Patent Publication Number: US-2022226137-A1

Title: Endoprosthesis delivery systems with deployment aids

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/855,568, filed Dec. 27, 2017, which a divisional of U.S. patent application Ser. No. 14/198,037, filed Mar. 5, 2014, now U.S. Pat. No. 9,855,160, issued Jan. 2, 2018, which claims priority to Provisional Application No. 61/782,134, filed Mar. 14, 2013, all of which are herein incorporated by reference in their entireties for all purposes. 
    
    
     FIELD 
     The present disclosure generally relates to endoprostheses for treating diseases of the vasculature and similar anatomies, and more particularly to endoprosthesis delivery systems for preventing entanglement of covering members with such endoprostheses. 
     BACKGROUND 
     Many endoprostheses (or endoprosthetic devices), such as, for example, stent-grafts, are constructed to reinforce, replace, bridge, or otherwise treat a part of a blood vessel. An endoprosthesis may thus guide blood flow through a lumen defined by a generally tubular interior of such a vessel. Other tubular endoprostheses are designed for use in other body regions, for example, the esophagus, ureters, gastrointestinal tract and various ducts. In many cases, endoprostheses are constrained within a covering member or sheath, and when the covering member is removed, as during deployment, the devices expand, are expanded under force or self-expand to assume a larger diameter. From time to time, however, as a covering member is removed, the member may snag, catch, or become entangled on the endoprosthesis. Thus, improved endoprosthesis delivery systems are desirable. 
     SUMMARY 
     The present disclosure includes an endoprosthesis delivery system comprising an elongate member, such as a catheter, an endoprosthesis, a covering member disposed about the endoprosthesis, and at least one flexible element situated between the endoprosthesis and the covering member. The covering member can extend beyond an end of the endoprosthesis. In operation, as the covering member is removed, the flexible element can guide the covering member over the end of the endoprosthesis to prevent entanglement between the end of the endoprosthesis and the covering member. 
     The present disclosure further includes an endoprosthesis delivery system comprising an elongate member having a slip resistant section or material, an endoprosthesis, and a covering member. The slip resistant material can comprise a gummy or mildly sticky material or a compressible material as described, and it can extend beyond a distal and/or proximal end of the endoprosthesis. In operation, as the covering member unravels or is otherwise removed to release the endoprosthesis, the slip resistant material can impede bunching of the cover. This can, in turn, prevent, or help to prevent, entanglement between the covering member and the endoprosthesis. 
     The present disclosure further includes an endoprosthesis delivery system comprising an elongate member, an endoprosthesis having a distal and/or proximal edge, an end cap adjacent to one of these edges, and a covering member. The covering member can extend beyond an end of the endoprosthesis and over a surface of the end cap. In operation, as the covering member is removed, the end cap can prevent the covering member from becoming entangled with an edge of the endoprosthesis. Rather, the covering member can follow the end cap as a guide over the edges of the endoprosthesis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein: 
         FIG. 1  illustrates a perspective view of an endoprosthesis delivery system; 
         FIG. 2  illustrates a magnified perspective view of an endoprosthesis delivery system; 
         FIG. 3  illustrates a perspective view of an endoprosthesis delivery system, including a line along which a cross-sectional view is to be taken; 
         FIG. 4  illustrates a cross-sectional view of an endoprosthesis delivery system taken along the line shown in  FIG. 3 ; 
         FIG. 5  illustrates a perspective view of an endoprosthesis delivery system without a compressible material; 
         FIG. 6  illustrates a perspective view of an endoprosthesis delivery system with a compressible material; 
         FIG. 7  illustrates a perspective view of an endoprosthesis delivery system, including a line along which a cross-sectional view is to be taken; 
         FIG. 8  illustrates a cross-sectional view of an endoprosthesis delivery system taken along the line shown in  FIG. 7 ; 
         FIG. 9  illustrates a magnified and cropped cross-sectional view of an endoprosthesis delivery system taken along the line shown in  FIG. 7 ; 
         FIG. 10  illustrates a perspective view of an endoprosthesis delivery system in the process of deploying an endoprosthesis; 
         FIG. 11  illustrates a magnified perspective view of an endoprosthesis delivery system in the process of deploying an endoprosthesis; 
         FIG. 12A  illustrates perspective view of an endoprosthesis delivery system including a slip resistant material; 
         FIG. 12B  illustrates a perspective view of an endoprosthesis delivery system including a flexible, longitudinally compressed polymeric member; 
         FIG. 13A  illustrates a perspective view of a method of manufacturing an endoprosthesis delivery system comprising rolling a sheet of compliant material about a mandrel; 
         FIG. 13B  illustrates a perspective view of a method of manufacturing an endoprosthesis delivery system comprising curing a rolled sheet of compliant material; 
         FIG. 13C  illustrates a perspective view of a method of manufacturing an endoprosthesis delivery system comprising longitudinally compressing a rolled sheet of compliant material to form a slip resistant material; 
         FIG. 14  illustrates a perspective view an endoprosthesis delivery system having an end cap and a tapered end cap; 
         FIG. 15  illustrates a perspective view of an endoprosthesis delivery system in a post-deployment stage; 
         FIG. 16  illustrates a cross-sectional view of a tapered end cap; 
         FIG. 17  illustrates a process for loading an endoprosthesis on an inner shaft of an elongate member and within a covering member; 
         FIG. 18 a    illustrates a perspective view of an endoprosthesis delivery system prior to constraining an endoprosthesis in which a flexible element is fully opened; 
         FIG. 18 b    illustrates a shape of a flexible element when viewed axially; 
         FIG. 18 c    illustrates a constrained endoprosthesis with a flexible element placed between an endoprosthesis and an endoprosthesis covering element; 
         FIG. 19  illustrates a cross-sectional view of an endoprosthesis delivery system; 
         FIG. 20A  illustrates a film tube capable of forming a portion of an endoprosthesis delivery system; 
         FIG. 20B  illustrates a film tube including a plurality of slits for forming a portion of an endoprosthesis delivery system; and 
         FIG. 21  illustrates an endoprosthesis delivery system. 
     
    
    
     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, 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. The covering member or sheath can, in various embodiments, comprise a plurality of knitted fibers located about the endoprosthesis. These fibers can, for example, comprise a woven warp knit or knit-braid, as described in U.S. Pat. No. 6,315,792 to Armstrong et al., issued Nov. 13, 2001, entitled “Remotely removable covering and support,” which is incorporated herein, in its entirety, by reference. The covering member can be coupled to a pull line extending down the length of the catheter, which a physician can pull to facilitate uncovering the endoprosthesis. 
     For example, a covering member comprising a plurality of fibers can be coupled to a pull line, which a physician can pull to unravel the plurality of fibers. Thus, the covering member can be characterized as “unzipping”, in that the pull line causes the covering member to open or unzip along a straight line. In addition, in various embodiments, a covering member can be unzipped, first, along a proximal vector and, second, along a distal vector. In various embodiments, a covering member can be unzipped along a longitudinal vector running substantially parallel to the longitudinal axis of an elongate member. 
     Covering members can become caught on the endoprosthesis during deployment. For example, the covering member comprising a plurality of fibers can extend beyond an end or edge of an endoprosthesis, and as the covering member begins to be removed, e.g., unzipped, along a particular vector (e.g., a longitudinal vector), the member can become entangled with the end of the endoprosthesis. For example, the covering member can become entangled with one or more apices comprising the end of the endoprosthesis. Although the following description may often refer to a covering member comprising a plurality of fibers; in various embodiments, a covering member can comprise any of a variety of covers or sheaths capable of constraining 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, throughout this specification and in the claims, 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, throughout the specification and in the claims, 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). 
     Accordingly, while specific embodiments are described in greater detail below, in general, the present disclosure will focus primarily upon endoprosthesis delivery systems and methods, and in particular, systems and methods for delivery of endoprostheses covered by a covering member combined with mechanisms that prevent snagging or entanglement between the covering member and the endoprosthesis. 
     In various embodiments, an endoprosthesis delivery system can comprise an elongate member, such as a catheter, an endoprosthesis, a covering member disposed about the endoprosthesis, and at least one flexible element situated between the endoprosthesis and the covering member. The covering member can extend beyond an end of the endoprosthesis. The endoprosthesis delivery system can further comprise a compressible material section of the elongate member extending at least beneath an end of the stent. 
     In operation, as the covering member unravels, the flexible element can guide the covering member over the end of the endoprosthesis to prevent a catch, snag, or entanglement between the end of the endoprosthesis and the covering member. For example, in an embodiment where the covering element comprises a plurality of fibers and is removed in a proximal direction, the flexible element can overlay a distal edge of the endoprosthesis, and as the covering member unravels, one or more fibers can ride over the flexible element. Similarly, in another embodiment where the covering member is removed in a distal direction, the flexible element can guide one or more fibers over a proximal edge of the endoprosthesis. Thus, the flexible element can prevent or reduce the likelihood of the covering member becoming caught on the endoprosthesis during deployment of the device. Optionally, the flexible element can extend through an opening at least partially defined by an edge, such as an apex, or an aperture formed in a graft member. 
     In the same or different embodiments, an endoprosthesis delivery system can comprise an elongate member, such as a catheter, having a slip resistant section or material, an endoprosthesis, and a covering member or sheath. The slip resistant material can comprise a gummy or sticky material, a compressible material, or a longitudinally compressed material (or various combinations thereof) that is located on a section of catheter adjacent a distal and/or proximal end of the endoprosthesis. The sheath, as above, can comprise a knitted plurality of fibers and can extend beyond the distal and/or proximal end of the endoprosthesis and be collocated with the slip resistant section. 
     During deployment, as the sheath unravels to release the endoprosthesis, the slip resistant material can impede bunching of the sheath fibers. This can, in turn, prevent, or help to prevent, a snag or entanglement between the sheath and the endoprosthesis. For example, the portion of the slip resistant material that extends beyond the distal and/or proximal end of the endoprosthesis can act as a mild adhesive between the sheath and the catheter, so that as the pull line coupled to the sheath is retracted (e.g., to initiate deployment), the sheath does not merely follow the motion of the pull line and slide down an otherwise relatively smooth surface of the catheter, bunching as it slides, to eventually become hung or entangled with an end of the endoprosthesis. Rather, the slip resistant material can releasably or mildly bind the sheath to the catheter, so that pulling of the pull line does not result in bunching that could lead to a failed deployment. In various embodiments wherein the sheath comprises a plurality of fibers, the fibers can partially embed into the slip resistant material as the pull line is pulled. 
     In different or the same embodiments, an endoprosthesis delivery system can comprise an elongate member, for example a catheter, an endoprosthesis having a distal and/or proximal edge, an end cap adjacent to one of these edges, and a covering member, such as a knitted covering member as described above. The covering member can extend beyond an end of the endoprosthesis and over a surface of the end cap. 
     By way of example, in operation, as the covering member comprising a plurality of fibers unravels to uncover or release the endoprosthesis from a delivery and/or constrained diameter, the end cap can prevent the fibers from becoming hung or entangled with an edge of the endoprosthesis. Rather, the covering member can follow the end cap surface guiding it over the edges of the endoprosthesis. 
     Now, as shown with reference to  FIG. 1 , and more closely with reference to  FIG. 2 , an endoprosthesis delivery system  100  can comprise, in various embodiments, an elongate member  102 , an endoprosthesis  104 , a covering member  106 , and/or a catheter tip or “olive”  108 . Further, as shown with reference to  FIGS. 1-4  (and most clearly with reference to  FIG. 4 , which as shown at  FIG. 3 , illustrates a cross-sectional view of the delivery system  100 ), a delivery system  100  can comprise one or more flexible elements  110   a - 110   h . In various embodiments, the distal edge of the covering member  106  can extend to a location just proximal of the ends of the flexible elements  110   a - 110   h , for example, between the ends of elements  202   a - 202   e  (described below) and the distal ends of flexible elements  110   a - 110   h . In certain embodiments, for example where covering member  106  comprises a plurality of woven warp knit or knit-braid fibers, the distal and/or proximal end regions of covering member  106  can be longitudinally compressed against the end(s) of endoprosthesis  104 . This helps to reduce variability of such compression which might otherwise occur to a more random extent when the endoprosthesis delivery system  100  is passed through a hemostasis valve and/or when covering member  106  is deployed via a pull line. 
     Referring now mainly to  FIG. 2 , each of the flexible elements  110   a - 110   h  can extend over, or overlap or overlay, a distal edge of the endoprosthesis  104 . For example, the endoprosthesis  104  can comprise a stent or stent graft, which can, in either case, include one or more stent elements  202   a - 202   e , e.g., stent rings or windings. Each element  202   a - 202   e  can comprise a plurality of apices, and, with regard to a stent element located at a distal end (or a proximal end, in certain embodiments) of the endoprosthesis  104 , such as stent element  202   a , the flexible elements  110   a - 110   h  can overlap the apices formed in the stent element  202   a . Similarly, where the endoprosthesis  104  comprises a stent graft, the flexible elements  110   a - 110   h  can overlay the distal edge, e.g., an apex, and optionally extend through the graft material by way of one or more openings formed (e.g., via a laser cutting tool) in the graft material. 
     While the figures show eight flexible elements, in various embodiments, the number of flexible elements can correspond to a number of apices associated with an endoprosthesis  104 . Thus, there can be fewer or greater than eight flexible elements  110   a - 110   h . Moreover, two or more flexible elements can overlay a single apex. 
     In various embodiments, and with reference to  FIGS. 20A and 20B , a flexible element  110   a - 110   h  can be formed by cutting or incising a film tube to create a plurality of slits within the film tube. A film tube having a plurality of slits is shown with respect to  FIG. 20B , and as shown, the region between each slit can comprise one of the plurality of flexible elements  110   a - 110   h . Similarly, as shown in  FIG. 21 , in other embodiments, the flexible element(s)  2110  formed from a film tube having a plurality of longitudinal slits shown in  FIG. 20B  can be secured to the distal region of the elongate member  2102 , distal to the distal edge of the endoprosthesis  2104 . For example, one or more flexible elements  2110  can be secured to a catheter olive  2108 , or be positioned proximal thereto and extend proximally to overlay the edge of the endoprosthesis  2104 , and optionally extend through openings formed adjacent to apices of the stent elements  2212 . 
     As shown with respect to  FIG. 4 , the endoprosthesis delivery system  100  can further comprise a material  402  compressible in the z-axis, e.g., a material that comprises some loft or a soft material, such as a silicone, ePTFE, or polyurethane foam. The “z-axis” can refer to the axis which extends through the thickness of the material. The compressible material  402  can surround the elongate member  102 . The z-axis compressible material  402  extends on a section of the elongate member, wherein the section is collocated at an edge of the endoprosthesis  104  and extends at least a small distance distally and/or proximally so that the edge of the tubular endoprosthesis, whether a proximal and/or distal edge, can at least partially embed itself into the compressible material  402 . This can serve to prevent the covering member becoming entangled with the endoprosthesis from the underside thereof. 
     As such, the compressible material  402  can comprise any material in which an endoprosthesis  104  can be at least partially embedded when in a delivery configuration. For example, the compressible material  402  can be capable of compressing and/or densifying in response to the application of a radially compressive force, as described above. In various embodiments, the compressible material  402  can comprise any of the following and/or any combination of the following substances: silicones, polyurethane, polytetrafluoroethylene (PTFE), porous polymers, such as expanded polytetrafluoroethylene (“ePTFE”), fluorinated ethylene propylene (FEP), various foams, any polymeric material, any fluoropolymer based material, and the like. The compressible material may be in the form of a balloon, of complaint, semi-compliant, or non-compliant type. When slightly inflated, the balloon will serve the function of the compliant material. In addition, a balloon that is slightly longer than the endoprosthesis  104  can form one or more compliant olives at one or both ends of the endoprosthesis  104 . Further, in various embodiments, a covering member  106  can be used to adjust the length of a balloon at the end of the endoprosthesis  104 . 
     In various embodiments, the flexible element(s)  110  can comprise a compliant member. The compliant member can be sufficiently compliant to conform to a distal edge profile of an endoprosthesis. The flexible element(s)  110  can further be a slender, elongated member. For example, flexible element(s)  110  can comprise a filament or thread. The flexible element(s) can possess any variety of cross-sections, e.g., a circular, oval, square, elliptical, rectangular, polygonal, generally flat, or any variety of cross-sections. Moreover, in various embodiments, the flexible elements  110  can comprise a tube, tube like structure, or sock. The flexible element(s) can be manufactured by methods typically used to make fibers and the like and by injection molding, extrusion, and/or calendaring. 
     A flexible element is secured to the elongate member  102 . For example, a flexible element  110  can be coupled to elongate member  102  at a location proximal to the distal edge and extend through an opening to overlay the distal edge, as shown with reference to  FIG. 5 . The flexible element in this example is of an appropriate length so that the free end (the end not secured to the elongate member  102 ) is drawn out of the opening in an apex formed in the stent ring or winding as the endoprosthesis  104  deploys. 
     In order to secure the flexible element, as shown with respect to  FIG. 6 , each flexible element  110   a - 110   h  can optionally extend into or beneath the compressible material  402 . The flexible elements  110   a - 110   h  can, in this manner, be secured to the elongate member as each element extends proximally there under. This feature is illustrated in additional detail with respect to  FIGS. 7-9 . In particular,  FIGS. 8 and 9  show cross-sectional views, taken along the line shown in  FIG. 7 , of an endoprosthesis delivery system  100 . In these Figures, several flexible elements  110   a  and  110   d  can be seen overlapping their respective apices and extending in a proximal direction underneath the surface of the compressible material  402 . 
     As shown in  FIGS. 18A-18C , in other embodiments, the flexible element  110  can be formed as a thin, flexible disc  1802  which when attached to a catheter olive  108  or when positioned just proximal thereto as shown can be everted toward the endoprosthesis  104  to cover at least a portion of its edge.  FIG. 18A  shows the delivery system  100  with a distal olive  108 , elongate member  102  and endoprosthesis  104  all in an unconstrained state, e.g., before a covering member  106  is applied. A front view of disc  1802 , having a center hole  1804  for fitting with elongate member  102  is shown in  FIG. 18B . Disc  1802  is shown in  FIG. 18C  as having been everted over the distal edge of endoprosthesis  104  and covering member  106  applied to constrain both endoprosthesis  104  and disc  1802 . Upon removal of covering member  106 , disc  1802  prevents covering member  106  from becoming caught on the distal edge of endoprosthesis  104  and as endoprosthesis  104  expands, the edges of disc  1802  are rotated outward. Disc  1802  can be made of any sufficiently flexible material, e.g., an elastomer such as silicone or thin sheet of a polymer such as ePTFE, so that the readily rotates away from the endoprosthesis  104 . Disc  1802  can be made of different shapes of any sufficiently flexible material, e.g. a sheet, tube of circular cross section or other non uniform cross sections. 
     In further embodiments, disc  1802  may be provided with longitudinal weak zones or perforations which fracture upon expansion of endoprosthesis  104 . In other embodiments, disc  1802  may feature a series of longitudinal cuts made around its circumference extending radially toward, but not extending to, the center hole  1804 . Such cuts form a plurality of strands about at least a part of the disc&#39;s circumference. These strands can then be everted over the distal end of endoprosthesis  104  and serve to prevent covering member  106  from entangling with the distal edge thereof upon its rem oval. 
     At the point of attachment, flexible element can easily pivot or bend at its base, i.e., the point of catheter attachment, facilitating the flexible element sweeping through a wide range of motion. For example, the flexible element is capable of sweeping through at least a 90 degree arc along the longitudinal axis, at least a 180 degree arc along the longitudinal axis, at least a hemispherical range, or more. 
     With reference now to  FIGS. 10 and 11 , an endoprosthesis  104  can be delivered as shown. The covering member  106  can be unstitched, unzipped, unraveled, drawn away, or otherwise removed, as described herein, from the endoprosthesis  104 . Covering member  106  is shown as being fully retracted for clarity but it will be understood that endoprosthesis  104  can progressively expand during gradual or stepwise withdrawal of covering member  106 . As the covering member  106  is removed from an end of the endoprosthesis  104  (e.g., as depicted, from a distal end or region of the endoprosthesis  104 ), the flexible elements  110   a - 110   h  guide the retracting covering member  106  over the distal edge, e.g., at the apices, at the distal (or proximal, in other configurations) end of the endoprosthesis  104 . As the covering member  106  uncovers the tubular endoprosthesis, the flexible elements  110   a - 110   h  can be pushed outward by the expanding endoprosthesis, and optionally retracted from an opening. This feature can be of particular help where, for example and as described above, the covering member  106  is of a braided or knitted structure, such a structure having openings capable of becoming entangled snagging, or catching on one or more apices as the covering member  106  is made to unzip through the proximal motion of a pull line coupled to the member  106 . 
     In various embodiments, and referring to  FIG. 12A , an endoprosthesis delivery system  1200  can include an elongate member, an endoprosthesis  104 , a covering member, as described above, and a slip resistant portion or material  1210  located about a section of catheter adjacent the endoprosthesis  104 . 
     In various embodiments, the slip resistant material  1210  can be located on the elongate member  1202  adjacent to and/or underneath the endoprosthesis. As shown in  FIG. 12A , slip resistant material  1210  is positioned proximal of the olive  108 , extending under endoprosthesis  104  and terminating proximal thereto. In various embodiments, slip resistant material may extend a longer or shorter distance, e.g., it may extend proximal of the olive  108  to just under the distal edge of endoprosthesis  104  or abut the distal edge of the endoprosthesis. 
     In various embodiments, the slip resistant material  1210  can comprise a z-axis compressible material, as described above. In same or different embodiments, the slip resistant material  1210  can be longitudinally compressed, as shown, so that its surface is not smooth, but wrinkled or ribbed, giving it a more “abrasive” surface to resist bunching of the covering member. Further, in same or different embodiments, the slip resistant material  1210  can be gummy or mildly sticky or adhesive. Slip resistant material can be made of a variety of materials such as adhesives, materials coated with adhesives, spongy materials possessing loft, foams, or materials that are compressible. One such material can be made of a polymer such as PTFE or an ePTFE. In certain embodiments, slip resistant material  1210  may be incorporated with or serve as the olive  108 . In such embodiments, the distal end of the endoprosthesis  104  will extend over at least a portion of the olive  108 . Where slip resistant material  1210  forms the olive  108 , said material can comprise a foam. 
     During deployment, the covering member (not shown) can be removed, e.g., by unraveling or unzipping, to release the endoprosthesis  104  from a constrained configuration. In various embodiments, as the covering member unzips, the covering member can stick to and/or at least partially embed into the slip resistant material  1210 , for example in a distal portion or segment  1212  of the slip resistant material  1210 , so that the covering member is impeded from bunching as a pull line coupled to the covering member is pulled to deploy or uncover the endoprosthesis. A cross-sectional illustration of a covering member embedded within a slip resistant or otherwise compressible material is shown at  FIG. 19 . With reference to  FIG. 19 , as shown, one or more sheath or covering member fibers  106   a  and/or  106   b  can be embedded within a compressible material  402 . This can, in turn, prevent, or help to prevent a snag or entanglement between the covering member and the endoprosthesis  104 . In various embodiments, slip resistant material  1210 , in particular segment  1212 , can function to elongate along the outer radius when bent and thus minimizing a gap formed between the proximal face of olive  108  and the distal edge of the endoprosthesis  104 . If the covering member extends proximally or over olive  108 , segment  1212  will prevent covering member from slipping into said gap. If this occurs, covering member has an increased likelihood of becoming caught on the endoprosthesis  104 . 
     With particular attention to the interface between the edge of the endoprosthesis  104  and the covering member, as the pull line coupled to the covering member is retracted, the covering member, as it is removed proximally, can be impeded by its bond with the segment  1212  of slip resistant material  1210  from sliding down what might otherwise comprise a relatively smooth surface of the elongate member, bunching in the process, to eventually become entangled with an end of the endoprosthesis  104 . Thus, the segment  1212  of slip-resistant material  1210  can prevent or reduce entanglement of the covering member with an end of the endoprosthesis  104 . 
     In addition, in a further embodiment, the segment  1212  of slip resistant material  1210  can extend underneath the edge of the endoprosthesis, and the edge of endoprosthesis can be at least partially embedded into the segment  1212  of slip-resistant material  1210 . For example, one or more apices at the edge of the endoprosthesis  104  can be embedded into or nested within the folds of the slip resistant material. Therefore, as the covering member is removed, the member can simply ride over the end of the endoprosthesis  104 , and this can further reduce entanglement between the end of the endoprosthesis  104  and the covering member. Further still, in certain embodiments, the segment  1212  of the slip resistant material  1210  can act to share the load with the endoprosthesis  104 . For example, as the endoprosthesis is maneuvered through the anatomy of a patient (particularly, tortuous anatomy), the segment  1212  of slip resistant material  1210  can permit the endoprosthesis delivery system  1200  to navigate through the anatomy more gently, e.g., by turning around curves and corners more subtly and/or gently. 
     A slip resistant material  1210  can be manufactured, in various embodiments, as shown at  FIGS. 13A-13C . In particular, as shown at  FIG. 13A , a sheet or tape of compliant material  1302  can be wound or rolled about a mandrel  1304 . In various embodiments, compliant material  1302  can comprise a sheet or tape of thin flexible polymeric sheet and optionally, a porous polymer, such as an ePTFE membrane. Now, as shown with reference to  FIG. 13B , the rolled sheet  1306  can be treated, e.g., thermally treated, to prevent it from unrolling and/or adhere it together. Alternatively or in addition thereto, the rolled sheet can be cured with a flexible and optionally an elastomeric adhesive, such as a thermoplastic copolymer of tetrafluoroethylene and perfluoroalkylvinylether as described in U.S. Pat. No. 8,048,440 entitled “Thermoplastic Fluoropolymer-Coated Medical Devices” and U.S. Pat. No. 7,462,675 entitled “Thermoplastic Copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether and Medical Devices Employing the Copolymer,” both of which are incorporated herein by reference in their entirety. The rolled sheet  1306  can finally be scrunched or compressed about its longitudinal axis, as shown at  FIG. 13C , to form the slip resistant material  1210 . In addition, in various embodiments, a slip resistant material  1210  can also be manufactured by helically wrapping a sheet of compliant material  1302  over a mandrel and/or sliding a tube comprising such a material  1302  over an elongate member. 
     Referring now to  FIG. 14 , an endoprosthesis delivery system  1400  is shown. The delivery system  1400  can comprise, in various embodiments, an elongate member  102  is contained within a concentric elongate member  1504  such as an introducer sheath, an endoprosthesis  104 , a covering member  106 , an end cap  1402  adjacent the edge of the endoprosthesis, and optionally, a tapered end cap  1406 . The end cap  1402  prevents the covering member from hanging on the endoprosthesis. In various embodiments, the gap or space, if any, between the end cap  1402  and the edge of the endoprosthesis is less than the diameter of a flexible element. More preferably, the gap between the end cap  1402  and the edge of the endoprosthesis when extended along a curve having a radius commonly encountered in the vasculature is less than the diameter of a flexible element. As such, the end cap  1402  can prevent the endoprosthesis from snagging on the edge of the endoprosthesis. 
     The tapered end cap  1406  increases in diameter in a proximal to distal direction. In various embodiments, as discussed in greater detail below, the tapered end cap  1406  can further comprise one or more raised surface features on the widest or largest diameter portion of the tapered end cap  1406 . These raised surface features can frictionally engage with the inner edge of the concentric elongate member  1504  so that the elongate member  1504  can slide through, but upon advance and contact with the end cap  1406 , an increased pull on the elongate member can allow the tapered end cap  1406  through the concentric elongate member  1504 . For example, the raised surface features can be a deformable material to facilitate passage through concentric elongate member  1504 . 
     In various embodiments, the end cap  1402 , when located on a curved section of vasculature, can optionally bend and elongate along the outer radius. For example, some bending can be facilitated by the end cap  1402  that is constructed of a low durometer tubular piece, as described herein. In other embodiments, the end cap  1402  can comprise a longitudinally compressed polymeric material having creases and folds and abutting the edge of the endoprosthesis and optionally partially deforming thereto, similar to that illustrated in  FIG. 12B . The creases and folds provide some stored length that can be stretched when on a curve. 
     In other embodiments, the end cap  1402  can comprise a small inflatable member that presses against the edge of the endoprosthesis. In other embodiments, the end cap  1402  can comprise an open or closed cell polymeric foam material that presses against the edge of the endoprosthesis, the foam comprising a pre-manufactured component or being formed in place. 
     As described herein, the endoprosthesis  104  can have a distal edge as well as a proximal edge. As shown, the distal edge can abut or be disposed adjacent to the end cap  1402 . Similarly, as shown, the proximal edge can abut or be disposed adjacent to the tapered end cap  1406 . Further, as shown, the diameter of the constrained endoprosthesis  104  can be substantially the same as the diameter of the end cap  1402  and/or the diameter of the distal portion of the tapered member  1406 . 
     With particular regard to the compositions of the end cap  1402  and optionally the tapered end cap  1406 , the components can comprise all or in part, any of a variety of materials. For instance, both components can comprise a mildly or moderately deformable material, i.e., a low durometer material at least on the section closest to the endoprosthesis. For example, the low durometer material can have a durometer between 15 and 70 Shore on the Type A scale. In various embodiments, the end cap  1402  can be constructed so as to more compliant along the axis parallel to the longitudinal axis of the guiding member than across its radial dimension. 
     In various embodiments, the end cap  1402  can be at least partially deformed to the edge profile of the endoprosthesis  104 . This can be accomplished by way of any suitable process and in any manner that is suitable for the purpose. For instance, the proximal edge of the end cap  1402  can be pressed against the distal end of the endoprosthesis  104 , and the deformable properties of the end cap  1402  (or at least the proximal end thereof), can permit the end cap  1402  to at least partially deform to the edge of endoprosthesis  104 . In addition or alternatively, in various embodiments, the end cap  1402  can comprise a concave proximal end, so that the thinnest section of the end cap has the largest diameter. Having a thinner section can facilitate improved deformation to the edge profile. 
     With further regard to the end cap  1402 , at its distal end, the end cap  1402  can optionally be coupled to a catheter olive  108 . The end cap  1402  can be coupled to the olive  108  in any suitable manner. For example, the distal end of the end cap  1402  can fit into a receiving portion formed in the proximal end of the olive  108  and/or bonded within the receiving portion in any suitable fashion, including any number of suitable techniques and/or using any of the materials described herein (e.g., heat bonding, radio frequency bonding, pressure bonding, glue or adhesives, and the like). 
     The covering member  106  can extend over at least a portion of the end cap  1402  and beyond the end cap  1402 . Likewise, in various embodiments, the covering member  106  can extend over at least a portion of the tapered end cap  1406 . 
     During deployment, the covering member  106  can be removed (e.g. unraveled) to uncover or release the endoprosthesis  104  from a constrained diameter. As this process occurs, the end cap  1402  can prevent the covering member  106  from becoming caught, snagged, or entangled with the edge of the endoprosthesis  104 . Rather, the end cap  1402  guides the covering member  106  over the edge of the endoprosthesis  104 . The same process can occur at the proximal end of the endoprosthesis  104 , except that the covering member  106  can follow the tapered end cap  1406  over the proximal end of the endoprosthesis  104 . (Optionally, the end cap  1402  can be a mirror image of the tapered end cap  1406 ; i.e., its tapered end increases in diameter from a distal to proximal direction.) 
     In various embodiments, a post-deployment state can take place after and/or in response to deployment of the endoprosthesis  104 . A post-deployment state is illustrated at  FIG. 15 . As shown, the endoprosthesis  104  has been deployed, exposing the elongate member  102 . The elongate member  102  can be coupled to the end cap  1402  and the tapered end cap  1406  through a channel formed within each component. The tapered end cap  1406  can be slideable along the elongate member  102  and have a distal face that is substantially the same cross-sectional area and shape as the proximal face of the end cap  1402 . 
     To remove the delivery system  1400  from the body lumen of a patient, a physician can withdraw, or cause to be withdrawn, the elongate member  102 . As this occurs, the elongate member  102  can retract proximally through the introducer sheath or other concentric elongate member  1504 . The tapered end cap  1406 , which is slideable along the elongate member  102  and has a distal cross-sectional area substantially equal to or slightly more than the inner diameter of the introducer sheath  1504 , can remain in place against an open end  1502  of the introducer sheath  1504  as the elongate member  102  continues to be withdrawn. Thus, as the elongate member  102  is withdrawn, the proximal face of the end cap  1402  can approach the distal end of the tapered end cap  1406  until contact is made. As contact is made, the end cap  1402 , which is frictionally engaged or otherwise secured to the elongate member  102  can act as a backstop to the tapered end cap  1406 , and, at this juncture, with an additional pull force applied by the operator, the tapered end cap  1406  can be pulled through the open end  1502  of the concentric elongate member  1504 . The tapered end cap  1406  can thus facilitate retraction of the end cap  1402  (which can have a substantially non-tapered proximal face) into the open end  1502  of the outer shaft of the concentric elongate member  1504 . Absent the tapered end cap  1406 , the end cap  1402  might hang on the open end  1502  as an attempt is made to retract the elongate member  102  back through the concentric elongate member  1504 , particularly if the open end  1502  is located on a curve in the vasculature and the elongate member  102  is entering the open end  1502  at an angle relative to the tangential axis at the open end  1502 . 
     With continuing attention to the tapered end cap  1406 , and with brief reference to  FIG. 16 , a channel  1602  is shown formed within the end cap  1406 . This channel can accommodate, as discussed above, the inner shaft  102 . In addition, a concavity or depression  1604  is shown, which can accommodate a pull line for reduced profile and it is contemplated that a plurality of depressions or other features can exist predicated on system needs. 
     With reference to  FIG. 17 , in various embodiments, the endoprosthesis  104  can be loaded with the end cap  1402  and the covering member  106  using a loading funnel  1702 . In particular, the endoprosthesis  104  can be reduced from an unconstrained diameter to a constrained diameter by feeding the endoprosthesis  104  through the loading funnel  1702 . The constrained endoprosthesis  104  can be received, at the reduced diameter portion of the loading funnel  1702 , by the covering member  106 . An inner elongate member  102  can extend substantially coaxially through the covering member  106 , and as the endoprosthetic device  104  is fed through the funnel  1702  into the covering member  106 , the endoprosthesis  104  can further substantially coaxially straddle the inner elongate member  102 . 
     Having received the endoprosthesis  104 , the covering member  106  can be cut or otherwise severed at a particular location. The location can be along a cutline  1704 , and the cutline  1704  can be, as shown, substantially adjacent to, but slightly distal of, the distal end of the endoprosthesis  104 . However, care should be taken not to sever the inner elongate member  102  during this process. Further, although a particular cutline  1704  is shown, in various embodiments, the covering member  106  can be severed at any location along the length of the endoprosthesis  104  and/or at any location(s) distal and/or proximal of the endoprosthesis  104 . Having established the cutline  1704 , any excess covering member  106  can be removed. 
     In the absence of the excised covering member  106 , the end cap  1402  can be coupled to the exposed elongate member. More particularly, the end cap  1402  can, in various embodiments, be mounted on the elongate member and advanced along the elongate member until the end cap  1402  abuts or is compressed against the distal or proximal edge (e.g., the distal apices) of the endoprosthesis  104 . The end cap  1402  can be coupled to the elongate member in any manner suitable for this purpose, such as by way of any of the techniques and/or materials described herein. For example, the end cap  1402  can be frictionally engaged to the elongate member, or be glued or otherwise adhesively fixed to the elongate member. Further, the end cap  1402  can be heat bonded, radio frequency bonded, pressured fitted or bonded, and the like to the elongate member  102 . 
     The tapered end cap  1406  can be similarly coupled to the elongate member  102 . For instance, the covering member  106  can be removed or excised from a portion of the elongate member  102  proximal to the endoprosthesis  104  and the tapered end cap  1406  mounted on the elongate member  102  by way of the channel  1602  formed in the member  106 . The tapered end cap  1406  can be advanced along the elongate member  102  until the tapered end cap  1406  abuts or is compressed against the proximal end of the endoprosthesis  104 . The tapered end cap  1406 , however, may not be coupled to the elongate member  102 , because, as described above, the tapered end cap  1406  can be slideably coupled to the elongate member  102 . 
     In various embodiments, the features and advantages associated with each of the endoprosthesis delivery systems  100 ,  1200 , and  1400 , as described above, can be combined in any desirable manner. For example, although the system  100  is not described above as inclusive of a tapered end cap  1406 , the system  100  can, in various embodiments, include such a tapered end cap  1406 . Similarly, although the compressible material  402  is not described, with respect to system  100  as being folded or ribbed, as disclosed with respect to system  1200 , the compressible material  402  can nevertheless comprise such a texture and/or conformation. 
     A graft comprising any of the grafts and/or stent-grafts described above may be made up of any material which is suitable for use as a graft in the chosen body lumen. A graft may comprise one or a variety of materials. Furthermore, a graft may comprise multiple layers of material, which can be the same material or different material. Although a graft may have several layers of material, the graft may have a layer that is formed into a tube (innermost tube) and an outermost layer that is formed into a tube (outermost tube). In some embodiments, a graft may be fenestrated with a fenestration tool. 
     Many graft materials are known, and in various embodiments, these materials can be used in combination and assembled together to comprise a graft. These materials may be further extruded, coated and/or formed from wrapped films, and/or a combination thereof. Polymeric materials, biodegradable materials, and/or natural materials can be used for specific applications. 
     In various embodiments, a graft may comprise synthetic polymers including nylon, polyacrylamide, polycarbonate, polyformaldehyde, polymethylmethacrylate, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers, polyethylene, polypropylene, polyurethane, polyglycolic acid, polyesters, polyamides, their mixtures, blends, and copolymers. In a variety of embodiments, a graft may be made from a class of polyesters such as polyethylene terephthalate including DACRON® and MYLAR® and polyaramids such as KEVLAR®, polyfluorocarbons such as polytetrafluoroethylene (PTFE) with and without copolymerized hexafluoropropylene (TEFLON® or GORE-TEX®), and porous or nonporous polyurethanes. Further, in a variety of embodiments, a graft may comprise expanded fluorocarbon polymers (especially PTFE) materials. 
     In various embodiments, fluoropolymers, generally referred to herein, may include polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), fluorinated ethylene propylene (FEP), copolymers of tetrafluoroethylene (TFE) and perfluoro (propyl vinyl ether) (PEA), homopolymers of polychlorotrifluoroethylene (PCTFE), and its copolymers with TFE, ethylene-chlorotrifluoroethylene (ECTFE), copolymers of ethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), and polyvinylfluoride (PVF). In various embodiments, a graft can comprise any combination of the materials listed above. Further, in various embodiments, a graft may be substantially impermeable and/or permeable to bodily fluids. A substantially impermeable graft may be made from materials that are substantially impermeable to bodily fluids or can be constructed from permeable materials treated or manufactured to be substantially impermeable to bodily fluids (e.g. by layering different types of materials described above or known in the art). In various embodiments, a stent-graft and/or a side-branch stent-graft, as described above, may be made from any combination of the materials described above, including ePTFE. 
     Any stent, including stent and/or stent members may be generally cylindrical when restrained and/or when unrestrained and may comprise helically arranged undulations having a plurality of helical turns or wraps. In a variety of embodiments, undulations may be aligned so that they are “in-phase” with each other. More specifically, undulations may comprise apices in opposing first and second directions. When these undulations are in-phase, apices in adjacent helical turns are aligned so that apices can be displaced into respective apices of a corresponding undulation in an adjacent helical turn. In certain embodiments, undulations may have a sinusoidal shape, a U shape, a V shape, and/or an ovaloid shape. 
     In various embodiments, a stent may be fabricated from a variety of biocompatible materials including commonly known materials (or combinations of materials) used in the manufacture of implantable medical devices. Such materials may include 316L stainless steel, cobalt-chromium-nickel-molybdenum-iron alloy (“cobalt-chromium”), other cobalt alloys such as L605, tantalum, nitinol, polymers, biodegradable alloys or polymers, or other biocompatible metals. In some embodiments, any stent and/or stent-graft described herein may comprise a balloon expandable stent and/or stent-graft and/or a self-expanding stent and/or stent-graft. Further, in certain embodiments, a stent may comprise a wire wound stent, which may or may not comprise undulations. 
     Example 1—Delivery System Construction 
     In various embodiments, an endoprosthesis delivery system  100  can be manufactured and/or constructed as follows. Generally, an inner shaft  102  wrapping procedure can be followed by an endoprosthesis loading procedure. The inner shaft  102  wrapping procedure can begin with the insertion of a processing mandrel and/or an appropriate inner shaft  102  within a pair of processing chucks coupled to a film wrapping device. The wrapping device can comprise a film payoff head, which can be configured to travel along a length of the inner shaft  102  to wrap a tape or other compressible or compliant material, as described herein, about the shaft  102 . Thus, the inner shaft  102  can be wrapped with a compliant material by the wrapping device. In various embodiments, the film payoff head can make a first pass along an axial length of the shaft  102  and a second pass, in the reverse direction, along the shaft  102  as well. However, the film payoff head can, in other embodiments, make as many or as few passes over the shaft  102  as are desired. 
     One or more flexible elements  110   a - 110   h  can, in addition and as described herein, be coupled to the inner shaft  102 . More particularly, in various embodiments, one or more flexible elements  110   a - 110   h  can be attached or adhered, in any suitable configuration, to the shaft  102  (e.g., over the layer of compliant material deposited, as discussed, above) and/or one or more runs or layers of film or other suitable compliant material layered over each element  110   a - 110   h  to bind the elements  110   a - 110   h  to the shaft  102 . Thus, the inner shaft wrapping procedure can result in a shaft coupled to one or more elements  110   a - 110   h  and/or one or more layers of compliant material. 
     An endoprosthesis  104  can, as part of an endoprosthesis loading procedure, be further loaded on a shaft  102 . The shaft  102  can, in various embodiments, be coupled to the one or more flexible elements  110   a - 110   h  prior to the loading procedure. Therefore, to load the endoprosthesis onto the shaft  102 , an unconstrained endoprosthesis  104  can be inserted over the shaft  102  and fed, in this configuration, into a loading funnel. In addition, as the endoprosthesis  104  enters the loading funnel, each of the flexible elements  1410   a - 110   h  can be threaded, as described herein, through one or more of the apices of the endoprosthesis  104 . The loading funnel can, in this manner, reduce the endoprosthesis  104  to a constrained diameter about the shaft  102 . A covering member  106 , as described herein, can be further positioned at the smaller diameter end of the loading funnel, and the constrained endoprosthesis  104  can be thus fed into the covering member  106  at the output of the funnel. 
     Example 2—Delivery System Construction 
     Continuing, in various embodiments, an endoprosthesis delivery system can be constructed and/or manufactured with an end cap  1402  and/or a tapered end cap  1406  as follows. An endoprosthesis  104  can, as described herein, be loaded through a loading funnel. A process for loading an endoprosthesis through a loading funnel is also generally described by U.S. Pat. No. 6,702,845 to Cully et al., issued Mar. 9, 2004, entitled “Compacted implantable medical devices and method of compacting such devices” which is hereby incorporated by reference in its entirety. The endoprosthesis  104  can be loaded by insertion through the loading funnel on the inner shaft  102 . The distal end of the endoprosthesis can pass through the funnel last, so that the proximal end of the endoprosthesis  104  is received, at the smaller diameter end of the funnel, and as described above, by the covering member  106 . 
     At the distal end of the endoprosthesis  104 , the end cap  1402  can be coupled to the distal edge of the shaft  102 . For example, in various embodiments, the end cap  1402  can comprise any compliant, compressible, elastomeric materials, and the like, such as Shore A 45 durometer PEBAX, and having an inside diameter sized to fit slightly to the distal edge of the shaft by way of compression, interference, or impression between the shaft  102  and the end cap  1402 . The outside diameter of the end cap  1402  can have, in various embodiments, a diameter slightly smaller than a diameter of the loading funnel. Thus, the end cap  1402  can be coupled through the loading funnel to the distal edge of the shaft  102 . The end cap  1402  can be pressed against the distal edge to minimize any gap between the end cap  1402  and the distal edge of the shaft. Further, as discussed above, the endoprosthesis  104  can be advanced through the loading funnel and into a constrained configuration within the covering member  106 . The end cap  1402  can be bonded to the distal edge of the shaft  102  by any suitable means, including, for example, using an adhesive and/or a melt bonding technique. 
     In like fashion, the tapered end cap  1406  can be coupled to the proximal edge of the shaft  202 . For example, the tapered end cap  1406  can comprise any suitable material, including compliant, compressible, elastomeric materials and the like. More particularly, in various embodiments, the end cap  1406  can comprise a Shore A 40 durometer PEBAX. Further, in various embodiments, a radiopaque marker can be located in an end and/or proximate to an edge of the end cap  1406 . The inside diameter of the end cap  1406  can, as discussed herein, be slidably coupled to the shaft  102 , and prior to deployment, the tapered end cap  1406  can be positioned near the distal edge of the shaft  102 . 
     Example 3—Delivery System Construction 
     In various embodiments, a small tubular extrusion of PEBAX can be obtained. The extrusion dimensions can be approximately 1 mm ID×1.2 mm OD, and the material can have a Shore A hardness of 55. A stainless steel mandrel can be inserted into the extrusion lumen and gripped at both ends in a fixture to allow rotation of the extrusion. Further, an ePTFE film, as disclosed by U.S. Pat. No. 5,814,405 to BRANCA, et al., issued Sep. 29, 1998, entitled “Strong, air permeable membranes of polytetrafluoroethylene,” which is hereby incorporated by reference in its entirety, can be wrapped about the extruded tube and attached to the extrusion through thermal treatment, for example using a Weller soldering iron. A strip of film (e.g., in various embodiments, a strip of approximately 80 mm in width) can be longitudinally wrapped about the extrusion parallel to the central axis of the extrusion, using minimal tension, by rotating the extrusion. Where such a strip is used, the 80 mm width can be approximately 20 mm longer than the length of the medical implant (e.g., the endoprosthesis  104 ) being delivered; therefore, once the implant is centrally loaded on this compressible member, there will be approximately 10 mm of compressible material exposed at either end of the implant. In various embodiments, differing numbers of film layers can be applied. For instance, in certain embodiments, approximately 30 layers of film can be applied, thus building up a lofty, compressible zone over which to load an endoprosthesis  104 . In various embodiments, the compressible member can be formed in place using an appropriate mold and moldable material such as an injectable foam. 
     The film strip can then be cut and its loose end attached to an underlying layer, again through the use of localized heat. This compressible zone can then be used as is to load a stent, stent graft, or other endoprosthesis  104 . During the loading process, the endoprosthesis  104  can be radially compressed into its delivery dimensions. During compression, the device compresses into the loft of the compressible member, which increases device to catheter retention quality, which ultimately improves accuracy of deployment in the clinical setting. The constraining device can also receive benefit since it too can compress into the compressible material which extends approximately 10 mm at each end of the implant. This can assist in stabilizing it during subsequent delivery and deployment. Optionally, and to add increased benefit, the compressible material can have a layer of silicone (available from NuSil, Carpinteria, Calif. as product #MED 1137) applied to it. Application can be accomplished by dipping, spraying or brushing or the like. Upon curing, this thin, tacky layer adds additional utility in that it can assist in adhering the layers of the ePTFE film together and can provide a tacky surface to which both endoprosthesis  104  and covering member  106  can temporarily grip during the delivery and deployment sequence. 
     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.