US20230233348A1 - Implantable medical device detachment system with flexible braid section - Google Patents

Abstract

The disclosed technology includes a detachment system for delivering an implantable medical device to a target location of a body vessel including a proximal delivery tube, a distal delivery tube, and a braid segment disposed between. The distal tube includes a proximal end, a distal end, and a compressible portion of the tube itself, between the proximal and distal ends which is axially movable from a compressed to an elongated condition. The proximal tube has a proximal end and a distal end. The braid segment is formed from a plurality of wires. An engagement system engages and deploys the implantable medical device engaged at the distal end of the distal tube.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• The present application is a continuation application of U.S. patent application Ser. No. 16/916,565 filed Jun. 30, 2020. The entire contents of which are hereby incorporated by reference.
FIELD OF INVENTION
• This invention generally relates to interventional medical device systems that are navigable through body vessels of a human subject. More particularly, this invention relates to detachment systems for delivering and deploying an implantable medical device to a target location of a body vessel and methods of using the same.
BACKGROUND
• The use of catheter delivery systems for positioning and deploying therapeutic devices, such as dilation balloons, stents and embolic coils, in the vasculature of the human body has become a standard procedure for treating endovascular diseases. It has been found that such devices are particularly useful in treating areas where traditional operational procedures are impossible or pose a great risk to the patient, for example in the treatment of aneurysms in cranial blood vessels. Due to the delicate tissue surrounding cranial blood vessels, especially for example brain tissue, it is very difficult and often risky to perform surgical procedures to treat defects of the cranial blood vessels. Advancements in catheter deployment systems have provided an alternative treatment in such cases. Some of the advantages of catheter delivery systems are that they provide methods for treating blood vessels by an approach that has been found to reduce the risk of trauma to the surrounding tissue, and they also allow for treatment of blood vessels that in the past would have been considered inoperable.
• Typically, procedures using catheter deployment systems to treat an aneurysm involve inserting the distal end of a delivery catheter into the vasculature of a patient and guiding it through the vasculature to a predetermined delivery site. A vascular occlusion device, such as an embolic coil, can be attached to an implant engagement/delivery system at a distal end of a delivery member (e.g. microcatheter) which pushes the coil through the delivery catheter and out of the distal end of the delivery catheter into the delivery site. Example delivery members and engagement/delivery systems are described in U.S. Patent Publication Number 2019/0192162 A1, U.S. Patent Publication Number 2019/0328398 A1, and U.S. Patent Publication Number 2021/0001082 A1, each of which are incorporated herein by reference.
• Many catheter-based implant delivery systems can include one or more inner elongated member(s) extending through the catheter that can be manipulated at the proximal end by a physician to deploy the implantable device. The inner elongated member can retain the implantable device in the catheter until the time for release of the implant. These systems can be actuated by retracting or pulling the elongated member relative to the catheter. Some of the challenges that have been associated with properly executing such aneurysm treatment procedures include ensuring the delivery member and engagement system remain in a stable position throughout a treatment. For example, in some aneurysm treatment applications, as the aneurysm becomes increasingly packed with embolic material, the delivery member can tend to shift due to increasing pushback from the embolic material being implanted. If the delivery member shifts during treatment, a physician may not be able to accurately control placement of embolic material and may choose to cease packing the aneurysm. In such an example, the aneurysm may not be sufficiently packed, which can lead to recanalization. Further, excessive movement or stretching of the delivery member and/or engagement system thereon can result in premature detachment of the embolic coil. Some examples of ways to mitigate the likelihood of premature release can result in a less flexible mechanical release system.
• Additionally, catheter deployment systems can be used to treat intravascular lesions associated with intracranial atherosclerosis disease (ICAD). In some instances, an intravascular lesion may not be soft enough for a stentriever to effectively engage and remove the lesion from the blood vessel. In such case, it can be desired to deploy a stent such that the intravascular lesion can be treated by stenting. A physician may not know whether the lesion is better treated by a stent or stentriever prior to delivery of either device. Because a stentriever is retractable and a stent typically is not, in such cases, the stentriever is typically deployed in a first pass, followed by the stent (if appropriate) in a second pass. Multiple passes through vasculature can increase trauma to vasculature and increase treatment time, thereby increasing the likelihood of complications.
• Thus, there is a need for systems, devices, and methods that can mitigate the likelihood of premature deployment of an intravascular treatment device while also providing a flexible mechanical release system.
SUMMARY
• Generally, it is an object of the present invention to provide a detachment system for delivering an implantable medical device to a target location of a body vessel that includes a proximal delivery tube, a distal delivery tube, and a braid segment disposed between. The braid segment provides stability during the deployment of the implantable device in the aneurysm, while maximizing flexibility of the detachment system.
• An example detachment system for delivering an implantable medical device to a target location of a blood vessel can include a generally hollow proximal tube, a generally hollow distal tube, a braid segment, and an engagement system. The proximal tube can include a proximal end and a distal end. The distal tube can include a proximal end, a distal end, and a compressible portion of the distal tube itself which is axially moveable from a compressed condition to an elongated condition. The braid segment can be disposed between the proximal end of the distal tube and the distal end of the proximal tube. The braid segment can be formed from a plurality of wires. The engagement system can be configured to engage and deploy the implantable medical device that is disposed at the distal end of the distal tube.
• The braid segment can be concentrically disposed around a polymer liner.
• A polymer sleeve can be positioned over the proximal tube, the braid segment, and at least a portion of the distal tube.
• The polymer sleeve can include one or more hydrophilic coatings.
• The polymer sleeve can have a wall having a thickness of between approximately 0.02 millimeters and approximately 0.08 millimeters.
• The braid segment can include between approximately 8 and approximately 16 wire segments.
• The braid segment can be constructed to have a pick per inch of between approximately 50 and approximately 100.
• The compressible portion of the distal tube can be a spiral-cut portion of the distal tube.
• The engagement system can be configured to move the compressible portion to the compressed condition when engaging the implantable medical device and deploy the implantable medical device when releasing the compressible portion to the elongated condition.
• The compressible portion can be adapted to automatically move to the elongated condition when the engagement system is disengaged from the implantable medical device.
• In one example, the implantable medical device can be a stentriever when engaged to the engagement system, the stentriever having a proximal end collapsed by the engagement system and a distal end collapsed by the engagement system. The implantable medical device can be a stent when disengaged from the engagement system, the stent having an open proximal end and an open distal end.
• An example method of detaching an implantable medical device can include one or more of the following steps presented in no particular order. The method can further include additional steps as appreciated and understood by a person of ordinary skill in the art according to the teachings of this disclosure.
• The method can include forming a compressible portion on a distal tube; forming a flexible portion on a proximal tube; attaching a braid segment to a distal end of a proximal tube and a proximal end of the distal tube; and engaging the implantable medical device with an engagement system.
• The method can further include sliding a polymer sleeve over the proximal tube, the braid segment, and at least a portion of the distal tube.
• The method can further include engaging the polymer sleeve to the implantable medical device.
• The method can further include coating the polymer sleeve with one or more hydrophilic coatings.
• The method can include wrapping the braid segment around a polymer liner prior to attaching the braid segment to the distal end of the proximal tube and the proximal end of the distal tube.
• The engagement step can include using the loop wire with the locking member to engage the implantable medical device and applying force to the loop wire to move the compressible portion to the compressed condition.
• The method can further include applying a force on the locking member, disengaging the implantable medical device, and allowing the compressible portion to return to the elongated condition.
• The method can include deploying the implantable medical device engaged by moving the compressible portion to the elongated condition.
• In one example, the implantable medical device can be a stentriever configured to expand to appose a wall of a blood vessel upon deployment.
BRIEF DESCRIPTION OF DRAWINGS
• The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.
• FIG.1A is an illustration of an example detachment system having a braid segment andFIG.1B is a cross-sectional view of the example detachment system ofFIG.1A, according to aspects of the present invention;
• FIG.2A is an illustration of an additional example detachment system having a braid segment, according to aspects of the present invention;
• FIG.2B is a cross-sectional view of the example detachment system ofFIG.2A, according to aspects of the present invention;
• FIG.3A is an illustration of an additional example detachment system, according to aspects of the present invention;
• FIG.3B is a cross sectional view of the example detachment system ofFIG.3A, according to aspects of the present invention;
• FIG.4A is a side perspective view of an example of a loop wire, according to aspects of the present invention;
• FIG.4B is a plane view of an example of a loop wire according to aspects of the present invention;
• FIG.4C is rear perspective detail view of an opening of the loop wire in an up-turned condition, according to aspects of the present invention;
• FIGS.5A-5D are a series of illustrations of an example implantable medical device being detached, according to aspects of the present invention;
• FIGS.6A-6C are a series of illustrations of deployment of an example stentriever as the implantable medical device, according to aspects of the present invention;
• FIGS.7A-7B are a series of illustrations of an example stentriever being detached, according to aspects of the present invention;
• FIGS.8A-8C are illustrations of an additional example stentriever attached to a deployment system (FIG.8A), in cross-section (FIG.8B), and being detached from the deployment system (FIG.8C), according to aspects of the present invention;
• FIG.9 is a side view of an example of the distal tube in the compressed and expanded state, according to aspects of the present invention; and
• FIG.10 is a flow diagram outlining the steps of detaching an implantable medical device, according to aspects of the present invention.
DETAILED DESCRIPTION
• A key success factor in intravascular treatment such as aneurysm treatments is for the detachment device (e.g. microcatheter) to remain stable during the deployment of an implant or other medical treatment device. During an intravascular treatment, lack of flexibility of a distal portion of a detachment device can cause the detachment device to pull back from the treatment site or otherwise move out of position while the implant is being placed in an aneurysm or other treatment site. A detachment device having a more flexible distal portion can therefore provide a stable system for delivering medical devices in neurovascular anatomy in addition to other applications facing a similar challenge. Flexible structures, however can tend to deform, extend, or expand when navigating tortuous anatomy. Deformation of the detachment system can inhibit the detachment system's ability to navigate to a treatment site and/or effectively deploy the medical device. Elongation of the detachment system can result in premature deployment of the medical device. An object of the present invention is to provide a detachment system having a highly flexible braided segment that is stretch resistant and structurally stable throughout delivery and deployment of a medical treatment device.
• Although example embodiments of the disclosed technology are explained in detail herein, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the disclosed technology be limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The disclosed technology is capable of other embodiments and of being practiced or carried out in various ways.
• It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. By “comprising” or “containing” or “including” it is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.
• In describing example embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It is also to be understood that the mention of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Steps of a method may be performed in a different order than those described herein without departing from the scope of the disclosed technology. Similarly, it is also to be understood that the mention of one or more components in a device or system does not preclude the presence of additional components or intervening components between those components expressly identified.
• As discussed herein, vasculature can be that of any “subject” or “patient” including of any human or animal. It should be appreciated that an animal may be a variety of any applicable type, including, but not limited thereto, mammal, veterinarian animal, livestock animal or pet type animal, etc. As an example, the animal may be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like). It should be appreciated that the subject may be any applicable human patient, for example.
• As discussed herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%.
• The figures illustrate a generally hollow or tubular structure according to the present invention. When used herein, the terms “tubular” and “tube” are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structure or system is generally illustrated as a substantially right cylindrical structure. However, the tubular system may have a tapered or curved outer surface without departing from the scope of the present invention.
• FIGS.1A-3B illustrate examples ofdetachment system10 wherein is disclosed herein and addresses these and other drawbacks of previous approaches. Thedetachment system10 can include aproximal delivery tube100 and adistal delivery tube300. Abraid segment200a,200b,200ccan be disposed between theproximal delivery tube100 and thedistal delivery tube300. Thebraid segment200a,200b,200ccan be formed from a plurality ofwires202. Thebraid segment200bcan be wrapped around apolymer liner204 to minimize friction when delivering thedetachment10 and to protect thebraid segment200b. Apolymer sleeve206 can be disposed over thebraid segment200cto further minimize friction and protect thebraid segment200c. Thebraid segment200a,200b,200callows thedetachment system10 to remain stable during deployment of the implantablemedical device12 while also providing sufficient flexibility that minimizes the potential of thedetachment system10 to move or pull back out of position while the implantable medical device is being positioned in an aneurysm.
• Examples ofdetachment systems10 of the present invention, as illustrated inFIGS.1A through3B can have a proximalelongated delivery tube100, abraid segment200a,200b,200c, and adistal delivery tube300. An implantablemedical device12 can be engaged at thedistal end304 of thedistal delivery tube300. The implantablemedical device12 can be an embolic coil. The implantablemedical device12 can be astent retriever612 as illustrated inFIGS.6A,6B,7A,7B,8A through8C, alternative thereto, or variation thereof. Although the implantablemedical device12 is illustrated as an embolic coil or astent retriever612 herein, it will be appreciated that virtually any implantablemedical device12 may be delivered and deployed by thedetachment system10 according to the present invention. The implantablemedical device12 can be engaged to thedetachment system10 using a lockingmember140 and aloop wire400. The implantablemedical device12 can have a lockingportion18 to interface with anengagement system140,400.
• Theproximal delivery tube100 can have aproximal end portion102, adistal end portion104, and aflexible portion106. Theflexible portion106 can be disposed between theproximal end portion102 and thedistal end portion104. Theproximal delivery tube100 can have an axial lumen therein. Thedistal delivery tube300 can have aproximal end portion302, adistal end portion304, and acompressible portion306. Thecompressible portion306 can be disposed between theproximal end portion302 and thedistal end portion304. Thecompressible portion306 can be closer to thedistal end portion304. Thedistal delivery tube300 can form an axial lumen therein.
• Thedelivery tubes100,300 can be made of a biocompatible material, such as stainless steel. Thedelivery tubes100,300 can have a diameter of between about 0.25 millimeters (0.010 inch) and about 0.46 millimeters (0.018 inch). In one example, the delivery tubes can have a diameter of approximately 0.37 millimeters (0.0145 inch). These examples of tube size are suitable for delivering and deploying embolic coils to target locations, typically aneurysms, within the neurovasculature. It is contemplated that differentlysized delivery tubes100,300 comprised of other materials can be useful for different applications and are within the scope of the present invention.
• Theflexible portion106 of theproximal delivery tube100 can allow theproximal delivery tube100 to bend and flex. This ability can assist tracking thedetachment system10 through the catheter and the tortuous path through the human vasculature. Theflexible portion106 can be formed with interference spiral cuts. These cuts can allow for gaps to permit bending but in one example, do not act as a spiral-cut spring. In this configuration, the interference spiral cuts can bend and flex but do not compress.
• Thecompressible portion306 is axially adjustable between an elongated condition and a compressed condition. Thecompressible portion306 can be formed from a spiral-cut portion of thedistal delivery tube300 by a laser-cutting operation. However, it is contemplated that any other arrangement allowing axial adjustment (e.g., a wound wire or spiral ribbon) is also suitable for use with detachment systems according to the present invention. Thecompressible portion306 can be in the elongated condition at rest and automatically or resiliently return to the elongated condition from a compressed condition, unless otherwise constrained. Thedetachment device10 can include aloop wire400 that together with the lockingmember140 are configured to secure theimplant12 to thedetachment device10. Thecompressible portion306 can be maintained in a compressed condition via tension in theloop wire400 when theloop wire400 and lockingmember140 are engaged to theimplant12. Theloop wire400 can be affixed to thedistal delivery tube300 near theproximal end302 of thedistal delivery tube300.
• Thebraid segment200a,200b,200ccan be disposed between theproximal end302 of thedistal delivery tube300 and thedistal end104 of theproximal delivery tube100. Thebraid segment200a,200b,200ccan be affixed to theproximal end302 of thedistal delivery tube300 and thedistal end104 of theproximal delivery tube100. Thebraid segment200a,200b,200ccan be affixed to theproximal end302 of thedistal delivery tube300 and thedistal end104 of theproximal delivery tube100 using any attachment mechanism including but not limited to, adhesives, welding, or the like. Theproximal delivery tube100 can extend a majority of the length of thedetachment system10, while thebraid segment200a,200b,200cand thedistal delivery tube300 can extend over the most distal portion of the detachment system. In one example, thebraid segment200a,200b,200cand thedistal delivery tube300 can extend over the most distal 500 millimeters of thedetachment system10.
• Thebraid segment200a,200b,200ccan be formed from a plurality ofwires202. The plurality ofwires202 can be made of a biocompatible material, such as stainless steel or nitinol. The plurality ofwires202 can include round wires. Alternatively or in addition to, the plurality ofwires202 can include flat wires. The plurality ofwires202 can include between approximately 6 wires to approximately 20 wires. Thebraid segment200a,200b,200ccan be constructed with various picks per inch. In one example, thebraid segment200a,200b,200ccan be constructed with between approximately 50 picks per inch to approximately 100 picks per inch. The number of wires in the plurality ofwires202 and the picks per inch can result in thebraid segment200a,200b,200chaving a reduced cross-section dimension prior to kinking when a hollow member is bent. By reducing a cross-section dimension, thebraid segment200a,200b,200ccan be substantially oval shaped. The number of wires in the plurality ofwires202 and the picks per inch can facilitate elongation of thebraid segment200a,200b,200csuch that thebraid segment200a,200b,200ccan resist stretching when thedetachment system10 is withdrawn in a blood vessel BV while theimplant12 is held in the aneurysm by friction. Additionally, elongation of thebraid segment200a,200b,200ccan inhibit thebraid segment200a,200b,200cfrom compressing axially or radially collapsing when thecompressible portion106,206,306 is in a compressed configuration prior to deployment.
• When thedetachment device10 is assembled, thebraid segment200a,200b,200ccan be more flexible than theproximal delivery tube100 and thedistal delivery tube300. One way to measure flexibility is to perform a three-point bend test wherein a portion of adetachment system10 is held fixed at two end points, a force is applied perpendicularly to thedetachment system10 centrally between the points, and flexibility is quantified by the length of deflection of thedetachment system10 caused by the force. When measured this way, in some examples, thebraid section200a,200b,200ccan be more flexible than thedistal delivery tube300 and more flexible than theproximal delivery tube100. In other words, when the three-point test is performed identically on the threesections100,200a,200a,200c,300, thebraid segment200a,200b,200ccan deflect over a length that is greater than the deflection length of thedistal delivery tube300 and greater than the length of deflection of theproximal delivery tube100. Flexibility can be measured in other ways as would be appreciated and understood by a person of ordinary skill in the art.
• Theflexible braid segment200a,200b,200ccan be more flexible than the relatively stiffproximal delivery tube100 and the relatively flexibledistal delivery tube300. The relatively stiffproximal delivery tube100 extending a majority of the length of thedetachment system10 can resist kinking while being pushed through a microcatheter. Theflexible braid200a,200b,200cand thedistal delivery tube300 can each be sufficiently flexible to reduce the effects of push-back when the implantablemedical device12 is being placed in an aneurysm. Because theflexible braid segment200a,200b,200cdoes not have to be compressible resilient like the distal tube, theflexible braid segment200a,200b,200ccan have greater flexibility than thedistal delivery tube300. By varying the pick per inch, the number of wire segments, and/or the size of each of the wire segments in the plurality ofwires202, compressibility and elongation of thedetachment system10, including theflexible braid segment200a,200b,200ccan be precisely manipulated and/or controlled.
• As illustrated inFIGS.1A and1B, thebraid segment200acan disposed between theproximal delivery tube100 and thedistal delivery tube300. The lockingmember140 can be disposed within a lumen of thebraid segment200a. The lockingmember140 can be translatable at least in the proximal direction in relation to thedistal end304 of thedistal delivery tube300. The plurality ofwires202 of thebraid segment200acan be exposed. In this configuration, thebraid segment200ais not covered by apolymer sleeve206 or any other protective covering. In this configuration, the plurality ofwires202 can be exposed to the interior walls of blood vessels during delivery of thedetachment system10 to the desired location in the patient.
• FIG.2A illustrates thedetachment system10 having abraid segment200bconcentrically disposed around apolymer liner204. Thepolymer liner204 can be a polytetrafluorothylene (PTFE) liner. Thepolymer liner204 can provide stability to thebraid segment200band reduce friction between thebraid segment200band the lockingmember140 disposed within the lumen of thebraid segment200b. Thebraid segment200bcan be wrapped around thepolymer liner204 prior to thebraid segment200bandpolymer liner204 being attached to theproximal delivery tube100 and thedistal delivery tube300 or thepolymer liner204 can be a separate entity placed inside the entire length of the device including at least a portion of theproximal delivery tube100, at least a portion of thedistal delivery tube300, and at least a portion of thebraid segment200b.
• FIG.2B illustrates a cross-sectional view of thebraid segment200bwrapped around thepolymer liner204. Thepolymer liner204 can have substantially the same shape as theproximal delivery tube100 and thedistal delivery tube300. Thepolymer liner204 can be substantially tubular and can have a lumen disposed therethrough. The lockingmember140 can be slidably disposed within the lumen of thepolymer liner204.
• FIG.3A illustrates thedetachment system10 having abraid segment200csurrounded by apolymer liner204 and apolymer sleeve206 positioned over at least a portion of theproximal delivery tube100, thebraid segment200c, and at least a portion of thedistal delivery tube300. Thepolymer sleeve206 can be slidably disposed over at least a portion of theproximal delivery tube100, thebraid segment200c, and at least a portion of thedistal delivery tube300 after assembly of thedetachment system10. In one example, thepolymer sleeve206 can be positioned over at least a portion of theflexible section106 of theproximal delivery tube100 to inhibit deformation of theflexible section106 and/or reduce friction with vasculature and theflexible section106 during intravascular navigation. In one example, thepolymer sleeve206 can be positioned over the entiredistal delivery tube300 such that thepolymer sleeve206 can be affixed proximate to the implantablemedical device12. In one example, thepolymer sleeve206 can be glued to thedistal delivery tube300 and/orproximal delivery tube100. Alternatively or in addition to, thepolymer sleeve206 can be fused over thebraid segment200csuch that thepolymer sleeve206 can be incorporated into thebraid segment200c. Thepolymer sleeve206 can be affixed to the implantablemedical device12 using an attachment mechanism including adhesives, fusion, welding, or the like. Thepolymer sleeve206 can be a thermoplastic elastomer sleeve. Thepolymer sleeve206 can include one or more additives to increase lubricity so that the sleeve can easily slide through a body vessel.
• Thepolymer sleeve206 can provide stability to thebraid segment200cand reduce friction while delivering thedetachment system10 to the desired location in a patient. Thepolymer sleeve206 can protect thebraid segment200cas thedetachment system10 is transported through the vasculature and to the desired location in a patient.
• FIG.3B illustrates a cross-sectional view of thedetachment system10 illustrated inFIG.3A. Thepolymer sleeve206 can have awall210 with a thickness between approximately 0.02 millimeters to approximately 0.08 millimeters. In one example, one or morehydrophilic coatings208 can be applied to thepolymer sleeve206. The one or morehydrophilic coating208 can include hyaluronic acid, polyalkylene glycols, alkoxy polyalkylene glycols, poly(saccharide), poly(vinylpyrrolidone), poly(vinyl alcohol), poly(acrylic acid), poly(acrylamide), poly(maleicanhydride), copolymers thereof and mixtures thereof. The one or morehydrophilic coating208 can further minimize friction that can occur when delivering thedetachment system10 through the vasculature and to the desired location in a patient.
• As illustrated inFIGS.2A and2B, thebraid segment200ccan include apolymer liner204. Thebraid segment200ccan be concentrically disposed around thepolymer liner204. Thepolymer liner204 can provide stability to thebraid segment200cand reduce friction between thebraid segment200cand the lockingmember140.
• As illustrated inFIG.3B, the lockingmember140 can be translatable through the lumens of theproximal delivery tube100 and thebraid segment200c. The lockingmember140 can further be translatable through the lumen of thedistal delivery tube300, as illustrated inFIG.3A.
• AlthoughFIGS.3A and3B illustrate thedetachment system10 having abraid segment200cconcentrically disposed around apolymer liner204 and apolymer sleeve206 disposed over the at least a portion of theproximal delivery tube100, thebraid segment200c, and at least a portion of thedistal delivery tube300 after assembly of thedetachment system10, it is contemplated that in some instances thebraid segment200cis not disposed around thepolymer liner204.
• FIGS.4A through4C illustrate examples of theloop wire400. Theloop wire400 can be relatively small, having the thickness of a hair in some examples. Because of the small size of theloop wire400, theloop wire400 can be entirely shielded by thedistal end304 of thedistal delivery tube300 to prevent damage from accidental contact. Theloop wire400 can be an elongated wire that is looped to form anopening405, as illustrated inFIG.4A. The loop wire400acan also be a single elongated wire with anopening405a, as illustrated inFIG.4B. Theopening405 can be formed by loosely bending the loop wire400ain half. In an alternative example, theloop wire400bcan include a flat ribbon defining anopening405bat a distal portion and theopening405bcan be in an up-turned condition suitable for engaging an end of the implantablemedical device12 as illustrated inFIG.4C. An example of theloop wire400,400a,400bcan be elastically deformable to the up-turned condition such that it will return to the substantially flat condition when not otherwise constrained. Theloop wire400,400a,400bcan be formed from of any of a number of materials, including nitinol and stainless steel.
• To load thedetachment system10, the lockingmember140 can be inserted axially within the lumens of theproximal delivery tube100, thebraid segment200a,200b,200c, and thedistal delivery tube300. Adistal end404 of theloop wire400 can be inserted into thedistal delivery tube300 through an anchor portion located proximate theproximal end302 of thedistal delivery tube300 as illustrated inFIG.5A. Theloop wire400 can be passed through the lumen of thedistal delivery tube300 to thedistal end304. Thedistal end404 of theloop wire400 can then be looped to form theopening405. Theopening405 can be passed through the lockingportion18 as illustrated inFIG.5A. The lockingmember140 can be passed through theopening405 to engage themedical device12.
• FIGS.5A through5D, illustrate the detachment of the implantablemedical device12 where the implantablemedical device12 is an embolic coil.FIG.5A illustrates thedetachment system10 with the implantablemedical device12 engaged and thecompressible portion306 of the distal as illustrated inFIG.5A tube300 in the compressed state. To reach the compressed state, theloop wire400 can be pulled taught at a proximal end of theloop wire400 and continued force can compress thecompressible portion306. The amount of compression can be controlled by the amount of force applied to the proximal end of theloop wire400 after themedical device12 is mounted to thedistal end304 of thedistal delivery tube300. Once thedistal delivery tube300 is compressed the appropriate amount, theloop wire400 can be anchor welded at a wire weld point proximate theproximal end302 of thedistal delivery tube300 or proximate to the anchor portion of the distal as illustrated inFIG.5A tube300.
• InFIG.5A, the engagement system, including the lockingmember140 and theloop wire400, is locked into the lockingportion18 of themedical device12. Theopening405 of theloop wire400 can be inserted through the lockingportion18. When the lockingmember140 is inserted through theopening405 the implantablemedical device12 can be secured in the desired position.
• FIG.5B illustrates the lockingmember140 being drawn proximally to begin the release sequence for the implantablemedical device12, as indicated by the arrow.
• FIG.5C illustrates the instant the lockingmember140 exits theopening405 and is pulled free of theloop wire400. At this instant, thedistal end404 of theloop wire400 can return to its original, preformed shape and can exit the lockingportion18. Once, the loop wire exits the lockingportion18, no component is holding the implantablemedical device12 to thedetachment system10.
• FIG.5D illustrates the end of the release sequence. Thecompressible portion306 can expand and return to its original, elongated condition. When thecompressible portion306 returns to its original, elongated condition, thecompressible portion306 can “spring” forward. An elastic force E can be imparted by thedistal end304 of thedistal delivery tube300 to the implantablemedical device12 to “push” it away to ensure a clean separation and delivery of themedical device12 to the desired location.
• FIGS.6A through6C illustrate an example treatment method of a thrombus T or lesion within a blood vessel BV using thesame detachment device10 as illustrated inFIGS.1A through3B and astentriever612 as themedical implant12. Thestentriever612 can have aproximal end614 and adistal end616 that can includeloops618. Theproximal end614 of thestentriever612 can be affixed to thedetachment device10. The lockingmember140 can extend through thedistal end616 of thestentriever612, as illustrated inFIG.6A. Thedetachment device10 and thestentriever612 can be disposed within amicrocatheter610 during delivery through the vasculature. Themicrocatheter610 can prevent thestrut framework620 of thestentriever612 from self-expanding. In some instances, themicrocatheter610 can cross a thrombus T or lesion within a blood vessel BV. Themicrocatheter610 can be sized to maintain thestentriever612 collapsed thereon as themicrocatheter610 andstentriever612 are positioned across the thrombus T. The stentriever can be maintained in position as themicrocatheter610 is retracted proximally to allow thestentriever612 to expand to appose the walls of the blood vessel BV.
• FIGS.6B and6C illustrate themicrocatheter610 can be drawn proximally to allow thestrut framework620 of thestentriever612 to begin to expand. Thestrut framework620 can self-expand to appose the walls of the blood vessel BV. Thestentriever612 can includeloops618 disposed at thedistal end616 and theproximal end614. The lockingmember140 extending through thedistal end616 of thestentriever612 can engage with theloops618, such that thedistal end616 and theproximal end614 of thestentriever612 remain closed. By maintaining thedistal end616 and theproximal end614 in a closed configuration via theloops618 engaging with the lockingmember140, when thestentriever612 expands, it can form a substantially conical or tubular shape. Upon expanding, thestrut framework620 can engage and expand through soft material of the thrombus T. Thedetachment device10 affixed to theproximal end614 of thestentriever612 can then be used to facilitate removal of thestentriever612 including the captured thrombus T from the blood vessel BV. Thedetachment device10 and thestentriever612 with the captured thrombus T can be retracted proximally, such that the thrombus T can be effectively removed from the blood vessel BV.
• Upon crossing the affected area including the thrombus T and/or lesion, in some treatments, the thrombus material may be sufficiently soft to pass through thestrut framework620 of the stentriever as illustrated inFIGS.6B and6C. In such cases, thestentriever612 can remain attached to thedetachment device10 as the captured thrombus T,stentriever612, anddetachment device10 are pulled proximally from patient. The removal of thestentriever612 and thrombus T from the patient can be performed with adjunctive aspiration through a larger diameter intermediate catheter positioned over the microcatheter with its tip in close proximity to theproximal end614 of thestentriever612. Alternatively, the thrombus material may not be sufficiently soft to pass through thestrut framework620, or there may be an underlying narrowing (stenosis) of the blood vessel BV after removal of the thrombus T that continues to restrict flow beyond the lesion, in which case the affected area may be better treated by stenting.
• FIGS.7A and7B illustrate an additional treatment method using thedetachment device10 and thestentriever612 that can be applied when stenting is appropriate. As illustrated inFIG.7A, when themicrocatheter610 is drawn proximally, thestentriever612 can begin to expand. As thestentriever612 expands, thestentriever612 can press against the thrombus T, causing the thrombus T to press against the walls of the blood vessel BV. Thedistal end616 and/or theproximal end614 of the stentriever can includeloops618 sized to allow the lockingmember140 to pass through. Theloops618 can be placed at intervals circumferentially around thestentriever612 so that when the lockingmember140 is extended through the loops, thedistal end616 and/or theproximal end614 has a conical shape, extending inward toward the lockingmember140 as illustrated. As the lockingmember140 is drawn proximally, the closeddistal end616 of thestentriever612 can be released, as theloops618 disengaged with the lockingmember140. Once released, thedistal end616 can open such that thedistal end616 can appose the walls of the blood vessel BV. As the lockingmember140 is further drawn proximally, the closedproximal end614 of thestentriever612 can also be released. Theproximal end614 can then open such that theproximal end614 can appose the walls of the blood vessel BV. In this configuration, thestentriever612 is converted into a permanently implantable stent which can continue to press the thrombus T against the blood vessel BV, as well as apply a chronic force against the wall of the blood vessel BV to open any underlying stenosis with or without the aid of a subsequently applied angioplasty balloon dilation.
• As illustrated inFIG.7B, thestentriever612 can be detached from thedetachment device10. Once detached, the “stentriever”612 is no longer retrievable from the body and thereby is, effectively, a stent. The method of detachment of thestentriever612 can be the same detachment method as illustrated inFIGS.5A through5D. Once deployed, the stentriever (stent)612 can remain across the blood vessel BV.
• FIGS.8A through8C illustrate deployment and optional detachment of anadditional example stentriever612 using a similar detachment method anddetachment device10 as illustrated inFIGS.5A through5D. Thestentriever612 can have aproximal end614 and adistal end616. Theproximal end614 can be affixed to thedetachment device10, and more particularly to thedistal end304 of thedistal delivery tube300. When thestentriever612 is affixed to thedetachment device10 prior to deployment, thecompressible portion306 of thedistal delivery tube300 can be in the compressed state.
• As illustrated inFIG.8A, theengagement system140,400 can be engaged with thestentriever612. The lockingmember140 can extend to adistal end616 of thestentriever612 such that the lockingmember140 extends through theopening405 of theloop wire400. Thestentriever612 can includeloops618 similar to as illustrated and described inFIGS.7A and7B. Thestentriever612 can, but need not, include a lockingportion18 having a geometry as illustrated inFIGS.5A and5B. As illustrated inFIG.8A, theloop wire400 can be fed through thestentriever612 near the proximal end of thestentriever612 so that the engagement between theloop wire400, lockingmember140,distal delivery tube300, andstentriever612 are configured to secure the stentriever to thedetachment device10. Thestentriever612 can further includeeyelets622 configured to maintain compression of the body of thestentriever612 during delivery. Theeyelets622 can be shaped similar to theloops618. Theeyelets622 andloops618 can include openings sized to allow the lockingmember140 to pass therethrough. The one ormore eyelets622 can be affixed to theexpandable framework620 and positioned at least partially around the lockingmember140 such that theexpandable framework620 is prevented from pre-maturely deploying and thestentriever612 is securely engaged with theengagement system140,400. In this configuration, theexpandable framework620 can be prevented from expanding even without the use of a catheter. In one example, the one ormore eyelets622 can be disposed along theentire stentriever612. Alternatively, the one or more eyelets can be disposed along a portion of thestentriever612. By way of example, the one ormore eyelets622 can be disposed along a distal portion of thestentriever612.FIG.8B illustrates a cross-sectional view of theexample stentriever612 as illustrated inFIG.8A. Thestentriever612 can be affixed to thedistal delivery tube300, such that thestentriever612 is engaged with thedetachment system10. The lockingmember140 can be translatable through thedistal delivery tube300 and can extend through thestentriever612. Theexpandable framework620 of thestentriever612 can include one ormore eyelets622. As illustrated inFIG.8B, theeyelets622 can be affixed at least partially around the lockingmember140 and to theexpandable framework620 such that thestentriever612 is prevented from expanding pre-maturely.
• FIG.8C illustrates the lockingmember140 can be drawn proximally to begin the release sequence for thestentriever612, as indicated by the arrow. When the lockingmember140 is proximally drawn, theloops618 at thedistal end616 are released, then theeyelets622 are released. As theloops618 andeyelets622 are released, theexpandable framework620 of thestentriever612 can begin to expand. By way of example, as the lockingmember140 is proximally drawn, theeyelets622 disposed proximate the opendistal end616 of thestentriever612 can be first released, such that the opendistal end616stentriever612 can begin to expand. As the lockingmember140 is further proximally drawn, theeyelets622 disposed proximate theproximal end614 of thestentriever612 can be released, such that the openproximal end614 of thestentriever612 can expand.
• At the instant the lockingmember140 exits theopening405 and is pulled free of the loop wire, thedistal end404 of theloop wire400 can return to its original, preformed shape. At this point in the release sequence, no component is holding thestentriever612 to thedetachment system10, as all theeyelets622 affixed to theexpandable framework620 are released.
• After release of thestentriever612, thecompressible portion306 can expand and return to its original, elongated condition as illustrated inFIG.9. When thecompressible portion306 returns to its original, elongated condition, thecompressible portion306 can “spring” forward. An elastic force can be imparted by thedistal end304 of thedistal delivery tube300 to thestentriever612 to “push” it away to ensure a clean separation and delivery of thestentriever612 to the desired location. Upon detachment, thestentriever612 can fully expand such that thestentriever612 can appose the walls of the blood vessel.
• FIG.9 illustrates thedistal delivery tube300 without the implantablemedical device12 in a compressible condition and an elongated condition. Thecompressible portion306 can be shortened in axial length to the compressed condition. Thecompressible portion306 can be shorted in axial length a distance D when moving from the elongated condition to the compressed condition. This compression can occur along the axis A.
• FIG.10 is a flow diagram illustrating amethod1000 of detaching an implantable medical device. The implantable medical device can include adevice12,612 such as illustrated and described herein, a variation thereon, or alternative thereto as understood by a person skilled in the art according to the teachings herein. The method can include one or more of the following steps presented in no particular order. Theexample method1000 can include additional steps as appreciated and understood by a person of ordinary skill in the art. The example method can be performed by anexample detachment system10 as disclosed herein, a variation thereof, or an alternative thereto as appreciated and understood by a person of ordinary skill in the art.
• Instep1005, acompressible portion306 on adistal delivery tube300 can be formed. Thecompressible portion306 on adistal delivery tube300 can be formed by spiral-cutting a portion of thedistal delivery tube300.
• Instep1010, aflexible portion106 on aproximal delivery tube100 can be formed. Theflexible portion106 on theproximal delivery tube100 can be formed by interreference cuts along at least a portion of theproximal delivery tube100.
• In step1015 abraid segment200a,200b,200ccan be attached to adistal end104 of theproximal delivery tube100 and aproximal end302 of thedistal delivery tube300.
• Instep1020, the implantablemedical device12 can be engaged with anengagement system140,400. Theengagement system140,400 can include a lockingmember140 and aloop wire400.
• The method can include using theloop wire400 with the lockingmember140 to engage the implantablemedical device12 and applying force to theloop wire400 to move thecompressible portion306 to the compressed condition.
• The method can include wrapping thebraid segment200baround apolymer liner204 prior to attaching thebraid segment200bto thedistal end104 of theproximal delivery tube100 and the proximal end of thedistal delivery tube300.
• The method can include sliding apolymer sleeve206 over theproximal delivery tube100, thebraid segment200cand at least a portion of thedistal delivery tube300. Thepolymer sleeve206 can be engaged to the implantable medical device.
• The method can include engaging thepolymer sleeve206 to the implantablemedical device12.
• The method can include coating thepolymer sleeve206 with one or morehydrophilic coating208.
• During detachment, the method can include applying a force on the lockingmember140; disengaging the implantablemedical device12; and allowing thecompressible portion306 to return to the elongated condition. By moving thecompressible portion306 to the elongated condition, the implantablemedical device12 can be deployed.
• The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of the inventive delivery and release system for a vascular occlusion device, including numerous configurations, numerous stiffness properties and methods for delivering the same. Also, there are many possible variations in the materials and configurations of the release mechanism. These modifications would be apparent to those having ordinary skill in the art to which this invention relates and are intended to be within the scope of the claims which follow.

Claims (20)

1. A detachment system for delivering an implantable medical device to a target location of a body vessel (BV), comprising:

a generally hollow, relatively stiff proximal tube having a proximal end and a distal end, the distal end comprising a flexible section;

a generally hollow, relatively flexible distal tube comprising:

a proximal end;

a distal end; and

a compressible portion of the relatively flexible distal tube itself which is axially movable from a compressed condition to an elongated condition;

a flexible braid segment disposed between the proximal end of the relatively flexible distal tube and the flexible section of the distal end of the relatively stiff proximal tube, the flexible braid segment formed from a plurality of wires; and

an engagement system configured to engage and deploy the implantable medical device disposed at the distal end of the distal tube,

wherein the flexible braid segment is more flexible than each of the relatively flexible distal tube and the relatively stiff proximal tube.

2. The detachment system ofclaim 1, wherein the flexible braid segment is concentrically disposed around a polymer liner.

3. The detachment system ofclaim 1, wherein a polymer sleeve is positioned over at least a portion of the proximal tube, the braid segment, and at least a portion of the distal tube.

4. The detachment system ofclaim 1, wherein the polymer sleeve includes one or more hydrophilic coatings.

5. The detachment system ofclaim 1, wherein the polymer sleeve has a wall having a thickness of between approximately 0.02 millimeters and approximately 0.08 millimeters.

6. The detachment system ofclaim 1, wherein the flexible braid segment includes between approximately 8 and approximately 16 wires.

7. The detachment system ofclaim 1, wherein the plurality of wires have a pick per inch of between approximately 50 and approximately 100.

8. The detachment system ofclaim 1, wherein the compressible portion of the relatively flexible distal tube is a spiral-cut portion of the relatively flexible distal tube.

9. The detachment system ofclaim 1, wherein the flexible section of the distal end of the relatively stiff proximal tube comprises a spiral-cut portion.

10. The detachment system ofclaim 1, wherein the engagement system is configured to:

move the compressible portion to the compressed condition when engaging the implantable medical device; and

deploy the implantable medical device when releasing the compressible portion to the elongated condition.

11. The detachment system ofclaim 1, wherein the compressible portion is adapted to automatically move to the elongated condition when the engagement system is disengaged from the implantable medical device.

12. A method of detaching an implantable medical device, comprising forming a compressible portion on a proximal end of a relatively flexible distal tube;

forming a flexible portion on a distal end of a relatively stiff proximal tube;

attaching a flexible braid assembly to the distal end of the relatively stiff proximal tube and the proximal end of the relatively flexible distal tube;

sliding a polymer sleeve over at least a portion of the flexible section of the relatively stiff proximal tube, the entirety of the flexible braid assembly, and the entirety of the relatively flexible distal tube; and

engaging the implantable medical device with an engagement system,

wherein the flexible braid segment is more flexible than each of the relatively flexible distal tube and the relatively stiff proximal tube.

13. The detachment method ofclaim 12, wherein a polymer sleeve is positioned over at least a portion of the proximal tube, the braid segment, and at least a portion of the distal tube.

14. The detachment method ofclaim 13, further comprising engaging the polymer sleeve to the implantable medical device.

15. The detachment method ofclaim 13, further comprising coating the polymer sleeve with one or more hydrophilic coatings.

16. The detachment method ofclaim 12, further comprising wrapping the flexible braid assembly around a polymer liner prior to attaching the flexible braid assembly to the distal end of the relatively stiff proximal tube and the proximal end of the relatively flexible distal tube.

17. The detachment method ofclaim 12, wherein the engagement system comprises a locking member, and a loop wire,

wherein engaging the implantable medical device with the engagement system further comprises using the loop wire with the locking member to engage the implantable medical device; and

wherein the applying step further comprises applying force to the loop wire to move the compressible portion to a compressed condition.

18. The detachment method ofclaim 17, further comprising:

applying a force on the locking member;

disengaging the implantable medical device; and

allowing the compressible portion to return to an elongated condition.

19. The detachment method ofclaim 12, wherein forming the compressible portion on the relatively flexible distal tube includes spiral-cutting a portion of the relatively flexible distal tube.

20. The detachment method ofclaim 12, further comprising deploying the implantable medical device by moving the compressible portion to an elongated condition.

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