Patent ID: 12193676

DETAILED DESCRIPTION OF THE INVENTION

FIG.1illustrates the anatomy of an infrarenal abdominal aortic aneurysm comprising the thoracic aorta (TA) having renal arteries (RA) at an end above the iliac arteries (IA). The abdominal aortic aneurysm (AAA) typically forms between the renal arteries (RA) and the iliac arteries (IA) and may have regions of mural thrombus (T) over portions of its inner surface(S).

Referring now toFIG.2, a system10constructed in accordance with the principles of the present invention for delivering a double-walled filling structure12(also referred to as an endograft in this disclosure) to an aneurysm includes the filling structure12disposed over a radially expandable endoframe27(also referred to as a scaffold, stent or scaffolding in this disclosure), both of which are then mounted on a delivery catheter14having an expandable element16, typically an inflatable balloon, at its distal end. Expandable element16traverses the entire length of the endoframe27so that the endoframe27may be radially expanded upon expansion of the expandable element16. Endoframe27traverses the entire length of filling structure12and most of endoframe27is covered by filling structure12, however endoframe27also has proximal and a distal regions that extend uncovered beyond the filling structure12. One of skill in the art will appreciate that lengths of the filling structure, endoframe and expandable element may be adjusted as required and thus the relative lengths are not limited to those disclosed above. Further details about the double-walled filling structure are disclosed in U.S. Patent Publication No. 2006/0212112 and preferred embodiments of an endoframe scaffold are disclosed in U.S. Provisional Patent Application No. 61/029,225 and U.S. patent application Ser. No. 12/371,087, both of which the entire contents are incorporated herein by reference. The catheter14will comprise a guidewire lumen18, a balloon inflation lumen or other structure for expanding other expandable components, and a filling tube20for delivering a filling medium or material to an internal space22of the double-walled filling structure12. The internal space22is defined between an outer wall24and inner wall26of the filling structure. Upon inflation with the filling material or medium, the outer wall24will expand radially outwardly, as shown in broken line, as will the inner wall26, also shown in broken line. Expansion of the inner wall26defines an internal lumen28. The expandable balloon or other structure16will be expandable to correspondingly expand the endoframe27to provide support and to shape an inner surface of the lumen28. In this embodiment, the expandable balloon is substantially cylindrically shaped and therefore the lumen will also be cylindrically shaped. In other embodiments, the balloon may be pre-shaped to more precisely match the curvature of the vessel. For example, when treating an aortic aneurysm, a tapered, pre-shaped or curved balloon may be used so that the lumen substantially matches the aorta. Various balloon configurations may be used in order to match vessel tortuosity. Pre-shaped, curved or tapered balloons may be used in any of the embodiments disclosed herein in order to obtain a desired lumen shaped.

In a particular and preferred aspect of the present invention, a pair of double-walled filling structures will be used to treat infrarenal abdominal aortic aneurysms, instead of only a single filling structure as illustrated inFIG.1. A system comprising such a pair of filling structures is illustrated inFIG.3which includes a first filling structure112and a second filling structure212. Each of the filling structures112and212are mounted on delivery catheters114and214, respectively and each system also has a radially expandable endoframe scaffold127,227. The components of the filling structures112and212, the endoframes127,227and delivery catheters114and214are generally the same as those described previously with respect to the single filling structure system10ofFIG.1. Corresponding parts of each of the filling systems112and212will be given identical numbers with either the 100 base number or 200 base number. The filling structures112and212will generally be positioned adjacent each other within the aneurismal space to fill that space, as will be described with specific reference toFIGS.4A-4Ibelow.

FIGS.4A-4Iillustrate an exemplary use of the system inFIG.3for treating an infrarenal abdominal aortic aneurysm AAA with or without mural thrombus T. An optional sheath may be disposed over the scaffold and/or filling structure as seen inFIG.10A. InFIG.4Aa pair of guidewires (GW) will first be introduced preferably percutaneously or by surgical cut down, from each of the iliac arteries (IA) and advanced across the aneurysm toward the renal arteries (RA). Referring now toFIG.4B, the first delivery catheter114having expandable balloon116will then be positioned over one of the guidewires GW to position the double-walled filling structure112across the aortic aneurysm (AAA) along with scaffold127. The second delivery catheter214having expandable balloon216is then delivered over the other guidewire GW to position the second filling structure212adjacent to the first structure112across the aneurysm (AAA) along with scaffold227, as illustrated inFIG.4C. If either of the delivery catheters114,214include sheaths covering their respective scaffold and/or filling structure, the sheath (not illustrated) will be retracted. Typically, one of the filling structures112,212and associated balloons116,216will be expanded first along with the corresponding scaffold127,227, followed by the other filling structure, scaffold and balloon. In some embodiments, both balloons may be radially expanded simultaneously thereby also expanding the filling structures and scaffolds simultaneously.

Alternatively, one or both filling structures112,212may be filled with a hardenable material and then the filling structures112,212are radially expanded along with the corresponding scaffold127,227. In still other embodiments, combinations of filling and expanding may be performed in different order depending on physician preference and aneurysm anatomy. In some embodiments, an optional unfurling of the filling structure may be performed prior its filling and radial expansion. In this optional step, once the delivery system is positioned across the aneurysm, the filling structure may be filled with CO2gas, contrast media, saline or other fluids to unfurl the filling structure away from the delivery catheter thereby helping to ensure more uniform filling later on. During unfurling, the filling structure may be partially filled or fully filled so that it conforms to the inner aneurysm wall. Once unfurled, the fluid may be removed from the filling structure and it may be filled with the hardenable material to expand and conform to the aneurismal space between the lumens and the inner aneurysm wall. Pressure relief valves such as those described below may also be used to ensure that the filling structure is not over filled.

In another variation of the method, an optional contrast pre-filling step may be utilized. In this embodiment, after the delivery catheter is positioned across the aneurysm and the endoframe has been radially expanded, the filling structure may be pre-filled with contrast media so as to permit observation of the filled filling structure under a fluoroscope relative to the aneurismal sac. Additionally, the pre-filling step allows the physician to record the pressure and volume of the contrast media used for optimal filling of the filling structure and this will provide an estimate of volume and pressure to be used when filling the filling structure with the hardenable filling material. In order to prevent overfilling of the filling structure, any of the pressure relief valves disclosed below may also be used to bleed off excess fluid from the filling structure.

FIG.4Dillustrates inflation of balloon116along with scaffold127in addition to expansion and filling of filling structure112. The filling structure112and balloon116are expanded and inflated to fill generally half of the aneurismal volume, as illustrated inFIG.4D. Filling and expansion can generally be carried out as described in U.S. Patent Publication No. 2006/0212112 for one filling structure, except of course that the filling structure112will be expanded to occupy only about one-half of the aneurismal volume. U.S. Patent Publication No. 2006/0212112 discloses filling of one filling structure in more detail including pressures, filling materials and other details, the entire contents of which have previously been incorporated herein by reference. After the first filling structure112has been filled, the second filling structure212may be filled and expanded along with scaffold227, as illustrated inFIG.4E.FIG.4Ealso illustrates a cut away view of the expanded scaffolds127,227within the filled filling structures112,212. The upper ends of the balloons116and216will conform the tubular lumens of the filling structures against the walls of the aorta as well as against each other, while the lower ends of the balloons116and216will conform the tubular lumens into the respective iliac artery, IA. The expanded scaffold127not only provides support to filling structure112, but also creates and shapes a lumen for blood passage from the aorta to one of the iliac arteries. Similarly, expanded scaffold227also provides a lumen for blood passage from the aorta into the other iliac artery. In some protocols filling of the filling structures (either both filled simultaneously or one after the other) may be performed before, during or after radial expansion of the balloons and the scaffolding127,227(either both expanded simultaneously or one after the other). Additionally, as discussed above with respect toFIG.2, the scaffolds127,227may be radially expanded using a cylindrically shaped balloon to form a substantially cylindrically shaped lumen. Curved, tapered or pre-shaped balloons may also be used to expand the scaffolds127,227, thereby forming a lumen that also is curved, tapered or shaped. The curved, tapered or pre-shaped balloon may be selected to match the anatomy of the vessel in which the scaffold and endograft is placed. Pre-shaped, curved or tapered balloons may be used in any of the other embodiments disclosed herein in order to obtain a desired lumen shape.

After filling the filling structures112and212as illustrated inFIG.4E, the filling materials or medium will be cured or otherwise hardened as described in U.S. Patent Publication No. 2006/0212112 and the delivery catheters114and214removed, respectively. The hardened filling structures along with the expanded scaffolds127,227will then provide a pair of tubular lumens opening from the aorta beneath the renal arteries to the right and left iliac arteries, as shown more clearly in broken line inFIG.4F. The ability of the filling structures112and212to conform to the inner surface(S) of the aneurysm, as shown inFIG.4F, helps the structures to remain immobilized within the aneurysm with little or no migration. Immobilization of the filling structures112and212may be further enhanced by providing any of the surface features described in U.S. Patent Publication No. 2006/0212112 which has been incorporated herein by reference.

The double filling structure embodiments will include at least one separate scaffold deployed within each of the tubular blood flow lumens. The scaffolds will generally be endoskeletal structures that lay the foundation for new lumens, and will be deployed within the tubular lumens of the double-walled filling structures using balloon or other expansion catheters (in the case of malleable or balloon-expandable scaffolds) and an optional retractable constraining sheath.FIG.4Gmore clearly shows the first scaffold127disposed within the tubular lumen of the first filling structure112while a second scaffold227is disposed in the tubular lumen of the second filling structure212. As illustrated, in this exemplary embodiment, the scaffolds are balloon expandable structures which extend into the iliac arteries IA at the lower end of the filling structures. In other embodiments, the scaffolds may be self-expanding stent-like structures fabricated from a shape memory alloy such as Nitinol.

Referring now toFIG.4H, first and second scaffolds127and227may extend upwardly on the aortic side of the first and second filling structures112and212. When the scaffold structures extend into the thoracic aorta TA, it will usually be desirable that they be expanded so that they conform to each other along a plane or region of contact. For example, as shown inFIG.4I, the upper ends of the scaffolds127,227may be formed preferentially to have D-shaped cross-sections when expanded, although other cross-sections such as elliptical, circular, etc. may be formed. Thus, flat faces258and260will engage each other with the remaining portion of the stent conforming to the inner wall of the aorta. In this way, most of the cross-sectional area of the aorta will be covered with the scaffold, thus enhancing blood flow through the filling structures. Other configurations are disclosed in U.S. Patent Publication No. 2006/0212112 previously incorporated herein by reference.

In the exemplary embodiment ofFIGS.4A-4I, the scaffold and filling structure are both disposed coaxially and generally concentrically over an expandable member coupled to a delivery catheter and the entire system is delivered to the aneurysm at one time.FIG.5shows a similar coaxial and concentric system300for treating aneurysms where a filling structure308, also referred to as an endograft is coaxially disposed over stent-like scaffold306, both of which are then coaxially and concentrically positioned over a radially expandable balloon304which is coupled to the distal region of a catheter shaft302. Proximal and distal portions of scaffold306extend uncovered by filling structure308and a filling tube310allows a fluid to be delivered to the filling structure308. While this embodiment is promising, in certain situations, the filling structure may move relative to the endoframe during delivery, thereby resulting in inaccurate placement of one or both devices. It would therefore be advantageous to provide a more effective way of coupling the filling structure with the endoframe to minimize such movement and to facilitate more accurate delivery of the scaffold and endograft to the treatment site.FIG.29illustrates an exemplary embodiment that employs a releasable coupling mechanism to help minimize such movement. InFIG.29, the distal region of a delivery catheter having a filling structure and an endoframe disposed thereover is highlighted. Filling structure2902is disposed over an endoframe2904, both of which are also disposed over a radially expandable balloon2906coupled to catheter shaft2908. The distal end of catheter shaft2908includes an atraumatic tapered nosecone2910having a receiving aperture2920. The releasable coupling mechanism includes a lockwire2918that runs substantially parallel with catheter shaft2908, with the distal end of the lockwire2918disposed in the receiving aperture2920in nosecone2910. The releasable coupling mechanism also uses a tether2914. Tether2914is releasably coupled with the lockwire2918, the filling structure2912and the catheter shaft2908, thereby minimizing relative motion of the endoframe2904to the filling structure2902during delivery. The tether may be a thin wire fabricated from metal or a polymer or it may be a suture or other filament-like material. Coupling is accomplished by passing one end of the tether2914through a tether loop2912attached to the filling structure2902and one end of the tether is then releasably coupled with the lockwire2918using a releasable knot, here a constrictor knot2916. Constrictor knots are well known in the art and may be seen in greater detail inFIGS.30A-30B. The opposite end of the tether is secured to the distal region of the delivery catheter2922with a knot such as a constrictor knot, or bonded, welded or otherwise fixed to the catheter shaft. This configuration helps keep the filling structure2902from moving relative to the endoframe2904and the delivery catheter2908during delivery.FIG.29illustrates a single tether coupled with a single tether loop. Using the tether/pullwire coupling system, movement of the filling structure relative to the endoframe is limited to ±5 mm preferably, and more preferably to ±3 mm and the endoframe/filling structure can be positioned in the aneurysm to within ±7 mm of a target implantation site, and more preferably to within ±5 mm of the target site.

In use, once the filling structure2902and the endoframe2904have been delivered to a desired position, the lockwire2918may be retracted proximally so that its distal tip disengages from aperture2920and the lockwire is removed from under the constrictor knot2916allowing the knot to unfurl. This de-couples the endoframe2902from the delivery catheter2908so that the two may be separated from one another. One end of the tether remains coupled with the catheter so that the tether may also be removed from the body.

The embodiment ofFIG.29only illustrates a single tether. In other embodiments, multiple releasable coupling mechanisms using tethers may be coupled with multiple tether loops. For example, two, three, four or more releasable coupling mechanisms having two, three, four or more tethers may be disposed circumferentially and optionally symmetrically around the catheter and filling structure coupled with a matching number of tether loops coupled with the filling structure. In other embodiments, one, two, three, four, or more releasable coupling mechanisms using tethers may be coupled to both the proximal and distal ends of the filling structure with tether loops on the proximal and distal ends of the filling structure.FIG.31illustrates an exemplary embodiment of a device having two releasable coupling mechanisms including tethers. InFIG.31a delivery sheath3102is disposed over the endoframe3118and filling structure3104during delivery to the aneurysm, typically over a guidewire GW. Once delivered to the aneurysm, the endoframe3118and the filling structure3104are advanced and exposed from the delivery sheath3102(or the delivery sheath is retracted). Two releasable coupling mechanisms having two tethers3110and3128are used to help couple the filling structure3104with the endoframe3118. A first tether3110passes through a tether loop3122attached to the filling structure3104while one end of the tether is releasably connected to the lockwire3108using a knot3124such as the constrictor knot previously disclosed above. The other end3114of the tether3110is coupled with a distal portion of delivery catheter3116or nose cone3106. A second tether3128passes over the lockwire3108and through a second tether loop3126attached to the other end of the filling structure3104. The second tether3128is then releasably coupled with the fill tube3132extending from the filling structure3104using a knot3130such as a constrictor knot. The fill tube3132allows the filling structure3104to be filled with hardenable medium from outside the patient's body. The lockwire3108runs substantially parallel with the delivery sheath3102and is disposed under the filling structure3104. The distal end of the lockwire3108is releasably received in an aperture3112in tapered nosecone3106and the proximal end may be manipulated by the physician from outside the patient's body. In addition to helping prevent movement of the filling structure relative to the scaffold, the second tether3128helps to prevent release of the fill tube3132from the filing structure3104, thus providing a fail safe mechanism prior to filling, and during filling or re-filling of the filling structure and until the procedure is over and it is desired to separate the filling tube from the filling structure. Endoframe3118is crimped over balloon3120which is coupled with the delivery catheter shaft3116. In these exemplary embodiments, a tether is used in the releasable coupling mechanism to prevent unwanted movement of the filling structure relative to the scaffold. One of skill in the art will appreciate that other releasable coupling mechanisms may be used and therefore the coupling mechanism is not limited to tether embodiments. Additionally, the tether may be used as a releasable coupling mechanism in any of the embodiments disclosed in this specification.

The coupling mechanism described inFIG.31also allows positioning of the filling structure relative to the endoframe by movement of the delivery catheter, as illustrated inFIGS.32A-32B. InFIG.32A, depending on how taut the tethers3110and3128are, the delivery catheter3116may be advanced or retracted as indicated by the arrows to position the endoframe3118and delivery catheter3116relative to the filling structure3104. Similarly, inFIG.32B, the delivery catheter3116may be advanced into the filling structure3104or retracted away from the filling structure3104as indicated by the arrows. This embodiment may be used when in situ adjustment is desired or during “serial deployment” where either the filling structure or the endoframe is deployed before the other and then the two components are aligned in the aneurysm, as will be discussed in greater detail below. In addition to serial delivery of a scaffold and endograft, the releasable coupling mechanisms described herein (e.g. the tether embodiments described above) may also be used in parallel delivery of the two components as will be discussed in greater detail below. Thus, releasable coupling mechanisms such as tethers may be used in any of the embodiments disclosed herein. Sometimes, the lockwire will be covered with a support post. InFIG.35, a loop3514coupled with the filling structure3502is fed into an aperture3516of a support post3512. A lockwire3510is fed through the support post3512and through the loop3514, thereby coupling the filling structure3502with the lockwire3510. The distal end of the lockwire3510is received in an aperture3508on nosecone3506of the delivery catheter3504. This configuration prevents the support post from having a free end that could extend and cause damage or trauma to the vasculature. Retraction of the lockwire3510past the aperture3516releases the loop3514from the lockwire3510.

In other embodiments, the filling structure may be coupled more directly with the endoframe. For example, inFIG.33, the endoframe3304includes eyelets3306near it's proximal and distal ends. Tether loops3308may then be looped through the eyelets3306and secured to the filling structure3302. This way, the filling structure3302will be fixed relative to the endoframe as long as the tether loops are taut. Generally, this coupling mechanism will allow about ±5 mm and more preferably ±3 mm of relative movement between the filling structure and the endoframe. Also, the filling structure and endoframe should be positionable within ±7 mm and more preferably between ±5 mm of a target position within the aneurysm of the filling structure3302.

In place of tethers coupled with the filling tube (such as tether3128inFIGS.32A-32B), spring loaded arms may be used. InFIG.34, filling structure3402includes a filling tube3410for filling the filling structure with hardenable medium. A pair of spring arms3414are coupled with the filling tube3410at one end, and the opposite ends of the arms3414are coupled with the filling structure3402. The ends are wrapped around a loop3412coupled with the filling structure3402. In this embodiment, the arms are wire-like elements made from spring temper metal such as stainless steel or superelastic nitinol, although other materials could be used such as a resilient polymer. Since the filling structure is coupled with the filling tube, they are fixed to one another and relative movement is not possible. The arms3414are advantageous since upon deployment from a constraining sheath (not illustrated), the arms radially expand outward, facilitating opening of the filling structure so it is may receive the delivery catheter3406having an endoframe3404mounted over a balloon3408. Again, this embodiment may be used when the filling structure and the endoframe are delivered separately, as discussed below.

In addition to the potential challenge of minimizing movement of the endoframe relative to the filling structure, the embodiment described inFIG.5may present other challenges. For example, because of the stackup of multiple elements on top of one another, the distal region of system300has a relatively large profile which can make it difficult to insert percutaneously into the patient's vasculature and in some cases (e.g. through tortuous vessels or through stenotic regions) it also is difficult to advance to the aneurysm. Therefore, other delivery system configurations are possible which may help reduce profile and facilitate delivery. These delivery systems have an outer diameter preferably ranging from 10 French to 18 French, and more preferably have an outer diameter ranging from 12 French to 16 French.

FIG.6illustrates an alternative embodiment where the system320utilizes independent delivery of the filling structure and the scaffold. InFIG.6, a filling structure326is disposed over a balloon324which is coupled to a first delivery catheter322. A filling tube328allows the filling structure326to be filled with a hardenable material. A second delivery catheter330carries a second balloon332having a scaffold334disposed thereon. In this embodiment, the endograft may be delivered to the aneurysm first where it is expanded and filled via filling tube328and then the first catheter322is removed from the filling structure326. The second catheter332is then advanced into the lumen created by the filling structure326and then balloon332is expanded thereby correspondingly expanding scaffold334within filling structure326. Alternatively, after filling structure326has been expanded and filled, delivery catheter322may be removed from the patient's body and scaffold334may be mounted on the same delivery catheter322for delivery and expansion into the filling structure326. This alternative embodiment provides some advantages over the embodiment ofFIG.5such as having a lower profile but still has challenges such as the increased cost and waste associated with using two separate delivery catheters or an increased procedure time to deliver and deploy the filling structure and scaffold independently of one another. One possible solution is to provide a delivery catheter having two independently expandable balloons disposed on a delivery catheter. The balloons are separated from one another by a predetermined distance. A scaffold is placed over one balloon and an endograft is placed over the second balloon. Thus, a single catheter may be used to deliver both the graft and scaffold to the aneurysm where the graft and scaffold are then independently deployed into the aneurysm.

Another embodiment which reduces the need for two delivery catheters and also reduces procedure time by eliminating the need to remove the catheter from the patient and then mount a scaffold thereover is illustrated inFIG.7. InFIG.7, a single delivery catheter carries both scaffold and filling structure to the aneurysm while still providing a system with reduced delivery profile. Delivery system350includes a delivery catheter352having an expandable balloon358. Scaffold360is mounted directly over the balloon358and the filling structure354is positioned distal to the scaffold360such that the two implants are axially separated from one another and a gap or spacing362separates them. The releasable coupling mechanisms described above, including the tether embodiments may be used to limit movement between the scaffold and the filling structure. The delivery catheter352may be advanced to the aneurismal treatment site such that filling structure354traverses the aneurysm. The filling structure354may be filled via filling tube356so that it conforms to the aneurysm and then scaffold360may be advanced distally in the direction of arrow364so that is received in the lumen of filling structure354. Balloon358may then be radially expanded so as to expand scaffold360into the inner wall of filling structure354. In an alternative embodiment, after filling structure354is positioned across the aneurysm, scaffold360may be advanced into the lumen of filling structure354. Both are then radially expanded by expansion of balloon358and the filling structure is filled either before, during or after radial expansion. System370ofFIG.8is similar to that of system350inFIG.7except that the relative positions of the scaffold360and filling structure354have been reversed. This time, in the embodiment ofFIG.8, scaffold360is retracted proximally in the direction of arrow366into the lumen of filling structure354. One of ordinary skill in the art will appreciate the motion of the components is relative, thus instead of advancing a first component into a second component, the second component may be retracted over the first component. Similarly, retraction of a first component into a second component may also be achieved by advancing the second component over the first component.

Yet another embodiment that helps reduce delivery profile is illustrated by system390inFIG.9. InFIG.9, a filling structure392having filling tube398is disposed over delivery catheter396and axially separated from radially expandable balloon394by a spacing399. In this embodiment, the filling structure392may be delivered to the aneurysm where it is filled and balloon394is expanded to help form the lumen in filling structure392. Alternatively, the filling structure may be retracted over balloon394either before, during or after delivery to the aneurismal treatment site and then it may be expanded and filled. A separate scaffold (not illustrated) may then be delivered and deployed in the lumen created by the inner wall of filling structure392. A releasable coupling mechanism, such as the tether embodiments previously described above may also be included in this embodiment to minimize movement of the filling structure relative to the scaffold.

Some delivery systems may include a sheath. Any of the embodiments previously described may include a sheath in order to protect the scaffolding and/or the filling structure. In some embodiments where the scaffolding is self-expanding, the sheath acts as a constraint to keep the scaffolding from self-expanding.FIG.10Aillustrates a delivery system having a balloon406disposed over a catheter shaft404. A balloon expandable scaffolding408is disposed over the balloon406and a filling structure410is also disposed over the catheter shaft404axially separated from the balloon406. An outer sheath402is disposed over both the scaffolding408and the filling structure410. Moving the sheath402away from the scaffolding408exposes the scaffolding408and/or filling structure410so that either may be radially expanded by balloon406or allows expansion of filling structure410due to filling.FIG.10Aalso illustrates an optional pusher tube412having a distal end that can engage the proximal end of the endograft. The pusher tube keeps the endograft from moving as the outer sheath402is retracted and also helps to support the endograft and prevent it from collapsing during sheath retraction. The pusher tube412and the sheath402may be extruded using manufacturing techniques well known to those of ordinary skill in the art and may be fabricated from a number of polymers such as polyethylene, polyurethane, Teflon, PVC, nylon and the like.

FIG.10Billustrates another sheath embodiment similar to the embodiment ofFIG.10A, except in this embodiment the sheath has a tapered distal end. Because the balloon406and scaffolding408are distal relative to the filling structure410and because of the larger profile of the endograft filling structure410relative to the scaffolding408, a step exists between the filling structure410and the scaffolding408. Tapered region403in sheath402provides a smoother transition between these two regions. In order to facilitate retraction of the sheath over the filling structure410, the tapered tip403may be perforated or longitudinally slit. Thus, as sheath402is retracted and as the tapered region403begins to engage filling structure410, the slits or perforations will open up allowing the smaller diameter sheath tip to pass over the filling structure410. In a preferred embodiment, two slits approximately 180 degrees apart may be imparted into the sheath tip, although it will be recognized that additional slits or even a single slit may be used.

Other variations on the orientation of the balloon, filling structure and scaffolding may also be employed. For example, in some embodiments the endoframe scaffolding and filling structure may be mounted coaxially over a catheter shaft either proximal of or distal to a balloon. The scaffolding and filling structure are positioned at the treatment site and then the balloon is positioned within the scaffolding and filling structure and expanded. In a variation of this embodiment, a thin split tubular liner may be positioned over the balloon and passes through the inner diameter of the filling structure. The thin liner acts as a guide for the balloon during use. Thus, as the balloon is axially positioned within the scaffolding and filling structure, the thin liner guides the balloon through the inner diameter of the scaffolding. When the balloon is expanded, the thin liner splits along perforations or slit regions to allow radial expansion thereof.

For example, inFIGS.36A-36B, a smooth sheath or covering3608may be disposed over all or a portion of the endoframe3606and balloon3610. This is useful in embodiments where the endoframe3606and catheter shaft3604are advanced into the filling structure3602(e.g.FIG.7) or where the endoframe3606and catheter shaft3604are retracted into the filling structure (e.g.FIG.8). Covering all or a portion of the balloon3610and endoframe3606allows both to easily be received into the filling structure3602without binding or damaging either component. When the balloon is inflated, the cover3608will be pushed away from and off the endoframe3606and balloon3610, allowing full expansion as seen inFIG.36B.

FIG.37illustrates another embodiment using a sheath or cover. InFIG.37, the entire endoframe3704and balloon3708are covered by the sheath3702to facilitate smooth entry of the endoframe3704into the filling structure3706when the catheter shaft3710is moved in the direction of the arrow.FIG.38illustrates still another embodiment using a sheath. InFIG.38, a sheath or sleeve3802not only covers the endoframe3804and balloon3808, but extends all the way through the filling structure3810. Thus, when the delivery catheter3806is advanced, the endoframe3804easily slides through the sleeve3802and avoids rubbing against the inner wall of the filling structure3810. The sleeve3802may then be easily retracted and removed prior to deployment of the endoframe and filling structure.

A split sheath or a perforated sheath may also be used to facilitate deployment of the device. For example,FIG.52Aillustrates a filling structure5210having a filling tube5214disposed over a scaffold5212which is carried by a balloon5208on a delivery catheter shaft5206having a distal nosecone5204. The delivery catheter is delivered over a guidewire GW and covered with a sheath5202during delivery. Upon deployment, the sheath5202is retracted and the filling structure5210is filled and endoframe5212is expanded with balloon5208. The delivery catheter5206is then retracted away from the expanded endoframe5212and expanded filling structure5210as seen inFIG.52B. In some situations, the physician may desire to further expand the endoframe5212with a larger size balloon. This requires that the delivery catheter5206be removed and replaced. However, the nosecone5204cannot be retracted into the sheath5202due to interference with the filling tube5214. A tapered split sheath or a tapered perforated sheath may be used to overcome this challenge.FIG.52Cillustrates a tapered split sheath5216. The tapered split sheath5216allows for a smaller nosecone5204, which can pass through the sheath. Because the sheath5216is tapered at the tip, it must split to pass over the filling structure5210. This allows the delivery catheter to be retracted from the patient and replaced with a different catheter having a different balloon size for post-dilation of the endoframe.

In other embodiments, a tether line may be used to help guide movement of the filling structure relative to the scaffolding.FIGS.11A-11Billustrate the use of such a tether line. InFIG.11A, a delivery system420includes an elongate flexible shaft422having a balloon430disposed near the distal end of the shaft422. A stent-like scaffolding432is carried by the balloon430. A filling structure436with filling tube438is also disposed over shaft422. Filling structure436has four eyelets434which serve as guides for tether lines428to pass through. Tether lines428extend from the proximal end of delivery system420, through eyelets434and are coupled to nosecone426. Nosecone426is coupled to shaft424which is movable relative to shaft422. Shaft422is retracted over shaft424such that balloon430and scaffold432are slidably received by filling structure436.FIG.11Bshows retraction of scaffolding432into filling structure436with a longer length of shaft424exposed. Tether lines428help guide the filling structure436so that it mates with scaffolding432and is retracted into the filling structure432. In this exemplary embodiment, four eyelets434are used, although more or less may also be used. The eyelets434may be integral with the filling structure436or they may be separate components bonded or otherwise attached thereto. Once the scaffolding has been retracted into a desired position within filling structure436, the tether lines428may be pulled from nosecone426and away from the filling structure436so that it may be expanded and filled in the aneurysm.

FIGS.12A-12Billustrate an alternative embodiment of a system450employing tether lines. InFIGS.12A-12B, tether lines are used to pull the filling structure toward the scaffolding so that the two components are properly aligned. InFIG.12A, a catheter shaft456carries a balloon460disposed near the shaft's distal end and a scaffolding462is disposed over the balloon. A nosecone454is coupled to the distal end of shaft456and a filling structure452having a filling tube464is disposed over the catheter shaft adjacent the balloon460and scaffold462. The nosecone has a taper457on the proximal end as well as an optional taper on the distal end, that way the nosecone helps guide the catheter as it is being advanced through the vasculature and the proximal taper helps the catheter pass through the filling structure as the catheter is being retracted away from the filling structure. Tether lines458are removably coupled to filling structure452and extend distally to nosecone454. Tether lines458extend through nosecone454and then extend proximally through a lumen in shaft456(not shown) until the tether lines458exit the proximal end of the catheter shaft456. As the proximal portion of tether lines458are pulled proximally away from the aneurysm, filling structure452is advanced until it is properly positioned over the scaffolding462and balloon460. The tether lines may then be pulled free from filling structure452and pulled into nosecone454as seen inFIG.12B. The filling structure452and scaffold462may then be filled and expanded into the aneurysm. In an alternative embodiment, the shaft456and scaffolding462may be retracted into filling structure452.

A hitch may also be used to move the filling structure relative to the scaffolding.FIGS.22A-22Billustrate an exemplary embodiment of a hitch. InFIG.22Aeyelet or suture loop702is coupled with a filling structure712(FIG.22B). Here, one loop is disclosed, although additional suture loops may also be used. The suture loop702is used to hitch the filling structure712with a hypotube760so that the filling structure may be advanced. Hypotube706runs substantially parallel with the delivery catheter shaft (not illustrated here). A distal portion of the hypotube706is skived708to create a receptacle for receiving the suture loop702. A lockwire704passes through the hypotube706and through the suture loop702, thereby locking the suture loop702to the hypotube706. When the hypotube706is advanced distally suture loop702is tensioned and thus, the filling structure may be advanced distally over the scaffolding710. Once the filling structure712is placed in the desired position relative to scaffolding710, the lockwire704may be retracted proximally from the hypotube706releasing the suture loop702from the skived region708. The hypotube706and lockwire704may then be retracted away from the filling structure712and removed from the patient.

Sometimes, it may be desirable to increase the columnar strength of the endograft in order to prevent it from buckling or otherwise collapsing. Suturing the endograft to the scaffold may be used to help keep the two structures coupled together. Some embodiments utilize wires or metal frames in the filling structure or attached thereto in order to provide additional support. A pocket or receptacle on the filling structure may also provide enhanced column strength.FIGS.23A-23Cillustrate an exemplary embodiment with a pocket.

InFIG.23A, filling structure730comprises a pocket or receptacle formed in a wall of the filling structure730, near its distal end. The pocket734may be made from the same material as the filling structure730, or it may be another resilient material. The pocket734is generally closed along three sides and has one end open, preferably proximally oriented. The opening is sized to slidably receive a tensioning tube, rod or hypotube732. In use, the tensioning tube732is inserted into the pocket734until its distal end bottoms out.FIG.23Bshows the tensioning tube732traversing the unrolled, flattened filling structure730substantially parallel to the longitudinal axis thereof. A filling tab736is coupled with a proximal end of the filling structure730and a filling tube738is fluidly connected to the filling tab736. The filling tube738extends proximally so that the filling structure730may be filled from outside the patient's body. The filling tube738may be used to apply tension to the proximal end of the filling structure730and thus the filling structure730is captured between the pocket734on the distal end of the filling structure730and the filling tube738on the proximal end. In an alternative embodiment, the proximal end of the filling structure730may utilize the hitch previously disclosed inFIGS.22A-22B.FIG.23Cshows a pocket734on the distal end of filling structure730and a suture loop740on the proximal end of filling structure730. Tensioning tube732is inserted into pocket734and also uses the hitch ofFIGS.22A-22Bto capture suture loop740. In either embodiment, once the filling structure is delivered to the treatment site, filled and deployed, the tensioning tube732may be retracted from the pocket734and the hitch released, thereby disengaging the tensioning tube732from the filling structure730.

Another exemplary embodiment of a filling structure and scaffolding delivery system is seen inFIG.24. InFIG.24, a delivery catheter has a nosecone752attached to a center shaft758via a tip754member. An endograft filling structure756is positioned coaxially over the center shaft758. Also coaxial to the center shaft758and proximal to the filling structure756is a sliding shaft764which can slide axially along the center shaft758. Attached distally to the sliding shaft764is an expandable member760, here a balloon, which has a stent-like scaffolding762crimped thereover. Coaxial to both shafts758,764is an outer sheath766which has an inner diameter large enough to contain both shafts758,764, the balloon760, scaffolding762and filling structure756. A pullwire768runs substantially parallel to the longitudinal axis of the shafts758,764, outside of the balloon760and scaffolding762and through the inner diameter of the filling structure756. The pullwire768is removably coupled to the filling structure756at two or more positions. In use, the outer sheath766is retracted to expose the filling structure756. The balloon760and scaffolding762are advanced over the center shaft758by advancing the sliding shaft764, through the inner diameter of the filling structure756until the balloon760and scaffolding762are axially aligned with the filling structure756. The balloon760may then be inflated, radially expanding the scaffolding762within the filling structure756. The filling structure756may then be filled with a hardenable material and the pullwire768is retracted to release the filling structure756from the shaft758and the delivery catheter may then be removed from the patient.

Many of the filling structure embodiments include a filling tube.FIG.41Aillustrates an embodiment where a single lumen filling tube4106may extend from the filling structure4102proximally so that the filling structure may be filled with a hardenable medium by a physician using a syringe, pump or other filling device. Once the filling structure is filled with hardenable medium4104, the filling tube4106may be retracted and pulled away from the filling structure4102. In some circumstances, the hardened filling medium4104may form a plug or tail4108that extends outside of the filling structure4102. This is undesirable since the tail4108could break free and migrate or it could puncture or otherwise cause trauma to adjacent tissue.FIG.41Billustrates the remaining tail4108after the filling tube4106has been released from the filling structure4102. One embodiment that minimizes or eliminates this challenge is seen inFIG.42. InFIG.42, the distal portion of the filling tube4202has a distal port4206and a plurality of side ports4204for delivering the hardenable medium to the filling structure. Additionally, the distal end of the filling tube4202has a tapered and rounded tip which reduces the diameter of the plug once hardened, creating a break point when the plug is removed.FIG.43illustrates retraction of the filling tube away from the filling structure4208after hardening of the filling medium4210. Because the filling medium is provided by multiple ports, several smaller plugs4212result and because of their smaller size, they easily break away from the filling material4210in the filling structure4208without leaving sharp protrusions. The polymer plugs remain inside the fill tube and break at the ports, instead of leaving a protruding tail. Additionally, having multiple ports4204is advantageous since the filling structure4208could be drawn into the lumen and block the distal portion4206during draining of the filling structure which can involve the use of a vacuum. The additional ports4204allow filling medium to be removed and/or delivered even if the distal port4206is blocked.

A double filling tube may be used to avoid some of the challenges discussed above. InFIG.45Aan outer filling tube4502has an inner filling tube4504extending along its length. The distal ends of both filling tube are disposed in the filling structure4508. Filling medium4506can be delivered to the filling structure4508first, via the inner filling tube4504. The inner filling tube may be retracted from both the filling structure4508and the outer filling tube4502after filling material has been delivered4508as seen inFIG.45B. The filling structure does not always completely fill up with filling medium due to a number of reasons such as viscosity, stagnation around the filling tubes, etc. More commonly, the filling structure may not be completely filled up because the physician may not infuse an adequate volume of filling medium. Thus there may be unfilled regions4510. Additional filling medium4506may be added to the filling structure4506using the outer filling tube4502or a new inner filling tube may be advanced through the outer filling tube4502. This allows the unfilled regions4510to be more completely filled as seen inFIG.45C.

The filling tubes may have many geometries. They may be round, rectangular or other configurations. Generally, it is preferred that the filling tubes have a low profile in order to maintain a low delivery diameter of the entire system. For example, inFIG.46Athe filling tube4608has a width greater than its height. This allows the filling tube to more easily fit in the annular space between the inner surface of a filling structure or outer sheath4610and the endoframe4604which mounted over a balloon4606on a delivery catheter4602.FIG.46Billustrates nesting of an inner filling tube4614in an outer filling tube3612with an optional wire mandrel or stylet4616which may be used to prevent kinking of the filling tubes. In some embodiments, a filling tube4614amay have a separate lumen4618for a stiffening mandrel.FIG.47Aillustrates an exemplary embodiment of a delivery system where the filling structure4702is axially separated from the endoframe4712and a sheath4704covers both during delivery. The endoframe4712is mounted over a balloon4710coupled to a catheter shaft4708.FIG.47Billustrates a cross section ofFIG.47Ataken along the line B-B and highlights the low profile filling tube4706in the annular space between the sheath4704and the endoframe4712. Once the sheath4704is retracted and the endoframe is advanced into the filling structure4702, pressure in the filling tube4706will force open the filling tube4706and permit greater fluid flow.

It can be challenging to maintain an airtight seal between the filling structure and the removable filling tube. Additionally, when the filling medium hardens, it can be challenging to separate the filling tube from the filling structure after in situ curing.FIGS.39A-39Cillustrate one embodiment that facilitates separation of the filling tube from the filling structure while maintaining the required airtight seal. InFIG.39Aa filling tab3904is attached to filling structure3902. The filling tab3904may be the same material as the filling structure3902or a different material. The filling tab may be welded, bonded, integral with, or otherwise attached to the filling structure. Filling tab3904has a perforation3906in it to allow for easy separation. Filling tube3908runs through filling tab3904. A duck bill valve (not illustrated) or other one-way valve may also be incorporated into the fill tab to prevent filling medium leakage. After the filling structure3902has been filled and hardened, filling tube3908is pulled away from the filling structure3902. The perforation3906allows the fill tab to easily tear away from the filling structure as seen inFIG.39Band then the fill tube is removed from the filling structure, leaving only a small portion of filling tab3904connected to the filling structure3902, as illustrated inFIG.39C. In some situations, it may be advantageous to provide some slack in the fill tab. For example, when the filling structure is coupled with the fill tube3908using a tether4006, lockwire4004, constrictor knot4008, tether loop4010(such as described above), the fill tab may be corrugated4002or additional material may be bunched together to allow expansion. The corrugation4002provides some slack in the fill tab3904to prevent unwanted detachment of the fill tube3904at the perforation3906when the fill tube3908is moved relative to the filling structure3902. Once the lockwire4004is removed from the tether4006, the tether4006is de-coupled from the tether loop4010and then the fill tab3904may be separated at the perforation3906.

Various modifications of the protocols described above will be within the scope of the present invention. For example, while some of the scaffolds have been shown as being delivered at the same time as deployment of the filling structure(s), it will also be possible to deliver the scaffolds after deployment of the filling structures. The scaffolds could be delivered on the same or different delivery catheter(s) used to deliver and/or shape the filling structures. The scaffolds could then be expanded before, during or after filling the filling structure.

Pressure monitoring can also be performed at various stages of the aneurysm repair procedure to help control the filling process of the filling structure. The monitoring of pressures serves to reduce the risk of dissection, rupture or damage to the aneurysm from over-pressurization and also can be used to determine an endpoint for filling. Monitoring can be done before, during or after filling and hardening of the filling structure with filling medium. Specific pressures which can be monitored include the pressure within the internal space of the filling structure as well as the pressure in the space between the external walls of the filling structure and the inner wall of the aneurysm. A composite measurement can also be made combining pressures such as those measured within the interior space of the filling structure, together with that in the space between the external walls of the structure and the aneurysm wall or other space at the aneurysm site and an external delivery pressure used by a fluid delivery device, such as a pump or syringe, to deliver the filling medium. Control decisions can be made using any one of these pressure measurements or a combination thereof. U.S. patent application Ser. No. 11/482,503 discloses a number of pressure measuring embodiments, the entire contents of which are incorporated herein by reference.

For example, inFIG.48A, an endoframe4802and filling structure4808are positioned in the aneurysm AAA. After preliminary expansion of the endoframe4802and filling of the filling structure4803with saline or other fluid, contrast media may be injected into the aneurysm and observed under fluoroscopy. If a leak is observed4806around the filling structure, the physician may add additional saline or fluid to the filling structure until the leak is no longer observed as illustrated inFIG.48B. The saline may then be removed from the filling structure. The volume of filling medium and pressure used to obtain this result are recorded and then used when the filling structure is filled with the hardenable filling medium. An exemplary embodiment of a delivery system capable of treating the aneurysm and providing the contrast media to the aneurysm is illustrated inFIG.49. InFIG.49, a filling structure4906having a filling tube4914is mounted over an endoframe4914which in turn is disposed over a balloon4916coupled with the delivery catheter shaft4918. A wire4910is coupled with a nosecone4908on the distal end of the delivery catheter4918. The wire4910is used to guide an angiography catheter, here a single lumen tube4912around the filling structure4906. During delivery to the aneurysm, the entire system is housed in a delivery sheath4902. While disposed in the sheath, the angiography catheter4912is proximal to the filling structure4906in order to keep profile to a minimum. Once near the device has been advanced to the aneurysm, the sheath4902may be retracted proximally thereby exposing the angiography catheter and filling structure. The angiography catheter4912may be advanced distally over the wire4910so that contrast media may be delivered upstream of the filling structure or between the aneurysm wall and the filling structure.

Similar to the filling tube, the angiography catheter should also have a low profile but its lumen should also have as large a cross-sectional area in order to allow easy, low pressure delivery of contrast media at very high flow rates, 500-1,000 cc/minute.FIG.50Aillustrates one possible embodiment for an angiography catheter. InFIG.50A, the angiography catheter5010has a flat, crescent shaped profile that lays flat and can fit in the annular space between the scaffold5006and the filling structure5008. The scaffold5006is carried by a balloon mounted near a distal end of the delivery catheter5002.FIG.50Billustrates another embodiment where the delivery catheter5002includes a guidewire lumen. The lumen is large enough to accommodate a guidewire GW and still allow delivery of contrast media. In some embodiments, the distal end of the catheter5002may include a nosecone5012having side ports5014that allow the contrast media to exit laterally, as well as the distal port5016.

In an exemplary method of deploying a filling structure and scaffolding, pressure monitoring may be utilized in the following way. After two filling structures have been delivered to the treatment site, both scaffolds are radially expanded to help create a lumen for blood flow through the filling structure across the aneurysm. Using data from a patient's computerized tomography (CT) scans, a fill volume of the aneurysm treatment site may be estimated and then divided by two, half for each of the two filling structures. This represents the baseline filling volume for each filling structure and is the minimum volume of filling material to be injected into each of the filling structures. Syringes or other injection devices coupled with a pressure gage may be used to optionally pre-fill each filling structure with contrast material using the baseline volume and the resulting baseline fill pressure may be noted. This allows unfurling of the filling structure and provides a preliminary assessment of how the expanded filling structures fit into the aneurismal space. Once this is accomplished, the contrast material is removed from the filling structures. Again using the patient CT data, a functional fill volume may be determined. This volume is a percentage of the aneurysm volume obtained from the CT data, or it may be a predetermined number and is the volume of filling material that effectively seals and excludes the aneurysm. Functional fill pressure will be the pressure at which the functional fill volume is attained. A polymer fill dispenser may then be used to fill each filling structure with the functional fill volume and the functional fill pressure is noted. While holding the functional fill volume and pressure, the filling structure may be observed under fluoroscopy to check for proper positioning, filling and the absence of leakage across the aneurysm. If leaks are observed, additional polymer may be added to the filling structures until the leaks are prevented or minimized. Excessive additional polymer should not be added to the filling structure in order to avoid exceeding a safe fill volume or safe fill pressure. Once the physician is satisfied with the filling and positioning of the filling structures, stopcocks to the filling structures may be closed to allow the polymer to harden and then the delivery devices may be removed from the patient.

FIGS.13A-13Dillustrate an exemplary method of directly monitoring pressure in the filling structure to help ensure that it is properly inflated relative to the aneurysm. InFIG.13A, a filling structure475is placed in the aneurysm A and scaffolding478provides support to the lumen created by filling structure475so that blood may flow from above the aneurysm into the iliac arteries IA. A syringe482containing a filling material such as polyethylene glycol (PEG) is fluidly coupled to the filling structure475via fluid line480. Filling pressure may be monitored in a number of ways including using a pressure gage484coupled to syringe482, a graphical pressure monitor486or a blood pressure cuff488. InFIG.13B, as syringe482is actuated, the pressure will spike and the PEG will be injected into the filling structure475. A pressure relief valve may be used to eliminate or reduce the spiking or electronic filtering may be used to remove the unwanted spike. Due to the viscosity of the PEG, as the polymer is being injected, the pressure will rise in the syringe482as measured by gage484relative to the pressure in the filling structure475as measured by gage492and also relative to the blood pressure as indicated by gage490. This pressure will rise until high enough to move the PEG through the fluid line480into the filling structure475against the pressure of the blood490. During filling, filling pressure484measured at the syringe482by gage484is equivalent to blood pressure measured at gage490and within filling structure492, and this is illustrated inFIG.13C. As the filling structure475fills and begins to expand into engagement with the aneurysm wall A, filling pressure measured by gage484will increase again. This time syringe pressure will also match pressure in the filling structure492, both of which will be greater than the blood pressure490, as seen inFIG.13D.

In addition to actual pressure monitoring by gages and graphical displays, etc., other pressure indicators may also be used to facilitate determining the filling status of the filling structure.FIGS.14A-14Cshow an exemplary embodiment employing a relief valve. InFIG.14A, a filling device502is used to fill filling structure506via fluid line504. As filling device502is actuated, fluid will be delivered to the filling structure506. Initially, there will be a pressure spike at the filling device502end of the system and because of this spike, the higher pressure drives the fluid filling medium into the filling structure506. The pressure spike also makes it challenging to use an over-pressure relief valve to prevent over pressurizing the filling structure. However, a relief valve may be located closer to the filling structure end thereby reducing the potential for unintentional bleeding of the system due to pressure spikes. InFIG.14B, a relief valve508is coupled to filling structure506. The relief valve is preset to a certain pressure such that beyond the preset pressure, any additional filling material will bleed out of the filling structure. While the relief valve may be adjacent the filling structure, preferably the filling material will be vented toward the proximal end (handle end) of the catheter, outside the body. This keeps potentially dangerous fluids or other filling material from being introduced into the body. In another embodiment seen inFIG.14C, when fluid bleeds out of relief valve508it fills a reservoir512which may be disposed either in or alongside catheter shaft510. As reservoir512fills with filling medium, it is observed under fluoroscopy or other imaging modalities and when filled, the operator knows to stop filling the filling structure506.

While the use of a pressure relief valve such as described with respect toFIGS.14A-14Ccan be advantageous, it also can present challenges. For example, inFIG.25A, a pressure relief valve804is placed in between a filling device802and the filling structure808with pressure gages806,810positioned to monitor pressure at the pressure relief valve804and at the filling structure808. Once the filling device802is actuated, pressure in the system will increase significantly which can trip the relief valve804into venting the excess pressure as seen inFIG.25Bbefore the filling structure is pressurized as seen in gage810. Thus, it will be very difficult to fill the filling structure808since most of the filling material will be vented out of relief valve804.FIGS.26A-26Cillustrate a potential solution for this challenge. InFIG.26A, a four-way, 3 port stopcock812is placed in between the filling device802and the filling structure808. Prior to actuating the filling device802, stopcock804is adjusted so that flow is turned off to the pressure relief valve804. Then, filling device802may be actuated and stopcock804may be adjusted to turn flow on in all directions. By turning the stopcock804off during actuation of filling device802, the relief valve will not be exposed to pressure spikes, thereby preventing unwanted venting.FIG.26Ashows the stopcock adjusted to turn flow off to the pressure relief valve804.FIG.26Bshows actuation of filling device802with the stopcock812still adjusted to stop flow to pressure relief valve804.FIG.26Cshows stopcock812adjusted to allow flow in all directions. Pressure gages806,810and814show relative pressure at various positions between filling device802and filling structure808.

Some embodiments do not utilize a pressure relief valve and therefore other ways of masking the pressure line from pressure spikes are also desirable. For example, when an electronic pressure transducer is used, a low pass filter may be used to eliminate the pressure spike observed during actuation of the filling device. Additionally, electronic recording devices may be set to calculate and display the average pressure over a longer period of time (e.g. sample pressure over 20 seconds rather than 2 seconds), or sampling frequency may be reduced. This will effectively eliminate the pressure spike or “mask” it out and the resulting pressure display is a value that more closely indicates pressure of the filling structure. An exemplary embodiment of a pressure gage that masks pressure spikes is illustrated inFIGS.51A-51B. InFIG.51A, pressure measuring device5104includes an internal flexible membrane5106such that when high pressure fluid is delivered from a source such as syringe5102, the membrane5106will compress and absorb some of the pressure, thereby masking any spikes. Once the membrane5106is pressed against the housing5108, it cannot deform any further and thus higher pressures will not be transmitted to the gage as seen inFIG.51B. One advantage of this type of pressure gage is that there are no static areas during pressurization and thus the hardenable filling medium cannot pool and obstruct flow.

FIGS.15A-15Billustrate still another visual indicator that may be used to control filling of the filling structure. InFIG.15A, a filling device502is fluidly coupled to filling structure506via fluid line504. A mechanical pressure indicator514is coupled with filling structure506. The mechanical pressure indicator514has two positions, a first closed position as seen inFIG.15Aand a second open position see inFIG.15B. The indicator springs open from the closed to opened position at a predetermined pressure value. The indicator is radiopaque and thus may be seen under fluoroscopy. Thus, when the indicator pops out, the operator knows that the filling structure506has reached a certain pressure and/or volume.

Placing a fluid filled balloon tipped catheter in the space between the filling structure and the aneurysm wall allows the pressure exerted by the filling structure against the aneurysm wall to be measured, and this is illustrated inFIGS.16A-16B. InFIG.16A, a partially filled, compliant balloon tipped catheter524is placed between an outer wall of filling structure520and an inner wall of the aneurysm A. The balloon catheter524may be deployed separately from or together with the filling structure deployment catheter. The balloon524may be filled with saline, carbon dioxide or like fluids. The catheter524is fluidly coupled with a pressure monitor such as gage522via a fluid line526. At neutral fill volumes, the pressure of the blood is transmitted through the balloon524, along fluid line526to pressure monitoring device522, here a pressure gage. As the filling structure520is filled with a hardenable material, it will begin to press the balloon524against the aneurysm wall, squeezing it and thus exerting a higher pressure which is transmitted along fluid line526to pressure gage522, as seen inFIG.16B. Thus, an operator may continue to fill the filling structure520until gage522indicates a desired pressure, thereby demonstrating adequate contact between the filling structure520and aneurysm wall.

In addition to monitoring pressure of a balloon524placed between the filling structure and the aneurysm wall, other pressure indicators may be used to determine when to stop filling the filling structure.FIG.17Ashows how inwardly directed pressures exerted by an expanding filling structure and an aneurysm wall are directed against a balloon546coupled to pressure gage544via fluid line542. This is similar to the embodiment previously discussed inFIGS.16A-16B. However, inFIGS.17B-17C, the pressure gage544is substituted with a spring loaded pressure indicator544. Balloon546may be partially filled and preferably has a flat section that may be placed in the space between an outer wall of a filling structure and an inner wall of the aneurysm and is fabricated from a compliant material in order to provide accurate pressure feedback. As the filling structure expands and begins to compress the balloon546against the aneurysm wall, balloon546is compressed. The pressure transmitted by fluid line542to spring loaded pressure indicator544increases. However, the spring mechanism in indicator544resists the force until a predetermined value is reached. InFIG.17C, once the predetermined value is exceeded, the spring collapses and a pin pops out of the indicator housing, alerting the user that the filling structure has been filled or that a desired pressure has been obtained. Different springs may be used in order to adjust the indicator to different pressure set points. In alternative embodiments, other compression mechanisms other than springs may be used.

The balloon546and pressure indicator544may be integrated with a filling mechanism or the two may be separate from one another.FIGS.18A-18Billustrate a combined filling mechanism with pressure indicator that serves as a lockout mechanism to prevent overfilling of the filling structure. InFIG.18A, a gun-like filling device552comprises a handle554for actuating the filling device552. As handle554is actuated by squeezing, filling material is discharged from a reservoir through a filling tube into the filling structure. A rack556having teeth is coupled with handle554to provide an operator with tactile feedback so that the operator knows how far handle554has been actuated. A locking mechanism560similar to the pressure indicator described above with respect toFIGS.17A-17Cis also coupled with filling device552. In this embodiment, when pressure from fluid line558coupled to the filling structure or a balloon catheter exceeds a predetermined value, plunger562springs out of the locking mechanism560and engages one of the teeth on rack556, thereby preventing further actuation of handle554. Thus, filling mechanism552may be used to fill the filling structure but without overfilling it.

Instead of a separate balloon catheter placed between the filling structure and aneurysm wall, the filling structure may include a separate compartment that acts like the balloon catheter previously described inFIGS.16A-16B.FIG.19Aillustrates a filling structure576having a separate compliant compartment578. Compartment578may be pre-filled with a fluid such as saline or carbon dioxide. As filling structure576is filled and expands into the aneurysm wall, compartment578will be compressed and pressure therein will increase. Pressure in compartment578may be monitored via fluid line580by any number of methods including using a gage, a display or the like. This embodiment saves the operator from having to deliver a balloon catheter like that ofFIGS.16A-16Bto the site of the aneurysm.FIG.19Billustrates a side view of the embodiment inFIG.19A.

FIG.19Cillustrates how the filling structure576may include a compliant balloon-like member578for monitoring pressure between the filling structure and the aneurysm wall. In this embodiment, the balloon-like member578includes upper and lower arms582that circumferentially extend around all or a portion of the filling structure576. The arms582allow contact between different parts of the filling structure to be monitored thereby preventing over inflation in one region and underinflation in another region. A fluid line580allows the balloon-like member578to be coupled with a pressure monitoring device.FIG.19Dillustrates still another embodiment of a filling structure having multiple separate compartments584located at several different points around filling structure576. Similar to the embodiment ofFIG.19C, having multiple compartments allow filling of the filling structure to be assessed at several locations to ensure uniformity of filling. Each compartment may monitor pressure independently of the other compartments or they may be fluidly coupled together.

The scaffolding itself may also be used to indicate the filling status of the filling structure. InFIG.20A, a filling structure is disposed over scaffold604. Scaffold604has regions606which are designed to collapse at a lower radial pressure than the rest of the scaffold. Thus, when filling structure602is filled, it will exert a force against scaffold604. The weakened regions606collapse inwardly slightly, without substantially occluding the lumen for blood flow, thereby forming a series of peaks and valleys which are visible under fluoroscopy. This is illustrated inFIG.20B. An operator may therefore use this to monitor the extent of filling in the filling structure602.

In still another embodiment, the balloon used to radially expand the scaffolding may also be used to monitor pressure. InFIG.21, a delivery catheter610comprises an expandable balloon618disposed on a distal end of the catheter shaft and a scaffolding614is disposed thereover. Once the filling structure616is advanced into the aneurysm it may be filled. Balloon618is partially expanded into engagement with the filling structure616. As the filling structure enlarges, it begins to compress the balloon614. Catheter610transmits the pressure from balloon616to a pressure gage612so that the operator may monitor filling pressure. Thus, the operator may stop filling the filling structure when a predetermined pressure value is obtained. The scaffolding614may then be fully expanded either before, during or after filling the filling structure. The balloon618is then deflated and the delivery catheter610is removed from the aneurysm.

Other embodiments may control filling of the filling structures by using either a balloon on the delivery catheter or the filling structures themselves. For example, inFIGS.27A-27B, two filling structures852,854are positioned in the aneurysm AAA and partially filled with a filling device862to a predetermined volume or pressure. Balloons856,858on a delivery catheter are inflated using an inflation device860. As the balloons expand, the partially filled filling structures852,854are pressed against the aneurysm walls, filling the aneurismal space and excess fluid is then forced out of the filling structures852,854via a relief valve868seen inFIG.27B. Scaffolds864,866help maintain the lumen after the balloons856,858are deflated.

FIGS.28A-28Billustrate another embodiment where the filling structures themselves are used to help control their filling status. InFIG.28A, two filling structures852,854are positioned in the aneurysm AAA. A first filling structure852is at least partially filled. InFIG.28B, the second filling structure854is filled so that it compresses filling structure852. As filling structure852is compressed, excess fluid is vented from filling structure852via a pressure relief valve868. This process is continued until the filling structures are essentially symmetrical with one another as may be observed under fluoroscopy.

While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. The various features of the embodiments disclosed herein may be combined or substituted with one another. Therefore, the above description should not be taken as limiting in scope of the invention which is defined by the appended claims.