.g., a distal-most section of embolization device <NUM> or a proximal-most section of embolization device in other examples), third section <NUM> may be deployed from catheter <NUM> before first section <NUM> and second sections <NUM>. For example, the first loop <NUM> of third section <NUM> may engage with the vessel wall and then subsequent loops of third section <NUM> may deform into a helix against the vessel wall, thereby potentially changing the shape of third section <NUM>, e.g., from a conical spiral to a helix having more uniform loop sizes. The helical structure of third section <NUM> may enable third section <NUM> to engage the vessel wall at distal end <NUM> of catheter <NUM> (<FIG>) and anchor at the target vascular site as embolization device <NUM> is deployed from catheter <NUM>. For example, third section <NUM> may be configured to engage the vessel wall in a relatively straight (e.g., cylindrical) vessel segment.

While first section <NUM> is also configured to engage the vessel wall to anchor embolization device <NUM> within the vasculature, the configuration (e.g., helical structure) of third section <NUM> may enable third section <NUM> to be deployed more effectively than first section <NUM>, which has smaller individual loops though a similar overall deployed outer diameter, thereby enabling embolization device <NUM> to more effectively anchor within the blood vessel as embolization device <NUM> is deployed from catheter <NUM>. The more effective anchoring of embolization device <NUM> may enable embolization device <NUM> to begin packing at or relatively close to distal end <NUM> of catheter <NUM>, rather than sliding along the vessel wall without engaging the vessel wall. The structure of embolization device <NUM> that enables it to begin packing at or relatively close to distal end <NUM> of catheter <NUM> (or other deployment location of a catheter) may provide a clinician with more precise control of the implant position of embolization device <NUM> in the vasculature of the patient, which may provide better treatment outcomes (e.g., in sacrificing the blood vessel via device <NUM>).

In some examples, the third loops forming the helical structure of third section <NUM> may further assist in anchoring device <NUM> because the third loops may be configured to exert a larger radial force against the vessel wall compared to first section <NUM> and/or second sections <NUM>. For example, helical loops may assist in penetrating the open space inside the vessel. Further, in examples in which third section <NUM> includes tapering loops, the various loop sizes defined by third section <NUM> may enable third section <NUM> to expand (as it is deployed from the catheter) to accommodate various vessel sizes (in cross-section). In these examples, embolization device <NUM> may be configured to accommodate clinician sizing preference (e.g., some clinicians may prefer a larger distal loop or a smaller distal loop based on their personal experience implanting embolization devices in patients), as well as vessel sizing uncertainty when selecting a particular size of embolization device <NUM> to implant in a patient. In some cases, embolization device manufacturers may provide embolization devices in <NUM> millimeter increments corresponding to different vessel sizes (in cross-section), e.g., <NUM> vessels, <NUM> vessels, and the like. In contrast to these devices configured for a specific vessel size, embolization device <NUM> that is configured to accommodate a range of vessel sizes may better enable a clinician to select a device <NUM> that may provide a positive outcome for the patient by requiring a less accurate determination of the patient's vessel size.

In some examples, the first <NUM> degrees of the smallest loop (e.g., loop <NUM>) defined by third section <NUM> may be selected to define a cross-sectional size that is the same size or smaller than (e.g., within <NUM>%) the cross-sectional size (e.g., diameter) of the smallest vessel a clinician may treat with embolization device <NUM>. In addition, in addition to or instead of the aforementioned parameter, in some examples, the cross-sectional size of the largest loop (e.g., loop <NUM>) defined by third section <NUM> may be selected to have a cross-sectional size that is larger than (e.g., <NUM>% to <NUM>% larger, such as <NUM>% to <NUM>% larger) the largest vessel a clinician may treat with embolization device <NUM>. By oversizing the largest loop, third section <NUM> may provide enough radially outward force to engage with the vessel wall and help anchor device <NUM> to the vessel wall.

In some examples, such as examples in which third section <NUM> defines a conical spiral, third section <NUM> may also help to center embolization device <NUM> within a vessel wall, which may enable embolization device <NUM> to achieve a higher packing density in some cases. A higher packing density may provide more effective at stopping of blood flow through the blood vessel within a given amount of time by providing a larger kinetic energy sink for the blood flow.

Third section <NUM> may be formed from any suitable material. In some examples, third section <NUM> is formed from a different material (e.g., chemical composition) than first section <NUM> and/or second sections <NUM>. In other examples, third section <NUM> is formed from the same material as first section <NUM> and/or second sections <NUM>. For example, third section <NUM> may be integrally formed with first and second sections <NUM>, <NUM>, and may be formed from the same material as first and second sections <NUM>, <NUM>. In any of these examples, third section <NUM> may be formed from a metal alloy, such as platinum tungsten (e.g., approximately <NUM>% Pt and approximately <NUM>% Tungsten), platinum, iridium, or other suitable biocompatible materials. In addition, in some examples, third section <NUM> may be at least partially formed from a material that enables third section <NUM> to engage with the vessel wall (e.g., by friction fit or using an adhesive material) for a relatively short period of time that is less than the intended implant time of embolization device <NUM>.

For example, at least part of an outer surface of third section <NUM> may be at least partially formed from a biodegradable and biocompatible hydrophilic material, such as, but not limited to poly(lactic-co-glycolic acid) (PGLA), where the biodegradable and biocompatible hydrophilic material is configured to be desiccated (dehydrated) as a result of sterilization of embolization device <NUM>. For example, third section <NUM> may be formed from a metal or fiber enlaced with or coated with PGLA or other biodegradable and biocompatible material. The PGLA or other biodegradable and biocompatible material can, for example, be formed as fibers that are enlaced with other fibers of the structure forming third section <NUM>. The state in which the biodegradable and biocompatible material of third section <NUM> is dehydrated may also be referred to as a dehydrated state of third section <NUM>.

In its dehydrated state, third section <NUM> may be configured to better stick to (e.g., by static friction) and engage with the vessel wall compared to its non-dehydrated (i.e., hydrated) state. This may due to, for example, the surface features that are more prevalent in its dehydrated state compared to the hydrated state. After embolization device <NUM> is implanted in the blood vessel, the moisture in the blood may hydrate the material of third section <NUM>, e.g., until the material reaches equilibrium with its environment. In its hydrated state, third section <NUM> may be softer compared to the dehydrated state, and may soften and engage less with the vessel wall, e.g., due to changes in the surface features, which may become less prevalent in the hydrated state. However, because embolization device <NUM> may be fully deployed at this point, first section <NUM> may provide further aid in anchoring device <NUM> in the blood vessel. In this way, the material of third section <NUM> may be used to further aid in more accurate deployment of embolization device <NUM> by anchoring device <NUM> proximate distal end <NUM> of catheter <NUM> to enable device <NUM> to pack at or relatively close to the catheter tip.

In other examples, embolization device <NUM> includes first section <NUM> and one or more second sections <NUM>, but does not include third section <NUM>.

<FIG> is a schematic diagram illustrating example assembly <NUM>, which includes embolization device <NUM> positioned within inner lumen <NUM> of catheter <NUM>. <FIG> is a schematic cross-sectional view of catheter <NUM>, where the cross-section is taken along longitudinal axis <NUM> of catheter <NUM>. Longitudinal axis <NUM> may be a central longitudinal axis of one or more components of catheter <NUM>, such as elongated body <NUM> of catheter <NUM>. Elongated body <NUM> of catheter <NUM> extends from proximal end <NUM> to distal end <NUM>. In some examples, catheter <NUM> may include strain relief member <NUM>. In such examples, proximal end <NUM> of elongated body <NUM> may be partially covered by strain relief member <NUM>, such that proximal end <NUM> of elongated body <NUM> may be more proximal than as shown in <FIG>.

Elongated body <NUM> has an outer wall <NUM> that defines lumen <NUM>. In some examples, elongated body <NUM> may define one or more additional lumens (not shown) in addition to lumen <NUM>. Such additional lumens may be used to aspirate fluid and/or deliver a drug or medical agent to a vessel. In some examples, catheter <NUM> may further include a hub <NUM> positioned at proximal end <NUM> of elongated body <NUM>. In such examples, lumen <NUM> may extend longitudinally through elongated body <NUM> to hub <NUM>. Hub <NUM> may include at least one of a first port <NUM> or a second port <NUM>, one or both of which may be in fluid communication with lumen <NUM>.

Catheter <NUM> is configured to be navigated through vasculature of a patient to deliver embolization device <NUM> to target site <NUM> within the patient's vasculature. <FIG> depicts an example in which site <NUM> is within a blood vessel <NUM> of a patient. Some example assemblies may also include a positioning device <NUM>, which may also be referred to as positioner <NUM> or a pushing member. Positioner <NUM> is configured to advance embolization device <NUM> through inner lumen <NUM> of catheter <NUM> in order to deploy device <NUM> at site <NUM>. In some examples positioning device <NUM> may also positively attach to embolization device <NUM>, and then detach from device <NUM> once it has been deployed at site <NUM>. A variety of positioning devices or positioners may be used to deliver example embolization devices described herein, including those described in <CIT>, entitled, "IMPLANT INCLUDING A COIL AND A STRETCH-RESISTANT MEMBER,".

As discussed with respect to <FIG>, example embolization devices have a primary configuration designed to fit within a catheter lumen. As shown in <FIG>, in some examples, device body <NUM> is formed from a coil that extends from trailing end <NUM> to leading end <NUM>. The coil has a substantially linear configuration within inner lumen <NUM> of catheter <NUM> as device <NUM> is configured to be advanced through inner lumen <NUM> during deployment of device <NUM> at target site <NUM> within blood vessel <NUM>. The coil exits inner lumen <NUM> of catheter <NUM> and begins to assume the secondary configuration as device <NUM> is deployed to target site <NUM>. <FIG> depicts embolization device <NUM> in the first or primary configuration, with the exception that the leading end <NUM> of device <NUM> has begun to assume the secondary configuration outside inner lumen <NUM> of catheter <NUM>. Example embolization device <NUM> includes first section <NUM>, multiple second sections <NUM>, and third section <NUM>, as also described with respect to <FIG>. For clarity, multiple second sections <NUM> are referenced in <FIG> with a single instance of reference numeral <NUM>.

In some examples the sections of example embolization devices are arranged in different manners. In <FIG>, example embolization device <NUM> includes one first section <NUM> and three second sections <NUM> that trail first section <NUM>. In some cases, the second sections <NUM> are connected to first section <NUM> and may also be adjacent first section <NUM>. Example embolization device <NUM> further includes third section <NUM> that is closer to a lead end than first section <NUM>. In some examples, third section <NUM> is connected and adjacent to first section <NUM> as depicted in <FIG>.

As depicted in the figures, example embolization device <NUM> can include three second sections <NUM> connected to one first section <NUM>, which is connected to a third section <NUM>. It will be understood that the number of the sections may be changed depending on, e.g., a particular target site, delivery method, etc. For example, in some examples, more than three or fewer than three second sections may be used. In some examples the first, second and third sections may be not be connected directly or be adjacent but may have some open length of elongated structure between sections.

<FIG> is a schematic diagram illustrating embolization device <NUM> in a deployed configuration at target site <NUM> within blood vessel <NUM>. Also shown in <FIG> is catheter <NUM> deploying one or more second sections <NUM> into a scaffold defined by first section <NUM>. In other examples, embolization device <NUM> can be deployed at other vascular sites, such as within an aneurysm sac.

First section <NUM> includes a 3D non-helical structure configured to engage with blood vessel wall <NUM> and thereby anchor device <NUM> in blood vessel <NUM>. The anchoring structure provided by first section <NUM> may be packed with the one or more second sections <NUM> of embolization device <NUM>. For example, as shown in <FIG>, first section <NUM> deployed within blood vessel <NUM> can define a scaffold (e.g., a framework including spaces) and at least part of the one or more second sections <NUM> can tuck into and pack the scaffold defined by first section <NUM> (e.g., into the spaces defined between loops or other structures of the deployed first section <NUM>). As an example, the smaller loops defined by second section <NUM> may deploy within the scaffold defined by first section <NUM>. As <FIG> illustrates, catheter <NUM> can be positioned relative to a deployed first section <NUM> such that subsequently deployed one or more second sections <NUM> are delivered within a scaffold defined by first section <NUM>.

Configuring first section <NUM> to anchor within blood vessel <NUM> or at another vascular site may result in first section <NUM> being insufficient to pack the vascular site and reduce blood flow at the vascular site. The smaller deployed volume of each one or more second section <NUM> enables the one or more second sections <NUM> to fit within and pack the scaffolding defined by first section <NUM> to help obstruct blood vessel <NUM>. Thus, by including one or more second sections <NUM> in embolization device, embolization device <NUM> can exhibit both effective anchoring at the vascular site and effective packing at the vascular site.

As described with respect to <FIG> and <FIG>, in some examples, embolization device <NUM> includes third section <NUM> connected to first section <NUM> on an opposite side of first section <NUM> from one or more adjacent second sections <NUM>. In the deployed configuration of <FIG>, third section <NUM> includes multiple helical loops that taper in diameter, increasing in diameter from end loop <NUM> (e.g., a leading loop) to beginning loop <NUM> (e.g., a trailing loop), which is connected, and adjacent, to first section <NUM>. Third section <NUM> is configured to anchor device body <NUM> in the vasculature of the patient, e.g., by engaging with wall <NUM> of blood vessel <NUM> at vascular site <NUM>.

<FIG> is a flow diagram illustrating an example method of deploying an example embolization device, such as the example embolization devices described herein. The method includes introducing catheter <NUM> into vasculature of a patient (<NUM>) and advancing catheter <NUM> to target site <NUM> (<FIG>) within the patient's vasculature (<NUM>). Once the distal end <NUM> of catheter <NUM> is at the desired position relative to target site <NUM>, a clinician may advance embolization device <NUM> through inner lumen <NUM> of catheter <NUM> (<NUM>) and deploy embolization device <NUM> at target site <NUM> (<NUM>). For example, the clinician may apply a pushing force to trailing end <NUM> of device body <NUM> (<FIG>) using positioner <NUM> or another device to deploy device body <NUM> from inner lumen <NUM> and deploy embolization device <NUM> at target site <NUM>.

Upon deploying embolization device <NUM> at the desired vascular treatment site <NUM>, device body <NUM> of embolization device <NUM> assumes a deployed configuration, e.g., as shown in <FIG>. In some examples, the deployed configuration includes a first section <NUM> that defines multiple first loops that form a 3D non-helical structure configured to anchor device body <NUM> at the treatment site and one or more second sections <NUM> that each defines multiple secondary loops that form a 3D non-helical structure. Further, in some cases each second section <NUM> has a maximum cross-sectional dimension that is smaller than a maximum cross-sectional dimension of first section <NUM>.

Embolization device <NUM> as well as other embolization devices described herein that include first section <NUM> and one or more second sections <NUM> may be formed using any suitable technique, such as by using a mandrel that includes different rods extending therefrom to define different parts of embolization device <NUM>.

<FIG> is a flow diagram illustrating an example method of forming an embolization device, such as example embolization device <NUM> shown in <FIG>. While <FIG> is described with reference to embolization device <NUM>, in other examples, the method shown in <FIG> may be used to form other embolization device including a first section and one or more second sections, as described herein. In some examples, the method includes attaching an end of an elongated structure (e.g., a wire or a coil) to a mandrel (<NUM>). For example, in some cases the elongated structure may be attached to the mandrel by inserting one end of the elongated structure into a starting hole defined by the mandrel. In some cases, the elongated structure may be stretched and wound tightly around part of the mandrel to secure the end of the elongated structure relative to the mandrel.

In some examples, the elongated structure may be a metal wire in a linear configuration or a metal wire formed into a primary coil, such as in the examples shown in <FIG>. Example embolization devices such as those described herein may be formed of any suitable, biocompatible material. In some examples, the elongated structure may be formed from a metal or metal alloy, including platinum, a platinum alloy, palladium, Nitinol, stainless steel and/or any other metal material characterized as having suitable biocompatibility.

As shown in <FIG>, the example method also includes wrapping the elongated structure about the mandrel to define first section <NUM> of embolization device <NUM> (<NUM>). For example, the elongated structure may be wrapped around the mandrel to form multiple first loops that form a 3D non-helical structure in the deployed configuration of first section <NUM>. The method also includes wrapping the elongated structure about the mandrel, e.g., one or more second winding cores extending from the main shaft of the mandrel, to define one or more second sections <NUM> of embolization device <NUM> (<NUM>). For example, the elongated structure may be wrapped around the mandrel to form multiple secondary loops forming a corresponding 3D non-helical structure in the deployed configuration of the second sections <NUM>.

After wrapping the elongated structure around the mandrel, the mandrel and the elongated structure may be heated (<NUM>) and the resulting structure remove from the mandrel (<NUM>).

In some examples, the method shown in <FIG> also includes forming a third section of embolization device <NUM>, such as by wrapping the elongated structure about the mandrel <NUM> to define form multiple third loops that are part of a tapered helical structure.

In some examples, embolization devices such as those described herein may include an elongated structure, e.g., a primary coil, that includes wires of different sizes. As an example, in some cases a primary coil may be formed with two wires of different diameters or a single wire with sections having different diameters. In some examples, a leading section of a primary coil may be formed from a wire with a larger diameter than the diameter of a wire forming a trailing section of the primary coil. In some examples, a leading section of a primary coil may be formed from a wire with a smaller diameter than the diameter of a wire forming a trailing section of the primary coil.

According to some examples, embolization devices as described herein may include one or more fibers. For example, a device may include multiple fibers, at least one bundle of fibers, or multiple fiber bundles. In some examples the fiber(s) can be enlaced, tied, or knotted to a number of places on the embolization device. In some examples the fibers or fiber bundles may be disposed so that they are not tied or knotted to the device, thereby avoiding potentially obstructive bundles that might hinder deployment of the device. In some examples one or more fibers may be nonabsorbable. Example materials that may be used include, but are not limited to, nylon, polyethylene, and/or polypropylene. In some examples, one or more fibers may be bioabsorbable. Example bioabsorbable materials that may be used include, but are not limited to, polyglycolic acid (PGA), polylactic acid (PLA), PGLA, and/or polydioxanone (PDO).

Claim 1:
A medical device (<NUM>) for embolizing a vascular site comprising:
a device body (<NUM>) comprising a first section (<NUM>) and at least one second section (<NUM>), wherein, in a deployed configuration of the device body:
the first section defines a plurality of first loops (<NUM>) forming a three-dimensional non-helical structure configured to anchor the device body in vasculature of a patient,
each second section defines a plurality of secondary loops (<NUM>) forming a three-dimensional non-helical structure, and
each second section has a maximum cross-sectional dimension that is smaller than a maximum cross-sectional dimension of the first section, characterized in that the three-dimensional non-helical structure of the first section and the three-dimensional non-helical structure of each of the one or more second sections is approximately polyhedral.