Patent ID: 12226329

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

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. Stated differently, other methods and apparatuses can be incorporated herein to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not all 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. Finally, although the present disclosure may be described in connection with various principles and beliefs, the present disclosure should not be bound by theory.

The terms “endoprosthetic device,” “endoprosthesis,” “vascular device,” and the like can refer, throughout the specification and in the claims, to any medical device capable of being implanted and/or deployed within a body lumen. In various embodiments, an endoprosthesis can comprise a stent, a stent-graft, a graft, a filter, an occluder, a balloon, a lead, and energy transmission device, a deployable patch, an indwelling catheter, and the like.

In addition, throughout this specification and claims, the delivery systems described herein can, in general, include an endoprosthesis constrained by a “covering member” or “sheath.” The covering member or sheath can, in various embodiments, comprise a sheet of material that is fitted about an endoprosthesis. As used throughout the specification and in the claims, the term “elongate member” can refer to a shaft-like structure such as a catheter, guidewire, introducer sheath, or the like. In various embodiments, an endoprosthesis can be mounted or loaded on a catheter, also referred to herein as an inner shaft, and, in a constrained diameter, fit within an introducer sheath, also referred to herein as an outer shaft.

Further, the term “distal” refers to a relative location that is farther from a location in the body at which the medical device was introduced. Similarly, the term “distally” refers to a direction away from a location in the body at which the medical device was introduced.

The term “proximal” refers to a relative location that is closer to the location in the body at which the medical device was introduced. Similarly, the term “proximally” refers to a direction towards a location in the body at which the medical device was introduced.

With continuing regard to the terms proximal and distal, this disclosure should not be narrowly construed with respect to these terms. Rather, the devices and methods described herein may be altered and/or adjusted relative to the anatomy of a patient.

As used herein, the term “constrain” may mean (i) to limit expansion, occurring either through self-expansion or expansion assisted by a device, of the diameter of an expandable implant, or (ii) to cover or surround, but not otherwise restrain, an expandable implant (e.g., for storage or biocompatibility reasons and/or to provide protection to the expandable implant and/or the vasculature).

As used herein, the term “vessel” refers to any luminal or tubular structure within the body to which these constructs can be utilized. This includes, but is not limited to, vascular blood vessels, vascular defects such as arteriovenous malformations, aneurysm, or others, vessels of the lymphatic system, esophagus, intestinal anatomy, sinuous cavity, urogenital system, or other such systems or anatomical features. Embodiments of the present invention are also suitable for the treatment of a malignant disease (e.g., cancer) within or associated with a vessel.

With initial reference toFIGS.1A and1B, an endoprosthesis100is illustrated. Endoprosthesis100may comprise, for example, an expandable stent-graft. In various embodiments, endoprosthesis100comprises a balloon expandable stent-graft. Although endoprosthesis100will be herein described as a balloon expandable stent-graft, endoprosthesis100may comprise other implantable, expandable medical devices, including a self-expandable stent-graft.

In various embodiments, stent-graft100comprises a stent member102. For example, stent member102can comprise one or more ringed stent elements104. As will be discussed in greater detail, ringed stent elements104can be positioned adjacent to one another along a longitudinal axis192of stent-graft100. In various embodiments, ringed stent elements104are evenly spaced from each other (i.e., uniformly distributed along the longitudinal axis). In other embodiments, one or more ringed stent elements104can be spaced apart from one another at different spacing along longitudinal axis192(i.e., non-uniformly distributed along the longitudinal axis). Any arrangement of ringed stent elements104is within the scope of the present disclosure.

Ringed stent elements104can comprise, for example, interconnected wire frames106arranged in a circular pattern. For example, ringed stent elements104can comprise a single row of interconnected wire frames106. One or more points118of a wire frame106can be in contact with and connected to points118of adjacent wire frames106. In various embodiments, ringed stent elements104can comprise a multiplicity of individual wire frames106formed independently of one another and connected to each other at one or more points118. In other embodiments, wire frames106are formed together as a single interconnected stent element104.

In various embodiments, ringed stent elements104can vary from each other in stiffness. For example, one or more ringed stent elements104having an increased stiffness can be located at a distal and/or proximal end of stent-graft100. Further, one or more ringed stent elements104having reduced stiffness can be located away from a distal and/or proximal end of stent-graft100. Any combination of ringed stent elements104, including multiple elements comprising different stiffness from each other, is within the scope of the present disclosure.

Wire frames106can comprise a polygon, such as, for example, a parallelogram. In various embodiments, wire frames106comprise a diamond shape. In other embodiments, wire frames106can comprise a square or rectangular shape. Any shape of wire frames106, including shapes that are not polygonal (such as ovoid or rounded shapes) or shapes that include undulations or bends, are within the scope of the present disclosure.

In various embodiments, wire frames106comprise a metal material. For example, wire frames106can comprise a steel, such as stainless steel or other alloy. In other embodiments, wire frames106can comprise a shape memory alloy, such as, for example, Nitinol. In yet other embodiments, wire frames106comprise a non-metallic material, such as a polymeric material. Further, the material of wire frames106can be permanent (i.e., non-bioabsorbable) or bioabsorbable. Any material of wire frames106having sufficient strength is within the scope of the present disclosure.

For example, ringed stent elements104can, for example, be cut from a single metallic tube. In various embodiments, ringed stent elements104are laser cut from a stainless steel tube. However, any manner of forming ringed stent elements104and/or wire frames106is within the scope of the present disclosure.

Endoprosthesis100can further comprise a graft member114. Graft member114may, for example, provide a lumen through which blood may flow from one end to another. Further, as will be discussed in greater detail, graft member114can comprise a number of layers or elements secured together to form a single graft member114.

Graft member114can comprise, for example, an inner graft element108. In various embodiments, stent member102is positioned concentrically around inner graft element108. For example, inner graft element108can comprise a layer of polymeric material having a luminal surface110that is in contact with blood flow within a vessel. Stent member102can surround, be in contact with, and provide support to inner graft element108.

In various embodiments, inner graft element108comprises a polymeric membrane capable of providing a bypass route to avoid vessel damage or abnormalities, such as aneurysms. Inner graft element108can comprise, for example, expanded polytetrafluoroethylene (ePTFE), polyester, polyurethane, fluoropolymers, such as perfluoroelastomers and the like, polytetrafluoroethylene, silicones, urethanes, ultra-high molecular weight polyethylene, aramid fibers, and combinations thereof. Other embodiments for a graft member material can include high strength polymer fibers such as ultra-high molecular weight polyethylene fibers (e.g., Spectra®, Dyneema Purity®, etc.) or aramid fibers (e.g., Technora®, etc.). Any graft member that is capable of providing a lumen for fluid flow within the body of a patient is within the scope of the present disclosure.

Inner graft element108can comprise, for example, one or more layers of a polymeric material. In various embodiments, inner graft element108comprises a polymeric material continuously wrapped over a substrate or mandrel to form a generally tubular member. For example, inner graft element108can be constructed with circumferential-, helical-, or axial-orientations of the polymeric material. “Orientations,” as used herein, generally refers to a directional property of a component or material (e.g., the polymetric material) often with reference to the longitudinal axis192. Orientations may also be used to refer to directional properties of certain features, such as, for example, orientations of the strength of the material.

In the embodiments discussed above, the polymeric material can be wrapped generally perpendicular to the longitudinal axis of the mandrel or substrate, i.e., circumferentially wrapped. In other embodiments, the material can be wrapped at an angle between greater than 0 degrees and less than 90 degrees relative to the longitudinal axis of the mandrel or substrate, i.e., helically wrapped. In yet other embodiments, the polymeric material can be wrapped generally parallel to the longitudinal axis of the mandrel or substrate, i.e., axially (or longitudinally) wrapped.

In various embodiments, inner graft element108may comprise a coating on luminal surface110. For example, a therapeutic agent such as antithrombogenic coating may be applied to luminal surface110. In various embodiments, a heparin coating is applied to luminal surface110.

Graft member114can further comprise, for example, an outer graft element112. In various embodiments, outer graft element112concentrically surrounds at least a portion of stent member102. For example, outer graft element112can concentrically surround stent member102and inner graft element108, essentially sandwiching ringed stent elements104of stent member102between the two graft elements108and112.

Similarly to inner graft element108, outer graft element112can comprise, for example, expanded polytetrafluoroethylene (ePTFE), polyester, polyurethane, fluoropolymers, such as perfluoroelastomers and the like, polytetrafluoroethylene, silicones, urethanes, ultra-high molecular weight polyethylene, aramid fibers, and combinations thereof. Outer graft element112can include high strength polymer fibers such as ultra-high molecular weight polyethylene fibers (e.g., Spectra®, Dyneema Purity®, etc.) or aramid fibers (e.g., Technora®, etc.). Further, outer graft element112can comprise one or more layers of polymeric material, and may be a tube or a wrapped element as described in connection with inner graft element108. In various embodiments, inner graft element108and outer graft element112comprise the same polymeric material. In other embodiments, inner graft element108and outer graft element112comprise different polymeric materials.

In such embodiments, inner graft element108and outer graft element112can orient and maintain the position of each of a multiplicity of ringed stent element104. For example, each ringed stent element104of stent member102can be positioned at a desired location along inner graft element108and then surrounded by outer graft element112. In various embodiments, after ringed stent elements104are properly positioned along inner graft element108, inner graft element108and outer graft element112are bonded together. For example, heat can be applied to bond inner graft element108and outer graft element112together, thereby maintaining the position of ringed stent elements104with respect to graft member114.

In various embodiments, ringed stent elements104are spaced apart at a desired distance from each other. For example, each of ringed stent element104can be positioned at between about 0 mm (i.e., one ringed stent element104abutting another) and about 4 mm apart from each other. In various embodiments, each of ringed stent element104can be between about 1.0 mm and about 2.0 mm apart from each other, and in particular embodiments are between about 1.1 mm and 1.5 mm from each other. Although described with reference to specific embodiments, ringed stent elements104of stent member102can be spaced any distance apart, including multiple different spacings within the same stent member102.

Further, in embodiments in which stent member102comprises spaced apart ringed stent element104, stent-graft100can comprise one or more intra-ring graft segments120. For example, intra-ring graft segments120can comprise the portion of inner graft element108and outer graft element112located between adjacent ringed stent element104. As will be discussed further, the properties of intra-ring graft segments120, including the length of segments120, can be manipulated to provide desired properties to stent-graft100.

In various embodiments, a first ringed stent element106acomprises a first apex120aand a second ringed stent element106bcomprises a second apex120b. First apex120aand second apex120bcan be adjacent to each other. For example, first ringed stent element106aand second ringed stent element106bcan be oriented with respect to each other such that first apex120aand second apex120bare in a common plane190orthogonal to a longitudinal axis192. Stated another way, first apex120aand second apex120bare in phase with each other. In other embodiments, first apex120aand second apex120bare not in a common plane orthogonal to longitudinal axis192(i.e., apices120aand120bare out of phase, or are otherwise not coplanar with each other). Although described with reference to specific embodiments, any orientation of ringed stent elements104, including multiple different orientations with the same medical device (i.e., stent-graft) is within the scope of the present disclosure.

Stent-graft100can be delivered to and deployed within a treatment area of a patient. For example, with initial reference toFIGS.2A and2B, stent-graft100can be prepared and mounted to a catheter assembly260comprising a catheter tube262with a continuous lumen264. A cover266can coaxially surround a balloon268, which is coupled to catheter tube262and continuous lumen264at or near the distal end of catheter tube262. Attachment of cover266to catheter tube262can be accomplished in various ways, including adhering the proximal and distal ends of cover266to catheter tube262using an adhesive, such as, for example, a cyanoacrylate adhesive. Further, polymeric tape and/or film may be used to secure the proximal and distal ends of cover266to catheter tube262.

Balloon268can comprise, for example a generally tubular shaped balloon capable of inflating within the vasculature of a patient upon pressurization. For example, a biocompatible fluid, such as, for example, water or saline, can be introduced into catheter tube262, pass through continuous lumen264and through an inflation port (not shown) in catheter tube262located at the interior of balloon268, and pressurize balloon268. As pressure to balloon268is increased, the diameter of balloon268is also increased.

Balloon268can comprise, for example, a non-compliant, generally inelastic balloon. In such embodiments, balloon268can comprise a material that is configured to allow balloon268to expand to a chosen diameter upon sufficient pressurization and remain at or near the chosen diameter under further pressurization until a burst pressure is reached, such as, for example, nylon, polyethylene, polyethylene terephthalate (PET), polycaprolactam, polyesters, polyethers, polyamides, polyurethanes, polyimides, ABS copolymers, polyester/poly-ether block copolymers, ionomer resins, liquid crystal polymers and rigid rod polymers.

In various embodiments, balloon268can comprise a compliant, relatively elastic balloon. In such embodiments, balloon268can comprise a material that is configured to allow balloon268to continuously increase in diameter as pressure to balloon268is increased, such as, for example polyurethanes, latex and elastomeric organosilicone polymers, such as, polysiloxanes. When a distension limit is reached, balloon268can rupture.

In yet other embodiments, balloon268comprises a semi-compliant balloon. In such embodiments, balloon268behaves in a combination of compliant and non-compliant attributes. Although described in connection with compliant and non-compliant embodiments, any material or configuration that allows balloon268to inflate in a predictable manner within the body of a patient, including in a combination of compliant and non-compliant behavior, is within the scope of the present disclosure.

With reference toFIG.3, in various embodiments, balloon268can comprise a plurality of pleats370. Pleats370can comprise, for example, folds or inflection points in the material of balloon268extending generally along at least a portion of longitudinal axis192. In such embodiments, balloon268comprises a generally tubular shape having one or more pleats370.

In various embodiments, balloon268can be coaxially surrounded by cover266. Cover266can comprise an inner surface that can substantially conform to an outer surface of balloon268, such that both balloon268and cover266comprise substantially the same shape, including when balloon268is deflated. However, in other embodiments, cover266can comprise a different shape or configuration from balloon268.

In various embodiments, cover266can comprise a plurality of pleats372. Similarly to balloon268, pleats372can comprise, for example, folds or inflection points in the material of cover266extending generally along at least a portion of the longitudinal axis. In such embodiments, cover266comprises a generally tubular shape having two or more pleats372. In various embodiments, cover266comprises the same number of pleats372as balloon268. In various embodiments, along at least a section of or the entire working length of balloon cover266, the inner surface of balloon cover266interfaces with the outer surface of balloon268in both the pleated, collapsed configuration and the un-pleated, inflated configuration. In other words, and as shown inFIG.3, the pleated portions of the cover266substantially correspond in their configurations to the corresponding pleated portions of the balloon268, and the non-pleated portions of the cover266substantially correspond in their configurations to the corresponding non-pleated portions of the balloon268.

Pleats370and372can be formed in cover266and balloon268simultaneously. For example, balloon268can be coaxially surrounded by cover266, and pleats370and372can then be formed in both balloon268and cover266, respectively.

In other embodiments, pleats372can be formed in cover266after pleats370are formed in balloon268. For example, a pre-pleated balloon268can be coaxially surrounded by cover266. In such embodiments, both cover266and pre-pleated balloon268can be inflated together to a working pressure, after which cover266and balloon268are subjected to a mechanical pleat forming process that can form, for example, the same number and configuration of pleats in cover266as in pre-pleated balloon268. While forming pleats372in cover266, both cover266and balloon268can be deflated and compacted for delivery into the body of a patient. Although described in specific embodiments, any manner of forming pleats in cover266is within the scope of the present disclosure.

In yet other embodiments, balloon268can comprise a plurality of pleats370and cover266can comprise no pleats372. In such embodiments, pleats370can be formed in balloon268, followed by cover266being placed coaxially around the outer surface of balloon268. Although described in connection with specific examples (i.e., balloon268and cover266both comprising pleats, or only balloon268or cover266comprising pleats), any configuration in which balloon268and/or cover266comprises a plurality of pleats is within the scope of the present disclosure.

Cover266can comprise, for example, a polymer such as, for example, expanded fluoropolymers, such as, expanded polytetrafluoroethylene (ePTFE), modified (e.g., densified) ePTFE, and expanded copolymers of PTFE. In various embodiments, the polymer can comprise a node and fibril microstructure. In various embodiments, the polymer can be highly fibrillated (i.e., a non-woven web of fused fibrils). Although described in connection with specific polymers, any material or configuration that allows cover266to inflate in a predictable manner within the body of a patient is within the scope of the present disclosure.

In various embodiments, cover266can comprise multiple layers of a polymeric material. For example, cover266can comprise a polymeric material continuously wrapped over a substrate or mandrel to form a generally tubular member. In various embodiments, cover266can be constructed with circumferential-, helical-, or axial-orientations of the polymeric material. In such embodiments, the polymeric material can be wrapped generally perpendicular to the longitudinal axis of the mandrel or substrate, i.e., circumferentially wrapped. In other embodiments, the material can be wrapped at an angle between greater than 0 degrees and less than 90 degrees relative to the longitudinal axis of the mandrel or substrate, i.e., helically wrapped. In yet other embodiments, the polymeric material can be wrapped generally parallel to the longitudinal axis of the mandrel or substrate, i.e., axially (or longitudinally) wrapped.

With reference toFIG.2B, cover266can, for example, have a length282that is greater than a length280of balloon268. In various embodiments, cover266is placed around balloon268such that a first cover end270and a second cover end272extend beyond a first balloon end274and second balloon end276. In such embodiments, a segment284of the material of cover266positioned at first cover end270or second cover end272can be compressed along longitudinal axis192(i.e., axially compressed). For example, with reference toFIGS.4A and4B, segment284of the material of cover266can be axially compressed (e.g., scrunched) at first cover end270and a segment286can be axially compressed at second cover end272.

As shown inFIGS.4A and4B, segment284and/or segment286are aligned with a first balloon shoulder290and/or a second balloon shoulder292. In other embodiments, the segments284and/or286are aligned with different portions of the balloon268. InFIGS.4A and4B, the first balloon shoulder290and/or second balloon shoulder292are cone-shaped shoulders. Although described with reference to a specific embodiment, any shape of balloon shoulder is within the scope of the present disclosure.

Segment284can, for example, be positioned such that it at surrounds at least a portion of first balloon shoulder290, and segment284can be positioned such that it at surrounds at least a portion of second balloon shoulder292. Providing additional axially compressed (e.g., scrunched) material around balloon shoulders (such as balloon shoulders290and292) can increase the thickness and/or density of cover266in the general area of the balloon shoulders. Furthermore, having additional axially compressed material of the cover266over the balloon shoulders allows for radial expansion of balloon268while limiting axial compression to the balloon during inflation. For example, without having those compressed portions, the shoulders of the balloon will inflate before the body of the balloon and cause axial compression of the balloon and endoprosthesis. But with the axially compressed material, the shoulders of the balloon can expand in a manner that causes less axial compression of the endoprosthesis (e.g., due to the changed angle between the expanded portion of the balloon and the unexpanded or less expanded portion of the balloon) until the pressure within the balloon as a whole is sufficient to more fully expand the cover and the endoprosthesis surrounding the body of the balloon. Further, increased thickness and/or density in the general region of balloon shoulders290and292can provide additional radial strength to the balloon shoulders to achieve a similar effect.

As previously described above, the balloon268can be inflated by providing pressurized fluid into balloon268.FIGS.5A-5Fillustrate one example of the cover266restricting expansion of balloon268to one desired inflation profile as the balloon268is inflated. The intermediate portion200of the stent-graft100imparts a resistance to expansion of the balloon268at the intermediate portion20of the stent-graft100, as well as at, or proximate to, the free ends196,198. The cover266also imparts a resistance to expansion of the balloon to reduce a difference in an expansion rate of the balloon268at the free ends196,198of the stent-graft100relative to an expansion rate of the balloon268at the intermediate portion200of the stent-graft100so as to reduce longitudinal compression of the stent-graft100as the balloon268expands the stent-graft100from its undeployed state (FIG.5A) to its deployed state (FIG.5F). In some embodiments, the cover266acts to equalize the expansion rate of the balloon268at the intermediate portion200of the stent with the expansion rate of the balloon at, or proximate to the free ends196,198(e.g., proximate or at the shoulders).

For example, in some embodiments axially compressed segments284and/or286are configured to provide additional resistance to the expansion of balloon shoulders290and292, causing a middle portion294of balloon268to inflate more readily than it would without such segments284and286, which limits the expansion of the balloon shoulders to more closely match the expansion of the middle portion294of the balloon268. Axially compressed segments284and/or286can also substantially impede inflation of balloon shoulder290and/or292. In various embodiments, this has the effect of controlling the extent of balloon inflation in these regions which, in turn, controls the expansion profile of balloon268and/or stent-graft100.

In various embodiments, the expansion of balloon268can be controlled by covered segments284and/or286in a manner that may reduce undesirable expansion characteristics of stent-graft100. For example, covered segments284and/or286may reduce the degree of foreshortening of stent-graft100during expansion. In particular, segments284and/or286may be configured to force the balloon to into a specific inflation profile in which axial forces resulting from inflating balloon shoulders are significantly reduced, for example, due to the diminished angle between the shoulder portions of the balloon and the middle portion of the balloon or the stent-graft. Further, covered segments284and/or286may reduce or prevent stacking (e.g., reduction of spacing between ringed stent elements106during expansion) of stent-graft100.

With reference toFIGS.2A and2B, after balloon268is surrounded by cover266, stent-graft100can be loaded on to balloon268and cover266. For example, stent-graft100can be positioned to concentrically surround a portion of balloon268and cover266. In various embodiments, once stent-graft100is properly positioned around balloon268and cover266, stent-graft100is radially compressed to an undeployed diameter242. For example, stent-graft100can be compacted to undeployed diameter242to reduce the profile of stent-graft100during implantation within a treatment area. Further, stent-graft100can be compacted onto balloon268and cover266so as to resist movement of the stent-graft on balloon268prior to deployment.

In various embodiments, upon compaction, stent-graft100can imbed itself into cover266. For example, by imbedding itself into cover266, stent-graft100may exhibit improved stent retention. Such improved stent retention may, for example, assist in maintaining proper positioning of stent-graft100relative to cover266and/or balloon268during deployment to the treatment area of a patient.

Another way to limit any reduction in the length of the endoprosthesis (e.g., as measured between one free end196and the opposite free end198) between its compressed and expanded configurations is by altering the position and/or orientation of the ringed stent elements104of a stent member102. In particular, in some embodiments the position and/or orientation of one or more ringed stent elements104of stent member102can be altered prior to compaction of stent-graft100. For example, the distance between two or more adjacent ringed stent element104may be reduced prior to compaction of stent-graft100. For more particular examples, one or more ringed stent elements104can be moved so that they are each less than about 1 mm apart from each other or even so that they are in contact with one another (i.e., spaced 0 mm apart from each other).

In other embodiments, the position and/or orientation of ringed stent elements104may be altered after compaction of the stent-graft100. For example, and with reference toFIG.2A, stent-graft100has a length that can be changed by reducing the longitudinal spacing of two or more ringed stent element104. Reducing the longitudinal spacing between adjacent ringed stent element104can, for example, create stored longitudinal length that is recovered when the stent element104is expanded into its deployed state. For example, stored longitudinal length may be defined as the length or segment of graft material of intra-ring graft segments120axially compressed between adjacent ringed stent elements104which is retrieved (i.e., axially expanded) upon expansion and deployment of stent-graft100. The “undeployed length” of the stent-graft100generally refers to the stent-graft100in the compressed state prior to delivery and the “deployed length” of the stent-graft100generally refers to the stent-graft100in the expanded state. In some embodiments, changing the spacing of the ringed stent elements104creates a new length that may be referred to as the undeployed length (e.g., length240inFIG.2A).

Stated another way, reducing the spacing between adjacent stent elements104can axially compress or scrunch intra-ring graft segments120. By creating stored length by axial compression, the outside diameter of the stent-graft100is not increased. By not increasing the diameter of the device while creating stored length, the transverse-cross section of the device remains minimal and thus does not adversely affect delivery of the stent-graft through the vasculature. At the same time, recovery of the stored length increases the ability of the stent-graft to reduce or offset any loss of length, e.g., due to axial compression forces from inflating the balloon.

Upon delivery of stent-graft100to the treatment area of a patient, stent-graft100can be deployed. In various embodiments, stent-graft100is deployed by inflating balloon268to a desired diameter, thereby increasing the diameter of stent-graft100from an undeployed diameter242to a deployed diameter146. This process further increases the length of the stent-graft from the undeployed length240to a deployed length148. After balloon268is sufficiently inflated, so that deployed diameter146is achieved, balloon268can be deflated, allowing for removal of catheter assembly260from the body of the patient.

Deployed length148can, for example, be less than undeployed length240. For example, deployed length148can be about 60% to about 95% of undeployed length240, and further, about 80% to about 90% of undeployed length240. Testing has shown that certain embodiments have achieved deployed lengths148greater than 99% the undeployed length, thus demonstrating a foreshortening length of less than 1%. The ability of a stent-graft to achieve a high percentage of its undeployed length is also referred to herein as longitudinal efficiency.

Expanding stent-graft100from the undeployed configuration to the deployed configuration can also, for example, increase an internal angle of one or more wire frames106of ringed stent elements104. For example, when stent-graft100is in the deployed configuration, internal angle188of wire frames106of ringed stent elements104can be between about 70 and 110 degrees, and further, between about 80 and 100 degrees.

Example 1—Bend Radius

Various stent-grafts in accordance with the present disclosure were tested to evaluate their flexibility in the deployed configuration. Specifically, the stent-grafts were tested to determine the bend radius that the stent-graft can accommodate without kinking and can recover its original size and shape after testing. Kinking occurs at the point at which the stent-graft exhibits a diameter reduction of greater than 50%, or where it cannot recover its original size and shape after testing.

The stent-grafts were tested according to ISO25539-2 (2009), section D.5.3.6, method A with the following exceptions: 1) testing was not performed in a tube of the minimum nominal indicated vessel diameters or at maximum indicated vessel diameter, and 2) overlapped condition testing was not performed. The stent-grafts comprise stainless steel ringed stent elements spaced apart at approximately 0.5 mm to 1.5 mm from each other. The stents were approximately 59 mm long. The inner and outer graft elements comprised ePTFE, and the stent-grafts were mounted on a nylon balloon surrounded by an ePTFE cover having scrunched proximal and distal ends. The results of the bend radius testing are summarized below in Table 1.

TABLE 1BendRadius (mm)Nominal Diameter (mm)510Mean47Maximum48Minimum46Sample Size1010

Example 2—Radial Strength

Various stent-grafts in accordance with the present disclosure were tested to evaluate their radial strength in the deployed configuration. Specifically, the stent-grafts were tested to determine the radial compressive pressure at which the stent-grafts would become irrecoverably deformed.

The stent-grafts were tested according to ISO25539-2:2009, section D.5.3.4 with the following exceptions: 1) pressure was reported in pounds per square inch, and 2) testing was conducted until a 50% reduction in the nominal device diameter was achieved.

The stent-grafts comprise stainless steel ringed stent elements spaced apart at approximately 0.5 mm to 1.5 mm from each other. The stents were approximately 59 mm long. The inner and outer graft elements comprised ePTFE, and the stent-grafts were mounted on a nylon balloon surrounded by an ePTFE cover having scrunched proximal and distal ends. The results of the radial strength testing are summarized below in Table 2.

TABLE 2RadialStrength (psi)Nominal Diameter (mm)510Mean18.311.9Maximum20.912.6Minimum14.411.2Sample Size88

While particular embodiments of the present invention have been illustrated and described herein, the present invention should not be limited to such illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims.

Numerous characteristics and advantages have been set forth in the preceding description, including various alternatives together with details of the structure and function of the devices and/or methods. The disclosure is intended as illustrative only and as such is not intended to be exhaustive. It will be evident to those skilled in the art that various modifications may be made, especially in matters of structure, materials, elements, components, shape, size, and arrangement of parts including combinations within the principles of the invention, to the full extent indicated by the broad, general meaning of the terms in which the appended claims are expressed. To the extent that these various modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.