Patent Application
20220192678
Not applicable.
Embodiments of devices and methods herein are directed to blocking a flow of fluid through a tubular vessel or into a small interior chamber of a saccular cavity or vascular defect within a mammalian body. More specifically, embodiments herein are directed to devices and methods for treatment of a vascular defect of a patient including some embodiments directed specifically to the treatment of cerebral aneurysms of patients.
The mammalian circulatory system is comprised of a heart, which acts as a pump, and a system of blood vessels which transport the blood to various points in the body. Due to the force exerted by the flowing blood on the blood vessel the blood vessels may develop a variety of vascular defects. One common vascular defect known as an aneurysm results from the abnormal widening of the blood vessel. Typically, vascular aneurysms are formed as a result of the weakening of the wall of a blood vessel and subsequent ballooning and expansion of the vessel wall. If, for example, an aneurysm is present within an artery of the brain, and the aneurysm should burst with resulting cranial hemorrhaging, death could occur.
Surgical techniques for the treatment of cerebral aneurysms typically involve a craniotomy requiring creation of an opening in the skull of the patient through which the surgeon can insert instruments to operate directly on the patient's brain. For some surgical approaches, the brain must be retracted to expose the parent blood vessel from which the aneurysm arises. Once access to the aneurysm is gained, the surgeon places a clip across the neck of the aneurysm thereby preventing arterial blood from entering the aneurysm. Upon correct placement of the clip the aneurysm will be obliterated in a matter of minutes. Surgical techniques may be effective treatment for many aneurysms. Unfortunately, surgical techniques for treating these types of conditions include major invasive surgical procedures which often require extended periods of time under anesthesia involving high risk to the patient. Such procedures thus require that the patient be in generally good physical condition in order to be a candidate for such procedures.
Various alternative and less invasive procedures have been used to treat cerebral aneurysms without resorting to major surgery. One approach to treating aneurysms without the need for invasive surgery involves the placement of sleeves or stents into the vessel and across the region where the aneurysm occurs. Such devices maintain blood flow through the vessel while reducing blood pressure applied to the interior of the aneurysm. Certain types of stents are expanded to the proper size by inflating a balloon catheter, referred to as balloon expandable stents, while other stents are designed to elastically expand in a self-expanding manner. Some stents are covered typically with a sleeve of polymeric material called a graft to form a stent-graft. Stents and stent-grafts are generally delivered to a preselected position adjacent a vascular defect through a delivery catheter. In the treatment of cerebral aneurysms, covered stents or stent-grafts have seen very limited use due to the likelihood of inadvertent occlusion of small perforator vessels that may be near the vascular defect being treated.
In addition, current uncovered stents are generally not sufficient as a stand-alone treatment. In order for stents to fit through the microcatheters used in small cerebral blood vessels, their density is usually reduced such that when expanded there is only a small amount of stent structure bridging the aneurysm neck. Thus, they do not block enough flow to cause clotting of the blood in the aneurysm and are thus generally used in combination with vaso-occlusive devices, such as the coils discussed above, to achieve aneurysm occlusion.
Some procedures involve the delivery of embolic or filling materials into an aneurysm. The delivery of such vaso-occlusion devices or materials may be used to promote hemostasis or fill an aneurysm cavity entirely. Vaso-occlusion devices may be placed within the vasculature of the human body, typically via a catheter, either to block the flow of blood through a vessel with an aneurysm through the formation of an embolus or to form such an embolus within an aneurysm stemming from the vessel. A variety of implantable, coil-type vaso-occlusion devices are known. The coils of such devices may themselves be formed into a secondary coil shape, or any of a variety of more complex secondary shapes. Vaso-occlusive coils are commonly used to treat cerebral aneurysms but suffer from several limitations including poor packing density, compaction due to hydrodynamic pressure from blood flow, poor stability in wide-necked aneurysms, and complexity and difficulty in the deployment thereof as most aneurysm treatments with this approach require the deployment of multiple coils. Coiling is less effective at treating certain physiological conditions, such as wide neck cavities (e.g. wide neck aneurysms) because there is a greater risk of the coils migrating out of the treatment site.
A number of aneurysm neck bridging devices with defect spanning portions or regions have been attempted, however, none of these devices have had a significant measure of clinical success or usage. A major limitation in their adoption and clinical usefulness is the inability to position the defect spanning portion to assure coverage of the neck. Existing stent delivery systems that are neurovascular compatible (i.e. deliverable through a microcatheter and highly flexible) do not have the necessary rotational positioning capability. Another limitation of many aneurysm bridging devices described in the prior art is the poor flexibility. Cerebral blood vessels are tortuous, and a high degree of flexibility is required for effective delivery to most aneurysm locations in the brain.
What has been needed are devices and methods for delivery and use in small and tortuous blood vessels that can substantially block the flow of blood into an aneurysm, such as a cerebral aneurysm, with a decreased risk of inadvertent aneurysm rupture or blood vessel wall damage. In addition, what has been needed are methods and devices suitable for blocking blood flow in cerebral aneurysms over an extended period of time without a significant risk of deformation, compaction or dislocation.
Intrasaccular occlusive devices are part of a newer type of occlusion device used to treat various intravascular conditions including aneurysms. They are often more effective at treating these wide neck conditions, or larger treatment areas. The intrasaccular devices comprise a structure which sits within the aneurysm and provides an occlusive effect at the neck of the aneurysm to help limit blood flow into the aneurysm. The rest of the device comprises a relatively conformable structure that sits within the aneurysm helping to occlude all or a portion of the aneurysm. Intrasaccular devices typically conform to the shape of the treatment site. These devices also occlude the cross section of the neck of the treatment site/aneurysm, thereby promoting clotting and causing thrombosis and closing of the aneurysm over time. In larger aneurysms, there is a risk of compaction where the intrasaccular device can migrate into the aneurysm and leave the neck region.
Occlusive devices are used for a variety of reasons within the vascular system, such as to limit blood flow to aneurysms to reduce risk of rupture. Other reasons include vessel shutdown and occluding various structures such as arteriovenous malformations, fistula, left atrial appendage, fallopian tubes. One class of occlusive devices are known as intrasaccular devices and are used in treating aneurysms. Aneurysms are typically occluded with small embolic coils that fill the space of the aneurysm, typically a number of coils are used in the procedure to sufficiently occlude or fill the target space. The procedure typically also includes a balloon or stent placed adjacent the aneurysm location to reduce the risk of coils falling out of the aneurysm and migrating elsewhere. Even with these additional devices in use, there is still a risk of the coils sticking out of the aneurysm.
Aneurysms that are only treated with flow diverters can clot and heal “naturally” because no material is placed inside the aneurysm sac. This natural healing response may consist of clotting, axial and/or radial aneurysm contraction (e g , “shrinkage”) and eventual dissolution of the aneurysm wall. Intralumenal flow diverters, however, generally have higher rates of morbidity and mortality compared to intrasaccular therapies such as embolic coils and WEB implants.
Occlusive and coil devices, conversely, have relatively low rates of morbidity and mortality and are often much more easily placed in situ than flow diverters. The presence of material within the aneurysm sac, however, may interfere with the natural healing response of the aneurysm. Aneurysms that are embolized with intrasaccular occlusive implants can contract to some degree, at least axially. Aneurysms embolized with coils are thought to allow for less aneurysm contraction due to the density of coils needed to obtain stasis.
Thus, there is a need for occlusive devices that contract or reduce in size over time, which allows for the aneurysm to heal “naturally” and shrink or contract (either axial and/or radial contraction).
The following embodiments address this issue by utilizing concepts to promote healing and shrinkage or contraction of the aneurysm through treatment with implants that reduce in size over time.
An occlusion device is described that is used to treat a variety of conditions, including aneurysms and neurovascular aneurysms, in particular, bifurcation aneurysms. In some embodiments, the occlusion device is configured as an intrasaccular device.
In many embodiments, a device for treatment of a patient's cerebral aneurysm is described. The device includes an expandable frame having a proximal end, a distal end, a middle region between the proximal and distal ends, a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate biodegradable filaments that extend from the proximal end to the distal end; and a permeable shell having a radially constrained elongated state configured for delivery within the catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh, wherein in the expanded state, the permeable shell extends from the proximal end of the expandable frame to the middle region of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is smaller than a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is about half a length of the expanded state of the expandable frame. In some embodiments, a length of the expanded state of the permeable shell is between about ¼ and about ¾ of a length of the expanded state of the expandable frame. In some embodiments, a length of the expanded state of the permeable shell is between about ⅓ and about ⅔ of a length of the expanded state of the expandable frame. In some embodiments, a length of the expanded state of the permeable shell is less than approximately 60% of a length of the expanded state of the expandable frame.
In some embodiments, an inner surface of second permeable shell is in contact with an outer surface of the expandable frame.
In some embodiments, a diameter of the expanded state of the permeable shell in a proximal region is larger than a diameter of the expanded state of the expandable frame in a proximal region.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the proximal ends of each of the plurality of filaments of the permeable shell and the proximal ends of the plurality of elongate biodegradable filaments are gathered in a hub. In some embodiments, the hub is radiopaque.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the distal ends of each of the plurality of filaments of the permeable shell are not gathered in a hub.
In some embodiments, the permeable shell has an open distal end. In some embodiments, the expanded state of the permeable shell has a recessed proximal end.
In some embodiments, a proximal end of the expanded state of the permeable shell has a concave portion.
In some embodiments, a proximal end of the expanded state of the permeable shell has a substantially flat portion. In some embodiments, the substantially flat portion comprises a concave portion that includes a hub.
In some embodiments, the expanded state, a proximal region of the permeable shell does not contact a proximal region of the expandable frame.
In some embodiments, in the expanded state, a height of a portion of the permeable shell that does not contact the expandable frame is between about 20% to about 90% of a total height of the permeable shell.
In many embodiments, a method for treating a cerebral aneurysm having an interior cavity and a neck is described. The method includes the steps of advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises: an expandable frame having a proximal end, a distal end, a middle region between the proximal and distal ends, a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate biodegradable filaments that extend from the proximal end to the distal end; and a permeable shell having a radially constrained elongated state configured for delivery within the catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh, wherein in the expanded state, the permeable shell extends from the proximal end of the expandable frame to the middle region of the expandable frame; deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and withdrawing the microcatheter from the region of interest after deploying the implant.
In some embodiments, the implant is advanced through a lumen of the microcatheter by advancing a pusher the is detachably coupled to a distal end of the implant, further comprising the step of detaching the implant from the pusher. In some embodiments, the implant is detachably coupled to the distal end of the pusher through a thermal, mechanical, or electrolytic mechanism.
In some embodiments, a length of the expanded state of the permeable shell is smaller than a length of the expanded state of the expandable frame. In some embodiments, a length of the expanded state of the permeable shell is about half a length of the expanded state of the expandable frame. In some embodiments, a length of the expanded state of the permeable shell is less than approximately 60% of a length of the expanded state of the expandable frame.
In some embodiments, an inner surface of second permeable shell is in contact with an outer surface of the expandable frame.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the proximal ends of each of the plurality of filaments of the permeable shell and the proximal ends of the plurality of elongate biodegradable filaments are gathered in a hub.
In some embodiments, a proximal end of the expanded state of the permeable shell has a substantially flat portion. In some embodiments, the substantially flat portion comprises a concave portion that includes a hub.
In some embodiments, the expanded state, a proximal region of the permeable shell does not contact a proximal region of the expandable frame.
In some embodiments, in the expanded state, a height of a portion of the permeable shell that does not contact the expandable frame is between about 20% to about 90% of a total height of the permeable shell.
In many embodiments, a device for treatment of a patient's cerebral aneurysm is described. The device includes a first permeable shell formed from a first plurality of elongate filaments that are woven together to form a mesh, the first permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within a catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a proximal end of each of the plurality of elongate filaments are gathered at the proximal end of the first permeable shell, and wherein the expanded state has an open distal end; and a second permeable shell formed from a second plurality of elongate filaments that are woven together to form a mesh, the second permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within the catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a distal end of each of the second plurality of elongate filaments are gathered at the distal end of the second permeable shell, and wherein the expanded state has an open proximal end, and wherein the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together.
In some embodiments, the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together with a biodegradable filament. In some embodiments, the biodegradable filament comprises PGLA.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first length and the open distal end of the expanded state of the second permeable shell has a second length, and wherein the second length is smaller than the first length. In some embodiments, the first length is a first diameter and the second length is a second diameter.
In some embodiments, a height of the first permeable shell is about equal to a height of the second permeable shell. In some embodiments, a height of the first permeable shell is longer than a height of the second permeable shell.
In some embodiments, the first permeable shell comprises an inner cavity, wherein the second permeable shell is configured to at least partially fit within the inner cavity.
In some embodiments, the open distal end of the first permeable shell has a substantially circular shape. In some embodiments, the open proximal end of the second permeable shell has a substantially circular shape.
In some embodiments, at least a portion of the first permeable shell has a convex outer surface. In some embodiments, at least a portion of the second permeable shell has a convex outer surface. In some embodiments, the proximal end of the first permeable shell has a recessed portion. In some embodiments, the distal end of the second permeable shell has a recessed portion.
In many embodiments, a method for treating a cerebral aneurysm having an interior cavity and a neck is described. The method includes the steps of advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises: a first permeable shell formed from a first plurality of elongate filaments that are woven together to form a mesh, the first permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within a catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a proximal end of each of the plurality of elongate filaments are gathered at the proximal end of the first permeable shell, and wherein the expanded state has an open distal end; and a second permeable shell formed from a second plurality of elongate filaments that are woven together to form a mesh, the second permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within the catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a distal end of each of the second plurality of elongate filaments are gathered at the distal end of the second permeable shell, and wherein the expanded state has an open proximal end, and wherein the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together; deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and withdrawing the microcatheter from the region of interest after deploying the implant.
In some embodiments, the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together with a biodegradable filament. In some embodiments,
In some embodiments, the biodegradable filament comprises PGLA.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first length and the open distal end of the expanded state of the second permeable shell has a second length, and wherein the second length is smaller than the first length. In some embodiments, the first length is a first diameter and the second length is a second diameter.
In some embodiments, a height of the first permeable shell is about equal to a height of the second permeable shell. In some embodiments, a height of the first permeable shell is longer than a height of the second permeable shell.
In some embodiments, the first permeable shell comprises an inner cavity, wherein the second permeable shell is configured to at least partially fit within the inner cavity.
In some embodiments, the open distal end of the first permeable shell has a substantially circular shape, and wherein the open proximal end of the second permeable shell has a substantially circular shape.
In some embodiments, at least a portion of the first permeable shell has a convex outer surface, and wherein at least a portion of the second permeable shell has a convex outer surface.
In some embodiments, the proximal end of the first permeable shell has a recessed portion. In some embodiments, the distal end of the second permeable shell has a recessed portion.
In some embodiments, the distal permeable shell moves proximally such that at least a portion of the distal permeable shell resides in an inner cavity of the proximal permeable shell after the biodegradable filament degrades.
Discussed herein are devices and methods for the treatment of vascular defects that are suitable for minimally invasive deployment within a patient's vasculature, and particularly, within the cerebral vasculature of a patient. For such embodiments to be safely and effectively delivered to a desired treatment site and effectively deployed, some device embodiments may be configured for collapse to a low profile constrained state with a transverse dimension suitable for delivery through an inner lumen of a microcatheter and deployment from a distal end thereof. Embodiments of these devices may also maintain a clinically effective configuration with sufficient mechanical integrity once deployed so as to withstand dynamic forces within a patient's vasculature over time that may otherwise result in compaction of a deployed device. It may also be desirable for some device embodiments to acutely occlude a vascular defect of a patient during the course of a procedure in order to provide more immediate feedback regarding success of the treatment to a treating physician.
Intrasaccular occlusive devices that include a permeable shell formed from a woven or braided mesh have been described in US 2017/0095254, US 2016/0249934, US 2016/0367260, US 2016/0249937, and US 2018/0000489, all of which are hereby expressly incorporated by reference in their entirety for all purposes.
Some embodiments are particularly useful for the treatment of cerebral aneurysms by reconstructing a vascular wall so as to wholly or partially isolate a vascular defect from a patient's blood flow. Some embodiments may be configured to be deployed within a vascular defect to facilitate reconstruction, bridging of a vessel wall or both in order to treat the vascular defect. For some of these embodiments, the permeable shell of the device may be configured to anchor or fix the permeable shell in a clinically beneficial position. For some embodiments, the device may be disposed in whole or in part within the vascular defect in order to anchor or fix the device with respect to the vascular structure or defect. The permeable shell may be configured to span an opening, neck or other portion of a vascular defect in order to isolate the vascular defect, or a portion thereof, from the patient's nominal vascular system in order allow the defect to heal or to otherwise minimize the risk of the defect to the patient's health.
For some or all of the embodiments of devices for treatment of a patient's vasculature discussed herein, the permeable shell may be configured to allow some initial perfusion of blood through the permeable shell. The porosity of the permeable shell may be configured to sufficiently isolate the vascular defect so as to promote healing and isolation of the defect, but allow sufficient initial flow through the permeable shell so as to reduce or otherwise minimize the mechanical force exerted on the membrane the dynamic flow of blood or other fluids within the vasculature against the device. For some embodiments of devices for treatment of a patient's vasculature, only a portion of the permeable shell that spans the opening or neck of the vascular defect, sometimes referred to as a defect spanning portion, need be permeable and/or conducive to thrombus formation in a patient's bloodstream. For such embodiments, that portion of the device that does not span an opening or neck of the vascular defect may be substantially non-permeable or completely permeable with a pore or opening configuration that is too large to effectively promote thrombus formation.
In general, it may be desirable in some cases to use a hollow, thin walled device with a permeable shell of resilient material that may be constrained to a low profile for delivery within a patient. Such a device may also be configured to expand radially outward upon removal of the constraint such that the shell of the device assumes a larger volume and fills or otherwise occludes a vascular defect within which it is deployed. The outward radial expansion of the shell may serve to engage some or all of an inner surface of the vascular defect whereby mechanical friction between an outer surface of the permeable shell of the device and the inside surface of the vascular defect effectively anchors the device within the vascular defect. Some embodiments of such a device may also be partially or wholly mechanically captured within a cavity of a vascular defect, particularly where the defect has a narrow neck portion with a larger interior volume. In order to achieve a low profile and volume for delivery and be capable of a high ratio of expansion by volume, some device embodiments include a matrix of woven or braided filaments that are coupled together by the interwoven structure so as to form a self-expanding permeable shell having a pore or opening pattern between couplings or intersections of the filaments that is substantially regularly spaced and stable, while still allowing for conformity and volumetric constraint.
As used herein, the terms woven and braided are used interchangeably to mean any form of interlacing of filaments to form a mesh structure. In the textile and other industries, these terms may have different or more specific meanings depending on the product or application such as whether an article is made in a sheet or cylindrical form. For purposes of the present disclosure, these terms are used interchangeably.
For some embodiments, three factors may be critical for a woven or braided wire occlusion device for treatment of a patient's vasculature that can achieve a desired clinical outcome in the endovascular treatment of cerebral aneurysms. We have found that for effective use in some applications, it may be desirable for the implant device to have sufficient radial stiffness for stability, limited pore size for near-complete acute (intra-procedural) occlusion and a collapsed profile which is small enough to allow insertion through an inner lumen of a microcatheter. A device with a radial stiffness below a certain threshold may be unstable and may be at higher risk of embolization in some cases. Larger pores between filament intersections in a braided or woven structure may not generate thrombus and occlude a vascular defect in an acute setting and thus may not give a treating physician or health professional such clinical feedback that the flow disruption will lead to a complete and lasting occlusion of the vascular defect being treated. Delivery of a device for treatment of a patient's vasculature through a standard microcatheter may be highly desirable to allow access through the tortuous cerebral vasculature in the manner that a treating physician is accustomed. A detailed discussion of radial stiffness, pore size, and the necessary collapsed profile can be found in US 2017/0095254, which was previously expressly incorporated by reference in its entirety.
As has been discussed, some embodiments of devices for treatment of a patient's vasculature call for sizing the device which approximates (or with some over-sizing) the vascular site dimensions to fill the vascular site. One might assume that scaling of a device to larger dimensions and using larger filaments would suffice for such larger embodiments of a device. However, for the treatment of brain aneurysms, the diameter or profile of the radially collapsed device is limited by the catheter sizes that can be effectively navigated within the small, tortuous vessels of the brain. Further, as a device is made larger with a given or fixed number of resilient filaments having a given size or thickness, the pores or openings between junctions of the filaments are correspondingly larger. In addition, for a given filament size the flexural modulus or stiffness of the filaments and thus the structure decrease with increasing device dimension. Flexural modulus may be defined as the ratio of stress to strain. Thus, a device may be considered to have a high flexural modulus or be stiff if the strain (deflection) is low under a given force. A stiff device may also be said to have low compliance.
To properly configure larger size devices for treatment of a patient's vasculature, it may be useful to model the force on a device when the device is deployed into a vascular site or defect, such as a blood vessel or aneurysm, that has a diameter or transverse dimension that is smaller than a nominal diameter or transverse dimension of the device in a relaxed unconstrained state. As discussed, it may be advisable to “over-size” the device in some cases so that there is a residual force between an outside surface of the device and an inside surface of the vascular wall. The inward radial force on a device 10 that results from over-sizing is illustrated schematically in
Deflection of Beam=5FL4/384 El
Thus, as the size of the device increases and L increases, the compliance increases substantially. Accordingly, an outward radial force exerted by an outside surface of the filaments 14 of the device 10 against a constraining force when inserted into a vascular site such as blood vessel or aneurysm is lower for a given amount of device compression or over-sizing. This force may be important in some applications to assure device stability and to reduce the risk of migration of the device and potential distal embolization.
In some embodiments, a combination of small and large filament sizes may be utilized to make a device with a desired radial compliance and yet have a collapsed profile which is configured to fit through an inner lumen of commonly used microcatheters. A device fabricated with even a small number of relatively large filaments 14 can provide reduced radial compliance (or increased stiffness) compared to a device made with all small filaments. Even a relatively small number of larger filaments may provide a substantial increase in bending stiffness due to change in the moment of Inertia that results from an increase in diameter without increasing the total cross sectional area of the filaments. The moment of inertia (I) of a round wire or filament may be defined by the equation:
I=πd
4/64
Since the moment of inertia is a function of filament diameter to the fourth power, a small change in the diameter greatly increases the moment of inertia. Thus, small changes in filament size can have substantial impact on the deflection at a given load and thus the compliance of the device.
Thus, the stiffness can be increased by a significant amount without a large increase in the cross sectional area of a collapsed profile of the device 10. This may be particularly important as device embodiments are made larger to treat large aneurysms. While large cerebral aneurysms may be relatively rare, they present an important therapeutic challenge as some embolic devices currently available to physicians have relatively poor results compared to smaller aneurysms.
As such, some embodiments of devices for treatment of a patient's vasculature may be formed using a combination of filaments 14 with a number of different diameters such as 2, 3, 4, 5 or more different diameters or transverse dimensions. In device embodiments where filaments with two different diameters are used, some larger filament embodiments may have a transverse dimension of about 0.001 inches to about 0.004 inches and some small filament embodiments may have a transverse dimension or diameter of about 0.0004 inches and about 0.0015 inches, more specifically, about 0.0004 inches to about 0.001 inches. The ratio of the number of large filaments to the number of small filaments may be between about 2 and 12 and may also be between about 4 and 8. In some embodiments, the difference in diameter or transverse dimension between the larger and smaller filaments may be less than about 0.004 inches, more specifically, less than about 0.0035 inches, and even more specifically, less than about 0.002 inches.
As discussed above, device embodiments 10 for treatment of a patient's vasculature may include a plurality of wires, fibers, threads, tubes or other filamentary elements that form a structure that serves as a permeable shell. For some embodiments, a globular shape may be formed from such filaments by connecting or securing the ends of a tubular braided structure. For such embodiments, the density of a braided or woven structure may inherently increase at or near the ends where the wires or filaments 14 are brought together and decrease at or near a middle portion 30 disposed between a proximal end 32 and distal end 34 of the permeable shell 40. For some embodiments, an end or any other suitable portion of a permeable shell 40 may be positioned in an opening or neck of a vascular defect such as an aneurysm for treatment. As such, a braided or woven filamentary device with a permeable shell may not require the addition of a separate defect spanning structure having properties different from that of a nominal portion of the permeable shell to achieve hemostasis and occlusion of the vascular defect. Such a filamentary device may be fabricated by braiding, weaving or other suitable filament fabrication techniques. Such device embodiments may be shape set into a variety of three-dimensional shapes such as discussed herein.
Referring to
As shown in
As such, once the device 10 is deployed, any blood flowing through the permeable shell may be slowed to a velocity below the thrombotic threshold velocity and thrombus will begin to form on and around the openings in the permeable shell 40. Ultimately, this process may be configured to produce acute occlusion of the vascular defect within which the device 10 is deployed. For some embodiments, at least the distal end of the permeable shell 40 may have a reverse bend in an everted configuration such that the secured distal ends 62 of the filaments 14 are withdrawn axially within the nominal permeable shell structure or contour in the expanded state. For some embodiments, the proximal end of the permeable shell further includes a reverse bend in an everted configuration such that the secured proximal ends 60 of the filaments 14 are withdrawn axially within the nominal permeable shell structure 40 in the expanded state. As used herein, the term everted may include a structure that is everted, partially everted and/or recessed with a reverse bend as shown in the device embodiment of
The elongate resilient filaments 14 of the permeable shell 40 may be secured relative to each other at proximal ends 60 and distal ends 62 thereof by one or more methods including welding, soldering, adhesive bonding, epoxy bonding or the like. In addition to the ends of the filaments being secured together, a distal hub 66 may also be secured to the distal ends 62 of the thin filaments 14 of the permeable shell 40 and a proximal hub 68 secured to the proximal ends 60 of the thin filaments 14 of the permeable shell 40. The proximal hub 68 may include a cylindrical member that extends proximally beyond the proximal ends 60 of the thin filaments so as to form a cavity 70 within a proximal portion of the proximal hub 68. The proximal cavity 70 may be used for holding adhesives such as epoxy, solder or any other suitable bonding agent for securing an elongate detachment tether 72 that may in turn be detachably secured to a delivery apparatus such as is shown in
For some embodiments, the elongate resilient filaments 14 of the permeable shell 40 may have a transverse cross section that is substantially round in shape and be made from a superelastic material that may also be a shape memory metal. The shape memory metal of the filaments of the permeable shell 40 may be heat set in the globular configuration of the relaxed expanded state as shown in
The device 10 may have an everted filamentary structure with a permeable shell 40 having a proximal end 32 and a distal end 34 in an expanded relaxed state. The permeable shell 40 has a substantially enclosed configuration for the embodiments shown. Some or all of the permeable shell 40 of the device 10 may be configured to substantially block or impede fluid flow or pressure into a vascular defect or otherwise isolate the vascular defect over some period of time after the device is deployed in an expanded state. The permeable shell 40 and device 10 generally also has a low profile, radially constrained state, as shown in
Proximal ends 60 of at least some of the filaments 14 of the permeable shell 40 may be secured to the proximal hub 68 and distal ends 62 of at least some of the filaments 14 of the permeable shell 40 are secured to the distal hub 66, with the proximal hub 68 and distal hub 66 being disposed substantially concentric to the longitudinal axis 46 as shown in
Some device embodiments 10 having a braided or woven filamentary structure may be formed using about 10 filaments to about 300 filaments 14, more specifically, about 10 filaments to about 100 filaments 14, and even more specifically, about 60 filaments to about 80 filaments 14. Some embodiments of a permeable shell 40 may include about 70 filaments to about 300 filaments extending from the proximal end 32 to the distal end 34, more specifically, about 100 filaments to about 200 filaments extending from the proximal end 32 to the distal end 34. For some embodiments, the filaments 14 may have a transverse dimension or diameter of about 0.0008 inches to about 0.004 inches. The elongate resilient filaments 14 in some cases may have an outer transverse dimension or diameter of about 0.0005 inch to about 0.005 inch, more specifically, about 0.001 inch to about 0.003 inch, and in some cases about 0.0004 inches to about 0.002 inches. For some device embodiments 10 that include filaments 14 of different sizes, the large filaments 48 of the permeable shell 40 may have a transverse dimension or diameter that is about 0.001 inches to about 0.004 inches and the small filaments 50 may have a transverse dimension or diameter of about 0.0004 inches to about 0.0015 inches, more specifically, about 0.0004 inches to about 0.001 inches. In addition, a difference in transverse dimension or diameter between the small filaments 50 and the large filaments 48 may be less than about 0.004 inches, more specifically, less than about 0.0035 inches, and even more specifically, less than about 0.002 inches. For embodiments of permeable shells 40 that include filaments 14 of different sizes, the number of small filaments 50 of the permeable shell 40 relative to the number of large filaments 48 of the permeable shell 40 may be about 2 to 1 to about 15 to 1, more specifically, about 2 to 1 to about 12 to 1, and even more specifically, about 4 to 1 to about 8 to 1.
The expanded relaxed state of the permeable shell 40, as shown in
For some embodiments, the permeable shell 40 may have a first transverse dimension in a collapsed radially constrained state of about 0.2 mm to about 2 mm and a second transverse dimension in a relaxed expanded state of about 4 mm to about 30 mm. For some embodiments, the second transverse dimension of the permeable shell 40 in an expanded state may be about 2 times to about 150 times the first transverse dimension, more specifically, about 10 times to about 25 times the first or constrained transverse dimension. A longitudinal spacing between the proximal end 32 and distal end 34 of the permeable shell 40 in the relaxed expanded state may be about 25% percent to about 75% percent of the spacing between the proximal end 32 and distal end 34 in the constrained cylindrical state. For some embodiments, a major transverse dimension of the permeable shell 40 in a relaxed expanded state may be about 4 mm to about 30 mm, more specifically, about 9 mm to about 15 mm, and even more specifically, about 4 mm to about 8 mm.
An arced portion of the filaments 14 of the permeable shell 40 may have a sinusoidal-like shape with a first or outer radius 88 and a second or inner radius 90 near the ends of the permeable shell 40 as shown in
The first radius 88 and second radius 90 of the permeable shell 40 may be between about 0.12 mm to about 3 mm for some embodiments. For some embodiments, the distance between the proximal end 32 and distal end 34 may be more than about 60% of the overall length of the expanded permeable shell 40. Thus, the largest longitudinal distance between the inner surfaces may be about 60% to about 90% of the longitudinal length of the outer surfaces or the overall length of device 10. A gap between the hubs 66 and 68 at the proximal end 32 and distal end 34 may allow for the distal hub 66 to flex downward toward the proximal hub 68 when the device 10 meets resistance at the distal end and thus provides longitudinal conformance. The filaments 14 may be shaped such that there are no portions that are without curvature over a distance of more than about 2 mm. Thus, for some embodiments, each filament 14 may have a substantially continuous curvature. This substantially continuous curvature may provide smooth deployment and may reduce the risk of vessel perforation. The distal end 34 may be retracted or everted to a greater extent than the proximal end 32 such that the distal end portion of the permeable shell 40 may be more radially conformal than the proximal end portion. Conformability of a distal end portion may provide better device conformance to irregular shaped aneurysms or other vascular defects. A convex surface of the device may flex inward forming a concave surface to conform to curvature of a vascular site.
The pore size defined by the largest circular shapes 100 that may be disposed within openings 64 of the braided structure of the permeable shell 40 without displacing or distorting the filaments 14 surrounding the opening 64 may range in size from about 0.005 inches to about 0.01 inches, more specifically, about 0.006 inches to about 0.009 inches, even more specifically, about 0.007 inches to about 0.008 inches for some embodiments. In addition, at least some of the openings 64 formed between adjacent filaments 14 of the permeable shell 40 of the device 10 may be configured to allow blood flow through the openings 64 only at a velocity below a thrombotic threshold velocity. For some embodiments, the largest openings 64 in the permeable shell structure 40 may be configured to allow blood flow through the openings 64 only at a velocity below a thrombotic threshold velocity. As discussed above, the pore size may be less than about 0.016 inches, more specifically, less than about 0.012 inches for some embodiments. For some embodiments, the openings 64 formed between adjacent filaments 14 may be about 0.005 inches to about 0.04 inches.
Implants placed within the aneurysm sac initially provide flow stasis, then serve as “scaffolding” for clotting and cell growth. After the aneurysm is fully clotted and cell growth begins, the intrasaccular implant would ideally dissolve or degrade to allow the aneurysm to continue healing naturally (and fully) as discussed above. It is very challenging, however, to construct fully biodegradable implants because materials that dissolve in the body are generally very soft and/or non-superelastic. The following embodiments address this issue and may generally relate to occlusive devices that promote healing and shrinkage or contraction of the aneurysm through treatment with implants that reduce in size over time.
Implants placed within the aneurysm sac initially provide flow stasis, then serve as “scaffolding” for clotting and cell growth. After the aneurysm is fully clotted and cell growth begins, the intrasaccular implant would ideally dissolve or degrade to allow the aneurysm to continue healing naturally (and fully) as discussed above. It is very challenging, however, to construct fully biodegradable implants because materials that dissolve in the body are generally very soft and/or non-superelastic. The following embodiments address this issue.
A device for treating an aneurysm is depicted in
As seen in
As seen in
As seen in
In another embodiment,
The mesh or braided portion 248 in the proximal region 246 may extend from the proximal end 242 to a position of the device that is less than a full length of the implant. For example, the mesh or braided portion 248 may extend from the proximal end 242 to a region that is approximately half-way between the proximal 242 and distal 244 ends, alternatively to a region that is between approximately ⅓ and ⅔ between the proximal 242 and distal 244 ends. Alternatively, the mesh or braided portion 248 may extend less than approximately 80%, alternatively less than approximately 70%, alternatively less than approximately 60%, alternatively less than approximately 50%, alternatively less than approximately 40%, alternatively less than approximately 30% of the total length of the implant (or a length of the expanded state of the expandable frame formed by the plurality of biodegradable wires or filaments 250) from the proximal end 242. The mesh or braided portion 248 may be made from a plurality of filaments in a woven structure that are secured relative to each other at the proximal end, e.g., in proximal marker band 270 with the proximal ends of the biodegradable wires or filaments 250. The distal end 278 of the mesh or braided portion 248 may be open. Each of the filaments making up the braided portion 248 may be secured at a proximal end in a hub 270 and the distal ends of each of the filaments may not be secured together. The distal ends of each of the filaments making up the braided portion 248 may define a generally circular opening. In an alternative embodiment, each of the first and second ends of the plurality of filaments in the woven structure may be secured together at the proximal end, such that the woven structure is a double layer, and a middle portion of each of the plurality of filaments define the opening at the distal end of the braided portion 248.
The mesh or braided portion 248 may have a flat or recessed proximal end and a curved region that extends from the flat or recessed proximal end to a distal end 278 of the mesh or braided portion 248. The curved region of the mesh or braided portion 248 may have a single radius of curvature and may define a smooth curve. The single radius of curvature of the mesh or braided portion 248 may be different, e.g., larger or smaller, than the single radius of curvature of the biodegradable wires or filaments 250. In one embodiment, the single radius of curvature of the mesh or braided portion 248 is larger than the single radius of curvature of the biodegradable wires or filaments 250 such that a gap may exist between a portion of the mesh or braided portion 248 in the proximal region 246 of the implant. In some embodiments, due to the substantially flat portion of the proximal end of the mesh or braided portion 248, a gap may exist between a portion of the mesh or braided portion 248 and the biodegradable wires or filaments 250 in the proximal region 246 of the implant. Although the mesh or braded portion 248 may not contact the biodegradable wires or filaments 250 in a proximal portion of the implant due to the difference in shape or curvature of the mesh and biodegradable filaments, the mesh or braided portion 248 in a distal region or at the distal end 278 may be adjacent to or in contact with a portion of the biodegradable wires or filaments 250, for example, in a middle region of the implant 210. The biodegradable wires or filaments 250 may be in contact with an inner surface of the mesh or braded portion 248, such that an outer surface of the mesh or braided portion 248 may be part of an outer surface of the implant 210.
In some embodiments, a proximal region of the mesh or braided portion 248 does not contact a proximal region of the expandable frame made from the biodegradable wires or filaments 250. In some embodiments, the height of the portion of the mesh or braided portion 248 not in contact with the biodegradable wires or filaments 250 may be between about 10% and about 90%, alternatively between about 20% and about 90%, alternatively between about 30% and about 90%, alternatively between about 40% and about 90%, alternatively between about 50% and about 90%, alternatively between about 60% and about 90%, alternatively between about 40% and about 80%, alternatively between about 30% and about 700% of the total height of the mesh or braided portion 248 in the expanded state. In some embodiments, the height of the portion of the biodegradable wires or filaments 250 not in contact with the mesh or braided portion 248 may be between about 10% and about 70%, alternatively between about 10% and about 60%, alternatively between about 10% and about 50%, alternatively between about 10% and about 40%, alternatively between about 5% and about 50%, alternatively between about 5% and about 30%.
The plurality of filaments that make up the mesh or braided portion 248 may be made from nitinol, stainless steel, drawn filled tubing (e.g., platinum or tantalum core with a nitinol jacket), platinum, platinum alloys such as platinum/tungsten, or a mixture thereof. The distal end 278 of the mesh or braided portion 248 can be secured to at least one, alternatively at least two or more, of the biodegradable wires or filaments 250 with a radiopaque material. The wires may have a diameter of about 0.001 inches to about 0.003 inches, alternatively about 0.0015 inches to about 0.0025 inches. Suitable materials and sizes of wires for constructing mesh implants are described in US 2017/0095254, US 2016/0249934, US 2016/0367260, US 2016/0249937, and US 2018/0000489, all of which are hereby expressly incorporated by reference in their entirety for all purposes.
The permeable shell 240 of the device 210 has a radially constrained elongated state configured for delivery within a microcatheter, with the thin woven filaments extending longitudinally from the proximal end to the distal end of the permeable shell radially adjacent each other along a length of the filaments. The permeable shell 240 has an expanded relaxed state with a globular or barrel-like, longitudinally shortened configuration relative to the radially constrained state. In the expanded state, mesh or braided portion 248 and the biodegradable wires or filaments 250 form the self-expanding resilient permeable shell 240 in a smooth path radially expanded from a longitudinal axis of the permeable shell between the proximal end 242 and distal end 244. The expanded state of the permeable shell 240 may have a diameter of about 4 mm, alternatively about 5 mm, alternatively about 6 mm, alternatively about 7 mm, alternatively about 8 mm, alternatively about 9 mm, alternatively about 10 mm, alternatively about 11 mm. The expanded state of the permeable shell 240 may have a height or length of about 2.6 mm, about 3 mm, about 3.6 mm, about 4 mm, about 4.6 mm, about 5 mm, about 5.6 mm, about 6 mm, about 6.6 mm, about 7 mm, about 7.6 mm, about 8 mm, about 8.6 mm, about 9 mm, about 9.6 mm, or about 10 mm. The woven structure of the filaments forming the mesh or braided portion 248 includes a plurality of openings in the mesh or braided portion 248 formed between the woven filaments. In some embodiments, the occlusive device 210 can be configured as an intrasaccular occlusive device which generally conforms to the shape of the treatment site. The device 210 may be comparable to other implants in which the mesh extends from the proximal to distal end of the device in terms of both radial and axial strength.
For some embodiments, the permeable shell 40 or portions thereof or mesh portions 148, 158, 248 may be porous and may be highly permeable to liquids. In contrast to most vascular prosthesis fabrics or grafts which typically have a water permeability below 2,000 ml/min/cm2 when measured at a pressure of 120 mmHg, the permeable shell 40 or mesh portions 148, 158, 248 discussed herein may have a water permeability greater than about 2,000 ml/min/cm2, in some cases greater than about 2,500 ml/min/cm2. For some embodiments, water permeability of the permeable shell 40 or portions thereof or mesh portions 148, 158, 248 may be between about 2,000 and 10,000 ml/min/cm2, more specifically, about 2,000 ml/min/cm2 to about 15,000 ml/min/cm2, when measured at a pressure of 120 mmHg.
Device embodiments and components thereof may include metals, polymers, biologic materials and composites thereof. Suitable metals include zirconium-based alloys, cobalt-chrome alloys, nickel-titanium alloys, platinum, tantalum, stainless steel, titanium, gold, and tungsten. Potentially suitable polymers include but are not limited to acrylics, silk, silicones, polyvinyl alcohol, polypropylene, polyvinyl alcohol, polyesters (e.g. polyethylene terephthalate or PET), PolyEtherEther Ketone (PEEK), polytetrafluoroethylene (PTFE), polycarbonate urethane (PCU) and polyurethane (PU). Device embodiments may include a material that degrades or is absorbed or eroded by the body. A bioresorbable (e.g., breaks down and is absorbed by a cell, tissue, or other mechanism within the body) or bioabsorbable (similar to bioresorbable) material may be used. Alternatively, a bioerodable (e.g., erodes or degrades over time by contact with surrounding tissue fluids, through cellular activity or other physiological degradation mechanisms), biodegradable (e.g., degrades over time by enzymatic or hydrolytic action, or other mechanism in the body), or dissolvable material may be employed. Each of these terms is interpreted to be interchangeable. bioabsorbable polymer. Potentially suitable bioabsorbable materials include polylactic acid (PLA), poly(alpha-hydroxy acid) such as poly-L-lactide (PLLA), poly-D-lactide (PDLA), polyglycolide (PGA), polydioxanone, polycaprolactone, polygluconate, polylactic acid-polyethylene oxide copolymers, modified cellulose, collagen, poly(hydroxybutyrate), polyanhydride, polyphosphoester, poly(amino acids), or related copolymer materials. An absorbable composite fiber may be made by combining a reinforcement fiber made from a copolymer of about 18% glycolic acid and about 82% lactic acid with a matrix material consisting of a blend of the above copolymer with about 20% polycaprolactone (PCL).
Permeable shell embodiments 40 or portions thereof or mesh portions 148, 158, 248 may be formed at least in part of wire, ribbon, or other filamentary elements 14. These filamentary elements 14 may have circular, elliptical, ovoid, square, rectangular, or triangular cross-sections. Permeable shell embodiments 40 or portions thereof or mesh portions 148, 158, 248 may also be formed using conventional machining, laser cutting, electrical discharge machining (EDM) or photochemical machining (PCM). If made of a metal, it may be formed from either metallic tubes or sheet material.
Device embodiments discussed herein may be delivered and deployed from a delivery and positioning system 112 that includes a microcatheter 61, such as the type of microcatheter 61 that is known in the art of neurovascular navigation and therapy. Device embodiments for treatment of a patient's vasculature may be elastically collapsed and restrained by a tube or other radial restraint, such as an inner lumen 120 of a microcatheter 61, for delivery and deployment. The microcatheter 61 may generally be inserted through a small incision 152 accessing a peripheral blood vessel such as the femoral artery or brachial artery. The microcatheter 61 may be delivered or otherwise navigated to a desired treatment site 154 from a position outside the patient's body 156 over a guidewire 159 under fluoroscopy or by other suitable guiding methods. The guidewire 159 may be removed during such a procedure to allow insertion of the device secured to a delivery apparatus 111 of the delivery system 112 through the inner lumen 120 of a microcatheter 61 in some cases.
Access to a variety of blood vessels of a patient may be established, including arteries such as the femoral artery 166, radial artery 164, and the like in order to achieve percutaneous access to a vascular defect 160. In general, the patient 158 may be prepared for surgery and the access artery is exposed via a small surgical incision 152 and access to the lumen is gained using the Seldinger technique where an introducing needle is used to place a wire over which a dilator or series of dilators dilates a vessel allowing an introducer sheath 162 to be inserted into the vessel. This would allow the device to be used percutaneously. With an introducer sheath 162 in place, a guiding catheter 168 is then used to provide a safe passageway from the entry site to a region near the target site 154 to be treated. For example, in treating a site in the human brain, a guiding catheter 168 would be chosen which would extend from the entry site 152 at the femoral artery up through the large arteries extending around the heart through the aortic arch, and downstream through one of the arteries extending from the upper side of the aorta such as the carotid artery 170. Typically, a guidewire 159 and neurovascular microcatheter 61 are then placed through the guiding catheter 168 and advanced through the patient's vasculature, until a distal end 151 of the microcatheter 61 is disposed adjacent or within the target vascular defect 160, such as an aneurysm. Exemplary guidewires 159 for neurovascular use include the Synchro2® made by Boston Scientific and the Glidewire Gold Neuro® made by MicroVention Terumo. Typical guidewire sizes may include 0.014 inches and 0.018 inches. Once the distal end 151 of the catheter 61 is positioned at the site, often by locating its distal end through the use of radiopaque marker material and fluoroscopy, the catheter is cleared. For example, if a guidewire 159 has been used to position the microcatheter 61, it is withdrawn from the catheter 61 and then the implant delivery apparatus 111 is advanced through the microcatheter 61.
Delivery and deployment of device embodiments discussed herein may be carried out by first compressing the device to a radially constrained and longitudinally flexible state as shown in
Once disposed within the vascular defect 160, the device may then allowed to assume an expanded relaxed or partially relaxed state with the permeable shell 40 or portions thereof or mesh portions 148, 158, 248 of the device spanning or partially spanning a portion of the vascular defect 160 or the entire vascular defect 160. The device may also be activated by the application of an energy source to assume an expanded deployed configuration once ejected from the distal section of the microcatheter 61 for some embodiments. Once the device is deployed at a desired treatment site 154, the microcatheter 61 may then be withdrawn.
Some embodiments of devices for the treatment of a patient's vasculature discussed herein may be directed to the treatment of specific types of defects of a patient's vasculature. For example, referring to
Prior to delivery and deployment of a device for treatment of a patient's vasculature it may be desirable for the treating physician to choose an appropriately sized device to optimize the treatment results. Some embodiments of treatment may include estimating a volume of a vascular site or defect 160 to be treated and selecting a device with a volume that is substantially the same volume or slightly over-sized relative to the volume of the vascular site or defect 160. The volume of the vascular defect 160 to be occluded may be determined using three-dimensional angiography or other similar imaging techniques along with software which calculates the volume of a selected region. The amount of over-sizing may be between about 2% and 15% of the measured volume. In some embodiments, such as a very irregular shaped aneurysm, it may be desirable to under-size the volume of the device. Small lobes or “daughter aneurysms” may be excluded from the volume, defining a truncated volume which may be only partially filled by the device without affecting the outcome. A device deployed within such an irregularly shaped aneurysm 160 is shown in
In particular, for some treatment embodiments, it may be desirable to choose a device 10, 110, 210 that is properly oversized in a transverse dimension so as to achieve a desired conformance, radial force and fit after deployment of the device.
In
Once a properly sized device has been selected, the delivery and deployment process may then proceed. It should also be noted also that the properties of the device embodiments and delivery system embodiments 112 discussed herein generally allow for retraction of a device after initial deployment into a defect 160, but before detachment of the device. Therefore, it may also be possible and desirable to withdraw or retrieve an initially deployed device after the fit within the defect 160 has been evaluated in favor of a differently sized device. An example of a terminal aneurysm 160 is shown in
Detachment of the device from the delivery apparatus 111 may be controlled by a control switch 188 disposed at a proximal end of the delivery system 112, which may also be coupled to an energy source 142, which severs the tether 72 that secures the proximal hub 68 of the device to the delivery apparatus 111. While disposed within the microcatheter 61 or other suitable delivery system 112, as shown in
The device may be inserted through the microcatheter 61 such that the catheter lumen 120 restrains radial expansion of the device during delivery. Once the distal tip or deployment port of the delivery system 112 is positioned in a desirable location adjacent or within a vascular defect 160, the device may be deployed out the distal end of the catheter 61 thus allowing the device to begin to radially expand as shown in
Upon full deployment, radial expansion of the device may serve to secure the device within the vascular defect 160 and also deploy the device across at least a portion of an opening 190 (e.g. aneurysm neck) so as to at least partially isolate the vascular defect 160 from flow, pressure or both of the patient's vasculature adjacent the vascular defect 160 as shown in
For some embodiments, as discussed above, the device may be manipulated by the user to position the device within the vascular site or defect 160 during or after deployment but prior to detachment. For some embodiments, the device may be rotated in order to achieve a desired position of the device and, more specifically, a desired position of the permeable shell 40 or portions thereof or mesh portions 148, 158, 248, prior to or during deployment of the device. For some embodiments, the device may be rotated about a longitudinal axis of the delivery system 112 with or without the transmission or manifestation of torque being exhibited along a middle portion of a delivery catheter being used for the delivery. It may be desirable in some circumstances to determine whether acute occlusion of the vascular defect 160 has occurred prior to detachment of the device from the delivery apparatus 111 of the delivery system 112. These delivery and deployment methods may be used for deployment within berry aneurysms, terminal aneurysms, or any other suitable vascular defect embodiments 160. Some method embodiments include deploying the device at a confluence of three vessels of the patient's vasculature that form a bifurcation such that the permeable shell 40 or portions thereof or mesh portions 148, 248 of the device substantially covers the neck of a terminal aneurysm. Once the physician is satisfied with the deployment, size and position of the device, the device may then be detached by actuation of the control switch 188 by the methods described above and shown in
Markers, such as radiopaque markers, on the device or delivery system 112 may be used in conjunction with external imaging equipment (e.g., x-ray) to facilitate positioning of the device or delivery system during deployment. Once the device is properly positioned, the device may be detached by the user. For some embodiments, the detachment of the device from the delivery apparatus 111 of the delivery system 112 may be affected by the delivery of energy (e.g. heat, radiofrequency, ultrasound, vibrational, or laser) to a junction or release mechanism between the device and the delivery apparatus 111. Once the device has been detached, the delivery system 112 may be withdrawn from the patient's vasculature or patient's body 158. For some embodiments, a stent 173 may be place within the parent vessel substantially crossing the aneurysm neck 190 after delivery of the device 10 as shown in
For some embodiments, a biologically active agent or a passive therapeutic agent may be released from a responsive material component of the device. The agent release may be affected by one or more of the body's environmental parameters or energy may be delivered (from an internal or external source) to the device. Hemostasis may occur within the vascular defect 160 as a result of the isolation of the vascular defect 160, ultimately leading to clotting and substantial occlusion of the vascular defect 160 by a combination of thrombotic material and the device. For some embodiments, thrombosis within the vascular defect 160 may be facilitated by agents released from the device and/or drugs or other therapeutic agents delivered to the patient.
For some embodiments, once the device has been deployed, the attachment of platelets to the permeable shell 40 or portions thereof or mesh portions 148, 158, 248 may be inhibited and the formation of clot within an interior space of the vascular defect 160, device, or both promoted or otherwise facilitated with a suitable choice of thrombogenic coatings, anti-thrombogenic coatings or any other suitable coatings (not shown) which may be disposed on any portion of the device for some embodiments, including an outer surface of the filaments or the proximal and distal hubs. Such a coating or coatings may be applied to any suitable portion of the permeable shell 40. Energy forms may also be applied through the delivery apparatus 111 and/or a separate catheter to facilitate fixation and/or healing of the device adjacent the vascular defect 160 for some embodiments. One or more embolic devices or embolic material 176 may also optionally be delivered into the vascular defect 160 adjacent permeable shell portion that spans the neck or opening 190 of the vascular defect 160 after the device has been deployed. For some embodiments, a stent or stent-like support device 173 may be implanted or deployed in a parent vessel adjacent the defect 160 such that it spans across the vascular defect 160 prior to or after deployment of the vascular defect treatment device.
In any of the above embodiments, the device may have sufficient radial compliance so as to be readily retrievable or retractable into a typical microcatheter 61. The proximal portion of the device, or the device as a whole for some embodiments, may be engineered or modified by the use of reduced diameter filaments, tapered filaments, or filaments oriented for radial flexure so that the device is retractable into a tube that has an internal diameter that is less than about 0.7 mm, using a retraction force less than about 2.7 Newtons (0.6 lbf) force. The force for retrieving the device into a microcatheter 61 may be between about 0.8 Newtons (0.18 lbf) and about 2.25 Newtons (0.5 lbf).
Engagement of the permeable shell 40 or portions thereof or mesh portions 148, 158, 248 with tissue of an inner surface of a vascular defect 160, when in an expanded relaxed state, may be achieved by the exertion of an outward radial force against tissue of the inside surface of the cavity of the patient's vascular defect 160, as shown for example in
Various aspects of the present subject matter are set forth below, in review of, and/or in supplementation to, the embodiments described thus far, with the emphasis here being on the interrelation and interchangeability of the following embodiments. In other words, an emphasis is on the fact that each feature of the embodiments can be combined with each and every other feature unless explicitly stated otherwise or logically implausible. The embodiments described herein are restated and expanded upon in the following paragraphs without explicit reference to the figures.
In many embodiments, a device for treatment of a patient's cerebral aneurysm includes: an expandable frame having a proximal end, a distal end, a middle region between the proximal and distal ends, a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate biodegradable filaments that extend from the proximal end to the distal end; and a permeable shell having a radially constrained elongated state configured for delivery within the catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh, wherein in the expanded state, the permeable shell extends from the proximal end of the expandable frame to the middle region of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is smaller than a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is about half a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is between about ¼ and about ¾ of a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is between about ⅓ and about ⅔ of a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is less than approximately 60% of a length of the expanded state of the expandable frame.
In some embodiments, an inner surface of second permeable shell is in contact with an outer surface of the expandable frame.
In some embodiments, a diameter of the expanded state of the permeable shell in a proximal region is larger than a diameter of the expanded state of the expandable frame in a proximal region.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the proximal ends of each of the plurality of filaments of the permeable shell and the proximal ends of the plurality of elongate biodegradable filaments are gathered in a hub. In some embodiments, the hub is radiopaque.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the distal ends of each of the plurality of filaments of the permeable shell are not gathered in a hub.
In some embodiments, the permeable shell has an open distal end.
In some embodiments, the expanded state of the permeable shell has a recessed proximal end.
In some embodiments, a proximal end of the expanded state of the permeable shell has a concave portion.
In some embodiments, a proximal end of the expanded state of the permeable shell has a substantially flat portion. In some embodiments, the substantially flat portion comprises a concave portion that includes a hub.
In some embodiments, in the expanded state, a proximal region of the permeable shell does not contact a proximal region of the expandable frame.
In some embodiments, in the expanded state, a height of a portion of the permeable shell that does not contact the expandable frame is between about 20% to about 90% of a total height of the permeable shell.
In many embodiments, a method for treating a cerebral aneurysm having an interior cavity and a neck includes the steps of: advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises: an expandable frame having a proximal end, a distal end, a middle region between the proximal and distal ends, a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate biodegradable filaments that extend from the proximal end to the distal end; and a permeable shell having a radially constrained elongated state configured for delivery within the catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh, wherein in the expanded state, the permeable shell extends from the proximal end of the expandable frame to the middle region of the expandable frame; deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and withdrawing the microcatheter from the region of interest after deploying the implant.
In some embodiments, the implant is advanced through a lumen of the microcatheter by advancing a pusher the is detachably coupled to a distal end of the implant, further comprising the step of detaching the implant from the pusher. In some embodiments, the implant is detachably coupled to the distal end of the pusher through a thermal, mechanical, or electrolytic mechanism.
In some embodiments, a length of the expanded state of the permeable shell is smaller than a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is about half a length of the expanded state of the expandable frame.
In some embodiments, a length of the expanded state of the permeable shell is less than approximately 60% of a length of the expanded state of the expandable frame.
In some embodiments, an inner surface of second permeable shell is in contact with an outer surface of the expandable frame.
In some embodiments, each of the plurality of filaments of the permeable shell have a proximal and distal end, wherein the proximal ends of each of the plurality of filaments of the permeable shell and the proximal ends of the plurality of elongate biodegradable filaments are gathered in a hub.
In some embodiments, a proximal end of the expanded state of the permeable shell has a substantially flat portion. In some embodiments, the substantially flat portion comprises a concave portion that includes a hub.
In some embodiments, in the expanded state, a proximal region of the permeable shell does not contact a proximal region of the expandable frame.
In some embodiments, in the expanded state, a height of a portion of the permeable shell that does not contact the expandable frame is between about 20% to about 90% of a total height of the permeable shell.
In many embodiments, a device for treatment of a patient's cerebral aneurysm includes: a first permeable shell formed from a first plurality of elongate filaments that are woven together to form a mesh, the first permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within a catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a proximal end of each of the plurality of elongate filaments are gathered at the proximal end of the first permeable shell, and wherein the expanded state has an open distal end; and a second permeable shell formed from a second plurality of elongate filaments that are woven together to form a mesh, the second permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within the catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a distal end of each of the second plurality of elongate filaments are gathered at the distal end of the second permeable shell, and wherein the expanded state has an open proximal end, and wherein the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together.
In some embodiments, the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together with a biodegradable filament. In some embodiments, the biodegradable filament comprises PGLA. In some embodiments, the biodegradable filament is a plurality of biodegradable filaments.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first length and the open distal end of the expanded state of the second permeable shell has a second length, and wherein the second length is smaller than the first length. In some embodiments, the first length is a first diameter and the second length is a second diameter.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first perimeter and the open distal end of the expanded state of the second permeable shell has a second perimeter, and wherein the second perimeter is smaller than the first perimeter.
In some embodiments, a height of the first permeable shell is about equal to a height of the second permeable shell.
In some embodiments, a height of the first permeable shell is longer than a height of the second permeable shell.
In some embodiments, the first permeable shell comprises an inner cavity, wherein the second permeable shell is configured to at least partially fit within the inner cavity.
In some embodiments, the open distal end of the first permeable shell has a substantially circular shape.
In some embodiments, the open proximal end of the second permeable shell has a substantially circular shape.
In some embodiments, at least a portion of the first permeable shell has a convex outer surface.
In some embodiments, at least a portion of the second permeable shell has a convex outer surface.
In some embodiments, the proximal end of the first permeable shell has a recessed portion.
In some embodiments, the distal end of the second permeable shell has a recessed portion.
In many embodiments, a method for treating a cerebral aneurysm having an interior cavity and a neck includes the steps of: advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises: a first permeable shell formed from a first plurality of elongate filaments that are woven together to form a mesh, the first permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within a catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a proximal end of each of the plurality of elongate filaments are gathered at the proximal end of the first permeable shell, and wherein the expanded state has an open distal end; and a second permeable shell formed from a second plurality of elongate filaments that are woven together to form a mesh, the second permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within the catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a distal end of each of the second plurality of elongate filaments are gathered at the distal end of the second permeable shell, and wherein the expanded state has an open proximal end, and wherein the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together; deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and withdrawing the microcatheter from the region of interest after deploying the implant.
In some embodiments, the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together with a biodegradable filament. In some embodiments, the biodegradable filament comprises PGLA.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first length and the open distal end of the expanded state of the second permeable shell has a second length, and wherein the second length is smaller than the first length.
In some embodiments, the first length is a first diameter and the second length is a second diameter.
In some embodiments, the open distal end of the expanded state of the first permeable shell has a first perimeter and the open distal end of the expanded state of the second permeable shell has a second perimeter, and wherein the second perimeter is smaller than the first perimeter.
In some embodiments, a height of the first permeable shell is about equal to a height of the second permeable shell.
In some embodiments, a height of the first permeable shell is longer than a height of the second permeable shell.
In some embodiments, the first permeable shell comprises an inner cavity, wherein the second permeable shell is configured to at least partially fit within the inner cavity.
In some embodiments, the open distal end of the first permeable shell has a substantially circular shape, and wherein the open proximal end of the second permeable shell has a substantially circular shape.
In some embodiments, at least a portion of the first permeable shell has a convex outer surface, and wherein at least a portion of the second permeable shell has a convex outer surface.
In some embodiments, the proximal end of the first permeable shell has a recessed portion.
In some embodiments, the distal permeable shell moves proximally such that at least a portion of the distal permeable shell resides in an inner cavity of the proximal permeable shell after the biodegradable filament degrades.
Although the foregoing invention has, for the purposes of clarity and understanding, been described in some detail by way of illustration and example, it will be obvious that certain changes and modifications may be practiced which will still fall within the scope of the appended claims.
The subject matter described herein and in the accompanying figures is done so with sufficient detail and clarity to permit the inclusion of claims, at any time, in means-plus-function format pursuant to 35 U.S.C. section 112, part (f). However, a claim is to be interpreted as invoking this means-plus-function format only if the phrase “means for” is explicitly recited in that claim.
Aspects of the invention are set out in the independent claims and preferred features are set out in the dependent claims. The preferred features of the dependent claims may be provided in combination in a single embodiment and preferred features of one aspect may be provided in conjunction with other aspects.
As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.
While the embodiments are susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. These embodiments are not to be limited to the particular form disclosed, but to the contrary, these embodiments are to cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure. Furthermore, any features, functions, steps, or elements of the embodiments may be recited in or added to the claims, as well as negative limitations that define the scope of the claims by features, functions, steps, or elements that are not within that scope.
Exemplary embodiments are set out in the following numbered clauses.
an expandable frame having a proximal end, a distal end, a middle region between the proximal and distal ends, a radially constrained elongated state configured for delivery within a catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate biodegradable filaments that extend from the proximal end to the distal end; and
a permeable shell having a radially constrained elongated state configured for delivery within the catheter lumen, an expanded state with a longitudinally shortened configuration relative to the radially constrained state, and a plurality of elongate filaments that are woven together to form a mesh,
wherein in the expanded state, the permeable shell extends from the proximal end of the expandable frame to the middle region of the expandable frame.
advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises:
deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and
withdrawing the microcatheter from the region of interest after deploying the implant.
a first permeable shell formed from a first plurality of elongate filaments that are woven together to form a mesh, the first permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within a catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a proximal end of each of the plurality of elongate filaments are gathered at the proximal end of the first permeable shell, and wherein the expanded state has an open distal end; and
a second permeable shell formed from a second plurality of elongate filaments that are woven together to form a mesh, the second permeable shell having a proximal end, a distal end, a radially constrained elongated state configured for delivery within the catheter lumen, and an expanded state with a longitudinally shortened configuration relative to the radially constrained state, wherein a distal end of each of the second plurality of elongate filaments are gathered at the distal end of the second permeable shell, and wherein the expanded state has an open proximal end, and
wherein the distal end of the first permeable shell and the proximal end of the second permeable shell are releasably coupled together.
advancing an implant in a microcatheter to a region of interest in a cerebral artery, wherein the implant comprises:
deploying the implant within the cerebral aneurysm, wherein the permeable shell expands to the expanded state in the interior cavity of the aneurysm; and
withdrawing the microcatheter from the region of interest after deploying the implant.
This application claims the benefit of priority under 35 U.S.C. § 119(e) from U.S. Provisional Application Ser. No. 63/127,550, filed Dec. 18, 2020, which is hereby incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63127550 | Dec 2020 | US |
