WO2008157507A2

WO2008157507A2 - Blood flow diverters and aneurysm covering devices

Info

Publication number: WO2008157507A2
Application number: PCT/US2008/067139
Authority: WO
Inventors: Brian B. Martin; Martin S. Dieck; Charles L. Euteneuer; Andrew T. Schieber
Original assignee: Nfocus Neuromedical, Inc.
Priority date: 2007-06-15
Filing date: 2008-06-16
Publication date: 2008-12-24
Also published as: WO2008157507A3

Abstract

The implant devices have a single-layer wire braid tube that is heat set into a double-layer cover, shaped as a concave disc or a curved rectangle. In one variation, the device is deliverable as the single-layer tube in a delivery sheath and assumes the double-layer configuration upon release from the sheath. Delivery may alternatively be accomplished using polymer fibers interwoven in the braid, the ends of which are held by a delivery guide and melted to release the cover at the target site. The device can have an alignment wire extending from the cover to align the device at the aneurysm. Single layer braid covers with alignment wires, also deliverable using meltable polymer fibers, are contemplated.

Description

BLOOD FLOW DIVERTERS AND ANEURYSM COVERING DEVICES

Inventors: Brian B. Martin, Martin S. Dieck, Maria Aboytes, Charles L. Euteneuer, Andrew T. Schieber

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a Continuation-in-Part application of U.S. Serial No. 11/840,679 filed August 17, 2007 which claims priority to U.S. Provisional Application No. 60/822,741 filed on August 17, 2006 both entitled ANEURYSM COVERING DEVICES AND DELIVERY DEVICES, inventors Martin Dieck, Maria Aboytes, and Brian Martin. This application also claims priority to U.S. Provisional Application No. 60/929,179 filed on June 15, 2007 entitled BLOOD FLOW DIVERTER, inventors Charles Euteneuer and Andrew Schieber. All of the above applications are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

[0002] The term aneurysm refers to any localized widening or outpouching of an artery, a vein, or the heart. All aneurysms are potentially dangerous since the wall of the dilated portion of the involved vessel can become weakened and may possibly rupture.

[0003] A common type of aneurysm is a brain aneurysm. Brain aneurysms are widened areas of arteries or veins within the brain itself. These may be caused by head injury, an inherited (congenital) malformation of the vessels, high blood pressure, or atherosclerosis. A common type of brain aneurysm is known as a berry aneurysm. Berry aneurysms are small, berry-shaped outpouchings of the main arteries that supply the brain and are particularly dangerous since they are susceptible to rupture, leading to often fatal bleeding within the brain. Brain aneurysms can occur at any age but are more common in adults than in children. [0004] Cerebral vascular aneurysms are currently treated using surgical clips via open craniotomy or by filling the aneurysm with coils using endovascular techniques. In order for aneurysms to be treated surgically they must be in a location where access is possible and they must be of a type that lends itself to clipping. Not all aneurysms which can be accessed can be clipped due to anatomical considerations. Likewise for aneurysms to be coiled they too must meet certain criteria with respect to geometry and location. The dome and neck must be such that coils placed in the dome, stay in place, do not protrude out into the artery causing turbulence or occlusion, and cause thrombosis of the blood in the aneurysm. Even with successful initial coiling it is still possible for clotted blood within the aneurysm to lyse over time thereby subjecting the wall to pressure and placing the aneurysm at risk of rupture.

[0005] Research has been done looking at blood flow into aneurysms and the effect flow has on blood's ability to clot. Research suggests that not all flow need to be stopped from entering into an aneurysm for it to occlude and that having a structure which is about 40% open will still divert flow sufficient to cause thrombosis in the sack. A study done at the Cleveland Clinic showed that stent assisted coiling as compared to coils only significantly reduces recanalization rates. This work leads us to believe there could still be a better method than coiling or clipping to treat cerebral aneurysms by diverting flow past the aneurysm neck. [0006] A variety of devices have been developed to cover such aneurysms, including stentlike devices having a one-sided covering or patch to cover the opening of the aneurysm along the blood vessel. However, such devices are often difficult to construct and deploy. In particular, these one-sided coverings need to be correctly oriented and deployed so as to cover the aneurysm opening. This is challenging in that the vascular anatomy preceding most aneurysms is very tortuous and long and therefore difficult to control and transmit torque for precise delivery. Therefore, improved devices for treatment of aneurysms are desired along with improved delivery devices and methods. At least some of these objectives will be met by the present invention.

SUMMARY OF THE INVENTION

[0007] The description, objects and advantages of the present invention will become apparent from the detailed description to follow, together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figs. 1 A-1 E illustrate an embodiment of a covering device along with an example of its manufacture.

[0009] Fig. 2A illustrates a blood vessel having a berry aneurysm. [0010] Fig. 2B illustrates a covering positioned with the blood vessel of Fig. 2A so that the covering covers the opening of the aneurysm. [0011] Fig. 2C-2D illustrates a delivery system having a fill tube coupled with the covering device.

[0012] Fig. 3 illustrates another embodiment of a covering device of the present invention.

[0013] Figs. 4A-4B illustrate a covering device having an oval shaped covering. [0014] Figs. 5-7 illustrate alternative embodiments having coverings of different shapes and sizes.

[0015] Fig. 8 illustrates an embodiment of a covering having a diamond shape with joints.

[0016] Fig. 9 illustrates an embodiment of a covering device having a covering attached to two rings, each by a coaxial strut.

[0017] Figs. 10A-10B illustrates an embodiment of a covering device having a covering attached to each ring by a curved strut.

[0018] Figs. 11 A-11 D illustrates an embodiment of a covering device including two rings having a C-shape, wherein each ring is connected to two struts which are coupled to the covering at a common location.

[0019] Fig. 12 illustrates some example features which may be included in a covering.

[0020] Fig. 13 illustrates a variety of methods for providing radiopacity [0021] Fig. 14 illustrates an example of device material having radiopaque material incorporated therein.

[0022] Fig. 15 illustrates an embodiment of a covering device constructed from mesh or a cut tube stent and a covering formed from a flexible material. [0023] Fig. 16 illustrates a method of joining two materials. [0024] Fig. 17 illustrates a covering positioned within a bifurcated blood vessel so that the covering covers the aneurysm. [0025] Figs. 18A- 18B illustrates a push-style delivery system. [0026] Fig. 19 illustrates a pull-style delivery system. [0027] Figs. 20A-20C illustrates a sheath-style delivery system.

[0028] Fig. 21 illustrates the positioning of a guidewire within an aneurysm in a blood vessel.

[0029] Fig. 22 illustrates a sheath-style delivery system having a force conversion mechanism.

[0030] Fig. 23A-23B illustrates an embodiment of a force conversion mechanism.

[0031] Fig. 24 illustrates another embodiment of a force conversion mechanism.

[0032] Figs. 25A-25D illustrate an embodiment of a delivery system which provides for rotation of the covering device with the use of a pulley.

[0033] Fig. 26 illustrates another embodiment of a pulley.

[0034] Figs. 27A-27C illustrate an embodiment of a delivery system which provides for rotation of the covering device with the use of a threaded portion.

[0035] Figs. 28A-28B illustrate a disc-shaped double-braid cover in place at an aneurysm.

[0036] Fig. 29A illustrates delivery of a disc-shaped double-braid cover from the distal end of a catheter. Fig. 29B illustrates delivery of a disc-shaped cover on a delivery sheath using a side port and guidewire.

[0037] Fig. 3OA shows complete delivery of a disc-shaped double-braid cover from a side port of a delivery tube, the tube stabilized by a distal balloon. Fig. 3OB shows delivery of a disc-shaped cover from the distal end of a delivery catheter using a guidewire.

[0038] Fig. 31 A-31 E depict various forms of the tubular braid as it is formed into a cover, which is depicted in Fig. 31 C, 31 D, and 31 E.

[0039] Fig. 32A and 32B depict the tubular braid formed in a double-braid rectangular shown in Figs. 31 A-31 E delivered to a vessel.

[0040] Fig, 33A and 33B depict an embodiment having polymer fibers for connecting to a delivery guide.

[0041] Fig. 34A-34D depict a wire alignment guide for positioning a cover at an aneurysm opening.

DETAILED DESCRIPTION OF THE INVENTION [0042] A variety of covering devices are provided which may be used to treat an aneurysm, particularly a berry aneurysm. One embodiment of such a covering device, along with an example of its manufacture, is illustrated in Figs. 1 A-1 E. In this embodiment, the device is laser cut from a sheet 10 of material. Example materials include nitinol, stainless steel, cobalt, chromium, and tantalum, to name a few. Fig. 1A illustrates such a sheet 10 of material. Fig. 1B illustrates an example cutout 12 from the sheet 10. In this embodiment, the cutout 12 includes rings 14, struts 16 and a covering 18. The rings 14 and/or struts 16 may vary in length to allow for improved delivery and final stability. The covering 18 may be solid or split to facilitate folding and delivery. In other embodiments, the covering 18 comprises a scaffold, such as a ring or hoop, which is covered by ePTFE or an elastic material or metal or the covering 18 is not cut from the sheet 10 and is added in a later step of the manufacture. Further, optional bands 20 may be added to encourage expansion in a curved direction. The bands 20 may be made of plastic and may be flexible but become tight against the force of expansion contributing to the expansion in a curved direction. Also, struts 16 may optionally be coated with a polymer to reduce friction during delivery. [0043] Referring to Fig. 1C, the cutout 12 is then mounted on a shaping device 22, such as a cylinder or mandrel. Fig. 1D illustrates a cross-section of Fig. 1 C. The cutout 12 is then set in this shape, such as by the application of heat and by bending over the shaping device 22, to form the covering device 24. Fig. 1 E illustrates the covering device 24 removed from the shaping device 22. [0044] Such construction of the device 24 from a flat sheet 10 provides significant advances in manufacturability. This is due to the ease in which a machining process can be conducted in two dimensions compared to three dimensions. However, it may be appreciated that the covering device 24 may alternatively be constructed from a tube or from shaped wire, for example. [0045] Fig. 2A illustrates a blood vessel V having a berry aneurysm A. Blood is shown flowing through the vessel V and into the aneurysm A. Fig. 2B illustrates the covering device 24 of Fig. 1 E positioned within the blood vessel V so that the covering 18 covers the opening the aneurysm A. The rings 14 hold the device 24 in place within the vessel V. Thus, 10 blood flows flowing through the vessel V passes undisturbed through the rings 14 and is blocked from entering the aneurysm A by the covering 18. In some embodiments, the device 24 includes one or more alignment elements, such as a radiopaque filament 26, to determine when the covering 18 is desirably aligned over the aneurysm A. Such alignment may be detected by monitoring the radiopaque filament 26 until it is within the aneurysm A. Other 15 examples of alignment elements include a balloon, which may be inflated into the aneurysm A when desirably aligned, or a fluid port which passes fluid into the aneurysm A when desirably aligned. [0046] Fig. 3 illustrates another embodiment of a covering device 24 of the present invention. In this embodiment, the number of struts 16 has been minimized to allow for easier delivery. In addition, the rings 14 are C-shaped rather than circular shaped. Figs. 4A- 4B illustrate a similar embodiment. In this embodiment, the device 24 has an oval shaped covering 18, as illustrated in Fig. 4A. Fig. 4B provides a side view of the device 24 of Fig. 4A. In this embodiment, the device 24 includes an additional ring 14' positioned at or near the covering 18 for added stability near the aneurysm. Such a ring 14' may optionally be 25 formed from wire or ribbon material. Figs. 5-7 illustrate alternative embodiments having coverings 18 of different shapes and sizes such as a large oval shape (Fig. 5), a rounded rectangular shape (Fig. 6) and a square shape (Fig. 7). The shape of the covering 18 may be chosen based on a variety of factors, including ease of manufacture or anatomy of the aneurysm, to name a few. [0047] Fig. 8 illustrates another embodiment of the covering device 24. In this embodiment, the covering 18 has a diamond shape. In addition, the device 24 includes a plurality of flexible areas or joints 30, 30'. Joint 30 is shown on a ring 14 and allows flexing or folding of the ring 14. In this embodiment, the joint 30 is formed by joining two discontinuous portions of the ring 14 with a flexible material 32, such as a flexible overtube or elastic. Alternatively, the flexible material 32 may extend along an inside or outside surface of the ring, or a combination of these. A similar joint 30' is shown on the covering 18. Such joints 30,30' may improve ease of delivery. Such joints 30,30' may be used on any of the embodiments of the covering device 24.

[0048] Fig. 9 illustrates another embodiment of a covering device 24. In this embodiment, the device 24 comprises a covering 18 attached to two rings 14, each by a coaxial strut 16. Fig. 10A illustrates a similar embodiment of a covering device 24. Here covering 18 is attached to each ring 14 by a curved strut 16. In addition, the device 24 includes an embodiment of a strain relief mechanism, illustrated in Fig. 1OB. As shown, the core 15 tapers and is covered by a softer material 17 so as to maintain the outer diameter. The core 15 may also be one piece with free ends protected by the strain relief mechanism. [0049] Fig. 11 A illustrates another embodiment of a covering device 24. Here the device 24 includes two rings 14 having a C-shape, wherein each ring 14 is connected to two struts 16, 16' which are coupled to the covering 18 at a common location 34. Fig. 11 B illustrates one embodiment of the device 24 of Fig. 11 A in a deployed position. Here, the struts 16, 16' (hidden) fold under the covering 18 so that the rings 14 are drawn together under the covering 18. This may allow positioning of the device 24 in blood vessels having minimal space around the aneurysm conducive to anchoring the device 24. Fig. 11 C shows a top view of the deployed device 24 wherein the rings 14 only extend a short distance from the covering 18. It may be appreciated that in some embodiments the covering 18 entirely cover the rings 14 when in the deployed position. Fig. 11 D shows an alternative deployed position of the device of Fig. 11 A. Here, the rings 14 tilt inwards, underneath the covering 18.

[0050] Fig. 12 illustrates some example features which may be included in the covering 18. For example, a slit 40 may be formed by overlapping material. This provides for better folding flexibility and leaves a closed surface once the covering 18 is deployed. If the covering 18 is formed from a scaffold, such as a nitinol hoop, with a flexible covering, such as ePTFE, the scaffold may be coated with a material, such as FEP. The material may be dashed for better folding and flexibility. If the covering 18 is formed from a metal or alloy, the covering 18 may be etched so that the covering 18 is thicker near its edges and thinner near its center.

[0051] In some embodiments, the covering device 24 provides radiopacity to assist in desired placement of the device 24 within a blood vessel. Any portion of the device 24 may be radiopaque. Fig. 13 illustrates a variety of methods for providing such radiopacity. For example, a radiopaque agent may be deposited in cut channels in the device 24. A radiopaque agent may be chemical, sputtered or ion deposited on the device 24. A radiopaque agent may be incorporated into the device material, woven through the device material, or crimped on the outside of the device material. In some embodiments, the device material is comprised of a "drawn filled tube" (DFT) filled with, for example, gold, or platinum, platinum- iridium.

[0052] Fig. 14 illustrates an example of device material having radiopaque material incorporated therein. As shown, a sheet 40 of radiopaque material, such as gold, is sandwiched between two sheets 10, 10' of material, such as nitinol, stainless steel, tantalum, Co-Cr, or other alloy. The sheets 10, 41 , 10' are joined together to form a laminate 43, such as with welds or pins 45. The covering device 24 is then cutout from the laminate 43 and formed into three dimensions such as described above.

[0053] Fig. 15 illustrates an embodiment of a covering device 24 constructed from mesh or a cut tube stent and a covering 18 formed from a flexible material, such as FEP, PTFE, ePTFE, nylon, polyurethane, Tecoflex, Pebax, polyester, PET, Hytrel, to name a few. The covering 18 is adhered to the mesh by using an appropriate weld.

[0054] In some embodiments, it may be desired to have some components elastic and some inelastic. It is often the case that these materials cannot be easily connected. Fig. 16 illustrates a method where two such materials can be joined by way of a mechanical fit and then sealed by a pressure fit of a material constraining the surface and keeping the dissimilar pieces locked in position relative to each other. For example, roughening and/or holes may allow for a better hold on each material by increasing friction or flowing into a channel and locking. This is only an example and many others are possible with a similar objective.

[0055] It may be appreciated that the covering device 24 may be used to treat aneurysms in a variety of locations. Often, cerebral berry aneurysms are located at bifurcations of blood vessels. The covering devices 24 described herein may be used to treat such aneurysms. Fig. 17 illustrates a covering 24 positioned within a bifurcated blood vessel V so that the covering 18 covers the aneurysm A. [0056] A variety of delivery devices may be used to deliver the covering devices 24 of the present invention. For example, Figs. 18A- 18B illustrate a push-style delivery system. In this embodiment, the delivery system comprises a catheter 50 having a lumen 52 and a push- rod 54 extending through the lumen 52. The covering device 24 is loaded within the lumen 52 near the distal end of the catheter 50. The catheter 50 is then advanced through the vasculature to a target delivery site within a blood vessel V. The covering device 24 is then deployed at the target delivery site by advancing the push-rod 54 which pushes the device 24 out of the lumen 52 and into the blood vessel V. Typically, the device 24 is deployed so that a first ring 14 is disposed on one side of an aneurysm A and a second ring 14' is disposed on the other side of the aneurysm A, as illustrated in Fig. 18B. [0057] Fig. 19 illustrates a pull-style delivery system. In this embodiment, the delivery system comprises a catheter 60 having a lumen 62 and a pull element 64 extending through the lumen 52. The covering device 24 is loaded within the lumen 62 near the distal end of the catheter 60 and attached to the pull element 64. The catheter 60 is then advanced through the vasculature to a target delivery site within a blood vessel. The covering device 24 is then deployed at the target delivery site by advancing the pull element 64 which pulls the device 24 out of the lumen 52 and into the blood vessel V. Typically, the device 24 is deployed so that a first ring 14 is disposed on one side of an aneurysm A and a second ring 14' is disposed on the other side of the aneurysm A, such as illustrated in Fig. 18B. It may be appreciated that the pull element 64 may alternatively extend along the exterior of the catheter 60 or through a lumen in the wall of the catheter 60. [0058] Figs. 20A-20C illustrate a sheath-style delivery system. In this embodiment, the delivery system comprises a rod 66 positionable within a sheath 68. The covering device 24 is mountable on the rod 66 and the sheath 68 is extendable over the covering device 24, as illustrated in Fig. 2OA. The system is then advanced so that the covering 18 of the device 24 is positioned with a blood vessel V so as to cover an aneurysm A. In this embodiment, the rod 66 includes radiopaque markers 70 so assist in such positioning. The sheath 68 is then retracted, as illustrated in Fig. 2OB, releasing covering device 24 within the blood vessel V. Once the device 24 is deployed, as illustrated in Fig. 2OC, the rod 66 may then be retracted leaving the device 24 in place.

[0059] In some embodiments, the delivery system may be guided to the desired target location within the blood vessel with the use of a guidewire. Fig. 21 illustrates the positioning of a guidewire 72 within an aneurysm A in a blood vessel V. The delivery system, such as the push-style delivery system described above, includes a guide 74 that is used to track over the guidewire 72 to the target location. In this example, the guide 74 comprises a loop that is mounted on the catheter 50. Once the catheter 50 is positioned at the target location, the device 24 is deployed as described above. It may be appreciated that a guide 74 may be used with any delivery system.

[0060] In some embodiments, the delivery system provides for adjustment of the orientation of the covering device 24 to assist in desired covering of the aneurysm A. In particular, the delivery system provides for rotation of the covering device 24 within the blood vessel V so as to desirably align the covering 18 with the aneurysm A. Typically, such rotation is challenging because the vascular anatomy preceding most intracranial aneurysms is tortuous and long and therefore difficult to control and transmit torque for precise delivery. However, the present invention provides a variety of mechanisms for transforming longitudinal forces to rotational forces. This is desirable since longitudinal forces are often easier to transmit over long distances and through curves, or may be more precise than rotational forces. Example longitudinal forces include pull or push forces from an actuator wire, fiber, braid or other element to move, for example, piston gears to create a rotational step. Alternatively, pressure from hydraulic or gas forces may be converted to move a piston. Actual rotation occurs over a much shorter distance and may be ratcheted for easier control. It may be appreciated that the delivery systems described herein may be used to deliver a variety of devices and are not limited to the delivery of covering devices. In particular, the delivery systems which provide for rotation of the covering device may be used to deliver any device which may benefit from rotation or adjustment of orientation. [0061] An example of such a delivery system is illustrated in Fig. 22 and Figs. 23A-23B. Fig. 22 illustrates a sheath-style delivery system similar to Figs. 20A- 2OC. Here, the delivery system comprises a rod 66 positionable within a sheath 68. The rod 66 includes a proximal end 200, a force conversion mechanism 202 and a coupling device 204. The covering device 24 is mountable on the coupling device 204 and the sheath 68 is extendable over the rod 66 and covering device 24. The system is then advanced so that the covering 18 of the device 24 is positioned within a blood vessel V. The force conversion mechanism 202 converts longitudinal force applied to the proximal end 200 of the rod 66 to rotational force applied to the coupling device 204 so as to rotate the deliverable device. Figs. 23A-23B illustrate an embodiment the force conversion mechanism 202. Here, the mechanism 202 comprises a piston 206, a spring 208, a proximal rotor 210 having teeth 212 and a distal rotor 214 having angled teeth 216. The proximal rotor 210 and distal rotor 214 are held apart by the spring 208. Applying longitudinal force to the piston 206, compresses the spring 208 drawing the rotors 210, 212 together. The teeth 212 of the proximal rotor 210 engage the angled teeth 216 of the distal rotor 214 causing the distal rotor 212 to rotate. Each time the piston 206 and proximal rotor 210 are translated to engage the distal rotor 212, the distal rotor 212 turns one tooth dimension. The amount of distal rotation, therefore, can be selectively controlled by design of the gear teeth and the number of actuations engaged. In this embodiment, the distal rotor 214 is joined with or forms the coupling device 204 so as to rotate the covering 18 to cover an aneurysm A. The sheath 68 is then retracted, releasing covering device 24 within the blood vessel V. [0062] Fig. 24 illustrates another embodiment of a force conversion mechanism 202. Here, the mechanism 202 comprises a piston 206 having a barbell end 206a, a spring 208, a proximal rotor 210 and a distal rotor 214. The distal rotor 214 has internal ridges 220 having a curved or slanted orientation around the inner circumference. The piston 206 passes through the rotors 210,214 and spring 208 so that the barbell end 206a is disposed between a pair of ridges 220. Longitudinal force applied to the piston 206 pushes the barbell end 206a along the ridges 220. The slant of the ridges 220, rotates the distal rotor 214. The barbell end 206 eventually extends beyond the ridges 220. Once the piston 206 is released, the spring 208 draws the piston 206 back between an adjacent set of ridges 220 in the new rotated position. This can be repeated to further rotate the distal rotor 214.

[0063] Figs. 25A-25D illustrate an embodiment of a delivery system 90 which provides for rotation of the covering device 24. In this embodiment, as shown in Fig. 25A₁ the delivery system 90 includes a force conversion mechanism 92 which is attached or coupled with a coupling device which is removably coupleable with the covering device 24. The force conversion mechanism 92 comprises a pulley 94 which is rotated with the use of two tension wires 96, 96'. Referring to Fig. 25B, one tension wire 96 is wrapped around the pulley 94 in a clockwise direction and the other tension wire 96' is wrapped around the pulley 94 in a counterclockwise direction. Typically the force conversion mechanism 92 is disposed within a catheter 98 or similar elongate delivery device so as to be removably coupled with the covering device 24 which is deployable therefrom. Therefore, at least a portion of the force conversion mechanism 92 is disposed near a distal end 99 of the catheter 98. Each of the wires 96, 96' extend along the length of the catheter 98, optionally within individual lumens. Pulling or applying longitudinal force to one tension wire 96 causes the pulley 94 and therefore the covering device 24 to rotate in a counterclockwise direction, as shown in Fig. 25C. And, pulling or applying longitudinal force to the other tension wire 96' causes pulley 94 and therefore the covering device 24 to rotate in a clockwise direction, as shown in Fig. 25D. The wires 96,96' may be wrapped around a common portion of the pulley 94, as illustrated in Figs. 25A-25D, or each wire may be wrapped around a separate portion of the pulley, as illustrated in Fig. 26.

[0064] Figs. 27A-27C illustrate another embodiment of a delivery system 90 which provides for rotation of the covering device 24. In this embodiment, as shown in Fig. 27A, the delivery system 90 comprises a catheter 100 or similar elongate delivery device having a coupling member 102 near its distal end 104 which is configured to be removably coupled with the covering device 24. The coupling member 102 is connected with a force conversion mechanism comprising an elongate shaft 106 which is longitudinally translatable within the catheter 100. Such translation is achieved by rotating a knob 1 10 near the proximal end 112 of the catheter 100. Fig. 27B illustrates the proximal end 1 12 of the catheter 100. As shown, the knob 1 10 has a threaded interior which mates with a threaded portion 105 of the shaft 106. Thus, rotation of the knob 110 causes translation of the shaft 106. Fig. 27C illustrates the distal end 104 of the catheter 100. The coupling member 102 is shown coupled with the covering device 24. The coupling member 102 is also connected with a twisted shaped portion 114 of the shaft 106 via a shaped register 116. In this embodiment, the twisted shaped portion 114 comprises a twisted square portion and the shaped register 116 comprises a square register. However, any shape, such a triangle, rectangle, star, etc., which mates with purchase may be used. As the shaft 106 is translated in a distal direction, the twisted shaped portion 114 is advanced through the shaped register 116. The twisted configuration of the twisted shaped portion 114 rotates the square register 116 which in turn rotates the coupling member 102 and covering device 24. The covering device 24 may be rotated in the opposite direction by rotation the knob 110 in the opposite direction.

[0065] The rotational aspects of the delivery systems of the present invention assist in positioning the covering 18 of the covering device 24 over the neck of the aneurysm so as to block flow into the aneurysm. Additional features may also be used to assist in desired positioning of the covering 18. For example, Figs. 2C-2D illustrate a delivery system 120 having a fill tube 122 which couples with the covering device 24. In this embodiment, the fill tube 120 couples with a port 124 through the covering 18 so that fluid 126 flowing through the fill tube 120 passes through the port 124. Referring to Fig. 2C, when the covering 18 is aligned with an aneurysm A so that the aneurysm A is desirably isolated from the blood vessel V, fluid 126 flowing through the fill tube 120 will fill the aneurysm A. By using a radiopaque fluid 126, such filling of the aneurysm A may be visualized, thus verifying that the covering device 24 is desirably placed. If the covering device 24 is improperly placed, such that the aneurysm A is not sufficiently isolated, the fluid 126 will extravisate from the aneurysm A, as illustrated in Fig. 2D. The covering device 24 may then be repositioned until desirably placed. [0066] An aneurysm cover of double-layered braid shaped as a disc or rectangle is of sufficient braid density to occlude an aneurysm, if not initially, over a short period of time (e.g., 10-15 minutes as thrombosis within the aneurysm is allowed to develop. The braid can be of metal wire, including some radiopaque wire if desired. The metal wire can be NiTi alloy that is superelastic at room (or at least body) temperature. A single-layer tube of braid is formed either into a double-layer braid concave disc or a double-layer braid curved rectangle. The double-layer shape is heat set. After heat setting, the device can return to its single-layer state. Optionally, polymer strands are interlaced within the braid for use in a delivery system to provide attachment to a pusher or guide. Upon application of heat to the polymer strands, the polymer melts and releases the cover from the pusher/guide. The cover is typically loaded into a delivery sheath in its single layer tubular configuration, set over the guide. Upon release from the delivery sheath, the cover assumes its double-layer configuration. The disc or rectangular cover can further comprise a wire loop extending from it for aligning the cover at the opening of an aneurysm. The wire can be any metal or polymer filament, optimally NiTi alloy, or a radiopaque metal. [0067] In both the disc and rectangle configurations, the braid material is designed to minimally provide about 40% occlusion of blood flow to the aneurysm, and thus optimally is at least about 60% dense in its double-layer configuration. Greater than 60% density diverts flow sufficiently in the aneurysm sack to the point that thrombus forms. The approximate 60% density is achievable in the double- braid configuration depending on the specifications of the single layer preform braid.

[0068] The single-layer braid can be made of various PIC (per inch crossings) counts and wire diameters in order to obtain the correct density, flexibility, and radial force desired for the final double-layered cover. The diameter of the wire used in the braid can be from about 0.001 inches to about 0.005 inches. Depending on requirements of delivery system size, vessel size, braid density, and force requirements other wire diameters can also be used. For example, the tubular braid can be NiTi alloy wire braid as available through a variety of vendors (e.g., Secant Medical, Inc.). Braid having, e.g., 48, 96 or 144 wires can be used. Braid tube diameters ranging from 2mm to 5mm may be employed to achieve partial vessel coverage.

[0069] Furthermore, the braid can be coated with drugs to promote healing, reduce thrombogenecity, or to achieve any other desired biologic effect. The braid may be coated with a swellable hydrogel to increase coverage density. Other optionis (such as urethane coating) are possible as well. [0070] The cover can be delivered through the lumen of a micro catheter (using a pusher or guide) or it can be configured to be placed on the end of a delivery catheter and released off the tip of the catheter by means of a pull wire or pull back sheath. The implant can also be rolled or furled on a catheter tip into its double-braid shape and deployed via wire release or pull back sheath. The design of a single-layer braid allows the implant to be deliverable in a sheath sized to navigate in cerebral vasculature. Once at the target site, the single-layer tube assumes its double-layer configuration to provide maximum flow diversion at the target aneurysm. Embodiments of the device having an alignment wire can be similarly delivered.

[0071] The cover can also be delivered out of a side hole at the distal end of a catheter, using a guidewire for proper alignment of the device. If required to ensure apposition, a balloon can be placed on the delivery catheter. Additionally, to anchor the catheter during delivery, a distal balloon can be inflated while the cover is deployed through a side hole in the catheter.

[0072] Polymer fibers may be incorporated in the implant as part of an alternative delivery system. When forming a cover from Nitinol that contains one or more polymer fibers, the tube is heat set first, then one or more polymer fibers are interlaced in the braid for connecting to a delivery guide or pusher. The cover is released from the guide by melting the polymer fibers. Remnants of polymer remain in the device. Polyethylene suture can also be used, or another material. The suture materials offer a strong and pliable means of retention until severed. Although having less strength than non-absorbable suture, bioabsorbable suture (e.g. PLA₁ PGLA) may be also be used. The fibers can run lengthwise or crosswise to connect the cover to the delivery wire or guide. The polymer laced cover can be single or double-layered braid. For delivery of a double-layer cover, the polymer fibers can tie the double-layer cover to a delivery mandrel, and release the cover at the target site.

[0073] Detachment of a cover having polymer fibers for holding the cover on a wire, mandrel, or connected to some sort of delivery guide can be accomplished by application of heat, e.g., electrical current, such as described in USPN 6,607,539 to Hayashi et al., which is hereby incorporated by reference in its entirety. [0074] Once delivered, the cover conforms to the vessel wall and stays in location due to the elastic nature of the braid material, the secondary shape to which the braid is trained by heat setting (which is stronger than the single-layer tube), and the size of the secondary shape relative to the vessel size (optimally the cover is oversized for the target artery). The radial force of the double-layered implant opposes the walls of the artery and provides a snug fit for the implant at the aneurysm. Size variables can be adjusted to specify a preform single-layer tube with desired braid density, flexibility and radial force that will form a double- layer braid implant capable of providing the appropriate flow diversion at the aneurysm.

[0075] Other embodiments include covers having single-layer braid or mesh placed on supportive scaffolds having an alignment wire loop attached to the cover that extend into an aneurysm for positioning the cover at the aneurysm opening. The wire will be oriented generally perpendicular to the axis of the cover when the device is placed at the aneurysm. The cover having a wire alignment member can also have polymer fibers interlaced within the braid or mesh for delivery purposes. The wire number, PIC, and wire size of the braid or mesh of these covers can be adjusted to provide maximal occlusion of an aneurysm using a single-layer cover and/or achieve better deliverability. [0076] Fig. 28A depicts a disc-shaped double-layer braid structure 224 placed at an aneurysm 222 in blood vessel 220 in longitudinal cross-section. Fig. 28B depicts the same disc-shaped braid structure 224 at aneurysm 222, in vessel 220, but in cross-section, showing the placement and relative coverage of the vessel with the disc-shaped cover. Fig. 28B depicts that the cover 224 is greater than 50% contiguous with the blood vessel.

[0077] Fig. 29A depicts a catheter 226 delivering a braid disc 224 to aneurysm 222 in vessel 220 over guidewire 228. Guidewire 228 extends through the catheter and into the aneurysm for guiding positioning of the disc-shaped cover at the aneurysm.

[0078] Fig. 29B depicts a delivery tube 232 retaining disc-shaped braid cover 230. Guidewire 228 extends through side port 246 to guide the delivery and placement of the cover.

[0079] Fig. 3OA depicts delivery of disc-shaped braid cover 230 from sideport 246 of pull back delivery sheath 232 in vessel 220. At the distal end of the delivery sheath is balloon 234 for securing the delivery system while the cover is being deployed. Fig. 3OB depicts a delivery system configured to deliver disc-shaped cover 224 positioned at the distal end of the delivery sheath 232, with guidewire 228 guiding placement of the cover at the aneurysm. Delivery tube 236 does not have a sideport in this embodiment, and the cover is pushed out of from the distal end of the delivery sheath.

[0080] Fig. 31 A and 31 A' depict a tube of braid 238 that is flattened to become an elongate rectangle in Fig. 31 B and 31 B'. Fig. 31 C shows the transformation of the elongate rectangle into the three-dimensional two-layered cover 242. The cover 242 is shown over mandrel 244. Fig. 31 D depicts cover 242. Fig. 31 E depicts an elongate rectangle formed into a secondary shape of an open tube 236. The open double-braid tube when placed in a blood vessel will be contiguous with most of the blood vessel.

[0081] Fig. 32A depicts delivery of a braid cover 242 using delivery catheter 248. The cover is pushed from the sheath to release and form its three- dimensional secondary shape at the aneurysm. Fig. 32B depicts a cross-sectional view of cover 242 when fully positioned in the blood vessel. Cover 242 is depicted as being greater than 50% contiguous with the vessel in this embodiment. [0082] Fig. 33A depicts a heat-set double-layer braid cover 250 having polymer fibers 252 interwoven in the wire braid. Fig. 33B shows the braid cover loaded on a mandrel 254 for delivery. Polymer fibers 252 are connected at distal and proximal ends to the mandrel at conductive bands 256. The bands, which can be nichrome wire, are flanked by conductive ribbon 258, e.g. copper ribbon. Upon application of a small voltage (e.g. 2 to 4 V) the nichrome will heat to a temperature sufficient to melt the polymer fibers 252 and release the cover from the mandrel. Some polymer fiber will remain with the cover. Connection over the mandrel allows the delivery system to manipulate and control the placement of the cover at the target site.

[0083] The polymer delivery system can also be used with single-layer braid covers, especially those having alignment wire loops. The polymer fibers elongate the cover over a guidewire and bind the wire loop to the guidewire in at least one spot. Once at the target site, the polymer fibers are melted/severed by heat to release the cover and allow the wire loop to extend perpendicularly up from the cover into the aneurysm.

[0084] Fig. 34A illustrates cover device 18 positioned within the blood vessel so that the device covers the opening of aneurysm A. Wire 26 protrudes into the aneurysm from cover 18 to assist in holding the cover in place. Thus, blood flows through the vessel and is blocked by cover 18 from entering aneurysm A. Alignment element 26 can be a radiopaque filament (e.g., Pt/NiTi DFT) to assist in determining when the covering 18 is desirably aligned over the aneurysm A. Such alignment may be detected by monitoring the radiopaque filament 26 under medical imaging until it is within the aneurysm A. Other examples of alignment elements include a balloon, which may be inflated into the aneurysm A when desirably aligned, or a fluid port which passes fluid into aneurysm A when desirably aligned. The cover can be single-layered braid or mesh or double- layered braid.

[0085] Fig. 34B depicts a cross sectional view of a cover device 18 positioned over a mandrel 22, having alignment element comprising radiopaque filament 26 for positioning the cover at the aneurysm. As illustrated in Fig. 34C and Fig. 34D, the radiopaque filament 26 can be length-wise (Fig. 34C) or cross-wise (Fig. 34D) over the cover to align the cover at the aneurysm. [0086] It is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there is a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms "a," "an," "said," and "the" include plural referents unless specifically stated otherwise. In other words, use of the articles allow for "at least one" of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only" and the like in connection with the recitation of claim elements, or use of a "negative" limitation.

[0087] Without the use of such exclusive terminology, the term "comprising" in the claims shall allow for the inclusion of any additional element irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.

[0088] The breadth of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of the claim language. Any method herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events, or slight modifications of those events or the event order.

[0089] All references cited are incorporated by reference in their entirety. Although the foregoing invention has been described in detail for purposes of clarity of understanding, it is contemplated that various alternatives, modifications and equivalents may be used. Accordingly, the above description should not be taken as limiting the scope of the invention defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. An aneurysm cover system for isolating an aneurysm comprising: a double-layer wire braid cover to occlude an aneurysm, the cover adapted to assume a single-layer tube shape for delivery, and to form the double-layer cover upon release.

2. An aneurysm cover system for isolating an aneurysm comprising: an occluding wire braid or mesh cover supported on an open ring scaffold at an aneurysm, the cover comprising a wire loop extension positioned substantially perpendicular to the cover for aligning the cover at the aneurysm, the wire loop configured to extend into the aneurysm.

3. A aneurysm cover system for isolating an aneurysm comprising: an aneurysm cover of flat wire braid or mesh, the cover further comprising one or more polymer fibers interlaced in the braid or mesh attaching the cover to a delivery guide, the one or more polymer fibers severable from the guide upon application of heat to the fiber.

4. The cover system of claim 3, wherein the flat braid or mesh is double-layered.

5. The cover system of claim 4, wherein the flat double-layered braid or mesh is adapted to form a concave or curved double-layered cover upon release from the delivery guide.

6. The cover system of claim 1 or 2, wherein the system further comprises: one or more polymer fibers interlaced in the braid attaching the cover to a delivery guide, the one or more polymer fibers severable from the guide upon application of heat to the fiber.

7. The cover system of claim 1 or 3, the system further comprising; a wire loop extension positioned substantially perpendicular to the cover for aligning the cover at the aneurysm, the wire loop configured to extend into the aneurysm.

8. The cover system of claim 2 or 3, the system comprising: wherein the cover comprises a double-layer braid cover, the cover adapted to assume a single-layer tube shape for delivery, and to form the double-layer cover upon release.

9. The cover system of claim 1 , wherein the double-layer cover is a concave disc.

10. The cover system of claim 8, wherein the double-layer cover is a concave disc.

11. The cover system of claim 1, wherein the double-layer cover is a curved rectangle.

12. The cover system of claim 8, wherein the double-layer cover is a curved rectangle.

13. The cover system of claim 1, 2, or 3 wherein the wire comprises NiTi alloy that is superelastic at body temperature.

14. A method of delivering a cover device to isolate an aneurysm comprising: interlacing one or more polymer fibers within the braid of a double- layer wire braid cover formed from a compressed and heat set single-layer braid tube, connecting the one or more interlaced polymer fibers to a delivery guide to hold the cover in place over the guide, delivering the cover to a target aneurysm in cerebral vasculature, melting the polymer fibers to release the cover from the guide.