Controlled deployable medical device and method of making the same

Controlled deployable medical devices that are retained inside a body passage and in one particular application to vascular devices used in repairing arterial dilations, e.g., aneurysms. Such devices can be adjusted during deployment, thereby allowing at least one of a longitudinal or radial re-positioning, resulting in precise alignment of the device to an implant target site.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates generally to devices that are retained inside a body passage and in one particular application to vascular devices used in repairing arterial dilations, e.g., aneurysms. More particularly, the invention is directed toward devices that can be adjusted during deployment, thereby allowing at least one of a longitudinal or radial re-positioning of the device.

Discussion of the Related Art

The invention will be discussed generally with respect to deployment of a bifurcated stent graft into the abdominal aorta but is not so limited and may apply to device deployment into other body lumens. When delivering a stent graft by intraluminal or endovascular methods, it is important to know the precise location of the device in the vasculature. Controlling this precise location is particularly important when the device is intended to be deployed in close proximity to branch vessels or adjacent to weakened portions of the aortic wall. Typical stent grafts used to repair an aortic aneurysm incorporate a proximal (i.e. portion of the stent graft closest to the heart) anchoring system intended to limit longitudinal displacement of the stent graft. Often this anchoring system must be precisely placed to avoid occlusion of a branch vessel or to avoid placement within a compromised and damaged portion of the aortic wall.

An improved delivery system for such stent grafts would include a means for allowing precise longitudinal and rotational placement of the stent graft and anchoring system. The precise position of the stent graft and anchoring system would be adjusted and visualized prior to full deployment of the device. Ideally the delivery system would allow the device to be repositioned if the prior deployment position was undesirable.

SUMMARY OF THE INVENTION

The present invention is directed to a controlled deployable medical device and method of making the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An embodiment of the present invention provides an apparatus, comprising a catheter having a proximal end portion and distal end portion. A hub can be arranged on a distal end portion of the catheter. A stent member is arranged on the proximal end portion of the catheter, the stent member has an inner surface and an outer surface. The stent can be configured in any suitable manner. In an embodiment of the invention, the stent is configured from multiple turns of an undulating element. Such a stent member can have substantially in-phase undulations. A graft member can be arranged about the stent member. Moreover, an element can be connected to a torsional member, wherein the torsional member is capable of retracting a portion of the element and thereby radially compressing at least a portion of the stent.

In another embodiment, the present invention provides an apparatus substantially as described above, further comprising a tube having a proximal end portion and distal end portion arranged on at least a portion of the substantially tubular shaped stent member, wherein at least a portion of the torsional member extends within a portion of the tube.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention relates generally to a novel medical apparatus that includes a device capable of being retained inside a body passage and in one particular application to vascular devices. More particularly, the invention is directed toward devices that can be adjusted during deployment, thereby allowing at least one of a longitudinal or radial re-positioning. The term distal as used herein denotes a position furthest from the heart, while the term proximal denotes a position closest to the heart.

In an embodiment of the invention, the medical apparatus includes a catheter assembly having a proximal end portion and distal end portion. A hub can be optionally arranged on a distal end portion of the catheter assembly. A stent is arranged on a proximal end portion of the catheter. A graft member can be arranged about at least a portion of the stent. The stent may be self-expandable, balloon-expandable or a combination of self-expandable and balloon-expandable.

In some embodiments, the stents can be used to fix the medical apparatus inside a portion of a patient's anatomy. The stent can be preferably constructed from materials that are flexible and strong. The stent can be formed from degradable bioabsorable materials, biodigestible materials, polymeric materials, metallic materials and combinations thereof. In addition, these materials may be reinforced and/or coated with other materials, such as polymeric materials and the like. The coating may be chosen to reduce acidic or basic effects of the gastrointestinal tract, e.g., with a thermoplastic coating such as ePTFE and the like.

More specifically, the stents can be fabricated according to the methods and materials as generally disclosed in, for example, U.S. Pat. No. 6,042,605 issued to Martin, et al., U.S. Pat. No. 6,361,637 issued to Martin, et al. and U.S. Pat. No. 6,520,986 issued to Martin, et al. For example, stents can have various configurations as known in the art and can be fabricated, for example, from cut tubes, wound wires (or ribbons), flat patterned sheets rolled into a tubular form, combinations thereof, and the like. Stents can be formed from metallic, polymeric or natural materials and can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol and biologically derived materials such as bovine arteries/veins, pericardium and collagen. Stents can also comprise bioresorbable materials such as poly(amino acids), poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) and poly(orthoesters).

The stents can be formed into a variety of different geometric configurations having constant and/or varied thickness as known in the art. The geometric configurations may include many conventional stent configurations such as a helically wrapped stent, z-shape stent, tapered stent, coil stent, combinations thereof, and the like. The stents can be formed in a variety of patterns, such as, a helix pattern, ring pattern, combinations thereof, and the like.

Grafts can have various configurations as known in the art and can be fabricated, for example, from tubes, sheets or films formed into tubular shapes, woven or knitted fibers or ribbons or combinations thereof. Graft materials can include, for example, conventional medical grade materials such as nylon, polyester, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylchloride, polyurethane and elastomeric organosilicone polymers.

Stents can be used alone or in combination with graft materials. Stents can be configured on the external or internal surface of a graft or may be incorporated into the internal wall structure of a graft. Stent or stent grafts can be delivered endoluminally by various catheter based procedures known in the art. For example self-expanding endoluminal devices can be compressed and maintained in a constrained state by an external sheath. The sheath can be folded to form a tube positioned external to the compressed device. The sheath edges can be sewn together with a deployment cord that forms a “chain stitch”. To release and deploy the constrained device, one end of the deployment cord can be pulled to disrupt the chain stitch, allowing the sheath edges to separate and release the constrained device. Constraining sheaths and deployment cord stitching can be configured to release a self-expanding device in several ways. For example a constraining sheath may release a device starting from the proximal device end, terminating at the distal device end. In other configurations the device may be released starting from the distal end. Self expanding devices may also be released from the device center as the sheath disrupts toward the device distal and proximal ends.

Details relating to constraining sheath materials, sheath methods of manufacture and stent graft compression techniques can be found in, for example, U.S. Pat. No. 6,352,561 issued to Leopold, et al., and U.S. Pat. No. 6,551,350 issued to Thornton, et al.

The catheter and hub assemblies can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyether block amide or thermoplastic copolyether, polyvinylchloride, polyurethane, elastomeric organosilicone polymers, and metals such as stainless steels and nitinol.

Turning to the figures,FIG. 1Ais a medical apparatus according to an embodiment of the invention.FIG. 1Bis an enlarged simplified view of a portion of the medical apparatus shown inFIG. 1A.

Referring toFIGS. 1A and 1B, the medical apparatus is generally depicted as reference numeral100A. The medical apparatus100A includes catheter assembly102, stent104arranged on the proximal end portion of the catheter assembly102. The stent104has an inner surface, an outer surface, and is configured from multiple turns of an undulating element105. The undulating element105can be configured, for example, in a ring or helical pattern.

The stent104has a proximal end portion106and distal end portion108. The distal end portion108is formed into a branch having a first leg110and a second leg112.

A graft member114is arranged about the stent104.

In an embodiment of the invention, the stent104and graft member114are constrained into a compacted delivery state by a first sheath116and second sheath118. As shown inFIG. 1A, the first sheath116has been released allowing at least a portion of the stent104to expand as shown. The second sheath118is coupling the second leg112to the catheter assembly102as shown.

A torsional member120extends from a proximal end portion to a distal end portion of the catheter assembly102. In the figure, the torsional member120is positioned adjacent the outer surface of the stent104and graft114. The torsional member120is attached to the catheter assembly102and not attached to the stent104or graft114. A movable element122having a first end124and second end126surrounds the stent104and graft member114. The first end124and second end126of the movable element122extend out a distal end portion of the torsional member120. For example, the movable element122is threaded through the tube from a distal end to a proximal end and is looped around the proximal end portion106of the stent104and graft member114.

As shown inFIG. 1B, the torsional member120can be rotated in the direction shown by arrow130, tensioning the movable element122thereby causing at least a portion of the stent/graft to radial compress in the direction indicated by arrows128. The torsional member120can be configured with a side-wall aperture132through which the two ends124,126of the movable element122can be routed. The torsional member120can be rotated by turning the distal end of the tube120. The torsional member120can be rotated in the opposite direction (of that shown by arrow130) to allow the stent/graft to expand in the direction opposite of arrows128. The stent/graft can be compressed to allow rotational or longitudinal displacements within a vessel. When the desired placement is verified, the stent/graft can be allowed to expand and engage the vessel wall. Repeated compressions and expansions of the stent/graft can be utilized as desired. The stent/graft can also be gradually compressed or allowed to gradually expand by varying the amount of twist imparted to the torsional member120. After final placement of the stent/graft, tension can be applied to one of the ends124,126of the moveable element122to release and withdraw the movable element.

FIG. 1Cis a medical apparatus according to a further embodiment of the invention, having a torsional member120positioned internal to the stent/graft.

Referring toFIG. 1C, the medical apparatus is generally depicted as reference numeral100B. The medical apparatus ofFIG. 1Cis similar to the medical apparatus as shown inFIGS. 1A and 1B. The medical apparatus includes a stent104and/or a graft114arranged on the proximal end portion of the catheter assembly.

A torsional member120extends from a proximal end portion to a distal end portion of the catheter assembly. The torsional member120is positioned internal to the stent104and graft114. The torsional member120is attached to the catheter assembly and not attached to the stent104or graft114. A movable element122having a first end124and second end126is looped through and around the stent104and graft member114. The first end124and second end126of the movable element122extend out a distal end portion of the torsional member120. For example, the movable element122is threaded through the tube from a distal end to a proximal end and is looped around the proximal end portion of the stent104and graft member114. As shown inFIG. 1C, the torsional member120can be rotated in the direction shown by arrow130, tensioning the movable element122thereby causing at least a portion of the stent/graft to radial compress in the direction indicated by arrows128. The torsional member120can be configured with a side-wall aperture132through which the two ends124,126of the movable element122can be routed. The torsional member120can be rotated by turning the distal end of the torsional member120. The torsional member120can be rotated in the opposite direction (of that shown by arrow130) to allow the stent/graft to expand in the direction opposite of arrows128. The stent/graft can be compressed to allow rotational or longitudinal displacements within a vessel. When the desired placement is verified, the stent/graft can be allowed to expand and engage the vessel wall. Repeated compressions and expansions of the stent/graft can be utilized as desired. The stent/graft can also be gradually compressed or allowed to gradually expand by varying the amount of twist imparted to the torsional member120. After final placement of the stent/graft, tension can be applied to one of the moveable ends124,126of the moveable element122to release and withdraw the movable element.

FIGS. 2A and 2Bare partial views of the proximal end of a medical apparatus according to a further embodiment of the invention, having releasable straps that can radial compress a stent/graft.

Referring toFIGS. 2A and 2B, the medical apparatus is generally depicted as reference numeral200. The medical apparatus ofFIGS. 2A and 2Bis similar to the medical apparatus as shown inFIGS. 1A through 1Cwith a stent/graft not shown for clarity.

Shown inFIG. 2Ais a partial cross-section of a distal end of a catheter system200having an outer tube202. Contained within the outer tube202are a first inner tube204and a torsional member206. Attached to the torsional member is at least one flexible strap208. The flexible strap208surrounds a distal portion of a stent/graft (not shown). When the torsional member206is rotated as depicted by arrow210the strap208is further wound around the torsional member206, thereby “drawing in” the strap which will in turn, compress a surrounded stent/graft. The degree of stent/graft compression can be controlled by varying the amount of twist imparted to the torsional member. A first end212of a flexible strap208can be affixed to the torsional member206. The second end214of the strap208can be wrapped around the torsional member. When the medical apparatus is properly positioned with a target site, the torsional member can be rotated in a direction opposite that shown by arrow210. This opposite rotation will allow the stent/graft to fully expand. Further opposite rotation of the torsional member will cause the strap end214to “un-wind” from the torsional member. The torsional member can then be withdrawn in a distal direction, pulling the strap with attached end212into the first inner tube. In an alternate method the first inner tube and the torsional member can be withdrawn together or all three members (204,206,208) can be withdrawn together.

Shown inFIG. 2Bis a non cross-sectional perspective view of the distal end of the catheter system shown inFIG. 2A. The flexible straps208can be fabricated from various bio-compatible materials as commonly known in the art.

FIGS. 3A and 3Bare partial perspective views of a medical apparatus according to a further embodiment of the invention.

Referring toFIGS. 3A and 3B, the medical apparatus is generally depicted as reference numeral300A or300B. The medical apparatus300A and B includes catheter assembly102, stent104arranged on the proximal end portion of the catheter assembly102. The stent104has an inner surface, an outer surface, and is configured from multiple turns of an undulating element105. The undulating element105can be configured, for example, in a ring or helical pattern.

The stent104has a proximal end portion106and distal end portion108. The distal end portion108is formed into a branch having a first leg110and a second leg112.

A graft member114is arranged about the stent104.

The stent104and graft member114are constrained into a compacted delivery state by a first sheath116and second sheath118.

As shown inFIGS. 3A and 3B, the first sheath116has been released allowing at least a portion of the stent104to expand as shown. The second sheath118is coupling the second leg112to the catheter assembly102as shown.

Shown inFIG. 3Ais a flexible constraining sleeve302, surrounding a proximal portion of the stent/graft. A torsional member120extends from a proximal end portion to a distal end portion of the catheter assembly102. In the figure, the torsional member120is positioned adjacent the outer surface of the stent104and graft114. The torsional member120is attached to the catheter assembly102and not attached to the stent104or graft114. The flexible sleeve302is attached to the torsional member120so that when the torsional member120is rotated, the flexible sleeve is compressed which in turn compresses the stent/graft. The flexible sleeve302is shown having a parting or rip cord304. The rip cord304can be in the form of a thread or wire that is contained within a secondary tube306. The secondary tube306can exit the distal end of the catheter assembly102with the rip cord exiting the distal end of the secondary tube. When the medical apparatus is properly deployed the distal end of the rip cord can be tensioned, thereby ripping or separating the flexible sleeve302. Since the flexible sleeve is still attached to the torsional member120, the flexible sleeve302can then be withdrawn along with the catheter assembly102.

Shown inFIG. 3Bis a flexible constraining sleeve302, surrounding a proximal portion of the stent/graft. A torsional member310extends from a proximal end portion to a distal end portion of the catheter assembly102. In the figure, the torsional member310is positioned adjacent the outer surface of the stent104and graft114. The torsional member310is attached to the catheter assembly102and not attached to the stent104or graft114. The flexible sleeve302is attached to the torsional member310so that when the torsional member310is rotated, the flexible sleeve is compressed which in turn compresses the stent/graft. The flexible sleeve302is shown having a parting line312. Shown is a stitched parting line312similar to those parting lines incorporated into the first116and second118sheaths. The release of the stitched parting line312can be activated by a release cord314. The release cord314can be in the form of a thread or wire and can be contained within a secondary tube (not shown) or be contained within a catheter system lumen. The release cord314can exit the distal end of the catheter assembly102. When the medical apparatus is properly deployed the distal end of the release cord314can be tensioned, thereby un-stitching or separating the flexible sleeve302. Since the flexible sleeve is still attached to the torsional member310, the flexible sleeve302can then be withdrawn along with the catheter assembly102.