Patent Publication Number: US-2020281750-A1

Title: Sleeves for expandable medical devices

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 15/678,806, filed Aug. 16, 2017, which claims the benefit of U.S. Provisional Application No. 62/379,001, filed Aug. 24, 2016, both of which are herein incorporated by reference in their entireties. 
    
    
     FIELD 
     The present disclosure relates generally to the transcatheter delivery and remote deployment of implantable medical devices. 
     BACKGROUND 
     Endoluminal devices used to treat a treatment area of the vasculature of a patient are typically delivered via a delivery system including a catheter. Such endoluminal devices may comprise, for example, expandable implants. Expandable endoluminal devices can be comprised of a graft or a stent component with or without a graft covering over the stent interstices. They can be designed to expand when a restraint, such as a sleeve is removed or be balloon-expanded from a delivery diameter to a pre-determined functional diameter. 
     SUMMARY OF THE DISCLOSURE 
     This disclosure is generally directed to flexible sleeves formed from a single sheet of material including a first lumen configured to receive a constrained implantable medical device, such as an endoprosthesis, and a second lumen configured to receive at least one control feature, such as a deployment feature and/or a steering member. 
     In one variation, an endoprosthesis constraining sleeve includes a single sheet of material forming at least two folds, and a common bond line constraining the single sheet of material to maintain the at least two folds and to form at least two discrete lumens. A first lumen of the at least two lumens is configured to receive a constrained endoprosthesis therein. A second lumen of the at least two lumens is configured to receive a control feature therethrough. 
     In some examples, the control feature includes one or more of a group consisting of: a deployment feature, and a steering member. 
     In the same or different examples, the common bond line includes at least one of: a thermal bond, and a stitch line. 
     In the same or different examples, the first lumen is formed from a single layer of the single sheet of material. In some of such examples, the second lumen is formed from two layers of the single sheet of material. In other of such examples, the second lumen is formed from a single layer of the single sheet of material. 
     In the same or different examples, the single sheet of material includes a first side and a second side, and an interior surface of the first lumen is formed by the first side of the single sheet of material, and an interior surface of the second lumen is formed by the first side of the single sheet of material. 
     In the same or different examples, the single sheet of material includes a first side and a second side, an interior surface of the first lumen is formed by the first side of the single sheet of material, and an interior surface of the second lumen is formed by the second side of the single sheet of material. In some of such examples, the second lumen is formed from two layers of the single sheet of material. In some of such examples, the second lumen is within the first lumen. In some of such examples, a first fold of the at least two bends the first side of the single sheet of material back on itself towards the common bond line to form the first lumen, and a second fold of the at least two bends the second side of the single sheet of material back on itself towards the common bond line to form the second lumen. 
     In the same or different examples, the at least two folds includes at least three folds, the at least two discrete lumens includes at least three discrete lumens, and the common bond line constrains the single sheet of material to maintain the at least three folds and to form the at least three discrete lumens. 
     In the same or different examples, the common bond line is generally parallel with a longitudinal axis of the constrained endoprosthesis. 
     In the same or different examples, the first lumen is configured to constrain the endoprosthesis to an intermediate configuration. 
     In the same or different examples, the single sheet of material includes an expanded polytetrafluoroethylene (ePTFE) base layer. In some of such examples, the single sheet of material includes a thermoplastic coating on one side of the ePTFE base layer. 
     In the same or different examples, the single sheet of material includes fluorinated ethylene propylene (FEP) layer. 
     In the same or different examples, the endoprosthesis is a stent graft. 
     In another variation, an endoprosthesis delivery system includes: a primary sleeve, a secondary sleeve within the primary sleeve, an expandable endoprosthesis within the primary sleeve and the secondary sleeve, the primary sleeve constraining the expandable endoprosthesis to a collapsed configuration, and a control feature. The secondary sleeve is formed from a single sheet of material forming at least two folds, the secondary sleeve including a common bond line constraining the single sheet of material to maintain the at least two folds and to form at least two discrete lumens. The expandable endoprosthesis is constrained within a first lumen of the at least two lumens. The control feature extends within a second lumen of the at least two lumens. 
     In some examples, the first lumen is configured to constrain the endoprosthesis to an intermediate configuration following the release of the expandable endoprosthesis from the primary sleeve, the intermediate configuration being larger than the collapsed configuration and smaller than a fully deployed configuration. 
     In the same or different examples, control feature is a deployment feature configured to release the expandable endoprosthesis from the primary sleeve. 
     In the same or different examples, the endoprosthesis delivery system further includes a secondary deployment feature configured to release the expandable endoprosthesis from the first lumen of secondary sleeve to allow expansion from the intermediate configuration to the fully deployed configuration. In some of such examples, the common bond line includes a stitch line, and the secondary deployment feature is a deployment line configured to release the stitch line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate examples of the disclosure, and together with the description serve to explain the principles of the disclosure, wherein: 
         FIG. 1  illustrates a side view of a delivery system for an expandable implant; 
         FIGS. 2A and 2B  illustrate perspective views of delivery systems for expandable implants, the delivery systems including constraining sleeves with at least two lumens; 
         FIGS. 3A-3C  illustrate example techniques for forming an endoprosthesis constraining sleeve including two lumens from a single sheet of material with two folds and a common bond line; 
         FIGS. 4A-4C  illustrate additional example techniques for forming an endoprosthesis constraining sleeve including two lumens from a single sheet of material with two folds and a common bond line; 
         FIGS. 5A-5F  illustrate further example techniques for forming an endoprosthesis constraining sleeve including two lumens from a single sheet of material with two folds and a common bond line; and 
         FIGS. 6A-6E  illustrate example techniques for forming an endoprosthesis constraining sleeve including three lumens from a single sheet of material with three folds and a common bond line. 
     
    
    
     DETAILED DESCRIPTION 
     Various examples of the present disclosure are directed to flexible sleeves including a first lumen configured to receive a constrained endoprosthesis therein, and a second lumen configured to receive a delivery system component, such as at least one control feature (e.g., a deployment feature and/or a steering member). 
     Providing a separate lumen for a delivery system component may improve the reliability of the system (e.g., by limiting contact between components of a delivery system including the sleeve), may reduce undesirable contact between a delivery system component and a vessel wall thereby reducing a risk of trauma to the vessel (e.g., by limiting contact between components of a delivery, such as a steering wire, and the vessel wall), and may simplify the manufacture of such delivery systems, and achieve additional or alternative advantages. 
     In some of such examples, one or more flexible sleeves may further be configured to releasably constrain an expandable implant, such as an expandable endoluminal stent graft, toward a dimension suitable for endoluminal delivery of the implant to a treatment site, such as a vascular member in a patient&#39;s body. The one or more flexible sleeves may further constrain the implant to an intermediate outer peripheral dimension that is larger than the dimension suitable for endoluminal delivery but smaller than an unconstrained or fully deployed outer peripheral dimension. Controlled expansion to such an intermediate outer peripheral dimension may facilitate selective axial and/or rotational positioning or other manipulation of the implant at the treatment site prior to full deployment and expansion of the implant. 
     Example endoprosthesis constraining sleeves including at least two lumens formed from a single sheet of material are described with respect to  FIGS. 3A-6E .  FIGS. 1-2B  illustrate perspective views of delivery systems having constraining sleeves such as those described in further detail with respect to  FIGS. 3A-6E . 
     With initial reference to  FIG. 1 , a delivery system  100  in accordance with the present disclosure comprises an expandable implant  106 . Expandable implant  106  can comprise any endoluminal device suitable for delivery to the treatment area of a vasculature. Such devices may include, for example, stents, grafts, and stent grafts. Thus, expandable implant  106  can include one or more stent components with one or more associated graft members disposed over and/or under the stent, which can dilate from a delivery diameter, through a range of larger intermediary diameters, and toward a maximal, pre-determined functional diameter. 
     In various examples, expandable implant  106  comprises one or more stent components made of nitinol and a graft member made of ePTFE. However, and as discussed below, any suitable combination of stent component(s) and graft member(s) is within the scope of the present disclosure. 
     Stent components can have various configurations such as, for example, rings, cut tubes, wound wires (or ribbons) or flat patterned sheets rolled into a tubular form. Stent components can be formed from metallic, polymeric or natural materials and can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol and biologically derived materials such as bovine arteries/veins, pericardium and collagen. Stent components can also comprise bioresorbable materials such as poly(amino acids), poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) and poly(orthoesters). Any expandable stent component configuration which can be delivered by a catheter is in accordance with the present disclosure. 
     Moreover, potential materials for graft members include, for example, expanded polytetrafluoroethylene (ePTFE), polyester, polyurethane, fluoropolymers, such as perfouorelastomers and the like, polytetrafluoroethylene, silicones, urethanes, ultra-high molecular weight polyethylene, aramid fibers, and combinations thereof. Other examples 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.). The graft member may include a bioactive agent. In one example, an ePTFE graft includes a carbon component along a blood contacting surface thereof. Any graft member that can be delivered by a catheter is in accordance with the present disclosure. 
     In various examples, a stent component and/or graft member can comprise a therapeutic coating. In these examples, the interior and/or exterior of the stent component and/or graft member can be coated with, for example, a CD34 antigen. Additionally, any number of drugs or therapeutic agents can be used to coat the graft member, including, for example heparin, sirolimus, paclitaxel, everolimus, ABT-578, mycophenolic acid, tacrolimus, estradiol, oxygen free radical scavenger, biolimus A9, anti-CD34 antibodies, PDGF receptor blockers, MMP-1 receptor blockers, VEGF, G-CSF, HMG-CoA reductase inhibitors, stimulators of iNOS and eNOS, ACE inhibitors, ARBs, doxycycline, and thalidomide, among others. 
     In various examples, expandable implant  106  can comprise a radially collapsed configuration suitable for delivery to the treatment area of the vasculature of a patient. Expandable implant  106  can be constrained toward a radially collapsed configuration and releasably mounted onto a delivery device such as catheter shaft  102 . The diameter of the expandable implant  106  in the collapsed configuration is small enough for the implant to be delivered through the vasculature to the treatment area. In various examples, the diameter of the collapsed configuration is small enough to minimize the crossing profile of delivery system  100  and reduce or prevent tissue damage to the patient. In the collapsed configuration, the expandable implant  106  can be guided by catheter shaft  102  through the vasculature. 
     In various examples, expandable implant  106  can comprise a radially expanded configuration suitable for implanting the device in the treatment area of a patient&#39;s vasculature. In the expanded configuration, the diameter of expandable implant  106  can be approximately the same as the vessel to be repaired. In other examples, the diameter of expandable implant  106  in the expanded configuration can be slightly larger than the vessel to be treated to provide a traction fit within the vessel. 
     In various examples, expandable implant  106  can comprise a self-expandable device, such as a self-expandable stent graft. Such devices dilate from a radially collapsed configuration to a radially expanded configuration when unconstrained. In other examples, expandable implant  106  can comprise a device that is expanded with the assistance of a secondary device such as, for example, a balloon. In yet other examples, delivery system  100  can comprise a plurality of expandable implants  106 . The use of a delivery system with any number of expandable implants is within the scope of the present disclosure. 
     Various medical devices in accordance with the disclosure comprise a sleeve or multiple sleeves. The sleeve or sleeves may constrain an expandable implant device in a collapsed configuration for endoluminal delivery of the implant to a treatment portion of the vasculature of a patient. For the purposes of the disclosure, the term “constrain” may mean (i) to limit the expansion, either through self-expansion or assisted by a device, of the diameter of an expandable implant or (ii) to cover or surround but not otherwise constrain an expandable implant (e.g., for storage or biocompatibility reasons and/or to provide protection to the expandable implant and/or the vasculature). Delivery system  100 , for example, comprises a sleeve  104  which surrounds and constrains expandable implant  106  toward a reduced diameter or collapsed configuration. 
     After deployment, the sleeve or sleeves can be removed in order to allow the expandable implant to expand toward a functional diameter and achieve a desired therapeutic outcome. Alternatively, the sleeve or sleeves can remain coupled to the implant or otherwise implanted while not interfering with the expandable implant. 
     In various examples, an expandable implant is constrained by a single sleeve which circumferentially surrounds the expandable implant. For example, with reference to  FIG. 2B , delivery system  200  comprises a sleeve  204 . In various examples, sleeve  204  circumferentially surrounds expandable implant  206  and constrains it toward a collapsed configuration, in which the diameter is less than the diameter of an unconstrained or otherwise deployed implant. For example, sleeve  204  may constrain expandable implant  206  toward a collapsed configuration for delivery within the vasculature. In this example, expandable implant  206  represents an expandable endoprosthesis, such as a stent, a graft, or a stent graft. 
     In other examples, an expandable implant is constrained by a plurality of sleeves which circumferentially surround the expandable implant, which allow the expandable implant to be deployed and held at intermediate configurations larger than the collapsed configuration and smaller than the deployed configuration. The plurality of sleeves can comprise at least two sleeves which circumferentially surround each other. 
     In various examples, sleeves can be tubular and serve to constrain an expandable implant. In such configurations, sleeves are formed from a sheet of one or more materials wrapped or folded about the expandable implant. While the illustrative examples herein are described as comprising one or more tubular sleeves, sleeves of any non-tubular shape that corresponds to an underlying expandable implant or that are otherwise appropriately shaped for a given application are also within the scope of the present disclosure. 
     In various examples, sleeves are formed by wrapping or folding the sheet of material(s) such that two parallel edges of the sheet are substantially aligned. Said alignment may or may not be parallel to or coaxial with the catheter shaft of a delivery system. In various examples, a single coupling member can be used to constrain the diameter of two or more sleeve lumens, e.g., as illustrated in further detail with respect to  FIGS. 3A-6E . 
     In various examples, the edges of the sheet of material(s) do not contact each other. In other examples, the edges of the sheet of material(s) do contact each other and are coupled with a coupling member (as described below), a thermal bond, an adhesive, or the like. In various other examples, the edges of the sheet of material(s) are aligned so that the edges of the same side of the sheet or sheets (e.g., the front or back of the sheet) are in contact with each other. In still other examples, the edges of opposite sides of the sheet of material(s) are in contact with each other, such that the edges overlap each other, such that a portion of one side of the sheet is in contact with a portion of the other side. Said another way, the front of the sheet may overlap the rear of the sheet, or vice versa. 
     The sheet of material(s) used to form the sleeve(s) can comprise a series of openings, such that the openings extend from one edge of the sheet to the other. In such configurations, a coupling member can be woven or stitched through the series of openings in the sheet of material(s), securing each of the two edges together and forming a tube. For example, in  FIG. 1 , coupling member  124  secures the edges of sleeve  104  such that sleeve  104  maintains expandable implant  106  toward a reduced diameter or outer peripheral dimension suitable for endoluminal delivery. 
     In various examples, the coupling member can comprise a woven fiber. In other examples, the coupling member can comprise a monofilament fiber. Any type of string, cord, thread, fiber, or wire which is capable of maintaining a sleeve in a tubular shape is within the scope of the present disclosure. 
     Once a suitable expandable implant is in a collapsed configuration, the expandable implant can be deployed within the vasculature of a patient. An expandable implant in a collapsed configuration can be introduced to a vasculature and directed by a delivery system to a treatment area of the vasculature. 
     When the expandable implant is in position within the vasculature, the coupling member or members can be disengaged from the sleeve or sleeves from outside of the body of the patient, which allows the sleeve(s) to open and the expandable implant to expand. The coupling member or members can be disengaged from the sleeve or sleeves by a mechanical mechanism operated from outside of the body of the patient. For example, the member or members can be disengaged by applying sufficient tension to the member or members. In another example, a translatable element can be attached to the coupling member or members outside of the body. Displacement of the translatable elements, such as rotation of a dial or rotational member or translation of a handle or knob, may provide sufficient tension to displace and disengage the coupling member or members. 
     In various examples, disengaging a single coupling member which closes a single sleeve of a set of concentric sleeves allows the expandable device to be expanded toward a larger diameter or outer peripheral dimension. A primary sleeve may constrain the expandable device in a fully-collapsed configuration whereas a secondary sleeve may constrain the expandable device in an intermediate configuration once the expandable device is released from the primary sleeve. 
     In the intermediate configuration, the diameter of the expandable implant is constrained in a diameter smaller than the expanded configuration and larger than the collapsed configuration. For example, the diameter of the expandable device in the intermediate configuration can be about 70% of the diameter of the expandable device in the expanded configuration. However, any diameter of the intermediate configuration which is less than the diameter of the expanded configuration and larger than the collapsed configuration is contemplated by this disclosure. 
     In such examples, the expandable implant can be expanded from the collapsed configuration toward the intermediate configuration once the implant has been delivered near the treatment area of the vasculature of a patient. The intermediate configuration may, among other things, assist in properly orienting and locating the expandable implant within the treatment area of the vasculature. In addition, sleeves including at least two lumens that are as large or larger than the expanded configuration are also contemplated by this disclosure. Such sleeves may allow full deployment of an endoprosthesis within one lumen with one or more control features being located within one or more other lumens. Such control features are separated from the endoprosthesis even under full expansion, thereby still providing advantages of having at least two lumens as described in this disclosure. 
     In various examples, an expandable implant can be concentrically surrounded by two sleeves having different diameters. In such configurations, a primary sleeve constrains the expandable implant toward the collapsed configuration. Once the collapsed configuration sleeve is opened, a secondary sleeve constrains the expandable implant toward the intermediate configuration. As discussed above, the expandable implant can be self-expanding, or the implant can be expanded by a device, such as a balloon. 
     For example, with reference to  FIG. 2A , a delivery system  200  comprises an expandable implant  206 , sleeve  208 , and secondary sleeve  204 . Secondary sleeve  204  constrains expandable implant  206  toward an intermediate configuration. Secondary sleeve  204  is held in position around expandable implant  206  by secondary coupling member  224 . 
     Delivery system  200  further comprises a primary sleeve  208 , which constrains expandable implant  206  toward a collapsed configuration for delivery to the vasculature of a patient. Primary sleeve  208  is held in position around expandable implant  206  by primary coupling member  234 . Coupling member  234  represents a deployment feature as pulling on a proximal end of coupling member  234  may release coupling member  234  from sleeve  208  to deploy expandable implant  206 . For example, during an implantation procedure, once expandable implant  206  is sufficiently close to the treatment area of the vasculature, primary coupling member  234  is disengaged from primary sleeve  208 , which releases primary sleeve  208  and allows expanded implant  206  to expand toward a larger diameter. 
     With reference to  FIG. 2B , after primary sleeve  208  has been released, first lumen  203  of secondary sleeve  204  constrains the expandable implant  206  toward the intermediate configuration. In the intermediate configuration, expandable implant  206  can be oriented and adjusted (e.g., by bending and torsional rotation) to a desired location within the treatment area of the vasculature. 
     Although a number of specific configurations of constraining members (for example, primary and secondary members) and sleeves (for example, primary and secondary sleeves) have been discussed, the use of any number and/or configuration of constraining members and any number of sleeves is within the scope of the present disclosure. 
     In some particular examples, expandable implant  206  may be an expandable endoprosthesis used to treat abdominal aortic aneurisms such that expandable implant  206  is configured to seal-off the weakened wall of the aorta. Delivery to the treatment site may occur via the iliac or femoral arteries in the thigh. The bends and angles of such vasculatures may cause difficulties that are mitigated by the design of secondary sleeve  204 . 
     For example, in the illustrated example, secondary sleeve  204  further includes a second lumen  205 , which is configured to receive at least one delivery system component, such as at least one control feature (e.g., a deployment feature and/or a steering member). Examples sleeves with at least two lumens are illustrated in further detail with respect to  FIGS. 3A-6E . In different examples, the control feature within a second lumen may be a steering member, such as steering line  220  or a guidewire, a deployment feature, such as coupling member  224  and/or coupling member  234 , or another control feature. Providing a separate lumen for a control feature may improve the reliability of the control feature by limiting contact with a constrained endoprosthesis or other components of a delivery system including the sleeve and/or simplify the manufacture of a delivery system including the sleeve by separating the control feature from the constrained endoprosthesis and, optionally from other components of the delivery system, such as a stitch line of the sleeve. 
     Secondary sleeve  204  is formed from a single sheet of material forming at least two folds, and includes a common bond line constraining the single sheet of material to maintain the at least two folds and to form at least two discrete lumens, including first lumen  203  and second lumen  205 . In the disclosed example, coupling member  224  forms a stitch line  226 , which represents the common bond line. The distal end coupling member  224  represents a deployment line  228  configured to release stitch line  226 . In other examples, the common bond line may represent a thermal bond, an adhesive bond or other bond. 
     In some particular examples, the single sheet of material forming secondary sleeve  204  includes an ePTFE base layer. In the same or different examples, the single sheet of material forming secondary sleeve  204  may include a thermoplastic coating on one or both sides of the base layer, such as a fluorinated ethylene propylene (FEP) layer. 
     In various examples, the delivery system further comprises a steering line. In such configurations, tension can be applied to the steering line to displace the steering line and bend the expandable implant. Bending the expandable implant may, among other things, assist in travelling through curved or tortuous regions of vasculature. Bending the expandable implant may also allow the implant to conform to curvatures in the vasculature of a patient, such as curvatures occurring during implantation to correct an abdominal aortic aneurism. 
     With reference to  FIGS. 2A-2B , steering line  220 , an example steering member, passes from the outside of the body of a patient, through catheter shaft  202 , through second lumen  205  of secondary sleeve  204 , and is releasably coupled to expandable implant  206 . In such configurations, steering line  220  can be threaded through expandable implant  206  such that tension applied to steering line  220  from outside of the body of the patient causes expandable implant  206  to bend in a desired manner. For example, a suitable steering line is disclosed by U.S. Pat. No. 9,375,308, titled, “EXTERNAL STEERABLE FIBER FOR USE IN ENDOLUMINAL DEPLOYMENT OF EXPANDABLE DEVICES,” the entire contents of which are incorporated by reference herein. 
     In various examples, steering line  220  can comprise metallic, polymeric or natural materials and can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol. Elongated members or lock wires can also be formed from 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.). 
     In various examples, expandable implant  206  may comprise a fenestratable portion. In such configurations, expandable implant  206  may include a frangible material which may be fenestrated by an endoluminal tool after expandable implant  206  has been partially or completely implanted in the vasculature of a patient. Once fenestrated, fenestratable portion may be used, for example, to install branching stent grafts to expandable implant  206 . Side branch fenestrations allow for branching devices, such as branching stent grafts, to be connected to and in with communication expandable implant  206 . Such fenestrations and branching stent grafts may facilitate conforming expandable implant  206  and additional branching stent grafts to the anatomy of a patient, such as iliac arteries and associated vascular branches. 
     Example endoprosthesis constraining sleeves including at least two lumens formed from a single sheet of material are described with respect to  FIGS. 3A-6E . These example endoprosthesis constraining sleeves are each suitable for use as secondary sleeve  204 , as are numerous other variations not specifically illustrated. 
       FIGS. 3A-3C  illustrate techniques for forming endoprosthesis constraining sleeve  304 , which includes two lumens  303 ,  305 . Endoprosthesis constraining sleeve  304  is formed from a single sheet of material  300  ( FIG. 3A ) with two folds  342 ,  344  and a common bond line  326 . Endoprosthesis constraining sleeve  304  may be used as secondary sleeve  204  within delivery system  200 , as the only constraining sleeve within another delivery system, or with any medical assembly in which it is useful to provide at least two adjacent lumens. 
     The single sheet of material  300  includes a first side  301  and a second side  302 . In some examples, single sheet of material  300  may include an exposed ePTFE layer on second side  302  with an exposed thermoplastic layer, such as an FEP layer on first side  301 . 
     To form endoprosthesis constraining sleeve  304  from the single sheet of material  300 , fold  342  is made to form lumen  303 , and fold  344  is made to form lumen  305 . Folds  342 ,  344  each bends side  301  back on itself towards common bond line  326  to form lumens  303 ,  305 . 
     Lumen  303  may be configured to receive a constrained implantable medical device, such as an endoprosthesis, and lumen  305  may be configured to receive at least one control feature, such as a deployment feature and/or a steering member. Lumen  305  is optionally shorted than lumen  303 . After folding, common bond line  326 , which may, for example, represent a stitch line or a thermal bond, maintains folds  342 ,  344  to form lumens  303 ,  305 . Common bond line  326  may be generally parallel with a longitudinal axis of an endoprosthesis constrained within one of lumens  303 ,  305 . 
       FIG. 3B  illustrates a top view of endoprosthesis constraining sleeve  304 , and  FIG. 3C  illustrates a side view of endoprosthesis constraining sleeve  304 . As best illustrated in  FIG. 3C , lumens  303 ,  305  are each formed from a single layer of the single sheet of material  300 . The interior surfaces of lumens  303 ,  305  are each formed from side  301  of the single sheet of material  300 . In other examples, the orientation of the single sheet of material  300  could be reversed such that interior surfaces of lumens  303 ,  305  are each formed from side  302  of the single sheet of material  300 . 
       FIGS. 4A-4C  illustrate techniques for forming endoprosthesis constraining sleeve  404 , which includes two lumens  403 ,  405 . Endoprosthesis constraining sleeve  404  is formed from a single sheet of material  400  ( FIG. 4A ) with two folds  442 ,  444  and a common bond line  426 . Endoprosthesis constraining sleeve  404  may be used as secondary sleeve  204  within delivery system  200 , as the only constraining sleeve within another delivery system, or with any medical assembly in which it is useful to provide at least two adjacent lumens. 
     The single sheet of material  400  includes a first side  401  and a second side  402 . In some examples, single sheet of material  400  may include an exposed ePTFE layer on second side  402  with an exposed thermoplastic layer, such as an FEP layer on first side  401 . 
     To form endoprosthesis constraining sleeve  404  from the single sheet of material  400 , fold  442  is made to form lumen  403 , and fold  444  is made to form lumen  405 . Fold  442  bends side  402  back on itself towards common bond line  426  to form lumen  403 , whereas fold  444  bends side  401  back on itself towards common bond line  426  to form lumen  405 . 
     Lumen  403  may be configured to receive a constrained implantable medical device, such as an endoprosthesis, and lumen  405  may be configured to receive at least one control feature, such as a deployment feature and/or a steering member. Lumen  405  is optionally shorted than lumen  403 . After folding, common bond line  426 , which may, for example, represent a stitch line or a thermal bond, maintains folds  442 ,  444  to form lumens  403 ,  405 . Common bond line  426  may be generally parallel with a longitudinal axis of an endoprosthesis constrained within one of lumens  403 ,  405 . 
       FIG. 4B  illustrates a top view of endoprosthesis constraining sleeve  404 , and  FIG. 4C  illustrates a side view of endoprosthesis constraining sleeve  404 . As best illustrated in  FIG. 4C , lumens  403 ,  405  are each formed from a single layer of the single sheet of material  400 . The interior surfaces of lumen  403  are formed from side  402  of the single sheet of material  400 , whereas the interior surfaces of lumen  403  are formed from side  401  of the single sheet of material  400 . In other examples, the orientation of the single sheet of material  400  could be reversed such interior surfaces of lumen  403  are formed from side  401  of the single sheet of material  400 , and the interior surfaces of lumen  403  are formed from side  402  of the single sheet of material  400 . 
       FIGS. 5A-5F  illustrate techniques for forming endoprosthesis constraining sleeve  504 , which includes two lumens  503 ,  505 . Endoprosthesis constraining sleeve  504  is formed from a single sheet of material  500  ( FIG. 5A ) with two folds  542 ,  544  and a common bond line  526 . Endoprosthesis constraining sleeve  504  may be used as secondary sleeve  204  within delivery system  200 , as the only constraining sleeve within another delivery system, or with any medical assembly in which it is useful to provide at least two adjacent lumens. 
     The single sheet of material  500  includes a first side  501  and a second side  502 . In some examples, the single sheet of material  500  may include an exposed ePTFE layer on second side  502  with an exposed thermoplastic layer, such as an FEP layer on first side  501 . 
     As shown in  FIGS. 5B and 5C , to form endoprosthesis constraining sleeve  504 , fold  542  bends side  501  back on itself to fold the single sheet of material  500  about in half. Then, as shown in  FIGS. 5D and 5E , fold  544  bends side  502  back on itself to redouble a portion of the folded single sheet of material  500 . Common bond line  526  maintains both of folds  542  and  544  in place to form lumens  503 ,  505 . 
     Lumen  503  may be configured to receive a constrained implantable medical device, such as an endoprosthesis, and lumen  505  may be configured to receive at least one control feature, such as a deployment feature and/or a steering member. Lumen  505  is optionally shorted than lumen  503 . Common bond line  526 , which may, for example, represent a stitch line or a thermal bond, may be generally parallel with a longitudinal axis of an endoprosthesis constrained within one of lumens  503 ,  505 . 
       FIG. 5E  illustrates a top view of endoprosthesis constraining sleeve  504 , and  FIG. 5F  illustrates a side view of endoprosthesis constraining sleeve  504 . As best illustrated in  FIG. 5F , lumen  503  is formed from a single layer of the single sheet of material  500 , whereas lumen  505  is formed from a double layer of the single sheet of material  500 . The interior surfaces of lumen  503  are formed from side  501  of the single sheet of material  500 , whereas the interior surfaces of lumen  503  are formed from side  502  of the single sheet of material  500 . In other examples, the orientation of the single sheet of material  500  could be reversed such interior surfaces of lumen  503  are formed from side  502  of the single sheet of material  500 , and the interior surfaces of lumen  503  are formed from side  501  of the single sheet of material  500 . 
       FIGS. 6A-6E  illustrate techniques for forming endoprosthesis constraining sleeve  604 , which includes three lumens  603 ,  605 ,  607 . Endoprosthesis constraining sleeve  604  is formed from a single sheet of material  600  ( FIG. 6A ) with three folds  642 ,  644 ,  646  and a common bond line  626 . Endoprosthesis constraining sleeve  604  may be used as secondary sleeve  204  within delivery system  200 , as the only constraining sleeve within another delivery system, or with any medical assembly in which it is useful to provide at least two adjacent lumens. 
     The single sheet of material  600  includes a first side  601  and a second side  602 . In some examples, the single sheet of material  600  may include an exposed ePTFE layer on second side  602  with an exposed thermoplastic layer, such as an FEP layer on first side  601 . 
     As shown in  FIGS. 6B and 6C , to form endoprosthesis constraining sleeve  604 , fold  642  bends a portion of side  601  back on itself. Then, as shown in  FIGS. 6C and 6D , fold  644  bends side  602  back on itself to provide a three layered portion of the folded single sheet of material  600 . Then fold  646  bends side  601  back on itself to cover the three layered portion and provide a four layered portion of the folded single sheet of material  600 . Common bond line  626  maintains each of folds  642 ,  644 ,  646  in place to form lumens  603 ,  605 ,  607 . 
     Lumen  603  may be configured to receive a constrained implantable medical device, such as an endoprosthesis, and lumen  605  may be configured to receive at least one control feature, such as a deployment feature and/or a steering member. In some examples, lumen  607  may not be used, but in other examples lumen  607  may also be configured to receive at least one control feature, such as a deployment feature and/or a steering member. Common bond line  626 , which may, for example, represent a stitch line or a thermal bond, may be generally parallel with a longitudinal axis of an endoprosthesis constrained within one of lumens  603 ,  605 ,  607 . 
       FIG. 6D  illustrates a top view of endoprosthesis constraining sleeve  604 , and  FIG. 6E  illustrates a side view of endoprosthesis constraining sleeve  604 . As best illustrated in  FIG. 6E , lumens  603  and  607  are each formed from a single layer of the single sheet of material  600 , whereas lumen  605  is within lumen  603 , and thus, formed from a double layer of the single sheet of material  600 . The interior surfaces of lumens  603  and  607  are formed from side  601  of the single sheet of material  600 , whereas the interior surfaces of lumen  603  are formed from side  602  of the single sheet of material  600 . In other examples, the orientation of the single sheet of material  600  could be reversed such interior surfaces of lumens  603  and  607  are formed from side  602  of the single sheet of material  600 , and the interior surfaces of lumen  603  are formed from side  601  of the single sheet of material  600 . 
     Various modifications may be made to the disclosed examples within the spirit of this disclosure, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations within the principles of the disclosure, to the full extent indicated by the broad, general meaning of the terms in which the appended claims are expressed. For example, while a variety of example configurations are provided, numerous additional configurations for endoprosthesis constraining sleeves including two lumens from a single sheet of material can readily be made within the spirit of this disclosure. To the extent that these various modifications and configurations do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.