Stent graft for aneurysm with minimal landing zone

Abstract

An implantable medical device for bypassing an aneurysm, comprising a first stent having a first diameter; a second stent positioned at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and a graft coupled to the first stent and to the second stent, the graft defining a lumen through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.

Description

STENT GRAFT FOR ANEURYSM WITH MINIMAL LANDING ZONECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional Application No. 63 / 718,211 , filed November 8, 2024, which is incorporated herein by reference in its entirety for all purposes.FIELD

[0002] The present disclosure relates generally to apparatuses, systems, and methods for vascular treatment. More specifically, the disclosure relates to apparatuses, systems, and methods for treating aneurysms in the vasculature with minimal landing zones, such as stent grafts that can be deployed to treat aneurysms with minimal landing zones.BACKGROUND

[0003] Aortic aneurysm frequently lack the requisite landing zone (e.g., 1-2 cm) needed to perform an endoluminal intervention with a stent graft. A “landing zone” is generally the requisite area needed to properly anchor to adjacent vascular tissue and / or seal off an aneurysm during graft, or stent graft deployment. For example, aneurysms in the ascending aorta typically involve vascular tissue up to, and frequently past, the sinotubular junction on the proximal end of the ascending aorta. The standard treatment for individuals who have pathologies in the aorta with no landing zone, or an insufficient landing zone, is to perform open sternotomy surgery on the ascending aorta (e.g., as opposed to a much less invasive endoluminal procedure using catheterization of the vasculature to deploy a stent graft).

[0004] Generally, existing solutions require sternotomy, cardiac arrest, and cardiopulmonary bypass - and may further require hypothermic circulatory arrest (e.g., if arch vessels require treatment). Hospital stays for these procedures are typically around a week, including about 1-2 days in the cardiovascular intensive care unit, and then up to 3-6 months before patients return to a normal baseline. Complications from surgical interventions include increased risk of infection, risk of stroke (with potentially a day or more before detection), significant pain limiting activities of daily life, hemodynamic instability (e.g., coagulopathy), personality changes due to attendant complications, and others. These procedures also carry the risk of addiction to pain1DMS_US.367207894.1medications during the relatively longer recovery process.

[0005] Unique properties of the ascending aorta make treatment via endovascular means particularly challenging. Mechanical attributes of the ascending aorta include the following: the ascending aorta is pulsatile and experiences torque, bending, and longitudinal compression and extension under physiologic conditions. Mismatch of these properties with an implanted device can increase, for example, heart strain. And, the relatively short length of the ascending aorta (particularly the inner curve) can make it more difficult to anchor to and / or obtain an adequate seal with the aorta using a standard endograft.SUMMARY

[0006] An implantable medical device for implantation at aneurysmal sites with limited landing zones is provided herein.

[0007] According to one example (“Example 1”), an implantable medical device for bypassing an aneurysm includes a first stent having a first diameter; a second stent positioned at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and a graft coupled to the first stent and to the second stent, the graft defining a lumen through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.

[0008] According to another example (“Example 2”) further to Example 1 , the first stent includes a first transverse deformation resistance and the second stent includes a second transverse deformation resistance that is different than the first transverse deformation resistance.

[0009] According to another example (“Example 3”) further to Example 2, the second transverse deformation resistance is greater than the first transverse deformation resistance.

[0010] According to another example (“Example 4”) further to Example 1 , the first stent is configured to conform to a profile of the aneurysm.

[0011] According to another example (“Example 5”) further to Example 4, the first stent is configured to exert a radial force sufficient to contact the aneurysm without exerting a significant force on the aneurysm.2DMS_US.367207894.1

[0012] According to another example (“Example 6”) further to Example 1 , the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

[0013] According to another example (“Example 7”) further to Example 6, the intermediate space between the first and second stents when in the deployed configuration has a greater thickness than a thickness of the graft.

[0014] According to another example (“Example 8”) further to Example 1 , the implantable medical device includes at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

[0015] According to another example (“Example 9”) further to Example 1 , the first stent has a first longitudinal length and the second stent has a second longitudinal length, wherein the first longitudinal length is different from the second longitudinal length.

[0016] According to another example (“Example 10”) further to Example 1 , the first stent and the second stent are a combination of balloon-expandable and selfexpandable.

[0017] According to an example (“Example 11 ) an implantable medical device for bypassing an aneurysm, includes a first stent having a first transverse deformation resistance, the first stent configured to conform a profile of the aneurysm; a second stent positioned at least partially within the first stent, the second stent having a second transverse deformation resistance, the second transverse deformation resistance being greater than the first transverse deformation resistance; and a graft coupled to the first stent and to the second stent.

[0018] According to another example (“Example 12”) further to Example 11 , the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

[0019] According to another example (“Example 13”) further to Example 12, the first and second stents are configured to define a variable thickness intermediate space between the first and second stents when the first and second stents are in a deployed configuration and the first stent is engaged with an aneurysmal portion of a vessel.3DMS_US.367207894.1

[0020] According to another example (“Example 14”) further to Example 11 , the implantable medical device further includes at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

[0021] According to another example (“Example 15”) further to Example 11 , the first stent includes a helical stent.

[0022] According to another example (“Example 16”) further to Example 11 , the first stent includes a ring stent.

[0023] According to another example (“Example 17”), an implantable medical device for bypassing an aneurysm, includes a first stent having a first diameter, a first end, and a second end; a second stent positioned at least partially within the first stent, the second stent having a second diameter, a first end, and a second end, the second diameter being smaller than the first diameter; and a graft coupled to the first stent and to the second stent, the graft extending from the first end of the first stent to the second end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

[0024] According to another example (“Example 18”) further to Example 17, the first stent includes a first transverse deformation resistance and the second stent includes a second transverse deformation resistance that is different than the first transverse deformation resistance.

[0025] According to another example (“Example 19”) further to Example 18, the second transverse deformation resistance is greater than the first transverse deformation resistance.

[0026] According to another example (“Example 20”) further to Example 17, the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

[0027] According to another example (“Example 21”) further to Example 17, an intermediate space between the first and second stents when in a deployed configuration has a greater thickness than a thickness of the graft.

[0028] According to another example (“Example 21”) further to Example 17, the implantable medical device includes at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

[0029] According to another example (“Example 22”) further to Example 17, the4DMS_US.367207894.1graft extends between the first end of the first stent and the first end of the second stent, along the second stent, and between the second end of the second stent and the second end of the first stent.

[0030] According to one example (“Example 24”), an implantable medical device includes an outer layer including a graft material reinforced with a self-expanding material and having first and second longitudinal ends; and an inner layer including a graft material coupled to the outer layer at the first and second longitudinal ends of the outer layer, wherein a central portion of the inner layer is operable to expand and contract free of the outer layer.

[0031] According to one example (“Example 25”), a method of treating an aneurysm with an implantable medical device having multiple layers includes delivering an endoprosthesis to a treatment zone; expanding an outer layer first end portion to anchor an endoprosthesis on one side of treatment zone; expanding an outer layer second end portion on an opposite side of treatment zone; and expanding an inner layer of the implantable medical device to allow fluid flow along length of the implantable medical device.

[0032] According to one example (“Example 26”), a method of manufacturing an implantable medical device, includes providing a first stent having a first diameter; positioning a second stent at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and coupling a graft to at least one of the first stent and to the second stent, the graft defining a lumen through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.

[0033] The foregoing Examples are just that, and should not be read to limit or otherwise narrow the scope of any of the inventive concepts otherwise provided by the instant disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature rather than restrictive in nature.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are included to provide a further5DMS_US.367207894.1understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description serve to explain the principles of the disclosure.

[0035] FIG. 1 is an illustration of an aorta with an aneurysm in the ascending segment;

[0036] FIG. 2 is an illustration of an implantable device in the ascending segment of the aorta, in accordance with an embodiment;

[0037] FIGS. 3A-6 are illustrations of a cross-section of various embodiments of an implantable device;

[0038] FIGS. 7 and 8 illustrate various embodiments of an implantable device in which one of the first stent and second stent are longitudinally longer than the other;

[0039] FIG. 9 illustrates an embodiment of an implantable device in which the graft material does not extend along the full length of the first stent; and

[0040] FIGS. 10-12 illustrate various embodiments of an implantable medical device.DETAILED DESCRIPTIONDefinitions and Terminology

[0041] This disclosure is not meant to be read in a restrictive manner. For example, the terminology used in the application should be read broadly in the context of the meaning those in the field would attribute such terminology.

[0042] With respect to terminology of inexactitude, the terms “about” and “approximately” may be used, interchangeably, to refer to a measurement that includes the stated measurement and that also includes any measurements that are reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant arts. Such deviations may be attributable to measurement error, differences in measurement and / or manufacturing equipment calibration, human error in reading and / or setting measurements, minor adjustments made to optimize performance and / or structural parameters in view of differences in measurements associated with other components, particular implementation scenarios, imprecise adjustment and / or manipulation of objects by a person or machine, and / or the like, for example. In the event it is determined that individuals having ordinary skill in the relevant arts would not6DMS_US.367207894.1readily ascertain values for such reasonably small differences, the terms “about” and “approximately” can be understood to mean plus or minus 10% of the stated value.

[0043] As used herein the term “landing zone” is defined as the requisite area needed to properly anchor to adjacent vascular tissue and / or seal off an aneurysm during stent graft deployment.

[0044] As used herein the term “transverse deformation resistance” is defined as resistance to deformation in a substantially transverse plane to a longitudinal axis of a support structure. Examples of measures of transverse compressive resistance include radial compressive resistance, hoop strength, and flat plate stiffness, for example.Description of Various Embodiments

[0045] Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatuses configured to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not necessarily drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawing figures should not be construed as limiting.

[0046] The device shown in FIG. 2 is provided as an example of the various features of the device and, although the combination of those illustrated features is clearly within the scope of invention, that example and its illustration is not meant to suggest the inventive concepts provided herein are limited from fewer features, additional features, or alternative features to one or more of those features shown in FIGS. 3-6

[0047] Referring to FIG. 1 , an example of an aorta 10 of a patient is illustrated. As shown in FIG. 1 , the aorta 10 includes an ascending aorta 12 that includes an aneurysm. The ascending aorta 12 is curved leading into the aortic arch 14. The ascending aorta defines an inside curve 16 and an outside curve 18, where the outside curve 18 is longer than the inside curve. For example, the outside curve 18 may be about 30% to about 200% longer than the inside curve 16. In some situations, the inside curve 16 may be only about 3 cm in length and therefore is difficult to achieve a proximal seal and fixation to treat an aneurysm.

[0048] FIG. 2 illustrates an implantable medical device 100 for bypassing the aneurysm in the ascending aorta 12. The implantable medical device 100 is positioned within the ascending aorta to form a seal with and fixation to the ascending aorta 12. In7DMS_US.367207894.1some embodiments, the seal is formed at an end or both ends of the implantable medical device 100. In some embodiments, the seal is formed along an entire length of implantable medical device 100. The implantable medical device 100 defines a lumen 102 through which blood may flow to bypass a targeted region of the aorta. The implantable medical device 100 may simulate mechanical properties unique to the ascending aorta 12 including responsiveness to pulsatile forces and torque, and the ability to bend, longitudinally compress, and longitudinally extend. In some embodiments, the implantable medical device 100 includes a first stent 104, a second stent 106, and a graft 108.

[0049] As shown in FIGS. 2-6, the first and second stents 104, 106 are provided in such a way that the second stent 106 is positioned at least partially within the first stent 104. That is, the first stent 104 and the second stent 106 each define a respective lumen 105, 107. The second stent 106 is positioned at least partially within the lumen105 of the first stent 104. The second stent 106 may be positioned such that the first and the second stents 104, 106 are substantially concentric. However, non-concentric arrangements are also contemplated. The first stent 104 typically has a first diameter and the second stent 106 a second diameter, where the first and second diameters are different from each other. In some embodiments, the first diameter is greater than the second diameter such that when the second stent 106 is positioned within the first stent 104, an intermediate space 110 is defined between the first stent 104 and the second stent 106. The first stent 104 is configured to exert a radial force sufficient contact the aneurysm without exerting a significant force on the aneurysm.

[0050] In various examples, the implantable medical device 100 is adapted to take on different configurations (e.g., a delivery configuration and a deployed configuration). In some embodiments, the intermediate space 110 is variable in size in the different configurations of the implantable medical device 100. For example, in the delivery configuration, the intermediate space 110 may be substantially negligible, or relatively smaller than in the deployed configuration, as the first and second stents 104,106 are constrained to a smaller diameter in the delivery configuration such that the first stent 104 may be closely received in (e.g., coaxially positioned against or engaged with) the second stent 106. However, when the implantable medical device 100 is in a deployed configuration (e.g., an unconstrained configuration in which the implantable medical device has been allowed to self-expand to a larger diameter), the intermediate space 110 defined between the first and second stents 104, 106 is relatively larger, as8DMS_US.367207894.1the first stent 104 and the second stent 106 are positioned at a greater spacing from each other. This variable spacing between delivery and deployed configurations facilitates a relatively low profile in the delivery configuration, and also the ability of the second stent 106 to expand in the deployed configuration to provide a flow path while also allowing the first stent 104 expand to in the deployed configuration to contact and anchor I seal with the vessel wall of the ascending aorta 12.

[0051] In some embodiments, the first and second stents 104, 106 may be coupled to each other via the graft 108. For example, the graft 108 may be coupled to the first stent 104 and to the second stent 106 such that the graft 108 defines or bounds the lumen 102 as defined by the second stent 106 (e.g., lumen 107 of the second stent 106), such that the lumen 102 bounded by the graft 108 is configured to direct blood flow through the second stent 106. The graft 108 is generally configured to limit (e.g., reduce or prevent) blood flow between the first stent 104 and the second stent 106 (e.g., limiting blood flow into the intermediate space 110).

[0052] In some embodiments, the first and second stents 104, 106 may be substantially mechanically isolated from each other when in the deployed configuration. This may be accomplished by coupling the first and second stents 104, 106 to each other via the graft 108. The graft 108 may be coupled to the first and second stents 104, 106 such that a length of the graft 108 extending between the first and the second stents 104, 106 is about equal to the difference between the diameter of the first stent 104 and the diameter of the second stent 106. In various examples, the two stents may not be completely mechanically isolated from each other, and some forces may still be transmitted from the first stent 104 to the second stent 106 or from the second stent 106 to the first stent 104 via the graft 108. However, such mechanical forces transmitted between the first and second stents 104, 106.

[0053] In some embodiments, the first stent 104 includes a first transverse deformation resistance and the second stent 106 includes a second transverse deformation resistance that is different than the first transverse deformation resistance. For example, the first stent 104 may have a first transverse deformation resistance that is less that the second transverse deformation resistance. This helps facilitate conformance of the first stent to the inner surface, or inner profile of the ascending aorta 12 without exerting high forces on the aneurysm which could result in disease progression and potentially rupture. In various examples, a length of the first stent 104 or circumferential surface area of the first stent 104 engaging with the inner surface of9DMS_US.367207894.1the aorta defines a landing zone of the implantable medical device 100 with the aorta. The greater conformability of the first stent 104 may help facilitate a greater length or area landing zone by allowing close conformation to the tissue of the aorta, including along at least a portion of the aneurysmal portion of the aorta. In some examples, the second transverse deformation resistance is tuned to mimic at least some of the properties of a typical ascending aorta 12. For example, the second transverse deformation resistance of the second stent 106 may be similar to that of the ascending aorta. For reference, the ascending aorta is able to elastically expand after systole and pushes blood during diastole. Thus, the second stent 106 may be provided with similar properties (sufficient conformability and the ability to exhibit elastic dilation and contraction) to provide the Windkessel effect.

[0054] As previously referenced, the graft 108 is provided to facilitated exclusion of blood flow from the aneurysm. In some embodiments, the first stent 104 includes a first end 120 and a second end 122, the second stent 106 includes a first end 124 and a second end 126, and the graft 108 extends from the first end 120 of the first stent 104 to the first end 124 of the second stent 106, along the second stent 106 (e.g., between the first and second ends 124, 126), and from the second end 126 of the second stent 106 to the second end 122 of the first stent 104. In some embodiments, the graft 108 may also extend along the first stent 104 (e.g., between the first and second ends 120, 122). The intermediate space 110 may be partially or completely enclosed by the graft 108. In some embodiments, the intermediate space between the first and second stents 104, 106 has a thickness in the deployed configuration that is greater than a thickness of the graft 108. In some embodiments, the graft 108 may be positioned with the second stent 106 and partially everted to be positioned with the first stent 104 such that the graft 108 extends between the first ends 120, 124 of the first and second stents 104, 106 and the second ends 122, 126 of the first and second stents 104, 106. As shown, the first and second stents 104, 106 have similar lengths and are coextensive at the ends. However, in other embodiments, the first and second stents 104, 106 may have different lengths. For example, the second stent 106 may be shorter than the first stent 104, or vice versa, with one stent projecting beyond the end(s) of the other stent.

[0055] Turning to FIGS. 3-6, the graft 108 may be arranged with the first and second stents 104, 106 in various arrangements. Referring first to FIG. 3, the first stent 104 includes an interior surface 130 and an exterior surface 132 extending between the first and second ends 120, 122. The second stent 106 also includes an interior surface10DMS_US.367207894.1134 and an exterior surface 136 extending between the first and second ends 124, 126. The graft 108 is coupled to the first and second stents 104, 106 such that the graft 108 is positioned exterior to the first stent 104 (e.g., coupled to at least a portion of the exterior surface 132 of the first stent 104) and interior to the second stent 106 (e.g., coupled to at least a portion of the interior surface 134 of the second stent 106). Referring to FIG. 4, the graft 108 is coupled to the first and second stents 104, 106 such that the graft 108 is positioned interior to the first stent 104 (e.g., coupled to at least a portion of the interior surface 130 of the first stent 104) and interior to the second stent 106 (e.g., coupled to at least a portion of the interior surface 134 of the second stent 106). Referring to FIG. 5, the graft 108 is coupled to the first and second stents 104, 106 such that the graft 108 is positioned exterior to the first stent 104 (e.g., coupled to at least a portion of the exterior surface 132 of the first stent 104) and exterior to the second stent 106 (e.g., coupled to at least a portion of the exterior surface 136 of the second stent 106). Referring to FIG. 6, the graft 108 is coupled to the first and second stents 104, 106 such that the graft 108 is positioned interior to the first stent 104 (e.g., coupled to at least a portion of the interior surface 130 of the first stent 104) and exterior to the second stent 106 (e.g., coupled to at least a portion of the exterior surface 136 of the second stent 106).

[0056] It is understood that the graft 108 may be provided in various arrangements as described above. Furthermore, the graft may be provided in various forms. For example, the graft 108 may be an extruded tube, tape wrapped, or otherwise. For example, in some embodiments, the graft 108 may be an extruded tube that is positioned in the lumen 107 of the second stent 106 and exerted to couple to the first stent 104 (see FIG. 9). In other embodiments, the graft 108 may be provided as a construct similar to a tubular balloon (e.g., a cylindrical shape). The exterior surface of the graft 108 is exposed to the external environment (e.g., the patient’s vessel and blood flow) and the interior surface of the graft 108 is positioned toward the intermediate space 110 between the first and second stents 104, 106.

[0057] In some embodiments, in order to securely coupled the implantable medical device 100 to the aorta 10 without exerting high radial forces to the aneurysmal site, the implantable medical device may include at least one of an anchor 140 or a bioadhesive 142 configured to anchor the first stent 104 and / or graft 108 to the tissue.

[0058] It is understood that various stent structures may be implanted with respect to the first and second stents 104, 106. For example, in some embodiments, the11DMS_US.367207894.1first and / or second stent 104, 106 may include a helical stent. In some embodiments, the first and / or second stent 104, 106 may include a ring stent (e.g., a purely circumferential turn, and not helically arranged for one or more turns).

[0059] Referring to FIGS. 7 and 8, in some embodiments the first and second stents 104, 106 may be provided with different lengths from each other. For example, FIG. 7 illustrates a first stent 104 that is longer than the second stent 106. FIG. 8 illustrates a first stent 104 that is shorter than the second stent 106. It is understood that the first and second stents 104, 106 may be provided at different positions along a longitudinal axis relative to each other. For example, the first stent 104 may overhang the second stent 106 further on a first end than it does on a second end or may be flush with the second stent 106 on a first end and overhang on the second end. This facilitates a taper at the ends of the device. For example, the embodiment of FIG. 7 shows a taper into the lumen 107 which may facilitate minimal turbulence of the blood flow. FIG. 8 shows a taper toward the outer surface of the device. This may facilitate better placement at an aneurysmal site where the vessel is expanded outward and reduces pressure points on the aneurysmal site at the ends of the device 100.

[0060] Referring to FIG. 9, in some embodiments the graft 108 does not extend around the entirety of the device 100. For example, the graft 108 may be provided to extend from the first end 120 of the first stent 104 to the first end 124 of the second stent 106, along the second stent 106 (e.g., shown as interior to the second stent 106, but could be provided exterior) from the first end 124 to the second end 126, from the second end 126 of the second stent 106 to the second end 122 of the first stent 104. In some embodiments, the graft 108 may extend along at least a portion of the first stent 104 (e.g., shown as exterior to the first stent 104, but could be provided interior). This allows the graft 108 to define a seal at the ends 120, 122 of the first stent 104 with the surrounding vessel such that blood flow travels through the lumen 107 while excluding blood flow from the vessel wall where implanted and in the intermediate space 110 between the first and second stents 104, 106.

[0061] Referring to FIG. 10, in some embodiments an implantable medical device 200 may include a nitinol reinforced portion 202 and a vascular graft portion 204. The nitinol reinforced portion 202 is operable to expand up against the vessel wall and, in some embodiments, may compress a lesion of the vessel. The vascular graft portion 204 acts as the native vessel replacement through which fluids may flow. The vascular graft portion 204 is coupled to the nitinol reinforced portion 202 on both sides of the12DMS_US.367207894.1lesion. The vascular graft portion 204 is provided such that it is operable to expand and contract independently of the nitinol reinforced portion 202, and the nitinol reinforced portion 202 is provided such that it is operable to expand and contract independently of the vascular graft portion 204. In some embodiments, the implantable medical device 200 is operable to be deployed in sections such that ends may be deployed around a lesion and then a central portion is deployed along the lesion. In some embodiments, the nitinol reinforced portion 202 may include portions along a longitudinal length of the nitinol reinforced portion with differing compliance, which may be implemented to minimize hyperplasia or additional distention of the vessel wall.

[0062] Referring to FIG. 11 , in some embodiments an implantable medical device 300 may include have a different expanded diameters along the longitudinal length of the implantable medical device 300 in order to minimize compliance mismatch at the target site. For example, ends 302, 304 of the implantable medical device may include a first portion 310 that is operable to expand to a first diameter and a central portion 306 may include a second portion 312 that is operable to expand to a second diameter, where the second diameter is less than the first diameter. Additionally, the first and second portions 310, 312 may be provided to have different stiffness values. In some embodiments, the implantable medical device 300 may also include an inner layer 320 which acts as a conduit for fluid flow, where the inner layer 320 may either be nitinol reinforced or may include graft material without nitinol reinforcement (for example, see FIG. 12). In some embodiments, at least one of the portion 310, 312 may be balloon expandable, and the inner layer 320 may be self-expandable. In some embodiments, the inner layer 320 may wrap around the first and / or second end portions 310A, 310B (see FIG. 12). This facilitates a seam between the inner and outer layers 320 being configured to be positioned between the device and the vasculature in order limit intrusion between the inner and outer layers.

[0063] In some embodiments, a first end portion 310A of at least one of an inner layer (e.g., a first stent, graft, or stent graft) and outer layer (e.g., a second stent, graft, or stent graft) may be balloon expandable, and a second end portion 310B of at least one of an inner layer (e.g., a first stent, graft, or stent graft) and outer layer (e.g., a second stent, graft, or stent graft) may be self-expanding. In some embodiments, the first end portion 310A of at least one of outer layer (e.g., a first stent, graft, or stent graft) and inner layer (e.g., a second stent, graft, or stent graft) may be expanded before the second end portion 310B. In some embodiments, the second end portion 310B of at13DMS_US.367207894.1least one of first layer (e.g., a first stent, graft, or stent graft) and second layer (e.g., a second stent, graft, or stent graft) may be expanded after first end portion 31 OA. In some embodiments, an inner portion of at least one of first layer and second layer is expanded before first end portion 31 OA of at least one of first layer and second layer. In some embodiments, an inner layer may comprise only graft material (free of a reinforcing material such as nitinol or other metals), along a portion of the inner layer (e.g., only along end portions or only along central portions such as along a majority of aneurysm portion). In some embodiments, the first end portion 31 OA of a multi-layer endoprosthesis is expanded first, and the second end portion 31 OB is expanded second, and an inner portion is deployed with or without expansion. In some embodiments, the inner layer is expanded to provide fluid flow along length of endoprosthesis prior to expanding an anchor and at least one of the first or second end portions 31 OA, 31 OB. Once at least one of the first or second end portions 31 OA, 31 OB is expanded and anchored, the inner layer may be able to provide fluid flow free of or isolated from diseased tissue.

[0064] In some embodiments, the first and second stents 104, 106 are a combination of self-expanding and balloon-expandable. For example, in some embodiments, the first stent 104 is balloon-expandable and the second stent is selfexpanding. In some embodiments, the first stent 104 is self-expanding and the second stent is balloon-expandable. In some embodiments, the first and second stents 104, 106 are both self-expanding. In some embodiments, the first and second stents 104, 106 and both balloon-expandable.

[0065] A method of treating an aneurysm with an implantable medical device having multiple layers includes delivering an endoprosthesis to a treatment zone; expanding an outer layer first end portion to anchor an endoprosthesis on one side of treatment zone; expanding an outer layer second end portion on an opposite side of treatment zone; and expanding an inner layer of the implantable medical device to allow fluid flow along length of the implantable medical device.

[0066] A method of manufacturing an implantable medical device includes providing a first stent having a first diameter; positioning a second stent at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and coupling a graft to at least one of the first stent and to the second stent, the graft defining a lumen14DMS_US.367207894.1through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.

[0067] A biocompatible material for the graft components is typically used. The graft components may be configured to resist degradation, or be biodegradable in some examples. In certain instances, the graft components may include a fluoropolymer, such as a polytetrafluoroethylene (PTFE) polymer or an expanded polytetrafluoroethylene (ePTFE) polymer. In some instances, the graft components may be formed of, such as, but not limited to, a polyester, a silicone, a urethane, a polyethylene, a polyethylene terephthalate, or another biocompatible polymer, or combinations thereof. In some instances, bioresorbable or bioabsorbable materials may be used, for example a bioresorbable or bioabsorbable polymer. In some instances, the graft components can include Dacron, polyolefins, carboxy methylcellulose fabrics, polyurethanes, or other woven, non-woven, or film elastomers.

[0068] In addition, nitinol (NiTi) may be used as the material of the frame or stent components (and any of the frames discussed herein), but other materials such as, but not limited to, stainless steel, L605 steel, polymers, MP35N steel, polymeric materials, Pyhnox, Elgiloy, or any other appropriate biocompatible material, and combinations thereof, can be used as the material of the stent components. The superelastic properties and softness of NiTi may enhance the conform ability of the stent components. In addition, NiTi can be shape-set into a desired shape. That is, NiTi can be shape-set so that the frame tends to self-expand into a desired shape when the frame is unconstrained, such as when the stent components are deployed out from a delivery system.

[0069] The invention of this application has been described above both generically and with regard to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments without departing from the scope of the disclosure. Thus, it is intended that the embodiments cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.15DMS_US.367207894.1

Claims

WHAT IS CLAIMED IS:1 . An implantable medical device for bypassing an aneurysm, comprising: a first stent having a first diameter; a second stent positioned at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and a graft coupled to the first stent and to the second stent, the graft defining a lumen through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.

2. The implantable medical device of claim 1 , wherein the first stent includes a first transverse deformation resistance and the second stent includes a second transverse deformation resistance that is different than the first transverse deformation resistance.

3. The implantable medical device of claim 2, wherein the second transverse deformation resistance is greater than the first transverse deformation resistance.

4. The implantable medical device of claim 1 , wherein the first stent is configured to conform to a profile of the aneurysm.

5. The implantable medical device of claim 4, wherein the first stent is configured to exert a radial force sufficient to contact the aneurysm without exerting a significant force on the aneurysm.16DMS_US.367207894.

16. The implantable medical device of claim 1 , wherein the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

7. The implantable medical device of claim 6, wherein the intermediate space between the first and second stents when in the deployed configuration has a greater thickness than a thickness of the graft.

8. The implantable medical device of claim 1 , further comprising at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

9. The implantable medical device of claim 1 , wherein the first stent has a first longitudinal length and the second stent has a second longitudinal length, wherein the first longitudinal length is different from the second longitudinal length.

10. The implantable medical device of claim 1 , wherein the first stent and the second stent are a combination of balloon-expandable and self-expandable.

11. An implantable medical device for bypassing an aneurysm, comprising: a first stent having a first transverse deformation resistance, the first stent configured to conform a profile of the aneurysm;17DMS_US.367207894.1a second stent positioned at least partially within the first stent, the second stent having a second transverse deformation resistance, the second transverse deformation resistance being greater than the first transverse deformation resistance; and a graft coupled to the first stent and to the second stent.

12. The implantable medical device of claim 11 , wherein the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

13. The implantable medical device of claim 12, wherein the first and second stents are configured to define a variable thickness intermediate space between the first and second stents when the first and second stents are in a deployed configuration and the first stent is engaged with an aneurysmal portion of a vessel.

14. The implantable medical device of claim 11 , further comprising at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

15. The implantable medical device of claim 11 , wherein the first stent includes a helical stent.

16. The implantable medical device of claim 11 , wherein the first stent includes a ring stent.18DMS_US.367207894.

117. An implantable medical device for bypassing an aneurysm, comprising: a first stent having a first diameter, a first end, and a second end; a second stent positioned at least partially within the first stent, the second stent having a second diameter, a first end, and a second end, the second diameter being smaller than the first diameter; and a graft coupled to the first stent and to the second stent, the graft extending from the first end of the first stent to the second end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

18. The implantable medical device of claim 17, wherein the first stent includes a first transverse deformation resistance and the second stent includes a second transverse deformation resistance that is different than the first transverse deformation resistance.

19. The implantable medical device of claim 18, wherein the second transverse deformation resistance is greater than the first transverse deformation resistance.

20. The implantable medical device of claim 17, wherein the first stent includes a first end and a second end, the second stent includes a first end and a second end, and the graft extends from the first end of the first stent to the first end of the second stent, along the second stent, and from the second end of the second stent to the second end of the first stent.

21. The implantable medical device of claim 20, wherein an intermediate space between the first and second stents when in a deployed configuration has a greater thickness than a thickness of the graft.19DMS_US.367207894.

122. The implantable medical device of claim 17, further comprising at least one of an anchor or a bioadhesive configured to anchor the first stent to the aneurysm.

23. The implantable medical device of claim 17, wherein the graft extends between the first end of the first stent and the first end of the second stent, along the second stent, and between the second end of the second stent and the second end of the first stent.

24. An implantable medical device comprising: an outer layer including a graft material reinforced with a self-expanding material and having first and second longitudinal ends; and an inner layer including a graft material coupled to the outer layer at the first and second longitudinal ends of the outer layer, wherein a central portion of the inner layer is operable to expand and contract free of the outer layer.

25. A method of treating an aneurysm with an implantable medical device having multiple layers comprising: delivering an endoprosthesis to a treatment zone; expanding an outer layer first end portion to anchor an endoprosthesis on one side of treatment zone; expanding an outer layer second end portion on an opposite side of treatment zone; and expanding an inner layer of the implantable medical device to allow fluid flow along length of the implantable medical device.20DMS_US.367207894.

126. A method of manufacturing an implantable medical device, comprising: providing a first stent having a first diameter; positioning a second stent at least partially within the first stent, the second stent having a second diameter, the second diameter being smaller than the first diameter such that an intermediate space is defined between the first stent and the second stent when in a deployed configuration; and coupling a graft to at least one of the first stent and to the second stent, the graft defining a lumen through the second stent, wherein the lumen is configured to allow blood flow therethrough, and wherein the graft is configured to limit blood flow between the first stent and the second stent.21DMS_US.367207894.1

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