Apparatus, system, and method for coating coils

Abstract

The present disclosure relates generally to devices, systems, and methods for coil embolization, and more particularly to the use and methods of forming a coated coil. In one aspect, an embolization system can include a coil having a proximal end, a distal end, and a length therebetween, the length being slidably disposed within a sheath. A coating can be disposed about the coil. A delivery filament can be configured to be slidably disposed within the sheath proximal of the coil such that the coil can be ejected from the distal end of the sheath into a working lumen of a microcatheter. The coating can be configured to substantially break as the coil transitions from being substantially aligned with a longitudinal axis of the microcatheter to being substantially offset from the longitudinal axis of the microcatheter upon ejection from the microcatheter. The coating can be configured to plasticize upon ejection into an aqueous environment.

Description

[0001] priority

[0002] This application claims priority to and is filed under 35 USC §119 as a non-provisional application, U.S. Provisional Application Serial No. 63 / 115,898, filed November 19, 2020, the disclosure of which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] This disclosure relates generally to apparatus, systems, and methods for coil embolization, and more specifically to the use and methods of forming coated coils. Coils (such as the embolization coils described herein) may include material properties that contribute to rigidity, flexibility, thrombotic properties, antithrombotic properties, lubrication, friction, therapeutic properties, anchoring properties, etc. Background of the Invention

[0005] Therapeutic vascular occlusion (embolization) can be used for in situ prevention or treatment of pathological conditions. Embolization coils can be used to occlude blood vessels in a variety of medical applications. The preparation, delivery, and deployment of embolization coils (e.g., insertion, passage, and exit from catheters) can be difficult, depending on the size, shape, flexibility, fragility, etc., of the coil and / or associated delivery device. It is for these and other considerations that this disclosure may be useful. Summary of the Invention

[0006] In one aspect of this disclosure, the embolization system may include a microcatheter including a proximal end, a distal end, a longitudinal axis, and a working lumen therethrough. The system may include a sheath having a proximal end, a distal end, and a delivery lumen therethrough. The distal end of the sheath may be configured to be insertable into the working lumen at the proximal end of the microcatheter. The system may include a coil having a proximal end, a distal end, and a length therebetween, the length being slidably disposed within the sheath. A coating may be disposed around the coil. A delivery filament may be configured to be slidably disposed within the sheath adjacent to the coil, such that the coil can be discharged from the distal end of the sheath into the working lumen of the microcatheter. The delivery filament may be configured to be slidably disposed within the working lumen of the microcatheter adjacent to the coil, such that the coil can be discharged from the working lumen at the distal end of the microcatheter into a target site. The coating may be configured to break off substantially as the coil transitions from being substantially aligned with the longitudinal axis of the microcatheter to being substantially deviated from the longitudinal axis of the microcatheter during discharge from the microcatheter, or the coating may be configured to plasticize after discharge from the distal end of the sheath into an aqueous environment.

[0007] In the various embodiments described herein or otherwise within the scope of this disclosure, the coil may include a primary shape and a secondary shape, the primary shape being generally linear when disposed within a microcatheter and the secondary shape being generally curved when exiting the microcatheter to a target site. The coating may be configured to substantially break off from the coil as it transitions from the primary shape to the secondary shape. The coating may be made of a hydrophilic polymer having a number-average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol. The coating may be disposed around the outer surface of the coil. The coil may include a polymer, and the coating may include at least one of polyvinylpyrrolidone, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, polyacrylamide, hydroxypropyl methacrylamide, and polyamide. The coating may include a hydrophilic polymer, and wherein the coating is configured to substantially break off upon exiting the microcatheter. The coil may include a polymer, and the coating may include at least one of xanthan gum, pectin, chitosan, sodium alginate, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hyaluronic acid, dextran, carrageenan, guar gum, cellulose ether, albumin, starch, polylactic acid homopolymer, polyglycolic acid homopolymer, copolymer of lactic acid, copolymer of glycolic acid (PLGA), polycaprolactone, polyhydroxybutyric acid, polyhydroxyalkanoic acid, and aliphatic polyester. The coating may include a hydrophobic polymer, and the coating is configured to plasticize after being discharged from the distal end of the sheath into an aqueous environment. The coil may include a prothrombotic factor covered by the coating. The delivery filament may include a distal end reversibly coupled to the proximal end of the coil. At least one fiber may be coupled to the coil and disposed within the coating.

[0008] In one aspect of this disclosure, the embolization coil may include coil filaments arranged in adjacent windings about a longitudinal axis. A coating may be disposed around the coil. The coating may be a fragile coating configured to break off from a portion of the coil winding as a portion of the coil transitions from being substantially aligned with the longitudinal axis of the rest of the coil, or wherein the coating may be configured to plasticize after being discharged into an aqueous environment.

[0009] In the various embodiments described herein or otherwise within the scope of this disclosure, the coating may include at least one of polyvinylpyrrolidone, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, polyacrylamide, hydroxypropyl methacrylamide, and polyamide. The coating may include a hydrophilic polymer, and wherein the coating is a fragile coating configured to break as a portion of the coil transitions from being substantially aligned with the longitudinal axis of the remainder of the coil. The fragile coating may include at least one of xanthan gum, pectin, chitosan, sodium alginate, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hyaluronic acid, dextran, carrageenan, guar gum, cellulose ether, albumin, starch, polylactic acid homopolymer, polyglycolic acid homopolymer, copolymers of lactic acid, copolymers of glycolic acid (PLGA), polycaprolactone, polyhydroxybutyric acid, polyhydroxyalkanoic acid, and aliphatic polyesters. The coating may include a hydrophobic polymer, and wherein the coating is configured to plasticize upon discharge into an aqueous environment. The coil filament may include a primary shape and a secondary shape, the primary shape being generally linear and the secondary shape being generally curved. The coating may be configured to break substantially from the coil filament as it transitions from the primary shape to the secondary shape. When disposed around a winding, the coating may be generally insoluble. When breaking from the winding, the coating may be generally soluble. The coating may have a lower coefficient of friction compared to the coil filament. The sheath may include a proximal end, a distal end, and a delivery lumen therethrough. The coil is slidably disposed within the sheath. The fragile coating may include a hydrophilic polymer having a number-average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol.

[0010] In one aspect of this disclosure, a method of forming a coil may include winding coil filaments into adjacent windings around a longitudinal axis. The coil filaments may be immersed in a container holding a fluid comprising a hydrophilic polymer having a number average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol. One end of the coil filament may be lifted out of the container until the opposite ends of the coil filament rise out of the fluid.

[0011] In various embodiments described herein or otherwise within the scope of this disclosure, lifting the end of the coil filament may further include holding the end of the coil filament such that it is substantially aligned with each of the longitudinal axis of the coil filament and each of the opposite ends. Adjacent windings of the coil filament may be configured in a secondary shape. The fluid may include at least one of polyvinylpyrrolidone, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, polyacrylamide, hydroxypropyl methacrylamide, and polyamide. The fluid may include a hydrophilic polymer, and the coating is configured to substantially break upon discharge from the microcatheter. The fluid may include at least one of xanthan gum, pectin, chitosan, sodium alginate, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hyaluronic acid, dextran, carrageenan, guar gum, cellulose ether, albumin, and starch. The fluid may include a hydrophobic polymer, and the coating is configured to plasticize after discharge from the distal end of the sheath into an aqueous environment. Brief description of the attached diagram

[0013] Non-limiting embodiments of this disclosure are described by way of example with reference to the accompanying drawings, which are schematic and not intended to be drawn to scale. In the drawings, each equivalent or nearly equivalent component shown is generally indicated by a single reference numeral. For clarity, not every component is labeled in every drawing, and not every component of each embodiment is shown where the illustrations are not essential for allowing those skilled in the art to understand that this disclosure is not essential. In the drawings:

[0014] Figure 1 An embodiment of the present disclosure schematically illustrates a deployed embolization coil.

[0015] Figure 2A An embolism coil immersed in fluid is schematically illustrated according to an embodiment of the present disclosure.

[0016] Figure 2B The schematic diagram illustrates the removal from the fluid. Figure 2A Plug coil.

[0017] Figure 3A The fabrication of an embolization system is schematically illustrated according to embodiments of the present disclosure. The embolization system includes a sheath comprising an embolization coil introduced into a microcatheter.

[0018] Figure 3B Embodiments of this disclosure are illustrated schematically. Figure 3A The delivery filament within the sheath of the embolization system.

[0019] Figure 3C According to embodiments of this disclosure, the delivery at a first time point is illustrated schematically. Figure 3A The coil of the embolization system.

[0020] Figure 3D According to embodiments of this disclosure, the delivery at a second time point is illustrated schematically. Figure 3A The coil of the embolization system.

[0021] Figure 3E An embodiment of this disclosure schematically illustrates the deployment at a third time point. Figure 3A The coil of the embolization system.

[0022] Figure 4 An embodiment of the present disclosure schematically illustrates a deployed embolization coil with a hydrophobic coating.

[0023] Figure 5 An embodiment of the present disclosure schematically illustrates a deployed embolization coil with a hydrophobic coating.

[0024] Figure 6 An embolization coil with a hydrophilic coating is schematically illustrated according to an embodiment of the present disclosure. Detailed Implementation

[0025] This disclosure is not limited to the specific embodiments described. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope beyond the appended claims. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0026] Although embodiments of this disclosure may be described with specific reference to medical devices and systems (e.g., intravascular embolization devices and / or accessories, etc.), it should be understood that such medical devices and systems can be used for occlusion, fixation, stenting, etc., in serious medical procedures. The medical devices described herein may include a variety of medical devices for navigating patient anatomy, including, for example, catheters, microcatheters, visualization devices (e.g., fluoroscopy, ultrasound, X-ray, endoscopy, etc.), which can be inserted via various access points and methods, such as percutaneous, endoscopic, laparoscopic, or combinations thereof.

[0027] As used herein, the term "coil" is intended to include occlusion devices such as those used for embolization. Such occlusion devices may be intended for use in aneurysms, blood vessels, tumors, other blood vessels, or other body lumens.

[0028] As used herein, the singular forms “an,” “a,” and “the” are intended to also include the plural forms unless the context clearly indicates otherwise. The terms “comprises” and / or “comprising,” or “includes” and / or “including” as used herein specify the presence of the stated features, steps, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0029] As used herein, “proximal end” refers to the end of a device that is closest to a medical professional along the device when the device is introduced into the patient; and “distal end” refers to the end of a device or object that is furthest from a medical professional along the device during implantation, positioning, or delivery.

[0030] As used herein, the conjunction “and” includes each of such joined structures, parts, features, etc., unless the context clearly indicates otherwise; and the conjunction “or” includes one or the other of such joined structures, parts, features, etc., individually and in any combination and number, unless the context clearly indicates otherwise.

[0031] All numerical values ​​herein are assumed to be modified by the term “about”, whether explicitly indicated or not. In the context of numerical values, the term “about” generally refers to a range of numbers that those skilled in the art will understand to be equivalent to the listed numerical values ​​(i.e., having the same function or result). In many cases, the term “about” may include numbers rounded to the nearest significant figure. Other uses of the term “about” (i.e., in contexts other than numerical values) may be assumed to have their common and customary definitions, as understood and consistent with the context of this specification, unless otherwise specified. A range of numerical values ​​expressed by endpoints includes all numbers within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0032] It should be noted that references to "one embodiment," "some embodiments," "other embodiments," etc., in the specification indicate that one or more embodiments described may include a specific feature, structure, or characteristic, but each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, such references may not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in conjunction with one embodiment, those skilled in the art will understand that such features, structures, or characteristics will also apply in conjunction with other embodiments (whether explicitly described or not), unless explicitly stated to the contrary. That is, the various individual elements described below, even if not explicitly shown in a specific combination, are contemplated as combinable or arrangeable to form other additional embodiments or to supplement and / or enrich the described embodiments, as will be understood by those skilled in the art.

[0033] refer to Figure 1 According to one embodiment of the embolization system of this disclosure, coil 100 is shown deployed into aneurysm 120. The system shown includes a microcatheter 110 extending within a vessel 122, wherein the distal end 110d of the microcatheter 110 is oriented toward the aneurysm 120 for treatment. For example, the distal end 110d of the microcatheter 110 can be manipulated under observation conditions by making the radiopaque zone 112 visible via other possible techniques such as fluorescence microscopy. Coil 100 is being deployed distally from the microcatheter 110 to substantially fill a volume of the aneurysm 120.

[0034] In the various embodiments described herein, the coil may be desirablely flexible for deployment and aneurysm filling. However, such flexible coils may present several problems during delivery through a microcatheter; for example, the coil may sag, bend, or be crushed due to proximal members axially pushing the coil distally through the microcatheter. These problems can be addressed by applying the coating described herein to the coil, which has greater axial stiffness compared to the underlying coil. This facilitates the coil's maneuverability through the microcatheter, thereby reducing these problems. However, such stiffness may be undesirable during coil deployment, for example, into an aneurysm. Therefore, it is desirable that the coil substantially loses its coating during deployment after the coil has been delivered through the microcatheter.

[0035] In the various embodiments described herein, the coil may include a coating disposed around the outer surface of the coil, around all surfaces of the coil, and / or disposed within and throughout the coil. The coating may include a material that temporarily alters the properties of the coil, for example, for preparation, delivery, and / or deployment. These properties may include therapeutic properties (such as drug delivery) or properties that may aid, inhibit, or accelerate bodily functions (e.g., thrombosis). The coating may reduce friction on the coil during delivery, for example, by including lubrication or reducing surface area, such as encapsulating and / or repositioning fibers extending from the coil. Such coatings may remain on the coil for an extended period of time, or alternatively may be bio-soluble, fragile, or soluble, such that the coating is removed from the coil during or shortly thereafter during preparation, delivery, and / or deployment (e.g., before removal of the microcatheter used to deliver or deploy the coil).

[0036] refer to Figure 2A According to one embodiment of the method of this disclosure, a coating is formed on coil 200. Coil 200 is immersed in fluid 220 contained in reservoir 222. Fluid 220 comprises the material described herein, which is intended to coat coil 200. Coil 200 may be uniformly immersed in fluid 220 such that fluid 220 contacts or adheres to substantially all outer surfaces of coil 200 before coil 200 contacts the bottom 222b of reservoir 222 and / or before coil 200 contacts itself. Coil 200 may be immersed in reservoir 222 such that multiple portions of coil 200 have minimal contact with sides 222s of reservoir 222, which may help maximize contact between fluid 220 and the surfaces of coil 200. The entire length of coil 200 may be immersed in fluid 220 such that substantially all surfaces or all exposed or outer surfaces of coil 200 contact fluid 220. The length of coil 200 can be immersed for a certain period of time, so that fluid 220 covers, adheres to and / or binds to coil 200.

[0037] refer to Figure 2B This shows that it was formed in Figure 2A The coating on the coil 200, wherein the coated coil 200 is removed from the reservoir 222. The coil 200 is completely immersed in the fluid 220 (i.e., via...). Figure 2AThe process involves ensuring that the surface of coil 200 is in full contact with fluid 220. Coil 200 can be removed from fluid 220 by gripping the end of coil 200 with clamp 234 and lifting coil 200 away from fluid 220 in reservoir 222. Clamp 234 is coupled to arm 230 of gantry system, which allows arm 234 to be vertically translated along track 232. Clamp 234 is positioned vertically above reservoir 222, such that further contact between coil 200 and reservoir 222 is largely avoided as coil 200 rises from reservoir 222. As coil 200 rises from fluid 220, portion 200p of coil 200 is exposed to the atmosphere and aligned longitudinally along its length above reservoir 222. This longitudinal alignment forms a generally straight coating coil 200 and allows some fluid 220 to flow along the length of the coil 200 for coating as the fluid 220 dries and / or bonds, and / or to flow by gravity into the reservoir 222. The coil 200 can be removed from the fluid 220 at a uniform rate (e.g., vertically rising along the length of the coil 200 at a rate of about 1 mm / s to about 25 mm / s, which can be varied by the desired coating thickness, the percentage of solids in the fluid or coating, viscosity, etc.). The coil 200 can be completely removed from the fluid 220 and held above the reservoir 222 by a clamp 234 such that the coating is formed along the length of the coil 200, wherein the coil 200 is generally straight along its longitudinal axis (e.g., wherein once fully risen, the ends of the coil 200 are vertically positioned on opposite ends of the coil 200). The coil 200 may be held on the reservoir 222 by the clamp 234 for a period of time, allowing the coating to fully form (e.g., fully dry, cure, etc., for a period of time, for example, from about 30 minutes to about 4 hours, at room temperature, which can be reduced, for example, by increasing the temperature using an online IR lamp (e.g., from about 60°C to about 100°C) or by transferring the coil 200 to a convection oven (e.g., from about 40°C to about 100°C) for, for example, about 15 minutes to about 1 hour). Although an immersion coating (i.e., dip coating) process is shown, in the various embodiments described herein, the coil may be coated by alternative methods, such as solvent coating, spraying, coating with a brush or other applicator, etc.

[0038] In the various embodiments described herein, a coil may be prepared into a winding from filaments along the length of the coil and through its longitudinal axis, for example, on a mandrel. These filament windings may form, for example, the primary shape of the coil, wherein the windings are formed generally linearly along the longitudinal axis. Adjacent windings may contact each other, or they may include a gap between them. Adjacent windings may adhere to each other, for example, via melt flow, adhesion, adhesive, coating, etc. The primary shape may be formed into a secondary shape, such as a helix, sphere, cone, curved shape, layered shapes spaced apart or overlapping each other, spiral shape, combinations thereof, etc. The secondary shape may be formed, for example, on a mandrel and heat-set, such that the secondary shape deforms within the coil to form the secondary shape, for example, when the coil is in a free state rather than under tension or constraint, for example, within a sheath, microcatheter, coating, etc. The coating described herein may be formed on the filaments of the coil before the filaments are formed, after the formation of the primary shape of the coil, or after the formation of the secondary shape of the coil. The coating may be continuous within the windings of the coil.

[0039] In the various embodiments described herein, the filament of the coil may comprise one or more materials, such as polymers comprising synthetic polymers, natural polymers, crosslinked polymers, non-crosslinked polymers, thermosetting polymers, and / or thermoplastic polymers. Examples of polymers include polyolefins; polyurethanes; block copolymers (e.g., block copolymers having segments comprising esters, ethers, and / or carbonates); polyethers; polyimides; acrylates (e.g., cyanoacrylates); epoxy resin adhesive materials (e.g., one-component epoxyamine materials, two-component epoxyamine materials); polymers and / or copolymers of ethylene, propylene, butadiene, styrene, and / or thermoplastic olefin elastomers; polydimethylsiloxane polymers; rayon; cellulose; cellulose derivatives. (e.g., nitrocellulose); natural rubber; polyesters (e.g., polyethylene terephthalate); polylactide; polyglycolic acid; polycaprolactone; copolymers of lactic acid, glycol esters and / or caprolactone; polyhydroxybutyrate, polyhydroxyvalerate, and copolymers of hydroxybutyrate and hydroxyvalerate; polyether esters (e.g., polydioxane); polyanhydrides, polymers and copolymers of dicarboxylic acids such as sebacic acid, hexadecanoic acid and other dicarboxylic acids; orthoesters; polyamino acids; polynucleotides; polysaccharides; and polyhydroxyalkanoates. In various embodiments, the filaments may comprise one or more mixtures and / or copolymers of these materials (e.g., block copolymers, random copolymers). In various embodiments, the coil may comprise one or more fibers extending from the coil to facilitate coagulation or occlusion and may comprise one or more filament materials described herein.

[0040] In the various embodiments described herein, the coating or the fluid forming the coating may comprise one or more materials, such as one or more polymeric materials, as listed below. In some embodiments, the solid and / or brittle coating may be insoluble and may harden the coil for delivery, and the coating may be fragile such that it may break off from the coil into particles upon deployment, and these particles may be soluble and biocompatible when absorbed or passed through the body. The coating may be made of a generally water-insoluble hydrophobic polymer having a number average molecular weight of about 1,000 g / mol to about 100,000 g / mol. In the presence of blood, the hydrophobic polymer may be biodegradable, wherein the polymer degrades generally, for example, within a range of about 1 week to about 1 month. The coil may comprise a polymer, and the coating may comprise at least one of polylactic acid homopolymer, polyglycolic acid homopolymer, copolymer of lactic acid and glycolic acid (PLGA), polycaprolactone, polyhydroxybutyrate, polyhydroxyalkanoate, and aliphatic polyester. The coating may have a component such that it breaks when the coil moves generally outside its longitudinal axis (e.g., at least a portion of the coil moves away from its longitudinal alignment or primary shape) and / or generally outside the longitudinal axis of the microcatheter or sheath. For example, the coating may include one or more hydrophilic polymers. For example, the coating may include one or more of the following: polyvinylpyrrolidone polymers or copolymers, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, copolymers of polyacrylamide, copolymers of hydroxypropyl methacrylamide, polyamide, xanthan gum, pectin, chitosan derivatives, sodium alginate, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hyaluronic acid, dextran, carrageenan, guar gum, cellulose ethers, albumin, starch, starch-based derivatives, etc. In some embodiments, the component may include a hydrophilic polymer having a number-average molecular weight in the range of about 10,000 g / mol to about 1,000,000 g / mol. In some advantageous embodiments, the coating may be formed from a polyvinylpyrrolidone (PVP) polymer having a number-average molecular weight in the range of about 10,000 g / mol to about 1,000,000 g / mol.

[0041] refer to Figure 3AAn embodiment of the embolization system is shown to include a sheath 302 comprising a coated embolization coil 300 introduced into the working lumen of a microcatheter 310. The sheath 302 may protect the coil 300 in a packaging device (e.g., from trauma or abrasion) and may facilitate the fabrication of the coil 300 for patient delivery. The coated coil 300 is in a primary shape generally aligned along its length, with a longitudinal axis l extending through the microcatheter 310. The distal end of the sheath 302, including the coil 300, extends at the proximal end of the microcatheter 310 through an access hub 306. The outer diameter of the sheath 302 may generally match the inner diameter of the microcatheter 310, such that the distal end of the sheath 302 is securely seated within the proximal end of the microcatheter 310. Alternatively, the outer diameters of the sheath 302 and the microcatheter 310 may generally match, such that they are abutted against each other. Figure 3A In the configuration shown, the coil 300 is freely slidable from the delivery lumen of the sheath 302 into the microcatheter 310, for example, generally along the longitudinal axis l.

[0042] refer to Figure 3B , showed Figure 3A The embolization system includes a sheath 302, in which a delivery filament 304 extends slidably into the proximal end of the sheath 302. A coil 300 can be delivered from within the sheath 302 by a medical professional 350 via distal translation of the delivery filament 304. Figure 3A The delivery filament 304 is further translated into the sheath 302 within the microcatheter 310. Further translation of the delivery filament 304 into the sheath 302 will result in further delivery of the coil 300 into the microcatheter 310. The insertable length of the delivery filament 304 is substantially matched to the length of the delivery sheath 302, such that the distance L between the proximal end of the delivery filament 304 and the proximal end of the sheath 302 is substantially equal to the length of the coil 300 held within the sheath 302 (i.e., where the remaining length of the coil 300 is within the microcatheter 310). As the proximal end of the delivery filament 304 approaches the proximal end of the sheath 302 (e.g., when L is approximately 10 cm, etc.), the user 350 may stop translating the delivery filament 304 into the sheath 302 and may withdraw the sheath 302 proximally along the delivery filament 304 until the sheath 302 is removed from the system. The user 350 can then further translate the delivery filament 304 through the hub 306 and into the microcatheter 310 to further deliver, discharge, and / or deploy the coil 300 without losing the delivery filament 304 within the sheath 302 if the sheath 302 is not removed proximally.

[0043] Figure 3C It shows Figure 3A and Figure 3B The embolization system includes a coil 300, which is delivered and deployed into the aneurysm 320. The coil 300 includes a coating 308. Via... Figure 3BThe delivery filament 304 is generally translated along the longitudinal axis l of the microcatheter 310 and / or the proximal portion of the coil 300 through the distal side of the microcatheter 310, and the coated coil 300 is translated distally through the microcatheter 310. As the distal end 300d of the coil 300 extends distally away from the microcatheter 310 through a visible distal marking band 312, for example, a ray-impermeable distal marking band 312 that can be visualized via a fluorescence microscope, the distal end 300d is partially free to move away from (i.e., substantially deviate from) the generally aligned longitudinal axis l of the microcatheter 310 and / or the proximal portion of the coil 300. In the various embodiments described herein, a portion of the coil may move away from the generally aligned longitudinal axis by, for example, fluid flow, gravity, fluid contact, tissue contact, medical device contact, random chance, or a combination thereof. As the distal end 300d of the coil 300 and the coating 308 move away from the microconduit 310 and away from their approximate alignment with the longitudinal axis l, a portion 308d of the brittle coating 308 breaks off from the coil 300 and fragments into particles 308e; however, as referenced herein... Figures 4 to 6 As discussed, similar or alternative coating transitions may occur. As the coating 308 breaks off from the coil 300, the properties of the coil 300 can be altered, as described herein. For example, the coating 308 on the coil 300 can increase the stiffness of the coil 300, making it easier for the coil 300 to be pushed through the microcatheter 310 by the delivery filament 304, and as the coating 308 breaks off from the distal end 300d of the coil 300, the coil 300 can become more flexible for deployment in the aneurysm 320. Furthermore, as the coating 308 breaks off from the coil 300 into particles 308e, the materials of both the coating 308 and the coil 300 can be exposed to the body, such as thrombosis accelerators, thrombotic fibers, etc., as described herein.

[0044] Figure 3D It shows Figures 3A to 3CThe coil 300 of the embolization system is further delivered and deployed into the aneurysm 320. A delivery wire 304 is translated distally through the microcatheter 310, wherein the distal end of the delivery wire 304 abuts the proximal end of the coil 300. As the coil 300 continues to translate distally away from the microcatheter 310 and substantially away from alignment with the longitudinal axis l, portions 308d of the coating 308 on the exterior of the microcatheter 310 continuously break and fragment into particles 308e, allowing the coil 300 to further detach from the coating 308 during deployment into the aneurysm 320. As the delivery filament 304 approaches a distance X from the distal end of the marking band 312, a medical professional operating the system can observe that the coil 300 is nearly fully deployed away from the microcatheter 310 (e.g., by employing a delivery filament 304 that is impermeable to radiation visible through a fluoroscope); or it can be inferred from the length of the delivery filament 304 (which has been translated distally through the microcatheter 310) that the coil 300 is nearly fully deployed away from the microcatheter 310. The distance X can be of various lengths, such as approximately 1 cm. With the coil 300 nearly fully deployed, a medical professional can reposition the coil 300 as needed by manipulating the microcatheter 310 and / or translating the delivery filament 304. In the various embodiments described herein, the delivery filament 304 and the coil 300 may be temporarily coupled to each other during delivery, such that distal and proximal translation of the delivery filament 304 also translates the coil 300 in a similar manner, thereby allowing complete proximal removal and disposal of the delivery filament 304 and the coil 300 in cases where repositioning is difficult. For example, the delivery filament 304 may have a geometry that is substantially interlocked with the complementary geometry of the coil, such as a channel, a C-shaped link, etc.

[0045] Figure 3E It shows Figures 3A to 3D The embolization system coil 300 is fully deployed into the aneurysm 320. Once the majority of the coil 300 is confirmed to be in place... Figure 3D If the desired deployment location is desired, the delivery filament 304 can be translated distally through the marking band 312 at the distal end of the microcatheter 310 for complete deployment of the coil 300 (i.e., discharge of the coil 300 from the microcatheter 310). The remaining portion 308d of the coating breaks off from the coil 300 into particles 308e, allowing the intact coil 300 to detach from the coating for deployment into the aneurysm 320. If the delivery filament 304 is attached to the coil 300, the delivery filament 304 can be manipulated, such as by rotation, agitation, etc., to disengage the coil 300 from the delivery filament 304 outside the microcatheter 310. After the deployment of the coil 300, if desired, additional coils can be delivered and deployed through the microcatheter 310 in a similar manner, for example, to further fill the aneurysm 320.

[0046] Reference Figure 4 and Figure 5 In the various embodiments described herein, the coatings 408, 508 of the coils 400, 500 may be transitioned in various ways as the coils 400, 500 are deployed. For example, refer to... Figure 4 A coating 408, comprising a hydrophobic material, can be substantially rigid during delivery within a microcatheter 410 (and / or sheath or other elongated member, not shown), thereby allowing the coil 400 to advance distally without sagging. As the coating 408 (i.e., the brittle coating) extends distally away from the microcatheter 410, portions 408d of the coating 408 substantially deviate from the microcatheter 410, and / or the proximal remainder of the coating 408 breaks off from the coil 400 into particles 408e, thereby allowing the coil 400 to detach from the coating 408 (e.g., for deployment). The particles 408e break off from the coil 400 because the coating 408 is not substantially adhered to the coil 400. Alternatively, refer to Figure 5 The coating 508 can generally adhere to the coil 500 such that as a portion 508d of the coating 508 extends distally away from the microconduit 510 and deviates from the microconduit 510 and / or the proximal remainder of the coating 508, the portion 508d cracks along the coil 500 into at least a partially disengaged portion 508e (i.e., the brittle coating portion 508d cracks, making it less rigid than before cracking), thereby allowing the coil 500 to detach from the cracked coating 508e. The portion 508d of the coating cracks but generally remains along the coil 500 because the coating 508 is generally adhered to the coil 500. Such hydrophobic coatings 408, 508 can be more rigid (e.g., glassy) in a generally dry state and can be rapidly plasticized without the aid of a fluid. Such hydrophobic coatings 408 and 508 may crack during the deployment of coils 400 and 500; and if there is a strong adhesive force between the coatings 408 and 508 and the coils 400 and 500, then the coatings 408 and 508 may remain substantially along the deployed coils 400 and 500. If the coatings 408 and 508 do not substantially adhere to the coils 400 and 500, then the coatings 408 and 508 may substantially break off from the deployed coils 400 and 500, biodegrade, and pass through or be metabolized within the body during or after deployment.

[0047] refer to Figure 6In the various embodiments described herein, the coating 608 of the coil 600 may dissolve as the coil 600 is deployed. The coating 608 along the coil 600 comprises a hydrophilic material that may be substantially rigid during delivery within the microcatheter 610 (and / or sheath or other elongated member, not shown), thereby allowing the coil 600 to advance distally through the microcatheter 610 without sagging. As the coating 608 extends distally away from the microcatheter 610, portions 608d of the coating 608 are substantially exposed to and / or saturated in an aqueous fluid (e.g., blood). Portions 608d of the coating 608 disperse from the coil 600 into particles 608e and / or a solution, thereby allowing the coil 600 to detach from the coating 608 and flex for deployment. Such a hydrophilic coating 608 may be more rigid (e.g., glassy) in a substantially dry state and may be rapidly plasticized by fluids, thereby reducing stiffness. The duration for which coating 608 plasticizes to the desired flexibility in the fluid may depend on the composition of coating 608. In some embodiments, coating 608 may be peeled off from the coil during and / or after coil 600 deployment.

[0048] According to this disclosure, all the apparatuses and / or methods disclosed and claimed herein can be made and performed without much experimentation. Although the apparatuses and methods of this disclosure have been described according to preferred embodiments, it will be apparent to those skilled in the art that variations may be applied to the apparatuses and / or methods described herein, as well as the steps or sequences of steps of the methods, without departing from the spirit and scope of this disclosure. All such similar alternatives and modifications that are apparent to those skilled in the art are considered to be within the spirit, scope, and spirit of this disclosure as defined by the appended claims.

Claims

1. An embolization system comprising: a microcatheter including a proximal end, a distal end, a longitudinal axis, and a working lumen therethrough; a sheath including a proximal end, a distal end, and a delivery lumen therethrough, the distal end of the sheath configured to be insertable within the working lumen at the proximal end of the microcatheter; a coil including a proximal end, a distal end, and a length slidingly disposed within the sheath therebetween; a coating disposed about the coil; and a delivery filament configured to be slidingly disposed within the sheath proximal to the coil such that the coil is expellable from the distal end of the sheath into the working lumen of the microcatheter, and configured to be slidingly disposed within the working lumen of the microcatheter proximal to the coil such that the coil is expellable from the working lumen at the distal end of the microcatheter to a target site; wherein the coating is configured to substantially break apart as the coil transitions from being substantially aligned with the longitudinal axis of the microcatheter to being substantially misaligned with the longitudinal axis of the microcatheter upon expulsion from the microcatheter, wherein the coil includes a primary shape that is substantially linear when disposed within the microcatheter and a secondary shape that is substantially curvilinear when expelled from the microcatheter to the target site, and wherein the coating is configured to substantially break apart from the coil as the coil transitions from the primary shape to the secondary shape.

2. The embolization system of claim 1, wherein the coating is made from a hydrophilic polymer having a number average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol.

3. The embolization system of any one of claims 1-2, wherein the coating is disposed about an outer surface of the coil.

4. The embolization system of any one of claims 1-2, wherein the coil includes a polymer and the coating includes a hydrophilic polymer, and wherein the coating is configured to substantially break apart upon expulsion from the microcatheter.

5. The embolization system of any one of claims 1-2, wherein the coil further includes a thrombogenic factor covered by the coating.

6. The embolization system of any one of claims 1-2, wherein the delivery filament includes a distal end reversibly coupled to the proximal end of the coil.

7. The embolization system of any one of claims 1-2, further comprising at least one fiber coupled to the coil and disposed within the coating.

8. An embolic coil comprising: a coil filament arranged in adjacent windings about a longitudinal axis; and a coating disposed about the windings, wherein the coating is a frangible coating configured to break apart as a portion of the coil transitions from being substantially aligned with the longitudinal axis of the remainder of the coil, 9. The embolic coil of claim 8, wherein the frangible coating is configured to break apart as the portion of the coil transitions from being substantially aligned with the longitudinal axis of the remainder of the coil to being substantially misaligned with the longitudinal axis of the remainder of the coil. wherein the coil filament includes a primary shape and a secondary shape, the primary shape being substantially linear, the secondary shape being substantially curvilinear, and wherein the coating is configured to substantially break away from the coil filament as the coil filament transitions from the primary shape to the secondary shape.

9. The embolic coil of claim 8, wherein the coating includes a hydrophilic polymer, and wherein the coating is configured to break away as the portion of the coil transitions from being substantially aligned with the longitudinal axis of the remainder of the coil.

10. The embolic coil of any one of claims 8 to 9, wherein the coating is substantially insoluble when disposed about the winding, and the coating is substantially soluble when broken away from the winding.

11. The embolic coil of any one of claims 8 to 9, wherein the coating has a lower coefficient of friction than the coil filament.

12. The embolic coil of any one of claims 8 to 9, wherein the coating includes a hydrophilic polymer having a number average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol.

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