Patent Application
20170216068
The present invention relates to devices, systems, and methods for reducing or preventing the migration of a radially expandable stent during implantation in a lumen, bodily conduit, or vasculature of a patient or subject.
Implantable medical stents used for the repair or reinforcement of cardiac and vascular structures are well-known in the art. Such devices are implanted on an interior side of a vascular lumen often using standard interventional or endovascular techniques. By way of example, the target site of the vascular lumen is surgically accessed by an arterial or venous point of entry. A distal end of a medical device (e.g. catheter) that contains the stent is threaded from this point along the artery or vein to the targeted region. The implantable component is then deployed and affixed to the vascular lumen wall (often using an expandable stent and/or angioplasty balloon), and the remainder of the distal portion of the medical device assembly is removed.
In one application, such stents are provided to maintain vascular access during long-term hemodialysis and to counteract the stenosis commonly observed as a side-effect. This is often accomplished by implanting of one or multiple stents in either or both arterial and venous structures being used in the procedure. With the former, the arterial vessel walls can act as a natural barrier preventing stent migration during implantation. That is, blood flowing through the artery may cause the stent to migrate away from the target site. But even if this is observed, vessel narrowing will eventually impede the progress of the stent.
This is not the case with the venous system, however. As a stent is deployed using many of the currently existing systems, methods or devices, it may migrate with the blood flow toward the heart. This is particularly true in instances where blood flow rate is much higher, i.e. at target locations closer to the heart. Stent migration in such cases can have dire consequences for the patient and, in certain cases, can be fatal. Accordingly, a device, system, and method for reducing or preventing stent migration prior to and during stent deployment is desirable.
U.S. Pat. No. 6,984,242 (“the '242 patent”) discloses an applicator for a stent that contains barrier elements 67 and 68 adjacent to the stent's distal and proximal ends. While these barrier elements are intended to assist in confining the stent to the delivery catheter. It fails to provide a barrier element that prevents stent migration as or immediately after it is deployed.
That is, as the stent is expanded beyond the diameter of these elements but before it is affixed to the vessel wall, the stent may still migrate with the blood flow over barrier elements 67 or 68 and away from the targeted site. Accordingly, at least as it pertains to the problem identified herein, the '242 patent does not provide an adequate solution.
In certain non-limiting aspects, the present invention relates to a stent delivery assembly for implanting a radially expandable endoluminal stent. In certain aspects, the invention relates to a retention element for a stent delivery assembly that includes a housing having a lumen passing therethrough, where the lumen is sized to receive a catheter. Two or more arms are coupled to the housing at a first end and adapted at a second end to be convertible between a first position radially extending from the housing or a second position received within a corresponding cut-out in the housing. A film, or plurality of films, is coupled to the housing such that a diameter of the film, or collectively of the plurality of films, is greater when the two or more arms are in the first position than in the second position. Such a retention element, in certain aspects, is adapted to control the flow of fluid in and around a stent implantation site during implantation of the stent within the patient. Such an element may also be adapted to reduce and/or prevent migration of the stent prior to and during implantation within a patient.
In certain non-limiting aspects, the housing includes a hollow conical end coupled to a hollow shaft, where the hollowed portions are aligned to form the lumen. The housing may be manufactured from one or more of a metallic component, a polymeric component, and/or a superelastic component. Non-limiting examples include, but are not limited to, high-density polyethylene material, polyvinylchloride, shape memory alloys, or the like.
The arms may be pre-stressed, such as a flat spring, to maintain the first position by default. To this end, the arms exert a radial force outward from the housing when in the second position. At or about its second end, the arms may also include one or more extensions radially therefrom. The film (or plurality of films) may optionally include one or more holes, which may be sized and provided to control fluid flow in and through the stent implantation site.
In further embodiments, the present invention relates to a stent delivery assembly for implanting a radially expandable endoluminal stent that includes a radially expandable endoluminal stent mounted on an external surface of a delivery tube, the stent having a distal end and a proximal end. A first retention element is mounted on the delivery tube at or adjacent to the distal or proximal end of the expandable endoluminal stent and has the structure provided above. A second retention element is also mounted on the delivery tube at or adjacent to the other of the distal or proximal end of the expandable endoluminal stent and over an opening in the tube.
The present invention also relates to methods of using such a stent delivery assembly, or adaptations thereof, for the implantation of a stent into a patient. In certain aspects, such a method includes inserting a distal end of the delivery tube into a bodily conduit of a subject or patient; expanding, radially, at least one of the first and second retention elements; expanding, radially, the stent; and deflating the expanded first and/or second retention element
In further embodiments, the present invention relates to a stent delivery assembly for implanting a radially expandable endoluminal stent that includes a radially expandable endoluminal stent mounted on an external surface of a delivery tube, the stent having a distal end and a proximal end. A first retention element is mounted on the delivery tube at or adjacent to the distal or proximal end of the expandable endoluminal stent and has the structure provided above. A second retention element is mounted on the delivery tube at or adjacent to the proximal end of the expandable endoluminal stent and also has the structure provided above and described herein.
The present invention also relates to methods of using such a stent delivery assembly, or adaptations thereof, for the implantation of a stent into a patient. In certain aspects, such a method includes inserting a distal end of the delivery tube into a bodily conduit of a subject or patient; expanding, radially, at least one of the first and second retention elements; expanding, radially, the stent; and deflating or contracting the expanded first and/or second retention element Applicants assert that the foregoing embodiments, and advantages to such embodiments, are not limiting to the present invention. Additional embodiments and advantages will be readily apparent to one of skill of the art on the basis of at least the remaining disclosure provided herein.
In certain aspects, the present invention relates to a device, system and associated methods for reducing or preventing migration of a stent during and immediately post-deployment within a bodily conduit or lumen. Referring to
In one aspect, the delivery mechanism 4 is a longitudinal tube, such as but not limited to a catheter, of sufficient length to reach from a point of entry in a patient to the targeted site of stent deployment. The tube 4 is hollow and contains one or multiple separate lumens. A distal end 26 of the tube is adapted to enter into the vasculature, bodily lumen, or conduit of a patient and be threaded within the body to the target site. A proximal end 28 of the tube 4 is adapted to be received by the deployment handle 12, which has one or more ports adapted to provide access the lumen(s) of the tube. In certain aspects, and referring to
The second lumen 16 of tube 4 may be provided for access to the stent device 6 and to facilitate deployment of it once it has reached the target site. Specific mechanisms of such deployment are discussed in greater detail below. The lumen may be of any diameter, size, or shape to facilitate deployment in accordance with the embodiments of the present invention.
The third lumen 18 may be provided to effectuate expansion of the stent retention elements 8 and 10. One lumen may be provided, as illustrated, to access both expandable stent retention elements 8, 10. Alternatively, two separate lumens may be provided where each is independently in communication with only one of the two stent retention elements. Specific mechanisms of retention element expansion are discussed in greater detail below. The lumen may be of any diameter, size, or shape to facilitate expansion in accordance with the embodiments of the present invention.
One of skill in the art will readily appreciate that the present invention is not limited to the foregoing three lumen structure or the corresponding uses or configurations of each that are provided herein. Rather, one of skill in the art would readily appreciate that more or fewer lumens may be provided in accordance with the present invention and that alternative uses or configurations may also be provided to effectuate stent delivery in accordance with the various embodiments provided herein.
The stent 6 may be manufactured from any material and provided in any configuration known in the art, particularly, though not exclusively, a material and configuration having the strength and elasticity to permit radial expansion and resistance radial collapse. As illustrated in
While the stent 6 may be manufactured from a solid, but expandable material, in certain aspects, it is provided as wire mesh. The wires may be formed from a biocompatible or inert material including, but not limited to, stainless steel, nickel-titanium alloy (nitinol), tantalum, elgiloy, various polymer materials, such as poly(ethylene terephthalate) (PET) or polytetrafluoroethylene (PTFE), or bioresorbable materials, such as levorotatory polylactic acid (L-PLA) or polyglycolic acid (PGA). In certain aspects, the material comprises a superelastic material, such as nitinol metal, that can withstand tight compression in a compacted configuration and then self-expand to a deployed configuration once released in place. Alternatively, the stent 6 of the present invention may be constructed from a material (e.g., stainless steel) that can be mechanically enlarged in place, such as through balloon expansion.
The stent 6 may be coated on at least a portion of either or both its interior surface and/or exterior surface with a biocompatible coating. The coating may be provided to insulate the material of the stent, e.g. the wire mesh, from contacting the surface of a patient's body, thereby reducing risk of injury or an immunogenic reaction. The coating, in certain aspects, is provided substantially across the entire interior and exterior surface of the stent 6. In such a configuration, it provides a substantially smooth and inert biocompatible surface that may be affixed to the wall of a vasculature, bodily conduit, or lumen within a patient. Such materials, in certain embodiments, have the strength and structural elasticity to permit radial expansion of the stent 6. One non-limiting example of such a coating material that is well-known in the art at includes expanded polytetrafluoroethyulene (ePTFE).
To facilitate placement of the stent 6, a series of radiopaque markers 42, such as circumferential bands, may be provided along its length. In certain embodiments, and as illustrated, the radiopaque markers 42 may be provided on at least the distal and/or proximal ends 22, 24 of the stent. Such elements are well-understood to facilitate fluoroscopic visualization of the stent during deployment and to ensure correct positioning. The stent also may be imbibed with various pharmaceutical agents, biological agents, or genetic therapies for targeted delivery (luminally or otherwise) of these substances. Non-limiting examples of such substances may include anti-thrombogenic agents, anti-microbial agents (e.g. antibiotics, antiviral, anti-fungal, anti-parasitics, etc.), anti-septic agents, anti-proliferative agents, anti-inflammatory agents, anti-neoplastic agents, anti-mitotic agents, anesthetic agents, anti-coagulants, anti-oxidants, angiogenic agents, or any other therapeutic compound, substance, biologic, or agent otherwise known in the art. Following deployment of the stent 6, these agents an be released over time.
The stent 6 may be expandable by any mechanism known in the art. While in certain aspects, the stent 6 may be expanded manually, such as with an angioplasty balloon or similar device, in other aspects, the stent 6 is self-deployable. To this end, the stent 6 is provided at a reduced diameter, which may be at or slightly larger than the diameter of the delivery tube 4. Encapsulating the stent 6 is an exterior constraining sheath 40, which retains the stent 6 in its reduced diameter configuration. The constraining sheath 40 may be manufactured from any material that is able to constrain the expandable stent 6 and may be easily released or removed prior to deployment in the body. In certain non-limiting embodiments, for example, the sheath 40 is manufactured from a biocompatible, inert material, such as ePTFE or any similar polymeric material discussed herein or otherwise known in the art.
Any mechanism for removing the sheath 40 during deployment of the stent may be used.
In one aspect, the sheath 40 can be configured to be removed in place and to remain with the stent 6. For example, the sheath 40 may be provided with a line of perforations through its wall, which are along its length. When pressure is applied on the interior walls of the stent 6, such as with a balloon, the sheath 40 splits along the perforations and the stent 6 is allowed to expand radially. The sheath 40 may be left in place or removed using standard means known in the art.
In an alternative embodiment, the sheath 40 can be withdrawn from the stent 6 so as to effectuate stent deployment. That is, the sheath 40 may be provided with a deployment line (not illustrated) extending from a portion of the sheath adjacent or near the proximal end 24 or distal end 22 of stent 6 through a lumen 16 of the tube and out of port 30 of handle 12 where it can be manipulated by an operator. As illustrated in
In certain embodiments, such as that disclosed in U.S. Pat. No. 7,556,641, the contents of which are incorporated herein by reference in its entirety, a double-walled tubular sheath is used. That is, the walls of the sheath are folded over once such that the folded end is at or near to the distal end 22 of the stent 20. Double walls enable the sheath to be retracted from around an expandable medical device by sliding one wall past the other wall. As the sheath is retracted or unrolled away from the distal end 22 of the stent 20, the sheath portion does not rub or scrape against the underlying expandable medical device.
Though not illustrated, the sheath 40 also may be provided with one or a series of radiopaque markers, such as circumferential bands, along its length and/or at its ends. Such elements are well-understood to facilitate fluoroscopic visualization of the sheath during deployment and to ensure correct relative positioning of the stent.
The pair of expandable stent retention elements 8 and 10 are proximate or adjacent to the distal end 22 and proximal end 24 of the stent 6. In certain aspects, these elements are made from an elastic or expandable material that is adapted to expand to the approximate circumference of the surrounding vasculature. That is, elements 8 and 10 each may be adapted to prevent or reduce blood or fluid flow from moving or migrating the stent 6 as it is deployed into place.
In one non-limiting embodiment, the tube 4 contains at least one opening at or on each side of the stent 6 about which each retention element 8 and 10 is independently mounted. Each element 8 and 10 has a continuous diameter that surrounds an exterior side of the delivery tube 4 and encloses each opening in the delivery tube 4. Each element 8, 10 is independently secured to the tube 4 such that fluid that flows through each opening is contained within the retention element and allows the element to expand without the fluid leaking to the surrounding environment. Methods of securing the retention elements to a delivery tube 4 are well-known in the art and include, but are not limited to, crimping, welding, gluing, or the like. While the placement of the openings on the tube 4 is not necessarily limiting to the invention, in certain aspects the openings, and retention elements 8, 10, should be a sufficient distance from the ends of the stent 6 such that the retention elements, when expanded, will not interfere with stent 6 deployment or radial expansion.
The fluid provided to each retention element may include saline, a radiopaque or contrast dye, air, or any other fluid that is known in the art for use with balloon-based systems, or balloon-tipped catheters. In certain non-limiting aspects, the retention elements 8 and 10 are expanded using contrast dye, which enables operator visualization and control of retention element expansion.
Although not illustrated, one or both retention elements 8, 10 also may be provided with one or a series of radiopaque markers, such as circumferential bands, along its length and/or at its ends. Such elements, as discussed herein, could further facilitate fluoroscopic visualization of the stent during deployment and ensure correct positioning of the assembly and/or of the stent. The contrast fluid and/or radiopaque markers on the retention elements 8 and 10 may be used by the operator to ensure correct positioning of each as and immediately after the retention elements 8 and 10 are expanded.
As indicated above, both retention elements are illustrated as being expanded using a single lumen 18 of the tube 4. That is, through a port 34 in the deployment handle 12 the fluid may be provided such that retention elements 8 and 10 are simultaneously deployed. In alternative embodiments, however, each retention element 8 and 10 may be independently controlled by separate lumens in the delivery tube 4. To this end, the end operator can independently control fluid flow into each retention element and modify the rate at which each element expands or control the expansion of one retention element over the other.
Referring to
Once in place, and as illustrated in
As indicated above, the expansion of the retention elements 8, 10 may be independently controlled through separate lumens of the delivery device. Thus, the present invention is not limited to expansion of retention elements 8, 10 simultaneously during the stent deployment process. In certain aspects, the deployment of one or both retention elements 8, 10 may be temporally off-set where one of the two retention elements is deployed first, and the second deployed thereafter.
The present invention is also not limited to the expansion of both retention elements 8, 10 during the deployment process. In further aspects, only one of the two retention elements 8,10 is expanded. By way of non-limiting example, the retention element 10 most proximal to the handle can be expanded to prevent migration of the stent during stent deployment in an arterial vessel or to reduce/prevent fluid flow during deployment in a vein. Conversely, the retention element 8 most distal to the handle can be expanded to prevent migration of the stent during the deployment in an vein or to reduce/prevent fluid flow during deployment in an artery.
One of skill in the art would readily appreciate that determination of which retention element will be deployed or a time in which one or both retention elements will be deployed can be dependent upon a wide-array of the circumstances surrounding the deployment process. Such circumstances may include, but are not limited to, the type of vessel (e.g. artery or vein), the proximity of the vessel to the heart or a vital organ, the rate of fluid flow through the vessel, the size of the stent, or the like. To this end, the present invention is not limited to any particular rationale for expanding only one retention element or for temporally staggering the expansion of the two retention elements. Rather, the present invention includes the expansion of only one retention element or of both retention elements for any reason during the stent deployment process.
As used herein, the terms “reduce,” “reducing,” or “reduction,” when used in conjunction with fluid flow, refer to any measurable reduction in fluid flow through the bodily conduit vasculature, or lumen of a patient, at least with respect to flow between the two retention elements 8 and 10. With respect to stent migration, these terms mean any measurable reduction in tendency of a stent to migrate, as compared to a device, system, or method not in accordance with the present invention, particularly, though not exclusively a device, system, or method lacking the retention elements 8 or 10. The term “substantially,” when used in conjunction with these terms refers to decreasing the fluid flow or migration by at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% to 100%.
The terms “prevent,” “preventing,” or “prevention,” when used in conjunction with fluid flows refers to stopping entirely fluid flow through the bodily conduit, vasculature, or lumen of a patient, at least with respect to flow between the two retention elements 8 and 10. When used in conjunction with stent migration, these terms refer to stopping the stent from migrating at least beyond retention elements 8 or 10 during deployment of the stent.
Referring to
While not illustrated, the operator can then ensure that the stent 20 is adequately secured to the wall 38 of the bodily conduit using standard means in the art, such as, but not limited to an angioplasty balloon. Once secured, and referring to
One advantage to the foregoing device, system, and method is that migration of the stent 20 is minimized during deployment. The expansion of retention elements 8 and/or 10 prior to deployment of the stent 20, reduces or prevents the fluid flow through the conduit 38 as the stent 20 is deployed. This allows the operator to easily manipulate the stent 20, while minimizing the risk of stent 20 migration. This is particularly, though not exclusively, advantageous when the stent is being deployed in a vein or bodily conduit where fluid flows to a vital organ. In further embodiments, the assembly and methods are advantageous when a stent is desirable in a venous system, such as the deployment of such stents to maintain hemodialysis vascular access. In such instances, the stent can be implanted in accordance with the present invention with significantly lower risk of migration toward or into the heart.
Referring to
The cap 44 may optionally include a beveled edge or one or more stop posts (not illustrated) on an interior side of the lumen 50. Such elements may be sized and positioned to act as a stopping point for the catheter tube within the lumen 50. The cap 44 may also include an off-set portion 56 between the shaft 48 and the conical end 46. Off-set portion 56 may be provided to act as a stopping point for sheath, as described in greater detail below.
The cap 44 may be secured to the tube 4 using standard means in the art. By way of non-limiting example, it may be secured to the tube by way of frictional interaction between the interior walls of the cap 44 and the exterior walls of the tube 4. Additional, or alternative, securing mechanisms may be used, including, but not limited to, adhesives, crimping, welding, staples, clips, or the like. In certain aspects, the cap 44 may be manufactured to be integrally formed with the tube Extending from shaft 48 of cap 44 are two or more, in certain aspects three or more, expandable arms 52. These arms 52 may be uniformly spaced about the perimeter of shaft 48 and are interchangeable between a contracted configuration (
The placement and orientation of the arms on the shaft 48 illustrated in the figures are not necessarily limiting to the invention. To this end, the arms may be oriented and/or placed in any position so as to effectuate the use of the invention discussed herein. In certain preferred aspects, the arms 52 should be a sufficient distance from the ends of the stent 6 such that the retention element, when expanded, will not interfere with stent 6 deployment or radial expansion. The arms should similarly be shaped, oriented, or placed on cap 44 such that they do not interfere with deployment of the stent. End 60 of each arm 52 may be provided within one or more extensions 62, which may be adapted to prevent or otherwise mitigate stent movement during stent deployment.
In certain non-limiting aspects, and to facilitate self-deployable conversion from the contracted position to the expanded position, the arms 52 may be pre-stressed, flat springs that are manufactured to maintain the expanded position illustrated in
The present invention is not limited to flat-spring arms. That is, arms 52 may be adapted into alternative configurations consistent with the teachings herein. To this end, any mechanism or spring type may be used to create a self-deployable cap 44 having the outward default position illustrated in
In certain preferred embodiments, and as illustrated in
The sheath may be removed in accordance with the teachings above such that the arms 52 are expanded first and the stent is expanded only after the arms 52 are in-place. In certain aspects, however, the sheath slides or is moved along the length of the catheter tube to facilitate conversion of cap 44 between the expanded and contracted positions. By way of non-limiting example, the sheath 68 may be retracted away from the stent deployment site by sliding it along the length of the catheter away from the implantation site, but maintaining it on the catheter tube during stent deployment. After the stent is secured within the patient, the sheath 68 may be slid back along the catheter tube to engage the arms 52 and convert them by collapsing them into a contracted position, as illustrated in
Referring to
The film 64 may be adapted to reduce or prevent fluid flow in and around the stent during stent implantation. To this end, the film 64 may be secured to the arms and shaft such that it reduces or prevents fluid flow between arms 52. It may be manufactured from a material having a relatively flexible modulus of elasticity that is able to withstand conversion between the contracted to expanded state of arms 52 and the force of the surrounding fluid within the vessel.
In certain aspects, the material, itself, is impermeable, or at least partially impermeable, to fluid flow through it. In certain aspects, the film 64 is entirely impermeable to fluid flow through it.
The flow of fluid in and around the film 64 may be controlled by one or a combination of elements associated with the film 64. In certain embodiments, expansion of the arms 52 and film 64 may be such that fluid flow is stopped beyond cap 44, particularly the point of widest diameter formed by arms 52 and film 64. In other embodiments, however, fluid may be reduced by one or a combination of features. In one embodiment, for example, fluid may be directed over the upper edge 66 of film 64 such that it flows through a space between the upper edge 66 of the film and the vessel wall. The fluid flow rate may be controlled based upon the size of the film 64. The smaller the film, the greater the distance between the upper edge 66 and the vessel wall and the faster the flow rate. Conversely, the longer the film, the less the distance between the upper edge 64 and the more the fluid flow rate is reduced.
As illustrated in
The film 64 can be manufactured from any biocompatible, and preferably flexible or semi-flexible material including, but not limited to, biocompatible polymeric materials, such as poly(ethylene terephthalate) (PET) or polytetrafluoroethylene (PTFE), or bioresorbable materials, such as levorotatory polylactic acid (L-PLA) or polyglycolic acid (PGA), or combinations thereof. In certain aspects, the film may be manufactured, at least in part, from a fiber reinforced material or a fiber-based material, such as silk, spider silk, or the like, or a cloth-based material such as cotton, polyesters, or the like. Such materials may be used alone or in combination with other polymeric materials provided herein, In further aspects, the material comprises a superelastic material that can withstand tight compression in a compacted configuration and expansion to a deployed configuration once released in place.
In one non-limiting embodiment, the film is manufactured, at least in part, from ePTFE or any similar polymeric material discussed herein or otherwise known in the art.
Holes 65 in the film 64 may be manufactured into the film 64 or otherwise artificially created during production or by the end user. In certain aspects, the film 64 may be formed from as a mesh of any or more of the foregoing materials wherein the holes or fenestrations are naturally created between the fibers used to form the mesh. Additional or alternative embodiments will be readily apparent to the skilled artisan on the basis of the disclosure herein. Cap 44, or any portion thereof, may be provided with one or a series of radiopaque markers, such as circumferential bands, along its length and/or at its ends or at various points along the shaft 48, arms 52, and/or film 64. Such elements, as discussed herein, could further facilitate fluoroscopic visualization of the catheter during deployment and ensure correct relative positioning of the assembly and/or of the stent.
In the embodiments above, the distal most retention element is illustrated as being cap 44. As illustrated in
To this end, and in certain embodiments, the present invention includes embodiments where the distal end retention element is the cap 44 and the proximal end retention element is expandable element 10, as illustrated in
In even further embodiments, the distal end includes cap 44 and the proximal end also include a cap-like element 71 in accordance with the above and as illustrated in
Once in place, the operator can then expand retention elements 44 and/or 10 (or 71 in
The sheath may be further retracted so as to uncover the stent and retention element 10 (or 71 in
Expansion of the retention elements 44 and 10 (or 71) are not necessarily limited to the order provided above. In certain aspects, for example, a sheath or multiple sheaths may be provided to independently controls the deployment of cap 44 such that it expands before, after, or simultaneously with retention element 10 (or 71).
The present invention is also not limited to the expansion of both retention elements 44 and 10 (or 71) during the deployment process. In further aspects, only one of the two retention elements is expanded, which may be based on the direction of blood flow and the insertion point of the device. By way of non-limiting example, the retention element most proximal to the handle can be expanded to prevent migration of the stent during stent deployment in an arterial vessel or to reduce/prevent fluid flow during deployment in a vein. Conversely, the retention element most distal to the handle can be expanded to prevent migration of the stent during the deployment in a vein or to reduce/prevent fluid flow during deployment in an artery.
In certain embodiments, it is desirable to expand the retention element prior to deployment of the stent. In such embodiments, the stent could be manually expanded using an angioplasty balloon or other deployment mechanism discussed herein or otherwise known in the art. In further embodiments, where a self-deployable stent is desirable, a second sheath may be used that covers only the stent. Once the sheath covering the retention elements is removed, the retention elements may be deployed in accordance with one of the embodiments herein and the stent deployed only after the retention element(s) are in place.
One of skill in the art would readily appreciate that determination of which retention element will be deployed or a time in which one or both retention elements will be deployed can be dependent upon a wide-array of the circumstances surrounding the deployment process. Such circumstances may include, but are not limited to, the type of vessel (e.g. artery or vein), the proximity of the vessel to the heart or a vital organ, the rate of fluid flow through the vessel, the size of the stent, or the like. To this end, the present invention is not limited to any particular rationale for expanding only one retention element or for temporally staggering the expansion of the two retention elements. Rather, the present invention includes the expansion of only one retention element or of both retention elements for any reason during the stent deployment process.
Regardless of which mechanism is used, after the stent is expanded the operator can then use the radiopaque markers to adjust the positioning of the stent 20, as necessary. The stent a can then be implanted, as discussed above. Once secured, the retention element 10, if used, is deflated by withdrawing the fluid through the lumen 18 (illustrated in
One advantage to the foregoing device, system, and method is that migration of the stent 20 is minimized during deployment without impacting implantation of the stent. The expansion of arms 52 substantially fill the inner lumen space of the blood vessel or artery with the film 64.
The film 64 prevents and/or reduces the amount of blow flowing through the vessel, thereby reducing the force exerted on the stent by the blood during deployment. The arms 52, particularly extensions 62, may also act as a fail-safe by physically preventing stent migration during deployment. This allows the operator to easily manipulate the stent 20, while minimizing the risk of stent 20 migration. This is particularly, though not exclusively, advantageous when the stent is being deployed in a vein or bodily conduit where fluid flows to a vital organ. In further embodiments, the assembly and methods are advantageous when a stent is desirable in a venous system, such as the deployment of such stents to maintain hemodialysis vascular access. In such instances, the stent can be implanted in accordance with the present invention with significantly lower risk of migration toward or into the heart.
Additional advantages and embodiments will be readily apparent to one of skill in the art, based on the disclosure provided herein.
This international patent application claims priority to U.S. provisional patent application Ser. No. 62/033,148, filed on 5 Aug. 2014, the teachings and entire disclosure of which are fully incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US15/43794 | 8/5/2015 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62033148 | Aug 2014 | US |
