WO2007011510A2

WO2007011510A2 - Endograft deployment system

Info

Publication number: WO2007011510A2
Application number: PCT/US2006/025271
Authority: WO
Inventors: Darwin Eton
Original assignee: The University Of Miami
Priority date: 2005-07-15
Filing date: 2006-06-28
Publication date: 2007-01-25
Also published as: WO2007011510A3

Abstract

An endograft hanger for expanding and suspending an endograft in the circulation for properly placing the endograft with respect to a target segment of a blood vessel includes a main body and a plurality of expandable limbs adapted to be operatively coupled to an endograft. Once the endograft is suspended in a desired location, stents are deployed to secure the endograft in position. A method for deploying an endograft is also provided, whereby the endograft that is free from stent structures is disposed in a reduced diameter configuration and, attached to a graft hanger is conducted to a target region of a blood vessel. Once in place, the graft is released from an introducer sheath and the graft hanger is released so that the hanger limbs expand to re-expand the endograft in a target region of the blood vessel.

Description

ENDOGRAFT DEPLOYMENT SYSTEM

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Provisional Application No. 60/699,364, filed July 15, 2005, the entire content of which is hereby incorporated by reference in this application.

BACKGROUND OF THE INVENTION

Conventional endografts are tubes of graft material lined with metal stents. For storage and delivery, the endografts are crimped down and held in a sheath with the metal stent pressing against the graft material within the sheath. Consequently, the assemblies have a relatively short shelf life.

Dual layer endografts have been proposed, for example in my co- pending Application No. 10/680,350, filed October 8, 2003, the entire disclosure of which is incorporated herein by reference. A problem associated with such a multi-layer endografts, however, is that using conventional delivery techniques, a larger deployment system will be required. Another consideration with endografts is that the grafts must be deployed exactly on target. During deployment the force of blood flow as a consequence of the beating heart can push the graft out of the planned geometry. If the graft slips even a little, it could slip into the aneurysm or it could cover branches that one does not intend to cover.

BRIEF DESCRIPTION OF THE INVENTION

The invention addresses the above-noted deficiencies of conventional endograft deployment by uncoupling the graft from the stent(s) and providing a graft delivery system that allows the graft to be pushed and pulled to a target delivery site in advance of stent deployment. By decoupling the graft and stent for deployment, a lot of the volume of the deployment system is eliminated, so that a smaller delivery system can be used with smaller access. Moreover, the stent can be placed exactly where needed so that the entire graft does not need to be stent lined and there is the additional opportunity to use different types of stents for different locations depending upon the circumstances of the implantation. Also, the shelf life of the device is increased because there is no stent on graft compression trauma.

Yet another advantage of separately deploying the graft using the system of the invention is that if there is a problem, the graft can be retrieved through the deployment sheath and pulled out since there are no metal stents within it. Additionally, graft placement according to an embodiment of the invention allows the graft to be hung in the circulation so that it may be sutured in place, e.g., using systems and methods of the type disclosed by Dr. Parodi in USP 6,336,933; 6,592,593; 6,800,081 ; and U.S. Published Application No. US/2005/0015100, the disclosures of which are incorporated herein by this reference.

Another advantage of hanging the endograft in the circulation before deploying the stents is the limitation of the "windsock" effect. This effect is most prominent in the descending aorta. In this location the impulse from the heart is so strong that a deploying endograft can be pushed downstream as it is opening up and before it has a chance to successfully anchor into the aortic wall. The present invention deals with this problem.

While the proposed approach has the advantages of reducing the size of the deployment system and increasing shelf life of the graft, a consequence is that an additional, axillary access point is required to implement the novel deployment method. It should be noted, however, that providing an additional, axillary axis point is no more problematic than the one or two femoral access points required for conventional endograft and bilateral endograft placement, and the benefit is that now the graft can be more precisely placed and with greater versatility before stent placement. BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of this invention, will be more completely understood and appreciated by careful study of the following more detailed description of the presently preferred exemplary embodiments of the invention taken in conjunction with the accompanying drawings, in which:

FIGURE 1 schematically illustrates guidewire feed for upper and lower access in an example embodiment of the invention;

FIGURE 2 schematically illustrates the femoral artery sheath deployed into the aorta and the femoral and axillary magnetic guidewires aligned for connection;

FIGURE 3 schematically illustrates axillary guide catheter advancement over the axillary-femoral monorail;

FIGURE 4 illustrates the feed of a femoral guidewire through the axillary guide catheter to the axillary access;

FIGURE 4A is a schematic, exploded perspective view, partly cut-away to illustrate detail, of a multi-lumen guide catheter which may be used in an example embodiment of the invention;

FIGURE 5 is a schematic perspective view of a graft for placement using a graft deployment system embodying the invention;

FIGURE 6 is a schematic illustration of a bifurcated graft for deployment using a deployment system embodying the invention;

FIGURE 7 is a schematic illustration of a graft disposed in a storage and deployment sheath;

FIGURE 8 is an exploded-schematic perspective view of a graft hanger in an example embodiment of the invention; FIGURE 9 is a schematic perspective view illustrating a graft hanger in an embodiment of the invention with suture filaments secured thereto;

FIGURE 10 is a schematic perspective view of a graft hanger being displaced through an axial guide catheter for attachment to a graft in an example embodiment of the invention;

FIGURE 11 schematically illustrates a graft hanger disposed for attachment to a graft in an embodiment of the invention;

FIGURE 12 illustrates a graft hanger secured by sutures to a graft in an embodiment of the invention;

FIGURE 13 schematically illustrates release of a graft from the femoral sheath in an example embodiment of the invention;

FIGURE 14 schematically illustrates a graft in its deployed position with the aortic structure omitted for clarity;

FIGURE 15 schematically illustrates a fully expanded graft in an example embodiment of the invention;

FIGURE 16 is a schematic illustration of deployment of a graft for placement within a thoracic aneurysm;

FIGURE 17 is a view similar to FIGURE 16 showing a graft fully released from the femoral sheath;

FIGURE 18 is a schematic illustration of a fully expanded graft disposed to bridge a thoracic aneurysm in an example embodiment of the invention;

FIGURE 19 is a schematic illustration of guidewire coupling for bifurcated graft placement in an example embodiment of the invention; FIGURE 20 schematically illustrates the attachment of the contralateral guidewire to the contra-lateral sutures of a bifurcated graft;

FIGURE 21 schematically illustrates the contra-lateral suture being drawn into the contra-lateral iliac artery;

FIGURE 22 illustrating the contra-lateral limb suture drawn through a contra-lateral femoral sheath;

FIGURE 23 illustrates an extended contra-lateral femoral sheath in an alternate embodiment;

FIGURE 24 illustrates the graft deployed but upstream of its final position, with central guidewire(s) omitted for clarity;

FIGURE 25 illustrates the bifurcated graft in its final position, with central guidewire(s) omitted for clarity;

FIGURE 26 schematically illustrates guidewire capture according to a further alternate embodiment of the invention;

FIGURE 27 illustrates femoral guidewires coupled to monorails and a bottom marionette sutures for graft placement;

FIGURE 28 schematically illustrates the graft received over a bifurcated graft hanger according to a alternate embodiment of the invention; and

FIGURE 29 schematically illustrates a storage and deployment sheath receiving a bifurcated hanger and bifurcated graft for attachment to threaded monorails. DETAILED DESCRIPTION OF THE INVENTION

As a first step in the deployment process, guidewire access is required through either axillary artery and from either femoral artery for a tube graft, or through both femoral arteries for bifurcated graft placement, as described in greater detail below. To enter the vascular system, the conventional

Seldinger technique is used. For upper access, the surgeon has two choices for guidewire placement: the guidewire can be fed through the right subclavian or the left sub-clavian artery, with the respective sub-clavian artery being entered from the brachial artery in the respective arm. In regard to the lower access, if a tube graft is to be used then only a single lower access is required. For purposes of this disclosure, the left femoral artery serves as the lower access, although it is to be understood that the right femoral artery may be accessed instead, and both lower access points will be used for bifurcated graft placement.

FIGURE 1 schematically illustrates guidewire feed for upper and lower access. As noted, upper access can be either through the right or left brachial artery. For purposes of illustration, the axillary guide wire 10 is shown disposed through a sheath from the left arm 12, through the aortic arch 14 and into the descending aorta 16. Access through the left femoral artery is also schematically depicted in FIGURE 1.

As schematically shown in FIGURES 1 and 2, a femoral artery sheath 20 is placed through the femoral artery and advanced into the aorta. The purpose of the femoral sheath 20 is to protect the femoral and iliac arteries from trauma during graft deployment. The femoral artery sheath is placed to a level 1 to 2 cm above the planned deployment of the proximal aspect of the graft. As described in greater detail below, in due course an axillary guide catheter 22 (FIG. 3) is fed from the axillary access point. Since the latter will need to pass through the femoral artery sheath 20, the femoral artery sheath 20 is larger than the axillary graft catheter 22. As suggested above, the femoral artery sheath 20 is placed using the standard Seldinger technique. FIGURE 2 illustrates the femoral artery sheath deployed into the aorta 16 with the trocar removed and a guidewire 24 in place. In this regard, as presently proposed, the sheaths are placed with standard guidewires. The guidewires are then removed and guidewires 24 and 10 are placed.

The guidewire 10 fed from the axillary access point and the guidewire 24 fed from the femoral access point are coupled in the aorta 16. In an example embodiment of the invention, this coupling is achieved by using magnetically tipped guidewires, for example, of the type disclosed in U.S. Patent No. 5,624,430, the disclosure of which is incorporated herein by this reference. It is to be understood, however that magnet-tipped guidewires are only one example of a manner in which respective axillary and femoral guidewires may be coupled. Indeed, as an alternative, the guidewires may be threadedly coupled, or coupled with by engaged hooks, snares, or any other manner of mechanically coupling the respective end portions of the guidewires so that the tips will thereafter be held together for respective pushing and pulling of the wires out through one of the access points. In an example embodiment, the coupled guidewires are pulled all the way through so that a single monorail wire 10 is disposed to extend from the groin to the arm and the surgeon has access from both ends of the existing monorail so that the surgeon can now carry out the further steps of the deployment technique from either access point. In the illustrated example embodiment of the invention, the femorally placed guidewire 24 (FIG. 2) is used to pull the axillary guidewire 10 out through the femoral introducer sheath 20.

As illustrated in FIGURE 3, the axillary guide catheter 22 is next advanced over the monorail into and through the femoral artery sheath 20. It is to be noted that, as schematically illustrated in FIGURE 1 , an axillary sheath similar to the femoral sheath 20 is provided to protect the respective arteries from the structures shuttled back and forth in the circulation as it is desirable to minimize rubbing against the artery luminal surfaces themselves. Thus, the axillary guide catheter is desirably fed through an axillary sheath that is disposed through the axillary artery much like the femoral sheath is disposed through the femoral artery to protect the same from the passage of catheters and components. Once the axillary guide catheter is advanced out through the femoral sheath, the monorail 10 is removed. Thereafter, as illustrated in FIGURE 4, a femoral guidewire 26 having a distal most tip 28 adapted for attachment to a graft hanger 30 (described in greater detail below) is fed all the way through the axillary guide catheter 22 back up into the arm and out through the brachial access site. It is to be understood that as an alternative, an axillary guidewire 10 can be provided having a magnetic or other coupling at a first end thereof for coupling to the complementarily tipped femoral guidewire 24 and having an opposite end configured for coupling to the graft hanger. Therefore, the structure described as the femoral guidewire 26 may be an axillary guidewire/monorail 10 having a suitably configured upper end.

FIGURE 5 depicts a tubular graft 32 with metal stent omitted. A Dacron graft is provided by way of example which will be disposed in a reduced diameter configuration for deployment, such as by providing a series of pleats (FIGURE 7). The pleated, reduced diameter graft is maintained in its constricted configuration by being disposed in a storage and deployment sheath 34, as schematically shown in FIGURE 7. The sheath is provided with a beveled top 36 to facilitate passage thereof into an access sheath or catheter as described in greater detail below.

An example graft hanger 30 is illustrated in FIGURE 8. The graft hanger includes a main body 38 and a plurality of hanger limbs 40 resiliently mounted to the main body 38 so as to project away from the longitudinal axis of the hanger main body in the absence of any force applied thereto and so as to be disposed approximately parallel to the longitudinal axis of the hanger body when a constricting force is applied thereto (FIGURE 10). In the illustrated example embodiment, there are four hanger limbs 40 provided. It is to be understood, however, that two, three, or more than four hanger limbs may be provided.

In an example embodiment, the hanger limbs 40 are symmetrically 5 disposed about the circumference of the hanger main body 38 so as to provide uniformly distributed attachment points for the graft 32. The distal end of each hanger limb includes a loop hole 42 or other suitable structure for attachment of a suture thread or other filament 44 thereto. The main body 38 of the graft hanger 30 is configured to be selectively coupled to a guidewire. 0 In the illustrated embodiment, the graft hanger 30 is configured to be selectively coupled to a guidewire at each longitudinal end thereof. Thus, in an example embodiment, a threaded bore 46 (FIG. 8) is defined, e.g., in each longitudinal end of the graft hanger main body 38 so it is possible to threadedly attach a guidewire 26,48 to extend in each direction from the graft 5 hanger 30. In an example embodiment, the main body is threaded so that a 0.035 inch (0.9 mm) guidewire can be screwed to both ends thereof.

The hanger body diameter is limited by the sheath 22 that it is fed through (as described more particularly below). By way of example, the sheath 22 external diameter is preferably less than about 12F to be placed o percutaneously, so the sheath internal diameter would then be about 10F. The hanger body 38 should fit loosely within the sheath, so it is desirably on the order of 8-9F, or maximally about 3 mm in diameter, more typically 2-3 mm in diameter.

The hanger limb length as presently proposed is long enough so that 5 when the limbs spring open (as described more fully below) they reach the aorta wall at an acute angle. The largest diameter of the normal aorta is typically less than 3 cm, so the hanger limb may advantageously be on the order of about 3-5 cm in length where the graft assembly comes from the femoral level, or longer, e.g. the length of the graft (about 15 cm), when the graft assembly comes from the axillary level. It is to be understood that the above described dimensions are provided solely by way of information and example and, therefore, the invention is not to be limited to

As mentioned above, the guidewire 26 extending from the groin to the axila is engaged with the first longitudinal end 50 of the main body 38 of the graft hanger 30 and the other, axillary guidewire 48 is attached to the opposite end of the hanger, by screw threading in an example embodiment. FIGURE 9 shows the respective femoral and axillary guidewires attached to the hanger main body, as by threading, and illustrates sutures 44 attached to each of the hanger limbs 40. In one example embodiment, described hereinbelow, the graft 32 is attached adjacent the femoral access. In another example embodiment, the graft can be attached at the axillary end.

Referring now more particularly to the illustrated example embodiment, once the guidewires 26,48 are secured to the graft hanger main body 38, and the sutures are attached at the axillary access end as illustrated in FIGURE 8, the hanger limbs 40 are compressed and the hanger 30 is inserted into the axillary guide catheter 22. The femoral guidewire 26 is then used to pull the compressed hanger, with sutures 44 trailing through the axillary guide catheter 22, to and out at the femoral access, as schematically illustrated in FIGURES 10 and 11. With the hanger limbs 40 protruding from the axillary guide catheter 22, each suture 44 is removed from the respective hanger limb and attached to respective attachment points about the circumference of the distal end of the graft 32, as shown in FIGURE 12. In an example embodiment, very small radio-opaque metal eyelets 52 may be defined at spaced locations about the circumference of the graft material, as shown in FIGURES 5, 11 and 12, to serve as attachment points for the "marionette" sutures 44. In an example embodiment, at the bottom of the graft 32 in an example embodiment, a bottom eyelet 54 and respective marionette suture 56 is provided so that once the graft is disposed into the circulation, it can be ensured that the graft is seated correctly. Thus, referring to FIGURE 5, in an example embodiment five radio- opaque markers or eyelets may be provided through which marionette sutures are threaded, four (at 52) in the top of the tube graft, one each to correspond to the hanger springs 44, with more or fewer provided consistent with the number of hanger limbs 40, and one (at 54) adjacent the bottom edge in the case of a tube graft. Referring to FIGURE 6 and as described in greater detail below, a bottom radio-opaque eyelet 58 for receiving a marionette suture is provided in each of the legs 60 of a bifurcated graft 62. Once the tube graft top end is in place, the marionette suture of the bottom of the graft may simply be pulled to properly orient the bottom part. Additional marionette sutures associated with the bottom of the graft may of course be provided if deemed necessary or desirable. In the alternative, the sutures may be attached directly to the graft material.

As an alternative to using a conventional single lumen catheter as the guide catheter 22, a multi-lumen guide catheter 122 can be provided, as schematically illustrated in FIGURE 4A, having a central lumen 18 for selectively receiving a guide wire 10, 26 and/or guide wire/graft hanger assembly, and peripheral lumens 118 for each marionette suture 44. The catheter is shown broken-away part way along its length to reveal the lumen configuration along the length. With such a catheter, each of the, e.g., four, marionette sutures 44 is pre-threaded down a respective peripheral lumen 118, along the entire length of the catheter to its tip, for example as an off-the- shelf product. The pre-threaded catheter would then be passed, as the guide catheter described above, from the axilla to the groin. The graft hanger 30, in this case without sutures, would then be passed down the central lumen. Each suture would then be pulled as needed to extend from the tip of the catheter and looped into a respective eyelet at the top of the graft and attached to the hanger. This assembly would avoid any concerns regarding remote identification and/or tangling of the marionette sutures 44. As illustrated in FIGURE 4A, optionally the catheter has an end bullet cap 123 mounted to the distal end thereof to provided a smooth transition at the tip of the catheter. In the illustrated example, the guidewire extends through the cap 123, but the sutures 44 are attached to the cap, to be extended from the catheter when the cap is removed.

Next the graft hanger 30 is pulled back into the axillary guide catheter

22 and the axillary guide catheter containing the graft hanger is pulled up the femoral artery sheath towards the circulation. At the same time, the sheath 34 containing the reduced diameter graft 32 is inserted into the femoral artery sheath valve 64 and the graft is pulled through it up into the femoral sheath 20. If deemed necessary or desirable, the rear cap 66 of the storage sheath 34, which is provided to minimize blood loss, can be removed and the graft 32 pushed out of the sheath 34. Once the graft 32 is in the femoral sheath 20, the sheath 34 is withdrawn from the valve 64. The entire hanger 30 and graft 32 assembly is thereafter pulled by displacing the axillary catheter 22 containing the hanger, through the femoral sheath and pulling along the graft structure 32 with the axillary guidewire 48. If friction makes advancement difficult, the sheath 34 can be reintroduced into the femoral sheath valve and a coaxial plastic flexible rod inserted into the femoral sheath over the femoral guidewire, to push the graft. Otherwise, the valve 64 of the respective introducer sheath 20 allows the femoral and axillary guide wires 26,48 and the sutures 44,56 adjacent thereto to be exteriorized without arterial bleeding.

It is to be understood that there are alternatives for attaching the hanger to the graft, and for conducting it to the deployment site. While it has been described to attach the sutures 44 and the hanger 30 to the graft 32 adjacent the femoral access point, it is to be understood that instead, input of the reduced diameter graft 32 and feed of the graft hanger and graft assembly can be adjacent and from the axillary access. Those skilled in the art will understand the variety of options for assembly and deployment of the graft hanger and graft based on the above-description. It is further to be understood that the graft hanger 30, marionette sutures 44, 56, and graft 32 can be assembled in advance for rapid attachment to the respective guidewires 26, 48 and deployment as may be deemed necessary or desirable, for reducing the cost of manufacture and time for deployment. As previously mentioned, the graft 32 is stored in a sheath 34 following pleating or other compaction to reduce its diameter. Thus, consistent with the pre-assembly alternative, and as an alternative to disposing solely the collapsed graft 32 in the graft storage sheath 34, the graft hanger 30 and top marionette sutures 44 may be earlier attached to the top of the graft 32 and the graft hanger 30, marionette sutures 44,56 and graft all stored within the storage and deployment sheath 34. It is also to be appreciated that where the marionette sutures 44,56, graft hanger 30 and graft 32 are all stored together in the storage sheath 34, deployment of these components may be initially from the axillary access point in which case the beveled edge 32 of the storage deployment tube is adjacent the bottom of the graft and the cap 66, provided for the purpose of minimizing arterial bleeding, is provided adjacent the top of the graft hanger with the marionette sutures and axillary guide wire passing therethrough. In this case, the suture filament 56 attached to the bottom of the graft 32 may be used to facilitate movement of the graft through the axillary guide catheter 22, while the graft hanger 30 is moved by displacement of the femoral and axillary guide wires 26,48.

Once the graft has been advanced to the target delivery site, which may be monitored radiographically particularly where eyelets 52,58 are provided for suture attachment and in any event by monitoring the locus of the hanger structure, the femoral introducer sheath 20 may be drawn back down exposing the body of the graft as schematically illustrated in FIGURE 13.

Once the graft is in position, the graft hanger is moved down to near the top of the graft to open it, e.g., by holding the sutures 44 and shifting the hanger 30. Each of the limbs 40 of the hanger 30 acts as a spring to spring open when pulled or pushed out of the axillary guide catheter 22, thereby helping to open the graft 32. When the secured end of the graft is opened a little bit, blood flowing through the circulation flows in and the hydrostatic force of the blood will actually facilitate expansion of the graft.

Referring to FIGURES 14 and 15, one end of each of the sutures 44 extends through the respective eyelet 52 of the graft 32 and attached to the respective hanger limb. The other ends of the suture lines 44 extend through the axillary guide catheter 22 to and out the axial access, where they are available to the surgeon. Thus, as the hanger, is pushed or pulled down the axillary guide catheter 22 to a level just above the graft, any slack in the sutures resulting from the movement of the hanger is taken up at the axillary access point, as mentioned above. As the hanger 30 exits the guide catheter 22 the hanger limbs spring open, in turn opening up the graft. Once the graft has been pushed or pulled out of the femoral introducer sheath as in FIGURE 14, the graft is hanging from the "marionette" sutures 44. The individual marionette sutures may be pulled to finalize the proximal neck anchoring position and the bottom suture 56 can likewise be pulled to displace the graft downwardly. Thus, the surgeon can pull on one or another or all of the sutures as necessary or desirable to position the graft exactly where desired. There are a variety of options to facilitate manipulation of the hanger limbs. For example, the sutures may be color coded and the respective hanger limbs may be radiographically identified to coordinate with the respective color suture. The ability to manipulate the hanger and/or hanger limbs gives the surgeon the ability to precisely position not only the graft but also keep it anchored by the action of the spring-loaded hanger limbs until a stent can be separately delivered, to anchor the graft to the vessel wall.

The stent(s) (not shown) for permanent anchoring of the graft may then be advanced via a suitable deployment system over the femoral guidewire 26 into the graft 32 and deployed. In the alternative, the graft can be sutured in place as taught, e.g., by Parodi. Because the stent(s) is/are delivered after the graft 32 has been put into position, the surgeon or cardiologist can identify and place an appropriate stent as needed for the particular patient and the particular deployment site. For example, the surgeon may select a mechanically expandable stent or a self expanding stent or a stent of a particular length or configuration as determined by the particular patient physiology and the final deployment location of the stent. In this manner, the endograft is effectively assembled in vivo by the delivery of selected stents to the placed graft. This allows the surgeon to address the particular patient's requirements so that the endograft is not simply a piece of one-size-fits-all plumbing.

To remove the deployment system, the extra suture length is cut away so that the entire suture length does not need to be dragged all the way through the guide catheter and the axillary guide wire 48 is pulled until the hanger 30 is removed with the attached marionette sutures 44 from the circulation. The axillary guide catheter 22 may be left in position for a completion angiogram or simply withdrawn together with the hanger and marionette sutures.

To remove the bottom marionette suture 56, one end of the marionette suture is cut flush with the valve 64 and the other end is pulled so that it threads out of the graft and out of the femoral sheath 20.

FIGURE 16 schematically illustrates a thoracic aneurysm 70 as an example of where the deployment device of the invention may be advantageously used to properly place a thoracic endograft 72 of desired size. As noted above, each limb of the hanger 30 may be identified so as to be independently identifiable on the fluoroscope. In this regard, the hangers may have a differing shape or may be differentiated by additional markers. In the illustration of FIGURE 16, the graft 72 is being deployed and the femoral sheath 74 is being withdrawn to allow the graft to preliminarily expand. FIGURE 17 shows the graft 72 fully revealed to traverse the thoracic aneurysm 70. The hanger 30 is then disposed to project from the guide catheter 76 and, as shown in FIGURE 18, full expansion of the hanger limbs 40 facilitates full expansion of the graft material, after which the selected stents may be deployed.

As mentioned hereinabove, a modified technique embodying the invention may be provided when a bifurcated graft is placed. An example bifurcated graft 62 was illustrated in FIGURE 6 and briefly described above with reference thereto. In this regard, with a bifurcated graft, the graft must be correctly seated with each leg 60 of the graft extending into the respective common iliac artery. Providing marionette sutures 78,79 associated with each of the legs of the bifurcated graft provides a way of pulling the graft down into each iliac artery after which a suitable stent or stents may be deployed to anchor the graft 62.

To place a bifurcated graft 62, a femoral-femoral crossover monorail is provided where by the marionette sutures associated with one of the legs of the bifurcated graft can be fed to and through the respective iliac artery in advance of hanger deployment. In an example embodiment, as illustrated in FIGURE 19, a truncated introducer sheath 80 is disposed in the right femoral artery and an elongated femoral sheath 20, also used to place the graft, is provided in the left femoral artery. A guidewire 82,24 is fed through each femoral sheath to be joined in the aorta. In this example embodiment, magnetically tipped guidewires are provided to enable a quick and easy coupling of the guidewires. It is to be understood, however, that other guidewire configurations to capture the guidewire 82 and draw it into the femoral sheath 20 (or vice versa) may be provided, including a snare structure, hook coupler or other coupling devices, without departing from the invention.

FIGURE 20 illustrates that the guidewire 82 from the right femoral artery in this example embodiment, has been captured and drawn through the elongated femoral sheath 20 and is attached to the contra limb of the collapsed graft 62. In this example embodiment, the right femoral artery is the contralateral femoral artery. It is to be understood, however, that the primary access may be instead through the right femoral artery, in which case the left femoral artery would be the contralateral femoral artery. Thus, in this example embodiment, the bottom contralateral marionette suture 78 is drawn by the contralateral guidewire 82 through the femoral sheath 20 and into the contralateral iliac artery and out through the respective femoral sheath 80, as illustrated in FIGURES 21 and 22. Note that although the bottom marionette suture 78 is attached to the bottom of the graft, to allow for removal of the sheath 34 when the graft is deployed into the guide catheter 22, suture 78 is doubled back and threaded out the top of sheath 34.

If deemed necessary or desirable, for example if the arterial typography is sufficiently irregular so that passage of the marionette suture may risk arterial surface trauma, a protective contralateral femoral guide catheter may be disposed through the introducer sheath or an elongated femoral sheath 180 may be used to extend at least into proximity of the distal end of the ipsi limb femoral sheath 20 as illustrated in FIGURE 23. The deployment procedure otherwise proceeds as described hereinabove with respect to a tube graft such that a monorail is deployed from the axillary access to the femoral access, a guide catheter fed thereover, and a femoral guidewire 24 fed to attach to the graft hanger in the manner described above. Next, the graft hanger can be fed through the axillary guide catheter and attached to the graft 62 already disposed in sheath 34 adjacent the femoral access. As illustrated in FIGURES 24 and 25, the bifurcated graft 62 would be placed initially above the renal arteries and thereafter the bottom marionette sutures 78,79 are pulled for the graft to be disposed in its final position (FIGURE 25). It should be noted that, for clarity, the central guidewires over which the graft and ultimately the stents are deployed have been omitted from FIGURES 24 and 25. A balloon angioplasty catheter may be used to radially expand the graft after it has left the deployment sheath. Typically, the spring arms of the graft hanger expand the top end of the graft but the balloon angioplasty catheter may be used to re-expand that end and/or the lower end(s) as well, if deemed necessary or desirable. The stents are only placed as and where needed and the specific lengths of the stent to be used may be likewise determined.

FIGURES 26-29 illustrate a technique for further, alternate embodiment(s) of the invention, with reference by way of example to bifurcated graft placement.

FIGURE 26 illustrates a guidewire capture technique similar to that described above with reference to FIGURES 1-3. At the stage of the procedure illustrated in FIGURE 26, the femoral sheath 20 has already been placed and the, e.g., magnetically tipped femoral guidewire 24 is disposed through the femoral sheath. Further, in contrast to the embodiment depicted in FIGURES 2 and 3, rather than the femoral guidewire capturing and drawing an axillary guidewire through the femoral sheath, the axillary guidewire (not shown in FIGURE 26) has captured and drawn the femoral guidewire 24 out through the axillary access and the axillary guide catheter 22 has been fed over the thus disposed femoral guidewire 24. Next, as also illustrated in FIGURE 26, the contralateral guidewire 82 is captured by a second axillary guidewire 110, and the mated guidewires 110 and 82 are then displaced through the axillary guide catheter 22 and out at the axillary access. In the illustrated embodiment, femoral guidewire 24 and femoral guidewire 82 are each magnetic tipped and may have opposite polarities, if deemed necessary or desirable. In the alternative, the guidewires may be tipped with other mechanical coupling devices and thus are not necessarily magnetically tipped guidewires.

FIGURE 27 depicts the femoral guidewires 24 and 82 extending through and out of the tip of the guide catheter 22. In the illustrated embodiment, a bifurcated graft 62 and graft hanger 130 are to be attached to the femoral guidewires 24 and 82 adjacent the axillary access and fed through the guide catheter 22 for graft deployment. In an example embodiment, monorails 84 and 86 are provided to mechanically couple the femoral guidewires 24 and 82 to the graft hanger. Further, to couple the femoral guidewires to the bifurcated graft, the bottom marionette sutures 78 and 79 are respectively attached, such as by knotting, to the femoral guidewires 82 and 24. In this example embodiment, monorails 84 and 86 are uniquely configured to be mechanically attached to the femoral guidewires 24 and 82 at one end, such as with magnet tips as illustrated in FIGURE 27, and are configured at the opposite longitudinal end thereof being mechanically attached to a graft hanger. In the illustrated example embodiment, the monorails 84 and 86 are secured to the graft hanger by a threaded engagement and thus complimentary threads are defined at the proximal ends of monorails 84 and 86 for engaging respective receptacles of the graft hanger.

FIGURE 28 schematically illustrates a bifurcated graft hanger 130 for receiving and deploying a bifurcated graft from adjacent the axillary access. The monorails 84 and 86 are coupled at the distal ends thereof to the femoral guidewires 24, 82, are coupled at the proximal ends thereof to the bifurcated graft hanger 130. In the illustrated example embodiment, the main body 138 of the bifurcated graft hanger 130 has first and second receptacles for receiving monorails 84 and 86, respectively disposed through each of the legs 60 of the bifurcated graft 62. The spring arms or limbs 140 of the bifurcated hanger 130 are coupled to the proximal end of the bifurcated graft with marionette sutures 44 in the manner as described above with reference to FIGURE 12. The combination of the bifurcated graft hanger and the bifurcated graft is disposed in a storage and deployment sheath 134 until deployment is imminent. Referring to FIGURE 29, the sheath 134 is disposed for loading the graft 62 and graft hanger 130 into the axillary guide catheter 22. An axillary guidewire 48 earlier coupled to the proximal end of the graft hanger can be pushed, and/or the femoral guidewires 24, 82 can be pulled, to facilitate this loading and displacement of the graft hanger and graft towards the target segment of the aorta for graft deployment. The graft legs 60 are ultimately respectively guided by the femoral guidewires 82 and 24 and the sutures 78 and 79 respectively attached thereto into the respective iliac arteries so that the bifurcated graft is properly located for stent placement as described above.

As will be appreciated from the foregoing, the axillary deployment described above with reference to bifurcated graft placement may also be used for tubular graft placement by drawing the femoral guidewire 24 upwards to the axillary access and coupling it to the graft hanger, either directly or with an intervening adapter, such as a monorail having one end tipped for coupling to the femoral guidewire 24 and the opposite end adapted for attachment to the graft hanger. Those skilled in this art and with the benefit of the above disclosure will readily appreciate other alternative guidewire and/or monorail feed alternatives for additional graft deployment options.

By providing a graft hanger that can be pushed and pulled into position and that suspends the graft during the final placement and until it is locked into place with stents, the surgeon has control of the graft the entire time, so there is no guess-work nor does the surgeon have to place the endograft in a hurry. Essentially, the surgeon never looses control of the graft at any point during the deployment process because the graft is always attached to a controlled deployment system, at each end, until it is seated in the circulation by placement of the stents.

While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for deploying an endograft in a target aneurysmal region of a major blood vessel comprising: providing an endograft having first and second longitudinal ends and 5 defining a lumen therebetween; providing an elongated introducer sheath; providing a graft hanger, said graft hanger including a main body having first and second longitudinal ends, a plurality of limbs extending from said main body beyond the second longitudinal end of the main body, and 0 means for coupling a guidewire to at least one of said first and second longitudinal ends of said main body; operatively coupling free ends of said hanger limbs to the first longitudinal end of said endograft; disposing said introducer sheath so that a distal end thereof is 5 disposed in a vicinity of the target aneurysmal region of said major blood vessel; holding said hanger limbs in a reduced diameter configuration; disposing said endograft in a radially collapsed configuration in said introducer sheath, with said graft hanger disposed upstream, in a blood flow o direction, of the endograft; displacing said introducer sheath while generally maintaining a position of said graft hanger thereby to deposit the endograft in said blood vessel; and releasing the hanger limbs to resiliently expand so that a circle circumscribed by the distal end of the hanger limbs increases, the expansion 5 of said hanger limbs expanding said graft towards an expanded diameter configuration thereof.

2. A method for deploying as in claim 1 , further comprising, after said releasing, disposing at least one stent structure in said expanded endograft to o secure said endograft in position in said blood vessel.

3. A method for deploying as in claim 1 , further comprising, after said releasing, detaching said hanger limbs from said graft hanger and removing said graft hanger from said blood vessel.

4. A method for deploying as in claim 1 , wherein said disposing said disposing said endograft with said graft hanger in said introducer sheath comprises disposing a guide catheter through said introducer sheath, placing said graft hanger in said guide catheter and displacing said guide catheter through said introducer sheath.

5. A method for deploying as in claim 4, wherein said graft hanger is operatively coupled to said endograft by securing each said hanger limb to said first end of said endograft with suture filaments.

6. A method for deploying as in claim 5, wherein said suture filaments extend through said guide catheter for remote adjustment of said operative coupling of said hanger limbs to said endograft.

7. A method for deploying as in claim 6, wherein said guide catheter comprises a multi-lumen catheter having a central lumen for selectively receiving said graft hanger and having a plurality of peripheral lumens, each said suture filament being threaded through a respective said peripheral lumen for said remote adjustment of said operative coupling of said hanger limbs to said endograft.

8. A method for deploying as in claim 1 , wherein said graft hanger is operatively coupled to said endograft by securing each said hanger limb to said first end of said endograft with suture filaments.

9. A method for deploying as in claim 1 , further comprising securing a suture filament to said second longitudinal end of said endograft and extending said suture filament through said introducer sheath for selectively controlling a position of said endograft remotely.

10. A method for deploying as in claim 1 , wherein a guide wire is secured to each longitudinal end of said graft hanger and said guide wires are displaced to displace said graft hanger with respect to said introducer sheath.

11. A method of deploying as in claim 1 , wherein said endograft is a bifurcated graft.

12. A method for deploying as in claim 1 , further comprising: inserting said introducer sheath as a femoral introducer sheath and inserting an axillary introducer sheath; disposing first and second guidewires respectively through said femoral and axillary introducer sheaths; operatively coupling distal ends of said guide wires to each other; and displacing said coupled guide wires through one of said sheaths.

13. A graft hanger for deploying and expanding an endograft comprising: a main body having first and second longitudinal ends; a plurality of resilient limbs extending from said main body beyond the second longitudinal end of said main body, said resilient limbs terminating distally in free ends remote from said main body, said resilient limbs being resiliently collapsible to a first position wherein a distance between diametrically opposed said limbs is X and, when an external force collapsing said resilient limbs are released, said resilient limbs expand radially outwardly so that a distance between diametrically opposed limbs is Y, Y being greater than X.

14. A graft hanger as in claim 13, wherein Y is at least about 10 times X.

15. A graft hanger as in claim 13, wherein a diametric distance between said distal ends of said limbs in the absence of external forces is at least about 3 cm.

16. A graft hanger as in claim 13, wherein said limbs have a length in a range of 3-5 cm.

17. A graft hanger as in claim 13, wherein said graft hanger main body has a diameter of about 2-3 mm.

18. A graft hanger as in claim 13, further comprising means for connecting at least one guide wire to said main body.

19. A graft hanger as in claim 18, wherein said means comprises a threaded bore defined in at least one end of said main body.

20. A graft hanger as in claim 19, wherein a threaded bore is defined in each longitudinal end of said main body.

21. A graft hanger as in claim 18, wherein means for connecting are provided at each longitudinal end of said main body.

22. A graft hanger as in claim 13, wherein said distal ends of said hanger limbs include means for operatively coupling said hanger limbs to an endograft.

23. A graft hanger as in claim 22, wherein said means comprises a bore defined through said limb for receiving a filament.

24. A graft hanger as in claim 13, wherein said hanger limbs are symmetrically disposed about the circumference of the hanger main body.

25. A graft hanger as in claim 24, wherein there are four hanger limbs.