1. Field of the Invention
This patent application for this invention relates to stent devices and their methods of use for treating cranial aneurysms. This non-provisional patent application is based upon Provisional Patent Application Ser. No. 60/753,764 filed Dec. 23, 2005, and upon Provisional Patent Application Ser. No. 60/755,639, filed December 2005, each of which are incorporated herein by reference.
2. Prior art
Current treatment of bifurcation aneurysms currently utilize balloons and a stent. However, such balloons may at least temporarily occlude blood flow through the vessels in which they are placed. Those balloons also need to be deflated and removed at the end of a vessel remodeling session. Such balloons may also rupture an aneurysm and/or a vessel when that balloon is inflated. Utilizing a stent with the balloon in a bifurcation aneurysm does not protect both of its efferent vessels. Such balloon vessel remodeling also requires two experienced surgeons and two catheters simultaneously, in a single vessel at the same time.
It is an object of the present invention to overcome the disadvantages of the prior art.
It is a further object of the present invention to provide a bifurcation aneurysm treatment which will allow proper blood flow during the treatment procedure, and to prevent reflux of any embolic agent placed within the aneurysm.
The present invention relates to an elongated aneurysm-treating stent device having an open proximal end, and an open distal end. The stent device is cylindrical and is preferably constructed from a woven pattern of metallic fibers. The proximal end of the stent device may have a plurality of radio opaque markers thereon. An elongated electrolytic tethering wire is arranged at several circumferential locations on the proximal end of the stent device. Those tethering wires join a common electrolytic tethering wire which extends through a delivery catheter. The tethering wires are attached to the proximal end of the stent device at electrolytic junctions. Those electrolytic junctions are arranged so as to be severed once the stent device has been put in place. The web design of the stent device is woven so as to have larger openings between the web fibers towards the distalmost end of the stent device.
A generally hemispherically-shaped “drip” chamber is fixably attached to the distalmost end of the stent device. The distalmost chamber has a floor section extending thereacross which effectively closes off the distal end of the stent device. The hemispherical chamber and the floor thereacross are entirely preferably radiopaque. The woven nature of the chamber provides smaller cell sizes between adjacent wires or fibers, comprising the chamber. Those cell or opening sizes within the chamber and the chamber floor are however, wide enough to admit a 0.014 or 0.010 microcatheter therethrough.
Both the drip chamber and the body of the stent device may be made of self-expanding metal, such as nitinol or expandable stainless steel or the like. Such material may also be plated with for example, a gold or platinum thereon. Such metal or plating also, may be porous, so as to carry and emit drugs therefrom, upon their delivery into a body vessel.
The body of the stent device as well as the drip chamber are expandable, for example from a 3 millimeter diameter to about a 10 millimeter diameter to permit it to fit within the parent vessel and also then to expand to nest within the aneurysm neck.
The stent device is arranged so that the weave of the fibrous metal adjacent its distalmost end expands more widely than that at a proximal position, so as to create and generate an outwardly tapered “waffle cone” shape, which would provide wide enough cell openings in the weave disposed between the efferent vessels for blood to flow therethrough. The diameter of the chamber floor at the proximal end of the drip chamber is designed so as to nestingly mate with the approximate diameter of the neck of the aneurysm itself. The drip chamber itself is arranged to expand to a diameter larger than the diameter of the neck of the aneurysm so as to permit a blocking nesting engagement therewith. The cell structure between the fibers of the woven drip chamber are smaller than the openings at the expanded distalmost end of the stent device itself. Those fibers are woven so as to effect such a trumpet or waffle cone shaped configuration to the distalmost third or quarter of the stent device. With such tapered expansion of those fibers, the open cell structure is inherently permitted to let blood pas therethrough, while also effecting the locking of the drip chamber within the neck of the aneurysm.
The introduction of an aneurysm treating stent device into an aneurysm is done by threading a microcatheter, bearing a micro wire, through the vasculature of the patient and into the bifurcation aneurysm. The microcatheter or sheath surrounding the microwire is pulled proximally, so as to leave the bare microware juxtaposed within the aneurysm itself. A catheter with a waffle cone stent device loaded therewithin is threaded over the microwire and that catheter is advanced into the aneurysm through the parent vessel thereadjacent. The microwire or guidewire is then removed by its withdrawal proximally through the delivery catheter. The waffle cone stent device with its attendant distalmost drip chamber thereon, in its unexpanded state, is guided through that parent vessel with the drip chamber disposed nestingly at the neck of the aneurysm. Withdrawal of the delivery catheter from the outside of the waffle cone stent and drip chamber would permit their respective self-expansion to occur. Adjustments in the position of the drip chamber and the waffle cone stent device may be made by the tethering wire which is attached to the proximal most end of the stent device. Once the stent device and drip chamber are properly placed, the tethering wire may be electronically separated from the proximal end of the stent device.
Upon withdrawal of the delivery stent from the drip chamber portions of the stent device, an arrangement of folded struts may flare out to their own spring tension or self-expansion capabilities, to permit the drip chamber to be firmly anchored within the neck confines of the aneurysm.
A new microcatheter or guidewire may be advanced through the waffle cone stent and drip chamber after it has been placed. That microwire or guide wire would be arranged so as to extend through one of the open cells in the floor of the drip chamber and also through the outer cells of the drip chamber as well. A further new microcatheter would then be threaded over that microwire or guidewire which extends distally beyond the drip chamber. Once that new microcatheter is in place distally beyond the distalmost end of the drip chamber, that microwire or guidewire is withdrawn proximally therefrom.
The microcatheter then acts as an ejector, through which Onyx™, an embolic agent, which is injected into the aneurysm itself. The dome of the drip chamber having small cellular openings therein, acts as a protective shield to prevent the Onyx from reflux into the parent vessel adjacent the aneurysm. Once the Onyx embolic agent has filled the fundus of the aneurysm, that delivery catheter is removed. A further microwire or guidewire may then be inserted through the stent device and into the drip chamber through its floor. That microwire or guidewire would then be removed and the drip chamber itself filled with a second material, such as a more viscous Onyx, metallic coils, or for example a nitinol plug. Once the drip chamber is filled with the second embolic material, that drip chamber will block the original onyx from entering the parent vessel.
The microcatheters and electrolytic tether wires may then be removed from the stent device and the aneurysm remains filled with multiple embolic material, now generally harmless to the patient.
The invention thus comprises a vascular aneurysm treating stent arrangement having a proximal end and a distal end, the stent being formed of a differentially expandable material, wherein the distal end is deformably expandable to a cone shape, and a deformable enclosed chamber arranged on the distal end of the stent. The deformable chamber preferably has an expandable foraminous floor arranged thereon. The chamber preferably has wall portions with a smaller opening pattern arranged therethrough. The stent device is preferably comprised of a woven material. The stent preferably has a severable tether arranged in its proximal end.
The invention also comprises a method of treating a bifurcated aneurysm having a neck portion, into a body vessel, comprising one or more of the following steps: introducing a stent assembly into the body vessel, the stent having a body portion and a distal chamber on the body portion; inserting the chamber into the aneurysm; expanding the chamber to a known dimension and volume; introducing a first delivery catheter through the body portion of the stent and through the chamber and into the aneurysm; injecting an first embolic material into the aneurysm; removing the first delivery catheter from the aneurysm and introducing a second delivery catheter through the body portion of the stent and into the chamber; injecting a known quantity of a second embolic material into the chamber, completely filling the chamber; nesting the chamber within the neck portion of the aneurysm; opening a strut arrangement into the aneurysm to secure the chamber within the aneurysm; placing a floor in a proximal portion of the chamber to segregate the second embolic material from the body vessel; expanding a distal portion of the stent body into a cone shape; expanding the chamber into a known volume within the aneurysm simultaneously with the expansion of the stent body.
The invention may also comprise a vascular aneurysm treating stent arrangement having a proximal end and a distal end, the distal end having a larger pattern of openings therethrough than any sidewall openings at the proximal end, upon delivery thereof. The distal end of the stent preferably has an expandable web floor disposed thereacross, the floor having an expandable dome-like chamber thereon to permit a first embolytic material to be disposed outwardly thereof, and a second embolytic material to be separately retained within the dome-like chamber. The second material preferably comprises metal coils. The second material in the chamber preferably comprises a blocking component to the first embolytic material. The distal end of the stent has enlarged openings thereacross to permit blood flow across the distal end of the stent, and the distal end of the stent has an expandable, aneurysm-nesting chamber thereon to anchor the stent thereat. The distal end of the stent preferably includes a plurality or articulable struts arranged to spread radially outwardly radially adjacent the expandable chamber to further anchor the stent within the aneurysm.
The objects and advantages of the present invention will become more apparent when viewed in conjunction with the following drawings, in which:
Referring now to the drawings in detail, and particularly to
A generally hemispherically-shaped “drip” chamber 50 is fixably attached to the distalmost end of the stent device 20, as shown in
Both the drip chamber 50, the chamber floor 52 and the body of the stent device 20 may be made of self-expanding memory metal, such as nitinol or expandable stainless steel or the like. Such material may also be plated with for example, a gold or platinum thereon. Such metal or plating also, may be porous, so as to carry, be re-supplied with (by subsequent re-coating with a separate drug delivery catheter) and to emit drugs therefrom, upon their delivery into a body vessel.
The body of the stent device 20 as well as the drip chamber 50 are expandable, as is represented in
The stent device 20 is arranged so that the weave of the fibrous metal adjacent its distalmost end expands more widely than that at a proximal position of the stent device 20, so as to create and generate an outwardly tapered “waffle cone” shape 63. Such distal conical expansion, for example, going from 3 mm to 10 mm, depending upon where it is constrained within the parent vessel and then expands in the aneurysm neck, the stent 20 would provide wide enough distally-enlarged cell openings in the weave disposed between the efferent vessels 66 for facilitating the blood “B” to flow therethrough. Such expansion is represented in
The introduction of an aneurysm treating stent device 20 into an aneurysm is done by threading a microcatheter or sheath 70, bearing a micro wire 72, through the vasculature 58 of the patient and into the bifurcation aneurysm 62, as is represented in
Upon withdrawal of the delivery stent from the drip chamber portions of the stent device 20, in a further preferred embodiment thereof, an arrangement of folded struts 80, shown in
A new microcatheter or guidewire 82 may be advanced through the waffle cone stent 20 and drip chamber 50 after they has been properly placed within the aneurysm 62, as represented in
The microcatheter 86 has a distal orifice 87 which then acts as an ejector, through which Onyx™, an embolic agent 88, may be introduced into the aneurysm 62. The dome of the drip chamber 50 having small cellular openings 54 therein, acts as a protective shield to prevent the Onyx 88 from reflux into the parent vessel 58 adjacent the aneurysm 62. Once the Onyx embolic agent 88 has filled the fundus of the aneurysm 62, that delivery catheter 86 is removed. A further microwire or guidewire may then be inserted through the stent device 20 and into the drip chamber 50 through its floor 52. That microwire or guidewire would then be removed and the drip chamber 50 being of a predetermined known volume, may be completely filled with a predetermined amount of a second embolic material, such as a more viscous Onyx, metallic coils, or for example a nitinol plug. The predetermined amount of embolic material thus leaves no voids within the drip chamber 50, minimizing the likelihood of leakage of the initial embolic material into the parent vessel and prevents any undesired collapse or folding of that chamber 50. Once the drip chamber 50 is filled with the second embolic material 91, that drip chamber 50 will thus block the original onyx 88 from entering the parent vessel 58, as represented in
The microcatheters 93 and electrolytic tether wires 95 representatively shown in
Number | Date | Country | |
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60753764 | Dec 2005 | US | |
60755639 | Dec 2005 | US |