Bifurcation stent-graft assembly

Abstract

A stent assembly that is assembled in situ by separate delivery of two nested stents is configured to maintain a lumen in a bifurcated vessel. The stent assembly includes a first stent with a first opening at a first end, a second opening at a second end, and an intermediate opening on a lateral side of the first stent between the first and second openings. The stent assembly further includes a second stent with a first opening at a first end, a second opening at a second end and an intermediate opening on a lateral side of the second stent between the first and second openings. A portion of the second stent with the intermediate opening is nested within the first stent.

Description

8787-25BIFURCATION STENT-GRAFT ASSEMBLYTECHNICAL FIELD

[0001] The invention relates to stents inserted to repair iliac arteries and the aortoiliac space adjacent to the carina of bifurcation in patients suffering from aortoiliac occlusive disease (AIOD) involving the iliac arteries, aorta, or any combination of blood vessels and their branches.BACKGROUND

[0002] Aorto-iliac occlusive disease (AIOD) refers to narrowing or stenosis of the blood vessels involving the infra-renal aorta and the two iliac arteries (iliacs). In many complex cases of AIOD, the aorto-iliac bifurcation is diseased. AIOD is distinct from the aneurismal disease in that the clinical problem is stenosis, not bulging of the aorta and iliacs. Peripheral arterial disease (PAD) is a circulatory issue that occurs when arteries narrow or block, reducing blood flow to the legs or arms. PAD is treated by dilation and stenting of diseased arteries. In the large arteries such as iliac arteries, stents are expected to exert significant outward force (radial force) against a calcified stenosis.

[0003] Percutaneous transluminal angioplasty (PTA) is used to increase the lumen diameter of an artery that is partially or totally obstructed by atherosclerotic plaque. In PTA, a guiding catheter provides a safe channel from the outside to the targeted stenosis of the artery. A balloon catheter is advanced over guidewire through the guiding catheter, into the artery, and across the stenosis (crossing). The balloon is inflated to expand the narrowing. Dilatation of the occlusion, however, can form flaps, fissures and dissections which threaten abrupt reclosure or perforations of the vessel wall. To treat or prevent such8787-25 events, tubular stents are placed within the angioplasty site to scaffold the vessel lumen. Covered stents add another layer of safety. Stenting of a bifurcation stenoses requires specialized implants and delivery equipment to achieve continuous tissue support throughout the complicated three-dimensional anatomy. A demanding example of such location is a bifurcation of the aorta where the challenge remains poorly addressed. Unfortunately, arthrosclerosis in this area is common.

[0004] It should be understood that the term “stents” includes “bare metal” stents and “stent-grafts”. Stent-grafts are metal stent bodies that carry a jacket coating on the inner and / or outer surface. The coating can be fused or sewn to the stent structure. While in “bare metal” stents only a small percentage of the vessel surface is covered by foreign material, in stent-grafts there is a total coverage which protects from the restenosis, extrusion of plaque and blood leak is in the case of dissection. The type of stents that are used to treat AIOD are generally stent-grafts and called “stents” for simplicity.

[0005] Placement of covered stents in iliac arteries is the standard method of treating AIOD. The stents can be self-expanding but commonly are balloon expandable to facilitate controlled deployment and to maximize radial force. The covered “kissing stents” (KS) technique and the covered endovascular reconstruction of aortic bifurcation (CERAB) technique have been developed to treat AIOD involving the aorto-iliac bifurcation. Both include simultaneous placement of two converging or “kissing” iliac stents across the bifurcation that can protrude up to 2 cm into the aorta. The covered kissing stent technique and CERAB provide a valuable degree of protection from dissection by “covering” the vessel wall from the inside with a polymer film layer fused onto the stent struts. The polymer film is typically expanded polytetrafluoroethylene (ePTFE). However other polymers can be used. Vessel wall dissection is a rare but dangerous event that occurs when a calcified vessel stenosis is “cracked” and dilated with a8787-25 balloon. Junction of the aorta and iliacs is an area of high risk for dissection. Other types of blood vessel wall disruption such as perforation or rapture can be similarly dangerous and even fatal and are treated in a similar way in the context of this disclosure.

[0006] Kissing stents typically require placement of two 8F access sheaths in both femoral arteries. One major shortcoming of kissing stents is the disruption of the natural blood flow through the bifurcation that can lead to uneven perfusion and thrombus formation. Another shortcoming is the need for accurate simultaneous placement of the two kissing stents. Yet another shortcoming is the high technical skill set required to perform this procedure in a way that prevents asymmetry of stents. Further yet, another shortcoming addressed by the inventors is that the two kissing stents make re-intervention procedures using a retrograde approach (up-and-over technique) very challenging.

[0007] Many patients with PAD require interventions in their femoral, popliteal or below the knee (BTK) arteries, the last limitation can be very important. There is a well-recognized need to improve the KS technique in a way that preserves the natural anatomy of aortic bifurcation and facilitate reinterventions. Despite this recognition, there is no product today to treat AIOD that preserves bifurcation close to its natural shape and can be inserted using minimally invasive techniques e.g. through a femoral introducer sheath or sheaths that are less than 12F (French size) or 4 mm in diameter.

[0008] Bifurcated (also called Y-shaped) stent grafts have the advantage of straddling the carina to preserve the natural bifurcation, avoid flow disturbances, and allow for a retrograde approach for re-intervention. However, a shortcoming to this approach is that the self-expanding stent that can be crimped, delivered and expanded using a small sheath may not have sufficient outward force to maintain a patent flow lumen. To deliver and deploy an adequate Y-shape stent requires a greater than 12F introducer. Another shortcoming is the complex8787-25 procedural steps and high technical skill set that is required to place the single piece bifurcated stent graft in the diseased aorto-iliac bifurcation. Thus, the types of cases in which such stent grafts are used are limited.

[0009] Experts in AIOD stenting have been well aware of challenges listed above, but none of the proposed solutions can meet all the requirements. US10716690B2 to Joye “Systems and methods for deploying a luminal prosthesis over a carina” proposed the aorto-iliac stent that splits above the carina and drapes the carina but does not cover aortic walls.US20230210679A1 to Schreck “Devices and methods for treating bifurcating blood vessels” overcomes these limitations but requires stents crimped on the balloon side-by-side like shotgun barrels, which requires at least a 14F-15F introducer (approximately 4.7-5.0 mm), way bigger than the desired access allows.

[0010] There is a need for medical devices and methods for the treatment of AIOD involving the aorto-iliac bifurcation that will overcome the above listed shortcomings of existing methods. The medical devices and methods for the treatment of AIOD involving the aorto-iliac bifurcation described herein fulfill that need.SUMMARY

[0011] The inventors propose a novel approach to stenting of iliac arteries and the aortic segment proximal to bifurcation. The invention involves a novel stenting method and system for treating AIOD while restoring and preserving the natural anatomic aortic bifurcation.

[0012] The procedure and system are characterized by the goals of dividing the flow in the main vessel trunk (e.g., aorta) between two branches (e.g., iliacs) as evenly as practical and without turbulence, recirculation and stagnation of8787-25 blood, following the natural shape of the inner walls of the vessel bifurcation as closely as possible.

[0013] The proposed devices meet all the key expectations of therapy: (a) small caliber femoral access (less than 12F and preferably 8 - 12F or 10F introducer), (b) high radial force in the iliac arteries, (c) protection from dissection, (d) coverage of aorta-iliac bifurcation including carina and junction on the level of carina and (e) simple deployment.

[0014] Put differently, our approach retains the main advantages of KS (Kissing Stents) and more complex CERAB (Covered Endovascular Reconstruction of Aortic Bifurcation) while preserving the natural bifurcation anatomy.

[0015] A principal objective of the present invention is to provide a safe and practical stenting or stent-grafting procedure; corresponding structure and delivery system to treat an aortic or other bifurcation in the vascular system of the patient, which is effective to treat occlusive disease on either side of the carina in the adjacent branch lumens without blocking or inhibiting subsequent guidewire access from an ipsilateral lumen to a contralateral lumen over the carina. The invention is primarily directed towards AIOD but is applicable to other branching vessels in high-risk areas of the body where extra protection is desired when the vessel bifurcation is stretched and stented. It is particularly relevant to large branching arteries in the human leg.

[0016] Tubular radially symmetric stents are often placed to scaffold the vessel lumens in a bifurcation. However, stenting in bifurcation stenoses requires specialized implants and delivery equipment to achieve continuous tissue support throughout the complicated three-dimensional anatomy. Moreover, the implanted device has to provide adequate coverage to seal any leaks arising from possible vessel rupture during device implantation or vessel pre-dilation.8787-25

[0017] The present invention is described as a covered stent system that is designed to treat stenoses in body vessels that change in diameter or shape because of a split of the circulation from the aorta to both legs. The stent has a unique design that allows it to provide continuous covered scaffolding support throughout the complicated three-dimensional anatomy of a bifurcation. The stent may be self-expanding, or balloon expanded and implanted using a unique deployment catheter that allows for proper orientation of the covered stent in the bifurcation.

[0018] An advantage of the proposed system over the prior art is that it (1 ) uses smaller bore vascular access like kissing stents, (2) provides more anatomic restoration of aortic bifurcation anatomy, 3) provides enough overlapping surface area of the covering to eliminate potential leaks due to perforations and 4) maintains a continuous circular or elliptic aortic segment without significantly elevating the carina (as opposed to two protruding “shotgun double barrel” lumens such as what is seen with typical KS and CERAB) which will help with wire cross-over as well as removes any potential gaps that result in endo leaks, stagnation of blood, and clot formation in the areas that would not be covered by KS and CERAB.

[0019] In one aspect of the invention, the invention utilizes a nested design of two stents where both stents have three openings. The stents are partially nested with the overlap reinforcing the most difficult and vulnerable anatomy of the AIOD: the bifurcation of the aorta. Because of the natural turbulence of flow, this region is often diseased and is at risk of dissection. It is desired to cover potential leaks.

[0020] In another aspect of the invention, a stent assembly includes a covered stent having two tubular designs with a side opening in the lattice of metal struts and the polymer covering that uniformly scaffolds and covers vessel8787-25 lumen tissue within a region that significantly changes diameter and / or transverse dimension such as a bifurcation of an aorta.

[0021] In another aspect of the invention, the implanted part of a stent system consists of two asymmetric stents that uniformly scaffolds and covers vessel lumen tissue within a region that significantly changes diameter and shape or transverse dimensions when positioned at a bifurcation of an aorta. Deployment tools may be a part of the system. In addition, the deployment tool may partially reside outside of the body during stent deployment and may be removed from the body after the deployment.

[0022] In another aspect of the invention, a stent assembly is configured to maintain a lumen in a bifurcated vessel. The stent assembly comprises a first stent with a first opening at a first end, a second opening at a second end, and an intermediate opening on a lateral side of the first stent between the first and second openings; and a second stent with a first opening at a first end, a second opening at a second end and an intermediate opening on a lateral side of the second stent between the first and second openings. A portion of the second stent with the intermediate opening is nested within the first stent.

[0023] The intermediate opening may be in the middle of the stent when in a collapsed configuration or longitudinally closer to the first or second opening. The intermediate opening roughly divides the stent into the first distal or aortic portion with the first opening, the intermediate portion with the intermediate opening and the second or proximal portion or section with the second opening. All three portions of the stent may comprise metal scaffolding and polymeric covering intended to restore the natural lumens for blood flow.

[0024] The second stent may extend through the intermediate opening of the first stent, which is configured to receive the second stent. The intermediate opening in the second stent is configured to align with and allow a flow of fluid through a flow path in the first stent from the first opening to the second opening8787-25 in the first stent, wherein the first and second stents are similar in their shape, design and principle of operation, and may be identical and interchangeable. Alternatively, the first and second stents may have different designs and still be interchangeable (or may not be interchangeable).

[0025] Each of the first and second stents comprises an aorta portion configured to be positioned within the aorta and an iliac portion configured to be positioned within an iliac artery, wherein, for each of the first and second stents, a diameter of the aorta portion when fully expanded is larger than a diameter of the iliac portion when fully expanded. Wherein the intermediate opening in the first stent is configured to be aligned with the iliac portion of the second stent so that a plane along the intermediate opening in the first stent is perpendicular to a central longitudinal axis of the iliac portion of the second stent. The intermediate opening in the second stent is configured to be aligned with the iliac portion of the first stent so that a plane along the intermediate opening in the second stent is perpendicular to a central longitudinal axis of the iliac portion of the first stent. Each of the first and second stent comprises scaffolding enclosed at least partially by a covering. As a result, a continuous blood flow path is created that evenly divides blood flow in the distal aorta between two arteries that perfuse legs. It also allows a continuous access path for post-operation stenting of distal blood vessels in either leg and access by re-operation catheter instruments.

[0026] In another aspect of the invention, a stent assembly is configured to expand and maintain a lumen in a bifurcated vessel. The stent assembly comprises a first covered stent with a first opening in a side wall of the first covered stent; and a second stent with a second opening in a side wall of the second stent, wherein a portion of the second stent including the second opening is positioned inside the first covered stent.

[0027] The second stent may be configured to extend through the first opening, wherein the first and second openings are positioned to face opposite8787-25 lateral directions, wherein the first and second stents are positioned in orientations that laterally mirror each other. The first and second stents are interchangeable and may be substantially identical. Wherein each of the first and second stents comprises a wider portion with a first diameter and a narrower portion with a second portion. The wider portion of the second stent is nested within the wider portion of the first covered stent. A length of the wider portion of the first covered stent is equal to or longer than a length of the wider portion of the second stent so that the wider portion of the first covered stent fully overlaps the wider portion of the second stent and may extend beyond the wider portion of the second stent. The first opening is configured to be aligned with the narrower portion of the second stent. The second opening is configured to be aligned with the narrower portion of the first covered stent.

[0028] In yet another aspect of the inventions, a method of opening a narrowed region in a bifurcated blood vessel (e.g., aortic bifurcation)comprises the steps of: deploying a first covered stent through a first iliac branch of the aortic bifurcation and partially into a main trunk (aorta) of the aortic bifurcation; expanding and aligning the first covered stent so that a first opening in a sidewall of the first stent is aligned with a second iliac branch of the aortic bifurcation and positioned within the main trunk of the aorta bifurcation; deploying a second covered stent through the second iliac branch of the aortic bifurcation and partially into the main trunk of the aortic bifurcation; expanding and aligning the second covered stent so that a second opening in a sidewall of the second stent is aligned with the first iliac branch of the bifurcated blood vessel.

[0029] The said sidewalls of the first and the second stents may have protruding metal strut elements that support the polymeric covering, which creates an overlap in the area where the two stents have aligned intermediate openings. This overlap facilitates coverage and protection of the carina and immediately adjacent inner walls of the bifurcating aorta.8787-25

[0030] A portion of the second covered stent may be deployed through the first opening, wherein the second opening is aligned to allow a flow of blood from the main trunk of the bifurcated blood vessel to the first branch of the bifurcated blood vessel, through the second opening, wherein the first and second openings are oriented to face diverging directions so that the central longitudinal axes of the first and second openings are angled relative to each other (e.g., 30 to 65 degrees such as 45 degrees). The first and second covered stents are selfexpanding and / or are expanded by deploying and inflating corresponding balloons.

[0031] Each of the first and second covered stents comprises: a trunk portion deployed in the main trunk of the bifurcated blood vessel; and a branch portion deployed in one of the branches of the bifurcated blood vessel. The diameters of the trunk portions are greater than the diameters of the branch portions, wherein the trunk portion of the second covered stent is nested inside the trunk portion of the first covered stent. The trunk portion of the first covered stent extends beyond the trunk portion of the second covered stent. An outer surface of the trunk portion of the second covered stent abuts an inner surface of the trunk portion of the first covered stent.

[0032] In yet another aspect of the invention, a system includes two stents that have a proximal and a distal segment where the distal segment when expanded resides in the aorta and the proximal segment resides in the first or second iliac artery. The stents are delivered in a collapsed linear configuration where they have the same diameter in the collapsed state. When the stents are deployed, the aortic portion expands to a diameter larger than the iliac section. The aortic sections are at least partially nested inside each other.

[0033] The stents are deployed and expanded sequentially. When the first stent is deployed through the ipsilateral iliac artery and expanded it forms an opening between the aortic and iliac sections that is aligned with the ostium of8787-25 the contralateral iliac artery. The second stent can be inserted, deployed and expanded through that opening. The second deployed stent also forms an opening that is aligned with the ostium of the ipsilateral iliac artery. The step of aligning can be assisted by the indications on the handle of the delivery system that are outside of the body (o’clock dial) and by radiopaque markers incorporated in the stent design and / or in the shaft of the delivery system.

[0034] In accordance with another aspect of the present invention, a method is provided for treating a bifurcation between a main lumen (aorta) and two branch lumens (iliac arteries). The method includes the steps of providing radially expandable stents, stent grafts, also often called vascular prosthesis, having a proximal end, a distal end, a support structure, a circumferential structure that forms a side opening when expanded in the lumen. The first prosthesis is navigated to the treatment site using endovascular access techniques. The first prosthesis is deployed at the site such that the supporting structure is expanded in the larger main lumen by a first diameter section, and to the second smaller diameter when expanded in the branch lumen by a second diameter in the iliac artery while forming an opening through which the second similar prosthesis is inserted and expanded in the similar way to form a diverging mirror structure in the contralateral iliac artery and a nested coaxial structure in the aorta. Deployment of the stent (i.e., expansion) may begin in the aorta and end in the iliac artery. In addition, deployment of stent can be from the middle of the stent by a split sheath. Deployment may include steps of partial deployment, recovery, redeployment, axial rotation and linear repositioning to achieve alignment.

[0035] In another aspect of the invention, the stents are self-expanding stents and delivered by the delivery system in liner arrangement constrained by the retractable sheath. The retractable sheath may be gradually pulled back to8787-25 allow the stent to expand and come to the apposition with the walls of the blood vessel.

[0036] In another aspect of the invention, the stent is deployed gradually. The deployment may start in the aorta and end in the iliac artery. The stent may be laterally aligned with the contralateral iliac by rotating the delivery system using the handle of the delivery system. It is contemplated that the deployment can be first made longitudinally partial to ensure the longitudinal and radial alignment with the anatomy and can be interrupted with the stent collapsed back into the sheath by advancing the sheath followed by the step of repositioning and redeployment of the stent. Alternatively, deployment can be initially limited to a partially expanded state in which the stent can be manipulated into alignment. After alignment, the stent can be fully deployed in a fully deployed state.

[0037] In another aspect of the invention, the stent is laser cut from the NiTi tube of consistent diameter and shape set to expand to two different diameters when released from the constrained state. Alternatively, the stent may be a balloon expandable stent.

[0038] In another aspect of the invention, a method comprises the steps of providing a catheter having a balloon with at least a first section having a relatively small, inflated diameter and a second section having a relatively larger inflated diameter. The balloon is positioned across the opening of an iliac artery from a main trunk (across the carina). The balloon is thereafter inflated such that the first section is inflated at least partially within the iliac vessel and the second section is inflated at least partially within the aorta. Alternatively, two balloons can be assembled linearly on the same shaft and the stent can be crimped upon two linearly arranged non-compliant balloons of smaller and larger diameter.

[0039] In another aspect of the invention, the two stents are deployed into the aortic bifurcation and after deployment in combination form a polymer covered scaffolding that approximates the natural bifurcation and covered portion8787-25 of iliac arteries, carina and aortic walls adjacent to the bifurcation and extending into the aorta. The iliac portions may extend into the iliac arteries at least 10 mm from bifurcation and the aortic portion may extend into the aorta at least 10 mm from bifurcation. The level of bifurcation may be the level of the carina equidistant from the axis of the first and second iliac ostium.

[0040] In another aspect of the invention, a system is configured to treat an aorto-iliac bifurcation stenosis and includes a first stent with a first opening at a proximal end, a second opening at a distal end, and an intermediate opening on a side of the first stent between the first and second openings; and a second stent with a first opening at a proximal end, a second opening at a distal end, and an intermediate opening on a side of the second stent between the first and second openings, wherein a portion of the second stent with the intermediate opening is nested within the first stent.

[0041] The first and second stents are configured to be delivered to an aorto-iliac bifurcation in a collapsed linear and coaxial configuration. For each of the first and second stents, the intermediate opening can be a slit or punched hole that is less than 50% of the circumference of the stent when the stent is in the collapsed state. The intermediate opening can also have a protruding fenestration designed to facilitate overlapping covering of carina and adjacent iliac artery ostium. Ostium in this context is a funnel-like structure of the internal arterial walls.

[0042] The first stent is oriented and deployed so that the slit or punched hole becomes the intermediate opening and is aligned with the contralateral iliac ostium. Each of the first and second stents comprises an aortic section and an iliac section. For each of the first and second stents, the aortic section is shape set to a larger diameter than the iliac section. The second stent delivery system is inserted through that opening and expanded inside the first stent so that aortic sections of two stents are nested and overlap and iliac sections of two stents8787-25 diverge at an angle to the aortic axis and form an inverted Y-shape scaffolding approximating the aortic bifurcation. The first and second stents are selfexpanding covered stents.

[0043] In another aspect of the invention, an asymmetric stent is configured to maintain a lumen in a bifurcated vessel. The asymmetric stent has a first opening and a second opening opposite the first opening. A first tubular portion has a distal end and a proximal end. The first tubular portion also has a first diameter when fully expanded. The first opening is at the distal end of the first tubular portion. A second tubular portion of the asymmetric stent has a distal end and a proximal end. The distal end of the second tubular portion is connected to the proximal end of the first tubular portion. In addition, the second tubular portion has a diameter when fully expanded that is smaller than the first diameter. The second opening opposite the first opening and is located at the proximal end of the second portion. A third (intermediate) opening is located between the first and second openings, wherein the second tubular portion is configured to pivot relative to the first tubular portion at the distal end of the second tubular portion, and wherein the third opening is located adjacent to the pivotable connection between the first and second portions.

[0044] Part of the first portion extends radially beyond the second portion when fully extended, the part of the first portion that extends radially beyond the second portion when fully extended forms the third opening. A covering covers the first and second portions of the stent. The covering has an opening at the third (intermediate) opening. A plurality of radiopaque markers are configured to indicate a position of the stent relative to the vessels in which the stent is inserted. The markers are radiopaque markers and include markers that are positioned adjacent to the third opening, the plurality of markers includes markers that are positioned at the proximal end of the second portion and at the distal end of the first portion.8787-25

[0045] In another aspect of the technology, a stent has an expandable scaffolding and is configured to transform from an unexpanded tubular state to an expanded bifurcated state. The stent comprises a first tubular section located at a first end of the stent when the stent is in the unexpanded tubular state, the scaffolding being arranged in a first pattern in the tubular branch. A second tubular section is located at a second opposite end of the stent when the stent is in the unexpanded tubular state, the scaffolding being arranged in a second pattern in the tubular trunk section that is the same as the first pattern. An intermediate section that intervenes between the first and second tubular sections, the scaffolding being arranged in a third pattern in the intermediate section that is different from the first and second patterns. The third pattern includes a first gap and a second gap on opposite sides of the intermediate longitudinal axis of the stent. The intermediate section is configured so that bending the stent at the intermediate section increases the size of the first gap and decreases the size of the second gap.

[0046] A rim around the first gap is configured to protrude from a side of the tubular shape when the first gap increases in size. A rim may have protruding elements, marker elopements and flexibility elements to improve placement.

[0047] The expandable scaffolding may be configured so that when the stent is expanded and bent at the intermediate section, the first tubular section transforms into a first trunk portion with a first diameter, the second tubular section transforms into a second branch portion with a second diameter that is less than the first diameter, and the rim around the first gap transforms into a second branch portion that is shorter than the first branch portion and has the same diameter as the first branch portion.

[0048] Alternatively, the expandable scaffolding may be configured so that when the stent is expanded and bent at the intermediate section, the first tubular section transforms into a first branch portion with a first diameter, the second8787-25 tubular section transforms into a second branch portion with a second diameter that is the same as the first diameter, and the rim around the first gap transforms into a trunk portion with a third diameter that is larger than the first and second branch portions.

[0049] In another alternative, the expandable scaffolding is configured so that when the stent is expanded and bent at the intermediate section, the first tubular section transforms into a first branch portion with a first diameter, the second tubular section transforms into a second branch portion with a second diameter, and the intermittent portion transforms into an intermittent opening characterized by flexibility elements and protrusions adapted to receive the second stent for nesting and support an overlap seal between the nested stents where the nested stents join.

[0050] The first and second patterns comprise a plurality of linearly or laterally repeating shapes when the scaffolding is flattened. The third pattern comprises shapes that are repeatably arranged around a central point when flattened. The third pattern further comprises a plurality of linearly repeating shapes when flattened. Markers (radiopaque markers) in the scaffolding that are positioned to indicate the location of at least one of a first end of the stent at the first tubular section, a second end of the stent in the second tubular section, and the first and second gaps. At least some of the markers are positioned adjacent to the first and second gaps, particularly where the stent overlaps the carina.

[0051] In some embodiments the stent is configured to transform from a radially symmetric tubular structure to an asymmetric bifurcated structure by bending the linear tubular structure at the intermediate section, the asymmetric bifurcated structure having a main trunk and two branches, the branches having different lengths and the main trunk having a greater diameter than the two branches.8787-25

[0052] In another aspect of the technology, a stent has an expandable scaffolding and is configured to transform from an unexpanded tubular state to an expanded bifurcated state. The stent comprises a first tubular section located at a first end of the stent when the stent is in the unexpanded tubular state. The scaffolding in the first tubular section comprises a plurality of linearly or laterally repeating shapes configured to form a plurality of rings. A second tubular section is located at a second opposite end of the stent when the stent is in the unexpanded tubular state. The scaffolding in the second tubular section comprises a plurality of linearly or laterally repeating shapes configured to form a plurality of rings. An intermediate section that intervenes between the first and second tubular sections. The scaffolding in the intermediate section comprises a pattern radially extending from a gap that is configured increase in size upon the stent being bent at the intermediate section. A rim around the gap is configured to protrude outward from a side wall of the stent when the stent is bent at the intermediate section and the central increases in size.

[0053] The expandable scaffolding is configured so that when the stent is expanded and bent at the intermediate section, the first tubular section transforms into a first trunk portion with a first diameter, the second tubular section transforms into a first branch portion with a second diameter that is less than the first diameter, and a rim around the gap transforms into a second branch portion that is shorter than the first branch portion and has the same diameter as the first branch portion. Alternatively, the expandable scaffolding is configured so that when the stent is expanded and bent at the intermediate section, the first tubular section transforms into a first branch portion with a first diameter, the second tubular section transforms into a second branch portion with a second diameter that is the same as the first diameter, and a rim around the gap transforms into a trunk portion with a third diameter that is larger than the first and second branch portions.8787-25

[0054] The scaffolding in the intermediate section further comprises a plurality of linear patterns that are separated from the first and second tubular sections. Markers in the scaffolding that are positioned to indicate the location of at least one of a first end of the stent at the first tubular section, a second end of the stent in the second tubular section, and the central gap. At least some of the markers are positioned adjacent to the central gap. The stent is configured to transform from a linear tubular structure to an asymmetric bifurcated structure by bending and radially expanding the tubular structure at the intermediate section, the asymmetric bifurcated structure having a main trunk and two branches, the branches having different lengths and the main trunk having a greater diameter than the two branches.

[0055] In another aspect of the invention, a stent assembly comprises a pair of stents according to any one of stents discussed above.

[0056] A portion of a first one of the pair of stents is configured to nest a second one of the pair of stents and the second one of the pair of stents is configured to be nested within the first one after the steps of deployment and expansion.

[0057] In other embodiments the intermittent portion of the second stent is partially nested within the intermittent portion of the first stent. In some embodiments the intermittent section is isometric and comprises an opening or a gap and a rim. In some embodiments stents comprise a second gap opposite the first gap. In some embodiments the rim is comprised of protruding elements (petals), markers and flex elements to facilitate covering and restoring the carina and adjacent parts of aorto-iliac junction.SUMMARY OF FIGURES

[0058] FIG. 1 A illustrates sectional views of different parts of an aorta-iliac bifurcation region.8787-25

[0059] Fig. 1 B illustrates a side view of the aorta-iliac bifurcation region.

[0060] Fig. 1 C illustrates a side view of “kissing stents” in an aortabifurcation region.

[0061] Figs. 1 D and 1 E illustrate cross-sectional views of the “kissing stents” in the aorta-bifurcation region.

[0062] Fig. 1 F illustrates a side view of “CERAB” configuration in an aortabifurcation region.

[0063] Figs. 1 G and 1 H illustrate cross-sectional views of the “CERAB” configuration in the aorta-bifurcation region.

[0064] Fig. 2A illustrates an exemplary stent assembly comprised of a pair of covered asymmetric stents.

[0065] Fig. 2B illustrates an exemplary stent assembly comprised of a pair of partially covered stents.

[0066] Fig. 2C illustrates blood flow through the stent assemblies of Figs.2A and 2B.

[0067] Fig. 3A illustrates the scaffolding of an exemplary stent in a flattened state.

[0068] Fig. 3B illustrates an uncovered expanded stent using the scaffolding pattern of Fig. 3A.

[0069] Figs. 3C and FIG. 3D illustrate the expanded stent of Fig. 3B with a covering.

[0070] Figs. 3E-3G illustrate alternate scaffolding patterns for the asymmetric stents.

[0071] Figs. 4A-4C illustrate the installation of asymmetric stents.

[0072] Figs. 5A-5E illustrate another installation procedure for installing an asymmetric stent.

[0073] Figs. 6A-6F illustrate another installation procedure for installing a first asymmetric stent.8787-25

[0074] Figs. 7A-7F illustrate the installation of a second asymmetric stent.

[0075] Figs. 8A-8B illustrate an exemplary delivery system for the asymmetric stents of Figs. 6A-7F.DETAILED DESCRIPTION

[0076] Figs. 1 A and 1 B illustrate the geometry of the aorta-iliac bifurcation region 10. The aorta-iliac bifurcation region 10 is where the transverse dimension of the aorta 12 becomes larger and asymmetric just before a division occurs at the level of the carina 14. The cross-sections illustrated in Fig. 1 A show that, at the bifurcation, the aorta 12 is not radially symmetrical. The aorta 12 expands in a direction across the ostia of iliac lumens without enlarging perpendicularly thereby forming a generally oval transverse section 16. The ipsilateral iliac artery 18 and contralateral iliac artery 20 extend from the generally oval transverse section 16 and each has a generally circular cross-sectional shape.

[0077] As previously discussed, the “kissing stent” (KS) technique and the covered endovascular reconstruction of aortic bifurcation (CERAB) technique have been developed to treat AIOD involving the aorto-iliac bifurcation. However, due to the varying cross-sectional shape in the aorta-iliac bifurcation region 10, the KS and CERAB techniques are unable to provide uniform scaffolding over the entire length between the circular portion of the aorta 12 and the oval transverse section 16.

[0078] Figs. 1 C-E show first and second symmetrical stents 22, 24 deployed within the aorta 12, the ipsilateral iliac artery 18, and the contralateral iliac artery 20. Because the combined shape of the first and second symmetrical stents 22, 24 does not have a circular cross-sectional shape, the geometry of the resulting bifurcation flow path deviates from its original natural geometry.Accordingly, gaps 26 are left between the first and second symmetrical stents 22, 24 and the wall of the aorta 12.8787-25

[0079] Figs. 1 F-H show first and second symmetrical iliac stents 28, 29 that extend into the aorta 12 and are capped by an aorta cap stent 30. However, similar to the configuration illustrated in Figs. 1 F-H, the configuration of Figs. 1 F- H results in a bifurcation flow path that deviates from its original natural geometry, which leaves a gap 32 between the wall of the aorta 12 and the stents as well as a gap 33 inside the aorta cap stent 30 between the first and second symmetrical iliac stents 28, 29. These gaps allow the blood flow in the aorta-iliac bifurcation region 10 to leak outside the stents, which in turn leads to a further buildup of atherosclerotic plaque.

[0080] In contrast, the stent assembly 34 illustrated in Fig. 2A conforms to the shape of the aorta-iliac bifurcation region 10. Thus, despite the varying cross- sectional shapes in the aorta-iliac bifurcation region 10, the stent assembly 34 provides substantially uniform scaffolding over its entire length. In addition, the overlapping covered structure of the stent assembly 34 forms a continuous cover over the diseased portions of the bifurcation zone (buildup of atherosclerotic plaque). Unlike previous “branching” stent configurations such as “chimney” or “snorkel” stent configurations, the stent assembly 34 forms a smooth flow profile that follows the natural flow path of a bifurcated vessel, which mitigates and minimizes the risk of perforations and blood leakage out of the stent assembly 34.

[0081] Fig. 2A illustrates an exemplary stent assembly 34 that is assembled within the aorta-iliac bifurcation region 10 (or any other bifurcated vessel) and configured to treat AIOD. The stent assembly 34 may include two or more covered stents that fit together to expand, cover and reinforce a stenosed aortoiliac bifurcation region. As a result, the bifurcation flow path is restored close its natural geometry. The configuration illustrated in Fig. 2 includes a first asymmetric stent 35 and a second asymmetrical stent 36 that is partially nested within the first asymmetric stent 35. The first and second stents 35, 36, are8787-25 shown in the fully expanded position desired after the treatment of stenosis. The first and second stents 35, 36 together uniformly scaffold and cover vessel lumen inner walls within a region that significantly changes diameter and shape or transverse dimensions (e.g., the bifurcation region). It is contemplated that the asymmetrical shape of each stent occurs when the stent is fully expanded. When collapsed, (e.g., crimped into the delivery system) the stents may be at least one of symmetrical, linear, and coaxial.

[0082] When fully deployed and expanded, the first and second asymmetric stents 35, 36 exert a combined force against vessel walls where they are nested. In addition, the overlapping of the stent coverings provides an additional seal against leaks outside of the stent assembly 34. The nested portion of the stent assembly 34 may extend from the aorta 12 to the oval transverse section 16, as well as the carina 14 and the proximal parts of inner walls of the iliac arteries 18, 20 that form the walls of the bifurcation zone.

[0083] The first asymmetric stent (ipsilateral stent) 35 may be positioned within the ipsilateral iliac artery 18 and may extend into the aorta 12. In addition, the second asymmetric stent (contralateral stent) 36 may be positioned within the contralateral iliac artery 20 and may also extend into the aorta 12. Each of the first and second asymmetric stents 35, 36 may be covered with a membrane (e.g., EPTFE or TPU) and may have self-expanding scaffolding or may be expanded by way of a balloon.

[0084] The stent assembly 34 may be comprised of a plurality of stents with two of the stents being asymmetric. The first and second asymmetric stents 35, 36 may be similar or almost identical in design and / or interchangeable and may be oriented to laterally mirror each other. The second stent 36 may be at least partially nested within the first stent 35 or vice versa.

[0085] The first asymmetric stent 35 may include an aorta portion 38 configured to be positioned within the aorta 12, an iliac portion 39 configured to8787-25 be positioned within the ipsilateral iliac artery 18, and an intermediate region 40 that connects the aorta portion 38 to the iliac portion 39. The cross-sectional area of the first asymmetric stent 35 may be greater in the aorta portion 38 than in the iliac portion 39. In addition, the cross-sectional area of the intermediate region 40 may increase from the aorta portion 38 toward the iliac portion 39.

[0086] The first asymmetric stent 35 may have a first (inlet) opening 41 at the end of the aorta portion 38 through which blood in the aorta 12 enters the first asymmetric stent 35 as well as the stent assembly 34.

[0087] The first asymmetric stent 35 may also have a second (outlet) opening 42 at the end of the iliac portion 39 through which a fraction of the blood flowing through the first asymmetric stent 35 exits the first asymmetric stent 35. In addition, the first asymmetric stent 35 may include a third (intermediate or outlet or contralateral) opening 43 located at the intermediate region 40 between the first and second openings 41 , 42. A fraction of the blood flowing through the first asymmetric stent 35 exits the first asymmetric stent 35 through the third opening 43.

[0088] The second asymmetric stent 36 may include an aorta portion 44 configured to be positioned within the aorta 12, an iliac portion 46 configured to be positioned within the ipsilateral iliac artery 18, and an intermediate region 48 that connects the aorta portion 44 to the iliac portion 46. The cross-sectional area of the second asymmetric stent 36 may be greater in the aorta portion 44 than in the iliac portion 46. In addition, the cross-sectional area of the intermediate region 48 may increase from the aorta portion 44 toward the iliac portion 46.

[0089] The second asymmetric stent 36 may have a first (inlet) opening 50 at the end of the aorta portion 44 through which blood in the aorta 12 enters the second asymmetric stent 36 as well as the stent assembly 34.

[0090] The second asymmetric stent 36 may also have a second (outlet) opening 52 at the end of the iliac portion 46 through which a fraction of the blood8787-25 flowing through the second asymmetrical stent 36 exits the second asymmetric stent 36. In addition, the second asymmetric stent 36 may include a third (intermediate or outlet) opening 54 located at the intermediate region 48 between the first and second openings 50, 52. A fraction of the blood flowing through the second asymmetric stent 36 exits the second asymmetric stent 36 through the third opening 52.

[0091] When fully deployed in their final position, the intermediate openings 43, 54 of the first and second asymmetric stents 35, 36 face away from each other in generally opposite lateral directions. In addition, the iliac portions 39, 46, of the first and second asymmetric openings 35, 36 may extend from the respective aorta portions 38, 44 in a direction that is in the inferior direction away from each other.

[0092] The aorta portion 44 along with the intermediate region 48 of the second asymmetric stent 36 may be positioned entirely within the aorta portion 38 and intermediate region 40 of the first asymmetric stent 35 so that the second asymmetric stent 36 is partially nested within the first asymmetric stent 35. In this configuration, the iliac portion 46 of the second asymmetric stent 36 may be the only part of the second asymmetric stent 36 not contained within the first asymmetric stent 35. In addition, no part of the first asymmetric stent 35 may be positioned inside of the second asymmetric stent 36. It should be understood that when the second asymmetric stent 36 is inserted into the aorta-iliac bifurcation region 10, the nesting configuration described above may be reversed so that the first asymmetric stent 35 is partially nested within the second asymmetric stent 36.

[0093] It is contemplated that the intermediate regions 40, 48 of the first and second asymmetric stents 35, 36 may include protruding elements that are configured to expanded outward beyond the tubular structure of the corresponding asymmetrical stent to improve the nesting or overlapping ofasymmetrical stents in the carina 14 and adjacent areas of bifurcation. The protruding elements may be located around the rim of the intermediate opening 43, 54 to form a lip, flange, or flare around a portion of or the entire perimeter of the intermediate opening 43, 54.

[0094] As discussed above, the first and second asymmetric stents 35, 36 may have identical or semi-identical structures. However, it is contemplated that the aorta portion 44 of the second asymmetric stent 36 may be shorter than the aorta portion 38 of the first asymmetric stent 35 (or vice versa if the first asymmetric stent 35 is nested in the second asymmetric stent 36) so that when the first and second asymmetric stents 35, 36 are fully expanded and positioned within the aorta 12, the aorta portion 38 of the first asymmetric stent 35 extends beyond the aorta portion 44 of the second asymmetric stent 36. Alternatively, the aorta portions 38, 44 of both stents may have the same length so that neither stent extends past the other in the superior direction when fully expanded and positioned within the aorta 12.

[0095] Looking at the first asymmetric stent 35, upon being in the fully deployed position, the intermediate opening 43 may face the ipsilateral iliac ostium and may be sized to accommodate the fully extended diameter or cross- sectional area of the iliac portion 46 of the second asymmetric stent 36. It is contemplated that the intermediate opening 43 may be smaller when the first asymmetric stent 35 is fully deployed but further enlarged by the expansion of the second asymmetric stent 36. In addition, the shape of the intermediate opening 43 may be different than the cross-sectional shape of the iliac portion 46 of the second asymmetric stent 36. For example, the cross-sectional shape of the iliac portion 46 may be circular, while the shape of the intermediate opening 43 (fully deployed prior to receiving the iliac portion 46) may have one or more vertices and / or may be ovoid shaped. Alternatively, the fully deployed shape of the intermediate opening 43 (prior to receiving the iliac portion 46) may be the sameas the cross-sectional shape of the iliac portion 46 of the second asymmetric stent 36.

[0096] Looking at the second asymmetric stent 36, upon being in the fully deployed position, the intermediate opening 48 may face the contralateral iliac ostium and may be sized to be substantially the same as the fully extended diameter or cross-sectional area of the iliac portion 39 of the first asymmetric stent 35. It is contemplated that the intermediate opening 48 may be large enough when fully expanded to press against the inner surface of the fully deployed first asymmetric stent 35. In addition, the shape of the intermediate opening 48 may be different than the cross-sectional shape of the iliac portion 39 of the first asymmetric stent 35. For example, the cross-sectional shape of the iliac portion 39 may be circular, while the shape of the intermediate opening 48 (fully deployed) may have one or more vertices. Alternatively, the fully deployed shape of the intermediate opening 48 may be the same as the cross-sectional shape of the iliac portion 39 of the first asymmetric stent 35.

[0097] Since stents are deployed into the stenosed constricted vasculature it is contemplated that the resulting stented lumens may be expanded by balloons after deployment. Alternatively, the stents may be self-expanding.

[0098] Fig. 2B shows an alternative configuration of the stent assembly 34 in which the covering on the second asymmetric stent 36 does not completely cover the scaffolding in the aorta portion 44. For example, the scaffolding in the ipsilateral side of the aorta portion 44 of the second asymmetric stent 36 may remain uncovered or “bare metal” scaffolding.

[0099] Fig. 2C illustrates how the stent assembly 34 maintains blood flow through the aorta-iliac bifurcation region 10. As can be seen, blood flow is represented by the arrows. Since the walls of the first and second asymmetric stents 35, 36 conform to the shape of the varying cross-sectional shape of the bifurcation, the walls of the first and second asymmetric stents 35, 36 do not8787-25 interfere with the flood of blood through the aorta-iliac bifurcation region 10 and the natural flow of blood through the aorta-iliac bifurcation region 10 is maintained.

[0100] Figs. 3A and 3B illustrate a scaffolding pattern (or a skeleton made of struts, rings and bridges) for the first asymmetric stent 35. Fig. 3A shows the scaffolding pattern as it would look if flattened out, and Fig. 3B shows the scaffolding rolled up in the expanded configuration. It should be understood that the first and second stents 35, 36 may have identical structures. The only difference between the two stents may be the orientations of the branches of the bifurcated structure after deployment, which is due to the particular artery through which the stent is inserted. Thus, the structure shown in Figs. 3A and 3B as well as the description below also applies to the second asymmetric stent 36.

[0101] The scaffolding or skeleton of the first and second asymmetric stents 35, 36 may be formed from a continuous body made of “shape memory” material such as, for example, nitinol. In the aorta portion 38 of the first asymmetric stent 35 (i.e., the “main trunk” of the bifurcated structure formed when the first asymmetric stent 35 is expanded). The aorta portion 38 may be formed from a plurality of aorta portion rings 56 attached to each other by intra-sectional bridges 58. Figs. 3A and 3B show the aorta portion 38 being formed from five aorta portion rings 56. However, the aorta portion 38 may be formed from more or less aorta portion rings 56 depending on the desired depth of penetration into the aorta 12.

[0102] Each aorta portion ring 56 may have a “Z” or zig-zag pattern and may be formed from a plurality of aorta portion struts 60 that may be arranged in a “Z” or zig-zag pattern. Alternatively, the aorta portion struts 60 may be arranged in a “sinusoidal” repeating triangle pattern, diamond pattern, or other ring pattern known in stent designs. The aorta portion struts 60 may be attached to an adjacent aorta portion ring 56 by one or more intra-sectional bridges 58.8787-25

[0103] Figs. 3A and 3B show three intra-sectional bridges 58 connecting each pair of adjacent aorta portion rings 56. However adjacent aorta portion rings 56 may be attached to each other by more or less than three intra-sectional bridges 58. In addition, the intra-sectional bridges 58 connecting adjacent aorta portion rings 56 may be equally spaced from each other to provide structural stability between the aorta portion rings 56 (e.g., to minimize or prevent movement of the aorta portion rings 56 toward and away from each other, while still maintaining a level of flexibility). Also. The intra-sectional bridges 58 may have similar shapes as the aorta portion struts 60. For example, the intra- sectional bridges 58 may be in the form of linear beams or “C” or “S” shaped beams for additional flexibility. The particular configuration of the aorta portion rings 56 and the intra-sectional bridges 58 allows the aorta portion 38 to maintain a tubular or cylindrical shape during deployment.

[0104] The iliac portion 39 of the of the first asymmetric stent 35 may form one of the branches of the bifurcated structure formed when the first asymmetric stent 35 is expanded. In addition, the iliac portion 39 may have a similar structure as the aorta portion 38 except that the diameter of the iliac portion 39 (when fully deployed) may be smaller than the diameter of the aorta portion 38 (when fully deployed).

[0105] The iliac portion 39 may be formed from a plurality of iliac portion rings 62 attached to each other by intra-sectional bridges 63. Figs. 3A and 3B show the iliac portion 39 being formed from five iliac portion rings 62. However, the iliac portion 39 may be formed from more or less iliac portion rings 62 depending on the desired depth of penetration into the contralateral iliac artery 20 (or ipsilateral iliac artery 18 for the second asymmetric stent 36). In addition, it is contemplated that the length of the aorta portion 38 may be longer than, shorter than or equal to the length of the iliac portion 39.8787-25

[0106] Each iliac portion ring 62 may have a “Z” or zig-zag pattern and may be formed from a plurality of iliac portion struts 64 that may be arranged in a “Z” or zig-zag pattern. Alternatively, the iliac portion struts 64 may be arranged in a “sinusoidal” repeating triangle pattern, diamond pattern, or other ring pattern known in stent designs. The iliac portion struts 64 may be attached to an adjacent iliac portion ring 62 by one or more intra-sectional bridges 63.

[0107] Figs. 3A and 3B show three intra-sectional bridges 63 connecting each pair of adjacent iliac portion rings 62. However, adjacent iliac portion rings 62 may be connected to each other by more or less than three intra-sectional bridges 63. In addition, the intra-sectional bridges 63 connecting adjacent iliac portion rings 62 may be equally spaced from each other to provide structural stability between the iliac portion rings 62 (e.g., to minimize or prevent movement of the iliac portion rings 62 toward and away from each other, while still maintaining a level of flexibility). Also, the intra-sectional bridges 63 may have similar shapes as the iliac portion struts 64. For example, the intra-sectional bridges 63 may be in the form of linear beams or “C” or “S” shaped beams for additional flexibility.

[0108] The scaffolding or skeleton in the intermediate region 40 of the first asymmetric stent 35 may be the portion that transitions from the aorta portion 38 and the iliac portion 39 and may have a completely different pattern than the aorta and iliac portions 38, 39. The intermediate region 40 may include an opening portion that forms the intermediate opening 43, a lip portion that forms a lip 66 at an edge of the opening 43, and a radial support portion that provides support along the length of the intermediate region 40.

[0109] The opening portion of the intermediate region 40 includes a pair of axially extending struts 65 that extend from one of the aorta portion rings 56 to the lip 66 to form the lateral sides of the intermediate opening 43. Accordingly, the intermediate opening 43 may be bound by the axially extending struts 65,8787-25 one of the aorta portion rings 56, and the lip 66 and may be positioned so that bending the first asymmetric stent 35 at the intermediate region 40 (and / or expanding the first asymmetric stent 35 as a whole) increases the size of the intermediate opening 43. The axially extending struts 65 may include “C” or “S” shaped portions that increase flexibility.

[0110] The lip portion of the intermediate region 40 may have a hybrid pattern and may include the lip 66 and a radially repeating pattern 67 partially or completely around the lip 66. The lip 66 may comprise a linear pattern similar to the aorta portion rings 56 and the iliac portion rings 62. For example, the lip 66 may have a “Z” or zig-zag pattern or may be arranged in a “sinusoidal” repeating triangle pattern, diamond pattern, or other linear pattern known in stent designs. The radially repeating pattern 67 around the lip 66 may include repeating petallike, ovoid, or elliptical shapes similar to the “ray flowers” of a daisy that repeat at least partially around the lip 66. The lip 66 may be connected to the radially repeating pattern 67 at opposing ends of the lip 66. In addition, the radially repeating pattern 67 may be connected to the iliac portion 39 by way of a pair of intersectional bridges 76. The intersectional bridges 76 may be S-shaped or may have an embedded “C” shape.

[0111] As the size of the intermediate opening 43 is increased by bending and / or expanding the first asymmetric stent 35, the radial pattern may pivot to move the lip 66 radially outward so that the lip 66 forms a lip, flange, or flared portion that bounds the iliac side of the intermediate opening 43 and protrudes outward from the side of the first asymmetric stent 35 into the contralateral iliac artery 20 (for the second asymmetric stent 36, the lip 66 may protrude into the ipsilateral iliac artery 18). It is contemplated that the lip 66 may be positioned at a portion of or around the entire intermediate opening 43. For example, the lip 66 may be positioned at a location that engages the carina 14 when deployed to provide structural support at the carina 14.8787-25

[0112] The radial support portion may form the skeleton of the remaining portions of the intermediate region 40. The radial support portion may include first, second, and third linearly repeating patterns 70, 72, 74 that flank the opening and lip portions of the intermediate region 40. Similar to the aorta portion rings 56 and the iliac portion rings 62. For example, the first, second, and third linearly repeating patterns 70, 72, 74 may have a “Z” or zig-zag pattern or may be arranged in a “sinusoidal” repeating triangle pattern, diamond pattern, or other linear pattern known in stent designs. In addition, first, second, and third linearly repeating patterns 70, 72, 74 provide support by pressing against the arterial walls located laterally opposite to and laterally proximal to the carina 14.

[0113] The first linearly repeating pattern 70 may be located adjacent to the iliac portion 39 and may be attached to one of the iliac portion rings 62 by a pair of inter sectional bridges 78. The first linearly repeating pattern 70 may also be directly attached to the radially repeating pattern 67 at two locations. The second linearly repeating pattern 72 may be attached to one of the aorta portion rings 56 by a pair of inter sectional bridges 80 and may be attached to the axially extending struts 65. The third linearly repeating pattern 74 may also be directly connected to the radially repeating pattern 67 at two locations and may be attached to the second linearly repeating pattern 72 at inter sectional bridges 78.

[0114] It is contemplated that the scaffolding of the first asymmetric stent 35 may be designed to increase flexibility in the intermediate region 40. In particular, the design of the scaffolding in the intermediate region 40 may allow for a twisting action at the intermediate region 40. That is, the scaffolding design in the intermediate region 40 may allow for the iliac portion 39 and the aorta portion 38 to at least partially rotate around their respective longitudinal axes independently of each other.

[0115] For example, as can be seen in Figs. 3A-3C, the first and third linearly repeating patterns 70, 74 are located adjacent to each other. However,8787-25 there are no inter sectional bridges directly linking the first and third outer linearly repeating patterns 70, 74. The lack of inter sectional bridges between the first and third outer linearly repeating patterns 70, 74 may allow the first and third outer linearly repeating patterns 70, 74 to move independently of each other. Since the first outer linearly repeating pattern 70 is linked to the aorta portion 38 (by way of the second outer linearly repeating pattern 72) and the third outer linearly repeating pattern 74 is linked to the iliac portion 39 (by way of the fourth outer linearly repeating pattern 70), the gap between the first and third outer linearly repeating patterns 70, 74 becomes a location at which movement of the aorta portion 38 is at least partially decoupled from the iliac portion 39 to allow one portion of the asymmetric stent 35 to twist relative to the remaining portions of the asymmetric stent 35.

[0116] The first asymmetric stent 35 is configured to transform from a compressed, linear tubular structure to an asymmetric bifurcated structure when the first asymmetric stent 35 is expanded and bent. In the resulting transformation, the diameter of the aorta portion 38 (the main trunk of the bifurcated structure) may be larger than the diameter of the iliac portion 39 and the intermediate opening 43. In addition, the diameters of the iliac portion 39 and the intermediate opening 43 may be the same.

[0117] As shown in Fig. 3A, the first asymmetrical stent 35 may have a length L1 that is 70-80 mm (e.g., about 76 mm or about 76.6 mm). In addition, when in a compressed state, the outer diameter D1 of the aorta portion 38 and the outer diameter D2 of the iliac portion 39 may be between 5.5 and 8 mm (e.g., about 6 mm or about 6.82 mm). When fully expanded, the outer diameter D1 of the aorta portion 38 may be between 12 and 22 mm (.e.g., about 13 mm, about 15 mm, about 17 mm, about 20 mm) and the outer diameter D2 of the iliac portion 39 may be between 8 and 14 mm (e.g., about 8.5 mm, about 10 mm, about 11.5 mm, about 13.5 mm).8787-25

[0118] It is also contemplated that the width W of the flattened scaffolding pattern of the first asymmetrical stent 35 may be between 20 and 25 mm (e.g., about 21 .44 mm). In addition, a thickness of the aorta portion struts 60 may be between 0.15 mm and 0.25 mm (e.g., about 0.19 mm) and a thickness of the intra sectional bridges 58 may be between 0.10 mm and 0.15 mm (e.g., about 0.12 mm). The thickness of the iliac portion struts 62 may be between 0.1 mm and 0.12 mm (e.g., about 0.11 mm) and the thickness of the intra sectional bridges 63 may be between 0.7 mm and 0.10 mm (e.g., about 0.08 mm).

[0119] Once the first asymmetric stent 35 is fully deployed and expanded, the intermediate opening 43 is large enough to receive the aorta portion 44 of the second asymmetric stent 36 and allow for a full flow of fluid (e.g., blood) through the second asymmetric stent 36. If the first asymmetric stent 35 is deployed after the second asymmetric stent 36 and is received within the second asymmetric stent 36, the intermediate opening 43 may be large enough for the rim of the intermediate opening 43 to abut against the inner walls of the second asymmetric stent 36 and allow for a full flow of fluid (e.g., blood) that is approximately equal between the two limbs.

[0120] As discussed above, the scaffolding or skeleton of the first asymmetric stent 35 in the aorta portion 38 and the iliac portion 39 is comprised of linearly repeating patterns that form rings when rolled up into the final form or cut out of a tube or woven from a wire. However, when in the flattened form, the scaffolding or skeleton in the intermediate region 40 is comprised of a hybrid pattern having a radially repeating pattern 67 that repeats around a central linearly repeating pattern 68 and is flanked by a first outer linearly repeating pattern 70, a second outer linearly repeating pattern 72, and a third outer linearly repeating pattern 74 that is between the first and second outer linearly repeating patterns 70, 72.8787-25

[0121] In one exemplary configuration, the radially repeating pattern 67, the central linearly repeating pattern 68, and the intermediate opening 43 are located in a central part of the intermediate region 40 and are flanked by the first, second, and third outer linearly repeating patterns 70, 72, 74. The radially repeating pattern 67 is adjacent to the iliac portion 39 and the intermediate opening 43 is adjacent to the aorta portion 38.

[0122] When the pattern is in a flattened state, a space L5 between the closest iliac portion ring 62 and the first linearly repeating pattern 70 may be between 2.0 and 3.0 mm (e.g., about 2.9 mm), a space L6 between the first linearly repeating pattern 70 and the third linearly repeating patter 74 may be between 3.0 and 4.0 mm (e.g., about 3.6 mm), and a space L7 between the second linearly repeating pattern 72 and the third linearly repeating pattern 74 may be between 2.0 and 3.0 mm (e.g., 2.8 mm). It is contemplated that the spaces may increase or decrease in size as the first asymmetric stent is bent or flexed.

[0123] It is contemplated that the scaffolding may also include a plurality of radiopaque (RO) markers 86 to help align the first asymmetric stent 35 during implantation. The RO markers 86 may be positioned in eyelets in the vertices of the linearly repeating pattern of the most distal aorta portion ring 56 and the most proximal iliac portion ring 62 and on the patterns forming the lip 66. In the context of the RO markers 86, proximal indicates closer to the hand of the operator that holds the catheter and distal indicates further away from the hand of the operator that holds the catheter. The aorta portion 38 and the iliac portion 39 may each include three RO markers 86. The RO markers 86 in the aorta portion 38 may indicate the location of the distal edge of the aorta portion 38, while the RO markers 86 in the iliac portion 39 may indicate the location of the proximal edge of the iliac portion 39.8787-25

[0124] The intermediate region 40 may also include a plurality of RO markers 86. In particular, the RO markers 86 in the central region may be positioned on a rim of the intermediate opening 43. In the exemplary embodiment illustrated in Figs. 3A and 3B, RO markers 86 may be placed at a vertex of the pattern in the aorta portion ring 56 forming part of the rim of the intermediate opening 43. Each of the axially extending struts 65 may also include RO markers 86 and a distance between such RO markers 86 may be about 6.6 mm. Also, the radially repeating pattern 67 may include two RO markers 86 on an opposite side of the intermediate opening 43 from the RO marker 86 on the aorta portion ring 56. This way, a ring of RO markers 86 may surround the intermediate opening 43 to transmit the location and orientation of the intermediate opening 43 during installation (e.g., whether the intermediate opening 43 faces the other iliac artery). In addition, the RO markers 86 on the radially repeating pattern 67 may be located to indicate the position of the lower portion of the intermediate opening 43 relative to the carina 14.

[0125] It is contemplated that the RO markers 86 may be placed on a base side of the lip 66 (the side of the lip 66 that forms the pivot point when the lip 66 pivots radially outward in response to the asymmetric stent 35 being expanded and / or bent) and / or a distal side of the lip 66 (the side of the lip 66 that is opposite the base side and forms at least part of the rim of the intermediate opening 43).

[0126] The distance L2 from the RO marker 86 in the aorta portion ring 56 forming the rim of the intermediate opening 43 and the lip 66 may be 12-14 mm (e.g. about 13 mm or about 13.4 mm). In addition, a length L3 of the aorta portion 38 from the intermediate region 40 to the end of the stent is 20-30 mm (e.g., about 29 mm or about 29.9 mm). Also, a length L4 of the iliac portion 39 from the intermediate opening 43 to the end of the stent is 30-40 mm (e.g., about 33 mm or about 33.3 mm).8787-25

[0127] When the first asymmetric stent 35 is in a compressed state, a distance W1 between the RO markers 86 on the lateral sides of the rim of the intermediate opening 43 may be between 6 mm and 7 mm (e.g., 6.6 mm). In addition, a minimum distance W2 between the “S” shaped portions of the extending struts 65 may be between 4.0 mm and 5.0 mm (e.g., 4.4 mm). The minimum distance W2 may be 18-25% (e.g., about 20%) of the total circumference of the aorta portion 38 regardless of whether the asymmetric stent 35 is fully compressed or fully expanded. In addition, a length L2 of the intermediate opening 43 in the axial direction may be 50-75% of the total circumference of the aorta portion 38 when the first asymmetric stent 35 is fully compressed and / or when the first asymmetric stent 35 is fully expanded. In addition, the length L2 may shrink by 5-10% as the first asymmetric stent 35 expands.

[0128] Figs. 3C and 3D illustrate the asymmetric stents 34 of Figs. 3A and 3B with a membrane covering the scaffolding.

[0129] It is contemplated that the first and second asymmetric stents 35, 36 are delivered in the collapsed configuration that is linear, coaxial and symmetric and deployed into the expanded configuration that is non-linear “hockey stick” and asymmetric in relation to the axis of the delivery system. The delivery system includes a tube that has a central lumen for the guidewire that forms an axis of symmetry for the assembly in the collapsed state.

[0130] Figs. 3E-3G illustrate alternative scaffolding patterns in a flattened state. Similar to the pattern illustrated in Fig. 3A, the alternative patterns may include rows or rings 56 of a linearly repeating pattern in the aorta portion 38, rows or rings 62 of a linearly repeating pattern in the iliac portion 39, and a hybrid of radially and linearly repeating patterns in the intermediate region 40. Similar to the scaffolding pattern illustrated in Fig. 3A, the hybrid pattern in the intermediate region 40 facilitates the creation of the opening 43.8787-25

[0131] Figs. 4A-4C show an exemplary system for deploying the stent assembly 34 illustrated in Figs. 2A-2B. The stent assembly 34 may be a selfexpanding system. In addition, for this method, the first and second asymmetric stents 35, 36 are delivered from the iliac arteries against the flow of blood in the vessels.

[0132] The first asymmetric stent 35 may be mounted on a first delivery system and compressed inside a retractable sheath 88. When the sheath 88 is retracted the first asymmetric stent 35 is gradually released and expands to assume the pre-set shape that is slightly larger in diameter than the aorta 12. The deployed first asymmetric stent 35 is apposed against the inner walls of the aorta 12.

[0133] A catheter 90 containing the first asymmetric stent 35 in the compressed state may be deployed through the patient’s ipsilateral iliac artery 18 and then into the patient’s aorta 12. The catheter 90 may include a marker 92 on the sheath 88 of the catheter 90. Additional markers (not shown) may be placed on the walls of the catheter shaft 90 and / or sheath 88 and on the handle (not shown) of the catheter 90.

[0134] The catheter 90 may also include a guidewire (or injection) port 94. The marker 92 and the guidewire port 94 may allow the user to rotationally align the first asymmetric stent 35 so that the intermediate opening 43 faces the contralateral iliac artery 20 and is positioned at the transition between the aorta 12 and the contralateral iliac artery 18. For example, the catheter 90 may be rotated until the marker 92 faces the contralateral side of the aorta-iliac bifurcation region. The catheter 90 may be guided by way of a first guidewire 96 that may traverse the central lumen of the delivery system. In the case of the split sheath (explained later) the delivery system can be rotated with the stent partially deployed.8787-25

[0135] The first asymmetric stent 35 may also include markers 92 in the aorta portion 38 that help align the first asymmetric stent 35 with the contralateral iliac artery 20 so that the intermediate opening 43 faces the correct direction. In addition, at least some of the stent markers 92 may be located adjacent to the intermediate opening 43 so that when the marker 92 is adjacent to the transition between the aorta 12 and the contralateral iliac artery 20, the sheath 88 of the catheter 90 may be retracted to deploy the first asymmetric stent 35. In this configuration, the first asymmetric stent 35 may be self-expanding.

[0136] It is contemplated that markers can be placed on the opposing sides of the first asymmetric stent 35. When the first asymmetric stent 35 is in the desired alignment, the markers may overlap from a viewing perspective, which indicates that it is safe to deploy the first asymmetric stent 35. Aligning the markers allows for the deployment of the nested stent assembly without misalignment, which could lead to a jailed blood vessel and failure to create an equal blood flow to both legs.

[0137] Fig. 4B shows the first asymmetric stent 35 in the partially deployed configuration. If the alignment of the first asymmetric stent 35 is not correct, the first asymmetric stent 35 can be retracted back into the sheath 88 by advancing the sheath 88 and the first asymmetric stent 35 can be redeployed. The system of markers and the optional second guidewire 100 act together to ensure that the first asymmetric stent 35 is in the right rotational and longitudinal position. After the aorta portion 38 of the first asymmetric stent 35 is deployed, the sheath 88 can be retracted further to release the iliac portion 39 of the first asymmetric stent 35. Afterward, the delivery system can be removed.

[0138] The sheath 88 illustrated by Fig 4A and 4B may be retracted, i.e. moved in a proximal direction, to enable the first asymmetric stent 35 to expand by manually grasping a pullback handle of the delivery tool (not shown). When the sheath 88 is retracted a distal end region of the first asymmetric stent 35 is8787-25 exposed first, as the sheath 88 continues to be retracted the intermediate region 40 of the first asymmetric stent 35 becomes exposed and finally a proximal region of the first asymmetric stent 35 is exposed so that the first asymmetric stent 35 is fully deployed in the aorta-iliac bifurcation region 10.

[0139] Alternatively, the first asymmetric stent 35 may be initially constrained from fully expanding (through suture or other means) and may be initially prevented from full deployment to allow the first asymmetric stent 35 to be repositioned or recaptured until the first asymmetric stent 35 is in the desired position. When in the desired position, the suture can be cut resulting in full deployment.

[0140] Fig. 4C illustrates the deployment of the second asymmetric stent 36 nested inside the first asymmetric stent 35. Once the first asymmetric stent 35 is fully deployed within the aorta 12 and the ipsilateral iliac artery 18 and oriented so that the intermediate opening 43 of the first asymmetric stent 35 is positioned to open toward the contralateral iliac artery 20 (as per Figure 4A-B), a second catheter 102 may be inserted through the contralateral iliac artery 20 and into the aorta 12.

[0141] The catheter 102 may include a marker 98 on the surface of the catheter 102 or on a wall of the central lumen of the catheter 102. The catheter 102 may also include a guidewire (or injection) port 104. The second guidewire 100 can be inserted in an additional lumen inside the sheath 106 alongside the collapsed and compressed second asymmetric stent 36. The marker 98 and the guidewire port 104 may allow the user to rotationally align the second asymmetric stent 36 so that the intermediate opening 54 faces the ipsilateral iliac artery 18 and is positioned at the transition between the aorta 12 and the ipsilateral iliac artery 18. For example, the catheter 102 may be rotated until the marker 98 faces the ipsilateral side of the aorta-iliac bifurcation region 10. The8787-25 catheter 102 may be guided by way of the second guidewire 100 to assist radial orientation.

[0142] The second asymmetric stent 36 may also include markers 98 in the aorta portion 44 that help align the second asymmetric stent 36 with the ipsilateral iliac artery 18 so that the intermediate opening 54 faces the correct direction. In addition, a marker 98 may be located adjacent to the intermediate opening 54 so that when the marker 98 is adjacent to the transition between the aorta 12 and the ipsilateral iliac artery 18, the sheath 106 of the catheter 102 may be retracted to deploy the second asymmetric stent 36. In this configuration, the second asymmetric stent 36 may be self-expanding and deployed inside of the first asymmetric stent 35 in the nested assembly configuration forming in combination a desired anatomically correct inverted Y-shaped tubular scaffolding inside the aortic bifurcation.

[0143] The split sleeve deployment assembly and method described below and in Figs. 5A-8B allows the intermediate regions 40, 48 of the first and second asymmetric stents 35, 36 to be partially deployed first before any other portion of the stents are deployed. Figs. 5A-5D illustrate the deployment of the first asymmetric stent 35 using the split sleeve deployment system.

[0144] As illustrated in Fig. 5A, the first asymmetric stent 35 is delivered and deployed using a delivery system that consists at a minimum of a catheter core 110 (catheter), a laterally movable first sleave (proximal sheath) 112, a second sleeve (distal sheath) 114, a guide wire 116 and a stent release mechanism (see Figs. 8A and 8B). In the compressed state, the first asymmetric stent 35 is wrapped (crimped) tightly around the core and contained within the first and second sheaths 112, 114.

[0145] When the first asymmetric stent 35 is initially the first and second sleeves 112, 114 either abut each other or overlap each other so that no part of the first asymmetric stent is exposed at this stage. Initially, the catheter 110 is8787-25 guided through the ipsilateral iliac artery 18 and into the aorta 12 along the guidewire 116.

[0146] While the first asymmetric stent 35 is partially deployed, the surgeon is able to move the delivery system laterally through the blood vessel and rotate the first and second sleeves 112, 114 and the first asymmetric stent 35. The surgeon can use markers on the sleeves or other methods to estimate how far into the vessel the first asymmetric stent 35 has traveled. When the intermediate region 40 of the first asymmetric stent 35 is estimated to be in the oval transverse section 16 of the aorta-iliac bifurcation region 10.

[0147] In Fig. 5B, the intermediate region 40 of the first asymmetric stent 35 is estimated to be in the oval transverse section 16 of the aorta-iliac bifurcation region 10. Accordingly, the first asymmetric stent 35 is partially deployed by beginning to separate the first and second sleeves 112, 114 from each other.Once part of the first asymmetric stent 35 is uncovered, markers on the first asymmetric stent 35 may become visible using medical imaging instruments. This visibility of the uncovered portion of the first asymmetrical stent 35 aids the surgeon in determining when the first asymmetrical stent 35 is properly laterally positioned at the iliac-aorta bifurcation region and when the intermediate opening 43 in the first asymmetrical stent 35 is aligned with the opening to the other iliac artery.

[0148] The visibility of the first asymmetrical stent 35 may be enhanced by radiopaque markers that can be dots, stripes and other configurations that assist orientation in two-dimensional X ray projection. While the first asymmetrical stent 35 is partially deployed, the surgeon may move the first asymmetrical stent 35 and first and second sleeves 112, 114 laterally in the iliac artery 18 and aorta 12 to position the intermediate region 40 of the first asymmetrical stent 35 at the iliac-aorta bifurcation region. The surgeon may also rotate the first asymmetrical stent 35 and sleeves 112, 114 to position the exposed intermediate opening 40 in8787-25 the first asymmetrical stent 35 to face the opening to the other iliac artery. Once the first asymmetrical stent 35 is properly positioned, first and second sleeves 112, 114 are moved in opposite lateral directions to slide off from the first asymmetrical stent 35. The first asymmetrical stent 35 expands when the sections of the first and second sleeves 112, 114 are off the first asymmetrical stent 35.

[0149] As illustrated in Figure 5E, the surgeon can reposition the first asymmetric stent 35 within the iliac artery, aorta and iliac aortic bifurcation because the first asymmetric stent 35 is only partially deployed and has not expanded to its full outer dimensions and may not be yet bracing or biasing against the opposing inner walls of the artery. The fully expanded first asymmetric stent 35 is designed to be slightly oversized, meaning the fully expanded diameter is slightly larger than the diameter of the inner lumen of the “healthy” artery. Thus, the stenosed lumen is restored to close to natural caliber. While partially deployed the first asymmetric stent 35 has an outer dimension, e.g., diameter, narrower than the diameter of the blood vessel. The partially deployed first asymmetric stent 35 is not biased against the walls of the blood vessel. The catheter 110 can be moved laterally by the surgeon within the blood vessel and may be rotated. Lateral movements may be made by the surgeon pushing or pulling the proximal end of the catheter 110. Rotational movement may be performed by the surgeon twisting the proximal end of the catheter.Various degrees of automation, such as robotic manipulation of the catheter 110 are anticipated with the advancement of technology.

[0150] When the surgeon confirms that the stent is properly positioned laterally and rotationally at the iliac aortic bifurcation, the surgeon manipulates catheter 110 to advance the sections of the sleeve along the catheter 110 so that the sections 114, 112 no longer cover the first asymmetric stent 35 and fully release the first asymmetric stent 35 from the sleeve 121 . Once released and the8787-25 sections 114, 112 of the sleeve 121 are fully moved away from the first asymmetric stent 35, the first asymmetric stent 35 automatically expands due to its internal biasing forces and / or balloons underlying the stent are fully expanded to expand and deploy the sent to its final dimensions. An additional step of “post dilation” may be performed.

[0151] Advancing of the catheter 110 with the split sleeve 121 and the first asymmetric stent 35 and positioning the assembly at the aorta iliac bifurcation may be performed by a surgeon manipulating a handle 132 at the proximal end of catheter 110, such as the catheter 110 shown in Figure 5E. Markers on the first asymmetric stent 35, such as radiopaque markers and gold tags, are visible in X- ray images, e.g., real time fluoroscopy or CT (computed tomography) scanning. The images are captured in real-time by an imaging device (illustrated by an eye) that may be a commonly used fluoroscopy C-arm device, X-ray device, ultrasound or other medical imaging device configured to generate real time images of a blood vessel in an alive patient.

[0152] The commonly used C-Arm for imaging fluoroscopy can be manipulated to create orthogonal planes as well known in the art of angiography. These orthogonal planes allow the alignment of markers where for example one marker disappearing behind another may signal the correct alignment of the first asymmetric stent in the partially deployed state.

[0153] Figs 6A-6F illustrate the deployment of the first asymmetric stent 35 into the aorta-iliac bifurcation region 10. Fig. 6A illustrates a first guidewire 120 and a buddy guidewire 118 being inserted through the ipsilateral iliac artery 18 and the contralateral iliac artery 20 and through the aorta 12. It is contemplated that the buddy wire 118 may be omitted and only the first guidewire 120 is employed to deploy the first asymmetric stent 35.

[0154] In Fig. 6B, the first asymmetric stent 35 within a split sleeve 121 is advanced along the guidewire 120 through the contralateral iliac artery 20 and8787-25 into the aorta 12. The first asymmetric stent 35 is held in a collapsed mode around a catheter 123 by the split sleeve 121 . The split sleeve 121 covers the entirety of the first asymmetric stent 35 and compresses the first asymmetric stent 35. The catheter 123 with the first asymmetric stent 35 and the split sleeve 121 are advanced along the guidewire 120 until the split sleeve 121 and the first asymmetric stent 35 are positioned at the iliac aorta bifurcation.

[0155] Figs. 6C and 6D show the split sleeve 121 and the first asymmetric stent 35 being aligned with the bifurcation. Aligning the catheter 123 to position the first asymmetric stent 35 and the split sleeve 121 at the aorta iliac bifurcation may be performed by a surgeon manipulating a handle (not shown) at the proximal end of catheter 123. Markers on the first asymmetric stent 35, such as radiopaque markers and gold tags, are visible in X-ray images, e.g., real time fluoroscopy or CT (computed tomography) scanning. The images are captured in real-time by an imaging device that may be a commonly used fluoroscopy C-arm device, X-ray device, ultrasound or other medical imaging device configured to generate real time images of a blood vessel in an alive patient. Images of the stent and sleeve assembly and markers on the stent aid the surgeon in manipulating the distal end of the catheter 123 to position Images of the first asymmetric stent 35 and split sleeve 121 enable the surgeon to see where the first asymmetric stent 35 and split sleeve 121 are relative to the iliac aorta bifurcation.

[0156] The markers, especially those at the intermediate opening 43 of the first asymmetric stent 35, appear on the images and indicate that the intermediate opening 43 of the first asymmetric stent 35 is expanding as the split sleeve 121 is opened. The split sleeve 121 may be opened by moving the proximal and distal sleeves 122, 124 away from each other (or moving only one of the proximal and distal sleeves 122, 124, while the other one of the sleeves remains stationary). The markers appearing on the images may also indicate8787-25 whether the intermediate opening 43 of the first asymmetric stent 35 is facing the opening to the ipsilateral iliac artery18. As illustrated in Fig. 6E, the catheter 123 may be moved axially and rotated radially so that the intermediate opening 43 is aligned with the opening to the ipsilateral iliac artery 18.

[0157] Figs 7A-7F illustrate the deployment of the second asymmetric stent 36 into the aorta-iliac bifurcation region 10. Fig. 7A illustrates a second guidewire 126 inserted through the ipsilateral iliac artery 18 and a buddy wire 127 inserted through the contralateral iliac artery 20 and through the aorta 12. It is contemplated that the buddy wire 127 may be omitted and only the second guidewire 126 is employed to deploy the second asymmetric stent 36.

[0158] In Fig. 7B, the second asymmetric stent 36 within a split sleeve is advanced along the guidewire 125 through the ipsilateral iliac artery 18 and into the aorta 12. The second asymmetric stent 36 is held in a collapsed mode around a catheter by the split sleeve. The split sleeve covers the entirety of the second asymmetric stent 36 and compresses the second asymmetric stent 36. The catheter with the second asymmetric stent 36 and the split sleeve are advanced along the guidewire 125 until the split sleeve and the second asymmetric stent 36 are positioned at the iliac aorta bifurcation.

[0159] Figs. 7C and 7D show the split sleeve and the second asymmetric stent 36 being aligned with the bifurcation. Aligning the catheter to position the second asymmetric stent 36 and the split sleeve at the aorta iliac bifurcation may be performed by a surgeon manipulating a handle (not shown) at the proximal end of catheter. Markers on the second asymmetric stent 36, such as radiopaque markers and gold tags, are visible in X-ray images, e.g., real time fluoroscopy or CT (computed tomography) scanning. The images are captured in real-time by an imaging device that may be a commonly used fluoroscopy C-arm device, X- ray device, ultrasound or other medical imaging device configured to generate real time images of a blood vessel in an alive patient. Images of the stent and8787-25 sleeve assembly and markers on the stent aid the surgeon in manipulating the distal end of the catheter to position Images of the second asymmetric stent 36 and split sleeve enable the surgeon to see where the second asymmetric stent 36 and split sleeve are relative to the iliac aorta bifurcation.

[0160] The markers, especially those at the intermediate opening 54 of the second asymmetric stent 36, appear on the images and indicate that the intermediate opening 54 of the second asymmetric stent 36 is expanding as the split sleeve is opened. The split sleeve may be opened by moving the proximal and distal sleeves 122, 124 away from each other (or moving only one of the proximal and distal sleeves 122, 124, while the other one of the sleeves remains stationary). The markers appearing on the images may also indicate whether the intermediate opening 54 of the second asymmetric stent 36 is facing the opening to the ipsilateral iliac artery 18. As illustrated in Fig. 7E, the catheter 124 may be moved axially and rotated radially so that the intermediate opening 54 is aligned with the opening to the ipsilateral iliac artery 18.

[0161] Once the first asymmetric stent 35 is properly positioned and deployed, the buddy wire 127 may be retracted through the ipsilateral iliac artery 18, and the split sleeve may be retracted through the first and second openings 50, 52 of the second asymmetric stent 36.

[0162] The split sleeve is split into a distal cylindrical section 122 and a proximal cylindrical section 124. The ends of the cylindrical sections 122, 124 overlap or abut each other. The distal cylindrical section 122 is advanced distally towards the distal end of the split sleeve. The proximal cylindrical section 124 is retracted toward the proximal end of the split sleeve. This opens a window at which the intermediate region 40 of the first asymmetric stent 35 becomes exposed.

[0163] It is contemplated that both the distal cylindrical section 122 and the proximal cylindrical section 124 can be advanced and retracted simultaneously8787-25 through the same mechanism or different mechanisms. Alternatively, the distal cylindrical section 122 and the proximal cylindrical section 124 can be advanced and retracted at different times. In yet another configuration, only one of the distal cylindrical section 122 and the proximal cylindrical section 124 can be laterally moved.

[0164] Figs. 8A and 8B shows a cross-sectional view of a mechanism to deploy the split sleeve. The mechanism partially resides in the handle 126. The mechanism may include a first spindle 134 and a second spindle 136 that are aligned along the same rotatable axis. A first wire 130 may be wound around the first spindle 134, and a second wire 132 may be wound around the second spindle 136. The first and second spindles 134, 136 may be wound in opposite directions (i.e., clockwise and counterclockwise) so that if they spin at the same time, one wire will be unwound and the other wire will be wound.

[0165] The handle 126 may include a knob 128 that is attached to the first and second spindles 134, 136 by way of a common rod. Accordingly, rotating the knob 128 clockwise will cause the first and second spindles 134, 136 to rotate in a clockwise direction. Rotating the knob 128 in a counterclockwise direction will cause the first and second spindles 134, 136 to also rotate in a counterclockwise direction, The first and second wires 130, 132 may be respectively connected to the proximal sleeve 124 and the distal sleeve 122.

[0166] Rotating the first and second spindles 134, 136 in a first direction may cause the first wire 130 to wind onto the first spindle 134 and pull the proximal sleeve 124 toward the handle in a proximal direction. At the same time, the second wire 132 may unwind from the second spindle 136 and push the distal sleeve 122 away from the handle in the distal direction, thereby creating an opening for the stent 35 to deploy. Reversing the direction in which the knob 128 is rotated may cause the first and second wires 130, 132 to reverse their direction and close the gap between them.8787-25

[0167] It is contemplated that either of the distal and proximal sleeves 122, 124 may be stationary and not connected to a spindle so that only one of the distal and proximal sleeves 122, 124 may be movable by rotating the knob 128.

[0168] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or "comprising" do not exclude other elements or steps, the terms "a" or "one" do not exclude a plural number, and the term “or” means either or both, unless this application states otherwise. Also, the terms “approximately” and “substantially” encompass a range of plus or minus 15%. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise.EMBODIMENTS

[0169] The following is a non-limiting list of exemplary embodiments according to the present disclosure.

[0170] Embodiment 1 . A stent assembly configured to maintain a lumen in a bifurcated vessel, the stent assembly comprising: a first stent with an intermediate opening on a side of the first stent; and a second stent with an intermediate opening on a side of the second stent, wherein a portion of the second stent with the second stent intermediate opening is configured to be nested within the first stent.

[0171] Embodiment 2. The stent assembly of embodiment 1 , wherein the first stent has a first opening at a first end, a second opening at a second end, and wherein the first stent intermediate opening is on the side of the first stent8787-25 between the first and second openings of the same first stent; and wherein the second stent has a first opening at a first end, a second opening at a second end, and wherein the second stent intermediate opening is on the side of the second stent between the first and second openings of the same second stent.

[0172] Embodiment 3. The stent assembly of embodiment 1 or 2, said portion of the second stent provided with the second stent intermediate opening is configured to be nested within the first stent at least when the first stent is in its fully expanded configuration.

[0173] Embodiment 4. The stent assembly of any one of the preceding embodiments, wherein the second stent is configured to extend through the intermediate opening of the first stent, in particular wherein the second stent is configured to extend through the intermediate opening of the first stent at least when the first stent is in its fully expanded configuration.

[0174] Embodiment 5. The stent assembly of any one of the preceding embodiments, wherein the intermediate opening in the first stent is configured to receive the second stent, in particular wherein the intermediate opening in the first stent is configured to receive the second stent at least when the first stent is in its fully expanded configuration.

[0175] Embodiment 6. The stent assembly of embodiments 2 and 5, wherein when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent, the intermediate opening in the second stent is configured to align with the first opening in the first stent and allow fluid to flow through from the first opening to the second opening of the first stent.

[0176] Embodiment 7. The stent assembly of any one of the preceding embodiments, wherein the first and second stents are identical.

[0177] Embodiment 8. The stent assembly of any one of the preceding embodiments, wherein the stent assembly is configured to maintain a lumen in8787-25 an aorta-iliac bifurcation region (10), in particular at least when the first and second stents are in their fully expanded configuration; and wherein each of the first and second stents comprises an aorta portion configured to be positioned within an aorta and an iliac portion configured to be positioned within an iliac artery.

[0178] Embodiment 9. The stent assembly of embodiment 8, wherein, for each of the first and second stents in their fully expanded configuration, a maximum radial size, in particular a diameter, of the aorta portion is larger than a maximum radial size, in particular a diameter, of the iliac portion.

[0179] Embodiment 10. The stent assembly of any one of embodiments 8 to 9, wherein the intermediate opening in the first stent is configured to be aligned with the iliac portion of the second stent.

[0180] Embodiment 11 . The stent assembly of any one of embodiments 8 to 10, wherein the intermediate opening in the second stent is configured to be aligned with the iliac portion of the first stent.

[0181] Embodiment 12. The stent assembly of any one of the preceding embodiments, wherein the first stent is asymmetric at least when in its fully expanded configuration; and wherein the second stent is asymmetric at least when in its fully expanded configuration.

[0182] Embodiment 13. The stent assembly of any one of the preceding embodiments, wherein the first and second stents are configured such that: when the first and second stents are coupled together with the second stent intermediate opening nested within the first stent, and when the first and second stents are in their fully expanded configuration in a vessel lumen region that changes transverse dimensions and shape, optionally in a bifurcation region, said first and second stents conform to and scaffold inner walls of said vessel lumen region.8787-25

[0183] Embodiment 14. The stent assembly of any one of the preceding embodiments, wherein each of the first and second stents is a partially covered stent or a totally covered stent.

[0184] Embodiment 15. The stent assembly of any one of the preceding embodiments, wherein each of the first and second stents comprises a scaffolding and a covering, optionally a membrane covering, wherein the scaffolding is partially or completely enclosed by the covering.

[0185] Embodiment 16. The stent assembly of embodiment 15, wherein each of the first and second stents is completely covered by the covering, optionally wherein the covering is a bio-compatible covering.

[0186] Embodiment 17. The stent assembly of any one of the preceding two embodiments, wherein the covering is a membrane covering, optionally a wherein the membrane covering is made of plastic, more optionally made from EPTFE or TPU.

[0187] Embodiment 18. The stent assembly of any one of the preceding embodiments, wherein the first and second stent intermediate openings are configured to be positioned to face opposite lateral directions; in particular wherein the first and second stent intermediate openings are configured to be positioned to face opposite lateral directions when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent.

[0188] Embodiment 19. The stent assembly of any one of the preceding embodiments, wherein the first and second stents are configured to be positioned in orientations that laterally mirror each other; in particular wherein the first and second stents are configured to be positioned in orientations that laterally mirror each other when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent.8787-25

[0189] Embodiment 20. The stent assembly of any one of the preceding embodiments, wherein the first stent comprises a wider portion, optionally having a respective first diameter, and a narrower portion, optionally having a respective second diameter; and wherein the second stent comprises a wider portion, optionally having a respective first diameter, and a narrower portion, optionally having a respective second diameter.

[0190] Embodiment 21 . The stent assembly of embodiment 20, wherein said portion of the second stent which is configured to be nested within the first stent corresponds to the wider portion of the second stent, and wherein said wider portion of the second stent is configured to be nested within the wider portion of the first stent.

[0191] Embodiment 22. The stent assembly of any one of embodiments 20 to 21 , wherein when the first and second stents are in their fully expanded configuration and said wider portion of the second stent is nested within the first stent, the wider portion of the first stent is configured to extend beyond the wider portion of the second stent.

[0192] Embodiment 23. The stent assembly of any one of embodiments 20 to 22, wherein when the first and second stents are in their fully expanded configuration and said wider portion of the second stent is nested within the first stent, the first stent intermediate opening is configured to be aligned with the narrower portion of the second stent and the second stent intermediate opening is configured to be aligned with the narrower portion of the first stent.

[0193] Embodiment 24. The stent assembly of any one of the preceding embodiments 19 to 23, wherein when the first and second stents are in their fully expanded configuration and said wider portion of the second stent is nested within the first stent, the wider portion of the first stent is configured to completely surround and embrace the wider portion of the second stent, optionally wherein8787-25 the wider portion of the first stent is configured to be coaxial with the wider portion of the second stent.

[0194] Embodiment 25. The stent assembly of any one of embodiments 19 to 24, wherein when the first and second stents are in their fully expanded configuration and said wider portion of the second stent is nested within the first stent, a radially external surface of the wider portion of the second stent is configured to overlap and come into contact with a radially internal surface of the wider portion of the first stent along an entire circumferential development of the wider portion of the second stent.

[0195] Embodiment 26. The stent assembly of any one of embodiments 19 to 25, wherein when the first and second stents are in their fully expanded configuration and the wider portion of the second stent is nested within the first stent, a radially external surface of the wider portion of the second stent is configured to overlap and come into contact with a radially internal surface of the wider portion of the first stent forming a mutual contact surface which develops around the wider portion of the second stent and extends axially until the opening of the wider portion of the same second stent.

[0196] Embodiment 27. The stent assembly of any one of the preceding embodiments, in combination with embodiment 15, wherein the first and second stents are configured such that: when the first and second stents are coupled together with the second stent portion nested within the first stent and when the first and second stents are in their fully expanded configuration in a vessel lumen region, optionally in a bifurcation region, the first and second stents present overlapping stent coverings.

[0197] Embodiment 28. The stent assembly of embodiment 27, wherein the overlapping stent coverings are configured for providing a seal against leaks outside of the stent assembly through the scaffolding.8787-25

[0198] Embodiment 29. The stent assembly of any one of the preceding embodiments, wherein the first stent is expandable from a collapsed configuration to a / the fully expanded configuration, and wherein the second stent is expandable from a collapsed configuration to a / the fully expanded configuration.

[0199] Embodiment 30. The stent assembly of embodiment 29, wherein a maximum radial size of a cross section of at least a longitudinal portion of the first stent, optionally of the entire first stent, is greater when the first stent is in its fully expanded configuration than when the first stent is in the collapsed configuration; and wherein a maximum radial size of a cross section of at least a longitudinal portion of the second stent, optionally of the entire second stent, is greater when the second stent is in its fully expanded configuration than when the second stent is in the collapsed configuration.

[0200] Embodiment 31 . The stent assembly of embodiment 29 or 30, when combined with embodiment 8, wherein a maximum radial size, in particular a diameter, of a cross section of the aorta portion of the first stent is greater when the first stent is in its fully expanded configuration than when the first stent is in the collapsed configuration; and wherein a maximum radial size, in particular a diameter, of a cross section the aorta portion of the second stent is greater when the second stent is in its fully expanded configuration than when the second stent is in the collapsed configuration.

[0201] Embodiment 32. The stent assembly of embodiment 29 or 30 or 31 , when combined with embodiment 8, wherein a maximum radial size of a cross section of the iliac portion of the first stent is greater when the first stent is in its fully expanded configuration than when the first stent is in the collapsed configuration; and wherein a maximum radial size of a cross section the iliac portion of the second stent is greater when the second stent is in its fully8787-25 expanded configuration than when the second stent is in the collapsed configuration.

[0202] Embodiment 33. The stent assembly of any one of the preceding embodiments, wherein the first and second stents are self-expanding; or wherein the first and second stents are expanded by deploying and inflating corresponding balloons.

[0203] Embodiment 34. The stent assembly of any one of the preceding embodiments, when combined with embodiment 29, wherein the first stent is configurable in: a delivery state, in which the first stent takes the collapsed configuration, optionally a collapsed linear and coaxial configuration, and a fully deployed state, in which the first stent takes the fully expanded configuration; and / or wherein the second stent is configurable in: a delivery state, in which the second stent takes the collapsed configuration, optionally a collapsed linear and coaxial configuration, and a fully deployed state, in which the second stent takes the fully expanded configuration.

[0204] Embodiment 35. The stent assembly of embodiment 34, wherein the first stent is configurable in a partially deployed state, in which the first stent takes an expanded configuration which is intermediate between the collapsed configuration and the fully expanded configuration; and / or wherein the second stent is configurable in a partially deployed state, in which the second stent takes an expanded configuration which is intermediate between the collapsed configuration and the fully expanded configuration.

[0205] Embodiment 36. The stent assembly according to embodiment 34 or 35, wherein with the first stent in the deployed state or in the partially deployed state, the second stent can be inserted, deployed and, optionally, expanded, through the first stent side opening.8787-25

[0206] Embodiment 37. The stent assembly of embodiment 34 or 35 or 36, wherein the first and second stents in the delivery state are configured to be delivered to an aorto-iliac bifurcation.

[0207] Embodiment 38. The stent assembly of any one of embodiments 34 to 37, wherein for each of the first and second stents, the intermediate opening is a slit or punched hole that is more than 50% of the circumference of the stent when the stent is in the delivery state.

[0208] Embodiment 39. The stent assembly of embodiment 38, wherein the first stent is configured to be oriented and deployed so that the slit or punched hole becomes the intermediate opening and is aligned with the contralateral iliac ostium.

[0209] Embodiment 40. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein each of the first and second stents has the aorta portion which is configured to be shape set to a larger maximum radial size, in particular a larger diameter, than the iliac portion.

[0210] Embodiment 41 . The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein, wherein each of the first and second stents has an intermediate portion connecting the aorta portion to the iliac portion.

[0211] Embodiment 42. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein the cross-sectional area of each of the first and second stents is greater in the aorta portion than in the iliac portion.

[0212] Embodiment 43. The stent assembly of any one of the preceding embodiments, in combination with embodiment 41 , wherein the cross-sectional area of the intermediate portion of each of the first and second stents increases from the aorta portion toward the iliac portion.8787-25

[0213] Embodiment 44. The stent assembly of any one of the preceding embodiments, in combination with embodiments 2, 8 and 41 , wherein each of the first and second stents has the first opening at the end of the aorta portion, the second opening at the end of the iliac portion, and the intermediate opening located at the intermediate portion between the first and second openings.

[0214] Embodiment 45. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8 and 41 , wherein the aorta portion and the intermediate portion of the second stent are configured to be positioned entirely within the aorta portion and intermediate portion of the first stent so that the second stent is partially nested within the first stent.

[0215] Embodiment 46. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein with the second stent inserted through the first stent intermediate opening and expanded inside the first stent, the aorta portions of the two stents are nested and overlap and the iliac portions of the two stents diverge forming an inverted Y-shape scaffolding approximating the aortic bifurcation.

[0216] Embodiment 47. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to extend beyond the aorta portion of the second stent.

[0217] Embodiment 48. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the first stent intermediate opening is configured to be aligned with the iliac portion of the second stent and the second stent intermediate opening is configured to be aligned with the iliac portion of the first stent.8787-25

[0218] Embodiment 49. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to completely surround and embrace the aorta portion of the second stent.

[0219] Embodiment 50. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to be coaxial with the aorta portion of the second stent.

[0220] Embodiment 51 . The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, a radially external surface of the aorta portion of the second stent is configured to overlap with and contact a radially internal surface of the aorta portion of the first stent along an entire circumferential development of the aorta portion of the second stent.

[0221] Embodiment 52. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, a radially external surface of the aorta portion of the second stent is configured to overlap and come into contact with a radially internal surface of the aorta portion of the first stent forming a mutual contact surface which develops around the aorta portion of the second stent and extends axially until the opening of the aorta portion of the same second stent.8787-25

[0222] Embodiment 53. The stent assembly of any one of the preceding embodiments, in combination with embodiments 2, 8, and 41 , wherein the first stent has: the aorta portion with a first diameter, the first opening being an inlet opening located at an end of the aorta portion and configured to receive blood flowing into the first stent; the iliac portion with a second diameter that is smaller than the first diameter, the second opening being a first outlet opening being located at an end of the iliac portion and configured to discharge part of the blood flowing through the first stent; and the intermediate portion connecting the aorta portion to the iliac portion, with the intermediate opening being a second outlet opening positioned in the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the first stent; and wherein the second stent has: the aorta portion with a first diameter, the first opening being an inlet opening located at an end of the aorta portion and configured to receive blood flowing into the second stent; the iliac portion with a second diameter that is smaller than the first diameter, the second opening being a first outlet opening located at an end of the iliac portion and configured to discharge part of the blood flowing through the second stent; and the intermediate portion connecting the aorta portion to the iliac portion, with the intermediate opening being a second outlet opening positioned in the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the second stent.

[0223] Embodiment 54. The stent assembly of embodiment 53, wherein in each of the first and second stents the inlet opening and the second outlet opening are larger than the first outlet opening.

[0224] Embodiment 55. The stent assembly of embodiment 53 or 54, wherein in each of the first and second stents a cross-sectional area of the intermediate portion is varied.8787-25

[0225] Embodiment 56. The stent assembly of embodiment 53 or 54 or 55, wherein in each of the first and second stents cross-sectional areas of the aorta portion and of the iliac portion are constant.

[0226] Embodiment 57. The stent assembly of any one of the preceding embodiments 53 to 56, wherein in each of the first and second stents the shape of the second outlet opening is different from the shape of the first outlet opening and is different from the shape of the inlet opening.

[0227] Embodiment 58. The stent assembly of any one of the preceding embodiments in combination with embodiment 8, wherein each of the first and second stents comprises one or more protruding elements forming a protruding rim at the respective first or second stent intermediate opening, the protruding rim extending around a portion of or the entire perimeter of said respective intermediate opening.

[0228] Embodiment 59. The stent assembly of embodiment 58, wherein when the first and second stents are in their fully expanded configuration: the protruding elements of the rim the first stent are configured to form a respective branch portion with a radially inner surface that surrounds and comes into contact with a mating radially external surface of the iliac portion of the second stent; and the protruding elements of the rim of the second stent are configured to form a respective branch portion with a radially outer surface that is inserted and comes into contact with a mating radially inner surface of the iliac portion of the second stent.

[0229] Embodiment 60. The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein in each of the first and second stents the aorta portion is tubular, and the iliac portion is tubular.

[0230] Embodiment 61 . The stent assembly of any one of the preceding embodiments, in combination with embodiment 8, wherein in each of the first and second stents the iliac portion is configured to pivot relative to the aorta portion8787-25 around a pivotable connection between the aorta portion and the iliac portion, and wherein the intermediate opening is located adjacent to the pivotable connection.

[0231] Embodiment 62. The stent assembly of any one of the preceding embodiments, in combination with one of embodiments 14 to 17 and 27 to 28, wherein in each of the first and second stents the covering has an opening at the intermediate opening.

[0232] Embodiment 63. The stent assembly of any one of the preceding embodiments, wherein each of the first and second stents comprises a plurality of markers, optionally wherein the markers are radiopaque markers, configured to indicate a position of the stent relative to the vessels in which the stent is inserted.

[0233] Embodiment 64. The stent assembly of embodiment 63, in combination with embodiment 58, wherein the plurality of markers includes markers that are positioned adjacent to or at the rim, optionally in correspondence of the one or more protruding elements of the rim, of the respective first or second stent.

[0234] Embodiment 65. The stent assembly of any one of embodiments 63 to 64, wherein in each of the first and second stents the plurality of markers includes markers that are positioned at a proximal end of the iliac portion and at a distal end of the aorta portion.

[0235] Embodiment 66. The stent assembly of any one of the preceding embodiments, wherein one or both the first stent and second stent have an expandable scaffolding and are configured to transform from an unexpanded tubular state to an expanded bifurcated state.

[0236] Embodiment 67. The stent assembly of embodiment 66, wherein one or both the first and second stent comprise: a first tubular section located at a first end of the stent when the stent is in the unexpanded tubular state; a8787-25 second tubular section located at a second opposite end of the stent when the stent is in the unexpanded tubular state; and an intermediate section that intervenes between the first and second tubular sections.

[0237] Embodiment 68. The stent assembly of embodiment 67, wherein in one or both the first and second stent the scaffolding is arranged in a first pattern in the first tubular section, the scaffolding is arranged in a second pattern in the second tubular section that is the same as the first pattern, and the scaffolding is arranged in a third pattern in the intermediate section that is different from the first and second patterns.

[0238] Embodiment 69. The stent assembly of embodiment 67 or 68, wherein in one or both the first and second stent the intermediate section, in particular the third pattern of the intermediate section, includes a gap.

[0239] Embodiment 70. The stent assembly of embodiment 68 or 69, in combination with embodiment 67, wherein in one or both the first and second stent the intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap.

[0240] Embodiment 71 . The stent assembly of embodiment 69 or 70, wherein in one or both the first and second stent the intermediate section is configured so that bending the stent at the intermediate section causes a rim around the gap to outwardly protrude from a radial side of the stent; and / or wherein in one or both the first and second stent a / the rim around the gap is configured to outwardly protrude from a radial side of the stent when the gap increases in size.

[0241] Embodiment 72. The stent assembly of embodiment 69 or 70 or 71 , wherein in one or both the first and second stent the intermediate section, in particular the third pattern of the intermediate section, includes a further gap, wherein the gap and further gap are positioned on opposite sides of the respective stent or of a central longitudinal axis of the respective stent.8787-25

[0242] Embodiment 73. The stent assembly of embodiment 72, wherein in one or both the first and second stent the intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap and decreases the size of the further gap.

[0243] Embodiment 74. The stent assembly of any one of embodiments 67 to 73, when combined with embodiment 8 wherein, in one or both the first and second stent, the expandable scaffolding is configured so that, when the respective stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the first tubular section transforms into the aorta portion with a first maximum radial size, in particular a first diameter, and the second tubular section transforms into the iliac portion with a second maximum radial size, in particular a second diameter, that is less than the first maximum radial size, in particular less than the first diameter.

[0244] Embodiment 75. The stent assembly of any one of embodiments67 to 74, when combined with embodiments 8 and 71 wherein, in one or both the first and second stent, the expandable scaffolding is configured so that, when the respective stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the rim around the gap transforms into a branch portion that is shorter than the iliac portion and has the same maximum radial size, in particular the same diameter, as the iliac portion of the same stent.

[0245] Embodiment 76. The stent assembly of any one of embodiments68 to 75, wherein the first and second patterns comprise a plurality of linear patterns.

[0246] Embodiment 77. The stent assembly of any one of embodiments 68 to 76, wherein the third pattern comprises a radial pattern.

[0247] Embodiment 78. The stent assembly of embodiment 77, wherein the third pattern further comprises a plurality of linear patterns.8787-25

[0248] Embodiment 79. The stent assembly of any one of embodiments 68 to 78, further comprising markers in the scaffolding that are positioned to indicate the location of at least one of a first end of the stent at the first tubular section, a second end of the stent in the second tubular section, of the gap and optionally of the further gap.

[0249] Embodiment 80. The stent assembly of embodiment 79, wherein at least some of the markers are positioned adjacent to the gap and, optionally, adjacent to the further gap.

[0250] Embodiment 81 . The stent assembly of any one of embodiments66 to 80, wherein the stent is configured to transform from a linear tubular structure to an asymmetric bifurcated structure by bending the linear tubular structure at the intermediate section, the asymmetric bifurcated structure having a main trunk and two branches, the branches having different lengths and the main trunk having a greater diameter than the two branches.

[0251] Embodiment 82. The stent assembly of any one of embodiments67 to 81 wherein: the scaffolding in the first tubular section comprises a plurality of linear patterns configured to form a plurality of rings; the scaffolding in the second tubular section comprises a plurality of linear patterns configured to form a plurality of rings; and the scaffolding in the intermediate section comprises a radial pattern.

[0252] Embodiment 83. The stent assembly of any one of embodiments 67 to 82, in combination with embodiment 69, wherein the gap is centrally positioned at the intermediate section.

[0253] Embodiment 84. The stent assembly of any one of embodiments 82 to 83, wherein the scaffolding in the intermediate section further comprises a plurality of linear patterns that are separated from the first and second tubular sections.8787-25

[0254] Embodiment 85. A stent configured to be used as first or second stent in the stent assembly of any one of the preceding embodiments, where in the stent comprises: a first or aorta portion having a first opening configured to receive blood flowing into the stent; a second or iliac portion having a second opening configured to discharge part of the blood flowing through the stent; and an intermediate portion, connecting the first or aorta portion to the second or iliac portion, having an intermediate opening positioned on a side of the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the stent.

[0255] Embodiment 86. The stent of embodiment 85, wherein the stent is expandable, optionally self-expandable, from a collapsed configuration to a fully expanded configuration; optionally wherein the stent is configurable in: a delivery state, in which the stent takes the collapsed configuration, optionally a collapsed linear and coaxial configuration, and a fully deployed state, in which the stent takes the fully expanded configuration.

[0256] Embodiment 87. The stent of embodiment 86, wherein the stent is asymmetric at least in the fully expanded configuration.

[0257] Embodiment 88. The stent of any one of embodiments 86 to 87, wherein at least in the fully expanded configuration: the first or aorta portion has a first maximum radial size, optionally with a first diameter; and the second or iliac portion has a second maximum radial size, optionally a second diameter, that is smaller than first maximum radial size, optionally smaller than the first diameter.

[0258] Embodiment 89. The stent of any one of embodiments 86 to 88, wherein at least in the fully expanded configuration the first opening and the intermediate opening are larger than the second opening.

[0259] Embodiment 90. The stent of any one of embodiments 86 to 89, wherein at least in the fully expanded configuration a cross-sectional area of the8787-25 intermediate portion is varied and / or increases from the first or aorta portion toward the second or iliac portion.

[0260] Embodiment 91 . The stent of any one of embodiments 86 to 90, wherein at least in the fully expanded configuration the cross-sectional areas of the first or aorta portion and of the second or iliac portion are constant.

[0261] Embodiment 92. The stent of any one of embodiments 86 to 91 , wherein at least in the fully expanded configuration the shape of the intermediate opening is different from the shape of the first opening and is different from the shape of the second opening.

[0262] Embodiment 93. The stent of any one of embodiments 86 to 92, wherein the intermediate opening is a slit or punched hole.

[0263] Embodiment 94. The stent of embodiment 92, wherein the slit or punched hole is more than 50% of the circumference of the stent when the stent is in the delivery state.

[0264] Embodiment 95. The stent of embodiment 93 or 94, wherein the stent is configured to be oriented and deployed so that the slit or punched hole becomes the intermediate opening.

[0265] Embodiment 96. Th stent of embodiment 93 or 94 or 95, wherein the stent is configured to be oriented and deployed so that the slit or punched hole is aligned with the contralateral iliac ostium.

[0266] Embodiment 97. The stent of any one of embodiments 85 to 96, wherein the stent comprises one or more protruding elements forming a protruding rim at the intermediate opening.

[0267] Embodiment 98. The stent of any one of embodiments 85 to 97, wherein the protruding rim extends around a portion of or the entire perimeter of said respective intermediate opening.8787-25

[0268] Embodiment 99. The stent of embodiment 98, wherein when the stent is in its fully expanded configuration the protruding elements of the rim are configured to form a respective branch portion.

[0269] Embodiment 100. The stent of any one of the preceding embodiments 85 to 99, wherein the first or aorta portion is tubular, and the second or iliac portion is tubular.

[0270] Embodiment 101 . The stent of any one of the preceding embodiments 85 to 100, wherein the second or iliac portion is configured to pivot relative to the first or aorta portion around a pivotable connection between the first or aorta portion and the second or iliac portion, and wherein the intermediate opening is located adjacent to the pivotable connection.

[0271] Embodiment 102. The stent of any one of the preceding embodiments 85 to 101 , wherein the stent has an expandable scaffolding and is configured to transform from an unexpanded tubular state to an expanded bifurcated state.

[0272] Embodiment 103. The stent of embodiment 102, wherein the stent comprises: a first tubular section located at a first end of the stent when the stent is in the unexpanded tubular state; a second tubular section located at a second opposite end of the stent when the stent is in the unexpanded tubular state; and an intermediate section that intervenes between the first and second tubular sections.

[0273] Embodiment 104. The stent of embodiment 103, wherein the scaffolding is arranged in a first pattern in the first tubular section, the scaffolding is arranged in a second pattern in the second tubular section that is the same as the first pattern, and the scaffolding is arranged in a third pattern in the intermediate section that is different from the first and second patterns.8787-25

[0274] Embodiment 105. The stent of embodiment 103 or 104, wherein the intermediate section, in particular the third pattern of the intermediate section, includes a gap.

[0275] Embodiment 106. The stent of embodiment 104 or 105, in combination with embodiment 103, wherein the intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap.

[0276] Embodiment 107. The stent of embodiment 105 or 106, wherein the intermediate section is configured so that bending the stent at the intermediate section causes a rim around the gap to outwardly protrude from a radial side of the stent; and / or wherein in one or both the first and second stent a / the rim around the gap is configured to outwardly protrude from a radial side of the stent when the gap increases in size.

[0277] Embodiment 108. The stent of embodiment 105 or 106 or 107, wherein the intermediate section, in particular the third pattern of the intermediate section, includes a further gap, wherein the gap and further gap are positioned on opposite sides of the stent or of a central longitudinal axis of the stent.

[0278] Embodiment 109. The stent assembly of embodiment 108, wherein the intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap and decreases the size of the further gap.

[0279] Embodiment 110. The stent of any one of embodiments 103 to 109 wherein the expandable scaffolding is configured so that, when the stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the first tubular section transforms into the first or aorta portion with a first maximum radial size, in particular a first diameter, and the second tubular section transforms into the second iliac portion with a second maximum radial size, in8787-25 particular a second diameter, that is less than the first maximum radial size, in particular less than the first diameter.

[0280] Embodiment 111. The stent of any one of embodiments 103 to 110, wherein the expandable scaffolding is configured so that, when the stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the rim around the gap transforms into a branch portion that is shorter than the second or iliac portion and has the same maximum radial size, in particular the same diameter, as the second or iliac portion of the same stent.

[0281] Embodiment 112. The stent of any one of embodiments 104 to 111 , wherein the first and second patterns comprise a plurality of linear patterns.

[0282] Embodiment 113. The stent of any one of embodiments 104 to 112, wherein the third pattern comprises a radial pattern.

[0283] Embodiment 114. The stent of embodiment 113, wherein the third pattern further comprises a plurality of linear patterns.

[0284] Embodiment 115. The stent of any one of embodiments 104 to 114, further comprising markers in the scaffolding that are positioned to indicate the location of at least one of a first end of the stent at the first tubular section, a second end of the stent in the second tubular section, of the gap and optionally of the further gap.

[0285] Embodiment 116. The stent of embodiment 115, wherein at least some of the markers are positioned adjacent to the gap and, optionally, adjacent to the further gap.

[0286] Embodiment 117. The stent of any one of embodiments 102 to 116, wherein the stent is configured to transform from a linear tubular structure to an asymmetric bifurcated structure by bending the linear tubular structure at the intermediate section, the asymmetric bifurcated structure having a main trunk and two branches, the branches having different lengths and the main trunk having a greater diameter than the two branches.8787-25

[0287] Embodiment 118. The stent of any one of embodiments 103 to 117, wherein: the scaffolding in the first tubular section comprises a plurality of linear patterns configured to form a plurality of rings; the scaffolding in the second tubular section comprises a plurality of linear patterns configured to form a plurality of rings; and the scaffolding in the intermediate section comprises a radial pattern.

[0288] Embodiment 119. The stent of any one of embodiments 103 to 118, in combination with embodiment 105, wherein the gap is centrally positioned at the intermediate section.

[0289] Embodiment 120. The stent of any one of embodiments 118 to 119, wherein the scaffolding in the intermediate section further comprises a plurality of linear patterns that are separated from the first and second tubular sections.

[0290] Embodiment 121 . The stent of any one of embodiments 85 to 120, wherein the stent is a partially covered stent or a totally covered stent.

[0291] Embodiment 122. The stent of any one of embodiments 85 to 121 , wherein the stent comprises a scaffolding and a covering, optionally a membrane covering.

[0292] Embodiment 123. The stent of embodiment 122, wherein the scaffolding is partially or completely enclosed by the covering.

[0293] Embodiment 124. The stent of embodiment 122 or 123, wherein the stent is completely covered by the covering, optionally wherein the covering is a bio-compatible covering.

[0294] Embodiment 125. The stent of any one of the preceding three embodiments, wherein the covering is a membrane covering, optionally a wherein the membrane covering is made of plastic, more optionally made from EPTFE or TPU.

[0295] Embodiment 126. The stent of any one of the preceding four embodiments, wherein the covering has an opening at the intermediate opening.8787-25

[0296] Embodiment 127. The stent of any one of embodiments 85 to 126 configured to receive the first or arterial portion of an identical stent through the intermediate opening and form the assembly of any one of embodiments 1 to 84.REFERENCES TO THE DRAWINGS10 Aorta-iliac bifurcation Region12 Aorta14 Carina16 Oval transverse section18 Ipsilateral iliac artery20 Contralateral iliac artery22 First kissing stent24 Second kissing stent26 Gap28 First iliac stent29 Second iliac stent30 Aortic cap stent32 Gap33 Gap34 Stent assembly35 First asymmetric stent36 Second asymmetric stent38 Aorta portion39 Iliac portion40 Intermediate region41 First openingSecond openingThird openingAorta portionIliac portionIntermediate regionFirst openingSecond openingThird openingAorta portion ringIntra sectional bridgeAorta portion strutsIliac portion strutsIntra sectional bridgeIliac portion struts axially extending strut LipRadially repeating patternCentral linearly repeating patternFirst outer linearly repeating pattern Second outer linearly repeating pattern Third outer linearly repeating pattern Inter sectional bridgeInter sectional bridgeInter sectional bridgeInter sectional bridgeInter sectional bridgeRadiopaque markerSheathCatheterMarkerGuidewire portFirst guidewireMarkerSecond guidewireSecond catheterGuidewire portSheathThird guidewireCatheter coreFirst sheathSecond sheathGuidewireGuidewireGuidewireSplit sleeveDistal sleeveCatheterProximal sleeveSecond guidewireHandleBuddy wireKnob8787-25 First Wire Second Wire First Spindle Second Spindle

Claims

1. 8787-25CLAIMS1 . A stent assembly configured to maintain a lumen in a bifurcated vessel, the stent assembly comprising: a first stent with an intermediate opening on a side of the first stent; and a second stent with an intermediate opening on a side of the second stent, wherein a portion of the second stent with the second stent intermediate opening is configured to be nested within the first stent.

2. The stent assembly of claim 1 , wherein the first stent has a first opening at a first end, a second opening at a second end, and wherein the first stent intermediate opening is on the side of the first stent between the first and second openings of the same first stent; and wherein the second stent has a first opening at a first end, a second opening at a second end, and wherein the second stent intermediate opening is on the side of the second stent between the first and second openings of the same second stent.

3. The stent assembly of claim 1 or 2, said portion of the second stent provided with the second stent intermediate opening is configured to be nested within the first stent at least when the first stent is in its fully expanded configuration.

4. The stent assembly of any one of the preceding claims, wherein at least when the first stent is in its fully expanded configuration, the second stent is configured to extend through the intermediate opening of the first stent and the intermediate opening in the first stent is configured to receive the second stent.8787-255. The stent assembly of claims 2 and 4, wherein when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent, the intermediate opening in the second stent is configured to align with the first opening in the first stent and allow fluid to flow through from the first opening to the second opening of the first stent.

6. The stent assembly of any one of the preceding claims, wherein the first and second stents are identical.

7. The stent assembly of any one of the preceding claims, wherein the stent assembly is configured to maintain a lumen in an aorta-iliac bifurcation region at least when the first and second stents are in their fully expanded configuration; and wherein each of the first and second stents comprises an aorta portion configured to be positioned within an aorta and an iliac portion configured to be positioned within an iliac artery.

8. The stent assembly of claim 7, wherein, for each of the first and second stents in their fully expanded configuration, a maximum radial size, in particular a diameter, of the aorta portion is larger than a maximum radial size, in particular a diameter, of the iliac portion.

9. The stent assembly of any one of claims 7 to 8, wherein the intermediate opening in the first stent is configured to be aligned with the iliac portion of the second stent; wherein the intermediate opening in the second stent is configured to be aligned with the iliac portion of the first stent.8787-2510. The stent assembly of any one of the preceding claims, wherein the first stent is asymmetric at least when in its fully expanded configuration; and wherein the second stent is asymmetric at least when in its fully expanded configuration.11 . The stent assembly of any one of the preceding claims, wherein the first and second stents are configured such that: when the first and second stents are coupled together with the second stent intermediate opening nested within the first stent, and when the first and second stents are in their fully expanded configuration in a vessel lumen region that changes transverse dimensions and shape, optionally in a bifurcation region, said first and second stents conform to and scaffold inner walls of said vessel lumen region.

12. The stent assembly of any one of the preceding claims, wherein each of the first and second stents comprises a scaffolding and a covering, optionally a membrane covering, wherein the scaffolding is partially or completely enclosed by the covering, more optionally wherein the covering is a bio-compatible covering.

13. The stent assembly of the preceding claim, wherein the covering is a membrane covering, optionally a wherein the membrane covering is made of plastic, more optionally made from EPTFE or TPU; and / or wherein in each of the first and second stents the covering has an opening at the intermediate opening.8787-2514. The stent assembly of any one of the preceding claims, in combination with claim 12 or 13, wherein the first and second stents are configured such that: when the first and second stents are coupled together with the second stent portion nested within the first stent and when the first and second stents are in their fully expanded configuration in a vessel lumen region, optionally in a bifurcation region, the first and second stents present overlapping stent coverings, in particular wherein the overlapping stent coverings are configured for providing a seal against leaks outside of the stent assembly through the scaffolding.

15. The stent assembly of any one of the preceding claims, wherein the first and second stent intermediate openings are configured to be positioned to face opposite lateral directions when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent; and / or wherein the first and second stents are configured to be positioned in orientations that laterally mirror each other when the first and second stents are in their fully expanded configuration and said portion of the second stent is nested within the first stent.

16. The stent assembly of any one of the preceding claims, wherein the first stent is expandable from a collapsed configuration to a / the fully expanded configuration, and wherein the second stent is expandable from a collapsed configuration to a / the fully expanded configuration; further wherein the first and second stents are self-expanding or expanded by deploying and inflating corresponding balloons.8787-2517. The stent assembly of claim 16, when combined with claim 7, wherein a maximum radial size, in particular a diameter, of a cross section of the aorta portion of the first stent is greater when the first stent is in its fully expanded configuration than when the first stent is in the collapsed configuration; and wherein a maximum radial size, in particular a diameter, of a cross section the aorta portion of the second stent is greater when the second stent is in its fully expanded configuration than when the second stent is in the collapsed configuration.

18. The stent assembly of claim 16 or 17, when combined with claim 7, wherein a maximum radial size of a cross section of the iliac portion of the first stent is greater when the first stent is in its fully expanded configuration than when the first stent is in the collapsed configuration; and wherein a maximum radial size of a cross section the iliac portion of the second stent is greater when the second stent is in its fully expanded configuration than when the second stent is in the collapsed configuration.

19. The stent assembly of any one of the preceding claims, when combined with claim 16, wherein the first stent is configurable in: a delivery state, in which the first stent takes the collapsed configuration, optionally a collapsed linear and coaxial configuration, and a fully deployed state, in which the first stent takes the fully expanded configuration; and / or wherein the second stent is configurable in: a delivery state, in which the second stent takes the collapsed configuration, optionally a collapsed linear and coaxial configuration, and8787-25 a fully deployed state, in which the second stent takes the fully expanded configuration; wherein with the first stent in the deployed state, the second stent can be inserted, deployed and, optionally, expanded, through the first stent side opening.

20. The stent assembly of claim 19, wherein for each of the first and second stents, the intermediate opening is a slit or punched hole that is more than 50% of the circumference of the stent when the stent is in the delivery state; and wherein the first stent is configured to be oriented and deployed so that the slit or punched hole becomes the intermediate opening and is aligned with the contralateral iliac ostium.21 . The stent assembly of any one of the preceding claims, in combination with claim 7, wherein each of the first and second stents has the aorta portion which is configured to be shape set to a larger maximum radial size, in particular a larger diameter, than the iliac portion.

22. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein each of the first and second stents has an intermediate portion connecting the aorta portion to the iliac portion; wherein the cross-sectional area of each of the first and second stents is greater in the aorta portion than in the iliac portion; and wherein the cross-sectional area of the intermediate portion of each of the first and second stents increases from the aorta portion toward the iliac portion.

23. The stent assembly of any one of the preceding claims, in combination with claims 2, 7 and 22, wherein each of the first and second stents has the first opening at the end of the aorta portion, the second opening at the end of the iliac8787-25 portion, and the intermediate opening located at the intermediate portion between the first and second openings.

24. The stent assembly of any one of the preceding claims, in combination with claims 7 and 22, wherein the aorta portion and the intermediate portion of the second stent are configured to be positioned entirely within the aorta portion and intermediate portion of the first stent so that the second stent is partially nested within the first stent.

25. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein with the second stent inserted through the first stent intermediate opening and expanded inside the first stent, the aorta portions of the two stents are nested and overlap and the iliac portions of the two stents diverge forming an inverted Y-shape scaffolding approximating the aortic bifurcation.

26. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to extend beyond the aorta portion of the second stent.

27. The stent assembly of any one of the preceding claims, in combination with claim 8, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the first stent intermediate opening is configured to be aligned with the iliac portion of the second stent and the second stent intermediate opening is configured to be aligned with the iliac portion of the first stent.8787-2528. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to completely surround and embrace the aorta portion of the second stent.

29. The stent assembly of any one of the preceding claims, in combination with claim 9, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, the aorta portion of the first stent is configured to be coaxial with the aorta portion of the second stent.

30. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, a radially external surface of the aorta portion of the second stent is configured to overlap with and contact a radially internal surface of the aorta portion of the first stent along an entire circumferential development of the aorta portion of the second stent.31 . The stent assembly of any one of the preceding claims, in combination with claim 7, wherein when the first and second stents are in their fully expanded configuration and said aorta portion of the second stent is nested within the first stent, a radially external surface of the aorta portion of the second stent is configured to overlap and come into contact with a radially internal surface of the aorta portion of the first stent forming a mutual contact surface which develops around the aorta portion of the second stent and extends axially until the opening of the aorta portion of the same second stent.8787-2532. The stent assembly of any one of the preceding claims, in combination with claims 2, 7, and 22, wherein the first stent has: the aorta portion with a first diameter, the first opening being an inlet opening located at an end of the aorta portion and configured to receive blood flowing into the first stent; the iliac portion with a second diameter that is smaller than the first diameter, the second opening being a first outlet opening being located at an end of the iliac portion and configured to discharge part of the blood flowing through the first stent; and the intermediate portion connecting the aorta portion to the iliac portion, with the intermediate opening being a second outlet opening positioned in the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the first stent; and wherein the second stent has: the aorta portion with a first diameter, the first opening being an inlet opening located at an end of the aorta portion and configured to receive blood flowing into the second stent; the iliac portion with a second diameter that is smaller than the first diameter, the second opening being a first outlet opening located at an end of the iliac portion and configured to discharge part of the blood flowing through the second stent; and the intermediate portion connecting the aorta portion to the iliac portion, with the intermediate opening being a second outlet opening positioned in the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the second stent; in particular wherein in each of the first and second stents the aorta portion is tubular, and the iliac portion is tubular.8787-2533. The stent assembly of claim 32, wherein in each of the first and second stents the inlet opening and the second outlet opening are larger than the first outlet opening, a cross-sectional area of the intermediate portion is varied and cross sectional areas of the aorta portion and of the iliac portion are constant.

34. The stent assembly of any one of the preceding claims 32 to 33, wherein in each of the first and second stents the shape of the second outlet opening is different from the shape of the first outlet opening and is different from the shape of the inlet opening.

35. The stent assembly of any one of the preceding claims in combination with claim 7, wherein each of the first and second stents comprises one or more protruding elements forming a protruding rim at the respective first or second stent intermediate opening, the protruding rim extending around a portion of or the entire perimeter of said respective intermediate opening.

36. The stent assembly of claim 35, wherein when the first and second stents are in their fully expanded configuration:- the protruding elements of the rim the first stent are configured to form a respective branch portion with a radially inner surface that surrounds and comes into contact with a mating radially external surface of the iliac portion of the second stent; and- the protruding elements of the rim of the second stent are configured to form a respective branch portion with a radially outer surface that is inserted and comes into contact with a mating radially inner surface of the iliac portion of the second stent.8787-2537. The stent assembly of any one of the preceding claims, in combination with claim 7, wherein in each of the first and second stents the iliac portion is configured to pivot relative to the aorta portion around a pivotable connection between the aorta portion and the iliac portion, and wherein the intermediate opening is located adjacent to the pivotable connection.

38. The stent assembly of any one of the preceding claims, wherein each of the first and second stents comprises a plurality of markers, optionally wherein the markers are radiopaque markers, configured to indicate a position of the stent relative to the vessels in which the stent is inserted.

39. The stent assembly of claims 38, in combination with claim 35, wherein the plurality of markers includes markers that are positioned adjacent to or at the rim, optionally in correspondence of the one or more protruding elements of the rim, of the respective first or second stent; and / or wherein in each of the first and second stents the plurality of markers includes markers that are positioned at a proximal end of the iliac portion and at a distal end of the aorta portion.

40. The stent assembly of any one of the preceding claims, wherein both the first stent and second stent have an expandable scaffolding and are configured to transform from an unexpanded tubular state to an expanded bifurcated state.41 . The stent assembly of claim 40, wherein both the first and second stent comprise: a first tubular section located at a first end of the stent when the stent is in the unexpanded tubular state;8787-25- a second tubular section located at a second opposite end of the stent when the stent is in the unexpanded tubular state; and- an intermediate section that intervenes between the first and second tubular sections; wherein both the first and second stent the scaffolding is arranged in a first pattern in the first tubular section, the scaffolding is arranged in a second pattern in the second tubular section that is the same as the first pattern, and the scaffolding is arranged in a third pattern in the intermediate section that is different from the first and second patterns.

42. The stent assembly of claim 41 , wherein in both the first and second stent the intermediate section, in particular the third pattern of the intermediate section, includes a gap; and wherein the first and second stent intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap.

43. The stent assembly of claim 41 or 42, wherein in both the first and second stent the intermediate section is configured so that bending the stent at the intermediate section causes a rim around the gap to outwardly protrude from a radial side of the stent; and / or wherein in both the first and second stent the rim around the gap is configured to outwardly protrude from a radial side of the stent when the gap increases in size.

44. The stent assembly of claim 42 or 43, wherein in both the first and second stent the intermediate section, in particular the third pattern of the intermediate section, includes a further gap, wherein the gap and further gap are positioned on opposite sides of the respective stent or of a central longitudinal axis of the respective stent;8787-25 optionally wherein in both the first and second stent the intermediate section is configured so that bending the stent at the intermediate section increases the size of the gap and decreases the size of the further gap.

45. The stent assembly of any one of claims 41 to 44, when combined with claim 7 wherein, in one or both the first and second stent, the expandable scaffolding is configured so that, when the respective stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the first tubular section transforms into the aorta portion with a first maximum radial size, in particular a first diameter, and the second tubular section transforms into the iliac portion with a second maximum radial size, in particular a second diameter, that is less than the first maximum radial size, in particular less than the first diameter.

46. The stent assembly of any one of claims 41 to 45, when combined with claims 7 and 43 wherein, in one or both the first and second stent, the expandable scaffolding is configured so that, when the respective stent from the unexpanded tubular state is expanded and / or bent at the intermediate section, the rim around the gap transforms into a branch portion that is shorter than the iliac portion and has the same maximum radial size, in particular the same diameter, as the iliac portion of the same stent.

47. The stent assembly of any one of claims 41 to 46, wherein the first and second patterns comprise a plurality of linear patterns; wherein the third pattern comprises a radial pattern, optionally wherein the third pattern further comprises a plurality of linear patterns.

48. The stent assembly of any one of claims 40 to 47, wherein the stent is configured to transform from a linear tubular structure to an asymmetric8787-25 bifurcated structure by bending the linear tubular structure at the intermediate section, the asymmetric bifurcated structure having a main trunk and two branches, the branches having different lengths and the main trunk having a greater diameter than the two branches.

49. The stent assembly of any one of claims 41 to 48, wherein: the scaffolding in the first tubular section comprises a plurality of linear patterns configured to form a plurality of rings; the scaffolding in the second tubular section comprises a plurality of linear patterns configured to form a plurality of rings; and the scaffolding in the intermediate section comprises a radial pattern; wherein a / the gap is centrally positioned at the intermediate section; optionally wherein the scaffolding in the intermediate section further comprises a plurality of linear patterns that are separated from the first and second tubular sections.

50. A stent configured to be used as first or second stent in the stent assembly of any one of the preceding claims, where in the stent comprises: a first or aorta portion having a first opening configured to receive blood flowing into the stent; a second or iliac portion having a second opening configured to discharge part of the blood flowing through the stent; and an intermediate portion, connecting the first or aorta portion to the second or iliac portion, having an intermediate opening positioned on a side of the intermediate portion and configured to discharge out of the intermediate portion part of the blood flowing through the stent; wherein the stent is expandable, optionally self-expandable, wherein the stent is asymmetric at least in the fully expanded configuration.8787-2551 . The stent of the preceding claim configured to receive the first or arterial portion of an identical stent through the intermediate opening and form the assembly of any one of claims 1 to 49.

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