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  Implantable stent delivery devices and methodsUSPTO Application #: 20080097574Title: Implantable stent delivery devices and methods Abstract: Stent delivery devices include at least one implantable stent carrier and/or membrane for carrying multiple stents or stent segments over an expandable member. At least a portion of the implantable carrier is expandable by the expandable member to deploy the portion of the carrier and one or more stent segments disposed thereon. A sheath may be retracted to expose and expand a distal portion of the expandable member to expand and deploy a distal portion of the carrier and the stent segment(s) disposed thereon. Stent delivery devices and methods provide enhanced delivery of multiple stents or stent segments by delivering the segments while coupled with one or more implantable carriers and/or membranes that are typically flexible and dividable. (end of abstract) Agent: Townsend And Townsend And Crew, LLP (client No 021629-000000) - San Francisco, CA, US Inventors: Bernard Andreas, Jeffry J. Grainger USPTO Applicaton #: 20080097574 - Class: 623001120 (USPTO) Related Patent Categories: Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor, Arterial Prosthesis (i.e., Blood Vessel), Stent Combined With Surgical Delivery System (e.g., Surgical Tools, Delivery Sheath, Etc.), Expandable Stent With Constraining Means The Patent Description & Claims data below is from USPTO Patent Application 20080097574. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCES TO RELATED APPLICATIONS [0001] The present application is a continuation of U.S. application Ser. No. 10/687,532 (Attorney Docket No. 021629-002100US), filed Oct. 15, 2003, the full disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to medical devices and methods. More particularly, the invention relates to apparatus and methods for independently delivering segmented stents or stent grafts within a body lumen. [0004] Stenting has become an increasingly important treatment option for patients with coronary artery disease. Stenting involves the placement of a tubular prosthesis within a diseased coronary artery to expand the arterial lumen and maintain the patency of the artery. Early stent technology suffered from problems with restenosis, the tendency of the coronary artery to become re-occluded following stent placement. In recent years, however, improvements in stent design and the advent of drug-eluting stents have reduced restenosis rates dramatically. As a result, the number of stenting procedures being performed in the United States, Europe, and elsewhere has soared. [0005] Stents are delivered to the coronary arteries using long, flexible vascular catheters, typically inserted through a femoral artery. For self-expanding stents, the stent is simply released from the delivery catheter, and it resiliently expands into engagement with the vessel wall. For balloon expandable stents, a balloon on the delivery catheter is expanded which expands and deforms the stent to the desired diameter, whereupon the balloon is deflated and removed. [0006] Despite many recent advances in stent delivery technology, a number of shortcomings still exist. For example, current stent delivery catheters are not capable of customizing the length of the stent in situ to match the size of the lesion to be treated. While lesion size may be measured prior to stenting, using angiography or fluoroscopy, such measurements may be inexact. If a stent is introduced that is found to be of inappropriate size, the delivery catheter and stent must be removed from the patient and replaced with a different device of correct size. Moreover, current stent delivery devices cannot treat multiple lesions with a single catheter. If multiple lesions are to be treated, a new catheter and stent must be introduced for each lesion to be treated. [0007] Additionally, currently available stent delivery devices are not well-adapted for treating vascular lesions that are very long and/or in curved regions of a vessel. Current stents have a discrete length that is relatively short due to their stiffness. If such stents were made longer, to treat longer lesions, they would not conform well to the curvature of vessels or to the movement of vessels on the surface of the beating heart. On the other hand, any attempt to place multiple stents end-to-end in longer lesions is hampered by the inability to maintain appropriate inter-stent spacing and to prevent overlap of adjacent stents. Such shortcomings in the prior art are addressed by the inventions described in U.S. patent application Ser. No. 10/412,714 (Attorney Docket No. 21629-000330), entitled "Apparatus and Methods for Delivery of Multiple Distributed Stents," filed on Apr. 10, 2003; and U.S. patent application Ser. No. 10/637,713 (Attorney Docket No. 21629-000340), entitled "Apparatus and Methods for Delivery of Multiple Distributed Stents," filed on Aug. 8, 2003; both applications assigned to the assignee of the present invention, and both applications being hereby incorporated fully by reference. [0008] Even with improvements such as those described in the above-referenced patent applications, further improvements in stent delivery devices and methods are still being sought. For example, flexibility of a stent is important in stenting long lesions, tortuous vessels, lesions at vessel branches and the like. The above referenced patent applications disclose the use of segmented stents with separate or separable segments to provide highly flexible stents of selectable length. However, in some cases it may be advantageous to use segments that are coupled together during deployment to maintain segment alignment and prevent mobilization of the segments. It may also be beneficial to use interconnected stents to form a tubular passage, such as a graft. [0009] As another example, many balloon-expandable stents are currently delivered by devices in which the stents are in direct contact with the balloon or other expandable member. If such stents are pushed or otherwise advanced along the expandable member in its deflated state, the direct contact between the stents and the balloon during advancement may cause damage to the balloon and/or to the stents or their coatings. A balloon or other expandable member may also interfere with stent advancement, especially after the balloon has been inflated and deflated multiple times and, thus, becomes somewhat flaccid and/or deformed. Thus, stent delivery devices in which the stents directly contact the expandable member may lead to increased risk of balloon or stent damage, increased general wear and tear, difficult stent advancement along the delivery device, and less precise stent placement. [0010] Therefore, a need exists for improved stent delivery devices and methods. Ideally, such devices and methods would provide flexible coupling of stent segments during deployment of the segments. Also ideally, such devices and methods would at least reduce direct contact between stents and the expandable member of the delivery device to reduce damage to the stents and expandable member and to facilitate stent placement. At least some of these objectives will be met by the present invention. [0011] 2. Description of the Background Art [0012] U.S. patent application Ser. Nos. 10/412,714 and 10/637,713, previously incorporated by reference, describe apparatus and methods for delivery of multiple distributed stents. U.S. Pat. Nos. 6,485,510 and 6,258,117 to Camrud et al. describe segmented stents with breakable connections between the segments. U.S. Patent Application Publication No. 2002/0156496 (inventor Chermoni) describes a catheter for carrying stents including a stent positioner. U.S. Pat. No. 6,143,016 to Beam et al. describes a stent delivery sheath. U.S. Pat. No. 5,807,398 to Shaknovich describes a shuttle stent delivery catheter. U.S. Pat. Nos. 5,571,086 (Kaplan et al.) and 5,776,141 (Klein et al.) describe an expandable sleeve for placement over a balloon catheter for the delivery of one or two stent structures to the vasculature. U.S. Pat. No. 5,697,948 to Marin et al. describes a catheter for delivering stents covered by a sheath. Patent application serial numbers 2003/0139797 (Johnson) and 2003/0114919 (McQuiston) describe covered segmented stents. BRIEF SUMMARY OF THE INVENTION [0013] Stent delivery devices and methods of the present invention provide for delivering a plurality of stents, a segmented stent or stent grafts in body lumens. Generally, devices of the invention include a stent delivery catheter having at least one implantable carrier and/or membrane for carrying segmented stents. The carrier or membrane allows multiple segments of a stent to be coupled together flexibly during deployment. In some embodiments, the carrier or membrane helps prevent damage to stent segments or to an expandable member caused by contact between the segments and the member. In some embodiments, stent segments and the carrier(s) and/or membrane(s) are deployed from the catheter by retracting a sheath to expose and expand an expandable balloon. The exposed, expanded balloon expands a portion of the implantable carrier or membrane and one or more stent segments disposed thereon, thus deploying the carrier and the segments. In some embodiments, the sheath may subsequently be drawn proximally to further expose and expand the balloon, thus deploying additional portion(s) of the carrier and one or more additional stent segments disposed thereon. [0014] Various embodiments of the invention may be configured to individually and/or selectively deliver multiple stents, multiple stent segments of one stent, multiple stent grafts or stent graft segments, or the like. Although the following description often refers to delivery of "stent segments," this phrase should not be interpreted to limit the scope of the invention in any way. Generally, devices and methods of the invention may be used to delivery any suitable luminal prosthesis, multiple prostheses, or multiple prosthesis segments to a body lumen, and are thus not limited to delivery of one stent, segmented stents or the like. [0015] In one aspect of the present invention, a stent delivery device for delivering a plurality of stents or stent segments to a treatment site comprises: a catheter shaft having a proximal end and a distal end; an expandable member coupled with the catheter shaft near the distal end; at least one implantable carrier disposed over the expandable member; a plurality of stent segments disposed along the carrier; and a sheath slidably disposed over the implantable carrier to constrain expansion of a proximal portion of the expandable member while allowing expansion of a distal portion of the expandable member. The expanded distal portion of the expandable member expands a distal portion of the implantable carrier and at least one stent segment disposed thereon to deliver the distal portion of the implantable carrier and the at least one stent segment. [0016] In some embodiments, the implantable carrier is slidably disposed over the expandable member, while in other embodiments, the carrier may have a fixed position. In slidable embodiments, the catheter device may further include a carrier shaft coupled with the implantable carrier and disposed over the catheter shaft proximal to the implantable carrier for advancing the carrier distally. [0017] Optionally, the sheath may further include at least one carrier cutting member disposed to cut the implantable carrier at one or more locations between the stent segments. For example, the carrier cutting member may comprise a sharpened edge disposed circumferentially about an inner surface of the sheath at a distal end of the sheath. Such embodiments may also include a protective member disposed between the sharpened edge and the expandable member to prevent damage to the expandable member by the sharpened edge. In some embodiments, the carrier cutting member may act as a valve member to provide control of a number of stents segments delivered by the device. Also in some embodiments, expanding the expanding member may press the implantable carrier against the carrier cutting member to divide the distal portion of the carrier from a proximal portion of the carrier. [0018] In some embodiments, the implantable carrier includes at least one dividable connection between at least the distal portion of the carrier and a proximal portion of the carrier. In fact, some embodiments may include multiple dividable connections between multiple carrier portions. Such dividable connections may comprise, for example, perforations, frangible connections, an area of material along the carrier that is thinner than immediately adjacent areas of material, and/or the like. Such connections may be configured to separate or break upon expansion of the expandable member, with or without the use of a cutting member on the sheath. Some of such connection may remain intact following deployment and may remain permanently connected, or may degrade and separate over time. [0019] The carrier itself may be made of any suitable material or combination of materials, such as but not limited to polymers, metals, metal alloys, woven polyesters, polytetrafluoroethylene, ceramics, human tissues, animal tissues and/or the like. In some embodiments, the implantable carrier may include at least one biodegradable or bioresorbable material, or may be made wholly of biodegradable or bioresorbable materials. Also in some embodiments, the implantable carrier may include at least one pharmacological or biological agent, such as but not limited to Rapamycin, Paclitaxel, Rapamycin or Paclitaxel analogs, prodrugs, or derivatives, Everolimus and derivatives thereof, antibiotics, thrombolytics, anti-thrombotics, anti-inflammatories, cytotoxic agents, anti-proliferative agents, vasodilators, gene therapy agents, radioactive agents, immunosuppressants, chemotherapeutics, stem cells and/or the like. In some embodiments, the implantable carrier is non-porous so as to act as a vascular graft, while in other embodiments the carrier is partially or completely porous. In various embodiments, the implantable carrier may comprise a solid tubular wall, a tubular mesh, a tubular scaffold, a helical coil, multiple axial beams or the like. The stent segments may be either fixedly or slidably disposed along the carrier, according to various embodiments. [0020] In some embodiments, the stent delivery device may further include at least one membrane coupled with at least one of the stent segments. In some embodiments, the membrane comprises a continuous membrane coupled with a plurality of stent segments. Alternatively, a plurality of membranes may be coupled with the stent segments such that each membrane is coupled with one of the stent segments or each membrane is coupled with two or more segments. The membrane may be either impermeable or impermeable and may be made of any suitable material or materials. For example, the membrane may comprise at least one biodegradable or bioresorbable material. The membrane may also include at least one pharmacological or biological agent, such as but not limited to Rapamycin, Paclitaxel, Rapamycin or Paclitaxel analogs, prodrugs, or derivatives, antibiotics, thrombolytics, anti-thrombotics, anti-inflammatories, cytotoxic agents, anti-proliferative agents, vasodilators, gene therapy agents, radioactive agents, immunosuppressants, chemotherapeutics, stem cells and/or the like. [0021] In another aspect of the present invention, a stent delivery device for delivering a plurality of stents or stent segments to a treatment site comprises: a catheter shaft having a proximal end and a distal end; an expandable member coupled with the catheter shaft near the distal end; at least one implantable membrane disposed over the expandable member; a plurality of stent segments disposed along the membrane; and a sheath slidably disposed over the implantable membrane to constrain expansion of a proximal portion of the expandable member while allowing expansion of a distal portion of the expandable member. The expanded distal portion of the expandable member expands a distal portion of the implantable membrane and at least one stent segment disposed thereon to deliver the distal portion of the implantable membrane and the at least one stent segment. The membrane or membranes may have any of the characteristics of the membranes described above. Continue reading... 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