Patent Publication Number: US-2022218503-A1

Title: Locking assembly for coupling guidewire to delivery system

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     This application is a national phase filing of PCT Application No. PCT/US2016/040197, filed Jun. 29, 2016, which claims the benefit of U.S. Provisional Application No. 62/187,103, filed Jun. 30, 2015, which is hereby incorporated by reference in its entirety herein. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to devices and methods for reversibly coupling a guidewire or other elongate structure to a delivery system. 
     Description of the Related Art 
     Some surgical procedures require multiple guidewires, for example to facilitate delivery of an implant to a branched vessel or maintain access in a branched vessel. During these procedures, an implant can be delivered via a delivery system through a first branch vessel (e.g., ipsilateral iliac artery) and access can be provided through a second branch vessel (e.g., contralateral iliac artery) using a catheter, guidewire, or otherwise. However, existing techniques for providing access to the branch vessel involve many steps and may increase the size of the delivery system, thus making the procedure more difficult to perform. 
     SUMMARY 
     Certain embodiments described herein are directed to systems, methods and apparatuses for treating endovascular aneurysms or other endovascular defects. However, it will be appreciated that the systems, methods and apparatuses may have application to other fields. In some embodiments, the defects being treated may include, but are not limited to, abdominal aortic aneurysms, subclavian aneurysms, and thoracic aortic aneurysms, to name a few. 
     As mentioned above, certain surgical procedures, such as those for treating aortic aneurysms may involve the use of multiple guidewires to maintain access through multiple vessels. However, managing multiple guidewires can be difficult, for example because a contralateral guidewire may be inadvertently withdrawn when a sheath or other tubular structure is withdrawn over the contralateral guidewire. Existing systems may utilize a hollow guidewire or other tubular structure to couple a contralateral portion of the delivery system to an ipsilateral portion of the delivery system or to facilitate advancement of a contralateral guidewire to the target vessel. However, the hollow guidewire or other elongate structure increases a diameter of the contralateral portion of the delivery system and increases the number of steps involved in providing and/or removing contralateral access. Thus, it may be desirable to provide a delivery system in which the contralateral guidewire is directly secured to the ipsilateral portion of the delivery system to both reduce the diameter of the contralateral portion of the delivery system and/or reduce the number of steps to provide and/or remove contralateral access. Reducing the diameter of the contralateral portion reduces the size of the contralateral access. 
     Other devices and techniques use gate cannulation to access the contralateral limb of the stent graft above the bifurcation, which can be challenging and time consuming. Certain aspects of the present disclosure allow for easier deployment of the contralateral limb by providing a precannulated stent graft through the contralateral limb. The present disclosure can also allow the use of a larger guidewire (e.g., 0.035 in.). Precannulation of the contralateral limb eliminates gate cannulation, thereby simplifying the graft placement procedure. 
     Certain aspects of this disclosure are directed toward a locking assembly for releasably coupling a guidewire to a delivery catheter such that the guidewire can be released from the delivery catheter. In certain aspects of the locking assembly herein, a housing has a proximal end, a distal end, and a lateral wall portion. A recess extends at least partially through the lateral wall of the housing. A first lumen extends from the proximal end of the housing to the distal end of the housing along a longitudinal axis. A second lumen extends from the distal end of the housing, the diameter of the second lumen being less than the diameter of the first lumen. The second lumen is configured to receive and retain a guidewire. 
     Optionally, the locking assembly includes an elastomeric member that is retained in the recess. The elastomeric member can be configured to retain the guidewire when the guidewire extends into the second lumen. At least a portion of the elastomeric member can be substantially flush with an outer surface of the lateral wall of the housing. The elastomeric member can have an opening that at least partially aligns with the second lumen. The opening of the elastomeric member can have a diameter that is smaller than the diameter of the second lumen of the locking assembly to help retain a guidewire extending through the second lumen. 
     In certain aspects, the locking assembly has a protruding portion extending along at least a portion of the outer periphery of a distal portion of the housing to provide strain relief to the guidewire that extends distally from the second lumen. The second lumen can be positioned between the first lumen and the protruding portion. 
     Certain aspects of the present disclosure are directed toward a system utilizing the above-described locking assembly. The locking assembly can be fixed to a first elongate member. The system can also include a second elongate member configured to be retained by the second lumen alone or the second lumen in combination with the elastomeric member. 
     Certain aspects of the disclosure are directed toward a locking assembly that couples a contralateral guidewire to an ipsilateral catheter. The locking assembly has an anchoring portion configured to engage the ipsilateral catheter. The locking assembly has an interlock portion configured to retain a distal portion of the contralateral guidewire when the contralateral guidewire is advanced or retracted unless a vertical force between about 0.01 and about 6.0 lbf (e.g., between about 0.01 and about 0.5 lbf, between about 0.25 and about 0.75 lbf, between about 0.5 lbf and about 1.0 lbf, between about 0.75 lbf and about 1.15 lbf, between about 1.0 lbf and about 2.0 lbf, between about 1.5 lbf and about 2.5 lbf, between about 2.0 lbf and about 3.0 lbf, between about 2.5 lbf and bout 3.5 lbf, between about 3.0 lbf and about 4.0 lbf, between about 3.5 lbf and about 4.5 lbf, between about 4.0 lbf and about 5.0 lbf, between about 4.5 lbf and about 5.5 lbf, or between about 5.0 lbf and about 6.0 lbf, or otherwise) is applied to the contralateral guidewire. 
     Certain aspects of the present disclosure are directed toward a method of using the locking assembly described above. The method can include advancing a delivery system in a locked configuration. The delivery system can include a locking assembly fixed to the ipsilateral catheter. The locking assembly can include an interlock portion configured to retain the guidewire when the delivery system is in the locked configuration. A distal end of the guidewire can be introduced into the interlock portion from a distal side of the locking assembly such that the guidewire has a bend when the delivery system is in the locked configuration. The bend can be positioned between a proximal portion of the guidewire and the distal portion of the guidewire. The method can also include releasing the delivery system from the locked configuration to the unlocked configuration by advancing a release catheter along the guidewire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages will now be described in connection with certain embodiments, in reference to the accompanying drawings. The illustrated embodiments, however, are merely examples and are not intended to be limiting. The following are brief descriptions of the drawings. 
         FIG. 1A  is a schematic representation of a bifurcated vascular prosthesis for use with the present disclosure, positioned at the bifurcation between the abdominal aorta and the right and left common iliac arteries. 
         FIG. 1B  is an exploded view of a bifurcated graft for use with the present disclosure, showing a self-expanding wire support cage separated from an outer polymeric sleeve. 
         FIG. 2  is a schematic representation of an embodiment of the deployment catheter for delivering a bifurcated prosthesis, with a proximal portion of the main branch portion of the graft at least partially deployed. 
         FIG. 3  is a cross-sectional view of an embodiment of a deployment catheter for delivering a bifurcated prosthesis. 
         FIG. 4  is an enlargement of the portion delineated by curve  4 - 4  in  FIG. 3 . 
         FIG. 5  is a cross-sectional view of the embodiment of the deployment catheter shown in  FIG. 3  taken along line  5 - 5  of  FIG. 4 . 
         FIG. 6  is a cross-sectional view of the embodiment of the deployment catheter shown in  FIG. 3  taken along line  6 - 6  of  FIG. 4 . 
         FIG. 7  is a schematic representation of an embodiment of the deployment catheter with the guidewire sheath positioned across the bifurcation. 
         FIG. 8  is a schematic representation, as in  FIG. 7 , with the deployment catheter positioned in the aorta. 
         FIG. 9  is a schematic representation, as in  FIG. 8 , with the compressed iliac branches of the graft positioned partly within the iliac arteries. 
         FIG. 10  is a schematic representation, as in  FIG. 9 , with a proximal portion of the main branch portion of the graft at least partially deployed within the aorta. 
         FIG. 11  is a schematic representation, as in  FIG. 10 , following the further proximal retraction of the guidewire sheath and the contralateral branch sheath through the contralateral iliac artery, causing the deployment of the contralateral branch portion of the graft. 
         FIG. 12A  is a schematic representation, as in  FIG. 11 , following the proximal retraction of the ipsilateral branch sheath and deployment of the ipsilateral branch portion of the graft. 
         FIG. 12B  is a schematic representation, as in  FIG. 12A , following introduction of the release member at the contralateral access site and advancement of the release member along the contralateral guidewire. 
         FIG. 12C  is a schematic representation, as in  FIG. 12B , with a release member interfacing with a locking assembly. 
         FIG. 12D  is a schematic representation, as in  FIG. 12C , with a release member being retracted through the contralateral access site following decoupling of the contralateral guidewire from a locking assembly. In some embodiments, a cuff may be implanted (e.g., on a proximal end of the main branch portion) to secure or lengthen the graft. 
         FIG. 13A  is a schematic representation of a locking assembly configured to releasably retain an elongate member. 
         FIG. 13B  is an isometric view of an exemplary embodiment of the locking assembly including a housing an elastomeric member. 
         FIG. 14  is an isometric view of an embodiment of the elastomeric member shown in  FIG. 13B . 
         FIG. 14A  is a top view of an embodiment of the elastomeric member shown in  FIG. 14 . 
         FIG. 14B  is a rear view of an embodiment of the elastomeric member shown in  FIG. 14 . 
         FIG. 14C  is a front cross--sectional view of an embodiment of the elastomeric member shown in  FIG. 14 . 
         FIG. 14D  is a front view of an embodiment of the elastomeric member shown in  FIG. 14 . 
         FIG. 15  is a front cross--sectional view of an embodiment of the present locking assembly. 
         FIG. 16  is a front cross-sectional view of an alternative embodiment of the present locking assembly. 
         FIG. 17A  is a front view of an embodiment of a locking assembly coupled to a contralateral guidewire. 
         FIG. 17B  is a front view of the embodiment depicted in  FIG. 17A  interfacing with a release member. 
         FIG. 18A  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18B  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18C  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18D  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18E  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18F  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18G  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18H  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18I  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18J  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18K  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18L  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18M  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18N  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18O  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18P  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18Q  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 18R  is an alternative embodiment of the locking assembly presently disclosed. 
         FIG. 19  is a side view of an embodiment of a contralateral guidewire. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is now directed to certain specific embodiments of the disclosure. In this description, reference is made to the figures wherein like parts are designated with like numerals throughout the description and the drawings. Described below are various embodiments of a delivery system for establishing a surgical platform having multiple guidewires. In some aspects, the present disclosure is directed to devices and methods for deploying a vascular graft for treatment of an abdominal aortic aneurysm, including a deployment catheter and a guidewire assembly which may be used to maintain access through an implanted vascular graft for subsequent catheterizations. 
     An abdominal aortic aneurysm usually arises in the infrarenal portion of the diseased aorta, for example, below the kidneys. The aneurysm often occurs near a site of vessel branching, making a bifurcated stent a well-suited device for treating the abdominal aortic aneurysm. Endoluminal implantation is an increasingly accepted technique for implanting vascular grafts. This procedure may involve femoral cut down access or percutaneously inserting a vascular graft or prosthesis by using a delivery catheter. This process eliminates the need for major surgical intervention, thereby decreasing the risks associated with vascular and arterial surgery. Various embodiments of catheter delivery systems for prosthetic devices are described herein. 
     Endovascular surgical procedures can use a guidewire to help position a catheter or place prosthesis. Guidewires can provide a surgical platform from which a physician can conduct a minimally-invasive medical procedure. In some instances, a physician may use multiple guidewires in a medical procedure. When multiple guidewires are used, a first guidewire may have at least one of its ends in a location that is different from at least one of the ends of a second guidewire. When multiple guidewires are used, at least a portion of a first guidewire may be located in proximity to at least a portion of a second guidewire. In some instances, one end of a first guidewire may be located next to a portion of a second guidewire while the other end of the first guidewire is at a location different from the location of the end of the second guidewire. A first guidewire may access the patient at one location and be joined within the patient to a second guidewire that accesses the patient from a different location. Guidewires that access the patient&#39;s body from different locations can be used to deploy a bifurcated stent, to seat a heart valve, or to perform an endovascular surgical procedure. 
     Certain current delivery systems for a bifurcated stent graft system or a graft having at least one branch portion may use two separate sheaths to deploy the distal segment of the graft before the proximal segment. The outer sheath is first retracted to deploy a portion of the mid-body and the contralateral limb. Then, the front sheath is advanced distally to deploy the distal end of the graft, See e.g., U.S. Pat. No. 6,660,030. Other delivery systems, for example as disclosed in U.S. patent application Ser. No. 11/522,292, titled “A MULTI-SEGMENTED GRAFT DEPLOYMENT SYSTEM” and filed on Sep. 15, 2006 (the entirety of which is hereby incorporated by reference as if fully set forth herein) may use a plurality of axially spaced releasable restraint members temporarily connected by a pull wire to allow the distal main branch portion to be deployed before a proximal graft portion. Typically, these delivery systems are delivered to the aneurysm location over a guidewire. The guidewire may be further used to release a branch graft portion of the prosthesis, for example, by operably connecting a branch graft restraint mechanism to the guidewire and proximally withdrawing the guidewire from the vasculature. 
     Once the bifurcation graft has been deployed and implanted, a variety of procedures may desirably be accomplished. For example, it may be advantageous to implant a cuff (e.g., on the proximal end of the main branch portion) to secure the graft and thereby prevent movement or slippage of the main branch portion. Alternatively, it may be necessary to dilate the stenosis or touch up or re-establish the expansion of the graft. These procedures require advancing another catheter to the graft location along a guidewire. However, the positioning of a guidewire through the graft after the graft has been deployed is difficult since the tip of the guidewire may snag on the wire support cage of the graft. Thus, it may be advantageous to provide a guidewire assembly configured to remain placed through a graft once the graft has been deployed and to allow access through the expanded graft for subsequent catheterizations. Additionally, it may be advantageous to improve the configuration of the deployment catheter and/or the graft restraining members so as to improve the methods of deploying and positioning bifurcated and non-bifurcated grafts, as will be described herein. 
     In certain embodiments, the deployment catheter may be configured to deliver a graft that includes a main or distal graft portion and at least one branch or proximal graft portion. In certain embodiments, the hollow guidewire assembly may be associated with a restraint member for the branch segment, such that the branch segment may be deployed by the guidewire assembly. The guidewire assembly may be further configured such that it may be used to remove the restraint member from the branch segment while permitting placement and maintenance of a guidewire through the expanded branch segment and main body graft for subsequent catheterizations. Other embodiments of a graft deployment system and guidewire assembly will also be described below. 
     Prosthesis 
       FIG. 1A  is a schematic representation of an example of a bifurcated vascular graft  50  that can be used with any embodiment of the deployment catheter disclosed herein, positioned at the bifurcation between the abdominal aorta  30  and the right and left common iliac arteries  37  and  38 . With reference to  FIG. 1A , there is illustrated a schematic representation of the abdominal part of the aorta and its principal branches. In particular, the abdominal aorta  30  is characterized by a right renal artery  2  and left renal artery  4 . The large terminal branches of the aorta  30  are the right and left common iliac arteries  37  and  38 . Additional vessels (e.g., second lumbar, testicular, inferior mesenteric, middle sacral) have been omitted from  FIG. 1A  for simplification. One embodiment of an expanded bifurcated endoluminal vascular prosthesis is shown spanning aneurysms  103 ,  104  and  105 . The expanded bifurcated endoluminal vascular graft  50  can comprise a main branch portion  52  (also referred to herein as a main branch segment) for traversing the aorta, a first branch portion  54  (also referred to herein as a first branch segment or an ipsilateral branch portion) for spanning an ipsilateral iliac artery  37 , and a second branch portion  56  (also referred to herein as a second branch segment or a contralateral branch portion) for spanning a contralateral iliac artery  38 . 
     The terms “first” and “second” may be used interchangeably. In one embodiment, the first branch portion can refer to a downstream or upstream portion of a main branch vessel. For example, in one embodiment, the main branch portion and the first branch portion are configured to lie within at least a portion aortic arch (including, for example, the ascending and/or descending aorta) with main branch portion positioned closer to the heart while the second branch portion can be configured to extend into one of the branch vessels (left subclavian, right subclavian or carotid) that extend from the aortic arch. 
       FIG. 1B  is an exploded view of the bifurcated graft  50  of  FIG. 1A , which can include a self-expanding wire support cage  60  and an outer polymeric sleeve  68 . In FIG.  1 B, the wire support  60  is shown separated from an outer polymeric sleeve  68 . In the illustrated embodiment, the polymeric sleeve  68  can be situated concentrically outside of the tubular wire support  60 . However, other embodiments may include a sleeve positioned instead concentrically inside the wire support or positioned on both the inside and the outside of the wire support. Alternatively, the wire support may be embedded within a polymeric matrix or layer which makes up the sleeve. The sleeve  68  may be attached to the wire support  60  by any of a variety of suitable manners known to those skilled in the art. 
     The tubular wire support  60  can comprise a main branch portion  62  for traversing the aorta, a first branch portion  64  (also referred to herein as an ipsilateral branch portion) for spanning an ipsilateral iliac and a second branch portion  66  (also referred to herein as a contralateral branch portion) for spanning a contralateral iliac. The main branch portion  62  and first ipsilateral branch portion  64  can be formed from a continuous single length of wire having a proximal end, a distal end and a central lumen extending therebetween. Alternatively, the first ipsilateral branch portion  64  may be formed of one or more lengths of wire pivotably connected to the proximal end of the main branch portion  62 . A second, contralateral branch component  66  may be formed of one or more lengths of wire pivotably connected to the proximal end of the main branch portion  62 . Each of the iliac branch components has a proximal end, a distal end and a central lumen extending therethrough. Construction of the graft from a three part cage conveniently facilitates the use of different gauge wire in the different components (e.g. 0.014 in. diameter main trunk and 0.012 in. diameter branch components). 
     In general, each of the components of the bifurcated endoluminal vascular graft  50  may vary considerably in diameter, length, expansion coefficient, and other parameters or characteristics, depending upon the intended application. For implantation within the aorta of a typical adult, the main branch portion  52  will have a length within the range of from approximately 2 in. or less to approximately 5 in. or more, and, typically within the range of from approximately 3.5 in. to approximately 4 in. The unconstrained outside expanded diameter of the main branch portion  52  will typically be within the range of from approximately 0.75 in. to approximately 1.5 in. The unconstrained expanded outside diameter of the main branch portion  52  can be constant or substantially constant throughout the length, or can be tapered from a relatively larger diameter at the distal end to a relatively smaller diameter at the bifurcation. In general, the diameter of the proximal end of the main branch portion will be on the order of no more than approximately 95% and often no more than approximately 85% of the diameter of the distal end of the main branch portion. The iliac branch portions  54  and  56  will typically be bilaterally symmetrical, having a length within the range of from approximately 0.4 in. to approximately 2.6 in., and a diameter within the range of from approximately 0.04 in. to approximately 0.79 in. 
     The collapsed prosthesis for use in accordance with the present disclosure has a diameter in the range of approximately 0.08 in, to approximately 0.39 in. The maximum diameter of the collapsed prosthesis can be in the range of approximately 0.12 in. to approximately 0.24 in. (12 to 18 French). Some embodiments of the deployment catheter, including the prosthesis, can have a diameter in the range of from approximately 18 to approximately 20 or approximately 21 French. Other embodiments can have a diameter as low as approximately 19 French, approximately 16 French, approximately 14 French, or smaller. After deployment, the expanded endoluminal vascular prosthesis may radially self-expand to a diameter anywhere in the range of approximately 0.8 in. to approximately 1.6 in. 
     Although certain prosthesis configurations are disclosed herein, these are only examples of prostheses which are deployable using the embodiments of a deployment catheter and guidewire assembly described herein. In other embodiments, the delivery system described below may be used to deliver and deploy other types of self-expandable bifurcated or multi-segmented prosthesis having a main branch portion and at least one branch graft portion, as will be apparent to those of skill in the art in view of the disclosure herein. For example, in other embodiments, certain features and aspects of the deployment catheter and guidewire assembly can be used to deploy a graft without a branch graft portion, a graft with only one branch portion and/or a graft with more than one graft portions. Further details and additional embodiments of the prosthesis described above can be found in U.S. Pat. Nos. 6,007,296, 6,187,036, and 6,197,049, the entirety of each of which is hereby incorporated by reference herein. 
     It should also be appreciated that, although the illustrated embodiments are described in the context of a bifurcated graft configured for the abdominal aorta, certain features and aspects of the delivery systems and methods described herein can be used in other portions of the vascular system. For example, it is anticipated that certain features and aspects of the systems and methods described herein can be adapted for use in the thoracic aorta. In some embodiments, the deployment catheter  120  (see  FIG. 3 ) may be configured to treat defects that may include, but are not limited to, abdominal aortic aneurysms, subclavian aneurysms, and thoracic aortic aneurysms, to name a few. It is also anticipated that certain features and aspects of the system described herein may be adapted to deliver a single straight graft segment to the thoracic aorta or other vessels or arteries within the body. 
     Delivery System 
     The expandable bifurcation graft  50  can be deployed at a treatment site with any of a variety of deployment catheters, as will be apparent to those of skill in the art. Any of the embodiments of the deployment catheters disclosed herein may comprise any of the materials, features, or other details of any deployment catheters suitable for deploying an expandable bifurcation graft known in the field. Further details and additional embodiments of the deployment catheter can be found in U.S. Pat. Nos. 8,236,040 and 8,523,931, the entirety of each of which is hereby incorporated by reference herein. 
     The deployment catheters herein disclosed can be used for deploying a self-expanding bifurcation graft known in the field, or in any of the embodiments disclosed in U.S. Pat. Nos. 6,090,128, 6,500,202, 6,660,030, 8,523,931, and U.S. Pat. Pub. 2008/0071343. The entirety of each of the above-referenced patents and published patent applications is hereby incorporated by reference in their entirety as if fully set forth herein. 
     With reference to  FIG. 2 , one method for using an embodiment of a deployment catheter  120  for treating an abdominal aortic aneurysm will be briefly described, without limitation. More detail regarding this deployment method will be described below.  FIG. 2  is a schematic representation of an embodiment of a deployment catheter  120  for delivering a bifurcated prosthesis or graft  50 , showing a proximal portion of the main branch portion  52  of the graft  50  at least partially deployed within the aorta for illustration purposes. As shown in  FIG. 2 , the deployment catheter  120  can be introduced into a patient&#39;s vasculature through a puncture site in the patient&#39;s ipsilateral artery. The deployment catheter  120  is not limited to treatment of an abdominal aortic aneurysm; it can be configured to treat other aneurysms as discussed more fully herein. Additionally, depending on the clinical requirements, the deployment catheter  120  can be introduced into the patient&#39;s vasculature through puncture sites other than an ipsilateral artery. For example, without limitation, the deployment catheter  120  can be introduced into the patient&#39;s vasculature through a contralateral artery, through a radial artery, or through a subclavian artery. 
     As illustrated in  FIG. 2 , the deployment catheter  120  can be advanced over a guidewire  226  to the desired location within the patient&#39;s aorta. The graft  50  illustrated in  FIG. 2  can include a main branch portion  52  constrained within a main branch sheath or member  186 , an ipsilateral branch portion  54  constrained within and ipsilateral branch sheath or member  188 , and a contralateral branch portion  56  constrained within a contralateral branch sheath or member  190 . Prior to the deployment of the main branch portion  52  of the graft  50  as shown in  FIG. 2 , the entire graft can be constrained within an outer sheath  128  of the deployment catheter  120 . In brief, the graft  50  can be exposed by retracting the outer sheath  128 , and the deployment catheter  120  can be manipulated so as to position the contralateral branch portion  56  in the contralateral artery  38 . 
     After positioning the graft  50  in the desired position, illustrated in  FIG. 2 , the main branch portion  52  of the graft  50  can be deployed by retracting a sheath release  166  (e.g., a cord, suture, wire, or likewise), which can cause the perforated main branch sheath  186  to tear along a side thereof. The remaining portion of the main branch portion  52  can be deployed by further withdrawing the sheath release  166 . The main branch sheath  186  can be attached to the sheath release  166 , allowing the main branch sheath  186  to be removed through the ipsilateral access site as the sheath release  166  is removed through the ipsilateral access site. In other configurations, the main branch sheath  186  can be separately withdrawn from the contralateral access site or with either the ipsilateral branch sheath  188  or the contralateral branch sheath  190 . 
     In the illustrated embodiment, the contralateral branch portion  56  of the graft  50  can be deployed by withdrawing a contralateral guidewire sheath  216  through a puncture site in the contralateral iliac artery  38 , causing the contralateral branch sheath  190  to be withdrawn. Similarly, the ipsilateral branch portion  54  of the graft  50  can be deployed by withdrawing the deployment catheter  120  through a puncture site in the ipsilateral iliac artery  37 , causing the ipsilateral branch sheath  188  to be withdrawn either before or after the contralateral branch sheath  190  is withdrawn. 
     The deployment method described with reference to  FIG. 2  is not intended to limit the applicability of the deployment catheter  120 . The deployment catheter  120  may be configured to deploy a straight, bifurcated, or any other graft configuration into any portion of an artery or other blood vessel in the body. In some embodiments, the deployment catheter  120  may be used to deploy grafts having anchoring elements that help secure the graft to the vessel wall as well as grafts that do not have anchoring elements. With this brief, non-limiting overview of one method of using the deployment catheter  120  having been described, additional features and configurations of the deployment catheter  120  and additional details of this and other deployment methods will now be described. 
       FIG. 3  is a cut-away side view of a non-limiting exemplary embodiment of a deployment catheter  120 . The inner core  132  of the deployment catheter  120  can include a guidewire lumen  154  and a sheath release lumen  156  extending longitudinally therethrough. The guidewire lumen  154  can be defined by a central tube  170  that can be disposed within inner core  132 . The guidewire lumen  154  can be defined by a hole bored along a longitudinal axis of the inner core  132 . In the illustrated embodiment, the guidewire lumen  154  can extend throughout the entire length of the tubular inner core  132 , having a distal exit port  158  and a proximal access port  160 , as will be understood by those of skill in the art. In use, the deployment catheter  120  can be advanced into position in the aorta over a guidewire  226  (shown in  FIG. 2 ) extending through the guidewire lumen  154 , as will be understood by those of skill in the art. A sheath release  166  (also may be referred to herein as a cord) can be routed through the sheath release lumen  156 . In the illustrated embodiment, the sheath release lumen  156  can extend through the entire length of the tubular inner core  132 , having a distal exit port  162  and a proximal access port  164 , as will be understood by those of skill in the art. 
     In the embodiment of the deployment catheter  120 , the guidewire lumen  154  can be co-planar with the centerline axis of the inner core  132  and the sheath release lumen  156 . However, this arrangement is not required. In some embodiments, the guidewire lumen  154  can be not coplanar with the centerline axis of the inner core  132  and the sheath release lumen  156 . Therefore, the inner core  132  may be configured so that the guidewire lumen  154  and the sheath release lumen  156  are formed at any desired position in the cross-section of the inner core  132 . 
       FIG. 4  is an enlargement of the portion delineated by the curve  4  in  FIG. 3 .  FIGS. 5 and 6  are a cross-sectional view of the embodiment of the deployment catheter  120  shown in  FIG. 3  taken along line  5 - 5  and line  6 - 6 , respectively, of  FIG. 4 . With reference to  FIGS. 4-6 , a bifurcated endoluminal graft  50  is illustrated in a compressed configuration within the deployment catheter  120 , prior to the advancement of the inner core  132  relative to the other sheath  128 . The graft  50  can comprise a distal aortic trunk or main branch portion  52 , a proximal ipsilateral branch portion  54 , and a proximal contralateral iliac portion  56 . In the illustrated embodiment, the aortic main branch portion  52  of the graft  50  can be constrained within a main branch sheath  186 . While the embodiment of main branch sheath  186  is shown with reference to compressing a main branch graft portion  52 , it is envisioned that the sheath  186  could alternatively be used to compress and deliver other portions of a multi-segmented vascular graft, such as a branch graft portion, the entire multi-segmented graft, or a single-segment, straight vascular graft. Further, in the illustrated embodiment, the ipsilateral branch portion  54  can be constrained with a tubular ipsilateral branch sheath  188  (also referred to herein as the first branch sheath), and the contralateral branch portion  56  (also referred to herein as the second branch sheath) can be constrained within a generally tubular contralateral branch sheath  190 . In the illustrated embodiment, the ipsilateral branch sheath  188  and the contralateral branch sheath  190  can be open-ended tubular sheaths. 
     The ipsilateral branch sheath  188  can constrain substantially the entire length of the ipsilateral branch portion  54  of the bifurcated graft  50 . Similarly, in the illustrated embodiment, the contralateral branch sheath  190  can constrain substantially the entire length of the contralateral branch portion  56  of the bifurcated graft  50 . However, in some embodiments, the ipsilateral branch sheath  188  and/or the contralateral branch sheath  190  may constrain substantially more or less than the entire length of the ipsilateral branch portion  54  or the contralateral branch portion  56 , respectively, of the bifurcated graft  50 . 
     With reference to  FIG. 5 , the main branch sheath  186  can be sized and configured to circumferentially surround the main branch portion  52  of the bifurcated graft  50 . However, in some embodiments, the main branch sheath  186  can be configured to only partially surround the main branch portion  52  of the bifurcated graft  50 . The main branch sheath  186  may extend to the distal end of the contralateral branch portion  56  of the graft  50 . In some embodiments, the main branch sheath  186  can be configured so as to define a notch  192  along the portion of the length of the main branch sheath  186  that covers the contralateral branch portion  56 . In some embodiments, the notch  192  can be a slit along a portion of the length of the main branch sheath  186 . In some embodiments, as in the illustrated embodiment, the notch  192  can remove a portion of the main branch sheath  186  along a portion of the length of the main branch sheath  186  that can be less than or equal to approximately half of the perimeter of the main branch sheath  186 . In some embodiments, the main branch sheath  186  can be skived to remove a suitable amount of the material comprising the main branch sheath  186  to allow the ipsilateral or contralateral branch portion  54 ,  56  of the graft  50  to deploy upon retraction of the outer sheath  128 . Thus, in some embodiments, the main branch sheath  186  may not constrain the ipsilateral or contralateral branch portion  54 ,  56  of the bifurcated endoluminal graft  50 . 
     In some embodiments, as illustrated in  FIG. 4 , a torsion tab  196  can be integrally formed with the central tube  170 , or secured thereto such as by thermal bonding, adhesive bonding, and/or any of a variety of other securing techniques known in the art. As is illustrated, the main branch portion  52  of the bifurcated endoluminal graft  50  can be constrained by the main branch sheath  186  around the torsion tab  196 . In the illustrated embodiment, the torsion tab  196  can engage with the endoskeleton or, with reference to  FIG. 1B , the wire support cage  60  of the bifurcated graft  50  and ensures that the bifurcated graft  50  substantially rotates with the inner core  132  of the deployment catheter  120 . In other words, the torsion tab  196  can prevent the central tube  170  from rotating relative to the bifurcated graft  50 . This can enhance the ability of the medical practitioner or user to rotate and, hence, maneuver, the graft  50  and the ipsilateral and/or contralateral branch portions  54 ,  56  within the patient&#39;s aorta by rotating the proximal end of the deployment catheter  120 , in particular, by rotating the proximal end of the inner core  132  or the “Y” connector  169 . As such, the torsion tab  196  can cause the bifurcated endoluminal graft  50  to rotate substantially in unison with the central tube  170 . 
     As described in greater detail below, a locking assembly  300  can couple with the central tube  170 . The locking assembly  300  may be integrally formed with the central tube  170 , or secured thereto such as by thermal bonding, adhesive bonding, and/or any of a variety of other securing techniques known in the art. The locking assembly  300  can engage a locking portion  194   b  (shown in  FIG. 17A ) of a contralateral guidewire  194 . The locking portion  194   b  is also referred to herein as a distal end  194   b  or as a stiff region. The contralateral guidewire  194  can extend distally from the locking assembly  300  and cannulate the guidewire sheath  216 . The contralateral guidewire  194  can then bend proximally back and extend through the main branch portion  52  of the graft  50  and into the contralateral branch portion  56  of the graft  50 . The contralateral guidewire  194  and the contralateral guidewire sheath  216  can extend proximally from the contralateral branch portion  56  of the graft  50  and bend back distally, running distally along a gap formed between an inner surface of the outer sheath  128  and an outer surface of the main branch sheath  186 . The contralateral guidewire  194  and contralateral guidewire sheath  216  can then exit the delivery catheter  120  through a gap formed between a proximal face of the distal tip  174  and a distal face of the outer sheath  128 . The distal tip  174  may include a groove (not shown) that accommodates the contralateral wire  194  as the contralateral wire  194  passes through the junction between the distal tip  174  and the outer sheath  128 . 
     The contralateral branch sheath  190  can be deployed using the contralateral guidewire sheath  216 . The ipsilateral branch sheath  188  can be connected to the inner core  132  or the interface member  168  and adapted to be axially proximally withdrawn from the ipsilateral branch portion  182  of the graft  178 , thereby permitting the ipsilateral branch portion  182  to expand to its implanted configuration. The main branch sheath  186  can retracted with the contralateral branch sheath  190  or with the ipsilateral branch sheath  188 . 
     Method of Use 
     With reference to the embodiments of the deployment catheter  120  described above, an exemplary procedure or method of using the deployment catheter  120  to treat a patient&#39;s abdominal aortic aneurysm using the embodiments of the bifurcated endoluminal graft  50  disclosed above will now be described. However, the methods and devices of the present disclosure are not to be taken as limited to this particular illustrative example. The present methods and systems can be used in any medical procedure where one desires to reversibly couple catheters, sheaths, guidewires, or similar devices. 
     In the illustrated embodiment the main branch sheath  186  and the ipsilateral branch sheath  188  are introduced into the patient through the ipsilateral access site and removed from the patient through the ipsilateral access site, while the contralateral branch sheath  190  is introduced through the ipsilateral access site and removed through the contralateral access site. 
       FIG. 7  is a schematic representation of an embodiment of the deployment catheter  120  with the contralateral guidewire sheath  216  positioned across the bifurcation and within the contralateral iliac artery  38 . The hollow contralateral guidewire sheath  216  can be introduced into the ipsilateral iliac artery  37  through an ipsilateral access site in the femoral artery, advanced superiorly towards the aorta  30 , and using cross-over techniques known to those skilled in the arts, subsequently advanced inferiorly down the contralateral iliac artery  38  and out a contralateral access site in the contralateral femoral artery. The leading portion  216   b  of the contralateral guidewire sheath  216  can be externalized by passing the leading portion  216   b  of the contralateral guidewire sheath  216  through the contralateral access site. As discussed below, the guidewire sheath  216  can be secured to the contralateral branch sheath  190 . The contralateral branch portion  56  of the bifurcated graft  50  can be deployed by withdrawing the contralateral guidewire sheath  216  and thereby removing the contralateral branch sheath  190  from the contralateral branch portion  56  of the graft  50 . The contralateral branch sheath  190  can be removed through the contralateral access site by pulling on the contralateral guidewire sheath  216 . 
       FIG. 8  is a schematic representation, as in  FIG. 7 , with the deployment catheter  120  positioned in the aorta  30 . Referring to  FIG. 8 , after the contralateral guidewire sheath  216  the has been positioned across the bifurcation  228  in the aorta  30 , the deployment catheter  120  can then be advanced over a second guidewire  226  (also referred to as the main guidewire), such as but not limited to a standard 0.035 in. guidewire, from the ipsilateral access site into the aorta  30  using techniques known to those skilled in the arts. Traction can be applied to the hollow contralateral guidewire sheath  216  from the contralateral access site to take up the slack in the contralateral guidewire sheath  216  as the deployment catheter  120  is advanced into the aorta  30 . 
       FIG. 9  is a schematic representation with the ipsilateral and contralateral branch portions  54 ,  56  of the graft  50  compressed within the ipsilateral and contralateral branch sheaths  188 ,  190  (respectively) and positioned substantially fully within the respective ipsilateral and contralateral iliac arteries. As shown in  FIG. 9 , the bifurcated graft  50  can be configured so as to abut against the bifurcation of the aorta  228  or be positioned in the vicinity of the bifurcation of the aorta  228  by retracting the deployment catheter  120  and, if desired, the contralateral guidewire sheath  216  until the bifurcated graft  50  abuts or is in the vicinity of bifurcation of the aorta  228 . The contralateral guidewire  194  can be manipulated so as to seat the graft  50  onto the bifurcation  228  of the aorta  30 . 
       FIG. 10  is a schematic representation, as in  FIG. 9 , with a proximal portion of the main branch portion  52  of the graft  50  or at least partially deployed within the aorta  30 . The proximal portion of the main branch portion  52  of the graft  50  can be partially deployed within the aorta  30  as illustrated by proximally retracting the sheath release wire  166 , as described above, while holding the inner core  132  of the deployment catheter (see  FIG. 3 ) in a fixed position relative to the aorta  30  so as to prevent exerting undue force on the bifurcation  228  of the aorta  30  or other portions of the anatomy. Deploying the graft  50  in a bottom up sequence, as illustrated herein, may help mitigate the “wind socking” effect that can cause proximal migration of the graft  50 . Additionally, deploying the graft  50  and a bottom up sequence may allow for either axially or rotationally repositioning of a partially deployed graft  50  without causing significant or any damage to the arterial wall. In some embodiments, this may partly be due to the fact that the deployed middle portion of the graft  50  may move against the arterial wall more easily than a deployed end portion of the graft  50 . The main branch sheath  186  can be attached to the sheath release wire  166  and withdrawn from the patient through the ipsilateral access site. 
       FIG. 11  is a schematic representation, as in  FIG. 10 , following the further proximal retraction of the contralateral guidewire sheath  216  and, consequently, the contralateral branch sheath  190 , through the contralateral iliac artery  38 . As illustrated therein, the contralateral branch sheath  190  has been retracted so as to completely deploy the contralateral branch portion  56  of the bifurcated graft  50 . The contralateral guidewire  194  may remain coupled to the locking assembly  300  as the contralateral guidewire sheath  216  is withdrawn through the contralateral access site. 
       FIG. 12A  is a schematic representation, as in  FIG. 11 , following the proximal retraction of the ipsilateral branch sheath  188  and deployment of the ipsilateral branch portion  54  of the graft  50 . The ipsilateral branch portion  54  of the graft  50  may be deployed by proximally retracting the inner core  132  which, as described above, can be directly or indirectly rigidly attached to the ipsilateral branch sheath  188  (see  FIG. 3 ). Because the ipsilateral branch sheath  188  can be an open-ended tubular sheath, the ipsilateral branch portion  54  of the graft  50  can be deployed in a top down sequence. 
     However, the ipsilateral branch sheath  188  (and the contralateral branch sheath  190 ) can be configured to accommodate any other desired or suitable sequence. In some embodiments, the ipsilateral branch portion  54  of the bifurcated graft  50  may be deployed before deployment of the contralateral branch portion  56  of the graft  50 . Additionally, although the figures illustrate the main branch portion  52  of the graft  50  being deployed with the contralateral branch portion  56 , in other embodiments, the main branch portion  52  of the graft  50  may be deployed with the ipsilateral branch portion  54 . Also, although the figures illustrate the ipsilateral branch portion  54  being deployed before the contralateral branch portion  56 , in other methods, the contralateral branch portion  56  may be deployed before the ipsilateral branch portion  54  of the graft  50 . 
     In the illustrated embodiment depicted in  FIG. 12A , the contralateral guidewire  194  remains coupled to the locking assembly  300  after deployment of the bifurcated graft  50 . The locking assembly  300  retains the distal end  194   b  (shown in  FIG. 17A ) of the contralateral guidewire  194  to prevent unintended movement of the distal end of the contralateral guidewire  194 . The locking assembly  300  can be configured to allow the medical technician to actuate the locking assembly  300 , thereby triggering the locking assembly  300  to release the distal end of the contralateral guidewire  194 . 
     Referring to  FIGS. 12B-D , release of the contralateral guidewire  194  from the locking assembly  300  may be accomplished by advancing a release member  311  (e.g., pigtail catheter) along the contralateral guidewire  194 . The release member  311  can then directly or indirectly apply a vertical force to the contralateral guidewire  194 , thereby causing the locking assembly  300  to release the distal end  194   b  of the contralateral guidewire  194 . The release member  311  can then be withdrawn through the contralateral access site. The contralateral guidewire  194  can be withdrawn before, after, or at the same time as the withdrawal of the release member  311 . Additionally or alternatively, the release member  311  can be configured to release the contralateral guidewire  194  upon the activation of a triggering element that is coupled to the locking device  300 , as described below. 
     Although the illustrated method shows the ipsilateral branch portion  54  of the graft  50  being released before withdrawing the contralateral guidewire  194 , in some methods, the contralateral guidewire  194  may be released (e.g., as shown in  FIGS. 12B-12D ) prior to releasing the ipsilateral branch portion  54  (e.g., as shown in  FIG. 12A ). 
     Locking Assembly 
       FIG. 13A  is a schematic representation of a locking assembly  300 . The locking assembly  300  may be interfaced with (e.g., removably coupled, permanently secured, or integrally formed with) a first elongate member  303  and a second elongate member  305 . The locking assembly  300  may be configured to interface with more than two elongate members. The first elongate member  303  may pass through the locking assembly  300 . The locking assembly  300  can interface with an anchor portion  307  of the first elongate member  303 . The locking assembly  300  may reversibly couple to a locking portion  309  of the second elongate member  305 . 
       FIG. 13B  is a non-limiting example of a locking assembly  300  that can be used with any embodiment of the deployment catheter  120  disclosed herein. In general, the locking assembly  300  presently disclosed can be configured to secure two elongate members to the locking assembly  300 . The locking assembly  300  can be adapted to release one of the elongate members from the locking assembly  300  when a user applies a vertical force to the elongate member being released. The locking assembly  300  presently disclosed can be used in medical procedures that employ a junction of two wires from different locations, such as procedures deploying bifurcated stents or multiple stents in thoracic, renal, or cardiac procedures. By way of a non-limiting example, the locking assembly  300  can be used to join a contralateral guidewire to an ipsilateral catheter when deploying a bifurcated stent in order to treat an abdominal aortic aneurysm. Certain aspects of the locking assembly  300  will now be described by presenting a variety of non-limiting exemplary embodiments of the locking assembly  300 . 
     Referring to  FIG. 13B , the locking assembly  300  can include a housing  301  having a distal face  302  and a proximal face  304 . As shown in  FIG. 13B , the proximal and distal faces  304 ,  302  may be substantially perpendicular to the longitudinal axis  306 . However, in other configurations the proximal and distal faces  304 ,  302  may not be substantially perpendicular to the longitudinal axis  306  and/or parallel with each other. The locking assembly  300  can include an anchoring surface  308  that defines a first lumen  310 . The first lumen  310  may communicate between the distal face  302  and the proximal face  304  of the housing  301 . As shown in  FIG. 13B , the first lumen  310  may be concentric to the longitudinal axis  306  of the locking assembly  300 . However in other configurations, the first lumen  310  may be off-center of the longitudinal axis  306  of the locking assembly  300 . 
     The elongate member can pass through the first lumen  310  of the locking assembly  300 , e.g., the central tube  170  of the delivery catheter  120  can pass through the first lumen  310 . The locking assembly  300  can be integral with the central tube  170  or bonded to the central tube  170  so that there is no relative movement between the locking assembly  300  and the central tube  170  as the central tube  170  is moved in a distal or proximal direction. The central tube  170  can be secured to the anchoring surface  308  such as by thermal bonding, adhesive bonding, crimping, or any of a variety of other securing techniques known in the art. 
     Additionally or alternatively, the locking assembly  300  can include a second lumen  312 . The second lumen  312  is a passage between the distal face  302  and the proximal face  304  of the housing  301 . However, in other configurations, the second lumen  312  may communicate only with the distal face  302 , and not with the proximal face  304 , of the housing  301 . The second lumen  312  can be configured to retain a second elongate member (e.g., the contralateral guidewire  194 ) to the locking assembly  300 . The contralateral guidewire  194  can be released from the second lumen  312  upon activation of the locking assembly  300  by a user. 
     The locking assembly  300  can include a first recess  314  that extends from a lateral wall  316  of the housing  301  toward the longitudinal axis  306  of the locking assembly  300 . The second lumen  312  can communicate with the first recess  314 . Additionally or alternatively, the first lumen  310  can communicate with the first recess  314 . The locking assembly  300  can include a second recess  320  that extends from the lateral wall  316  of the housing  301  toward the longitudinal axis  306  of the locking assembly  300 . The locking assembly  300  can include a divider  322  that is interposed between the first recess  314  and the second recess  320 . The locking assembly  300  can include a through-hole  324  that extends through the divider  322  and communicates between the first and second recesses  314 ,  320  to form a recessed portion. 
     A proximal portion  326  of the locking assembly  300  can be tapered. The proximal portion  326  can be tapered so that the transverse cross-sectional area of the proximal portion  326  decreases along the proximal direction. The proximal portion  326  can be tapered to allow the proximal portion  326  to be withdrawn out of the graft  50  and back into the outer sheath  128  without having the locking assembly  300  getting caught on the graft  50  or the outer sheath  128  or any other intervening structure. The locking assembly  300  can have a taper angle defined as the angle between the longitudinal axis  306  of the locking assembly  300  and the lateral wall of the proximal portion of the locking assembly  300 . The taper angle can be between about 15 and 60 degrees, between about 20 and 45 degrees, and between about 25 and 35 degrees. The taper angle can be 30 degrees with a tolerance of 1 degree. 
     A distal portion  330  of the locking assembly  300  can include a protrusion  332 , extending radially outward from housing  301 . The protrusion  332  may circumferentially surround the entire distal portion  330  of the locking assembly  300 , or may surround only a portion of the distal portion  330  of the locking assembly  300 . The protrusion  332  may extend from only a portion of the distal portion  330 . The second lumen  312  can be interposed between the protrusion  332  and the first lumen  310 . The protrusion  332  can be configured to provide strain relief to an elongate member that extends distally from the second lumen  312  and then bends back in the proximal direction. The protrusion  332  can have a radius of curvature between about 0.005 and 0.1 inches, between about 0.01 and 0.05 inches, and between about 0.015 and 0.025 inches. The protrusion  332  can have a radius of curvature of 0.02 inches with a tolerance of 0.01 inches. 
     The locking assembly  300  can have a length dimension that defines the distance between the proximal and distal faces  304 ,  302 . The length dimension can be between about 0.1 and 1.0 inches, between about 0.2 and 0.5 inches, and between about 0.3 and 0.4 inches. The length dimension can be 0.375 inches with a tolerance of 0.010 inches. The locking assembly  300  can have a width dimension perpendicular to the length dimension. The width dimension can be between about 0.05 and 0.5 inches, between about 0.1 and 0.3 inches, and between about 0.15 and 0.2 inches. The width dimension can be 0.187 inches with a tolerance of 0.002 inches. The locking assembly  300  can have a first aspect ratio defined as the length dimension divided by the width dimension. The first aspect ratio can be between about 0.5 and 5, between about 1 and 3, and between about 1.75 and 2.25. The first aspect ratio can be 2.0. 
     The first lumen  310  of the locking assembly  300  can have a diameter of between about 0.01 and 0.2 inches, between about 0.02 and 0.1 inches, and between about 0.04 and 0.06 inches. The first lumen  310  can have a diameter of 0.055 inches with a tolerance of 0.002 inches. The second lumen  312  of the locking assembly  300  can have a diameter of between about 0.01 and 0.1 inches, between about 0.02 and 0.05 inches, and between about 0.03 and 0.04 inches. The second lumen  312  can have a diameter of 0.033 inches with a tolerance of 0.002 inches. The locking assembly  300  can have a second aspect ratio defined as the diameter of the first lumen  310  divided by the diameter of the second lumen  312 . The second aspect ratio of the locking assembly  300  can be between about 1 and 3, between about 1.5 and 2. The second aspect ratio of the locking assembly  300  can be 1.667. The center points of the first and second lumens can be separated from one another by a spacing dimension. The spacing dimension can be between about 0.04 and 0.07 inches, and between 0.05 and 0.06 inches. The spacing dimension can be 0.053 inches with a tolerance of 0.002 inches. 
     The locking assembly  300  can include an elastomeric member  334 . The elastorneric member  334  may occupy at least a portion of the first recess  314 . The elastomeric member  334  can have an outer surface  336  that is flush with at least a portion of the lateral wall of the locking assembly  300 . The first recess  314  can be configured to retain the elastomeric member  334  within the locking assembly  300 . Additionally or alternatively, the elastomeric member  334  may occupy at least a portion of the second recess  320 . The second recess  320  can be configured to retain the elastomeric member  334  within the locking assembly  300 . The elastomeric member  334  can be configured to span the divider  322 . The elastomeric member  334  can have a first portion that resides in the first recess  314  while a second portion of the elastomeric member  334  resides in the second recess  320 , the first and second portions of the elastomeric member  334  being connected by a segment of the elastorneric member  334  that extends through the through-hole  324 . 
     The elastomeric member  334  can be configured to enhance the ability of the second lumen  312  to retain the contralateral guidewire  194  of the delivery catheter  120 . For example, the elastomeric member  334  can be configured to intrude into at least a portion of the second lumen  312 . The locking assembly  300  can be configured so that at least a portion of the elastomeric member  334  can interface with an elongate member inserted into the second lumen  312 . The elastomeric member  334  may form a friction fit with an elongate member inserted into the second lumen  312 , helping to retain the elongate member in the second lumen  312 . Different non-limiting exemplary embodiments of the elastomeric member  334  are discussed below. 
       FIG. 14  shows an isometric view of one exemplary embodiment of the elastomeric member  334 . The elastomeric member  334  can include a first portion  340  that is configured to be retained within the first recess  314  of the locking assembly  300 . Additionally or alternatively, the elastomeric member  334  may include a second portion  342  that is configured to be retained within the second recess  320  of the locking assembly  300 . The first portion  340  can be connected to the second portion  342  by at least one segment  344 . In the non-limiting exemplary example depicted in  FIG. 14  the elastomeric member  334  can include a first portion  340  joined to a second portion  342  by two segments  344 , the segments  344  being cylindrical in shape. The elastomeric member  344  can include a segment  344  having a shape other than cylindrical. The second portion  342  and the segment  344  can be configured to enhance retention of the elastomeric member  334  within the housing  301  of the locking assembly  300 . The second portion  342  can provide a mechanical lock between the elastomeric member  334  and the housing  301  of the locking assembly  300 , thereby increasing the strength of the attachment between the elastomeric member  334  and the housing  301 . 
     The elastomeric member  334  can include a retention portion  346  configured to retain a second elongate member  305  that is inserted into the second lumen  312  of the locking assembly  300 . The retention portion  346  can define an opening  348  (e.g., through-hole, lumen, or otherwise) that extends at least partially through the elastomeric member  334 , e.g., between a distal face  350  and a proximal face  352  of the elastomeric member  334  or only in communication with the distal face  350  of the elastomeric member  334 . The opening  348  can be concentric with the second lumen  312  of the locking assembly  300  when the elastomeric member  334  is seated within the first recess  314  of the locking assembly  300 . 
     An end portion of the opening  348  has a diameter  356  that can be larger than an intermediate diameter  360  of an intermediate portion  362  of the retention portion  346 . The end portion  354  of the retention portion  346  can be configured to guide an elongate member into the intermediate portion  356  of the retention portion  346 . The end portion  354  of the retention portion  346  can include a canted wall that funnels an inserted elongate member into the intermediate portion  356  of the retention portion  346 . 
     The elastomeric member  334  can include a passageway defined by a curved surface  364  that aligns with the first lumen  310  of the locking assembly  300 . The curved surface  364  of the elastomeric member  334  can interface with (e.g., by bonding) the housing  301  of the locking assembly  300 . The housing  301  of the locking assembly can interface with (e.g., by welding) to the elongate member that passes through the first lumen of the locking assembly  300 . 
     The elastomeric member  334  can include a curved portion  366 . The curved portion  366  can be configured to enhance the bonding between the elastomeric member  334  and the housing  301  of the locking assembly  300 .  FIG. 14A  is a top view of the elastomeric member  334  depicted in  FIG. 14 .  FIG. 14B  is an offset rear view of the elastomeric member  334  depicted in  FIG. 14 , showing the curved portion  366  in more detail.  FIG. 14C  is a front cross-sectional view of the elastomeric member  334  depicted in  FIG. 14 .  FIG. 14D  is an offset front view of the elastomeric member  334  depicted in  FIG. 14 . 
       FIG. 15  depicts a cross-sectional view of an exemplary embodiment of the locking assembly  300 . The elastomeric element  334  can include a retention portion  346  that at least partially aligns with the second lumen  312 . The retention portion  346  can include an opening  348  having a width  370 . The width  370  of the passageway of the retention portion  346  can be smaller than the width  372  of the second lumen  312 , thereby causing at least a portion of the retention portion  346  to intrude upon the second lumen  312 . The retention portion  346  can define an opening  348  that partially aligns with the second lumen  312 . For example, the retention portion  346  may intrude upon the second lumen  312  from only one side. In some configurations, the retention portion  346  can be cup-shaped, with the mouth of the cup-shaped retention portion  346  facing the distal surface  302  of the locking assembly  300 . 
     As discussed, in some embodiments, the retention portion  346  can include an opening  348  formed within the elastomeric member  334 . The elastomeric member  334  can be made of an elastic material such as silicone. The opening  348  of the retention portion  346  can stretch and/or compress to accommodate an elongate member inserted into the retention portion  346 . The retention portion  346  can be configured to form a friction fit with an elongate member inserted into the opening  348  of the retention portion  346 . The friction fit between the retention portion  346  and the elongate member can resist distal movement of the elongate member relative to the retention portion  346  until the elongate member is subjected to sufficient tension in the distal direction. 
       FIG. 16  depicts a cross-sectional view of a non-limiting alternative embodiment of the locking assembly  300 ′ that includes the housing  301 ′ but not include an elastomeric member  334 ′. The housing  301 ′ can be substantially similar to that described above except without a recessed portion configured to receive the elastomeric member. In this embodiment, the locking assembly  300 ′ can include a retention portion  346 ′ which can include the second lumen  312 ′. The second lumen  312 ′ can have a uniform cross-sectional area or a non-uniform cross-sectional area (e.g., a constriction of the second lumen  312 ′). A distal portion  374 ′ of the second lumen  312 ′ can have a width  376 ′ that is greater than a width  380 ′ of an intermediate portion  382 ′ of the second lumen  312 ′. The second lumen  312 ′ may include a proximal portion  384 ′ that is proximal of the intermediate portion  382 ′ of the second lumen  312 ′. The proximal portion  384 ′ can have a width  386 ′ that is greater than the width  380 ′ of the intermediate portion  382 ′. The operation of the retention portion  346 ′ is discussed below. 
       FIGS. 17A and 17B  schematically illustrate a method of releasing the guidewire from the locking assembly  300  that can be used in connection with both the locking assemblies with and without the elastomeric member (shown in  FIGS. 15 and 16 ). Although these figures illustrate the second lumen  312 ″ having a generally uniform diameter, the diameter may vary as shown in  FIG. 16 .  FIG. 17A  depicts a non-limiting exemplary embodiment of the locking assembly  300 ″ with a distal portion  194   b  (also called the locking portion) of the contralateral guidewire  194  inserted into the second lumen  312 ″ of the locking assembly  300 ″. When the contralateral guidewire  194  is inserted into the locking assembly  300 ″, general advancement and retraction of the contralateral guidewire  194  without the appropriate vertical force and/or actuation will not release the contralateral guidewire  194  from the locking assembly  300 ″. 
     The contralateral guidewire  194  can include multiple regions, with each region having a different stiffness. For example, the stiffness of the locking portion  194   b  of the contralateral guidewire  194  can be selected to be higher than the stiffness of a proximal portion  194   a  (also called the floppy region) of the contralateral guidewire  194 .  1941941941   94 By designing the floppy region  194   a  to have a low stiffness, the a proximal portion  194   a  of the contralateral guidewire  194  will be sufficiently flexible to avoid causing damage to surrounding tissue. The tensile strength of the floppy region  194   a  can be greater than about 1 lbf, greater than about 2 lbf, greater than about 6 lbf, and greater than about 8 lbf. 
     The locking portion  194   b  of the contralateral guidewire  194  can extend from the floppy region  194   a  of the contralateral guidewire  194  at an interface  406 ″. The length  410 ″ of the locking portion  194   b  can be selected from different lengths. In some embodiments, the length of the locking portion  194   b ″ can be between about 0.3 and 0.8 cm. Additionally or alternatively, the insertion depth of the locking portion  194   b  into the second lumen  312 ″ can be adjusted. The contralateral guidewire  194  and the locking assembly  300 ″ may be tailored so that the interface  406 ″ can be located distal, proximal, or co-planar to the distal face  302 ″ of the locking assembly  300 ″. 
     During use, a user may pull on the contralateral guidewire  194 , creating a tension  412 ″ in the contralateral guidewire  194 , thereby causing the contralateral guidewire  194  to bend in the proximal direction, as illustrated in  FIG. 17A . Additionally or alternatively, a user may push on the contralateral guidewire  194 , causing a compressive force  414 ″ that buckles the contralateral guidewire  194  in the distal direction, thereby pushing the locking portion  194   b  into the retention portion  346 ″. The locking assembly  300 ″ can include a protrusion  332 ″ that provides strain relief to the contralateral guidewire  194  when the contralateral wire  194  bends back in the proximal direction. The position of the interface  406 ″ relative to the distal face  302 ″ of the locking assembly  300 ″ can be selected so that as the tension  412 ″ pulls on the interface  406 ″, the locking portion  194   b  of the contralateral guidewire  194  is retained against a lateral surface  416 ″ of the retention portion  346 ″, thereby preventing the contralateral guidewire  194  from decoupling from the locking assembly  300 ″. The clearance between the locking portion  194   b  and the lateral surface  416 ″ can also be selected to further define the tension  412 ″ required to decouple the contralateral guidewire  194  from the locking assembly  300 ″. The locking assembly  300 ″ can be configured to release the locking portion  194   b  of the contralateral guidewire  194  when a force is applied to an intermediate portion of the contralateral guidewire  194  at an angle of less than or equal to about 60 degrees from the locking portion  194   b  of the contralateral guidewire  194  and/or at least about 45 degrees from the locking portion  194   b ″ of the contralateral guidewire  194 ″. 
       FIG. 17B  shows an illustrative embodiment of a locking assembly  300 ″ that is configured to release the contralateral guidewire  194  upon a release member  311  (e.g., pigtail catheter) contacting with the locking assembly  300 ″ and applying a vertical force to draw the locking portion  194   b  of the contralateral guidewire  194  out of the retention portion  346 ″. In the non-limiting exemplary locking assembly  300 ″ depicted in  FIG. 17B , the release member  311  can be a release sheath that is configured to be disposed over the contralateral guidewire  194 . The release member  311  may completely circumferentially surround the contralateral guidewire  194 , or the release member  311  may only partially circumferentially surround the contralateral guidewire  194 . The release member  311  may be composed of plurality of segments. The segments may be identical to one another or different from one another. Some, all, or no segments may completely circumferentially surround the contralateral guidewire  194  while some, all, or no other segments only partially surround the contralateral guidewire  194 . The segments may be separated from one another by one or more hinge points. The hinge points may be configured to allow the segments to bend, flex, or pivot relative to one another. 
     The release member  311  can be introduced at the contralateral access site by passing the distal end of the release member  311  over the proximal end of the contralateral guidewire  194 . The release sheath  420 ″ can be advanced over the contralateral guidewire  194  until the distal face of the release member  311  engages the distal face  302 ″ of the locking assembly  300 ″. The outer diameter of the distal face of the release member  311  can be selected so that the distal face abuts against the distal face  302 ″ of the locking assembly. As a user applies a compressive force  414 ″ to the release member  311  and contralateral guidewire  194 , the release member  311  buckles in the distal direction. As the release member  311  buckles (loops, forms a U-shape, or otherwise bends) in the distal direction, the portion of the contralateral guidewire  194  that distally extends from the retention member  346 ″ of the locking assembly  300 ″ is aligned to be substantially perpendicular to the distal face  302 ″ of the locking assembly  300 ″. A user may now apply tension  412 ″ to the contralateral guidewire  194 . Once a distally extending portion of the contralateral guidewire  194  is longitudinally aligned with the retention member  346 ″, the  194  the contralateral guidewire  194  is released from the retention member  346 ″. The locking assembly  300 ″ can be configured to retain the contralateral guidewire  194  until a vertical force of at least 0.1 lbf (or at least about 0.5 lbf, at least about 1.0 lbf, or otherwise) is applied to the contralateral guidewire  194 . 
     The reversible coupling of the contralateral guidewire  194  to the locking assembly  300  can be accomplished by alternative embodiments that are within the scope of the present disclosure. For example, the locking assembly  300 ″ depicted in  FIGS. 17A-B  can include an elastomeric member  334 , as discussed above. Additionally or alternatively, the locking assembly  300  can include any of the features depicted in the alternative embodiments depicted in  FIGS. 18A-R . 
       FIG. 18A  depicts an embodiment where the locking portion  194   b  of the contralateral guidewire  194  is retained by wrapping the locking portion  194   b  of the contralateral guidewire  194  over the main branch portion  52  of the graft  50 . The locking portion  194   b  can be secured to the outer surface of the main branch portion  52  by a sheath (not shown) that is deployed by a suture (not shown) as described above for the deployment of the main branch portion  52  of the graft  50 . The locking portion  194   b  may be larger in diameter, longer, and/or more rigid than remaining portions of the contralateral guidewire  194 . The sheath that secures the locking portion  194   b  can be the main branch sheath  186  or a sheath different from the main branch sheath  186 . 
       FIG. 18B  depicts an embodiment of the locking assembly  300  that can have a track  428  configured to retain the locking portion  194   b  of the contralateral guidewire  194 . The locking portion  194   b  may be larger and/or more rigid than a remaining portion of the contralateral guidewire  194  to help retain the locking portion  194   b  within the track  428 . The track  428  may be an open faced channel having a variable width so that when tension is applied to the contralateral guidewire  194  the locking portion  194   b  is drawn up into a necked region of the track  428 , thereby constraining the locking portion  194   b  from escaping the track  428 . Additionally or alternatively, a region of the track  428  may be an open faced channel having an enlarged region where the width of the track  428  is larger than the width of the locking portion  194   b . A user may free the contralateral guidewire  194  from the locking assembly  300  by advancing the locking portion  194   b  of the contralateral guidewire  194  until the locking portion  194   b  is aligned with the enlarged region of the track  428 , thereby allowing the locking portion  194   b  to escape the track  428 . 
       FIG. 18C  depicts an embodiment of the locking assembly  300  that has a retaining wire  430 . The retaining wire  430  can be configured to hold the contralateral guidewire  194  against the distal face  302  of the locking assembly  300 , thereby keeping the locking portion  194   b  within the retention portion  346  of the locking assembly  300 . The retention portion  346  can be a groove on the side of the housing  301  of the locking assembly  300 . The retention portion  346  may be a pocket  432  that is surrounded by the housing  301 . The width of the groove or pocket  432  may vary as described above. The retaining wire  430  can be configured to be withdrawn from the locking assembly  300 , thereby allowing the locking portion  194   b  to potentially release from the pocket  432 . 
       FIG. 18D  depicts an embodiment of the locking assembly  300  that has a clamp  434 . The top portion  436  of the clamp  434  may be pulled against the bottom portion  438  of the clamp  434  by a spring  440  that is connected to the top portion  436  by a tension element  442 . The contralateral guidewire  194  may be coupled to the locking assembly  300  by virtue of being compressed between the top and bottom portions  436 ,  438  of the clamp  434 . A user may activate a trigger  444  to compress the spring  440  reducing the tension element, thereby reducing the compressive force between the top and bottom portions  436 ,  438  of the clamp  434  and allowing the contralateral guidewire  194  to decouple from the locking assembly  300 . In other embodiments, the tension in the spring  440  may be released by moving the trigger  444  or by releasing the tension on the spring  440 . 
       FIG. 18E  depicts an embodiment of the :locking assembly  300  having a duckbill valve  446 . The duckbill valve  446  can be configured to retain a locking portion  194   b  at the distal end of the contralateral guidewire  194 . The locking portion  194   b  may be larger and/or more rigid than a remaining portion of the contralateral guidewire  194 . A user may decouple the contralateral guidewire  194  from the locking assembly  300  by advancing the contralateral guidewire  194  to allow the locking portion  194   b  to escape the duckbill valve  446 . 
       FIG. 18F  depicts an embodiment of the locking assembly  300  configured to retain a bead  448  attached to the contralateral guidewire  194 . The bead  448  can interface with (e.g., by bonding) the contralateral guidewire  194 . As shown in  FIG. 18F , the bead  448  can sit within a channel  445  that has a narrow proximal portion and a wider distal portion. The narrow proximal portion of the channel  445  can be configured to prevent the bead  448  from being pulled proximally through the channel. The wider portion of the channel can have an overhang  447  that can be configured to prevent the bead  448  from leaving the channel  445  unless the bead  448  is advance sufficiently far distally to clear the overhang  447 . 
       FIG. 18G  depicts an embodiment of the locking assembly  300  having a plastic retention member  390  (e.g., soft wing) that can be located within the main branch portion  52  of the graft  50 . The plastic retention member  390  can interface (e.g., by friction, press fit, molded, adhered, thermally bonded, mechanically locked, otherwise secured) with the central tube  170 . The contralateral guidewire  194  can extend distally through the graft  50 , pass over or through a housing member and bend proximally back into the graft  50  to terminate at the plastic retention member  390 . The locking portion  194   b  of the contralateral guidewire  194  can be configured to be retained by the plastic retention member  390  as described above in  FIG. 18B . 
       FIG. 18H  depicts an embodiment of the locking assembly  300  having a wrapper  450 . The wrapper  450  can enclose at least a portion of the housing  301  of the locking assembly  300 . The wrapper  450  can be configured to restrain the locking portion  194   b  of the contralateral guidewire  194  within a channel  452  formed in the side of the housing  301 . The wrapper  450  can be removed by a control suture  454 , thereby allowing the locking portion  194   b  to escape the channel  452 . 
       FIG. 18I  depicts an embodiment of the locking assembly  300  having a rigid sheath  456 . The rigid sheath  456  can be configured to press the contralateral guidewire  194  against an abutment  458 , thereby locking the contralateral guidewire  194  to the locking assembly  300 . The contralateral guidewire  194  may be decoupled from the locking assembly  300  by proximally withdrawing the rigid sheath  456  or distally advancing the abutment  458 . A control rod  460  attached to the abutment  458  can allow a user to distally advance the abutment  458 . The locking portion  194   b  may be larger and/or more rigid than a remaining portion of the contralateral guidewire  194  locking portion 
       FIG. 18J  depicts an embodiment of the locking assembly  300  having a curved groove  462 . The curved groove  462  may be S-shaped, U-shaped, sinusoidal, zig-zag-shaped or combinations thereof. The curved groove  462  may be formed in the outer surface of the housing  301  of the locking assembly  300  described above. The contralateral guidewire  194  may include a locking portion  194   b  that has a width or length that prevents the locking portion  194   b  from being pulled through the curved groove  462 . The locking assembly  300  can be configured so that when the contralateral guidewire  194  is advanced distally the locking portion  194   b  of the contralateral guidewire  194  may peel out of the housing  301 , thereby freeing the contralateral guidewire  194  from the locking assembly. Additionally or alternatively, the locking assembly  300  may be configured so that a release member  311  is advanced over the contralateral guidewire  194  to assist in freeing the contralateral guidewire  194  from the locking assembly  300 . 
       FIG. 18K  depicts an embodiment of the locking assembly  300  having an extended portion  464  of the contralateral branch sheath  190 . The extended portion  464  may wrap around a portion of the locking assembly  300 , thereby retaining the locking portion  194   b  of the contralateral guidewire  194  within a pocket  432  of the locking assembly  300 . The extended portion  464  may be held closed by a suture. The suture can be coupled to the contralateral branch sheath  190 . The suture can be configured to separate the extended portion  464  from the housing  301  as the contralateral branch sheath  190  is proximally withdrawn, thereby freeing the locking portion  194   b  of the contralateral guidewire  194  from the locking assembly  300 . 
       FIG. 18L  depicts an embodiment of the locking assembly  300  having a contralateral guidewire  194  that extends into the ipsilateral branch portion  54  of graft  50 . The ipsilateral limb pinches, compresses, or otherwise provides friction such that the guidewire when inadvertently advanced does not disconnect from the catheter until the ipsilateral branch portion is deployed. The contralateral guidewire  194  may extend through a bead  448 . The bead  448  may be configured to be retained within a channel  452  formed in the side of or through the housing  301  of the locking assembly  300  as described above. 
       FIG. 18M  depicts an embodiment of the locking assembly  300  having a folded portion  194   c  of the contralateral guidewire  194  that is folded over the ipsilateral branch portion  54  of the graft  50 . The folded portion  194   c  may be held against an outer surface of the ipsilateral branch portion  54  by the ipsilateral branch sheath  188 . Retraction of the ipsilateral branch sheath  188  may then free the folded portion  194   c , thereby allowing the contralateral guidewire  194  to be removed from the locking assembly  300 . 
       FIG. 18N  depicts an embodiment of the locking assembly  300  having ipsilateral locking member  468 . The ipsilateral locking member  468  can include a channel  452  configured to retain a locking portion  194   b  or bead  448  that is coupled to the contralateral guidewire  194 , as discussed above. 
       FIG. 18O  depicts an embodiment of the locking assembly  300  having a bent channel  470 . The bent channel  470  can be configured so that the locking portion  194   b  of the contralateral guidewire  194  is unable to navigate through the bent channel  470 . The locking portion  194   b  of the contralateral guidewire  194  can be decoupled for the locking assembly  300  by advancing the locking portion  194   b  proximally through the bent channel  470 . 
       FIG. 18P  depicts an embodiment of the locking assembly  300  having a ball feature  472  at the locking portion  194   b  of the contralateral guidewire  194 . The ball feature  472  can be configured to function similar to the bead  448  described above for  FIG. 18F . The ball feature  472  may be configured to be too large to pass proximally through the channel of the locking assembly  300 . The ball feature can be configured so that the locking portion  194   b  is freed from the locking assembly when the ball feature is advanced distally, thereby allowing the contralateral guidewire  194  to peel out of the channel in the locking assembly  300 . 
       FIG. 18Q  depicts an embodiment of the locking assembly  300  having a segmented locking channel  474 . The segmented locking channel  474  may include a plurality of segments  476   a, b , each having a groove  475  formed into the surface of the segment  476   a,b . The segments  476   a,b  may be joined together by a coupling member  478 . The contralateral guidewire  194  may navigate through the segmented locking channel  474 . The locking portion  194   b  of the contralateral guidewire  194  may be retained within a pocket  432  that is formed in one of the segments  476   b  of the plurality of segments  476   a,b.    
       FIG. 18R  depicts an embodiment of the locking assembly  300  having a magnetic component  480 . The magnetic component  480  can be disposed within the pocket  432  formed into the housing  301  of the locking assembly  300 . The locking portion  194   b  of the contralateral guidewire  194  may include magnetic material that causes the locking portion  194   b  to be magnetically attracted to the magnetic member  180 , thereby resisting upward forces  412  on the contralateral guidewire  194  from decoupling the locking portion  194   b  of the contralateral guidewire  194  from the locking assembly  300 . 
       FIG. 19  depicts a non-limiting exemplary embodiment of the contralateral guidewire  194 . The contralateral guidewire  194  can be configured to include multiple regions that are joined together. The contralateral guidewire  194  can have a first end  194   f  and a second end  194   g . The serial arrangement of the multiple regions of the contralateral guidewire can be varied according to the needs of the user. The serial arrangement of the regions of the contralateral guidewire  194  shown in  FIG. 19  is illustrative only and not to be taken as limiting. The contralateral guidewire  194  can include a wire core, shrink tube made of suitable material (e.g., PTFE), adhesive, alloys containing platinum, and combinations thereof. The platinum alloys can contain 90% platinum and 10% irradium, or 92% platinum and 8% tungsten. 
     The contralateral guidewire  194  may include a distal coil made of wire containing platinum, e.g., at least about 90% platinum, at least about 92% platinum, at least about 95% platinum, or at least about 99% platinum. In some embodiments, the contralateral guidewire  194  can be constructed from about 92% platinum and 8% tungsten. The distal coil may be made of wire having an outer diameter of 0.003 inches. The distal coil may have a pitch of 0.003 inches. The distal coil may have a coil outer diameter of 0.025 inches. The distal coil may have a coil length of 8.0 cm with a tolerance of 0.3 cm. 
     The contralateral guidewire  194  may include a proximal coil made of wire containing 92% platinum and 8% tungsten. The proximal coil may be made of wire having an outer diameter of 0.003 inches. The proximal coil may have a pitch of 0.003 inches. The proximal coil may have a coil outer diameter of 0.025 inches. The proximal coil may have a coil length of 15.0 cm with a tolerance of 0.3 cm. 
     A first region  194   h  (denoted as having a diameter of P in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter of 0.0160 inches with a tolerance 0.0002 inches. The first region  194   h  can have a length of 0.3 cm with a tolerance of 0.1 cm. A second region  194   i  (denoted as having a diameter of R in  FIG. 19 ) of the contralateral guidewire  194  can have a smaller diameter than the first region  194   h , e.g., less than or equal to one-half the diameter of the first region  194   h . For example, the diameter of the second region  194   i  can be about 0.0080 inches with a tolerance 0.0002 inches. The second region  194   i  can be longer than the first region  194   h . For example, the second region  194   i  can have a length of 10.4 cm with a tolerance of 0.1 cm. A third region  194   j  (denoted as having a diameter of V in  FIG. 19 ) of the contralateral guidewire  194  can have a larger diameter than the first and second regions  194   h ,  194   i . For example, the diameter of the third region  194   j  can be about 0.0174 inches with a tolerance 0.0002 inches. The third region  194   j  can be longer than the first region  194   h  and/or shorter than the second region  194   i . For example, the third region  194   j  can have a length of 1.0 cm with a tolerance of 0.1 cm. A fourth region  194   k  (denoted as having a diameter of K in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter greater than the first, second, and third regions  194   h ,  194   i ,  194   j . For example, the fourth region  194   k  can have a diameter of about 0.0300 inches with a tolerance 0.0003 inches. A fifth region  194   l  (denoted as having a diameter of H in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter that is less than the diameter of the fourth region  194   k , but greater than the diameter of the first, second, and third regions  194   h ,  194   i ,  194   j . For example, the diameter of the fifth region  194   l  can be about 0.0210 inches with a tolerance 0.0002 inches. The fifth region  194   l  can be greater than each of the preceding regions  194   h ,  194   i ,  194   j ,  194   k . For example, the fifth region  194   l  can have a length of 40.8 cm with a tolerance of 0.5 cm. A sixth region  194   m  (denoted as having a diameter of U in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter that is about the same as the diameter of the third region  194   j . For example, the diameter of the sixth region  194   m  can be about 0.0174 inches with a tolerance 0.0002 inches. The sixth region  194   m  can be shorter than the can have a length of 0.8 cm with a tolerance of 0.1 cm. A seventh region  194   n  (denoted as having a diameter of B in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter that is about the same as the second region  194   i . The diameter of the seventh region  194   n  may provide the smallest diameter of the contralateral guidewire  194 . For example, the seventh region  194   n  can have a diameter of 0.0080 inches with a tolerance 0.0002 inches. The seventh region can have a length of 5.2 cm with a tolerance of 0.1 cm. An eighth region  194   o  (denoted as having a diameter of G in  FIG. 19 ) of the contralateral guidewire  194  can have a diameter that is about the same as the diameter of the first region  194   h . For example, the eighth region  194   o  can have a diameter of about 0.0160 inches with a tolerance 0.0002 inches. The eighth region  194   o  can have a length of 0.5 cm with a tolerance of 0.1 cm. The contralateral guidewire  194  may include transition regions that soften diameter changes in the contralateral guidewire  194 . The transition regions may have a tapering angle that is formed between the longitudinal axis of the contralateral guidewire  194  and the outer wall of the transition region. The tapering angle of the transition regions can range between 10 and 60 degrees. 
     Terminology 
     While the above description has shown, described, and pointed out novel features as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made without departing from the spirit of the disclosure. Additionally, the various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure. 
     As will be recognized, certain embodiments described herein may be embodied within a form that does not provide all of the features and benefits set forth herein, as some features may be used or practiced separately from others. The scope of the inventions is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. For example, while the delivery system is described with respect to deploying a bifurcated stent in the abdominal aortic, it is further envisioned that the delivery system could be used to deliver a prosthesis having a main portion and at least one branch portion, or alternatively a prosthesis having only a straight, main branch portion, to other branched intravascular vessels (e.g., the thoracic aorta and a cardiac artery) and leave a guidewire positioned through the expanded prosthesis. 
     The term “guidewire” is to be interpreted broadly and may include, in addition to its ordinary and customary meaning to a person of ordinary skill in the art, any elongate member. Although the disclosure herein describes a locking assembly for reversibly coupling a guidewire to a delivery system, the locking assembly can also be used to reversibly couple any elongate structure to the delivery system, catheter, or otherwise. 
     As used herein, the relative terms “proximal” and “distal” shall be defined from the perspective of the delivery system. Thus, proximal refers to the direction of the control end of the delivery system and distal refers to the direction of the distal tip. 
     Note that the terms “first” and “second” branch portion can be used interchangeably and to refer to any branch vessel in the body, including but not limited to the ipsilateral vessel, the contralateral vessel, radial vessels, and subclavian vessels. Accordingly, in some embodiments, the “first” branch portion can refer to any branch portion including but not limited to the vessels set forth above. Similarly, the “second” branch portion can refer to any branch portion including but not limited to the vessels set forth below. 
     Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments. 
     The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. 
     The terms “approximately,” “about,” “generally,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than 10% of the stated amount. As another example, in certain embodiments, the terms “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees. 
     The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between” and the like includes the number recited. Numbers preceded by a term such as “about” or “approximately” include the recited numbers. For example, “approximately 2 in.” includes “2 in.” 
     Some embodiments have been described in connection with the accompanying drawings. However, it should be understood that the figures are not drawn to scale. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, it will be recognized that any methods described herein may be practiced using any device suitable for performing the recited steps. 
     For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that, achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     Moreover, while illustrative embodiments have been described herein, the scope of any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. Further, the actions of the disclosed processes and methods may be modified in any manner, including by reordering actions and/or inserting additional actions and/or deleting actions. It is intended, therefore, that the specification and examples be considered as illustrative only, with a true scope and spirit being indicated by the claims and their full scope of equivalents. 
     Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication. For example, actions such as “releasing the delivery system from the locked configuration” include “instructing release of the delivery system from the locked configuration.” 
     EXAMPLE EMBODIMENTS 
     The following example embodiments identify some possible permutations of combinations of features disclosed herein, although other permutations of combinations of features are also possible. 
     1. A locking assembly for releasably coupling a first elongate structure to a second elongate structure, the locking assembly comprising:
         a housing comprising a proximal end, a distal end, and a lateral wall portion;   a first lumen extending from the proximal end of the housing to the distal end of the housing and along a longitudinal axis of the locking assembly, the first lumen being configured to receive the first elongate structure;   a second lumen extending from the distal end of the housing, a diameter of the second lumen being less than a diameter of the first lumen, the second lumen being configured to receive the second elongate structure; and   a recessed portion extending at least partially through the housing, the recessed portion comprising at least one opening in the lateral wall portion of the housing.       

     2. The locking assembly of Embodiment 1, further comprising an elastomeric member in the recessed portion, the elastomeric member configured to retain the second elongate structure when the second elongate structure extends through the second lumen. 
     3. The locking assembly of Embodiment 2, wherein at least a portion of an outer surface of the elastomeric member is substantially flush with an outer surface of the lateral wall portion of the housing. 
     4. The locking assembly of Embodiment 2, or 3 wherein the elastomeric member comprises an opening at least partially aligned with the second lumen. 
     5. The locking assembly of Embodiment 4, wherein the opening comprises a diameter that is smaller than the diameter of the second lumen. 
     6. The locking assembly of any one of Embodiments 2 to 5, wherein the elastomeric member comprises silicone. 
     7. The locking assembly of any one of the preceding Embodiments, wherein a proximal portion of the housing is tapered. 
     8. The locking assembly of any one of the preceding Embodiments, further comprising a protruding portion extending along at least a portion of an outer periphery of a distal portion of the housing. 
     9. The locking assembly of Embodiment 8, wherein the second lumen is positioned between the first lumen and the protruding portion. 
     10. The locking assembly of any one of the preceding Embodiments, wherein the second lumen comprises a proximal portion, a distal portion, and an intermediate portion therebetween, a diameter of the intermediate portion being less than a diameter of the proximal portion and the distal portion. 
     11. A locking assembly for coupling a contralateral guidewire to an ipsilateral catheter, the locking assembly comprising:
         an anchoring portion configured to engage the ipsilateral catheter; and   an interlock portion configured to retain a distal portion of the contralateral guidewire when the contralateral guidewire is advanced or retracted unless a vertical force of at least 0.1 lbf is applied to the contralateral guidewire.       

     12. The locking assembly of Embodiment 11, wherein the interlock portion comprises a lumen, the lumen being shaped to retain the contralateral guidewire when the contralateral guidewire is retracted. 
     13. The locking assembly of Embodiment 12, wherein the lumen comprises a distal portion, a proximal portion, and an intermediate portion therebetween, a diameter of the intermediate portion being less than a diameter of the distal portion and a diameter of the proximal portion. 
     14. The locking assembly of any one of Embodiments 11 to 13, further comprising a retention member configured to frictionally retain the guidewire when the guidewire is advanced. 
     15. The locking assembly of Embodiment 14, wherein the retention member comprises an elastomeric material. 
     16. The locking assembly of Embodiment 14 or 15, wherein the retention member comprises an opening configured to receive the contralateral guidewire. 
     17. The locking assembly of any one of Embodiments 11 to 16, wherein the interlock portion is configured to release the contralateral guidewire when a force is applied to an intermediate portion of the contralateral guidewire at an angle of less than or equal to about 60 degrees from the distal portion of the guidewire in the interlock portion. 
     18. A system for reversibly securing a first elongate member to a second elongate member, the system comprising:
         a first elongate member;   a second elongate member comprising a proximal portion and a distal portion; and   a locking assembly fixed to the first elongate member, the locking assembly comprising:
           a housing comprising a proximal end and a distal end;   a lumen extending from the distal end of the housing and through at least a portion of the housing, the second lumen being configured to receive the second elongate member from a distal side of the locking assembly;   a recessed portion extending at least partially through the housing; and   an elastomeric member in the recessed portion, the elastomeric member configured to retain the distal portion of the second elongate member when the second elongate member extends through the second lumen.   
               

     19. The system of Embodiment 18, wherein the second elongate member comprises a first region and a second region, the first region having a first stiffness, the second region having a second stiffness, the first stiffness being greater than the second stiffness. 
     20. The system of Embodiment 19, wherein the first region is distal to the second legion. 
     21. The system of Embodiment 19, wherein the first region is at a distal end of the second elongate member. 
     22. The system of Embodiment 18 or 19, further comprising a sheath configured to be advanced along the second elongate member and disengage the second elongate member from the recessed portion. 
     23. The system of Embodiment 18 to 22, wherein the second elongate member is a guidewire. 
     24. The system of any one of Embodiments 18 to 23, wherein the first elongate member is a catheter. 
     25. The system of any one of Embodiments 18 to 24, wherein the second lumen comprises a proximal portion, a distal portion, and an intermediate portion therebetween, a diameter of the intermediate portion being less than a diameter of the distal portion and a diameter of the proximal portion. 
     26. The system of any one of Embodiments 18 to 25, wherein the recessed portion comprises at least one opening in a lateral wall of the housing. 
     27. The system of any one of Embodiments 18 to 26, wherein the elastomeric member comprises an opening at least partially aligned with the second lumen. 
     28. The locking assembly of Embodiment 27, wherein the opening comprises a diameter that is smaller than the diameter of the second lumen. 
     29. The locking assembly of any one of Embodiments 18 to 28, wherein the elastomeric member comprises silicone. 
     30. The locking assembly of any one of Embodiments 18 to 29, further comprising a protruding portion extending along at least a portion of an outer periphery of a distal portion of the housing. 
     31. A method for releasing a contralateral guidewire from an ipsilateral catheter, the method comprising:
         advancing a delivery system in a locked configuration, the delivery system comprising a locking assembly fixed to the ipsilateral catheter, the locking assembly comprising an interlock portion configured to retain the guidewire when the delivery system is in the locked configuration, a distal end of the guidewire being introduced into the interlock portion from a distal side of the locking assembly such that the guidewire comprises a bend when the delivery system is in the locked configuration, the bend being positioned between a proximal portion of the guidewire and the distal portion of the guidewire; and   releasing the delivery system from the locked configuration to the unlocked configuration by advancing a release catheter along the guidewire.       

     32. The method of Embodiment 31, wherein in the locked configuration, the interlock portion is configured to retain the guidewire when the guidewire is retracted. 
     33. The method of Embodiment 31 or 32, wherein before advancing the release catheter, the interlock portion is configured to retain the guidewire when the guidewire is advanced. 
     34. The method of any one of Embodiments 31 to 33, wherein releasing the delivery system comprises applying a force to the guidewire at an angle of less than or equal to about 60 degrees from a longitudinal axis of the locking assembly.