Patent Description:
This invention relates generally to a modular assembly or system configured to perfuse the aortic arch via an endovascular approach.

Aneurysms, dissections, penetrating ulcers, intramural hematomas and/or transactions may occur in blood vessels, and most typically occur in the aorta and peripheral arteries. Depending on the region of the aorta involved, the aneurysm may extend into areas having vessel bifurcations or segments of the aorta from which smaller "branch" arteries extend. Various types of aortic aneurysms may be classified on the basis of the region of aneurysmal involvement. For example, thoracic aortic aneurysms include aneurysms present in the ascending thoracic aorta, the aortic arch, and branch arteries that emanate therefrom, such as subclavian arteries, and also include aneurysms present in the descending thoracic aorta and branch arteries that emanate therefrom, such as thoracic intercostal arteries and/or the suprarenal abdominal aorta and branch arteries that emanate therefrom, such as superior mesenteric, celiac and/or intercostal arteries. Lastly, abdominal aortic aneurysms include aneurysms present in the aorta below the diaphragm, e.g., pararenal aorta and the branch arteries that emanate therefrom, such as the renal arteries.

The thoracic aorta has numerous arterial branches. The arch of the aorta has three major branches extending therefrom, all of which usually arise from the convex upper surface of the arch and ascend through the superior thoracic aperture. The brachiocephalic artery originates anterior to the trachea. The brachiocephalic artery (BCA) divides into two branches, the right subclavian artery (which supplies blood to the right arm) and the right common carotid artery (which supplies blood to the right side of the head and neck). The left common carotid (LCC) artery arises from the arch of the aorta just to the left of the origin of the brachiocephalic artery. The left common carotid artery supplies blood to the left side of the head and neck. The third branch arising from the aortic arch, the left subclavian artery (LSA), originates behind and just to the left of the origin of the left common carotid artery and supplies blood to the left arm. However, a significant proportion of the population has only two great branch vessels coming off the aortic arch while others have four great branch vessels coming of the aortic arch. As will be explained in more detail herein, the distance(s) between the great branch vessels varies considerably amongst patients and the anatomical variation of the aortic arch complicates treatment thereof.

For patients with thoracic aneurysms of the aortic arch, surgery to replace the aorta may be performed where the aorta is replaced with a fabric substitute in an operation that uses a heart-lung machine. In such a case, the aneurysmal portion of the aorta is removed or opened, and a substitute lumen is sewn across the aneurysmal portion to span it. Such surgery is highly invasive, requires an extended recovery period and, therefore cannot be performed on individuals in fragile health or with other contraindicative factors.

Alternatively, the aneurysmal region of the aorta can be bypassed by use of an endoluminally delivered tubular exclusion device, e.g., by a stent-graft placed inside the vessel spanning the aneurysmal portion of the vessel, to seal off the aneurysmal portion from further exposure to blood flowing through the aorta. A stent-graft can be implanted without a chest incision, using specialized catheters that are introduced through arteries, usually through incisions in the groin region of the patient. The use of stent-grafts to internally bypass, within the aorta or flow lumen, the aneurysmal site, is also not without challenges. In particular, where a stent-graft is used at a thoracic location, care must be taken so that critical branch arteries are not covered or occluded by the stent-graft yet the stent-graft must seal against the aorta wall and provide a flow conduit for blood to flow past the aneurysmal site. Where the aneurysm is located immediately adjacent to the branch arteries, there is a need to deploy the stent-graft in a location which partially or fully extends across the location of the origin of the branch arteries from the aorta to ensure sealing of the stent-graft to the artery wall.

To accommodate side branches, main vessel stent-grafts having a fenestration or opening in a side wall thereof may be used. The main vessel stent-graft is positioned to align its fenestration with the ostium of the branch vessel. In use, a proximal end of the stent-graft, having one or more side openings, is prepositioned and securely anchored in place so that its fenestrations or openings are oriented when deployed to avoid blocking or restricting blood flow into the side branches. Fenestrations by themselves do not form a tight seal or include discrete conduit(s) through which blood can be channeled into the adjacent side branch artery. As a result, blood leakage is prone to occur into the space between the outer surface of the main aortic stent-graft and the surrounding aortic wall between the edge of the graft material surrounding the fenestrations and the adjacent vessel wall. Similar blood leakage can result from post-implantation migration or movement of the stent-graft causing misalignment between the fenestration(s) and the branch artery(ies), which may also result in impaired flow into the branch artery(ies).

In some cases, the main vessel stent-graft is supplemented by another stent-graft, often referred to as a branch stent-graft. The branch stent-graft is deployed through the fenestration into the branch vessel to provide a conduit for blood flow into the branch vessel. The branch stent-graft is preferably sealingly connected to the main stent-graft in situ to prevent undesired leakage between it and the main stent-graft. This connection between the branch stent-graft and main stent-graft may be difficult to create effectively in situ and is a site for potential leakage.

In some instances, branch stent-grafts are incorporated into or integrally formed with the main stent-graft as extensions thereof. Such integral branch stent-grafts extensions are folded or collapsed against the main stent-graft for delivery and require complicated procedures, requiring multiple sleeves and guide wires, to direct the branch stent-grafts extension into the branch vessel and subsequently expand. Further, in some instances, such branch stent-grafts extensions tend to return to their folded or collapsed configuration, and thus do not provide an unobstructed flow path to the branch vessel. Because the position or location of integral branch stent-grafts extensions is fixed on the stent-graft, there is no opportunity to ensure that each integral branch stent-grafts extension is optimally aligned with their intended target branch ostium. Offset alignment between the integral branch stent-grafts extension and target branch can make cannulation and branch stent-graft deployment difficult and put the patient at risk for occlusive stroke. Thus, integral branch stent-grafts extensions are not optimized to treat all patient anatomical variations which significantly limit patient applicability for these designs.

Another approach for treating variations in patient anatomy is utilization of a custom designed endovascular stent-graft. However, custom designed stent-grafts require a significant lead time, i.e., <NUM>-<NUM> weeks, and are costly to design and manufacture.

Thus, there remains a need in the art for improvements in stent-graft structures for directing flow from a main vessel, such as the aorta, into branch vessels emanating therefrom, such as branch vessels of the aortic arch. Document <CIT> relates to devices and methods for treatment of the aortic arch.

Embodiments hereof relate to a prosthetic assembly according to the appended claims configured for endovascular placement within an aortic arch, the prosthetic assembly including a proximal aortic stent-graft prosthesis, a distal aortic stent-graft prosthesis, a first branch stent-graft prosthesis and a second branch stent-graft prosthesis. The proximal aortic stent-graft prosthesis includes a tubular graft, at least one stent coupled to the tubular graft, and a coupling extending from the tubular graft. The coupling is configured to be positioned proximal to an ostium of a first branch vessel when deployed in situ. The distal aortic stent-graft prosthesis includes a tubular graft, at least one stent coupled to the tubular graft, and a coupling extending from the tubular graft. The first branch stent-graft prosthesis includes a tubular graft and at least one stent coupled to the tubular graft, and the first branch stent-graft prosthesis is configured to be disposed through the coupling of the proximal aortic stent-graft prosthesis when the proximal aortic stent-graft prosthesis and the first branch stent-graft prosthesis are each in an expanded configuration. The second branch stent-graft prosthesis including a tubular graft and at least one stent coupled to the tubular graft, and the second branch stent-graft prosthesis is configured to be disposed through the coupling of the distal aortic stent-graft prosthesis when the distal aortic stent-graft prosthesis and the second branch stent-graft prosthesis are each in an expanded configuration. A proximal end of the distal aortic stent-graft prosthesis is configured to be disposed within a distal end of the proximal aortic stent-graft prosthesis to form an overlap between the proximal and distal aortic stent-graft prostheses when the proximal and distal aortic stent-graft prostheses are in their respective expanded configurations. The overlap is relatively increased due to the coupling of the proximal aortic stent-graft prosthesis being positioned proximal to the ostium of the first branch vessel in situ.

In an embodiment hereof, the proximal aortic stent-graft prosthesis is configured to be positioned within a proximal portion of the aortic arch adjacent to the brachiocephalic artery, the distal aortic stent-graft prosthesis is configured to be positioned within a distal portion of the aortic arch adjacent to the left subclavian artery, the first branch stent-graft prosthesis is configured to be positioned within the brachiocephalic artery, and the second branch stent-graft prosthesis is configured to be positioned in one of the left common carotid and the left subclavian artery.

In an embodiment hereof, the proximal aortic stent-graft prosthesis includes a tubular graft, at least one stent coupled to the tubular graft, and a coupling extending from the tubular graft. The distal aortic stent-graft prosthesis includes a tubular graft, at least one stent coupled to the tubular graft, and a coupling extending from the tubular graft. The first branch stent-graft prosthesis includes a tubular graft and at least one stent coupled to the tubular graft, and the first branch stent-graft prosthesis is configured to be disposed through the coupling of the proximal aortic stent-graft prosthesis when the proximal aortic stent-graft prosthesis and the first branch stent-graft prosthesis are each in an expanded configuration. The second branch stent-graft prosthesis including a tubular graft and at least one stent coupled to the tubular graft, and the second branch stent-graft prosthesis is configured to be disposed through the coupling of the distal aortic stent-graft prosthesis when the distal aortic stent-graft prosthesis and the second branch stent-graft prosthesis are each in an expanded configuration. A proximal end of the distal aortic stent-graft prosthesis is configured to be disposed within a distal end of the proximal aortic stent-graft prosthesis to form an overlap between the proximal and distal aortic stent-graft prostheses when the proximal and distal aortic stent-graft prostheses are in their respective expanded configurations. A portion of the first branch stent-graft prosthesis in its expanded configuration extends along the overlap such that a proximal end of the first branch stent-graft prosthesis is positioned proximal to the overlap and effectively proximally reroutes an ostium of a first branch vessel in situ.

The present disclosure relates to a method of deploying a prosthetic assembly within an aortic arch. A proximal aortic stent-graft prosthesis is positioned within a proximal portion of the aortic arch adjacent to the brachiocephalic artery. The proximal aortic stent-graft prosthesis is in a compressed configuration for delivery. The proximal aortic stent-graft prosthesis is deployed into an expanded configuration. A first branch stent-graft prosthesis is positioned within the brachiocephalic artery and through a coupling of the proximal aortic stent-graft prosthesis. The first branch stent-graft prosthesis is in a compressed configuration for delivery. The first branch stent-graft prosthesis is deployed into an expanded configuration. A distal aortic stent-graft prosthesis is positioned within a distal portion of the aortic arch adjacent to the left subclavian artery. The distal aortic stent-graft prosthesis is in a compressed configuration for delivery. The distal aortic stent-graft prosthesis is expanded into an expanded configuration. A second branch stent-graft prosthesis is positioned within the left subclavian artery and through a coupling of the distal aortic stent-graft prosthesis. The second branch stent-graft prosthesis is in a compressed configuration for delivery. The second branch stent-graft prosthesis is deployed into an expanded configuration. A proximal end of the distal aortic stent-graft prosthesis is disposed within the distal end of the proximal aortic stent-graft prosthesis to form an overlap between the proximal and distal aortic stent-graft prostheses. The overlap is relatively increased by at least one of the first branch stent-graft prosthesis proximally displacing the ostium of the brachiocephalic artery and the second branch stent-graft prosthesis distally displacing the ostium of the left subclavian artery.

Specific embodiments are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. Unless otherwise indicated, for the delivery system the terms "distal" and "proximal" are used in the following description with respect to a position or direction relative to the treating clinician. "Distal" and "distally" are positions distant from or in a direction away from the clinician, and "proximal" and "proximally" are positions near or in a direction toward the clinician. For the stent-graft devices "proximal" is the portion nearer the heart by way of blood flow path while "distal" is the portion of the stent-graft further from the heart by way of blood flow path.

Although the description of embodiments hereof is primarily in the context of modular devices for treating aneurysm disease within an aortic arch, the modular devices described herein can also be used to treat other aortic arch pathologies including but not limited to dissections, penetrating ulcers, intramural hematomas, transections, and pseudoaneurysms.

Embodiments hereof relate to a modular assembly or system configured to perfuse the aortic arch via an endovascular approach. With reference to <FIG>, which is a schematic side view of an anatomy of an aortic arch (labeled as "AA" in the figures), the challenge of using a modular assembly in the aortic arch is further described. More particularly, adoption of a modular approach has been limited by the short distances between the great branch vessels of the aortic arch. Landing zone L1 extends between the brachiocephalic artery (BCA) and the left common carotid (LCC), while landing zone L2 extends between the left common carotid (LCC) and the left subclavian artery (LSA). Both landing zones, L1 and L2, are insufficient for a durable and sufficient overlap of adjacent modular components that may be deployed within the aortic arch. Insufficient overlap of adjacent modular components would leave the modular system prone to development of leaks. The problem of separation of modular components is exacerbated by the dynamic environment of the aortic arch where there is extensive cardiac and respiratory induced motion.

Embodiments hereof relate to an aortic arch prosthetic assembly <NUM> which is a modular assembly or system configured to perfuse the aortic arch and is configured to address the insufficient overlap issue that may be encountered by modular systems as described above. <FIG> illustrates an embodiment of aortic arch prosthetic assembly <NUM> in which a coupling <NUM> of a first or proximal aortic stent-graft prosthesis or module <NUM> is purposely positioned or configured to be positioned proximal to the ostium of the brachiocephalic artery to create or facilitate an adequate landing zone that permits sufficient overlap of adjacent modular components as will be explained in more detail herein. Aortic arch prosthetic assembly <NUM> is shown deployed and assembled in situ within an aortic arch in <FIG>, and is shown deployed and assembled but not in situ in <FIG>. Aortic arch prosthetic assembly <NUM> includes proximal aortic stent-graft prosthesis <NUM>, a second or distal aortic stent-graft prosthesis or module <NUM>, a first branch stent-graft prosthesis or module <NUM> extending from proximal aortic stent-graft prosthesis <NUM>, and a second branch stent-graft prosthesis or module <NUM> extending from distal aortic stent-graft prosthesis <NUM>. As will be explained in more detail, and as depicted in <FIG>, proximal aortic stent-graft prosthesis <NUM> is configured for placement within a proximal portion of the aorta arch, adjacent to or proximal to the brachiocephalic artery, while distal aortic stent-graft prosthesis <NUM> is configured for placement within a distal portion of the aorta arch, adjacent to or distal to the left subclavian artery. First branch stent-graft prosthesis <NUM> is configured for placement within the brachiocephalic artery, and is configured to extend from within the brachiocephalic artery to coupling <NUM> of proximal aortic stent-graft prosthesis <NUM> which is purposely positioned or configured to be positioned proximal to the ostium of the brachiocephalic artery. In the embodiment of <FIG>, a proximal portion of first branch stent-graft prosthesis <NUM> is configured for placement within the proximal portion of the aorta arch between an outer or exterior surface of proximal aortic stent-graft prosthesis <NUM> and the wall of the aorta. Second branch stent-graft prosthesis or module <NUM> is configured for placement in the left subclavian artery. The modular aspect of aortic arch prosthetic assembly <NUM> allows the interventionalist to treat each great vessel independently of the orientation of other target branch vessels and therefore aortic arch prosthetic assembly <NUM> is capable of treating a wider range of patient anatomies. More particularly, each module of aortic arch prosthetic assembly <NUM> is delivered independently of each other and thus each module can be optimized to conform to patient specific anatomical differences. Since each module of aortic arch prosthetic assembly <NUM> is delivered and deployed independently, each module can be aligned independently of each other and thus will result in higher levels of patient applicability. Further, the advantage of the modular approach of aortic arch prosthetic assembly <NUM> is that the amount of sufficient overlap between the proximal and distal aortic stent-graft prostheses <NUM>, <NUM> can be adjusted as desired by varying or changing the amount of ostial displacement. Stated another way, the interventionalist may selectively move, adjust, or otherwise position proximal and/or distal aortic stent-graft prostheses <NUM>, <NUM> as desired in order to achieve a sufficient overlap between the proximal and distal aortic stent-graft prostheses <NUM>, <NUM>. Thus, the modular aspect allows for aortic arch prosthetic assembly <NUM> to treat a variety of patients with a customizable or individualized approach but in an "off-the shelf" manner, i.e., with modular devices that are not custom designed for a particular patient's anatomy.

More particularly, aortic arch prosthetic assembly <NUM> is configured such that first branch stent-graft prosthesis <NUM> reroutes or displaces the ostium of the brachiocephalic artery to the ascending aorta towards or in the direction towards aortic valve AV (labeled in <FIG>) so that distal aortic stent-graft prosthesis <NUM> can be deployed with a sufficient overlap <NUM> with respect to proximal aortic stent-graft prosthesis <NUM>. Modular adjacent components such as proximal aortic stent-graft prosthesis <NUM> and distal aortic stent-graft prosthesis <NUM> require sufficient overlap <NUM> ranging between <NUM> and <NUM> to avoid endoleaks. Due to the curvature of the aortic arch, the amount of sufficient overlap may vary based on whether the measurements are along the inner aortic curve, the outer aortic curve, or the centerline of the aortic curve. By purposely positioning coupling <NUM> of proximal aortic stent-graft prosthesis <NUM> to be proximal to the ostium of the brachiocephalic artery when deployed in situ, first branch stent-graft prosthesis <NUM> reroutes or displaces the ostium of the brachiocephalic artery to the ascending aorta. As such, aortic arch prosthetic assembly <NUM> provides for an endovascular approach that creates or widens the distance for a landing zone <NUM> for the deployment of distal aortic stent-graft prosthesis <NUM>. In this embodiment, landing zone <NUM> extends from the distal end of proximal aortic stent-graft prosthesis <NUM> to a proximal end of first branch stent-graft prosthesis <NUM> which extends through coupling <NUM> of proximal aortic stent-graft prosthesis <NUM>. When being deployed, the proximal end of distal aortic stent-graft prosthesis <NUM> may be disposed anywhere within landing zone <NUM> provided that an adequate or sufficient overlap occurs to create a seal between proximal and distal aortic stent-graft prostheses <NUM>, <NUM>. Once the proximal end of distal aortic stent-graft prosthesis <NUM> is disposed and deployed within the distal end of proximal aortic stent-graft prosthesis <NUM>, sufficient overlap <NUM> is created by the overlapping or overlaying portions of proximal and distal aortic stent-graft prostheses <NUM>, <NUM>. "Sufficient overlap" as used herein means that the overlapping or overlaying portions of proximal and distal aortic stent-graft prostheses <NUM>, <NUM> are of a length sufficient or adequate to avoid endoleaks. As previously stated herein, the advantage of the modular approach of aortic arch prosthetic assembly <NUM> is that the amount of sufficient overlap between the proximal and distal aortic stent-graft prostheses <NUM>, <NUM> can be adjusted as desired by varying or changing the amount of ostial displacement.

Another advantage of aortic arch prosthetic assembly <NUM> is that first branch stent-graft prosthesis <NUM> perfuses the brachiocephalic artery without impacting the proximal-most or seal stent of proximal aortic stent-graft prosthesis <NUM>. Unlike a chimney stent-graft, which is external to a main stent-graft entirely to the proximal end of the main stent-graft, first branch stent-graft prosthesis <NUM> extends external to proximal aortic stent-graft prosthesis <NUM> but does not extend to or reach the proximal-most or seal stent of proximal aortic stent-graft prosthesis <NUM>. Stated another way, as will be described in more detail herein, the proximal-most or seal stent of proximal aortic stent-graft prosthesis <NUM> is located proximal of the proximal end of first branch stent-graft prosthesis <NUM> and thus is not directly impacted by placement of first branch stent-graft prosthesis <NUM>. Having a proximal-most or seal stent that is independent of the ostium of the brachiocephalic artery (as defined by the proximal end of first branch stent-graft prosthesis <NUM>) has the added benefit of reducing the need for axial or rotational alignment of proximal aortic stent-graft prosthesis <NUM> which will lower the amount of manipulations required to deploy proximal aortic stent-graft prosthesis <NUM> and thus lower the risk for embolic stroke.

In the embodiment of <FIG>, first branch stent-graft prosthesis <NUM> provides perfusion to the brachiocephalic artery, second branch stent-graft prosthesis <NUM> provides perfusion to the left subclavian artery, and a bypass or transposition <NUM> provides perfusion to the left common carotid artery. Left common carotid artery to left subclavian artery bypass <NUM> may be performed as needed to maintain perfusion to all the arch branch vessels and is considered an easier, less invasive procedure than other bypass procedures.

<FIG> illustrate side views of proximal aortic stent-graft prosthesis <NUM>, distal aortic stent-graft prosthesis <NUM>, first branch stent-graft prosthesis <NUM>, and second branch stent-graft prosthesis <NUM>, respectively. Each module is shown in its deployed configuration and removed from aortic arch prosthetic assembly <NUM> for illustrative purposes, and each module will be described independently in turn. With reference to <FIG>, proximal aortic stent-graft prosthesis <NUM> is configured for placement in a proximal portion of the aorta arch, adjacent to the brachiocephalic artery, and/or into the ascending aorta proximal to the brachiocephalic artery. Proximal aortic stent-graft prosthesis <NUM> includes graft material <NUM> coupled to circumferential stents <NUM>. Graft material <NUM> may be coupled to circumferential stents <NUM> using stitching or other means. In the embodiment shown in <FIG>, circumferential stents <NUM> are coupled to an outside surface of graft material <NUM>. However, circumferential stents <NUM> may alternatively be coupled to an inside surface of graft material <NUM>. Although shown with five circumferential stents, it will be understood by one of ordinary skill in the art that proximal aortic stent-graft prosthesis <NUM> may include a greater or smaller number of stents depending upon the desired length of proximal aortic stent-graft prosthesis <NUM> and/or the intended application thereof. Graft material <NUM> may be any suitable graft material, for example and not limited to, woven polyester, DACRON® material, expanded polytetrafluoroethylene, polyurethane, silicone, electro spun materials, or other suitable materials. Circumferential stents <NUM> may be any conventional stent material or configuration. As shown, circumferential stents <NUM> are preferably made from a shape memory material, such as nickel-titanium alloy (nitinol), and are formed into a zig-zag configuration. The configuration of circumferential stents <NUM> is merely exemplary, and circumferential stents <NUM> may have any suitable configuration known in the art, including but not limiting to a continuous or non-continuous helical configuration. Proximal aortic stent-graft prosthesis <NUM> includes a proximal end <NUM> and a distal end <NUM>. The stent which is disposed at proximal end <NUM> is referred to herein as the proximal-most stent 110A and may be generally described as an anchor stent or a seal stent in the art. In an embodiment hereof, as shown in <FIG>, the proximal-most stent 110A extends outside of the graft material <NUM> in an open-web or uncovered configuration. Stent <NUM> which is disposed at distal end <NUM> is referred to herein as the distal-most stent 110B and may be generally described as an anchor stent or a seal stent in the art. The distal-most stent 110B extends only to the edge of the graft material <NUM> in a closed-web configuration as shown. In another embodiment hereof, the proximal-most stent 110A may extend only to the edge of the graft material <NUM> in a closed-web configuration and/or the distal-most stent 110B may extend outside of the graft material <NUM> in an open-web or uncovered configuration. Graft material <NUM> has a tubular configuration and as such defines a lumen <NUM> therethrough. Proximal aortic stent-graft prosthesis <NUM> further includes coupling <NUM>, described in detail below with respect to <FIG>. Proximal aortic stent-graft prosthesis <NUM> may be similar to the Medtronic, Inc. 's VALIANT MONA LSA® thoracic stent-graft, or other known stent-grafts.

With additional reference to <FIG>, coupling <NUM> is disposed on a midportion of proximal aortic stent-graft prosthesis <NUM> corresponding to an opening in graft material <NUM>. In the embodiment of <FIG>, as described above, coupling <NUM> is purposely positioned or configured to be positioned proximal to the ostium of the brachiocephalic artery when deployed in situ. For sake of illustration, coupling <NUM> is shown approximately in the middle of proximal aortic stent-graft prosthesis <NUM> but the location of coupling <NUM> may vary and coupling <NUM> may be disposed closer to proximal end <NUM> or may be disposed closer to distal end <NUM>. In addition, for sake of illustration, coupling <NUM> is shown extending radially away from an outer surface of graft material <NUM> and thus may be considered an external coupling. However, coupling <NUM> may also be inverted so as to extend radially inward from an inner surface of graft material <NUM> and thus may be considered an internal coupling. Further, coupling <NUM> may be initially deployed in a first configuration, i.e., as an external coupling or an internal coupling, and may be displaced during positioning of a branch stent-graft prosthesis therethrough. Coupling <NUM> is generally frustoconically shaped. Coupling <NUM> is formed from graft material having a base <NUM> and a top <NUM>. The graft material of coupling <NUM> is preferably the same type of graft material as graft material <NUM> and is preferably a continuation of graft material <NUM>, although the coupling can be a separate piece of graft material attached to graft material <NUM>. Although coupling <NUM> is described as generally frustoconical in shape, base <NUM> is preferably generally elliptical rather than circular. Base <NUM> may have, for example and not by way of limitation, a long axis of approximately <NUM>-<NUM> and a short axis of approximately <NUM>-<NUM>. Further, the height of coupling <NUM> may be approximately <NUM>-<NUM>. Further, since coupling <NUM> is configured to be used with first branch stent-graft prosthesis <NUM> which perfuses the brachiocephalic artery, the diameter of the top <NUM> may be approximately <NUM>-<NUM>.

A circumferential stent or annular support wireform <NUM> may be coupled to the graft material of coupling <NUM> around top <NUM>. For description purposes, <FIG> illustrates support wireform <NUM> removed from coupling <NUM>. Support wireform <NUM> may be formed from a tubular structure or wire <NUM> of a biocompatible resilient material such as nickel-titanium alloy (nitinol), MP35N spring wire, an acetal copolymer, or a polymeric material having shape memory characteristics. In another embodiment, support wireform <NUM> may be formed from a plastically deformable material. Further, in another embodiment, support wireform <NUM> may be laser cut. Support wireform <NUM> may be made from the same material as main body circumferential stents <NUM> or may be made from different material. For example, circumferential stents <NUM> may be balloon expandable and support wireform <NUM> may be self-expanding. Preferably, circumferential stents <NUM> and support wireform <NUM> are made from shape memory materials such as nitinol and are self-expanding. In various embodiments, wire <NUM> may be solid or hollow and have a circular cross-section. An inch corresponds to <NUM>. In an embodiment, wire <NUM> has a diameter between <NUM> inch and <NUM> inch, whereas circumferential stents <NUM> are generally about. <NUM> inch to. <NUM> inch in diameter. In one embodiment, the cross-section of wire <NUM> may be oval, square, rectangular, or any other suitable shape. As shown, wire <NUM> is shaped into a zig-zag or generally sinusoidal configuration having a plurality of opposing bends or crowns <NUM>, <NUM> connecting generally straight segments or struts <NUM> together, and a crimp <NUM> connecting or coupling the two ends of wire <NUM> to form circumferential support wireform <NUM>. Crowns <NUM> are disposed adjacent top <NUM> of coupling <NUM> and crowns <NUM> are disposed spaced from top <NUM>. Support wireform <NUM> is oriented such that a longitudinal axis of support wireform <NUM> is generally co-linear with the longitudinal axis of coupling <NUM>. In one embodiment, support wireform <NUM> includes eight crowns <NUM> and eight crowns <NUM> but it will be understood by those of ordinary skill in the art that the number of crowns is not limited. Support wireform <NUM> is coupled to coupling <NUM> using stitching or other means. Support wireform <NUM> may be coupled to an outside surface of coupling <NUM> to avoid the potential of metal-to-metal contact between support wireform <NUM> and circumferential stents <NUM> of proximal aortic stent-graft prosthesis <NUM> or support wireform <NUM> may alternatively be coupled to an inside surface of the graft material <NUM> of coupling <NUM>.

In the embodiment of <FIG>, support wireform <NUM> is generally frustoconically shaped. Crowns <NUM> of frustoconical support wireform <NUM> are symmetrically arranged in a circle having a first diameter D1 and crowns <NUM> of frustoconical support wireform <NUM> are arranged to be equally spaced around a circle having a second diameter D2 which is greater than diameter D1. Although support wireform <NUM> is described as generally frustoconical in shape, the base thereof may alternatively be elliptical rather than circular to more closely imitate the profile of coupling <NUM>. If the base of support wireform <NUM> is elliptical, crowns <NUM> of frustoconical support wireform <NUM> are arranged to be equally spaced around an oviod. The height H of support wireform <NUM>, referring to the vertical or longitudinal distance between crowns <NUM> and crowns <NUM>, may vary between <NUM>% and <NUM>% of the height of coupling <NUM>. For example, for a coupling having a height between <NUM> and <NUM>, the height of support wireform <NUM> may be in the range of <NUM> and <NUM>. In another embodiment shown in <FIG>, the support wireform may be generally cylindrical in shape rather than frustoconical. More specifically, a support wireform <NUM> includes crowns <NUM> that are symmetrically arranged in a circle having a diameter D and crowns <NUM> of cylindrical support wireform <NUM> are arranged to be equally spaced around a circle also having diameter D.

Due to shape and material, coupling <NUM> has significant flexibility because the top of the coupling <NUM> when deployed can move longitudinally relative to the longitudinal axis of coupling <NUM>. In particular, referring back to <FIG>, coupling <NUM> includes an unsupported portion <NUM> of graft material <NUM> extending below support wireform <NUM> to base <NUM>. Stated another way, coupling <NUM> is unsupported between crowns <NUM> and main proximal aortic stent-graft prosthesis <NUM>. Unsupported portion <NUM> of graft material <NUM> does not have any inherent ability to position top <NUM> of coupling <NUM> as desired. However, support wireform <NUM> imparts structural integrity to the top <NUM> of coupling <NUM> to properly orient the top of coupling <NUM> as desired. The flexibility of coupling <NUM> and in particularly the flexibility of unsupported portion <NUM> of graft material <NUM> allows for proximal aortic stent-graft prosthesis <NUM> to be rotationally offset up to and beyond <NUM> degrees without compromising flow through the branch stent-graft prosthesis to the target vessel. Accordingly, if proximal aortic stent-graft prosthesis <NUM> is not perfectly rotationally aligned with a branch vessel, coupling <NUM> can move or shift to cause top <NUM> to point towards the branch vessel. The mobility of coupling <NUM> thus reduces the requirement of precise targeting thereof while still allowing for perfusion of the branch vessel. Coupling <NUM> and variations thereof is further described in <CIT> to Bruszewski et al. , assigned to the same assignee as the present disclosure.

Turning now to <FIG>, distal aortic stent-graft prosthesis <NUM> is configured for placement in a distal portion of the aorta arch, adjacent to the left subclavian artery and/or. Similar to proximal aortic stent-graft prosthesis <NUM>, distal aortic stent-graft prosthesis <NUM> includes graft material <NUM> coupled to circumferential stents <NUM>. Graft material <NUM> may be coupled to circumferential stents <NUM> using stitching or other means. In the embodiment shown in <FIG>, circumferential stents <NUM> are coupled to an outside surface of graft material <NUM>. However, circumferential stents <NUM> may alternatively be coupled to an inside surface of graft material <NUM>. Although shown with four circumferential stents, it will be understood by one of ordinary skill in the art that distal aortic stent-graft prosthesis <NUM> may include a greater or smaller number of stents depending upon the desired length of distal aortic stent-graft prosthesis <NUM> and/or the intended application thereof. Graft material <NUM> may be any suitable graft material, for example and not limited to, woven polyester, DACRON® material, expanded polytetrafluoroethylene, polyurethane, silicone, or other suitable materials. Circumferential stents <NUM> may be any conventional stent material or configuration. As shown, circumferential stents <NUM> are preferably made from a shape memory material, such as nickel-titanium alloy (nitinol), and are formed into a zig-zag configuration. The configuration of circumferential stents <NUM> is merely exemplary, and circumferential stents <NUM> may have any suitable configuration known in the art, including but not limiting to a continuous or non-continuous helical configuration. Distal aortic stent-graft prosthesis <NUM> includes a proximal end <NUM> and a distal end <NUM>. In an embodiment hereof, as shown in <FIG>, both a proximal-most stent 130A and a distal-most stent 130B extend only to the edge of the graft material <NUM> in a closed-web configuration as shown. In another embodiment hereof, the proximal-most stent and/or distal-most stent may extend outside of the graft material <NUM> in an open-web or uncovered configuration. Graft material <NUM> has a tubular configuration and as such defines a lumen <NUM> therethrough. Distal aortic stent-graft prosthesis <NUM> further includes a coupling <NUM>. Distal aortic stent-graft prosthesis <NUM> may be similar to the Medtronic, Inc. 's VALIANT MONA LSA® thoracic stent-graft, or other known stent-grafts.

Coupling <NUM> is similar to coupling <NUM> in structure and is disposed on a midportion of distal aortic stent-graft prosthesis <NUM> corresponding to an opening in graft material <NUM>. For sake of illustration, coupling <NUM> is shown approximately in the middle of distal aortic stent-graft prosthesis <NUM> but the location of coupling <NUM> may vary and coupling <NUM> may be disposed closer to proximal end <NUM> or may be disposed closer to distal end <NUM>. In addition, for sake of illustration, coupling <NUM> is shown extending radially away from an outer surface of graft material <NUM> and thus may be considered an external coupling. However, coupling <NUM> may also be inverted so as to extend radially inward from an inner surface of graft material <NUM> and thus may be considered an internal coupling. Similar to coupling <NUM>, coupling <NUM> is generally frustoconically shaped and is formed from graft material having a base <NUM> and a top <NUM>. Coupling <NUM> has similar dimensions to coupling <NUM> except that since coupling <NUM> is configured to be used at the junction of the aorta and left common carotid artery or the junction of the aorta and left subclavian artery, the diameter of the top <NUM> may be approximately <NUM>-<NUM>. Similar to wireform <NUM>, a circumferential stent or annular support wireform <NUM> may be coupled to the graft material of coupling <NUM> around top <NUM>.

Turning now to <FIG>, first branch stent-graft prosthesis <NUM> is configured for placement in a vessel such as the brachiocephalic artery. First branch stent-graft prosthesis <NUM> includes graft material <NUM> coupled to circumferential stents <NUM>. Graft material <NUM> may be coupled to circumferential stents <NUM> using stitching or other means. In the embodiment shown in <FIG>, circumferential stents <NUM> are coupled to an outside surface of graft material <NUM>. However, circumferential stents <NUM> may alternatively be coupled to an inside surface of graft material <NUM>. Although shown with seven circumferential stents, it will be understood by one of ordinary skill in the art that first branch stent-graft prosthesis <NUM> may include a greater or smaller number of stents depending upon the desired length of first branch stent-graft prosthesis <NUM> and/or the intended application thereof. Graft material <NUM> may be any suitable graft material, for example and not limited to, woven polyester, DACRON® material, expanded polytetrafluoroethylene, polyurethane, silicone, or other suitable materials. Circumferential stents <NUM> may be any conventional stent material or configuration. As shown, circumferential stents <NUM> are preferably made from a shape memory material, such as nickel-titanium alloy (nitinol), and are formed into a zig-zag configuration. The configuration of circumferential stents <NUM> is merely exemplary, and circumferential stents <NUM> may have any suitable configuration known in the art, including but not limiting to a continuous or non-continuous helical configuration. First branch stent-graft prosthesis <NUM> includes a proximal end <NUM> and a distal end <NUM>. In an embodiment hereof, as shown in <FIG>, both a proximal-most stent 150A and a distal-most stent 150B extend only to the edge of the graft material <NUM> in a closed-web configuration as shown. In another embodiment hereof, the proximal-most stent and/or distal-most stent may extend outside of the graft material <NUM> in an open-web or uncovered configuration. Graft material <NUM> has a tubular configuration and as such defines a lumen <NUM> therethrough. First branch stent-graft prosthesis <NUM> may be similar to the Medtronic, Inc. 's VALIANT® thoracic stent-graft, or other known stent-grafts.

First branch stent-graft prosthesis <NUM> is configured to exert a higher radial force than the radial force of proximal aortic stent-graft prosthesis <NUM> and/or distal aortic stent-graft prosthesis <NUM>. As used herein, "radial force" includes both a radial force exerted during expansion/deployment as well as a chronic radial force continuously exerted after implantation such that a scaffold has a predetermined compliance or resistance as the surrounding native anatomy, i.e., the ascending aorta or the native valve annulus, expands and contracts during the cardiac cycle. The radial force of proximal aortic stent-graft prosthesis <NUM> and/or distal aortic stent-graft prosthesis <NUM> is configured to be lower than that of first branch stent-graft prosthesis <NUM> in order to avoid collapse of first branch stent-graft prosthesis <NUM> when proximal aortic stent-graft prosthesis <NUM> and/or distal aortic stent-graft prosthesis <NUM> are deployed against and adjacent thereof and thus maintain perfusion of the brachiocephalic artery. In order to configure the stent-graft prostheses with differing relative radial forces, stents <NUM> of first branch stent-graft prosthesis <NUM> may be constructed with relatively thicker and/or shorter segments of material than stents <NUM> of distal aortic stent-graft prosthesis <NUM> and/or stents <NUM> of proximal aortic stent-graft prosthesis <NUM>. Conversely, stents <NUM>, <NUM> of proximal aortic stent-graft prosthesis <NUM> and/or distal aortic stent-graft prosthesis <NUM>, respectively, may be constructed with relatively thinner and/or longer segments of material than stents <NUM> of first branch stent-graft prosthesis <NUM>. Shorter and/or thicker scaffold segments have less flexibility but greater radial force to ensure that stents <NUM>, <NUM> of proximal aortic stent-graft prosthesis <NUM> and distal aortic stent-graft prosthesis <NUM>, respectively, do not collapse lumen <NUM> of first branch stent-graft prosthesis <NUM>. Other variations or modification of the stents/scaffolds may be used to configure the stents/scaffolds with differing relative radial forces without departing from the scope of the present invention.

With reference to <FIG>, second branch stent-graft prosthesis <NUM> is configured for placement in a vessel such as the left common carotid artery or the left subclavian artery. Second branch stent-graft prosthesis <NUM> includes graft material <NUM> coupled to circumferential stents <NUM>. Graft material <NUM> may be coupled to circumferential stents <NUM> using stitching or other means. In the embodiment shown in <FIG>, circumferential stents <NUM> are coupled to an outside surface of graft material <NUM>. However, circumferential stents <NUM> may alternatively be coupled to an inside surface of graft material <NUM>. Although shown with five circumferential stents, it will be understood by one of ordinary skill in the art that second branch stent-graft prosthesis <NUM> may include a greater or smaller number of stents depending upon the desired length of second branch stent-graft prosthesis <NUM> and/or the intended application thereof. Graft material <NUM> may be any suitable graft material, for example and not limited to, woven polyester, DACRON® material, expanded polytetrafluoroethylene, polyurethane, silicone, or other suitable materials. Circumferential stents <NUM> may be any conventional stent material or configuration. As shown, circumferential stents <NUM> are preferably made from a shape memory material, such as nickel-titanium alloy (nitinol), and are formed into a zig-zag configuration. The configuration of circumferential stents <NUM> is merely exemplary, and circumferential stents <NUM> may have any suitable configuration known in the art, including but not limiting to a continuous or non-continuous helical configuration. Second branch stent-graft prosthesis <NUM> includes a proximal end <NUM> and a distal end <NUM>. In an embodiment hereof, as shown in <FIG>, both a proximal-most stent 160A and a distal-most stent 160B extend only to the edge of the graft material <NUM> in a closed-web configuration as shown. In another embodiment hereof, the proximal-most stent and/or distal-most stent may extend outside of the graft material <NUM> in an open-web or uncovered configuration. Further, as shown in <FIG>, in an embodiment hereof proximal end <NUM> of second branch stent-graft prosthesis <NUM> is flared. The flared proximal end <NUM> aids in sealing of second branch stent-graft prosthesis <NUM> by matching the flare thereof with the taper of the outer surface of coupling <NUM> of distal aortic stent-graft prosthesis <NUM>. Graft material <NUM> has a tubular configuration and as such defines a lumen <NUM> therethrough. Second branch stent-graft prosthesis <NUM> may be similar to the Medtronic, Inc. 's VALIANT® thoracic stent-graft, or other known stent-grafts.

Although not shown, in another embodiment hereof, proximal end <NUM> of first branch stent-graft prosthesis <NUM> may also be flared similar to proximal end <NUM> of second branch stent-graft prosthesis <NUM> to aid in sealing between first branch stent-graft prosthesis <NUM> and coupling <NUM> of proximal aortic stent-graft prosthesis <NUM>.

As will be explained in more detail herein, first and second branch stent-graft prostheses <NUM>, <NUM> are delivered and deployed through couplings <NUM>, <NUM> of proximal and distal aortic stent-graft prostheses <NUM>, <NUM>, respectively. After implantation, pulsatile expansion and/or other movement of the branch vessel may occur during the cardiac cycle. Such movement of the branch vessel may eventually degrade the seal between couplings <NUM>, <NUM> of proximal and distal aortic stent-graft prostheses <NUM>, <NUM>, respectively, due to deformation of the material of the branch vessel prosthesis. More particularly, referring now to <FIG>, a schematic illustration of coupling <NUM> including support wireform <NUM> with first branch stent-graft prosthesis <NUM> deployed therein is shown. Support wireform <NUM> produces an interference seal between first branch stent-graft prosthesis <NUM> and coupling <NUM>. Support wireform <NUM> enhances sealing between first branch stent-graft prosthesis <NUM> and coupling <NUM> because first branch stent-graft prosthesis <NUM> expands or deploys within coupling <NUM> to abut against support wireform <NUM>, the result being that support wireform <NUM> securely fits around a proximal portion of first branch stent-graft prosthesis <NUM>.

In one embodiment, the deployed diameter of support wireform <NUM> may be undersized or smaller than the deployed diameter of first branch stent-graft prosthesis <NUM> to provide a more effective seal between coupling <NUM> and first branch stent-graft prosthesis <NUM>. More particularly, the deployed diameter of support wireform <NUM> may be up to approximately <NUM>% smaller than the deployed diameter of first branch stent-graft prosthesis <NUM>. Deployment of first branch stent-graft prosthesis <NUM> into coupling <NUM> results in expansion of branch prosthesis <NUM> to the limiting diameter of support wireform <NUM>. Thus, even if movement of first branch stent-graft prosthesis <NUM> occurs after implantation, the shape memory of undersized support wireform <NUM> urges coupling <NUM> to the shape memory diameter of support wireform <NUM> to thereby compensate for the movement and retain the seal between coupling <NUM> and first branch stent-graft prosthesis <NUM>. Undersized support wireform <NUM> and first branch stent-graft prosthesis <NUM> are two elastic pieces exerting opposing forces onto each other. In other words, because branch prosthesis <NUM> wants to expand to a larger diameter than the limiting diameter of support wireform <NUM>, branch prosthesis <NUM> provides an outward force and support wireform <NUM> provides a counteracting inward force to maintain the seal between coupling <NUM> and branch prosthesis <NUM>.

In the embodiment of <FIG>, the scaffolding or support structure of first and second branch stent-graft prostheses <NUM>, <NUM> has been illustrated as a series of independent or separate self-expanding stents/sinusoidal patterned rings. However, the support structure or scaffolding of first and second branch stent-graft prostheses <NUM>, <NUM> may have other configurations such as a series of sinusoidal patterned rings coupled to each other to form a self-expanding stent or a unitary tubular radiallycompressible scaffold.

<CIT> to Bruszewski et al. , assigned to the same assignee as the present disclosure, describes one or more examples of a delivery system that can be used to deliver each module of aortic arch prosthetic assembly <NUM> to the target location within a vessel and many other delivery systems known to those skilled in the art could be utilized. For example, each module of aortic arch prosthetic assembly <NUM> could be mounted onto a balloon to be expanded when at the target site. Thus, stated another way, one or more modules may be balloon-expandable rather than self-expanding. Further, it may be desirable to utilize a combination of balloon-expandable modules and self-expanding modules. Other stent-graft-delivery systems, for example and not by way of limitation, the delivery systems described in <CIT> and <CIT> and <CIT>, and <CIT> and <CIT>, may be utilized to deliver and deploy each module of aortic arch prosthetic assembly <NUM>.

<FIG> schematically show a method of delivering and deploying aortic arch prosthetic assembly <NUM> within the aortic arch. In the example described herein, the aortic arch prosthetic assembly <NUM> is delivered and deployed into the aortic arch. Portions of the aorta include the ascending aorta, the aortic arch (labeled as "AA" in the figures), and the descending aorta. Branching from the aortic arch are the brachiocephalic artery BCA, the left common carotid LCC artery, and the left subclavian artery LSA. An aneurysm (not shown) may form in any area of the aortic arch, and can be difficult to bypass or exclude with a single stent-graft because blood flow to the branch arteries must be maintained. As previously stated, although the description of embodiments hereof is primarily in the context of modular devices for treating aneurysm disease within an aortic arch, the modular devices described herein can also be used to treat other aortic arch pathologies including but not limited to dissections, penetrating ulcers, intramural hematomas, transections, and pseudoaneurysms.

Prior to the procedure for inserting aortic arch prosthetic assembly <NUM>, a surgical by-pass procedure installing bypass <NUM> is performed to connect the left common carotid LCC artery to the left subclavian artery LSA. Such surgical bypass procedures may be performed one to two weeks prior to insertion of aortic arch prosthetic assembly <NUM>, or may be performed at the same time as the implantation procedure for aortic arch prosthetic assembly <NUM>, and present significantly less complications and risk than a surgical solution to repair an aneurysm in the aortic arch. In this manner, maintaining perfusion to one of the left subclavian artery LSA or the left common carotid LCC artery will simultaneously maintain perfusion to the other branch artery.

<FIG> shows a first guidewire GW1 and a second guidewire GW2 advanced through the descending aorta, through the aortic arch, and into the ascending aorta. Guidewires GW1, GW2 are typically inserted into the femoral artery and routed up through the abdominal aorta, and into the thoracic aorta, as is known in the art. In another embodiment hereof (not shown), guidewires GW1, GW2 can be introduced via supra aortic or transapical access.

<FIG> shows a stent-graft delivery system <NUM>, with proximal aortic stent-graft prosthesis <NUM> compressed therein, advanced over guidewires GW1, GW2 to the target location in the aortic arch. The location of the stent-graft delivery system <NUM> and/or the proximal aortic stent-graft prosthesis <NUM> may be verified radiographically and delivery system <NUM> and/or proximal aortic stent-graft prosthesis <NUM> may include radiopaque markers as known in the art. Second guidewire GW2 may also be locked at its distal or superaortic end so as to prevent second guidewire GW2 from retracting. More particularly, the distal end of second guidewire GW2 may be captured with a snare (not shown) and pulled through the brachiocephalic artery BCA as shown in <FIG>. The distal end of second guidewire GW2 is pulled until second guidewire GW2 extends from a brachial entry point through the aorta and out at the femoral arteriotomy site, as is known to those of ordinary skill in the art as a through-and-through wire technique. The through-and-through access improves the ability to stabilize and manipulate second guidewire GW2 during the procedure. In addition, the through-and-through wire technique reduces the complexity of branch stent-graft deployment to the branch vessels in the case of axial or rotational misalignment or patient specific anatomical variation.

After stent-graft delivery system <NUM> is in the location where the coupling <NUM> of proximal aortic stent-graft prosthesis <NUM> is disposed proximal to the opening into the brachiocephalic artery BCA (i.e., the ostium of the brachiocephalic artery BCA), an outer sleeve or sheath of stent-graft delivery system <NUM> is retracted proximally to deploy proximal aortic stent-graft prosthesis <NUM>. <FIG> illustrates proximal aortic stent-graft prosthesis <NUM> deployed within the aorta, with coupling <NUM> disposed proximal to the ostium of the brachiocephalic artery BCA. More particularly, the outer sleeve or sheath of stent-graft delivery system <NUM> may initially be retracted proximally to a position adjacent to coupling <NUM> to initially only release coupling <NUM>. When coupling <NUM> extends radially away from an outer surface of graft material <NUM> as an external coupling, coupling <NUM> including support wireform <NUM> provides structural integrity to the top of coupling <NUM>, and orients the distal end of the coupling radially outwards or towards the vessel wall of the aorta. Once coupling <NUM> is deployed, the outer sleeve or sheath of stent-graft delivery system <NUM> may be further retracted to deploy the remaining length of proximal aortic stent-graft prosthesis <NUM>. Once coupling <NUM> and proximal aortic stent-graft prosthesis <NUM> are deployed, delivery system <NUM> may be removed leaving proximal aortic stent-graft prosthesis <NUM> deployed in situ as shown in <FIG> with first and second guidewires GW1, GW2 disposed therethrough. In this embodiment, first guidewire GW1 is left in place for subsequent delivery of distal aortic stent-graft prosthesis <NUM> thereover to minimize the number of manipulations but in another embodiment hereof first guidewire GW1 may be removed and a different guidewire may be positioned for delivery of distal aortic stent-graft prosthesis <NUM>.

<FIG> shows a branch stent-graft delivery system <NUM>, with first branch stent-graft prosthesis <NUM> compressed therein, advanced over second guidewire GW2 to the target location in the brachiocephalic artery BCA and the ascending aorta. The location of the branch stent-graft delivery system <NUM> and/or the first branch stent-graft prosthesis <NUM> compressed therein may be verified radiographically and delivery system <NUM> and/or first branch stent-graft prosthesis <NUM> may include radiopaque markers as known in the art. Branch stent-graft delivery system <NUM> may be conventional and contains first branch stent-graft prosthesis <NUM> therein. In the embodiment of <FIG>, branch stent-graft delivery system <NUM> is advanced into the brachiocephalic artery BCA via the brachial entry point of second guidewire GW2. In another embodiment hereof depicted in <FIG>, branch stent-graft delivery system <NUM> with first branch stent-graft prosthesis <NUM> compressed therein is delivered into the brachiocephalic artery BCA via the femoral entry point of second guidewire GW2.

Regardless of which entry point of second guidewire GW2 is utilized, first branch stent-graft prosthesis <NUM> is advanced over second guidewire GW2 until it is positioned within the brachiocephalic artery BCA as desired with proximal end <NUM> of first branch stent-graft prosthesis <NUM> internal to proximal aortic stent-graft prosthesis <NUM>. Once first branch stent-graft prosthesis <NUM> is positioned as desired, an outer sheath of branch stent-graft delivery system <NUM> constraining first branch stent-graft prosthesis <NUM> is then retracted proximally, thereby releasing first branch stent-graft prosthesis <NUM> from the delivery system. Branch stent-graft delivery system <NUM> is then removed leaving first branch stent-graft prosthesis <NUM> deployed in situ as shown in <FIG>. As shown in <FIG>, second guidewire GW2 may also be removed at this point in the method while first guidewire GW1 still remains in place for subsequent delivery of distal aortic stent-graft prosthesis <NUM> thereover. When deployed, first branch stent-graft prosthesis <NUM> extends within the brachiocephalic artery BCA and through coupling <NUM> such that proximal end <NUM> of first branch stent-graft prosthesis <NUM> is disposed internal to proximal aortic stent-graft prosthesis <NUM>. Between the ostium/opening of the brachiocephalic artery BCA and coupling <NUM>, first branch stent-graft prosthesis <NUM> extends within the aorta and is external to proximal aortic stent-graft prosthesis <NUM>. Stated another way, a portion of first branch stent-graft prosthesis <NUM> is disposed outside of proximal aortic stent-graft prosthesis <NUM> and is sandwiched between and contacts both the outer surface of proximal aortic stent-graft prosthesis <NUM> and the wall of the aorta. If the aorta is aneurysmal, then first branch stent-graft prosthesis <NUM> may not be opposed against the outer surface of proximal aortic stent-graft prosthesis <NUM> and the wall of the aorta. Proximal end <NUM> of first branch stent-graft prosthesis <NUM> extends through coupling <NUM> and may be disposed within the lumen of proximal aortic stent-graft prosthesis <NUM>. In an embodiment hereof, approximately <NUM> of first branch stent-graft prosthesis <NUM> extends within the lumen of proximal aortic stent-graft prosthesis <NUM>. As shown on <FIG>, proximal end <NUM> of first branch stent-graft prosthesis <NUM> does not extend to or reach the proximal-most stent 110A of proximal aortic stent-graft prosthesis <NUM>. Stated another way, the proximal-most stent 110A of proximal aortic stent-graft prosthesis <NUM> is positioned proximal of the proximal end <NUM> of first branch stent-graft prosthesis <NUM>. First branch stent-graft prosthesis <NUM> proximally reroutes or displaces the ostium of the brachiocephalic artery BCA which is now defined by proximal end <NUM> of first branch stent-graft prosthesis <NUM> to the ascending aorta.

With a portion of first branch stent-graft prosthesis <NUM> being disposed outside of or external to proximal aortic stent-graft prosthesis <NUM>, proximal aortic stent-graft prosthesis <NUM> contacts or abuts against an outer surface of deployed first branch stent-graft prosthesis <NUM>. However, since first branch stent-graft prosthesis <NUM> has a higher radial force than proximal aortic stent-graft prosthesis <NUM> as described herein, proximal aortic stent-graft prosthesis <NUM> does not collapse or otherwise interfere with deployed first branch stent-graft prosthesis <NUM> and perfusion of the brachiocephalic artery BCA provided thereby. Proximal aortic stent-graft prosthesis <NUM> may be partially collapsed by deployed first branch stent-graft prosthesis <NUM>, but lumen <NUM> remains at least partially open for blood to flow through proximal aortic stent-graft prosthesis <NUM> due to the relatively smaller size of deployed first branch stent-graft prosthesis <NUM>.

<FIG> shows a third guidewire GW3 advanced through the descending aorta, and into the aortic arch. Third guidewires GW3 is typically inserted into the femoral artery and routed up through the abdominal aorta, and into the thoracic aorta, as is known in the art. In another embodiment hereof (not shown), second guidewire GW2 may not be previously removed but rather may be repositioned as third guidewire GW3.

<FIG> shows a stent-graft delivery system <NUM>, with distal aortic stent-graft prosthesis <NUM> compressed therein, advanced over first and third guidewires GW1, GW3 to the target location in the aortic arch. The location of stent-graft delivery system <NUM> and/or distal aortic stent-graft prosthesis <NUM> may be verified radiographically and delivery system <NUM> and/or distal aortic stent-graft prosthesis <NUM> may include radiopaque markers as known in the art. Third guidewire GW3 may also be locked at its distal or superaortic end so as to prevent third guidewire GW3 from retracting. More particularly, the distal end of third guidewire GW3 may be captured with a snare (not shown) and pulled through the left subclavian artery LSA as shown in <FIG>. The distal end of third guidewire GW3 is pulled until third guidewire GW3 extends from a radial artery entry point through the aorta and out at the femoral arteriotomy site, as is known to those of ordinary skill in the art as a through-and-through wire technique. The through-and-through access improves the ability to stabilize and manipulate third guidewire GW3 during the procedure. In addition, the through-and-through wire technique reduces the complexity of branch stent-graft deployment to the branch vessels in the case of axial or rotational misalignment or patient specific anatomical variation.

After stent-graft delivery system <NUM> is in the location where the coupling <NUM> of distal aortic stent-graft prosthesis <NUM> is approximately aligned with the opening into the left subclavian artery LSA, an outer sleeve or sheath of stent-graft delivery system <NUM> is retracted proximally to deploy distal aortic stent-graft prosthesis <NUM> as shown in <FIG>. More particularly, the outer sleeve or sheath of stent-graft delivery system <NUM> may initially be retracted proximally to a position adjacent to coupling <NUM> to initially only release coupling <NUM>. When coupling <NUM> extends radially away from an outer surface of graft material <NUM> as an external coupling, coupling <NUM> including support wireform <NUM> provides structural integrity to the top of coupling <NUM>, and orients the distal end of the coupling towards and/or into the ostium of the left subclavian artery LSA. Delivery system <NUM> may then be moved and/or rotated to better align coupling <NUM> with the left subclavian artery LSA. Further, due to the configuration of coupling <NUM>, even if it is not perfectly aligned with the left subclavian artery LSA, the top of the coupling <NUM> may be moved to properly align its lumen opening with the lumen of the left subclavian artery LSA without having to move the entire distal aortic stent-graft prosthesis <NUM>. Once coupling <NUM> is deployed and in position in or adjacent to the left subclavian artery LSA, the outer sleeve or sheath of stent-graft delivery system <NUM> may be further retracted to deploy the remaining length of distal aortic stent-graft prosthesis <NUM>. Once coupling <NUM> and distal aortic stent-graft prosthesis <NUM> are deployed, delivery system <NUM> may be removed leaving distal aortic stent-graft prosthesis <NUM> deployed in situ as shown in <FIG>. If desired, first guidewire GW1 may be removed at this point of the procedure.

With first branch stent-graft prosthesis <NUM> proximally rerouting or displacing the ostium of the brachiocephalic artery BCA to the ascending aorta as described above, distal aortic stent-graft prosthesis <NUM> is deployed with sufficient overlap <NUM> with respect to proximal aortic stent-graft prosthesis <NUM>. Proximal end <NUM> of distal aortic stent-graft prosthesis <NUM> is thus disposed proximal to distal end <NUM> of proximal aortic stent-graft prosthesis <NUM>, and proximal and distal aortic stent-graft prostheses <NUM>, <NUM> overlay each other for a portion thereof, thereby forming sufficient overlap <NUM> to avoid and/or minimize endoleaks between the modular components. Although shown with proximal end <NUM> of distal aortic stent-graft prosthesis <NUM> disposed distal to coupling <NUM> and first branch stent-graft prosthesis <NUM>, proximal end <NUM> of distal aortic stent-graft prosthesis <NUM> may be deployed up to proximal end <NUM> of first branch stent-graft prosthesis <NUM>. Stated another way, proximal end <NUM> of distal aortic stent-graft prosthesis <NUM> may be more proximally disposed than shown to increase the amount of sufficient overlap <NUM> but cannot occlude or block proximal end <NUM> of first branch stent-graft prosthesis <NUM> which is providing profusion to the brachiocephalic artery BCA. In such a case, proximal end <NUM> of distal aortic stent-graft prosthesis <NUM> may abut against or contact an outer surface of deployed first branch stent-graft prosthesis <NUM> that is extending internal to proximal aortic stent-graft prosthesis <NUM>. However, since first branch stent-graft prosthesis <NUM> has a higher radial force than distal aortic stent-graft prosthesis <NUM> as described herein, distal aortic stent-graft prosthesis <NUM> does not collapse or otherwise interfere with deployed first branch stent-graft prosthesis <NUM> and perfusion of the brachiocephalic artery BCA provided thereby.

Notably, when first branch stent-graft prosthesis <NUM>, proximal aortic stent-graft prosthesis <NUM>, and distal aortic stent-graft prosthesis <NUM> are deployed as shown in <FIG>, a portion <NUM> of the first branch stent-graft prosthesis (in its expanded configuration) extends along sufficient overlap <NUM> such that proximal end <NUM> of first branch stent-graft prosthesis <NUM> is positioned proximal to sufficient overlap <NUM> and effectively proximally reroutes the ostium of the brachiocephalic artery BCA. Stated another way, at a cross-section of the deployed aortic arch prosthetic assembly <NUM> taken within portion <NUM>, the cross-section includes first branch stent-graft prosthesis <NUM>, proximal aortic stent-graft prosthesis <NUM>, and distal aortic stent-graft prosthesis <NUM>. In this embodiment, first branch stent-graft prosthesis <NUM> extends external to or outside of proximal aortic stent-graft prosthesis <NUM> (i.e., portion <NUM> of first branch stent-graft prosthesis <NUM> extends between an outer surface of proximal aortic stent-graft prosthesis <NUM> and a vessel wall of the aortic arch) and thus first branch stent-graft prosthesis <NUM> abuts against concentrically disposed proximal and distal aortic stent-graft prostheses <NUM>, <NUM> along portion <NUM>. As previously described, however, first branch stent-graft prosthesis <NUM> is configured to exert a higher radial force than proximal aortic stent-graft prosthesis <NUM> such that first branch stent-graft prosthesis <NUM> does not collapse due to the contact with proximal aortic stent-graft prosthesis <NUM>.

<FIG> shows a branch stent-graft delivery system <NUM>, with second branch stent-graft prosthesis <NUM> compressed therein, advanced over third guidewire GW3 to the target location in the left subclavian artery LSA and into the descending aorta. The location of the branch stent-graft delivery system <NUM> and/or second branch stent-graft prosthesis <NUM> compressed therein may be verified radiographically and delivery system <NUM> and/or second branch stent-graft prosthesis <NUM> may include radiopaque markers as known in the art. Branch stent-graft delivery system <NUM> may be conventional and contains therein second branch stent-graft prosthesis <NUM>. Branch stent-graft delivery system <NUM> is advanced into the left subclavian artery LSA such that proximal end <NUM> of second branch stent-graft prosthesis <NUM> is disposed within coupling <NUM>. In the embodiment of <FIG>, branch stent-graft delivery system <NUM> is advanced into the left subclavian artery LSA via the radial artery entry point of third guidewire GW3. In another embodiment hereof depicted in <FIG>, branch stent-graft delivery system <NUM> with second branch stent-graft prosthesis <NUM> compressed therein is delivered into the left subclavian artery LSA via the femoral entry point of third guidewire GW3.

Regardless of which entry point of third guidewire GW3 is utilized, second branch stent-graft prosthesis <NUM> is advanced over third guidewire GW3 until it is positioned within the left subclavian artery LSA as desired with proximal end <NUM> of second branch stent-graft prosthesis <NUM> disposed within coupling <NUM> of distal aortic stent-graft prosthesis <NUM>. Once second branch stent-graft prosthesis <NUM> is positioned as desired, an outer sheath of branch stent-graft delivery system <NUM> constraining second branch stent-graft prosthesis <NUM> is then retracted proximally, thereby releasing second branch stent-graft prosthesis <NUM> from the delivery system. Branch stent-graft delivery system <NUM> and third guidewire GW3 are then removed leaving second branch stent-graft prosthesis <NUM> deployed in situ as shown in <FIG>. Second branch stent-graft prosthesis <NUM> now perfuses the left subclavian artery LSA. Although the opening (or ostium) to the left common carotid LCC artery directly from the aortic arch is blocked by aortic arch prosthetic assembly <NUM>, bypass <NUM> fluidly connects the left common carotid LCC artery to the left subclavian artery LSA and thus perfusion of the left subclavian artery LSA also provides perfusion to the left common carotid LCC artery. Thus, all the great vessels branching off the aortic arch are perfused.

<FIG> illustrates an alternative embodiment hereof in which the ostium of the left subclavian artery LSA is displaced distally by the second branch stent-graft prosthesis in a manner similar to the way the ostium of the brachiocephalic artery BCA is displaced proximally by the first branch stent-graft prosthesis. The ostium of the left subclavian artery LSA is displaced distally to further increase the amount of achievable overlap of the modular components. An aortic arch prosthetic assembly <NUM> is shown deployed and assembled in situ within an aortic arch in <FIG>. Aortic arch prosthetic assembly <NUM> includes a proximal aortic stent-graft prosthesis or module <NUM> which is similar to proximal aortic stent-graft prosthesis or module <NUM>, a distal aortic stent-graft prosthesis or module <NUM> which is similar to distal aortic stent-graft prosthesis or module <NUM>, a first branch stent-graft prosthesis or module <NUM> which is similar to first branch stent-graft prosthesis or module <NUM>, and a second branch stent-graft prosthesis or module <NUM>. Similar to coupling <NUM>, a coupling <NUM> of first or proximal aortic stent-graft prosthesis or module <NUM> is purposely positioned or configured to be positioned proximal to the ostium of the brachiocephalic artery. In addition, distal aortic stent-graft prosthesis or module <NUM> is similar to distal aortic stent-graft prosthesis or module <NUM> except that a coupling <NUM> thereof is purposely positioned or configured to be positioned in situ distal to the ostium of the left subclavian artery LSA. By purposely positioning coupling <NUM> of distal aortic stent-graft prosthesis <NUM> to be distal to the ostium of the left subclavian artery LSA when deployed in situ, second branch stent-graft prosthesis <NUM> reroutes or displaces the ostium of the left subclavian artery LSA to the descending aorta.

More particularly, aortic arch prosthetic assembly <NUM> is configured such that first branch stent-graft prosthesis <NUM> proximally reroutes or displaces the ostium of the brachiocephalic artery to the ascending aorta and second branch stent-graft prosthesis <NUM> distally reroutes or displaces the ostium of the left subclavian artery LSA to the descending aorta so that distal aortic stent-graft prosthesis <NUM> can be deployed with a sufficient overlap <NUM> with respect to proximal aortic stent-graft prosthesis <NUM>. By rerouting or displacing the ostium of the brachiocephalic artery BCA as well as the ostium of the left subclavian artery LSA, aortic arch prosthetic assembly <NUM> provides for an endovascular approach that creates or widens the distance for a landing zone <NUM> for the deployment of distal aortic stent-graft prosthesis <NUM>. Landing zone <NUM> is greater than landing zone <NUM> described and shown above with respect to <FIG> since landing zone <NUM> includes the additional distance gained from distally rerouting or displacing the ostium of the left subclavian artery LSA via second branch stent-graft prosthesis <NUM>. Landing zone <NUM> extends from the proximal end of first branch stent-graft prosthesis <NUM> (which is disposed after rerouting thereof in the ascending aorta) to proximal end <NUM> of second branch stent-graft prosthesis <NUM> (which is disposed after rerouting thereof in the descending aorta).

<FIG> illustrates an alternative embodiment hereof in which the ostium of the brachiocephalic artery BCA is displaced proximally by the first branch stent-graft prosthesis. In previously-described embodiments, at least a portion of the first branch stent-graft prosthesis (first branch stent-graft prosthesis <NUM>) extends external to or outside of the proximal aortic stent-graft prosthesis (proximal aortic stent-graft prosthesis <NUM>) such that this external portion of the first branch stent-graft prosthesis is sandwiched between and contacts both the outer surface of the proximal aortic stent-graft prosthesis and the wall of the aorta. However, in the embodiment of <FIG>, the first branch stent-graft prosthesis extends only internal to or inside of the proximal aortic stent-graft prosthesis. Stated another way, in the embodiment of <FIG>, no portion of the first branch stent-graft prosthesis is sandwiched between the outer surface of the proximal aortic stent-graft prosthesis and the wall of the aorta. An aortic arch prosthetic assembly <NUM> is shown deployed and assembled in situ within an aortic arch in <FIG>. Aortic arch prosthetic assembly <NUM> includes a proximal aortic stent-graft prosthesis or module <NUM> which is similar to proximal aortic stent-graft prosthesis or module <NUM>, distal aortic stent-graft prosthesis or module <NUM>, a first branch stent-graft prosthesis or module <NUM> which is similar to first branch stent-graft prosthesis or module <NUM>, and second branch stent-graft prosthesis or module <NUM>. In this embodiment, a coupling <NUM> of proximal aortic stent-graft prosthesis <NUM> is not purposely positioned or configured to be positioned proximal to the ostium of the brachiocephalic artery. Rather, coupling <NUM> is positioned or configured to extend into the ostium of the brachiocephalic artery as shown in <FIG>. First branch stent-graft prosthesis <NUM> is then deployed through coupling <NUM> but a relatively longer portion of first branch stent-graft prosthesis <NUM> extends within the lumen of proximal aortic stent-graft prosthesis <NUM>. For example, in an embodiment hereof, approximately <NUM>-<NUM> of first branch stent-graft prosthesis <NUM> extends within the lumen of proximal aortic stent-graft prosthesis <NUM>. Distal aortic stent-graft prosthesis <NUM> is then deployed within the distal portion of proximal aortic stent-graft prosthesis <NUM>. When deployed, distal aortic stent-graft prosthesis <NUM> contacts or abuts against the outer surface of a portion of deployed first branch stent-graft prosthesis <NUM>. However, first branch stent-graft prosthesis <NUM> has a higher radial force than distal aortic stent-graft prosthesis <NUM> and thus distal aortic stent-graft prosthesis <NUM> does not collapse or otherwise interfere with deployed first branch stent-graft prosthesis <NUM> and perfusion of the brachiocephalic artery BCA provided thereby. Distal aortic stent-graft prosthesis <NUM> conforms to the outer surface of a portion of deployed first branch stent-graft prosthesis <NUM> and thus may be partially collapsed by deployed first branch stent-graft prosthesis <NUM>, but lumen <NUM> remains at least partially open for blood to flow through distal aortic stent-graft prosthesis <NUM> due to the relatively smaller size of deployed first branch stent-graft prosthesis <NUM>.

Notably, when first branch stent-graft prosthesis <NUM>, proximal aortic stent-graft prosthesis <NUM>, and distal aortic stent-graft prosthesis <NUM> are deployed as shown in <FIG>, a portion <NUM> of first branch stent-graft prosthesis <NUM> (in its expanded configuration) extends along sufficient overlap <NUM> such that a proximal end of first branch stent-graft prosthesis <NUM> is positioned proximal to sufficient overlap <NUM> and effectively proximally reroutes the ostium of the brachiocephalic artery BCA. Stated another way, at a cross-section of the deployed aortic arch prosthetic assembly <NUM> taken within portion <NUM>, the cross-section includes first branch stent-graft prosthesis <NUM>, proximal aortic stent-graft prosthesis <NUM>, and distal aortic stent-graft prosthesis <NUM>. In this embodiment, first branch stent-graft prosthesis <NUM> extends internal to or inside of proximal aortic stent-graft prosthesis <NUM> (i.e., portion <NUM> of first branch stent-graft prosthesis <NUM> extends within the lumen of proximal aortic stent-graft prosthesis <NUM> and abuts against distal aortic stent-graft prosthesis <NUM>) and thus both first branch stent-graft prosthesis <NUM> and distal aortic stent-graft prosthesis <NUM> are radially disposed within proximal aortic stent-graft prosthesis <NUM> along portion <NUM>. As previously described, however, first branch stent-graft prosthesis <NUM> is configured to exert a higher radial force than distal aortic stent-graft prosthesis <NUM> such that first branch stent-graft prosthesis <NUM> does not collapse due to the contact with distal aortic stent-graft prosthesis <NUM>.

Although second branch stent-graft prosthesis <NUM>/<NUM> is described above as providing perfusion to the left subclavian artery LSA, in another embodiment hereof second branch stent-graft prosthesis <NUM>/<NUM> may be deployed within the left common carotid LCC artery as shown in <FIG>. As shown in <FIG>, a sufficient overlap <NUM> still occurs between proximal and distal aortic stent-graft prostheses <NUM>, <NUM> when second branch stent-graft prosthesis <NUM> is disposed within the left common carotid LCC artery rather than the left subclavian artery LSA. With bypass <NUM> fluidly connecting the left common carotid LCC artery to the left subclavian artery LSA, perfusion of the left common carotid LCC artery via second branch stent-graft prosthesis <NUM> also provides perfusion to the left subclavian artery LSA.

Further, in another embodiment hereof, second branch stent-graft prosthesis <NUM> may an integral extension of distal aortic stent-graft prosthesis <NUM> rather than a separate module or component of the aortic arch prosthetic assembly.

In the method described in <FIG>, proximal aortic stent-graft prosthesis or module <NUM> is deployed or implanted first, followed by deployment of first branch stent-graft prosthesis or module <NUM>, followed by deployment of distal aortic stent-graft prosthesis or module <NUM>, and lastly deployment of second branch stent-graft prosthesis or module <NUM>. This order or sequence prioritizes the establishment of flow and perfusion to the brachiocephalic artery BCA. However, the sequence of deployment of the modules may vary from the order described in <FIG>. For example, in another embodiment hereof, the modules may be deployed from distal to proximal such that distal aortic stent-graft prosthesis or module <NUM> is deployed first, followed by deployment of second branch stent-graft prosthesis or module <NUM>, followed by deployment of proximal aortic stent-graft prosthesis or module <NUM>, and lastly deployment of first branch stent-graft prosthesis or module <NUM>. In another embodiment hereof, the aortic stent-graft prostheses (i.e., proximal aortic stent-graft prosthesis or module <NUM> and distal aortic stent-graft prosthesis or module <NUM>) may both be deployed before the branch stent-graft prostheses (first branch stent-graft prosthesis or module <NUM> and second branch stent-graft prosthesis or module <NUM>).

Claim 1:
A prosthetic assembly (<NUM>) configured for endovascular placement within an aortic arch, the prosthetic assembly (<NUM>) comprising:
a proximal aortic stent-graft prosthesis (<NUM>) including a tubular graft (<NUM>) and at least one stent (<NUM>) coupled to the tubular graft, wherein the proximal aortic stent-graft prosthesis (<NUM>) also includes a coupling (<NUM>) extending from the tubular graft, the coupling (<NUM>) being configured to be positioned proximal to an ostium of a first branch vessel when deployed in situ;
a distal aortic stent-graft prosthesis (<NUM>) including a tubular graft (<NUM>) and at least one stent (<NUM>) coupled to the tubular graft, wherein the distal aortic stent-graft prosthesis (<NUM>) also includes a coupling (<NUM>) extending from the tubular graft;
a first branch stent-graft prosthesis (<NUM>) including a tubular graft (<NUM>) and at least one stent (<NUM>) coupled to the tubular graft, wherein the first branch stent-graft prosthesis (<NUM>) is configured to be disposed through the coupling (<NUM>) of the proximal aortic stent-graft prosthesis (<NUM>) when the proximal aortic stent-graft prosthesis (<NUM>) and the first branch stent-graft prosthesis (<NUM>) are each in an expanded configuration; and
a second branch stent-graft prosthesis (<NUM>) including a tubular graft (<NUM>) and at least one stent (<NUM>) coupled to the tubular graft, wherein the second branch stent-graft prosthesis (<NUM>) is configured to be disposed through the coupling (<NUM>) of the distal aortic stent-graft prosthesis (<NUM>) when the distal aortic stent-graft prosthesis (<NUM>) and the second branch stent-graft prosthesis (<NUM>) are each in an expanded configuration, and
wherein a proximal end (<NUM>) of the distal aortic stent-graft prosthesis (<NUM>) is configured to be disposed within a distal end (<NUM>) of the proximal aortic stent-graft prosthesis (<NUM>) to form an overlap (<NUM>) between the proximal and distal aortic stent-graft prostheses when the proximal and distal aortic stent-graft prostheses are in their respective expanded configurations, the overlap being relatively increased due to the coupling (<NUM>) of the proximal aortic stent-graft prosthesis (<NUM>) being positioned proximal to the ostium of the first branch vessel in situ.