US20050288766A1 - Devices and methods for controlling expandable prostheses during deployment - Google Patents

Abstract

Prosthesis delivery devices and methods are provided that enable precise control of prosthesis position during deployment. The prosthesis delivery devices may carry multiple prostheses and include deployment mechanisms for delivery of a selectable number of prostheses. Control mechanisms are provided in the prosthesis delivery devices that control either or both of the axial and rotational positions of the prostheses during deployment. This enables the deployment of multiple prostheses at a target site with precision and predictability, eliminating excessive spacing or overlap between prostheses. In particular embodiments, the prostheses of the invention are deployed in stenotic lesions in coronary or peripheral arteries or in other vascular locations.

Description

BACKGROUND OF THE INVENTION
• Stents are tubular prostheses designed for implantation in a vessel to maintain patency of the vessel lumen. Stents are used in various vessels throughout the body, including the coronary arteries, femoral arteries, iliac arteries, renal artery, carotid artery, vascular grafts, biliary ducts, trachea, and urethra, to name some examples. Stents are typically implanted by means of long and flexible delivery catheters that carry the stents in a compact, collapsed shape to the treatment site and then deploy the stents into the vessel. In some applications, balloon expandable stents are used. These stents are made of a malleable metal such as stainless steel or cobalt chromium and are expanded by means of a balloon on the tip of the delivery catheter to plastically deform the stent into contact with the vessel wall. In other applications, self-expanding stents are used. These are made of a resilient material that can be collapsed into a compact shape for delivery via catheter and that will self-expand into contact with the vessel when deployed from the catheter. Materials commonly used for self-expanding stents include stainless steel and elastic or superelastic alloys such as nickel titanium (Nitinol™).
• While self-expanding stents have demonstrated promise in various applications, such stents face a number of challenges. One such challenge is that in some cases the disease in a vessel may be so extensive that a stent of very long length, e.g. 30-200 mm, is called for. Currently available stents are typically less than 30 mm in length, and suffer from excessive stiffness if made longer. Such stiffness is particularly problematic in peripheral vessels such as the femoral arteries, where limb movement requires a high degree of flexibility in any stent implanted in such vessels.
• To overcome the stiffness problem, the idea of deploying multiple shorter stents end-to-end has been proposed. However, this approach has suffered from several drawbacks. First, currently available delivery catheters are capable of delivering only a single stent per catheter. In order to place multiple stents, multiple catheters must be inserted, removed and exchanged, heightening risks, lengthening procedure time, raising costs, and causing excessive material waste. In addition, the deployment of multiple stents end-to-end suffers from the inability to accurately control stent placement and the spacing between stents. This results in overlap of adjacent stents and/or excessive space between stents, which is thought to lead to complications such as restenosis, the renarrowing of a vessel following stent placement. With self-expanding stents the problem is particularly acute because as the stent is released from the catheter, its resiliency tends to cause it to eject or “watermelon seed” distally from the catheter tip by an unpredictable distance. During such deployment, the stent may displace not only axially but rotationally relative to the delivery catheter resulting in inaccurate, uncontrollable, and unpredictable stent placement.
• Interleaving stents or stent segments such as those disclosed in co-pending application Ser. No. 10/738,666, filed Dec. 16, 2003, which is incorporated herein by reference, present even greater challenges to conventional delivery systems. Interleaving stents have axially extending elements on each end of the stent that interleave with similar structures on an adjacent stent. Such interleaving minimizes the gap between adjacent stents and increases vessel wall coverage to ensure adequate scaffolding and minimize protrusion of plaque from the vessel wall. However, such interleaving requires that the relative rotational as well as axial positions of the adjacent stents be maintained during deployment to avoid metal overlap and excessive gaps between stents. Conventional delivery systems suffer from the inability to control both the axial and rotational positions of self-expanding stents as they are deployed.
• What are needed, therefore, are stents and stent delivery system that overcome the foregoing problems. In particular, the stents and stent delivery systems should facilitate stenting of long vascular regions of various lengths without requiring the use of multiple catheters. Such stents and delivery systems should also provide sufficient flexibility for use in peripheral vessels and other regions where long and highly flexible stents might be required. In addition, the stents and stent delivery systems should enable the delivery of multiple stents of various lengths to one or more treatment sites using a single catheter without requiring catheter exchanges. Further, the stents and stent delivery systems should facilitate accurate and repeatable control of stent placement and inter-stent spacing to enable deployment of multiple self-expanding stents end-to-end in a vessel at generally constant spacing and without overlap. Moreover, the stents and delivery systems should enable the deployment of interleaving stents or stent segments with precision and control over both the axial spacing and rotational position of each stent or segment.
BRIEF SUMMARY OF THE INVENTION
• The present invention provides prostheses, prosthesis delivery systems, and methods of prosthesis deployment that enable the precise and controllable delivery of multiple prostheses using a single delivery catheter. The prostheses, delivery systems, and methods of the invention provide for the precise control of prosthesis placement so that inter-prosthesis spacing is maintained at a constant and optimum distance. In some embodiments, both axial and rotational displacement of the prostheses relative to the delivery catheter is controlled during deployment, enabling the delivery of multiple prostheses that interleave with one another without overlap. The prostheses, prosthesis delivery systems, and methods of the invention further enable the length of prostheses to be customized in situ to match the length of the site to be treated. The invention is particularly useful for delivery of self-expanding prostheses, but balloon expandable prostheses are also contemplated within the scope of the invention. The invention is well-suited to delivery of stents to the coronary arteries and to peripheral vessels such as the popliteal, femoral, tibial, iliac, renal, and carotid arteries. The invention is further useful for delivery of prostheses to other vessels including biliary, neurologic, urinary, reproductive, intestinal, pulmonary, and others, as well as for delivery of other types of prostheses to various anatomical regions, wherever precise control of prosthesis deployment is desirable.
• In a first aspect of the invention, a prosthesis delivery catheter includes an outer shaft having a first lumen; a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen; a deployment mechanism for deploying a selected number of the prostheses from the first lumen; and a control member interactive with the prostheses to control expansion of the prostheses when the prostheses are deployed from the first lumen.
• The control member may comprise a plurality of axially-extending wires, the prostheses being coupled to the wires and axially slidable thereon, the wires being radially deflectable to allow controlled expansion of the prostheses. The wires may have free distal ends configured to move radially outward as the prostheses expand. The distal ends of the wires may be retractable into the outer shaft following deployment of the selected number of prostheses. The prostheses may have sidewalls with a plurality of openings, the wires being threaded through the openings. The wires may form a loop extending around the outside of the prostheses and through the inside of the prostheses, wherein the wires can be withdrawn from around the prostheses following deployment thereof. In such case, at least one end of each wire is releasable to allow the wire to be withdrawn following prosthesis deployment.
• The delivery catheter may further comprise an inner shaft disposed in the first lumen, the prostheses being slidably disposed around the inner shaft, wherein a distal end of each wire is releasably coupled to the inner shaft. A nosecone may be attached to the inner shaft distally of the prostheses, the distal end of each wire being releasably coupled to the nosecone. The inner shaft may also have an inner lumen and at least one port in communication with the inner lumen, wherein the control wires are slidably disposed through the inner lumen and the port.
• The control member may also comprise a sleeve disposed around the prostheses, the sleeve being expandable to allow controlled expansion of the prostheses. The sleeve may be elastomeric, an expandable mesh or woven material, or other expandable structure. When expanded, the sleeve may form a cone shape that flares in the distal direction. The sleeve may be slidable relative to the outer shaft. The sleeve may have at least one longitudinal slit therein whereby it expands by splitting at the longitudinal slit. The sleeve may have a pair of opposing edges bordering the longitudinal slit, a cone shape being formed by moving the edges at an angle relative to each other. The sleeve may also have a plurality of longitudinal sections or beams separated by longitudinal slits, the longitudinal sections being deflectable outwardly to allow controlled expansion of the prostheses. A retainer may be releasably coupled to the longitudinal sections to selectively prevent radial deflection thereof. The retainer may comprise a capsule coupled to an inner shaft slidably disposed through the first lumen, longitudinal sections being received in the capsule.
• The deployment mechanism of the delivery catheter may comprise a pushing element slidably disposed in the first lumen, the pushing element being in engagement with at least one of the prostheses to advance the prostheses distally relative to the outer shaft. In preferred embodiments, the prostheses are self-expandable, made of resilient or shape memory materials such as stainless steel, Nitinol or suitable polymers. Such self-expanding prostheses are held in an unexpanded state within the outer shaft until deployed therefrom, whereupon they resiliently expand to an expanded shape in contact with the vessel wall or lesion. The delivery systems of the invention will also be useful with balloon expandable prostheses. In either case, expandable balloons, valve members, and other mechanisms may also be included in the delivery catheter to facilitate stent deployment.
• In a further aspect of the invention, the prostheses are releasably interconnected to each other. In this case, the control member may comprise an interconnection structure on the pushing element, the interconnection structure being releasably coupled to at least one of the prostheses to resist distal movement of the prostheses relative to the outer shaft.
• In addition to controlling axial position of the stents relative to the delivery catheter and/or to each other during deployment, the control member of the delivery catheter is preferably configured to maintain rotational position of the prostheses relative to each other. This facilitates the delivery of stents having axially interleaving elements and prevents excessive spacing or overlap between such elements
• In still another aspect of the invention, a prosthesis delivery catheter for delivering prostheses into a vessel lumen comprises an outer shaft having a first lumen; a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen; a deployment mechanism for deploying a selected number of the prostheses from the first lumen; and an anchor member adapted to engage the vessel to limit movement of the outer shaft relative thereto when a prosthesis is being deployed. In one embodiment, the anchor member comprises an expandable member mounted on an inner shaft, the inner shaft being slidably disposed in the first lumen. The expandable member preferably comprises a balloon. The expandable member may be configured to expand within a deployed prosthesis in the vessel lumen. The expandable member is preferably configured to remain expanded within the deployed prosthesis while a second prosthesis is deployed adjacent to the deployed prosthesis. This maintains the relative positions of the deployed prosthesis and the delivery catheter so the second prosthesis is deployed at a predictable distance from the deployed prosthesis.
• In another aspect of the invention, a prosthesis delivery catheter for delivering prostheses into a vessel lumen comprises an outer shaft having a first lumen; a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen, each prosthesis comprising a distal portion and proximal portion, the distal portion being configured to expand into engagement with the vessel while the proximal portion is at least partially disposed in the first lumen; and a deployment mechanism for deploying a selected number of the prostheses from the first lumen. Preferably, the distal portion is configured to engage the vessel prior to deployment of the proximal portion so that the prosthesis remains in a generally constant position relative to the catheter as the proximal portion is deployed.
• In one embodiment, the distal and proximal portions of the prostheses are interconnected by at least one spring member, the spring member having a retracted shape and an elongated shape and being biased into the retracted shape, wherein deployment of the distal portion into the vessel elongates the spring into the elongated shape. In such a case, the deployment of the proximal portion into the vessel allows the spring to return at least partially to the retracted shape to draw the proximal portion toward the distal portion.
• In still another aspect, the invention provides a method of delivering one or more prostheses to a treatment site in a vessel comprising positioning a delivery catheter at the treatment site, the delivery catheter carrying a plurality of self-expanding prostheses; selecting a desired number of the prostheses to deploy; deploying the desired number of prostheses from the delivery catheter into the vessel, each prosthesis expanding into contact with the vessel upon deployment; and controlling the axial displacement of each of the selected number of prostheses relative to the delivery catheter during the deployment thereof.
• In one embodiment, the axial displacement is controlled by an expandable sleeve disposed around the desired number of prostheses. The method may further include retracting the sleeve from around the prostheses after the prostheses have been deployed. The axial displacement may also be controlled by a plurality of wires coupled with the desired number of prostheses. The wires may be threaded through openings in each of the prostheses, and may be retracted from the prostheses after the prostheses have been deployed.
• The method may further include controlling the rotational displacement of the selected number of prostheses relative to the delivery catheter and/or relative to each other during the deployment thereof.
• The axial displacement of the prostheses may be controlled by expanding an expandable member in the vessel during deployment of at least a portion of the desired number of prostheses. Alternatively, the axial displacement may be controlled by first expanding a distal portion of a first of the prostheses into engagement with the vessel while a proximal portion of the first of the prostheses remains in the delivery catheter, then expanding the proximal portion of the first of the prostheses into engagement with the vessel.
• As a further alternative, the prostheses may be releasably interconnected while in the delivery catheter, wherein the axial displacement is controlled by connecting at least one of the prostheses to a restraining member in the delivery catheter. In this case, the selected number of prostheses becomes detached from the prostheses remaining in the delivery catheter upon deployment.
• Further aspects of the nature and advantages of the invention will be apparent from the following detailed description of various embodiments of the invention taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side cut-away view of a prosthesis delivery catheter according to the invention.
• FIG. 2A is a side cross-sectional view of a distal portion of a prosthesis delivery catheter according to the invention in a further embodiment thereof.
• FIG. 2B is a side cross-sectional view of the prosthesis delivery catheter ofFIG. 2A showing the deployment of prostheses in a vessel.
• FIGS. 3A-3C are perspective, side, and end views respectively of a prosthesis coupled to control wires according to further embodiments of the invention.
• FIG. 4A is a side cross-section of a distal portion of a prosthesis delivery catheter according to the invention in a further embodiment thereof.
• FIG. 4B is a side cross-section of the prosthesis delivery catheter ofFIG. 4A showing the deployment of prostheses in a vessel.
• FIG. 5 A is a side cross-section of a distal portion of a prosthesis delivery catheter according to the invention in a further embodiment thereof.
• FIG. 5B is an oblique view of a distal portion of a prosthesis delivery catheter according to the invention in yet another embodiment thereof.
• FIGS. 6A-6C are side cross-sectional views of a distal portion of a prosthesis delivery catheter according to the invention in still another embodiment thereof, showing the outer shaft unretracted, outer shaft retracted with sleeve unexpanded, and sleeve with stents expanded, respectively.
• FIGS. 7A-7B are side cross-sectional views of a distal portion of a prosthesis delivery catheter according to the invention in another embodiment thereof, showing outer shaft retracted with sleeve unexpanded, and outer shaft retracted with sleeve and stents expanded, respectively.
• FIGS. 8A-8C are side cross-sectional views of a distal portion of a prosthesis delivery catheter according to the invention in a further embodiment thereof, showing the outer shaft unretracted, outer shaft retracted with sleeve unexpanded, and sleeve with stents expanded, respectively.
• FIGS. 9A-9B are side cross-sectional views of a distal portion of a prosthesis delivery catheter in a vessel according to the invention in another embodiment thereof, showing outer shaft retracted with prosthesis partially deployed, and prosthesis fully deployed, respectively.
• FIGS. 10A-10B are side cross-sectional views of a distal portion of a prosthesis delivery catheter in a vessel according to the invention in yet another embodiment thereof, showing outer shaft retracted with prosthesis partially deployed, and prosthesis fully deployed, respectively.
• FIGS. 11A-11C are side cross-sectional views of a distal portion of a prosthesis delivery catheter in a vessel according to the invention in yet another embodiment thereof, showing a first prosthesis deployed, an expandable member expanded within the first prosthesis, and a second stent deployed with expandable member expanded in the first prosthesis, respectively.
• FIGS. 11D-11F are side cross-sectional views of a distal portion of a prosthesis delivery catheter according to the invention in another embodiment thereof, showing the delivery catheter prior to stent deployment, the deployment of a first prosthesis in a vessel, and a deployed prosthesis in the vessel, respectively.
• FIG. 12 is a side cross-sectional view of a distal portion of a prosthesis delivery catheter in a vessel according to the invention in still another embodiment thereof, showing a first prosthesis deployed in a lesion.
DETAILED DESCRIPTION OF THE INVENTION
• Referring toFIG. 1, a first embodiment of a prosthesis delivery catheter according to the invention is illustrated.Delivery catheter20 may have any of various constructions, including that described in co-pending application Ser. No. 10/637,713, filed Aug. 8, 2003 (Attorney Docket No. 21629-000340), which is incorporated herein by reference.Delivery catheter20 has ahandle assembly21 and an elongated catheter body22 that includes three concentric tubular shafts all axially slidable relative to one another: anouter shaft24, apusher26, and aninner shaft28.Pusher26 has adistal extension27 to which apusher ring29 is fixed. In a distal region of the catheter body22, aguidewire tube30 extends slidably through aport32 inouter shaft24 and throughpusher ring29 and has adistal end34, to which is mounted a nosecone36 and a stop member38.
• Delivery catheter20 further includes one or more stent expansion control members, which in the illustrated embodiment comprise a plurality ofcontrol wires40. Preferably, one or more pairs ofcontrol wires40 are mounted on opposing sides ofdelivery catheter20, e.g. fourcontrol wires40 offset 90° from each other.Control wires40 are fixed at their proximal ends42 toinner shaft28, and have free distal ends44.
• Outer shaft24 has adistal extremity46 defining afirst lumen48. A plurality ofstents50 are disposed in a collapsed configuration withinfirst lumen48.Stents50 are preferably composed of a resilient material such as stainless steel or Nitinol so as to self-expand from the collapsed configuration to a radially expanded configuration when deployed fromfirst lumen48. Whilestents50 as illustrated have a wave-like or undulating pattern in a plurality of interconnected circumferential members, the pattern illustrated is merely exemplary and the stents of the invention may have any of a variety of strut shapes, patterns, and geometries. From 2 up to 10 or more stents may be carried byouter shaft24. Optionally, avalve member49 is mounted withinfirst lumen48 to facilitate separating thosestents50 to be deployed from those to remain withinouter shaft24, as described in co-pending application Ser. No. 10/412,714, filed Apr. 10, 2003, which is incorporated herein by reference.
• Control wires40 run along the outside ofstents50 or through the interior ofstents50, are threaded through openings in the walls ofstents50 or are otherwise coupled withstents50 to control the deployment thereof, as described more fully below.Control wires40 are composed of a resilient material such as stainless steel, Nitinol, or a suitable polymer, and are preferably generally straight and biased inwardly againstguidewire tube32 or to a position generally parallel to the axial direction. InFIG. 1,outer shaft24 has been retracted to expose a plurality ofstents50 which are partially expanded and remain coupled to or restrained bycontrol wires40, as explained in greater detail below.
• Handleassembly21 has arotatable retraction knob52 coupled to a shaft housing53, to whichouter shaft24 is fixed. By rotatingretraction knob52,outer shaft24 may be retracted proximally relative topusher26 andinner shaft28. Apull ring54 is coupled toinner shaft28, allowinginner shaft28, and hence controlwires40, to be retracted proximally relative toouter shaft24. Aswitch56 engages and disengagespusher26 withouter shaft28, so thatpusher26 either moves withouter shaft24 or remains stationary asouter shaft24 is retracted.Indicia58 on shaft housing53 indicate the extent of retraction ofouter shaft28 by distance, number of stents, or other suitable measure. Other aspects ofhandle assembly21 are described in co-pending application Ser. No. 10/746466, filed Dec. 23, 2003 (Attorney Docket No. 21629-002200), which is incorporated herein by reference. Except as stated otherwise, any of the embodiments of the stent delivery catheter described below may incorporate the features and be otherwise constructed as just described.
• FIGS. 2A-2B illustrate a distal extremity of astent delivery catheter60 according to the invention in a further embodiment thereof. In this embodiment,stents62 have a series of diamond shapedopenings64 in the walls thereof through which a plurality ofcontrol wires66 are threaded.Stents62 have a plurality of axially-extending V-shapedpoints63 on their distal and proximal ends. Thesepoints63 are configured to interleave or nest with thepoints63 on theadjacent stent62, preferably both in the collapsed and expanded configurations. Various suitable interleaving stent geometries are described in co-pending application Ser. No. 10/736,666, filed Dec. 16, 2003, which is incorporated herein by reference. In order to maintain this interleaving, it is important to maintain the relative rotational and axial positions of theadjacent stents62 both before and during deployment. By extending through theopenings64 in each stent,control wires66 keepadjacent stents62 in rotational alignment as they are advanced forward through the catheter and during deployment. Preferably, eachcontrol wire66 is threaded through at least twoopenings64 in eachstent62, one opening64anear the distal end of eachstent62 and oneopening64bnear the proximal end of eachstent62. Alternatively,control wires66 may be threaded through only asingle opening64 or through three ormore openings64 on eachstent62. Preferably, however,control wires66 are threaded so that the distal and proximal ends ofstents64 will expand at a generally uniform rate when released, as described below.
• Control wires66 are constructed of a resilient and flexible metal or polymer with sufficient stiffness to provide controlled resistance to the expansion ofstents62. This stiffness may be selected to allow the desired expansion behavior ofstents62 such that “watermelon seeding” is avoided, inter-stent spacing is maintained, and sufficient stent expansion occurs.Control wires66 may have various cross-sectional geometries, and may be a flat ribbons or blades, round or oval wires, I-beams, or other suitable structures to control stent expansion, maintain spacing and rotational position, and facilitate withdrawal fromstents62 without interference.Control wires66 may be composed of or coated with a lubricious material such as PTFE to reduce friction during removal fromstents62. In other embodiments,control wires66 may have surface features, be wrapped with wire windings, or be coated with “sticky” material to increase friction withstents62. Coatings or surface structures such as scales with one-way frictional effects may also be applied to controlwires66.
• As a further alternative,control wires66 may comprise flexible hollow tubes which are pneumatically or hydraulically controllable to vary their rigidity or stiffness. For example,control wires66 may comprise polymeric tubes that radially contract or flatten and are very flexible when evacuated of fluid, but which become more rigid when filled with pressurized fluid, such as saline, air, or other liquid or gas. In such an embodiment,control wires66 are fluidly connected to a pump, syringe, or other suitable fluid delivery mechanism at the proximal end of the delivery catheter. In this way,control wires66 may be pressurized to increase stiffness asstents62 are deployed, then evacuated of fluid to reduce their profile and stiffness during withdrawal from the deployed stents.
• Stents62 are slidably positioned over aninner shaft68, to which is attached anosecone70 at the distal end of the device. Anouter shaft72 is slidably disposed overinner shaft68 and surroundsstents62, maintaining them in a collapsed configuration, as shown inFIG. 2A. Apusher shaft74 is slidably disposed overinner shaft68 and is configured to engage the proximal end of theproximal-most stent62.Outer shaft72 is retractable relative toinner shaft68 in order to expose a desired number ofstents62 as shown inFIG. 2B. Whenouter shaft72 is retracted, the exposedstents62 self-expand to a larger-diameter expanded shape in engagement with lesion L in vessel V. Preferably, at least the distal end of thedistal-most stent62, and more preferably a substantial portion of allstents62 being deployed, is allowed to expand into engagement with lesion L whilecontrol wires66 remain threaded throughopenings64.Control wires66 are then withdrawn fromopenings62, preferably by holdingcatheter60 in position and pullingcontrol wires66 proximally using a suitable mechanism such as that described above with reference toFIG. 1. Alternatively, theentire catheter60 may be retracted proximally relative tostents62 to withdrawcontrol wires66 fromopenings62. Because at least a portion ofstents62 is in engagement with lesion L,stents62 are held in position in the vessel ascontrol wires66 are withdrawn.
• Optionally,inner shaft68 may have aballoon76 mounted thereto near its distal end to enable pre- or post-dilatation of lesion L. In this embodiment,inner shaft68 has an inflation lumen through which inflation fluid may be delivered toballoon76.Balloon76 is preferably as long as the longest lesion that might be treated usingcatheter60. To dilate lesion L prior to stent deployment, or to further expandstents62 after deployment,outer shaft72 and those ofstents62 remaining therein are retracted relative toinner shaft68 to expose a desired length ofballoon76. The exposed portion ofballoon76 may then be inflated within the lesion L and/or the deployedstents62.
• Following deployment and any post-dilatation,inner shaft68 is retracted intoouter shaft72 while maintaining pressure againstpusher shaft74. This slidesstents62 distally alongcontrol wires66 and repositionsstents62 to the distal end ofinner shaft68 so as to be ready for deployment.Catheter60 may then be repositioned to another vascular location for deployment ofadditional stents62.
• Control wires66 may be coupled tostents62 in various ways, some of which depend upon the configuration ofstents62. For example, as shown in FIGS.3A-B, thepoints63 at the ends of eachstent62 may be bent inwardly such that a portion of theopenings64′ are oriented axially.Control wires66 may then be threaded through these axially-orientedopenings64′. Preferably, upon deployment, points63 are adapted to deform with stent expansion so as to be more parallel to the axial direction, thereby providing a smooth and open flow path through the stent.
• In another embodiment, shown inFIG. 3C,stents80 have axially-alignedeyelets82 through whichcontrol wires84 are threaded. Theseeyelets82 may be in the interior ofstents82 as shown inFIG. 3C, or such eyelets may be on the exterior surface ofstents82, or could be drilled through one or more of the struts ofstents82. Various other structures may also be used for coupling the stents of the invention to control wires, including hooks, channels, holes, sleeves, and others, disposed on the interior, exterior or end surfaces of the stent, or through the struts themselves. Such structures may by integral with stent struts and of the same material, may be attached to the stent struts and be of same or different material, or may be a biodegradable material that erodes and eventually is absorbed into the body following deployment.
• Referring now toFIGS. 4A-4B, in a further embodiment, astent delivery catheter90 has anouter shaft92 slidably disposed over aninner shaft94, and at least one stent96 (shown schematically inFIG. 4A) in a collapsed shape withinouter shaft92. A plurality ofcontrol wires97 have anouter extremity98 outside ofinner shaft94 and aninner extremity100 extending through one ormore lumens102 anddistal ports103 ininner shaft94. Bothouter portion98 andinner portion100 extend proximally to the proximal end ofdelivery catheter90.Outer extremities98 are threaded through openings in the wall ofstent96 or are otherwise coupled thereto as described above so as to resist expansion ofstent96 upon deployment.Control wires97 thus form a continuous loop from the proximal end ofstent delivery catheter90, throughstent96 and back to the proximal end of the catheter.
• FIG. 4B illustrates this embodiment ofdelivery catheter90 positioned in a vessel V and carrying plurality ofstents96′.Stents96′ haveaxial projections104 at their distal and proximal ends configured to interleave whenstents96′ are collapsed withinouter shaft92 and when deployed in vessel V. Whenouter shaft92 is retracted to expose one ormore stents96′, the expansion ofstents96′ can be resisted and controlled by maintaining tension oncontrol wires97. Tension may be controllably relaxed to allowstents96′ to expand into contact with lesion L, as shown inFIG. 4B. By controlling the expansion in this way, the axial spacing and rotational positions ofadjacent stents96′ may be maintained so that gaps and overlaps are minimized and the interleaving ofaxial projections104 is maintained. Whenstents96′ are fully expanded, one end of eachcontrol wire97 may be released at the proximal end ofdelivery catheter90 while the other end is pulled to retract the control wires fromstents96′.
• In a further embodiment, illustrated schematically in FIGS.5A-B,delivery catheter108 is constructed as described above except thatcontrol wires110 are releasably coupled to the distal end of aninner shaft112 or tonose cone114. In an exemplary embodiment,control wires110 haveballs116 at their distal ends configured to be received withinslots118 on the outer surface of nosecone114 (FIG. 5A) or on the proximal face of nosecone114 (FIG. 5B; outer shaft not shown for clarity).Slots118 have anenlarged portion120 of sufficient size to receiveball116 and anarrow portion122 through whichballs116 may not pass.Inner shaft112 is axially rotatable relative to controlwires110. As in the embodiment of FIGS.4A-B, withballs116 held withinslots118, tension may be maintained oncontrol wires110 to resist expansion ofstent124.Stent124 may be allowed to expand by gradually relaxing tension oncontrol wires110. Oncestent124 is fully expanded tension oncontrol wires110 may be fully relaxed andnosecone114 then rotated by rotatinginner shaft112, thereby allowingballs116 to pass throughenlarged portions120.Control wires110 may then be withdrawn from the deployedstent124.Nosecone114 is then retracted orcontrol wires110 advanced so as to reinsertballs116 intoslots118.Nosecone114 is then rotated to alignballs116 withnarrow portions122, again securing the control wires tonosecone114.Delivery catheter108 may then be repositioned to deploy additional stents.
• Optionally,delivery catheter108 may include a middle shaft orballoon126 over whichstents124 are positioned, as shown inFIG. 5A. In this case,inner shaft112 is slidably and rotatably disposed in an inner lumen though middle shaft orballoon126. If a balloon is included, it may be used for pre-dilatation of lesions prior to stent deployment, or for further expansion ofstent124 following deployment.
• In the foregoing embodiment,control wires110 will be constructed to have sufficient stiffness to resist rotation, twisting or bending asnosecone114 is rotated to releasecontrol wires110. Maintaining some tension oncontrol wires110 asnosecone114 is rotated may facilitate the release process. In addition,control wires110 will have sufficient column strength to facilitate reinsertion intoslots118 following deployment ofstents124. Thus the size, material and geometry ofcontrol wires110 will be selected to enable these actions while providing the desired level of control of stent expansion.
• In a further embodiment of a stent delivery catheter according to the invention, anexpandable sleeve130 is slidably positioned withinouter shaft132 and carriesstents134 as shown in FIGS.6A-C.A pusher shaft136 is slidable withinsleeve130 and engages theproximal-most stent134. Aninner shaft138 extends throughpusher shaft136 and has anosecone140 fixed to its distal end.Sleeve130, or at least a distal extremity thereof, may be a tube constructed of a resilient deformable material such as urethane or other medical grade elastomer, or may be a tubular mesh, cage, grating, or other suitable structure of flexible and resilient polymer or metal such as stainless steel or Nitinol. The elasticity and stiffness ofsleeve130 are selected to allowstents134 to expand at the desired rate when deployed fromouter shaft132 without excessive axial or rotational displacement relative to each other or toouter shaft132.Sleeve130 is resiliently biased toward an unexpanded shape so that following stent deployment,sleeve130 returns to a generally tubular shape.Outer shaft132 is constructed of a material with sufficient radial strength and stiffness to resist expansion ofstents134 andsleeve130, and may include a metallic or polymeric braid, ribs, rings or other structural reinforcement near its distal end for such purpose.
• The interior surface ofsleeve130 optionally may have surface features such as bumps, scales, bristles, ribs, or roughness to enhance friction withstents134. These features may be configured to have a grain such that they provide more friction against movement in the distal direction than in the proximal direction, or vice versa. Further, such features may be adapted to provide more friction whensleeve130 is in an unexpanded shape than when it is expanded bystents134. For example, bristles may be provided that point more in the proximal direction whensleeve130 is in its unexpanded cylindrical shape, but which point more distally or radially (perpendicular to the surface of sleeve130) whensleeve130 is expanded. This allowssleeve130 to be more easily withdrawn fromstents134 whenstents134 are deployed.
• In order to deploystents134,delivery catheter129 is positioned across a vascular lesion so thatnosecone140 is disposed just distally of the distal end of the lesion.Outer shaft132 is then retracted to expose the desired number of stents134 (and the associated length of sleeve130) which will cover the length of the lesion, as shown inFIG. 6B. Asouter shaft132 is retracted,stents134 are allowed to expand into contact with the lesion as shown inFIG. 6C.Sleeve130 controls the rate of expansion and maintains the positions ofstents134 so they are deployed precisely at the intended location. Oncestents134 are fully expanded,sleeve130 may be retracted from between the stents and the lesion untilsleeve130 is again disposed inouter shaft132. Pressure is maintained onpusher shaft136 during this process so that thestents134 remaining indelivery catheter129 are advanced to the distal end ofsleeve130 andouter shaft132.Delivery catheter129 may then be repositioned for deployment of additional stents at other locations.
• Referring now to FIGS.7A-B, in a further embodiment, adelivery catheter142 may be constructed largely as described in connection with FIGS.6A-C, including anouter shaft144, anexpandable sleeve146 slidably disposed therein, apusher shaft148, andinner shaft150. A plurality ofstents152 are carried in expandable sleeve146 (shown inFIG. 7B). In order to facilitate expansion,expandable sleeve146 includes a longitudinal slit154 in at least a distal extremity thereof. Whenouter shaft144 is retracted relative tosleeve146,sleeve146 may be controllably expanded by axially twistingsleeve146 such that the opposingedges156 along longitudinal slit154 pivot away from one another, forming a cone shape (FIG. 7B). In this way, the expansion ofstents152 is further controllable after retraction ofouter shaft144 by controlling the rate of twisting ofsleeve146. An actuator may be provided at the proximal end ofdelivery catheter142 to control such twisting. Optionally,sleeve146 may have a helical thread on its outer surface that mates with a complementary thread on the interior ofouter shaft144 such thatsleeve146 is automatically twisted asouter shaft144 is retracted. As in the embodiment of FIGS.6A-C, following stent deployment,sleeve146 is retracted from the space between the deployed stents and the vessel wall and returned withinouter shaft144.Sleeve146 may be resiliently biased to return to its unexpanded configuration, or may be manually twisted back to an unexpanded shape by the operator.
• In another embodiment, shown in FIGS.8A-C,delivery catheter160 is again constructed much likedelivery catheter129 of FIGS.6A-C, including anouter shaft162, a slidableexpandable sleeve164 carryingstents166, apusher shaft168, and aninner shaft170. Anosecone172 is attached to the distal end ofinner shaft170 and has aconcavity174 at its proximal end configured to receive the distal end ofsleeve164. A distal extremity ofsleeve164 includes a plurality ofaxial slits176 defining separate deflectablelongitudinal beams178.Sleeve164 includes at least two, preferably four, and as many as six, eight, ormore slits176 to provide a corresponding number oflongitudinal beams178.Longitudinal beams178 are resiliently biased into an axial orientation whereinsleeve164 is generally cylindrical.Longitudinal beams178 have sufficient stiffness against lateral deflection to resist and control the expansion ofstents166.
• Advantageously, by containing the distal ends oflongitudinal beams178 inconcavity174,outer shaft162 may be retracted to expose the desired number of stents to cover a target lesion without immediate expansion ofstents166, as shown inFIG. 8B. When the desired number ofstents166 is exposed,inner shaft170 may be advanced distally relative tosleeve164, releasinglongitudinal beams178 fromconcavity174. This permitslongitudinal beams178 to laterally deflect, allowingstents166 to expand, as shown inFIG. 8C. When full expansion is achieved,longitudinal beams178 may be retracted from betweenstents166 and the vessel wall.Longitudinal beams178 then return to their undeflected axial orientation, allowinginner shaft170 to be retracted so as to return the distal ends oflongitudinal beams178 intoconcavity174.Inner shaft170 andsleeve164 may then be retracted intoouter shaft162 while maintaining pressure onpusher shaft168, thereby advancingadditional stents166 toward the distal end ofsleeve164 for additional deployments.
• In some embodiments of the stent delivery catheter of the invention, the stents themselves are configured to provide greater control and precision in stent deployment. For example,FIGS. 9A-9B illustrates adelivery catheter180 having a plurality ofstents182 disposed in anouter shaft184. Aninner shaft186 withoptional balloon188 andnosecone190 extends throughouter shaft184 andstents182 and is axially movable relative thereto. A pusher shaft (not shown) is slidably disposed overinner shaft186 and engagesstents182 for purposes of deployingstents182 fromouter shaft186 and repositioning the remainingstents182 withinouter shaft186, as in earlier embodiments. In this embodiment,stents182 comprise a plurality ofstruts191 forming a series ofrings192 interconnected atjoints193. Eachring192 has a series ofclosed cells194 interconnected circumferentially and having an “I” shape in the unexpanded configuration.
• Asouter shaft184 is retracted to deploy one ormore stents182, at least adistal ring192′ is configured to expand into engagement with the vessel wall before the entire length of thestent182 is deployed from outer shaft184 (FIG. 9A). Once in engagement with the lesion L in vessel V,distal ring192′anchors stent182 in position as the remainder of the stent is deployed (FIG. 9B), preventing “watermelon seeding” of the stent from the catheter. The axial length ofstent182, the length of eachring192, the number of rings, the stiffness ofstruts191, and the flexibility ofjoints193 are all selected to optimize this deployment behavior. Eachstent182 has at least two, and preferably four ormore rings192, each ring being about 2-5 mm in length, givingstent182 an overall length of at least about 8-20 mm. Of course, stents of shorter or longer length are also contemplated within the scope of the invention. Lesions longer than eachstent182 may be treated by deployingmultiple stents182 end-to-end. Advantageously, eachstent182 can be deployed precisely at a desired spacing from a previously-deployedstent182 because thedistal ring192′ of eachstent182 can be first allowed to expand into engagement with the vessel at the target location, anchoring the stent in position as the remainder is deployed.
• Rings192 are preferably formed from a common piece of material and are integrally interconnected atjoints193, makingjoints193 relatively rigid. In this embodiment, the majority of flexibility betweenrings192 is provided bystruts191 rather than byjoints193. Alternatively, joints193 may comprise welded connections betweenrings192 which are also fairly rigid. As a further alternative,joints193 may comprise hinge or spring structures to allow greater deflection betweenadjacent rings192, as exemplified inFIGS. 10A-10B, described below.
• In the embodiment ofFIG. 10A-10B,stents200 are constructed similarly tostents182 ofFIGS. 9A-9B, including a plurality ofinterconnected rings202 having I-shapedcells204. However, in this embodiment, some ofrings202 are interconnected byspring members206 that may be elongated to increase the distance betweenrings202 and that are resiliently biased into a shortened configuration to drawrings202 toward each other. In one embodiment,spring members206 have a wave-like shape and extend from the tip of anaxial projection208 on onering202 to aconcave portion210 betweenaxial projections208 on theadjacent ring202. Of course a variety of spring configurations and connection locations are possible, including zig-zags, coils, spirals, accordian or telescoping structures, and the like. Further, resilient elongatable elastomeric elements may link the adjacent rings202. In the illustrated embodiment,stent200 comprises two pairs ofrings202, with the rings of each pair interconnected byintegral joints212 as in FIGS.9A-B and the pairs ofrings202 being connected to each other byspring members206.Stents200 may alternatively include two, three, five, six ormore rings202, andspring members206 may interconnect all or only a portion ofrings202.
• Spring members206 may be formed of the same or different material as that ofrings202, depending upon the desired performance characteristics. In addition,spring members206 may be biodegradable so as to erode and eventually disappear, leaving the adjacent pairs ofrings202 unconnected.
• During deployment, asouter shaft184 is retracted to expose astent200, the distal pair ofrings202′ first expands into engagement with lesion L in vessel V (FIG. 10A).Spring members206 elongate to allowrings202′ to fully expand without pulling the second pair ofrings202″ fromouter shaft184. As retraction ofouter shaft184 continues, the second pair ofrings202″ expands and simultaneously is drawn towarddistal ring pair182′ by contraction of spring members206 (FIG. 10B). This results in a predictable and constant axial spacing between the adjacent pairs ofrings202. In addition,spring members206 maintain rotational alignment ofrings202 to maintain the interleaving ofaxial projections208 without overlap. As in previous embodiments,multiple stents200 may be deployed sequentially fromdelivery catheter180 to cover longer lesions. The ability to precisely deploy each stent permits the relative axial spacing and rotational position of such stents to be controlled to avoid excessive space or overlap.
• In a further embodiment, shown schematically inFIGS. 11A-11C, adelivery catheter216 has anouter shaft218 carrying a plurality ofstents220. Aninner shaft222 extends throughouter shaft218 to anosecone224, and apusher shaft226 is slidably disposed overinner shaft222. An anchoringballoon228 is mounted toinner shaft222 proximal tonosecone224. Anchoringballoon228 has an axial length sufficient to frictionally engage the wall of vessel V and remain stable so as to anchordelivery catheter216 in place as further described below. Preferably, anchoringballoon228 has a length about equal to the length of one ofstents220.
• In use,outer shaft218 is retracted so that afirst stent220′ is released therefrom and expands into engagement with lesion L (FIG. 11A). Anchoringballoon228 is then inflated until it engages the interior ofstent220′ (FIG. 11B). This not only stabilizesdelivery catheter216, but may be used to further expandstent220′ and/or dilate lesion L to firmly implantstent220′. While keeping anchoring balloon inflated withinstent220′,outer shaft218 is further retracted to release asecond stent220″, which expands into engagement with lesion L (FIG. 11C). Advantageously, anchoringballoon228 stabilizesdelivery catheter216 and anchors it in position relative tofirst stent220′ assecond stent220″ is deployed.Second stent220″ is thus deployable precisely at the intended spacing and rotational position relative tofirst stent220′. Anchoringballoon228 may then be deflated and retracted intoouter shaft218, with pressure maintained uponpusher shaft226 to reposition remainingstents220 at the distal end ofinner shaft222.
• FIGS. 11D-11F illustrate another embodiment of adelivery catheter219 in which a plurality of self-expandingstents221 are slidably disposed over anelongated balloon223.Balloon223 preferably has a length as long as the longest lesion that is to be treated with the device, e.g. 50-200 mm. Apusher225 is slidable relative to balloon223 and has a tubulardistal portion227 disposed overballoon223 which engages theproximal-most stent221P. Asheath229 is slidably disposed overpusher225,stents221 andballoon223 and maintainsstents221 in a radially contracted configuration. In this embodiment, moderate pressure is maintained withinballoon223 during deployment ofstents221 so that the balloon expands simultaneously with each stent. As shown inFIG. 11B, assheath229 is retracted, afirst stent221A and a distal portion ofballoon223 are exposed. By maintaining moderate inflation pressure inballoon223 assheath220 is retracted the exposed portion ofballoon223 expands with thefirst stent221A, inhibiting distal migration of the stent fromdelivery catheter219. One or moreadditional stents221 may be deployed by further retraction ofsheath229, during whichballoon223 remains expanded withinfirst stent221 anchoring thedelivery catheter219 in position (not shown). As each additional stent is exposed fromsheath229, the pressure inballoon223 causes it to expand with the stent so as to control its rotational and axial position. Of course,stents221 may have any of a variety of different configurations, including having open or closed cells, zig-zag or wave-shaped struts, and/or axially interleaving elements as described above.
• Optionally,balloon223 may have surface features or coatings on its periphery that enhance retention ofstents221 thereon. Such features may include structures such as scales or protuberances that are activated by pressurization of the balloon so that retention is lessened when the balloon is deflated, but heightened when the balloon is pressurized. Following stent deployment, pressure can optionally be increased inballoon223 for post-dilation ofstents221 and the targetlesion L. Balloon223 is then deflated and retracted withinsheath229 as distal pressure is maintained againstpusher225, repositioningstents221 near the distal end ofballoon223 withinsheath229 for deployment at another location, as shown inFIG. 11C.
• In a further embodiment, the stents in the delivery catheter of the invention may releasably interconnect with one another and/or with the pusher shaft to enable greater control and precision during deployment. As illustrated inFIG. 12,delivery catheter230 carries a plurality ofstents232 having a structure much like that described above in connection withFIGS. 9A-9B. However, in this embodiment, theaxial projections234 extending distally and proximally fromstents232 are configured to interconnect withconcavities236 onadjacent stents232 until expanded. In one embodiment,axial projections234 have enlargedheads246 andconcavities236 havenecks248 that retainheads246 withinconcavities236 in the unexpanded configuration.Pusher shaft250 has adistal end252 havingprojections254 andconcavities256 like those ofstents232, thus being able to interconnect with theproximal-most stent232′. When astent232″ expands, the interconnecting structures thereon are configured to separate from the adjacent stent or pusher shaft, thus releasing the deployedstent232″ fromdelivery catheter230. In the example shown, asstent232″ expands, heads246″ contract in size whilenecks248″ enlarge, thereby allowingheads246″ on the expanded stent to be released fromconcavities236 in the adjacent unexpanded stent, and vice versa. By exerting traction onpusher shaft250 during the deployment process, the line ofstents232 is kept from moving distally relative toouter shaft231, thus preventing the deployedstent232″ from “watermelon seeding” as it expands.
• Various types of interconnecting structures between adjacent stents and between the stents and the pusher shaft are possible within the scope of the invention, including those described in co-pending application Ser. No. 10/738,666, filed Dec. 16, 2003, which is incorporated herein by reference. Such interconnecting structures may also be breakable or frangible to facilitate separation as the stent expands. In addition, a mechanism such as an expandable balloon or cutting device may be disposed at the distal end ofdelivery catheter230 to assist in separatingstents232 upon deployment. Further, the interconnections between stents may be different than the interconnection between the proximal-most stent and the pusher shaft. For example, the pusher shaft may have hooks, magnets, or other mechanisms suitable for releasably holding and maintaining traction on the proximal end of a stent until it is deployed.
• While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, improvements and additions are possible without departing from the scope thereof, which is defined by the claims.

Claims (45)

1. A prosthesis delivery catheter comprising:

an outer shaft having a first lumen;

a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen;

a deployment mechanism for deploying a selected number of the prostheses from the first lumen; and

a control member interactive with the prostheses to control expansion of the prostheses when the prostheses are deployed from the first lumen.

2. The prosthesis delivery catheter ofclaim 1 wherein the control member comprises a plurality of axially-extending wires, the prostheses being coupled to the wires and axially slidable thereon, the wires being radially deflectable to allow controlled expansion of the prostheses.

3. The prosthesis delivery catheter ofclaim 2 wherein the wires have free distal ends configured to move radially outward as the prostheses expand.

4. The prosthesis delivery catheter ofclaim 3 wherein the distal ends are retractable into the outer shaft following deployment of the selected number of prostheses.

5. The prosthesis delivery catheter ofclaim 2 wherein the prostheses have sidewalls with a plurality of openings, the wires being threaded through the openings.

6. The prosthesis delivery catheter ofclaim 2 wherein the wires form a loop extending around the outside of the prostheses and through the inside of the prostheses.

7. The prosthesis delivery catheter ofclaim 6 wherein the wires can be withdrawn from around the prostheses following deployment thereof.

8. The prosthesis delivery catheter ofclaim 7 wherein at least one end of each wire is releasable to allow the wire to be withdrawn following prosthesis deployment.

9. The prosthesis delivery catheter ofclaim 8 further comprising an inner shaft disposed in the first lumen, the prostheses being slidably disposed around the inner shaft, wherein a distal end of each wire is releasably coupled to the inner shaft.

10. The prosthesis delivery catheter ofclaim 9 further comprising a nosecone attached to the inner shaft distally of the prostheses, the distal end of each wire being releasably coupled to the nosecone.

11. The prosthesis delivery catheter ofclaim 9 wherein the inner shaft has an inner lumen and at least one port in communication with the inner lumen, the wires being slidably disposed through the inner lumen and the port.

12. The prosthesis delivery catheter ofclaim 1 wherein the control member comprises a sleeve disposed around the prostheses, the sleeve being expandable to allow controlled expansion of the prostheses.

13. The prosthesis delivery catheter ofclaim 12 wherein the sleeve is elastomeric.

14. The prosthesis delivery catheter ofclaim 12 wherein the sleeve is slidable relative to the outer shaft.

15. The prosthesis delivery catheter ofclaim 12 wherein the sleeve has at least one longitudinal slit therein, the sleeve expanding by splitting at the longitudinal slit.

16. The prosthesis delivery catheter ofclaim 15 wherein the sleeve comprises a plurality of longitudinal sections separated by longitudinal slits, the longitudinal sections being deflectable outwardly to allow controlled expansion of the prostheses.

17. The prosthesis delivery catheter ofclaim 16 further comprising a retainer releasably coupled to the longitudinal sections to selectively prevent radial deflection thereof.

18. The prosthesis delivery catheter ofclaim 17 further comprising an inner shaft slidably disposed through the first lumen and having a distal end, the retainer being coupled to the distal end.

19. The prosthesis delivery catheter ofclaim 15 wherein the sleeve expands by forming a cone shape that flares in the distal direction.

20. The prosthesis delivery catheter ofclaim 19 wherein the sleeve has a pair of opposing edges bordering the longitudinal slit, the cone shape being formed by moving the edges at an angle relative to each other.

21. The prosthesis delivery catheter ofclaim 1 wherein the deployment mechanisms comprises a pushing element slidably disposed in the first lumen, the pushing element being in engagement with at least one of the prostheses to advance the prostheses distally relative to the outer shaft.

22. The prosthesis delivery catheter ofclaim 21 wherein the plurality of prostheses are releasably interconnected to each other.

23. The prosthesis delivery catheter ofclaim 22 wherein the control member comprises an interconnection structure on the pushing element, the interconnection structure being releasably coupled to at least one of the prostheses to resist distal movement of the prostheses relative to the outer shaft.

24. The prosthesis delivery catheter ofclaim 1 wherein the control member is configured to maintain rotational position of the prostheses relative to each other.

25. A prosthesis delivery catheter for delivering prostheses into a vessel lumen comprising:

an outer shaft having a first lumen;

a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen;

a deployment mechanism for deploying a selected number of the prostheses from the first lumen; and

a anchor member adapted to engage the vessel to limit movement of the outer shaft relative thereto when a prosthesis is being deployed.

26. The prosthesis delivery catheter ofclaim 25 wherein the anchor member comprises an expandable member mounted on an inner shaft, the inner shaft being slidably disposed in the first lumen.

27. The prosthesis delivery catheter ofclaim 26 wherein expandable member comprises a balloon.

28. The prosthesis delivery catheter ofclaim 26 wherein the expandable member is configured to expand within a deployed prosthesis in the vessel lumen.

29. The prosthesis delivery catheter ofclaim 28 wherein the expandable member is configured to remain expanded within the deployed prosthesis while a second prosthesis is deployed adjacent to the deployed prosthesis.

30. A prosthesis delivery catheter for delivering prostheses into a vessel lumen comprising:

an outer shaft having a first lumen;

a plurality of self-expanding tubular prostheses carried within the first lumen, the prostheses being adapted to radially expand upon deployment from the first lumen, each prosthesis comprising a distal portion and proximal portion, the distal portion being configured to expand into engagement with the vessel while the proximal portion is at least partially disposed in the first lumen; and

a deployment mechanism for deploying a selected number of the prostheses from the first lumen.

31. The prosthesis delivery catheter ofclaim 30 wherein the distal and proximal portions are interconnected by at least one spring member, the spring member having a retracted shape and an elongated shape and being biased into the retracted shape, wherein deployment of the distal portion into the vessel elongates the spring into the elongated shape.

32. The prosthesis delivery catheter ofclaim 31 wherein deployment of the proximal portion into the vessel allows the spring to return at least partially to the retracted shape to draw the proximal portion toward the distal portion.

33. The prosthesis delivery catheter ofclaim 30 wherein the distal portion is configured to engage the vessel prior to deployment of the proximal portion so that the prosthesis remains in a generally constant position relative to the catheter as the proximal portion is deployed.

34. A method of delivering one or more prostheses to a treatment site in a vessel comprising:

positioning a delivery catheter at the treatment site, the delivery catheter carrying a plurality of self-expanding prostheses;

selecting a desired number of the prostheses to deploy;

deploying the desired number of prostheses from the delivery catheter into the vessel, each prosthesis expanding into contact with the vessel upon deployment; and

controlling the axial displacement of each of the selected number of prostheses relative to the delivery catheter during the deployment thereof.

35. The method ofclaim 34 wherein the axial displacement is controlled by an expandable sleeve disposed around the desired number of prostheses.

36. The method ofclaim 35 further comprising retracting the sleeve from around the prostheses after the prostheses have been deployed.

37. The method ofclaim 34 wherein the axial displacement is controlled by a plurality of wires coupled with the desired number of prostheses.

38. The method ofclaim 37 further comprising retracting the wires from the prostheses after the prostheses have been deployed.

39. The method ofclaim 37 wherein the wires are threaded through openings in each of the prostheses.

40. The method ofclaim 34 further comprising controlling the rotational displacement of the selected number of prostheses relative to the delivery catheter during the deployment thereof.

41. The method ofclaim 34 wherein the axial displacement is controlled by expanding an expandable member in the vessel during deployment of at least a portion of the desired number of prostheses.

42. The method ofclaim 34 wherein the axial displacement is controlled by expanding a distal portion of a first of the prostheses into engagement with the vessel while a proximal portion of the first of the prostheses remains in the delivery catheter, then expanding the proximal portion of the first of the prostheses into engagement with the vessel.

43. The method ofclaim 34 wherein the prostheses are releasably interconnected while in the delivery catheter.

44. The method ofclaim 43 wherein the axial displacement is controlled by connecting at least one of the prostheses to a restraining member in the delivery catheter.

45. The method ofclaim 43 wherein the selected number of prostheses detach from the prostheses remaining in the delivery catheter upon deployment.

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