Devices and methods for controlling expandable prostheses during deployment
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.
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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 INVENTIONThe 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
Referring to
Delivery catheter 20 further includes one or more stent expansion control members, which in the illustrated embodiment comprise a plurality of control wires 40. Preferably, one or more pairs of control wires 40 are mounted on opposing sides of delivery catheter 20, e.g. four control wires 40 offset 90° from each other. Control wires 40 are fixed at their proximal ends 42 to inner shaft 28, and have free distal ends 44.
Outer shaft 24 has a distal extremity 46 defining a first lumen 48. A plurality of stents 50 are disposed in a collapsed configuration within first lumen 48. Stents 50 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 from first lumen 48. While stents 50 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 by outer shaft 24. Optionally, a valve member 49 is mounted within first lumen 48 to facilitate separating those stents 50 to be deployed from those to remain within outer shaft 24, as described in co-pending application Ser. No. 10/412,714, filed Apr. 10, 2003, which is incorporated herein by reference.
Control wires 40 run along the outside of stents 50 or through the interior of stents 50, are threaded through openings in the walls of stents 50 or are otherwise coupled with stents 50 to control the deployment thereof, as described more fully below. Control wires 40 are composed of a resilient material such as stainless steel, Nitinol, or a suitable polymer, and are preferably generally straight and biased inwardly against guidewire tube 32 or to a position generally parallel to the axial direction. In
Handle assembly 21 has a rotatable retraction knob 52 coupled to a shaft housing 53, to which outer shaft 24 is fixed. By rotating retraction knob 52, outer shaft 24 may be retracted proximally relative to pusher 26 and inner shaft 28. A pull ring 54 is coupled to inner shaft 28, allowing inner shaft 28, and hence control wires 40, to be retracted proximally relative to outer shaft 24. A switch 56 engages and disengages pusher 26 with outer shaft 28, so that pusher 26 either moves with outer shaft 24 or remains stationary as outer shaft 24 is retracted. Indicia 58 on shaft housing 53 indicate the extent of retraction of outer shaft 28 by distance, number of stents, or other suitable measure. Other aspects of handle assembly 21 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.
Control wires 66 are constructed of a resilient and flexible metal or polymer with sufficient stiffness to provide controlled resistance to the expansion of stents 62. This stiffness may be selected to allow the desired expansion behavior of stents 62 such that “watermelon seeding” is avoided, inter-stent spacing is maintained, and sufficient stent expansion occurs. Control wires 66 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 from stents 62 without interference. Control wires 66 may be composed of or coated with a lubricious material such as PTFE to reduce friction during removal from stents 62. In other embodiments, control wires 66 may have surface features, be wrapped with wire windings, or be coated with “sticky” material to increase friction with stents 62. Coatings or surface structures such as scales with one-way frictional effects may also be applied to control wires 66.
As a further alternative, control wires 66 may comprise flexible hollow tubes which are pneumatically or hydraulically controllable to vary their rigidity or stiffness. For example, control wires 66 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 wires 66 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 wires 66 may be pressurized to increase stiffness as stents 62 are deployed, then evacuated of fluid to reduce their profile and stiffness during withdrawal from the deployed stents.
Stents 62 are slidably positioned over an inner shaft 68, to which is attached a nosecone 70 at the distal end of the device. An outer shaft 72 is slidably disposed over inner shaft 68 and surrounds stents 62, maintaining them in a collapsed configuration, as shown in
Optionally, inner shaft 68 may have a balloon 76 mounted thereto near its distal end to enable pre- or post-dilatation of lesion L. In this embodiment, inner shaft 68 has an inflation lumen through which inflation fluid may be delivered to balloon 76. Balloon 76 is preferably as long as the longest lesion that might be treated using catheter 60. To dilate lesion L prior to stent deployment, or to further expand stents 62 after deployment, outer shaft 72 and those of stents 62 remaining therein are retracted relative to inner shaft 68 to expose a desired length of balloon 76. The exposed portion of balloon 76 may then be inflated within the lesion L and/or the deployed stents 62.
Following deployment and any post-dilatation, inner shaft 68 is retracted into outer shaft 72 while maintaining pressure against pusher shaft 74. This slides stents 62 distally along control wires 66 and repositions stents 62 to the distal end of inner shaft 68 so as to be ready for deployment. Catheter 60 may then be repositioned to another vascular location for deployment of additional stents 62.
Control wires 66 may be coupled to stents 62 in various ways, some of which depend upon the configuration of stents 62. For example, as shown in FIGS. 3A-B, the points 63 at the ends of each stent 62 may be bent inwardly such that a portion of the openings 64′ are oriented axially. Control wires 66 may then be threaded through these axially-oriented openings 64′. Preferably, upon deployment, points 63 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 in
Referring now to
In a further embodiment, illustrated schematically in FIGS. 5A-B, delivery catheter 108 is constructed as described above except that control wires 110 are releasably coupled to the distal end of an inner shaft 112 or to nose cone 114. In an exemplary embodiment, control wires 110 have balls 116 at their distal ends configured to be received within slots 118 on the outer surface of nosecone 114 (
Optionally, delivery catheter 108 may include a middle shaft or balloon 126 over which stents 124 are positioned, as shown in
In the foregoing embodiment, control wires 110 will be constructed to have sufficient stiffness to resist rotation, twisting or bending as nosecone 114 is rotated to release control wires 110. Maintaining some tension on control wires 110 as nosecone 114 is rotated may facilitate the release process. In addition, control wires 110 will have sufficient column strength to facilitate reinsertion into slots 118 following deployment of stents 124. Thus the size, material and geometry of control wires 110 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, an expandable sleeve 130 is slidably positioned within outer shaft 132 and carries stents 134 as shown in FIGS. 6A-C. A pusher shaft 136 is slidable within sleeve 130 and engages the proximal-most stent 134. An inner shaft 138 extends through pusher shaft 136 and has a nosecone 140 fixed to its distal end. Sleeve 130, 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 of sleeve 130 are selected to allow stents 134 to expand at the desired rate when deployed from outer shaft 132 without excessive axial or rotational displacement relative to each other or to outer shaft 132. Sleeve 130 is resiliently biased toward an unexpanded shape so that following stent deployment, sleeve 130 returns to a generally tubular shape. Outer shaft 132 is constructed of a material with sufficient radial strength and stiffness to resist expansion of stents 134 and sleeve 130, and may include a metallic or polymeric braid, ribs, rings or other structural reinforcement near its distal end for such purpose.
The interior surface of sleeve 130 optionally may have surface features such as bumps, scales, bristles, ribs, or roughness to enhance friction with stents 134. 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 when sleeve 130 is in an unexpanded shape than when it is expanded by stents 134. For example, bristles may be provided that point more in the proximal direction when sleeve 130 is in its unexpanded cylindrical shape, but which point more distally or radially (perpendicular to the surface of sleeve 130) when sleeve 130 is expanded. This allows sleeve 130 to be more easily withdrawn from stents 134 when stents 134 are deployed.
In order to deploy stents 134, delivery catheter 129 is positioned across a vascular lesion so that nosecone 140 is disposed just distally of the distal end of the lesion. Outer shaft 132 is then retracted to expose the desired number of stents 134 (and the associated length of sleeve 130) which will cover the length of the lesion, as shown in
Referring now to FIGS. 7A-B, in a further embodiment, a delivery catheter 142 may be constructed largely as described in connection with FIGS. 6A-C, including an outer shaft 144, an expandable sleeve 146 slidably disposed therein, a pusher shaft 148, and inner shaft 150. A plurality of stents 152 are carried in expandable sleeve 146 (shown in
In another embodiment, shown in FIGS. 8A-C, delivery catheter 160 is again constructed much like delivery catheter 129 of FIGS. 6A-C, including an outer shaft 162, a slidable expandable sleeve 164 carrying stents 166, a pusher shaft 168, and an inner shaft 170. A nosecone 172 is attached to the distal end of inner shaft 170 and has a concavity 174 at its proximal end configured to receive the distal end of sleeve 164. A distal extremity of sleeve 164 includes a plurality of axial slits 176 defining separate deflectable longitudinal beams 178. Sleeve 164 includes at least two, preferably four, and as many as six, eight, or more slits 176 to provide a corresponding number of longitudinal beams 178. Longitudinal beams 178 are resiliently biased into an axial orientation wherein sleeve 164 is generally cylindrical. Longitudinal beams 178 have sufficient stiffness against lateral deflection to resist and control the expansion of stents 166.
Advantageously, by containing the distal ends of longitudinal beams 178 in concavity 174, outer shaft 162 may be retracted to expose the desired number of stents to cover a target lesion without immediate expansion of stents 166, as shown in
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,
As outer shaft 184 is retracted to deploy one or more stents 182, at least a distal ring 192′ is configured to expand into engagement with the vessel wall before the entire length of the stent 182 is deployed from outer shaft 184 (
Rings 192 are preferably formed from a common piece of material and are integrally interconnected at joints 193, making joints 193 relatively rigid. In this embodiment, the majority of flexibility between rings 192 is provided by struts 191 rather than by joints 193. Alternatively, joints 193 may comprise welded connections between rings 192 which are also fairly rigid. As a further alternative, joints 193 may comprise hinge or spring structures to allow greater deflection between adjacent rings 192, as exemplified in
In the embodiment of
Spring members 206 may be formed of the same or different material as that of rings 202, depending upon the desired performance characteristics. In addition, spring members 206 may be biodegradable so as to erode and eventually disappear, leaving the adjacent pairs of rings 202 unconnected.
During deployment, as outer shaft 184 is retracted to expose a stent 200, the distal pair of rings 202′ first expands into engagement with lesion L in vessel V (
In a further embodiment, shown schematically in
In use, outer shaft 218 is retracted so that a first stent 220′ is released therefrom and expands into engagement with lesion L (
Optionally, balloon 223 may have surface features or coatings on its periphery that enhance retention of stents 221 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 in balloon 223 for post-dilation of stents 221 and the target lesion L. Balloon 223 is then deflated and retracted within sheath 229 as distal pressure is maintained against pusher 225, repositioning stents 221 near the distal end of balloon 223 within sheath 229 for deployment at another location, as shown in
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 in
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 of delivery catheter 230 to assist in separating stents 232 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
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 of claim 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 of claim 2 wherein the wires have free distal ends configured to move radially outward as the prostheses expand.
4. The prosthesis delivery catheter of claim 3 wherein the distal ends are retractable into the outer shaft following deployment of the selected number of prostheses.
5. The prosthesis delivery catheter of claim 2 wherein the prostheses have sidewalls with a plurality of openings, the wires being threaded through the openings.
6. The prosthesis delivery catheter of claim 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 of claim 6 wherein the wires can be withdrawn from around the prostheses following deployment thereof.
8. The prosthesis delivery catheter of claim 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 of claim 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 of claim 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 of claim 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 of claim 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 of claim 12 wherein the sleeve is elastomeric.
14. The prosthesis delivery catheter of claim 12 wherein the sleeve is slidable relative to the outer shaft.
15. The prosthesis delivery catheter of claim 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 of claim 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 of claim 16 further comprising a retainer releasably coupled to the longitudinal sections to selectively prevent radial deflection thereof.
18. The prosthesis delivery catheter of claim 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 of claim 15 wherein the sleeve expands by forming a cone shape that flares in the distal direction.
20. The prosthesis delivery catheter of claim 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 of claim 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 of claim 21 wherein the plurality of prostheses are releasably interconnected to each other.
23. The prosthesis delivery catheter of claim 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 of claim 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 of claim 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 of claim 26 wherein expandable member comprises a balloon.
28. The prosthesis delivery catheter of claim 26 wherein the expandable member is configured to expand within a deployed prosthesis in the vessel lumen.
29. The prosthesis delivery catheter of claim 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 of claim 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 of claim 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 of claim 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 of claim 34 wherein the axial displacement is controlled by an expandable sleeve disposed around the desired number of prostheses.
36. The method of claim 35 further comprising retracting the sleeve from around the prostheses after the prostheses have been deployed.
37. The method of claim 34 wherein the axial displacement is controlled by a plurality of wires coupled with the desired number of prostheses.
38. The method of claim 37 further comprising retracting the wires from the prostheses after the prostheses have been deployed.
39. The method of claim 37 wherein the wires are threaded through openings in each of the prostheses.
40. The method of claim 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 of claim 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 of claim 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 of claim 34 wherein the prostheses are releasably interconnected while in the delivery catheter.
44. The method of claim 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 of claim 43 wherein the selected number of prostheses detach from the prostheses remaining in the delivery catheter upon deployment.
Type: Application
Filed: Jun 28, 2004
Publication Date: Dec 29, 2005
Applicant: Xtent, Inc. (Menlo Park, CA)
Inventors: Henry Plain (Atherton, CA), Bernard Andreas (Redwood City, CA), David Snow (Menlo Park, CA)
Application Number: 10/879,949