US20110130820A1 - Modular endograft devices and associated systems and methods - Google Patents

Abstract

Modular endograft devices and associated systems and methods are disclosed herein. In several embodiments, an endograft system can include a first endograft device and a second endograft device that each include an integrated frame, a cover and a lumen within the cover. Each endograft device further includes a superior portion and an inferior portion. The superior portion can have a convexly curved outer wall and a septal wall. The first and second endograft devices can be configured to extend into a low-profile configuration with a first cross-sectional dimension and a first length and self-expand into an expanded configuration with a second cross-sectional dimension greater than the first cross-sectional dimension and a second length less than the first length. In the expanded configuration, the septal walls can press against each other and form a septum between the lumens of the first and second endograft devices.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• The present application claims priority to each of the following U.S. Provisional Applications:
• (A) U.S. Provisional Application No. 61/265,713, filed on Dec. 1, 2009, entitled “IMPROVED SYSTEMS AND METHODS FOR MODULAR ABDOMINAL AORTIC ANEURYSM GRAFT;” and
• (B) U.S. Provisional Application No. 61/293,581, filed Jan. 11, 2010, entitled “IMPROVED SYSTEMS AND METHODS FOR MODULAR ABDOMINAL AORTIC ANEURYSM GRAFT.”
• All of the foregoing applications are incorporated herein by reference in their entireties.
TECHNICAL FIELD
• The present technology generally relates to endograft devices and methods for percutaneous endovascular delivery of the endograft devices across aneurysms. In particular, several embodiments are directed toward a modular bi-luminal endograft device with independently positioned components for endovascular aneurysm repair.
BACKGROUND
• An aneurysm is a dilation of a blood vessel at least 1.5 times above its normal diameter. The dilated vessel can form a bulge known as an aneurysmal sac that can weaken vessel walls and eventually rupture. Aneurysms are most common in the arteries at the base of the brain (i.e., the Circle of Willis) and in the largest artery in the human body, the aorta. The abdominal aorta, spanning from the diaphragm to the aortoiliac bifurcation, is the most common site for aortic aneurysms. The frequency of abdominal aortic aneurysms (“AAAs”) results at least in part from decreased levels of elastins in the arterial walls of the abdominal aorta and increased pressure due to limited transverse blood flow.
• Aneurysms are often repaired using open surgical procedures. Surgical methods for repairing AAAs, for example, require opening the abdominal region from the breast bone to the pelvic bone, clamping the aorta to control bleeding, dissecting the aorta to remove the aneurysmal section, and attaching a prosthetic graft to replace the diseased artery. The risks related to general anesthesia, bleeding, and infection in these types of open surgical repairs result in a high possibility of operative mortality. Thus, surgical repair is not a viable option for many patients. Moreover, the recovery process is extensive for the patients fit for surgical repair. An open surgical repair of an AAA generally requires seven days of post-operational hospitalization and, for uncomplicated operations, at least six to eight weeks of recovery time. Thus, it is a highly invasive and expensive procedure.
• Minimally invasive surgical techniques that implant prosthetic grafts across aneurysmal regions of the aorta have been developed as an alternative or improvement to open surgery. Endovascular aortic repairs (“EVAR”), for example, generally require accessing an artery (e.g., the femoral artery) percutaneously or through surgical cut down, introducing guidewires into the artery, loading an endograft device into a catheter, and inserting the loaded catheter in the artery. With the aid of imaging systems (e.g., X-rays), the endograft device can be guided through the arteries and deployed from a distal opening of the catheter at a position superior to the aneurysm. From there, the endograft device can be deployed across the aneurysm such that blood flows through the endograft device and bypasses the aneurysm.
• EVAR devices should be implanted at a precise location across the aneurysmal region and securely fixed to the vessel wall because improper placement, migration, and/or projection of the endograft device into branching vessels may interfere with the blood flow to nearby physiological structures. For example, to avoid impairing renal functions, the endograft device should not inhibit blood flow to the renal arteries. In addition to the variations in the vasculature between patients, the characteristics of the aneurysms themselves can also pose challenges because of the anatomical variations and the different structural features of individual aneurysms. For example, the vascular bifurcation at the iliac arteries and the angulation of aneurysmal sacs are both known to pose challenges to methods and devices for treating AAAs. Conventional systems address these challenges by having many different EVAR devices with different sizes and shapes.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1A is a partial cut-away, isometric view of a modular endograft system configured in accordance with an embodiment of the technology.
• FIG. 1B is an isometric view of the modular endograft system ofFIG. 1A configured in accordance with an embodiment of the technology.
• FIGS. 2A-C are cross-sectional top views of superior portions for endograft devices shaped in accordance with embodiments of the technology.
• FIGS. 2D and 2E are cross-sectional top views of the superior portion ofFIG. 2B being mated with a complementary superior portion in accordance with an embodiment of the technology.
• FIGS. 3A and 3B are isometric views of endograft devices configured in accordance with embodiments of the technology.
• FIGS. 4A and 4B are side views of an integrated frame in an expanded configuration and in a low-profile configuration, respectively, in accordance with an embodiment of the technology.
• FIGS. 5A-C are side views of a cover being extended from an expanded configuration to a low-profile configuration in accordance with an embodiment of the technology.
• FIGS. 6A and 6B are cross-sectional views of an endograft device in a low-profile configuration and in an expanded configuration, respectively, in accordance with embodiments of the technology.
• FIGS. 7A and 7B are isometric views of endograft devices configured in accordance with other embodiments of the technology.
• FIGS. 8A and 8B are isometric views of endograft devices configured in accordance with further embodiments of the technology.
• FIGS. 9A and 9B are schematic views of a two-part modular endograft system being deployed across an aneurysm in accordance with an embodiment of the technology.
• FIGS. 10A and 10B are isometric views of modular endograft systems configured in accordance with additional embodiments of the technology.
• FIGS. 11A and 11B are schematic views of the modular endograft system ofFIG. 10A and the modular endograft system ofFIG. 10B, respectively, deployed across aneurysms in accordance with other embodiments of the technology.
• FIG. 12 is a schematic view of the modular endograft system ofFIG. 9B deployed across an aneurysm in accordance with a further embodiment of the technology.
• FIGS. 13A-C are schematic views of a four-part modular endograft system being deployed across an aneurysm in accordance with an embodiment of the technology.
• FIGS. 14A and 14B are isometric views of a modular endograft system configured in accordance with an additional embodiment of the technology.
• FIGS. 15A and 15B are schematic views of a three-part modular endograft system being deployed across an aneurysm in accordance with an embodiment of the technology.
• FIG. 16 is a schematic view of a five-part modular endograft system being deployed across an aneurysm in accordance with an embodiment of the technology.
• FIGS. 17A-E are views of coating layers being applied to an integrated frame in accordance with an embodiment of the technology.
DETAILED DESCRIPTION
• Specific details of several embodiments of the technology are described below with reference toFIGS. 1A-17E. Although many of the embodiments are described below with respect to devices that at least partially repair abdominal aortic aneurysms (“AAAs”), other applications and other embodiments are within the scope of the technology. For example, the technology can be used to repair aneurysms in other portions of the vasculature. Additionally, several other embodiments of the technology can have different configurations, components, or procedures than those described in this section. A person of ordinary skill in the art, therefore, will accordingly understand that the technology may have other embodiments with additional elements, or the technology may have other embodiments without several of the features shown and described below with reference toFIGS. 1A-17E.
• With regard the use of “superior” and “inferior” within this application, inferior generally refers being situated below or directed downward, and superior generally refers to being situated above or directed upward.
• With regard to the use of “expansion” and “constriction” within this application, expansion refers to a radial increase in a cross-sectional dimension of a device or component, and constriction refers to a radial decrease in the cross-sectional dimension of the device or component. For example,FIG. 4A shows anintegrated frame104 in an expanded configuration, andFIG. 4B shows theintegrated frame104 in a constricted configuration.
• With regard to the use of “contraction” and “extension” within this application, contraction refers to a longitudinal decrease in the length of a device or component, and extension refers to a longitudinal increase in the length of the device or component. For example,FIG. 5A shows acover106 in a contracted configuration, andFIG. 5C shows thecover106 in an extended configuration.
• With regard to the terms “distal” and “proximal” within this application, the terms can reference a relative position of the portions of an implantable device and/or a delivery device with reference to an operator. Proximal refers to a position closer to the operator of the device, and distal refers to a position that is more distant from the operator of the device.
• 1. Endograft System Structures
• 1.1 Selected Endograft Devices
• FIGS. 1A and 1B are isometric views of a modular endograft system100 (“system100”) in accordance with an embodiment of the technology. Thesystem100 can include separate endograft devices102 (identified individually as afirst endograft device102aand asecond endograft device102b) that can be coupled, mated, or otherwise substantially sealed together in situ. Eachendograft device102, for example, can include an integrated frame104 (“frame104”) and a substantially impermeable cover106 (“cover106”) extending over at least a portion of theframe104. Theframe104 and thecover106 of anindividual endograft device102 can form adiscrete lumen116 through which blood can flow to bypass an aneurysm. In operation, theendograft devices102 are generally delivered separately and positioned independently across the aneurysm.
• As shown inFIGS. 1A and 1B, eachendograft device102 includes asuperior portion108 and aninferior portion110. Thesuperior portion108 can include a convexly curvedouter wall112 and aseptal wall114. As shown inFIG. 1A, theseptal wall114 can be substantially flat such that thesuperior portion108 forms a “D” shape at a superior portion of thelumen116. In other embodiments, theseptal wall114 can be convexly curved with a larger radius of curvature than theouter wall112 such that thesuperior portion108 forms a complex ellipsoid having another D-shaped cross-section at the superior portion of thelumen116. In further embodiments, thesuperior portion108 can have asymmetrical shapes or other suitable cross-sectional configurations that can mate with each other in the septal region and mate with an arterial wall around the periphery of theouter wall112. Theinferior portion110 can have a circular cross-sectional shape as illustrated inFIG. 1A, or theinferior portion110 can have an elliptical shape, a rectangular shape, an asymmetrical shape, and/or another suitable cross-sectional shape for an inferior portion of thelumen116.
• Thesuperior portions108 of theendograft devices102 are mated together and at least substantially sealed along theseptal walls114 within the aorta above the aneurysm. In some embodiments, thesuperior portion108 can be approximately 2-4 cm in length to adequately fix theouter walls112 to the arterial walls such that they are at least substantially sealed together. In other embodiments, thesuperior portion108 can be longer or shorter. In one embodiment in accordance with the technology, theinferior portions110 can extend through an inferior portion of the aneurysm and into corresponding iliac arteries to bypass the aneurysm. In another embodiment, one or bothinferior portions110 can terminate within the aneurysm to form what is known to those skilled in the art as a “gate.” As described in further detail below, limbs (not shown) can be attached to the proximal ends of theinferior portions110 and extended into the iliac arteries to bypass the aneurysm.
• In the embodiment shown inFIGS. 1A and 1B, theframes104 have bare end portions118 (identified individually asfirst end portions118aandsecond end portions118b) that extend beyond thecovers106. As shown inFIGS. 1A and 1B, thefirst end portion118acan extend distally from the superior terminus of thecover106, and thesecond end portion118bcan extend proximally from the inferior terminus of thecover106. In some embodiments, the end portions118 can be trumpeted or flared to interface with the arterial walls of the aorta and/or the iliac arteries. This can promote cell ingrowth that strengthens the seal between theendograft devices102 and the adjacent arteries.
• The end portions118 can also increase the available structure for securing theendograft device102 to the artery and increase the surface area of thecovers106 for sealably fixing theendograft devices102 to arterial walls. This decreases the precision necessary to position theendograft devices102 and increases the reliability of the implantedsystem100. For example, a short infrarenal aortic neck (e.g., less than 2 cm) generally requires precise placement of theendograft devices102 to preserve blood flow to the renal arteries while still providing enough surface area for theendograft devices102 to be properly affixed with the aorta. In the embodiment shown inFIGS. 1A and 1B, however, thefirst end portions118acan be placed at the entrance of the renal arteries to allow lateral blood flow into the renal arteries and provide a larger structure for fixing theendograft devices102 to the arterial wall and a larger sealing area with the arterial wall. The end portions118 can also provide accessible sites for recapture (e.g., by guidewires, bead and collet, etc.) that enhance the accuracy of positioning theendograft devices102 across the aneurysm.
• During deployment of thesystem100, eachendograft device102 can be delivered independently to an aneurysmal region in a low-profile configuration. The low-profile configuration has a first cross-sectional dimension and a first length that can facilitate percutaneous endovascular delivery of thesystem100. Because eachdevice102 extends around only a portion of the vessel periphery, theindividual endograft devices102 can be constricted (i.e., radially collapsed) to a smaller diameter than conventional AAA devices with a single superior portion that extends around the complete periphery of the vessel wall. In some embodiments, for example, each of theendograft devices102 can have a diameter of 25 mm in the expanded configuration, and can be constricted to a diameter of 4 mm in the low-profile configuration to be percutaneously deployed across the aneurysm through a 12 F catheter. Additionally, as described in more detail below, because eachendograft device102 is delivered independently, the end portions118 and fenestrations can facilitate staggering theendograft devices102 to accommodate asymmetrical anatomies.
• At a target site in the aneurysmal region, theendograft devices102 can self-expand to an expanded configuration (e.g., shown inFIGS. 1A and 1B). The expanded configuration can have a second cross-sectional dimension greater than the first cross-sectional dimension and a second length less than the first length. In the expanded configuration shown inFIG. 1B, the septal wall114 (FIG. 1A) of thefirst endograft device102acan be forced against the opposingseptal wall114 of thesecond endograft device102b.When in situ within the aorta, the forces between the opposingseptal walls114 form aseptum120 in which the first and secondseptal walls114 are at least substantially sealed together to prevent blood from flowing between theendograft devices102 and into the aneurysm. Additionally, as shown inFIG. 1B, the texture (e.g., ribbing) on thecovers106 can mate at theseptum120 to further strengthen the seal between theseptal walls114. Similarly, the texture of thecover106 on theouter walls112 can interface with the adjacent vessel walls to strengthen the seal around the periphery of theendograft devices102.
• In operation, thesystem100 can prevent blood from collecting in a diseased aneurysmal portion of a blood vessel (e.g., the aorta, the iliac arteries, etc.). Rather, thesystem100 can direct blood into thelumens116, funnel the blood through the superior andinferior portions108 and110, and discharge the blood into healthy portions of the iliac arteries, thereby at least substantially bypassing the aneurysm. Thebifurcated system100 facilitates independent positioning of the first andsecond endograft devices102 to accommodate disparate structures and morphologies of the abdominal aorta and/or iliac arteries. For example, thefirst endograft device102acan be positioned independently in a desired location without being constrained by a desired placement of thesecond endograft device102b.Accordingly, thesystem100 can easily adapt to a variety of different anatomies and thereby provide a modular alternative to customized endograft systems.
• 1.2 Select Embodiments of Superior Portions
• FIGS. 2A-C are cross-sectional top views ofsuperior portions208 of endograft devices (e.g.,endograft devices102 shown inFIGS. 1A and 1B) shaped in accordance with embodiments of the technology. Thesuperior portions208 can have generally similar features as thesuperior portions108 shown inFIGS. 1A and 1B. For example, eachsuperior portion208 includes anouter wall212 and aseptal wall214. Theouter wall212 is generally semi-circular, but can otherwise be configured according to the shape, geometry, and/or morphology of an arterial wall. Theseptal wall214 can be shaped to mate with a complementaryseptal wall214 of another endograft device. More specifically, in the embodiment illustrated inFIG. 2A, thesuperior portion208 includes a convexly curved, substantially semi-circularouter wall212 and a substantially flatseptal wall214. Thus, thesuperior portion208 forms a “D” shape and can be part of a system (e.g., thesystem100 shown inFIGS. 1A and 1B) including a corresponding D-shaped superior portion of a mating endograft device.
• In other embodiments, both theouter wall212 and theseptal wall214 can be convexly curved such that thesuperior portion208 forms a complex ellipsoid with at least two distinct radii.FIG. 2B, for example, shows thesuperior portion208 can include a convexly curvedouter wall212 that has a first radius R1 and a convexly curvedseptal wall214 that has a second radius R2 greater than the first radius R1. In the embodiment illustrated inFIG. 2B, the second radius R2 is substantially greater than the first radius R1 such that thesuperior portion208 has a substantially D-like shape.
• Similarly, thesuperior portion208 shown inFIG. 2C includes the convexly curvedouter wall212 that has the first radius of curvature R1 and the convexly curvedseptal wall214 that has the second radius of curvature R2 greater than the first radius R1. As shown inFIG. 2C, thesuperior portion208 can further include convexly curved corner sections222 (identified individually as afirst corner section222aand asecond corner section222b). Thefirst corner section222acan have a third radius R3, and thesecond corner section222bcan have a fourth radius R4 distinct from or equivalent to the third radius R3. In the embodiment shown inFIG. 2C, the third and fourth radii R3 and R4 are substantially smaller than the first and second radii R1 and R2 such that thesuperior portion208 forms another substantially D-like shape. In other embodiments, thesuperior portion208 can include greater or smaller radii, more or less curved portions, and/or can have another shape suitable for mating and at least substantially sealing two endograft devices together within a blood vessel.
• FIGS. 2D and 2E are cross-sectional top views of thesuperior portion208 ofFIG. 2B being mated with a complementarysuperior portion208 to form a sealedseptum220 in accordance with an embodiment of the technology. More specifically,FIG. 2D shows thesuperior portions208 being pressed toward one another by a force F. The force F can derive from the self-expansion of thesuperior portions208 within the confined space of an aorta. As shown inFIG. 2D, the force F can cause thesuperior portions208 to contact one another near the center of their respective convexly curvedseptal walls214 and flatten theseptal walls214. The apposition of theseptal walls214 can generate an outward force generally tangential to theseptal walls214 that can cause a slight outward bowing B near the interface of the outer andseptal walls212 and214.
• As shown inFIG. 2E, the force F can continue to press thesuperior portions208 against one another until the convexly curvedseptal walls214 straighten to form theseptum220. The initial convexities of theseptal walls214 can induce more pressure between theseptal walls214 than straight septal walls (e.g.,FIG. 2A) and promote an even distribution of the force along theseptum220 to enhance the seal. Additionally, the outward bowing B can enhance the seal at the edges of theseptal walls214. Thesuperior portions208 shown inFIGS. 2A and 2C can be similarly joined to form the substantiallystraight septum220. For example, thesuperior portion208 shown inFIG. 2C can be pressed against a corresponding superior portion such that the relative forces between thesuperior portions208 substantially straighten theseptal walls214 and corner sections222 (e.g., approximately 60° to 90° between the outer andseptal walls112 and114) to form theseptum220. In operation, theseptum220 can be at least substantially sealed to prevent fluids (e.g., blood) from flowing between thesuperior portions208.
• 1.3 Select Embodiments of Transition Portions
• FIGS. 3A and 3B are isometric views oftransition portions324 of endograft devices configured in accordance with embodiments of the technology. Thetransition portions324 can promote laminar blood flow by gradually changing the size of thelumen116 from the wider,superior portion108 to the narrower,inferior portion110. Additionally, thetransition portions324 can be configured to reduce the downforce exerted on theendograft devices102 as blood flows through thelumen116.
• More specifically,FIG. 3A is an isometric view of theendograft device102 described above with reference toFIGS. 1A and 1B. Theendograft device102 includes thetransition portion324 positioned between thesuperior portion108 and theinferior portion110. As shown inFIG. 3A, thetransition portion324 can be tapered to gradually narrow the cross-section of thelumen116 and thereby reduce disruptions to the blood flow. Thetransition portion324 can have a length L related to the distance necessary to continue substantially laminar blood flow through thelumen116. For example, in some embodiments, the length L can be 4 cm. In other embodiments, the length L can differ due to the geometry of theendograft device102, the rheologic characteristics of the blood flow, and/or other relevant factors in decreasing turbulent blood flow. In other embodiments, thetransition portion324 can be sloped, stepped, and/or have another suitable shape that can decrease the cross-section of thelumen116 from thesuperior portion108 to theinferior portion110 without inducing turbulent blood flow.
• FIG. 3B is an isometric view of anendograft device302 in accordance with another embodiment of the technology. Theendograft device302 can include generally similar features as theendograft102 shown inFIG. 3A. However, the taperedtransition portion324 shown inFIG. 3B has a more gradual taper and a much greater length L than thetransition portion324 shown inFIG. 3A. As shown inFIG. 3B, the taperedtransition portion324 extends from thesuperior portion108 to thesecond end portion118bsuch that thetransition portion324 defines the inferior portion110 (not visible). Accordingly, the taperedtransition portion324 can steadily decrease the cross-section of thelumen116 to facilitate laminar blood flow through thelumen116. The gradual taper of thetransition portion324 may, however, cause theendograft device302 to migrate in the direction of blood flow more than the more aggressive taper of thetransition portion324 shown inFIG. 3A. Accordingly, the length L and angle of the taperedtransition portion324 can be optimized to mitigate migration of theendograft device302 without inducing undo turbulent blood flow. In other embodiments, thetransition portion324 can optimize the geometry of a different shape (e.g., stepped) to maintain laminar blood flow and mitigate migration of theendograft device302.
• 2. Endograft System Components
• 2.1 Integrated Frames
• FIGS. 4A and 4B are side views of theintegrated frame104 described with reference toFIGS. 1A and 1B in an expanded configuration (FIG. 4A) and a low-profile configuration (FIG. 4B) in accordance with an embodiment of the technology. As discussed above, theframe104 includes thesuperior portion108, theinferior portion110, and the exposed end portions118. In some embodiments, the smallest radius of theouter wall112 of eachsuperior portion108 in the expanded configuration may not be less than 10 mm (i.e., the smallest diameter of thesuperior portions108 of matedendograft devices102 is more than 20 mm).
• As shownFIGS. 4A and 4B, theframe104 can be a braided structure made from one or more continuous, interwovenwires426 that provide a continuous, integrated support longitudinally along the length of theframe104. For example, as shown inFIG. 4A, thewire426 is braided such that a first longitudinal segment L1 of theframe104 supports an adjacent second longitudinal segment L2 of theframe104. Accordingly, each area of theframe104 influences the radial expansion or contraction of an adjacent area of the frame. In some embodiments, theframe104 is woven with onewire426 that continuously crosses itself along the length of theframe104. The intersections of thewire426 may not be welded or otherwise fixed together such that they remain unbound to increase the flexibility of theframe104. In other embodiments, theframe104 includes a plurality ofwires426 that can be interwoven and/or concentrically layered to form theframe104. Theframe104, for example, can include eightwires426 in which several of thewires426 can end at intermediate points along the length of theframe104. Such a staggered, multi-wire construction prevents the wire ends from weakening theframe104 and/or from wearing on a subsequently attached cover (e.g., thecover106 shown inFIGS. 1A and 1B). The number ofwires426 can also vary at different sections along the length of theframe104. For example, in one embodiment, theinferior portion110 includesfewer wires426 than thesuperior portion108 such that the density or pitch of thewires426 does not increase atinferior portion110 and theframe104. This enables theinferior portion110 to have a small diameter in the constricted, low-profile configuration (FIG. 4B).
• As shown inFIG. 4A, thewires426 can form aloop428 at one end portion118 to reverse direction and continue weaving along the length of theframe104 toward the opposite end portion118. The optimal number ofloops428 at each end portion118 can be associated with the diameter of thewires426. Toofew loops428 can decrease the strength at the end portions118 of the contractedframe104 shown inFIG. 4A. Toomany loops428 can increase the profile of the extended frame424 shown inFIG. 4B, and can also cause difficulty attaching the cover. Awire426 with a diameter of 0.008 inch, for example, may have an optimal number of ten to twelve loops428 (five to six at each end portion118), whereas awire426 with a diameter of 0.009 inch may have an optimal number of twelve to fourteenloops428. In other embodiments, thewires426 can include more orless loops428 to optimize characteristics of theframe104. Additionally, the degree of curvature of each of theloops428 can impact the durability of thewires426. For example, tightly woundloops428 with high degrees of curvature are subject to fatigue and failure at the end portions118 because of the stress induced upon constriction. Therefore, in some embodiments, the degree of curvature of theloops428 can be the least degree of curvature permissible for the optimal number ofloops428.
• In the expanded configuration shown inFIG. 4A, thewires426 can cross at a braid angle θ selected to mitigate kinking and provide adequate extension/constriction. Lower braid angles θ can reduce or eliminate kinking of thewires426 when theframe104 is flexed or bent. For example, a braid angle θ of less than 45° allows theframe104 to bend with smaller radii of curvature without substantial reduction of its cross-sectional area along the length of theframe104. Therefore, aframe104 with a braid angle θ of less than 45° can be flexed and bent within the anatomy (e.g., the aorta) without restricting blood flow through theframe104. Additionally, lower braid angles θ can increase the outward spring force (i.e., the inherent force within theframe104 that self-expands theframe104 to the expanded configuration) and hoop strength (i.e., the radial strength of theframe104 that restricts kinking and maintains the expanded configuration) of theframe104. Therefore, braid angles θ of not more than 45° can also provide an advantageous increase in the strength and corresponding durability of theframe104.
• Lower braid angles θ, however, can also adversely affect the extension and constriction of theframe104 in the low-profile configuration shown inFIG. 4B. For example, extension and constriction can be negatively impacted at braid angles θ of less than 30°. Therefore, in some embodiments, theframe104 can include a braid angle θ between 30° and 45° that promotes kink resistance and frame strength, while also maintaining extension and constriction abilities necessary for the low-profile configuration. In other embodiments, the optimal braid angle θ can be higher or lower.
• In some embodiments in accordance with the technology, the braid angle θ can vary along the length of theframe104 to vary kink resistance, outward spring force, hoop strength, and extension properties at different portions of theframe104. For example, the braid angle θ can be higher at the superior portion108 (e.g., 40°) such that thesuperior portion108 can extend and constrict into the low-profile configuration, and the braid angle θ can be lower at the inferior portion110 (e.g., 30°) to provide kink resistance where theframe104 is most likely to bend (e.g., within the aneurysmal sac and toward the iliac arteries). The smaller braid angle θ at theinferior portion110 may not adversely affect the profile of theframe104 because theinferior portion110 need not constrict as much as thesuperior portion108 to reach the desired low-profile configuration. In other embodiments, the braid angle θ of theframe104 may vary in another way.
• Thewires426 can have a diameter sufficient to support theframe104 while still providing substantial flexibility for theframe104. The diameter of thewires426 can be selected to attain a desired cross-sectional dimension in the low-profile configuration, a desired outward spring force to self-expand to the expanded configuration, and a desired hoop strength to support theframe104 in the expanded configuration. For example, in some embodiments, thewires426 can have a diameter from approximately 0.007 inch to approximately 0.014 inch. In specific embodiments, the wires have a diameter from approximately 0.011 inch to 0.013 inch. In other embodiments, thewires426 can have a smaller diameter, a greater diameter, and/or the diameter of thewires426 can vary along the length of theframe104. For example, in one embodiment, thewires426 can have a greater diameter at thesuperior portion108 than at theinferior portion110 such that thewires426 of thesuperior portion108 have a outward spring force and greater hoop strength where the first and second endograft devices mate (e.g., at the septal walls114) and the increased density ofwires426 at theinferior portion110 does not negatively impact the flexibility of theframe104.
• Theframe104 may be constructed from a variety of resilient metallic materials, polymeric materials (e.g., polyethylenes, polypropylenes, Nylons, PTFEs, and the like), and composites of materials. For example, thewires426 can be made from biocompatible stainless steels, highly elastic metallic alloys, and biocompatible shape setting materials that exhibit shape memory properties. In some embodiments, for example, thewire426 can be made from a shape setting alloy, such as Nitinol, that has a preferred or native configuration. For example, a Nitinol structure can be deformed or constrained into a secondary configuration, but upon release from the constraint, the structure returns toward its native configuration with high fidelity. Accordingly, aframe104 made fromNitinol wires426 can reliably self-expand from the low-profile configuration the expanded configuration (i.e., its native configuration).
• For endovascular delivery of a device (e.g., theendograft devices102 shown inFIGS. 1A and 1B), theframe104 is extended to constrict theframe104 into a low-profile configuration in which theframe104 can be loaded into a delivery device. The braid angle θ of thewires426 can facilitate significant extension of theframe104 to produce a slender profile during delivery as described above, and yet the interwoven characteristic of the braid restricts over extension. This extension-constriction functionality of theframe104 allows theframe104 to have variable diameters (e.g., the diameter of thesuperior portion108 compared to the diameter of the inferior portion11) using the same number ofwires426 on each portion of theframe104 such that theframe104 has a low introduction profile (e.g., diameter) along the length of theframe104. Theframe104 can also include an optimal number ofloops428 at each end portion118 such that theloops428 do not increase the profile of theframe104 upon full extension.
• At a target site (e.g., above an aneurysm), theframe104 self-expands to the expanded configuration shown inFIG. 4A as it is removed from the delivery device. The braid angle θ can be adjusted to change the outward spring force and hoop strength of the expandedframe104 as explained above. In some circumstances, the endograft device may need to be repositioned after being partially deployed. Theframe104 is well suited for such repositioning because theloops428 and the continuous, interwovenwires426 can simplify recapture of theframe104 and allow for constriction after expansion to correctly reposition the endograft device. Additionally, portions of theframe104 can remain exposed (e.g., the end portions118) to encourage cell ingrowth for securely anchoring theframe104 to the arterial walls. Moreover, as described in more detail below, the interwovenwires426 of thebraided frame104 can provide a continuous longitudinal support along the length of theframe104 such that theframe104 can be staggered and free end portions can support themselves. Theframe104 can also facilitate attachment to other endograft devices. For example, theframe104 can interlace with another interwovenwire426 of a supra-renal endograft.
• Once deployed across the aneurysm, theframe104 can also accommodate disparate anatomies and morphologies. In several patients, the aneurysmal sac extends at an angle with respect to the neck of the aneurysm. Because theframe104 can have a braid angle θ that prevents kinking, theframe104 can bend and flex without kinking to accommodate angulated aneurysmal sacs without restricting blood flow. Additionally, the unbound, wovenwires426 give the frame104 a radial elasticity such that theframe104 mimics the changes in the shape and morphology of the aorta without hindering the interface or seal between the endograft device and the vessel wall. For example, the frame404 can constrict and expand to maintain the seal when pressure and other conditions alter the vasculature of the aorta. Moreover, the wovenwires426 inherently generate a spring force that biases theframe104 toward a substantially straight trajectory within an aneurysmal sac and thereby limits migration of the endograft device.
• In addition, the constant outward spring force and hoop strength of thebraided frame104 can be adjusted by changing the braid angle θ and/or the diameter of thewires426. This allows the formation of large diameter frames104 without a significant change in the low-profile cross-sectional dimensions. Additionally, this feature allows theframes104 to contract to a much smaller introduction profiles (e.g., diameters) compared to standard Z-frames or M-frames because the standard Z-frames and M-frames tend to require more wire and therefore larger introduction profiles to maintain a constant outward spring force and hoop strength.
• 2.2 Covers
• FIGS. 5A-C are views of a cover being extended from an expanded configuration (FIG. 5A) to a low-profile configuration (FIG. 5C) in accordance with embodiments of the technology. More specifically,FIG. 5A is a side view of thecover106 described above with reference toFIGS. 1A and 1B in the expanded configuration. Thecover106 can include a plurality ofcircumferential ribs530 such that thecover106 has an undulating profile. As shown inFIG. 5A, theindividual ribs530 can have a substantially triangular shape with an apex533. In other embodiments, theindividual ribs530 have rounded edges, rectangular edges, and/or other suitable textures that can extend and contract.
• Theribs530 of one cover can mate with opposingribs530 of an opposing cover and interface with vessel walls to enhance the seal and fixation between endograft devices in an endograft system (e.g., theendograft devices102 of theendograft system100 shown inFIGS. 1A and 1B) and between the endograft devices and the arterial walls. For example, theapices533 of theribs530 at theseptal wall114 of thesuperior portion108 of one endograft device can interface or mate with the troughs of thecorresponding ribs530 on a cover of an opposing endograft device. Additionally, theribs530 at theouter wall112 can contact the arterial walls in a manner that at least substantially seals them together. Theribs530 can also allow thecover106 to flex and bend without wrinkling in situ. In some embodiments, theribs530 can be at only selected portions of the cover106 (e.g., the septal wall114). In other embodiments, theribs530 can have different shapes and/or geometries on different portions of thecover106. For example, theapices533 of theribs530 can have a first height on thesuperior portion108 to enhance sealing forces between the endograft devices and a second height less than the first height at theinferior portion110 to allow thecover106 to freely flex and bend to accommodate the anatomy.
• Theribs530 change with the expansion and contraction of thecover106. As shown inFIG. 5A, theapices533 of theribs530 protrude to the maximal extent in the expanded configuration. Referring toFIG. 5B, as thecover106 extends, theribs530 also extend and constrict. When thecover106 is fully extended in the low-profile configuration shownFIG. 5C, theribs530 are completely elongated and constricted. In some embodiments, the size of eachrib530 can be predetermined to ensure theribs530 are completely flattened in the low-profile configuration and project radially outwardly to interface with adjacent surfaces in the expanded configuration. Accordingly, theribs530 do not limit the mobility of the endograft device as it is delivered to the aorta in the low-profile configuration.
• Additionally, as shown inFIGS. 5A-C, thecover106 can include zigzagged edges at asuperior terminus531aand aninferior terminus531bof thecover106. The zigzaggedtermini531 can facilitate substantially seamless attachment between thecover106 and an integrated frame (e.g., theframe104 shown inFIGS. 4A and 4B). For example, in some embodiments, the zigzaggedtermini531 can correspond to the braid angle θ of interwoven wires. The zigzaggedtermini531 generally prevent thecover106 from wrinkling or bunching at first and second end portions (e.g., the first andsecond end portions118aand118bshown inFIGS. 4A and 4B) when thecover106 and the frame are constricted. In other embodiments, the superior andinferior termini531aand531bcan be scalloped, straight, and/or have another suitable shape that facilitates attachment and/or limits wrinkling.
• Thecover106 can be made from a substantially impermeable, biocompatible, and flexible material. For example, thecover106 can be made from synthetic polymers, polyurethanes, silicone materials, polyurethane/silicone combinations, rubber materials, woven and non-woven fabrics such as Dacron®, fluoropolymer compositions such as a polytetrafluoroethylene (PTFE) materials, expanded PTFE materials (ePTFE) such as TEFLON®, GORE-TEX®, SOFTFORM®, IMPRA®, and/or other suitable materials. Additionally, in some embodiments, thecover106 can be made from a material that is sufficiently porous to permit ingrowth of endothelial cells. Such a porous material can provide more secure anchorages of endograft devices and potentially reduce flow resistance, sheer forces, and leakage of blood around the endograft devices.
• In some embodiments in accordance with the technology, thecover106 may also include drug-eluting coatings or implants. For example, thecover106 can be coated and/or imbedded with a slow-releasing drug that can block cell proliferation, promote reendothelialization of the aneurysm, and/or otherwise medicate the aneurysmal region. Suitable drugs can include calcium, proteins, mast cell inhibitors, and/or other suitable medicines that encourage beneficial changes at the aneurysmal region.
• In accordance with other embodiments of the technology, thecover106 can be eliminated in favor of one or more layers of a coating material (shown and described in more detail with reference toFIGS. 17A-E). The coating layer can be made from a biocompatible synthetic polymer, such as PTFE. The coating layer can be placed on the interior of an integrated frame (e.g., theframe104 shown inFIGS. 4A and 4B), the exterior of the frame, and/or interwoven throughout the frame. Like thecover106, the coating layers can encase the frame to form a lumen (e.g., thelumen116 shown inFIGS. 1A and 1B). Additionally, the coating can have a selected porosity that encourages tissue ingrowth.
• 2.3 Integrated Frame and Cover
• FIGS. 6A and 6B are cross-sectional views of theendograft device102 ofFIGS. 1A and 1B in a low-profile configuration and an expanded configuration, respectively, in accordance with embodiments of the technology. As shown inFIGS. 6A and 6B, thecover106 can be attached to the exterior of theframe104 at one or more attachment areas632 (identified individually as afirst attachment area632aand asecond attachment area632b). The attachment areas632 can have sutures, adhesives, welds, and/or other suitable fasteners that discretely hold thecover106 to theframe104 at the attachment areas632.
• In the embodiment shown inFIGS. 6A and 6B, theendograft device102 has attachment areas632 at only the superior andinferior termini531aand531bof thecover106 such that the remainder of thecover106 between the attachment areas632 is not attached directly theframe104. As a result, theframe104 and thecover106 can fully extend and constrict as shown inFIG. 6A without interfering with one another. For example, in the low-profile configuration shown inFIG. 6A, theframe104 does not directly pull the central portion of thecover106 downward and longitudinally with theframe104 such that theribs530 can stretch uniformly along the length of thecover106 to accommodate full extension of theframe104. Similarly, the intermediate portions of thecover106 do not hinder the extension or constriction of theframe104. Fewer attachments areas632 can also limit the potential for fatigue and undesirable porosity that may arise at the attachment areas632, such as from needle pricks and other fastening mechanisms that puncture thecover106.
• As shown inFIG. 6B, thecover106 can substantially conform to the shape of theframe104 when they are in the expanded configuration. Proper alignment between thecover106 and theframe104 prevents thecover106 from adversely affecting constriction and expansion. For example, alignment between thecover106 and theframe104 at the superior andtransition portions108 and324, respectively, ensures theframe104 can expand properly and generate the force necessary to mate with a superior portion of an opposing endograft device. Additionally, in some embodiments, thecover106 is sized to restrict the expansion and corresponding contraction of theframe104.
• Attaching thecover106 to the exterior of theframe104 as shown inFIGS. 6A and 6B can provide a plurality of benefits for theendograft device102. For example, unlike endograft devices with internal covers that must fold within a frame during delivery, theexterior cover106 does not inhibit constriction of the frame104 (e.g.,FIG. 6A). In the expanded configuration, the exterior thecover106 does not bunch or wrinkle within theframe104, and thus does not cause thrombotic problems within thelumen116. Additionally, unlike more rigid Z-stents, the flexibility of theframe104 can prevent abrasive rubbing and deterioration of thecover106 in the expanded configuration (e.g.,FIG. 6B). The exterior attachment of thecover106 can also prevent over expansion of theframe104.
• 2.4 Alignment Aids
• FIGS. 7A and 7B are isometric views ofendograft devices702 in accordance with additional embodiments of the technology. Theendograft devices702 can have generally similar features as theendograft devices102 shown inFIGS. 1A and 1B. Additionally, theendograft devices702 can include alignment aids734 that are visible under imaging systems (e.g., X-rays) to facilitate accurate positioning and subsequent monitoring of theendograft devices702 in the vasculature.
• FIG. 7A is a partial cut-away isometric view of the endograft device7-2 showing analignment aid734 in accordance with an embodiment of the technology. As shown inFIG. 7A, thealignment aid734 can extend diagonally along theseptal wall114 of theframe104 to indicate the position of theseptal wall114 relative to theendograft device702. Thealignment aid734 can thus provide an indication of the rotational orientation and axial location of theendograft device702 such that during deployment opposingseptal walls114 can be properly aligned and mated with one another. Additionally, as shown in the embodiment inFIG. 7A, thealignment aid734 can terminate at thesuperior terminus531aof thecover106 to indicate where thefirst end portion118abegins. Thus, thealignment aid734 provides a definitive indicator to ensure that thecover106 does not block transverse flow (e.g., from the aorta to the renal arteries). In other embodiments, the alignment aids734 may be positioned elsewhere along theendograft device702 to provide spatial location and orientation that can aid delivery and deployment of theendograft device702.
• Thealignment aid734 can be made from radiopaque and/or fluoroscopic materials, such as tantalum, platinum, gold, and/or other materials that are visible under an imaging system (e.g., X-rays). For example, as shown inFIG. 7A, thealignment aid734 is made from a radiopaque wire (e.g., tantalum) wound around a segment of theframe104. In another embodiment, a radiopaque composition is applied to theframe104 and/or incorporated in theseptal walls114 of thecover106.
• FIG. 7B shows the first andsecond endograft devices702 mated together using the alignment aids734 in accordance with an embodiment of the technology. As shown inFIG. 7B, the alignment aids734 on the first andsecond endograft devices702aand702bare symmetrical such that when theendograft devices702 are correctly oriented and theseptal walls114 oppose one another, the alignment aids734 can intersect to form an “X” indicator. In other embodiments, the intersection of the alignment aids734 forms other characters, numbers, and/or symbols that indicate the rotational orientation and longitudinal location of theendograft devices702. In further embodiments, the alignment aids734 can be applied to different portions of the septal wall (e.g., the cover102) and/or theouter wall112. In still further embodiments, theendograft devices702 include a plurality of alignment aids734 to distinguish different portions of theendograft devices702 and further aid rotational and/or other orientation. For example, in some embodiments, theinferior portions110 include alignment aids734 that differentiate theinferior portions110 of the first andsecond endograft devices702.
• 2.5 Anchors
• FIGS. 8A and 8B are isometric views ofendograft devices802 configured in accordance with additional embodiments of the technology. Theendograft devices802 can include generally similar features as theendograft devices102 shown inFIGS. 1A and 1B. Additionally, theendograft devices802 can include one ormore anchors836 that project outwardly from theframe104 and/or cover106 to engage the interior surfaces of arterial walls. Theanchors836 can be barbs, hooks, and or other shapes that can penetrate into the arterial walls. For example, as shown inFIG. 8A, theanchors836 can be “V” shaped projections. In some embodiments, theanchors836 eventually become embedded in cell growth on the interior surface of the arterial wall. In operation, theanchors836 resist migration of theendograft devices802 within the artery and reduce the likelihood of endoleaks between theouter wall112 and the arterial wall.
• In an embodiment shown inFIGS. 8A and 8B, theanchors836 project from theouter walls112 to secure thesuperior portions108 to the aorta. In other embodiments,additional anchors836 can project from thesecond end portions118bto secure theinferior portions110 to the iliac arteries. Theanchors836 can also protrude from theseptal walls114, extend through thelumen116, and project outward beyond theouter wall112 to enhance the strength of the engagement. The anchors generally project inferiorly such that downward forces applied to the endograft devices802 (e.g., blood flow) drive theanchors836 further into the arterial walls.
• In one embodiment in accordance with the technology, theanchors836 are separate elements that are attached to theframe104. For example, in the embodiment shown inFIG. 8A, theanchors836 are small barbs or wires that are fastened to theframe104 by winding another wire (e.g., a Nitinol wire) around theanchors836 and theadjacent wire426 of the braid. In other embodiments, the anchors326 are integrally formed with thewire426 used in the braid of theframe104. For example, as shown inFIG. 8B, theanchors836 are woven into theouter wall112 of theframe104. The interwoven anchors836 can be deployed (i.e., project outwardly) when theframe104 expands and can retract when theframe104 constricts. Accordingly, the interwovenanchors836 do not inhibit movement of theendograft device802 during delivery in the low-profile configuration. In other embodiments, theanchors836 can be attached to a different portion of the endograft device802 (e.g., the cover106).
• Theanchors836 can be made from resilient metallic materials, polymeric materials (e.g., polyethylenes, polypropylenes, Nylons, PTFEs), and/or other suitable materials that can anchor theendograft devices802 to arterial walls. For example, the interwovenanchors836 shown inFIG. 8B can be made fromNitinol wire426 that comprises theframe104.
• 3.Methods of Implementation and Assembled Endograft Systems
• Described below are methods of deploying and assembling modular endograft systems across an aneurysm in accordance with embodiments of the technology. The associated Figures (i.e.,FIGS. 9A,9B,11-13C and15A-16) include schematic representations of an abdominal portion of an aorta. More specifically,FIG. 9A shows ananeurysm50 located along an infrarenal portion of theaorta52, which is the most common site of an AAA. A right or firstrenal artery54aand a left or secondrenal artery54bstem from theaorta52. The region of theaorta52 superior to theaneurysm50 and inferior to the renal arteries54 is theaortic neck60. The distal end portion of theaorta52 bifurcates into common iliac arteries56 (identified individually as a firstiliac artery56aand a secondiliac artery56b), and the internal iliac arteries58 (identified individually as a first internaliliac artery58aand a second internaliliac artery58b) branch from the common iliac arteries56. Other arteries and structures proximate to the abdominal portion of theaorta52 have been removed for clarity.
• 3.1 Modular Endograft Systems
• FIGS. 9A and 9B are schematic views of the two-partmodular endograft system100 described above being deployed across theaneurysm50 in accordance with an embodiment of the technology.FIG. 9A shows adelivery system40 for implanting the first andsecond endograft devices102aand102b.The delivery system can include afirst catheter42a,afirst guidewire44aassociated with thefirst catheter42a,asecond catheter42b,and asecond guidewire44bassociated with thesecond catheter42b.Each endograft device102 (FIG. 9B) can be extended to the low-profile configuration and loaded into the corresponding catheter42. Because theendograft devices102 are delivered separately, the sizes of the catheters42 are not constrained by thesystem100 as a whole. In some embodiments, for example, the low-profile configurations of eachendograft device102 can fit within a 12 F catheter. In other embodiments, the low-profile configuration of theendograft devices102 can fit within differently sized catheters42.
• During deployment, thefirst catheter42aand thefirst guidewire44aare inserted percutaneously into a blood vessel (e.g., a femoral artery; not shown). With the aid of imaging systems, thefirst guidewire44ais endoluminally navigated through the vasculature, up the firstiliac artery56a,and to a location superior to a target site T above theaneurysm50. Thefirst catheter42ais then passed through the vasculature along thefirst guidewire44ato the target site T. Using a generally similar method, thesecond guidewire44band thesecond catheter42bare delivered through the secondiliac artery56bto the target site T. The first andsecond endograft devices102aand102bcan be delivered simultaneously or in succession.
• Theendograft devices102 can be urged out of the distal ends of the catheters42 at the target site T by withdrawing the catheters42 proximally while holding theendograft devices102 in place using pushers or other suitable endovascular instruments. Alternatively, theendograft devices102 can be pushed distally while holding the catheters42 in place. Upon release, theendograft devices102 self-expand to the expanded configuration shown inFIG. 9B. The guidewires44 generally remain in place to facilitate adjusting theendograft devices102. This eliminates the need to cannulate either of theendograft devices102.
• Eachendograft device102 can be positioned at its desired location independently of theother endograft device102 while theendograft devices102 are in, or at least partially within, the catheters42. For example, in the embodiment illustrated inFIG. 9B, thesuperior portions108 contact theaortic neck60 at the same level, and theinferior portions110 extend through theaneurysm50 to their respective iliac arteries56. More specifically, the inherent hoop force of theframe104 caused by the constant outward spring force of the braid at least substantially seals (a) thecovers106 at theouter walls112 against theaortic neck60 and (b) theseptal walls114 to each other to form theseptum120. Theinferior portions110 extend through theaneurysm50 and can bend to enter the iliac arteries56. The proximal portion of theinferior portions110 contact the iliac arteries56 and can form a seal therebetween. The flexibility of theframe104 prevents theendograft devices102 from kinking at the bend and restricting blood flow. Additionally, as shown inFIG. 9B, the spring force within theframe104 biases theinferior portions110 to extend in a substantially straight trajectory through theaneurysm50. This inhibits migration of theinferior portions110 to a side of theaneurysm50 that could break the contact and/or seal at theaortic neck60. As described in more detail below, in other embodiments theendograft devices102 can be positioned independently at different elevations along theaortic neck60.
• As further shown inFIG. 9B, theendograft system100 can include extension units937 (identified individually as afirst extension unit937aand asecond extension unit937b) projecting distally from thesuperior termini531 of thecovers106. The extension units937 can include an extension frame904 (not visible) and anextension cover906 at least generally similar to theframe104 and thecover106 of theendograft devices102 described above. The extension units937 can have a substantially similar shape as thesuperior portions108 of the endograft devices (e.g., a D-like shape) such that the extension units937 can mate with the interior of at least a part of thesuperior portions108. For example, as shown inFIG. 9B, the extension covers906 can be positioned inferior to the renal arteries54 within theframe104 such that the extension covers906 can interface with theaortic neck60 and mate with one another to extend theseptum120 distally. Therefore, the extension units937 can increase the fixation area and the sealing area of theendograft devices102 when thesuperior termini531 of thecovers106 of theendograft devices102 are offset from the entrances of the renal arteries54. For example, in some embodiments, the extension units937 add approximately one inch of fixation structure and sealing area to theendograft devices102. In other embodiments, theinferior portions110 can also include extension units937 that can affix and at least substantially seal to the iliac arteries56.
• During deployment, the extension units937 can be added to thesystem100 after the first andsecond endograft devices102 are positioned within theaortic neck60. With the aid of thedelivery system40, the extension units937 can advance along the guidewires44 and be deployed from the catheters42 at desired positions within the first andsecond frames104 just inferior of the renal arteries. Upon deployment, the extension units937 can self-expand via an inherent spring force in the extension frame904 to an expanded configuration to contact and at least substantially seal with the interior of thesuperior portions108 of theendograft devices102. As shown inFIG. 9B, theextension cover906 can interface with thefirst end portions118aof theframes104 to strengthen the seal therebetween. In other embodiments, the extension units937 can connect and seal to theendograft devices102 using other suitable attachment methods. The extension units937 can be positioned independently such that they accommodate anatomical variations (e.g. staggered renal arteries). For example, a superior terminus of thefirst extension unit937acan be longitudinally offset from a superior terminus of thesecond extension units937b.Similarly, theinferior portions110 can include extension units937 that increase the sealing area with the iliac arteries56.
• In some embodiments, alignment aids, such as the alignment aids734 described with reference toFIGS. 7A and 7B, are used to rotationally orient theendograft devices102 and align theseptal walls114 during delivery. Additionally, to prevent migration and/or projection of the system while in situ, anchors, such as theanchors836 described above with reference toFIGS. 8A and 8B, can be deployed from theouter walls112 to engage the arterial walls of theaortic neck60 and/or from thesecond end portions118bto engage the arterial walls of the iliac arteries56.
• FIGS. 10A-11 show additional embodiments of implementing endograft systems (e.g., the system100) in which thesuperior portions108 are longitudinally offset from each other. For example, in some embodiments, thesuperior portions108 are longitudinally offset by at least 5 mm. The features of the systems below allow one or both of thesuperior portions108 to be placed over transverse arteries to increase the available fixation structure and sealing area for theendograft devices102 without inhibiting blood flow.
• FIG. 10A is an isometric view of themodular endograft system100 in which theendograft devices102 are staggered such that thesuperior portion108 of thefirst endograft device102ais above thesuperior portion108 of thesecond endograft device102b.Thefirst end portion118aof thesecond endograft device102bcan prevent the unsupported freefirst end portion118aof thefirst endograft device102afrom splaying outward into the blood flow in a manner that induces undo turbulence. Moreover, the interplay between thewoven wires426 of theframe104 of thefirst endograft device102arestricts the outward movement of thefirst end portion118aof thefirst endograft device102aand provides substantially continuous support along the length of theframe104 such the freefirst end portion118aretains substantially the same shape as if it were supported. These features maintain the generally straight or convex shape of the unsupported septal region of thefirst portion118aof thefirst endograft device102a.Using shape-settingNitinol wire426 in theframe104 can further facilitate maintaining the shape of the unsupported portion of theframe104.
• Compared to conventional devices that have a common height across the diameter of a vessel (e.g., the aorta), the staggered configuration shown inFIG. 10A allows one or both of thefirst end portions118ato extend over the entrance of the renal arteries to increase the available structure for fixing theendograft devices102 to the vessel wall. The staggered configuration also increases the sealing area of the superiorly positionedfirst endograft device102afor anatomies having a short aortic neck (e.g., less than 2 cm). Similarly, thesecond end portions118bcan extend over the entrances of the internal iliac arteries to ensure theinferior portions110 each have an adequate structure for fixing and at least substantially sealing theinferior portions110 to the iliac arteries. To the extent migration occurs, the additional sealing area between theendograft devices102 and the vessel walls will reduce the potential for leakage at the aortic neck.
• FIG. 10B is an isometric view of amodular endograft system1000 configured in accordance with an additional embodiment of the technology. Thesystem1000 can have afirst endograft device1002aand asecond endograft device1002bthat are generally similar to theendograft devices102 described above. Thecovers106 of the endograft devices1002 inFIG. 10B, however, extend to the distal ends of thesuperior portions108. Additionally, the endograft devices1002 further includefenestrations1038 on theouter walls112 of thesuperior portions108.
• Thefenestrations1038 can be openings through thecover106 that expose theframe104 and provide a channel through which blood can flow to and from transverse arteries. For example, the endograft devices1002 can be positioned independently and staggered such that thefenestration1038 of each endograft device1002 is aligned with one of the left or right renal arteries. Thefenestrations1038 accordingly increase the available sealing area between theouter walls112 and the arterial walls because thesuperior portions108 can be positioned independently over the renal arteries such that one endograft device1002 does not need to be limited to the elevation of the inferior renal artery. This provides optimal placement for each endograft device1002 within the vasculature without requiring customized devices. In other embodiments in accordance with the technology, the endograft devices1002 can includeadditional fenestrations1038 to increase the available sealing area without restricting blood flow. For example, theinferior portions110 can includefenestrations1038 that allow theinferior portions110 to extend over the entrance of the internal iliac arteries.
• FIG. 11A is a schematic view of themodular endograft system100 deployed across an aneurysm such that thesuperior portions108 of theendograft devices102 are staggered to accommodate for anatomical variations in the vasculature in a manner that takes advantage of the available structure for fixing theendograft devices102 to arterial walls and the available sealing area in theaortic neck60. In the embodiment shown inFIG. 11A, for example, the leftrenal artery54bis inferior the rightrenal artery54a.Thefirst endograft device102acan, therefore, also be positioned higher in theaorta52 to utilize the available fixation and sealing areas on the ipsilateral side of theaortic neck60 without having to be concerned about blocking the entrance of the leftrenal artery54b.Thefirst end portion118aof thesecond endograft device102bcan be positioned over the leftrenal artery54bwithout inhibiting blood flow to lengthen the structure for fixing thesecond endograft device102bto the arterial wall and mating theseptal walls114 together. The longer fixation and sealing areas along theouter wall112 of thefirst endograft device102aand the longer mating and sealing areas between theseptal walls114 can strengthen the seals of thesystem100 as a whole to reduce the likelihood of endoleaks. Additionally, as shown inFIG. 11A, thesystem100 can be staggered to accommodate an anatomy with less fixation and sealing area in one of the iliac arteries56.
• FIG. 11B is a schematic view of themodular endograft system1000 ofFIG. 10B deployed across theaneurysm60. Similar to the configuration of thesystem100 shown inFIG. 11A, the endograft devices1002 are staggered to accommodate for anatomical variations in the vasculature in a manner that takes advantage of the available anatomical structure for fixing and sealing theouter walls112 of theendograft devices102 to the arterial walls in theaortic neck60. As shown inFIG. 11B, for example, thefirst endograft device1002acan be positioned superior to thesecond endograft device1002bin theaortic neck60 to utilize the available fixation and sealing area on the ipsilateral side of theaortic neck60. Thefenestrations1038 can be placed independently at the entrance of each renal artery54 to increase the available fixation and sealing area in theaortic neck60 and accommodate asymmetrical anatomies. Additionally, as further shown inFIG. 11B, the endograft devices can includefenestrations1038 at theinferior portions110 that can be placed independently at the entrance of each internal iliac artery58 to accommodate an anatomy with less sealing area in the iliac arteries56. In other embodiments, theendograft devices102 can includefenestrations1038 to accommodate other anatomical variations.
• FIG. 12 is a schematic view of the modular endograft system ofFIGS. 9A and 9B deployed across an angulated aneurysm in accordance with an additional embodiment of the technology. Thesystem100 can accommodate this anatomical abnormality because theendograft devices102 are flexible. More specifically, the interwovenwires426 of theframe104 are sufficiently flexibility to bend without kinking. Thus, thebent endograft devices102 can maintain unrestricted flow through thelumens116. Accordingly, thesystem100 can accommodate other anatomical variations that may require theendograft devices102 to flex or bend without disturbing blood flow.
• FIGS. 13A-C are schematic views of a four-partmodular endograft1300 system (“system1300”) being deployed across theaneurysm50 in accordance with an embodiment of the technology. Thesystem1300 can include generally similar features as thesystem100 described with reference toFIGS. 9A and 9B. However, as shown inFIG. 13B, theinferior portions110 of theendograft devices102 terminate within theaneurysm50. Therefore, as shown inFIG. 13C, thesystem1300 further includes separate limbs1362 (identified individually as afirst limb1362aand asecond limb1362b) that contact and substantially seal with correspondinginferior portions110 and extend into corresponding iliac arteries56. The limbs1362 can be generally similar to theinferior portions110. For example, the limbs1362 can include anintegrated frame1304 and acover1306 generally similar to theframe104 and thecover106 described above with reference toFIGS. 1A-6B. As shown inFIG. 13C, the limbs1362 self-expand within theinterior portions110 to the expanded configuration and thereby the superior portions of the limbs1362 at least substantially seals to the proximal section of theinferior portions110. The length of the limbs1362 within theinferior portions110 can be adjusted to increase the available structure for fixing and sealing the limbs1362 to theendograft devices102. Additionally, in some embodiments, thecovers1306 of the limbs1362 can include ribs, such as theribs530 described above with reference toFIGS. 5A-C, that interface with the interior of theframes104 and thecovers106 at theinferior portions110 to connect and at least substantially seal the limbs1362 to theinferior portions110. In other embodiments, the limbs1362 can connect and at least substantially seal to the exteriors of theinferior portions110 using anchors (e.g., theanchors836 described with reference toFIGS. 8A and 8B), self-constricting forces, and/or, other suitable attachment and sealing methods. The limbs1362 extend thelumens116 of theendograft devices102 to the iliac arteries56 such that blood can flow through thesystem1300 to bypass theaneurysm50.
• Referring toFIG. 13A, thedelivery system40 is shown within the abdominal portion of theaorta52 before deploying theendograft system1300. The insertion of thedelivery system40 can be generally similar as described above with reference toFIG. 9A. However, as shown inFIG. 13A, the first andsecond guidewires44aand44bcan cross after they enter theaneurysm50 such that each catheter42 extends from its respective iliac artery54 to the contralateral side of theaorta52. For example, thefirst catheter42acan be delivered from the firstiliac artery56ato the left side of theaorta52 proximate to the leftrenal artery54b(Arrow D₁), and thesecond catheter42bcan be delivered from the secondiliac artery56bto the rightrenal artery54a(Arrow D₂). In other embodiments, such as in the deployment method described above with reference toFIGS. 9A and 9B, the guidewires44 do not cross within theaneurysm50.
• Referring toFIG. 13B, after the first andsecond catheters42aand42bare positioned in theaortic neck60, they are pulled proximally to deploy theendograft devices102 through the distal ends of the catheters42. The crossing catheters42 and guidewires44 deploy theendograft devices102 on opposite sides of theaortic neck60.
• As shown inFIG. 13B, theinferior portions110 of theendograft devices102 terminate within theaneurysm50 and form a “gate.” In general, gates are considered undesirable because in conventional systems they must be cannulated to deliver and deploy limbs that extend the endograft devices into the iliac arteries56. However, as shown inFIG. 13B, the guidewires44 remain within theendograft devices102 after they are deployed; this eliminates the need for time-consuming cannulation of the gates because theinferior portions110 of theendograft devices102 are in effect pre-cannulated. Such pre-cannulated gates allow the limbs1362 to be delivered through the distal ends of the catheters42 and connected to theinferior portions110 much faster and more accurately than conventional systems.
• FIG. 13C shows thesystem1300 after both limbs1362 are connected to theendograft devices102. As shown inFIG. 13C, thedelivery system40 can also be used to adjust the length of the limbs1362 and the length of the fixation area between the limbs1362 and theinferior portions110 in the direction of the arrows. In the embodiment shown inFIG. 13C, for example, thesecond limb1362bextends further into theinferior portion110 of thesecond endograft device102bsuch that thesecond limb1362bis effectively shorter than thefirst limb1362a.The length of the limbs1362 can be adjusted to accommodate disparate anatomies of the iliac arteries56, maximize the fixation and sealing areas of the limbs1362, and/or otherwise optimize the position of the limbs1362. This is possible because, at least in part, theinferior portions110 of theendograft devices102 can be relatively long to allow significant longitudinal leeway in positioning the limbs1362 while still providing adequate surface area to at least substantially seal the limbs1362 to theinferior portions110.
• The four-part, two-wire system1300 can easily accommodate anatomical variations without requiring customized components. For example, thesuperior portions108 can be staggered to maximize the mating and sealing area of eachouter wall112 with the aortic walls. Additionally, each limb1362 can be selected from a relatively small number of different lengths to extend a desired length within the iliac arteries56 that both adequately connects and substantially seals the limbs1362 to the arterial walls and does not block transverse arterial flow. The limbs1362 can also be adjusted independently relative to theinferior portions110 to increase the available structure for fixing and sealing the limbs1362 and theinferior portions110 together, and to shorten or lengthen the limbs1362 within the iliac arteries56. Additionally, the braided structure of theframes104 can decrease infolding of thecovers106 such that the lengths of theframe104 can be selected from standardized cross-sectional dimensions. Thus, the four-part system1300 can be highly customizable, but yet comprise standardized components.
• 3.2 Modular Endograft System with Aortic Cuff
• FIGS. 14A and 14B are isometric views of a modular endograft system1400 (“system1400” shown inFIG. 14B) configured in accordance with embodiments of the technology. More specifically,FIG. 14A is an isometric view of anaortic cuff1464 for use with the endograft devices102 (FIG. 14B). Theaortic cuff1464 can include asleeve1466 and acuff frame1468. As shown inFIG. 14A, thesleeve1466 and thecuff frame1468 can be separate components. In other embodiments, thesleeve1466 and thecuff frame1468 can be formed integrally. Theaortic cuff1464 can expand from a low-profile configuration having a first cross-section to an expanded configuration (e.g.,FIG. 14B) having a second cross-section larger than the first cross-section. The low-profile configuration can be used during delivery of theaortic cuff1464 from which the cuff-device1464 can self-expand to the expanded configuration in situ. Theaortic cuff1464 can be configured to interface and substantially seal with an infrarenal portion of the aorta superior to an aneurysm.
• Thesleeve1466 can be attached to the interior and/or exterior of thecuff frame1468 using suitable fastening methods. For example, as shown inFIG. 14B, thesleeve1466 is positioned within the interior of thecuff frame1468, and the ends of thesleeve1466 extend over and are fixed to proximal and distal ends of thecuff frame1468 using suitable fastening methods (e.g., stitching, gluing, welding, etc.). In some embodiments, the proximal and distal ends of thecuff frame1468 can be flared, and thesleeve1466 can wrap around the flared ends to the exterior of thecuff frame1468 such that the attachment can be sealed by the arterial walls when theaortic cuff1464 is expanded to the expanded configuration in situ. Thesleeve1466 can have generally similar characteristics as thecover106 described above. For example, thesleeve1466 can be made from one or more substantially impermeable materials, such as Dacron® and PTFE, and can include ribs that can interface with arterial walls and/or endograft devices102 (FIG. 14B). Thecuff frame1468 can have generally similar characteristics as theintegrated frame104 described above. In other embodiments, thecuff frame1468 can be made from individual zigzagged wire hoops like a Z-stent.
• Thesleeve1466 and thecuff frame1468 can have a substantially cylindrical shape. In some embodiments, theaortic cuff1464 can include two channels to supportsuperior portions108 of endograft devices102 (FIG. 14B). For example, the channels can be formed by stitching the fabric of thesleeve1466 together to divide the interior of theaortic cuff1464. Additionally, thesleeve1466 and/or thecuff frame1468 can have flared proximal and distal ends to form a stronger seal with adjacent arterial walls.
• Referring toFIG. 14B, theendograft devices102 are deployed within theaortic cuff1464 after thecuff1464 has been at least substantially sealed against theaortic neck60. Thesuperior portions108 can mate with and substantially seal to the interior of theaortic cuff1464. Theribs530 of thecover106 can interface with the interior surface of thesleeve1466 to further strengthen the seal. Additionally, theintegrated frame104 can further improve the seal between theendograft devices102 and theaortic cuff1464. For example, the cross-section of theframe104 in the expanded configuration can be slightly larger than an interior cross-section of theaortic cuff1464. As theendograft devices102 are deployed within theaortic cuff1464, the radial forces from the expansion of theendograft devices102 can strengthen the seal therebetween. Additionally, in some embodiments, thetransition portion324 of the endograft devices can mate with a complementary taper within theaortic cuff1464.
• In some embodiments in accordance with the technology, theaortic cuff1464 can include alignment aids, such as the alignment aids734 described above with reference toFIGS. 7A and 7B, to facilitate positioning theendograft devices102 within theaortic cuff1464. For example, theaortic cuff1464 and theouter walls112 of theendograft devices102 can include orthogonal alignment aids that intersect to indicate theendograft devices102 are properly aligned within theaortic cuff1464.
• In additional embodiments, theaortic cuff1464 can include anchors, such as theanchors836 described above with reference toFIGS. 8A and 8B, to secure the to secure thesystem1400 in situ. For example, thecuff frame1468 can include anchors that project radially outwardly and engage adjacent arterial walls.
• FIGS. 15A and 15B are schematic views of a three-part modular endograft system1500 (“system1500”) being deployed across theaneurysm50 in accordance with an embodiment of the technology. Thesystem1500 can include theendograft devices102 described with respect to thesystem100 and theaortic cuff1464 described above with reference toFIGS. 14A and 14B.
• Referring toFIG. 15A, thedelivery system40 can be inserted using a generally similar method as described above with reference toFIG. 9A. In the embodiment shown inFIG. 15A, however, thefirst catheter42aand thefirst guidewire44acan be inserted first to deliver the aortic cuff1464 (FIG. 15B) to the target site T. Theaortic cuff1464 can be deployed using a generally similar method as deploying theendograft devices102 described above with reference toFIGS. 9A and 9B. Thefirst guidewire44acan be used to adjust theaortic cuff1464 to a desired position in theaortic neck60.
• As shown inFIG. 15B, theendograft devices102 can be deployed within theaortic cuff1464. Theendograft devices102 can be deployed using a substantially similar method as described with reference toFIG. 9B. For example, theendograft devices102 can be delivered through the first and second catheters42 and positioned independently within theaortic cuff1464 using the guidewires44. Similar to the method of deploying thesuperior portions108 directly against the arterial walls described with reference toFIGS. 9B and 13B, here the outer walls of thesuperior portions108 can at least partially interface with the interior surface of theaortic cuff1464 such that the septal walls are aligned with each other to form the septum120 (not visible). In some embodiments in accordance with the technology, theaortic cuff1464 can include sections shaped to receive theendograft devices102 and thereby ease alignment. In further embodiments, thefirst endograft device102acan be anchored or otherwise secured to theaortic cuff1464 before deployment such that only thesecond endograft device102bmust be positioned within theaortic cuff1464.
• FIG. 16 is a schematic view of a modular endograft system1600 (“system1600”) being deployed across theaneurysm50 in accordance with another embodiment of the technology. The system1600 can be deployed using generally similar methods as thesystem1500 described above with reference toFIGS. 15A and 15B. As shown inFIG. 16, however, thesuperior portions108 project above theaortic cuff1464 such that thefirst end portions118aprovide additional structure for securing the endograft devices to the arterial walls of theaorta52. Additionally, theinferior portions110 of theendograft devices102 terminate within theaneurysm50. Therefore, the system1600 further includes limbs (not shown), such as the limbs1362 described above with reference toFIGS. 13A-C, that connect to theinferior portions110 and extend into the iliac arteries56. The catheters42 can be used to adjust the length of the limbs to accommodate differing anatomies of the iliac arteries56 and to maximize the fixation and sealing areas between the limbs and the arterial walls. Additionally, in some embodiments, the limbs can intersect (e.g., the limbs1362 shown inFIG. 13C) to strengthen the seal at theaortic neck60 and decrease the likelihood of endoleaks. Similar to the four-part system1300 described above, the five-part system1600 can accommodate anatomical variations without requiring customized components.
• In the embodiments illustrated inFIGS. 9A,9B,11-13C,15A,15B and16, theaneurysm50 is shown in the infrarenal portion of theaorta52 because this is the most common site of an AAA. In other embodiments in accordance with the technology, themodular endograft systems100,1000,1300,1500 and1600 can be deployed acrossaneurysms50 at different portions of theaorta52 or in other vessels altogether. For example, in some embodiments, theaneurysm50 can extend from the infrarenal portion of theaorta52 into one or both of the common iliac arteries56. Theinferior portions110 or the limbs1362 of thesystems100,1000,1300,1500 and1600 can extend past the diseased, aneurysmal portion of the iliac arteries56 without blocking blood flow to the internal iliac arteries58. In other embodiments, thesystems100,1000,1300,1500 and1600 can be deployed acrossaneurysms50 located in the supra renal portion of theaorta52 with thefenestrations1038 and/or thefirst end portions118apositioned at the entrance of the renal arteries54. In further embodiments, the systems described above can be deployed across aneurysms in other portions of the vasculature that benefit from the use of a bifurcated, bi-luminal modular endograft system that can be independently positioned.
• 4. Methods of Manufacturing
• 4.1 Integrated Frame
• Referring back toFIGS. 4A and 4B, theintegrated frame104 can be made by weaving or braiding onecontinuous wire426 in a pattern along a cylindrical mandrel. In some embodiments, thewire426 is woven with a one over and one under pattern. In other embodiments, thewire426 is woven with a two over and one under pattern, another integrated pattern, and/or a pattern that varies over the length of theframe104. The intersections of thewire426 can remain unbound to increase flexibility of theframe104. Thewire426 can form theloops428 to change direction and continue the pattern of intersectingwires426. As described above, the number ofloops428 at each end portion118 and the braid angle a can be selected based on the diameter of thewire426 and the desired properties of theframe104.
• Thewire426 can be removed from the mandrel after it is braided into theframe104 and formed into a desired shape (e.g., theendograft devices102 shown above). Theframe104 can then be heated to a shape-setting temperature specified for the wire material (e.g., Nitinol), and subsequently quenched. Optionally, theframe104 can be annealed to increase the strength of theframe104. The mandrel can be cylindrical or have the shape of theframe104 such that thewire426 remains on the mandrel during heat treatment. In further embodiments, theframe104 can be manufactured using other suitable methods for shaping resilient biocompatible materials.
• 4.2 Covers and Coatings
• Referring toFIGS. 5A-C, thecover106 can be made by shaping a substantially non-permeable cover material, such as Dacron®, PTFE, and/or other suitable biocompatible materials. Thecover106 can be formed by first placing the cover material over a mandrel. The mandrel can include thin grooves that can correspond to the desired geometry of theribs530 on thecover106. A wire or thread can be wrapped over the cover material and into the grooves to corrugate the cover material. The cover material can then be heated on the mandrel until theribs530 are formed and thecover106 is substantially non-permeable. In some embodiments, the superior andinferior termini531aand531bof thecover106 can be shaped to facilitate attaching thecover106 to a frame (e.g. theframe104 shown inFIGS. 4A and 4B) and prevent thecover106 from wrinkling at end portions (e.g., the end portions118 shown inFIGS. 1A and 1B) during constriction. For example, the superior andinferior termini531aand531bcan be zigzagged as shown inFIGS. 5A and 5B, scalloped, or otherwise shaped to limit wrinkling of the cover on the frame.
• In other embodiments in accordance with the technology, coating layers can be used in place of or in conjunction with thecover106.FIGS. 17A-E are views of coating layers being applied to an integrated frame1704 (“frame1704”) in accordance with embodiments of the technology. Theframe1704 has generally similar features as theframe104 described above. For example, theframe1704 can be made from thebraided wire426.
• Referring toFIG. 17A, theframe1704 is positioned over amandrel80 in the expanded configuration. As shown inFIG. 17A, afirst coating layer1770 can be wrapped onto theframe1704. Thefirst coating layer1770 can be a single or double layer of unsintered tape that can be approximately 0.0005″ thick and made from PTFE. In other embodiments, thefirst coating layer1770 can have a different thickness and/or thefirst coating layer1770 can be made from another suitable coating material.
• Once thefirst coating layer1770 is applied over theframe1704, thefirst coating layer1770 and theframe1704 can be heated on themandrel80 in an oven. For example, thefirst coating layer1770 and theframe1704 can be heated for less than thirty minutes in a 370° C. oven. After heating, thecoated frame1704 is removed from themandrel80 and extended and contracted from the low-profile configuration to the expanded configuration to ensure thefirst coating layer1770 properly adhered to theframe1704 during heat treatment.
• As shown inFIG. 17B, asecond coating material1772 is placed over a narrower,second mandrel82. Thesecond coating material1772 can be extended a distance equivalent to the length of theframe1704 in the low-profile configuration. Referring toFIG. 17C, thesecond coating material1772 is contracted to the length of theframe1704 in the expanded configuration. This contraction can formsmall ribs1730 in thesecond coating material1772. Theribs1730 can be generally similar to theribs530 described above with reference toFIGS. 5A-C, but they are on the interior of theframe1704. Theribs1730 prevent thesecond coating material1772 from wrinkling or bunching when the subsequently attachedframe1704 flexes or bends and thereby reduce the likelihood of thrombotic problems within the lumen.
• As shown inFIG. 17D, thecoated frame1704 is then extended to the low-profile configuration and placed over the extendedsecond coating material1772 on thesecond mandrel82. Each diamond opening along theframe1704 can be spot welded using awelding device84. Then, theframe1704 is removed from thesecond mandrel82 and extended and contracted from the low-profile configuration to the expanded configuration to ensure that the first andsecond coating layers1770 and1772 have adequately adhered to theframe1704. Additionally, the proximal and distal ends of theframe1704 are verified to ensure that the first andsecond coating layers1770 and1772 have properly adhered to theframe1704. If necessary, tacking can be performed and the edges can be trimmed to form a dualcoated endograft device1702 shown inFIG. 17E.
• From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the technology. For example, the embodiments illustrated inFIGS. 1A-16 includecovers106 that extend over the exterior of the integrated frames104. However, other embodiments of the technology can includecovers106 that are attached to the interior of theintegrated frame104 and/or are formed integrally with theframe104. Certain aspects of the new technology described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, in the embodiments illustrated above, each endograft device (e.g.,102,1002) includes asingular lumen116. However, the endograft devices can include additional lumens that transverse, bisect, and/or otherwise communicate with thelumen116 to accommodate the vasculature. For example, the endograft devices can include lumens that extend into the renal arteries, the internal iliac arteries, and/or other arteries. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claims (32)

1. A modular endograft system, comprising:

a first guidewire;

a first endograft device positioned along the first guidewire, the first endograft device having a first superior portion, a first inferior portion, and a first lumen through the first superior and inferior portions, and the first superior portion having a first outer wall and a first septal wall;

a first limb positioned along the first guidewire and coupled to the first inferior portion of the first endograft device;

a second guidewire;

a second endograft device positioned along the second guidewire, the second endograft device having a second superior portion, a second inferior portion, and a second lumen through the second superior and inferior portions, and the second superior portion having a second outer wall and a second septal wall, wherein the first septal wall of the first endograft device presses against the second septal wall of the second endograft device; and

a second limb positioned along the second guidewire and coupled to the second inferior portion of the second endograft device.

2. The modular endograft system ofclaim 1, wherein:

the first outer wall is convexly curved, and the first septal wall and first outer wall form a substantially D-shaped cross-section; and

the second outer wall is convexly curved, and the second septal wall and the second outer wall form a substantially D-shaped cross-section.

3. The modular endograft system ofclaim 2, wherein:

the first septal wall is convexly curved in a direction opposite the convex curvature of the first outer wall; and

the second septal wall is convexly curved in a direction opposite the convex curvature of the second outer wall.

4. The modular endograft system ofclaim 2, wherein the first and second septal walls are at least substantially straight and form a septum.

5. The modular endograft system ofclaim 2 wherein:

the first and second inferior portions of the first and second endograft devices have a circular cross-section; and

the first and second limbs have circular cross-sections.

6. The modular endograft system ofclaim 1 wherein:

the first endograft device has an integrated first frame (“first frame”) and a first cover exterior of the first frame, wherein the first lumen is within the first cover, and wherein the first cover has a first superior terminus and the first frame has a first end portion extending distally from the first superior terminus of the first cover; and

the second endograft device has an integrated second frame (“second frame”) and a second cover exterior of the second frame, wherein the second lumen is within the second cover, and wherein the second cover has a second superior terminus and the second frame has a first end extending distally from the second superior terminus of the second cover.

7. The modular endograft device ofclaim 6, wherein the first and second frames each include a superior terminus, an inferior terminus, and a continuous wire woven in a braid in which the wire crosses itself at a braid angle, and wherein the wire reverses direction at the superior terminus of the frame to form a first plurality of loops and reversing direction at the inferior terminus of the frame to form a second plurality of loops.

8. The modular endograft system ofclaim 7 wherein the wire is unbound where it crosses itself.

9. The modular endograft device ofclaim 7 wherein the braid angle is from approximately 30° to approximately 45°.

10. The modular endograft device ofclaim 6, wherein:

the first cover includes a plurality of first ribs, the first ribs protruding radially from the first frame in an expanded configuration and being extendable longitudinally in a low-profile configuration;

the second cover includes a plurality of second ribs, the second ribs protruding radially from the second frame in an expanded configuration and being extendable longitudinally in a low-profile configuration; and

wherein the first ribs on the first septal wall interface with the second ribs at the second septal wall in the expanded configuration.

11. The modular endograft device ofclaim 1 wherein:

the first superior portion has a cross-sectional dimension of at least 20 mm in an expanded configuration and a cross-sectional dimension of at most 5 mm in a low-profile configuration; and

the second superior portion has a cross-sectional dimension of at least 20 mm in an expanded configuration and a cross-sectional dimension of at most 5 mm in a low-profile configuration.

12. The modular endograft system ofclaim 1 wherein:

the first endograft device includes a plurality of first ribs;

the second endograft device includes a plurality of second ribs; and

the first ribs mate with the second ribs in an expanded configuration.

13. The modular endograft system ofclaim 1 wherein the first and second limbs each include a cover having a plurality of circumferential ribs protruding radially from the cover, the ribs of the first limb contacting an interior of the first inferior portion, and the ribs of the second limb contact an interior of the second inferior portion.

14. The modular endograft system ofclaim 1, further comprising:

a first alignment aid at the first septal wall;

a second alignment aid at the second septal wall, wherein the second alignment aid crosses the first alignment aid when the first and second septal walls are aligned; and wherein the first and second alignment aids comprise a radiopaque material.

15. A modular endograft system comprising:

a first guidewire;

a first endograft device positioned along the first guidewire, the first endograft device having a first superior portion, a first inferior portion, a first braided frame, and a first lumen through the first superior and inferior portions;

a first limb positioned along the first guidewire and coupled to the first inferior portion of the first endograft device;

a second guidewire;

a second endograft device positioned along the second guidewire, the second endograft device having a second superior portion, a second inferior portion, a second braided frame, and a second lumen through the second superior and inferior portions, wherein septal walls of the first and second endograft devices press against one another to form a septum; and

a second limb positioned along the second guidewire and coupled to the second inferior portion of the second endograft device; and

wherein the first and second braided frames are configured to have substantially continuous longitudinal support along the superior and inferior portions of the first and second endograft devices, respectively.

16. The modular endograft system ofclaim 15 wherein the first and second braided frames are woven from a wire such that each longitudinal segment of each frame supports adjacent longitudinal segments along the length of each frame.

17. The modular endograft system ofclaim 16 wherein each longitudinal segment of the frame influences the radial expansion or contraction of the adjacent longitudinal segment of the frame.

18. The modular endograft system ofclaim 15 wherein:

the first and second superior portions each include a convexly curved outer wall and a convexly curved septal wall, the outer walls having a first radius of curvature and the septal walls having a second radius of curvature less than the first radius of curvature such that the first and second superior portions have a substantially D-like cross-sectional shape; and

the first and second endograft devices expand via an inherent spring force such that opposing forces between the first and second septal walls are substantially uniform along the septum.

19. The modular endograft system ofclaim 15 wherein the first endograft device has a first alignment aid and the second endograft device has a second alignment aid, and wherein the first and second alignment aids are configured to indicate a rotational orientation and a longitudinal position of the first and second endograft devices relative to each other.

20. The modular endograft system ofclaim 15 wherein the first endograft device has a first cover attached to a portion of the first frame, and the first cover having a first opening, and wherein the first opening allows blood to flow laterally relative to the first lumen.

21. The modular endograft system ofclaim 15 wherein:

the first superior portion has a cross-sectional dimension of at least 20 mm in an expanded configuration and a cross-sectional dimension of at most 5 mm in a low-profile configuration; and

the second superior portion has a cross-sectional dimension of at least 20 mm in an expanded configuration and a cross-sectional dimension of at most 5 mm in a low-profile configuration.

22. The modular endograft system ofclaim 15 wherein:

the first and second endograft devices include first and second covers, respectively, the first and second covers having a plurality of circumferential ribs that protrude radially;

the first limb includes a third cover having a plurality of circumferential ribs that protrude radially;

the second limb includes a fourth cover having a plurality of circumferential ribs that protrude radially;

the third cover of the first limb contacts an interior of the first inferior portion of the first endograft device such that the ribs on the third cover interface with the ribs on the first cover of the first endograft device; and

the fourth cover of the second limb contacts an interior of the second inferior portion of the second endograft device such that the ribs on the fourth cover interface with the ribs on the second cover of the second endograft device.

23. The modular endograft device ofclaim 15 wherein:

the first endograft device includes a first transition portion between the first superior portion and the first inferior portion, the first transition portion tapering the first lumen from a first cross-sectional dimension at the superior portion to a second cross-sectional dimension less than the first cross-sectional dimension at the inferior portion, wherein the transition portion is configured to maintain substantially laminar blood flow through the first lumen in the expanded configuration; and

the second endograft device includes a second transition portion between the second superior portion and the second inferior portion, the second transition portion tapering the second lumen from the first cross-sectional dimension at the second superior portion to the second cross-sectional dimension at the second inferior portion, wherein the second transition portion is configured to maintain substantially laminar blood flow through the second lumen in the expanded configuration.

24. A method of treating an aneurysm in a primary vessel at a location before a bifurcation into a first vessel and a second vessel, the method comprising:

positioning a first endograft device over a first guidewire relative to the aneurysm such that at least a segment of a first superior portion of the first endograft device is positioned superior to the aneurysm and a first inferior portion of the first endograft device extends only partially through the aneurysm, the first superior portion having a convexly curved first outer wall and a first septal wall;

positioning a second endograft device over a second guidewire relative to the aneurysm such that at least a segment of a second superior portion of the second endograft device is positioned superior to the aneurysm and a second inferior portion of the second endograft device extends only partially through the aneurysm, the second superior portion having a convexly curved second outer wall and a second septal wall, and wherein the second endograft device is positioned independently of positioning the first endograft device;

deploying the first endograft device from a first catheter and deploying the second endograft device from a second catheter such that the first and second septal walls press against each other to form a septum between the first and second endograft devices;

implanting a first limb over the first guidewire such that a distal portion of the first limb is coupled to the first inferior portion of the first endograft device and a proximal portion of the first limb is in the first vessel; and

implanting a second limb over the second guidewire such that a distal portion of the second limb is coupled to the second inferior portion of the second endograft device and a proximal portion of the second limb is in the second vessel.

25. The method ofclaim 24, wherein the first septal wall is convexly curved in a direction opposite the first outer wall and the second septal wall is convexly curved in a direction opposite the second outer wall, and wherein deploying the first and second endograft devices comprises urging the convexly curved first and second septal walls together.

26. The method ofclaim 25 wherein urging the convexly curved first and second septal walls together results in a more uniform distribution of pressure between the first and second septal walls compared to straight first and second septal walls.

27. The method ofclaim 24 wherein positioning the first and second endograft devices comprises staggering the first superior portion of the first endograft device relative to the second superior portion of the second endograft device such that a portion of the first septal wall is positioned superior relative to a distal most terminus of the second septal wall.

28. The method ofclaim 24 wherein:

the first catheter has a maximum cross-sectional dimension of 5 mm and the first outer wall of the first superior portion of the first endograft device has a radius of curvature not less than 10 mm after being deployed from the first catheter; and

the second catheter has a maximum cross-sectional dimension of 5 mm and the second outer wall of the second superior portion of the second endograft device has a radius of curvature not less than 10 mm after being deployed from the second catheter.

29. The method ofclaim 24 wherein the first endograft device includes a first alignment aid at the first septal wall, wherein the second endograft device includes a second alignment aid at the second septal wall, the first and second alignment aids comprising a radiopaque material, and wherein deploying the first and second endograft devices further includes:

radiographically positioning the first and second alignment aids such that the first and second alignment aids oppose one another;

viewing the first and second alignment aids in the orthogonal plane; and

crossing the first and second alignment aids such that the first and second septal walls form the septum.

30. The method ofclaim 24 wherein the primary blood vessel includes a third blood vessel branching from the primary blood vessel before the aneurysm, and wherein:

the first endograft device includes a frame, a cover, and a lumen within the cover, wherein a superior end portion of the frame projects distally beyond a superior terminus of the cover; and

deploying the first and second endograft devices includes positioning the distal end portion of the first endograft device at the third blood vessel such that blood flows laterally through the distal end portion relative to a longitudinal axis of the lumen.

31. The method ofclaim 24 wherein implanting the first and second limbs further comprises:

positioning the distal portion of the first limb within the first inferior portion and expanding the first limb via an inherent spring force in the second limb to contact an internal surface of the first inferior portion; and

positioning the distal portion of the second limb within the second inferior portion and expanding the second limb via an inherent spring force in the second limb to contact an internal surface of the second inferior portion.

32. The method ofclaim 31 wherein positioning the distal portions of the first and second limbs further comprises:

adjusting the length of the first limb within the first inferior portion such that the proximal portion of the second limb presses against an interior the second vessel; and

adjusting a length of the second limb within the second inferior portion such that the proximal portion of the second limb presses against an interior the second vessel.

Images