Abstract
A system for deploying a prosthesis over a Carina between an ipsilateral lumen and a contralateral lumen includes a guidewire, a guidewire capture catheter, a self-expanding tubular prosthesis, and a delivery catheter. The guidewire is first placed in the ipsilateral lumen. The guidewire capture catheter is then advanced from the contralateral lumen to a position at or above the ipsilateral lumen. The guidewire is typically advanced through an occlusion, which may be a total occlusion, and captured by a capture element on the guidewire capture catheter. The guidewire capture catheter pulls the guidewire out through the contralateral side, and the guidewire is used to advance a delivery catheter from the ipsilateral side. The delivery catheter delivers a first segment of the tubular prosthesis in the ipsilateral lumen and a second segment of the prosthesis in the contralateral lumen.
Claims
1. A delivery catheter system comprising: a self-expanding tubular prosthesis having a side opening and configured to be delivered in a linearized arrangement and draped over a delivery body to assume a non-linear configuration over a patient's carina to position the opening at an aorta where the aorta branches into the ipsilateral and contralateral iliac arteries; and a catheter body having a distal end and a proximal end, wherein the self-expanding tubular prosthesis is mounted over the catheter body so that the prosthesis may be positioned over the carina with a distal portion of the catheter body in the contralateral artery and a proximal portion of the catheter body in the ipsilateral artery; and a sheath configured to be disposed coaxially over the catheter body to radially constrain the self-expanding tubular prosthesis in the linearized arrangement so that retraction of the sheath allows the tubular prosthesis to expand with the opening centered at the aorta.
2. A delivery catheter system as in claim 1, wherein the tubular prosthesis comprises a self-expanding metal scaffold.
3. A delivery catheter system as in claim 2, wherein the self-expanding metal scaffold is covered by a graft material.
4. A delivery catheter system as in claim 1, wherein the self-expanding tubular prosthesis has a hinge region in a middle region thereof aligned with the opening.
5. A delivery catheter system as in claim 4, wherein the hinge region comprises a tether.
6. A delivery catheter system as in claim 1, wherein the tubular prosthesis comprises separate, unjoined segments.
7. A delivery catheter system as in claim 1, wherein the sheath includes a distal portion which at least partially covers a distal segment of the tubular prosthesis and a proximal segment which at least partially covers a proximal segment of the tubular prosthesis, wherein the distal portion may be retracted distally to release the distal segment and the proximal portion may be retracted proximally to release the proximal segment.
8. A delivery catheter system as in claim 1, wherein the sheath comprises a single, continuous structure which at least partially covers both distal and proximal segments of the tubular prosthesis so that the entire sheath may be retracted in a single direction to release both segments of the tubular prosthesis.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
(2) FIGS. 1A and 1B illustrate an aortic bifurcation into iliac branch arteries showing partially occlusive disease (FIG. 1A), and totally occlusive disease (FIG. 1B).
(3) FIG. 2 illustrates a prior art method for treating occlusive disease at an aortic bifurcation using “kissing” stents.
(4) FIG. 3 shows an exemplary placement of a folded or bent tubular prosthesis constructed in accordance with the principals of the present invention providing an open area in the lower aorta which is generally free from structure and allows contralateral access of a guidewire and treatment catheter for contralateral access of a guidewire and a treatment catheter for treatment of future disease which may occur at or near the aortic bifurcation.
(5) FIGS. 3A and 3B illustrate a first exemplary tubular prosthesis constructed in accordance with the principals of the present invention having a hinged region between first and second segments thereof.
(6) FIGS. 4A and 4B illustrate a similar hinged tubular prosthesis to that shown in FIGS. 3A and 3B but further having curved or arcing ends of each of the first and second segments which overlap when the tubular prosthesis is in a linearized configuration (FIG. 4A) and which open to provide additional wall coverage of the aorta as shown in FIG. 3.
(7) FIGS. 5A and 5B illustrate a further exemplary embodiment of a tubular prosthesis constructed in accordance with the principals of the present invention having first and second segments joined by a short tether.
(8) FIGS. 6A and 6B illustrate yet a further embodiment of a tubular prosthesis constructed in accordance with the principals of the present invention where the prosthesis includes first and second segments which are unattached.
(9) FIGS. 7A and 7B illustrate yet a further embodiment of a tubular prosthesis constructed in accordance with the principals of the present invention where the prosthesis comprises the tubular body having a hole or fenestration on one side thereof.
(10) FIG. 8 illustrates an exemplary guidewire capture catheter constructed in accordance with the principals of the present invention.
(11) FIGS. 9 and 10 illustrate alternative guidewire capture elements which can be employed on the guidewire capture catheters of the present invention.
(12) FIG. 11 illustrates an exemplary prosthesis delivery catheter constructed in accordance with the principals of the present invention.
(13) FIGS. 12 and 13 illustrate the retraction of a single sheath to release the tubular prosthesis from the catheter of FIG. 11.
(14) FIG. 14 illustrates an alternative sheath structure for the prosthesis delivery catheter of the present invention.
(15) FIGS. 15 and 16 illustrate the retraction in opposite directions of two portions of the sheath to release a prosthesis therefrom.
(16) FIGS. 17-26 illustrate delivery of a tubular prosthesis over a carina in an aortic bifurcation in accordance with the principals of the methods of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
(17) Referring again to FIG. 3, an exemplary tubular prosthesis 10 constructed in accordance with the principals of the present invention will comprise a tubular body having a first segment 12 and a second segment 14. For convenience, as shown here and after, the first segment 12 will be placed in the ipsilateral iliac artery IIA, which is the artery through which the crossing guidewire is to be placed. The second segment 14 will be placed in the contralateral iliac artery CIA which is the iliac artery through which the guidewire capture catheter is to be advanced and the crossing guidewire is eventually to be pulled back by the guidewire capture catheter. The tubular prosthesis, when deployed as shown in FIG. 3, will usually have a connecting region 22 which bendable connects the first segment 12 to the second segment 14 at all times, including when the tubular prosthesis 10 is linearized or straightened for delivery (not shown in FIG. 3) and when the prosthesis is bent and fully deployed with the connecting region 22 draped or tented over the carina C as shown in FIG. 3.
(18) Exemplary embodiments of the tubular prosthesis 10 are shown in FIGS. 3A through 7B. FIGS. 3A and 3B illustrate tubular prosthesis 10A having a first segment 12A connected to a second segment 14A by a hinge region 22A. As shown in FIG. 3B, the hinge region 22A can accommodate bending of the prosthesis and will generally lie over the carina C (FIG. 3) when the stent is deployed. Other features of the tubular prosthesis 10A include a structure comprising and underlying scaffold 16, typically a resilient metal scaffold of the type commonly employed in vascular and non-vascular stents and grafts. Exemplary materials included spring stainless steel and Nitinol®. This scaffold 16 will typically be covered by a graft material which can be any conventional or non-conventional graft material utilized in vascular and non-vascular medical procedures. Exemplary graft materials include expanded PTFE, polyethylenes, and the like. Each of the tubular prostheses 10B-10E described below will usually have a similar structure including an inner scaffold and an outer graft cover.
(19) The inner ends 20A of each of the first and second segments 12A and 14A are shown to be straight and disposed laterally across the prosthesis 10A when the prosthesis is in its linearized configuration. These ends 20A will open into a V-shaped geometry when the stent is folded or bent as shown in FIG. 3B.
(20) The tubular prosthesis 10B of FIGS. 4A and 4B is very similar to that of the prosthesis of FIGS. 3A and 3B. First segment 12B is joined to second segment 14B by a hinge region 22B. The inner edges 20B of the two segments, however, differ in that they are curved inwardly and overlap when the prosthesis 10B is in its linearized or straightened configuration as shown in FIG. 4A. When the prosthesis 10B is opened by bending or folding, as shown in FIG. 4B, the edges 20B of the first and second prosthesis segments open into a smooth and a continuous arcuate profile similar to that shown in FIG. 3. By curving the ends of the prosthesis segments, the effective coverage on the aortic walls can be increased relative to that provided by the straight end segments 20A of prosthesis 10A. It will be appreciated that other end geometries could be employed to both increase and decrease the coverage of the aortic wall by inclining, curving, or otherwise modifying the shape of the interior ends of the first and second prosthesis segments. Other geometries include castellated ends, zig-zag ends, serpentine ends, and the like.
(21) Referring now to FIGS. 5A and 5B, a tubular prosthesis 10C includes a first segment 12C and a second segment 14C joined together by a tether region 22C. The tether 22C can be formed as a part of the underlying scaffold (not shown) or could be later joined to previously manufactured scaffold segments. The tether can bend at its middle, as shown in FIG. 5B, which case the segments 12C and 14C would be generally symmetrically placed in the ipsilateral and contralateral iliac arteries. Using a tether 22C, however, allows the bend point to be shifted which in turn allows a symmetric positioning of the first and second segments in the ipsilateral and contralateral iliacs or other lumens, respectively. The ability to provide such repositioning allows improved treatment of asymmetric diseases in the affricated lumens. The ability to move the edges 20C away from the Carina also allows a user to minimize coverage of the aortic wall should that be desired. Referring now to FIGS. 6A and 6B, in some instances it may be desirable to have no connecting region between a first prosthesis segment 12D and a second prostheses segment 14D. In those instances, the segments may be oriented to accommodate the bifurcation, as shown in FIG. 6B, using the delivery systems of the present invention. Generally, however, it will be preferred to use segments which are joined together by a hinge region, tether, or other coupling structure. In other instances, the first and second segments may be deployed in an unconnected manner and it will be possible to subsequently introduce a connecting region to help pull the relative positions of the segments.
(22) Referring now to FIGS. 7A and 7B, a tubular prosthesis 10E comprises a generally continuous tubular structure 24 having a first segment 26 and a second segment 28. The first and second segments are defined by the presence of an opening or fenestration 30 which will be sized to open to a diameter (as shown in FIG. 7B) which corresponds at least generally to the aortic diameter immediately above the Carina. The scaffold structure of the prosthesis 10E will allow the opening 30 to expand and the closed portion of the tubular body 24 to bend into an arc 32, as shown in FIG. 7B. The tubular prosthesis 10E may be delivered by the delivery systems, as described hereinafter, that will generally not be preferred over the hinged, tethered, or similarly coupled structures described previously.
(23) Referring now to FIG. 8, an exemplary guidewire capture catheter 40 comprises a catheter body 42 having an inner tubular member 44 and an outer tubular member 46. The inner and outer tubular members are arranged coaxially and can axially slide relative to each other in order to deploy an expandable guidewire capture element 48, as described in more detail below. The expandable guidewire capture element is disposed generally at a distal end 50 of the catheter body and a deployment handle assembly 52 is disposed at a proximal end 54 of the catheter body. Usually, an atraumatic tip 56 extends beyond the distal end of the expandable guidewire capture element 48 in order to minimize trauma which could occur if the somewhat rigid capture element were at the tip of the catheter 50. The guidewire capture catheter will be configured to be advanced over a Guidewire followed by reference letters GW, with the guidewire generally passing through an interluminar passage of the inner tubular member 44 and not shown). The guidewire capture element 48 is shown in its low profile or radially collapsed configuration in solid line in FIG. 8. The capture element 48 may be radially expanded into the configuration shown in broken line in FIG. 8 by pushing pusher 48 of the handle assembly relative to a grip 60 at the end of the outer tubular member 46. Pushing the pusher advances the distal end of the inner tubular member 44 which is connected to a proximal end of the expandable guidewire capture element 48. As the distal end 64 of the capture element is attached to the inner tubular member, the capture element is axially foreshortened which forces the radial expansion.
(24) As illustrated in FIG. 8, the expandable guidewire capture element 48 comprises a plurality of axial elements circumferentially distributed over the catheter body 42. Each linear element has weakened regions which preferentially bend when the capture element is actually foreshortened. As illustrated, each individual element 66 has a pair of weakened regions which result in a generally U-shaped expanded structure. As described hereinafter with respect to the method, such an expanded cage structure will both place radially expansive forces against the aortic or other lumenal wall in which they are extended. Such expansion force will assist in guidewire exit when the guidewire is being advanced subintimally. Additionally, after the guidewire exits and passes through the expanded guidewire capture element, the capture element may be collapsed to capture the guidewire and allow the guidewire to be drawn out through the contralateral lumen as the capture catheter is withdrawn.
(25) Referring to FIGS. 9 and 10, the expandable guidewire capture element may have a variety of specific implementations. As shown in FIG. 9, instead of discreet axial elements which fold upon foreshortening, an alternative capture element 48A may comprise a polymeric braided structure which will regularly expand into a generally disk geometry (shown in broken line) when the inner tube 44 and outer tube 46 are closed together.
(26) A further exemplary alternative as shown in FIG. 10 where an expandable guidewire capture element 48B comprises a balloon 68 optimally covered by a lattice structure 70 which can expand with the balloon. The balloon and lattice are show in their full expanded configurations in full line and their expanded configurations in broken line. The presence of the lattice 70, which can generally have a stent-like pattern or restructure, can provide a more positive transmission of force to the aortic or other wall in which the capture element is being expanded. Additionally, the lattice can help capture a guidewire which is advanced to the capture element
(27) Referring now to FIGS. 11-13, a first exemplary delivery catheter constructed in accordance with the principles of the present invention will be described. The delivery catheters are intended to deliver the tubular prosthesis described previously into and over a Carina in order to stent or graft regions of the branching vessels on either side of the Carina. The first delivery catheter embodiment 80 comprises a catheter body 82 having a distal end 84 and a proximal end 86. A handle or hub 88 is disposed at the proximal end 86 of the catheter body and a guidewire port 90 is provided at the distal end 84. Catheter 80 will be configured for advancement over the crossing guidewire which has been placed from the ipsilateral lumen to the contralateral lumen over the Carina as will be described below.
(28) The retractable sheath 92 is coaxially mounted over the catheter body 82 and has a sheath handle 94 which allows the retraction of the sheath relative to the catheter body. The tubular prosthesis 12 (FIGS. 12 and 13) is initially maintained beneath a distal end or portion of the retractable sheath 92 where it remains as the catheter is being advanced over the guidewire to the region over the Carina. The sheath 92 may be then be proximally retracted, as shown in FIG. 12, so that the first segment 12 of the tubular prosthesis is released and begins to self-expand at the desired location. Continued retraction of the sheath 92, as show in FIG. 13, results in full release of the prosthesis 10, including both the first segment 12 and the second segment 14, as shown in FIG. 13. Complete deployment of the tubular prosthesis will, of course, occur when the catheter body 82 is retracted from within the interior of the prosthesis. Additionally, of course, the guidewire will also be fully retracted but the guidewire will generally not inhibit the prosthesis from fully bending and folding within the target anatomy.
(29) Referring now to FIGS. 14-16, a second exemplary embodiment of the delivery catheter 100 constructed in accordance with the principles of the present invention will be described. The delivery catheter 100 includes a catheter body 102 which is preferably divided into an ipsilateral portion 102A and a contralateral portion 102B. The delivery catheter will further comprise a sheath 104 which is also divided into an ipsilateral portion 104A and a contralateral portion 104B. The tubular prosthesis 10 was initially constrained by the sheath assembly with a full width ipsilateral portion 104A covering the first segment probe of the stent and the contralateral portion 104B covering the second segment 14 of the prosthesis. Other than that shown in FIGS. 14-16, it will be appreciated that the sheath portions 104A and 104B will meet at a point which is generally in the middle of the catheter 100 and catheter body 102 so that the catheter may be deployed completely from the entry sheath in the ipsilateral lumen to the exit sheath and the contralateral lumen. Each sheath will be accessible external to the patient so that the sheaths may be retracted to deploy the tubular prosthesis 10, generally as shown in FIG. 15 and FIG. 16.
(30) The tubular prosthesis 10 will usually include radiopaque markers 106 near its middle and in each end to facilitate positioning of the stent at the desired location over the carina C of the bifurcated lumens. Alternatively or additionally, the depict markers could be provided on the sheath and/or the catheter body.
(31) Retracting the ipsilateral sheath portion 104A toward the ipsilateral vasculature and retracting the contralateral sheath portion 104B toward the contralateral vasculature will result in a symmetric release of the tubular prostheses as shown in FIGS. 15 and 16.
(32) While it would be possible to deliver the sheath in this way using a continuous catheter body 102 which would remain within the tubular prosthesis 10, such deployment would require that the catheter body be separately withdrawn from within the tubular prosthesis in order to allow the prosthesis to fully deploy. Thus, in many embodiments, it will be preferred to provide the catheter body 102 as a separate ipsilateral portion 102A and contralateral portion 102B. In this way, the separate portions of the catheter body 102 may also be separately retracted in ipsilateral and contralateral directions from within the tubular prosthesis in order to permit full deployment of the tubular prosthesis, as shown in FIG. 16B. In such embodiments, ipsilateral components of the delivery catheter 100 will eventually be withdrawn through the ipsilateral access sheath or contralateral portions of the delivery catheter will be withdrawn through the contralateral access sheath.
(33) Referring now to FIGS. 17-26, delivery of the tubular prosthesis 10 of the present invention in accordance with an exemplary method of the present invention will be described. Initially, as shown in FIG. 17, a crossing guidewire 110 is placed into the ipsilateral iliac artery IIA through an access sheath 114. The crossing guidewire is advanced until it reaches a downstream side of a chronic total occlusion. A second, contralateral guidewire 112 is advanced into the contralateral iliac artery CIA through an access sheath 116 and advanced typically until it reaches the aorta A.
(34) As shown in FIG. 18, the guidewire capture catheter 40 is then advanced through the access sheath 116 over the contralateral guidewire 112 to position the expandable guidewire capture element 48 in the aorta in a region above the Carina and near the upstream side of the Chronic total Occlusion.
(35) As shown on FIG. 19, the expandable guidewire capture element has been radially expanded so that it engages the aortic wall circumferentially along the line generally aligned with the upstream side of the chronic total occlusion. The expanded guidewire capture element implies an expansive force against the aortic wall, and in particular provides tension and a backstop along the upstream side of the chronic total occlusion CTO.
(36) After deployment of the expandable guidewire capture element 40, the crossing guidewire 110 may be advanced past the chronic total occlusion CTO as shown in FIG. 20. Typically, the crossing guidewire 110 will follow a sub intimal path SIP, where the engagement of the capture element 48 facilitates reentry of the crossing guidewire 110 into the aortic lumen, as illustrated. Not only does the expanded guidewire capture element 48 facilitate reentry of the crossing guidewire, the element can also capture a distal end of the guidewire, as will be described with reference to FIG. 21.
(37) As shown in FIG. 21, the expandable guidewire capture element 48 may be collapsed over the guidewire to firmly engage the guidewire so that the catheter may be used to pull the guidewire over the carina C. By completely withdrawing the guidewire capture catheter 40 from the contralateral iliac aorta and through the access sheath 116, as shown in FIG. 22, the crossing guidewire 110 will be deployed to cross the carina C with one end accessible through the ipsilateral access sheath 114 and the other end accessible through the contralateral access sheath 116. Optionally, the contralateral guidewire 112 may be left in place to establish further access if needed. For convenience, the contralateral guidewire 112 will not be shown in the remainder of the figures.
(38) As show in FIG. 23, optionally a pre-shaped guide catheter 120 may be advanced through the ipsilateral access sheath over the guidewire to define a path through or past the chronic total occlusion CTO.
(39) Either with or without the guide catheter, a prosthesis delivery catheter may then be introduced using the previously placed crossing guidewire 110. As shown in FIG. 24, the delivery catheter 100 which has a pair of sheath portions 104A and 104B is used for this example. After positioning the delivery catheter 100 over the carina C, the ipsilateral sheath portion will be accessible through the ipsilateral access sheath 112 and the contralateral sheath portion 104B will be available through the contralateral access port 116. The access sheaths may then be withdrawn in ipsilateral and contralateral directions, respectively, allowing the tubular prosthesis segments 12 and 14 to radially expand in situ, as shown in FIG. 25. As shown in FIG. 25, the catheter body 102 of the delivery catheter is a single element and will remain in place after the tubular prosthesis has radially expanded.
(40) The catheter body 102 may be withdrawn through either of the access sheaths 112 or 116, the crossing guidewire in place. The crossing guidewire can also be withdrawn, leaving the fully deployed prosthesis 110 in place with the first segment 112 in the Ipsilateral Iliac Artery in the second segment 14 present in the Contralateral Iliac Artery. The stent deploys with the hinge region 22 over the carina C.
(41) While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
