Patent Publication Number: US-2023149149-A1

Title: Bifurcated vascualr stent and methods of manufacture

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 63/263,986, filed on Nov. 12, 2021 and titled, “Bifurcated Vascular Stent and Methods of Manufacture,” and U.S. Provisional Application No. 63/380,325, filed on Oct. 20, 2022 and titled, “Bifurcated Vascular Stent and Methods of Manufacture,” both of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to endovascular prostheses. In some embodiments, the present disclosure relates to bifurcated endovascular prostheses that may access to branch arteries when implanted in a major artery, such as the aorta. Methods of manufacture and use of prostheses are also disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments disclosed herein will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. These drawings depict only typical embodiments, which will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG.  1 A  is a perspective view of an embodiment of a bifurcated endovascular prosthesis. 
         FIG.  1 B  is a perspective view of an embodiment of a bifurcated endovascular prosthesis. 
         FIG.  2    is a perspective view of an embodiment of a primary stent graft of the bifurcated endovascular prosthesis of  FIG.  1 A . 
         FIG.  2 A  is an end view of one embodiment of the primary stent graft of  FIG.  2    with a pocket having a circular cross-sectional shape. 
         FIG.  2 B  is an end view of another embodiment of the primary stent graft of  FIG.  2    with a pocket having a D-shape cross-section. 
         FIG.  3    is a longitudinal cross-sectional view of the primary stent graft of  FIG.  2   . 
         FIG.  4    is a perspective view of an embodiment of a secondary stent graft of the bifurcated endovascular prosthesis of  FIG.  1 A . 
         FIG.  5 A  is a perspective view of an embodiment of a body mandrel and pocket mandrel. 
         FIG.  5 B  is a perspective view of the pocket mandrel of  FIG.  5 A  covered with a polymeric covering. 
         FIG.  5 C  is a perspective view of the covered pocket mandrel of  FIG.  5 B  coupled to the body mandrel of  FIG.  5 B  and the body mandrel covered with a polymeric covering. 
         FIG.  5 D  is a perspective view of the covered body and pocket mandrels with an opening in the polymeric coverings. 
         FIG.  6 A  is a longitudinal cross-sectional view of the primary stent graft of  FIG.  1 A  disposed in a diseased aorta. 
         FIG.  6 B  is a longitudinal cross-sectional view of the bifurcated endovascular prosthesis of  FIG.  1 A  disposed in the diseased aorta. 
         FIG.  7    is a perspective view of another embodiment of a bifurcated endovascular prosthesis. 
         FIG.  8    is a perspective view of an embodiment of a primary stent graft of the bifurcated endovascular prosthesis of  FIG.  7   . 
         FIG.  9    is a perspective view of an embodiment of a secondary stent graft of the bifurcated endovascular prosthesis of  FIG.  7   . 
         FIG.  10    is a side view of the bifurcated endovascular prosthesis of  FIG.  7    disposed within vessels adjacent an anastomosis. 
         FIG.  11    is a perspective view of another embodiment of a bifurcated endovascular prosthesis. 
         FIG.  12 A  is a perspective view of an embodiment of a primary stent graft of the bifurcated endovascular prosthesis of  FIG.  11   . 
         FIG.  12 B  is a longitudinal cross-sectional view of the primary stent graft of  FIG.  12 A . 
         FIG.  13    is a perspective view of an embodiment of a secondary stent graft of the bifurcated endovascular prosthesis of  FIG.  11   . 
         FIG.  14 A  is a perspective view of embodiments of a body mandrel and a sleeve mandrel. 
         FIG.  14 B  is a perspective view of the sleeve mandrel of  FIG.  14 A  covered with a polymeric covering. 
         FIG.  14 C  is a perspective view of the polymeric covered sleeve mandrel of  FIG.  14 B  coupled to the body mandrel of  FIG.  14 B  and the body mandrel covered with a polymeric covering. 
         FIG.  15    is a perspective view of a wire stent winding mandrel. 
         FIG.  16 A  is a side view of the primary stent graft of  FIG.  12 A  disposed within a diseased aorta. 
         FIG.  16 B  is a side view of the bifurcated endovascular prosthesis of  FIG.  11    disposed within the diseased aorta. 
     
    
    
     DETAILED DESCRIPTION 
     Degenerative diseases of the vascular lumens of a human body, such as aneurysms and dissections, may be treated by vessel replacement, for example arterial replacement. Conventional open surgery for vessel replacement may be associated with significant risk of death or disability and may be especially dangerous for the vascular patient who typically has significant pre-existing surgical risk factors. 
     In some instances, diseased vascular lumens may be treated via minimally invasive alternatives to open vascular surgery, including processes whereby vessel replacement is performed by placement of an endovascular prosthesis via a remote access point. Such endovascular prostheses may be composed of an impervious fabric through which blood flows, preventing blood leakage though the prosthesis and directing blood flow through a portion of diseased vessel wall. The fabric may be sealed to a disease-free arterial wall above and below the diseased segment of vessel to be bypassed. Such endovascular prostheses may be utilized to repair disease of the arteries, including the thoracic and abdominal aortas as well as peripheral arteries and veins, such as the brachiocephalic veins. Tubular prostheses may be limited in their inability to repair branched vessels, as a sealed tubular construct positioned across the opening of a branch artery would prevent blood flow to the branch artery. Examples of regions of the aorta which may be affected by arterial disease that include branches include the aortic arch, from which the innominate, carotid, and subclavian arteries originate, and the proximal abdominal aorta, from which the visceral and renal arteries emerge as side branches. 
     Some embodiments of bifurcated endovascular prostheses within the scope of this disclosure may include a primary stent graft and a secondary stent graft. In some instances, bifurcated endovascular prostheses within the scope of this disclosure may be used to repair a section of the aorta adjacent the iliac arteries. In the examples that follow, and throughout this disclosure, discussion of treatment of one portion of the vasculature, such as the aorta, may be applicable to treat of other portions of the vasculature and/or other lumens of the human body, including portions of the vasculature or other lumens including a main lumen and intersecting branch lumens. For example, the bifurcated endovascular prostheses may be placed adjacent to the superior vena cava at the bifurcation of the right and left brachiocephalic veins. 
     In some embodiments, the primary stent graft includes a tubular body having a proximal portion configured to couple with healthy arterial tissue proximal to an area of the vasculature to be treated, such as a diseased portion of the aorta. The proximal portion includes a bore defined by a wall. A pocket is disposed within the bore and longitudinally coupled to a wall of the bore. The pocket includes a lumen defined by a wall with a proximal end having a proximal opening, a closed distal end, and a distal opening disposed adjacent the closed distal end. The distal opening is disposed in a wall of the proximal portion of the tubular body wherein the lumen is in communication with an exterior of the proximal portion. A leg portion extends distally from the proximal portion and includes a bore defined by a wall in fluid communication with the bore of the proximal portion. The leg portion may be configured to be disposed within one of the iliac arteries branching from the aorta. A cross-sectional area of the bore of the leg portion may be equivalent or similar to a cross-sectional area of the lumen of the pocket. The secondary stent can include a tubular body. A proximal portion of the tubular body is disposable within the lumen of the pocket through the distal opening and configured to form a fluid seal with the wall of the pocket. A distal portion of the tubular body may extend from the distal opening and into a second iliac artery. 
     A method of manufacturing an embodiment of a bifurcated endovascular prosthesis within the scope of this disclosure may include the steps of constructing a primary stent graft construct comprising: obtaining a pocket mandrel and a first body mandrel; covering the pocket mandrel with a first polymeric covering; disposing the covered pocket mandrel within a groove of the body mandrel; covering the covered pocket mandrel and the body mandrel with a second polymeric covering; forming an opening in the first polymeric covering and the second polymeric covering adjacent a distal end of the pocket mandrel; and constructing a secondary stent graft construct comprising: obtaining a second body mandrel and covering the second body mandrel with a third polymeric covering. Other steps are contemplated. 
     A method of repairing a bifurcated blood vessel may include the steps of: deploying a primary stent graft of a bifurcated endovascular prosthesis in the bifurcated blood vessel, wherein a proximal portion of the primary stent graft is deployed adjacent a diseased portion of the bifurcated blood vessel and a distal portion of the primary stent graft is deployed in a first branch vessel; and deploying a secondary stent graft of the bifurcated endovascular prosthesis, wherein a proximal portion of the secondary stent graft is disposed within a pocket of the primary stent graft and a distal portion of the secondary stent graft is disposed within a second branch vessel. Other steps are contemplated within the scope of this disclosure. Deployment and treatment of other vessels or regions of the vasculature are likewise within the scope of this disclosure. 
     Embodiments may be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be understood by one of ordinary skill in the art having the benefit of this disclosure that the components of the embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the disclosure, but is merely representative of various embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
     Various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. Many of these features may be used alone and/or in combination with one another. 
       FIGS.  1 A and  2 - 6 B  illustrate various views of an embodiment of a bifurcated endovascular prosthesis, related components, and related methods.  FIG.  1 B  illustrates a perspective view of another embodiment of a bifurcated endovascular prosthesis. The related components and related methods discussed in  FIGS.  2 - 6 B  may also apply to  FIG.  1 B .  FIGS.  7 - 10    illustrate various views of another embodiment of a bifurcated endovascular prosthesis, related components, and related methods.  FIGS.  11 - 16 B  illustrate various views of another embodiment of a bifurcated endovascular prosthesis, related components, and related methods. In certain views each bifurcated endovascular prosthesis may be coupled to, or shown with, additional components not included in every view. Further, in some views only selected components are illustrated, to provide detail into the relationship of the components. Some components may be shown in multiple views, but not discussed in connection with every view. Disclosure provided in connection with any figure is relevant and applicable to disclosure provided in connection with any other figure or embodiment. 
       FIG.  1 A  illustrates an embodiment of a bifurcated endovascular prosthesis  100 . In the illustrated embodiment, the bifurcated endovascular prosthesis  100  is partially composed of a primary stent graft  110  and a secondary stent graft  150  selectively couplable to the primary stent graft  110 . The primary stent graft  110  includes a body  111  having a proximal portion  120  and a distal portion  125 . In the illustrated embodiment of  FIG.  1 A , the body  111  may be generally cylindered in shape and have a constant diameter from the proximal portion  120  to the distal portion  125 . 
       FIG.  1 B  depicts an embodiment of a bifurcated endovascular prosthesis  100 ′ that resembles the bifurcated endovascular prosthesis  100  described above and below in certain respects. Accordingly, like features are designated with like reference numerals, with an added apostrophe. For example, the embodiment depicted in  FIG.  1 B  includes a primary stent graft  110 ′ that may, in some respects, resemble the primary stent graft  110  of  FIGS.  1 A and  2 - 6 B . Relevant disclosure set forth below regarding similarly identified features thus may not be discussed in regard to  FIG.  1 B . Moreover, specific features of bifurcated endovascular prosthesis  100 ′ and related components shown in  FIG.  1 B  may not be shown or identified by a reference numeral in the drawings or specifically discussed in the written description that follows. However, such features may clearly be the same, or substantially the same, as features depicted in other embodiments and/or described with respect to such embodiments. Accordingly, the relevant descriptions of such features apply equally to the features of the bifurcated endovascular prosthesis  100 ′ and related components depicted in  FIG.  1 B . Any suitable combination of the features, and variations of the same, described with respect to the bifurcated endovascular prosthesis  100  and related components illustrated in  FIGS.  1  and  2 - 6 B  can be employed with the bifurcated endovascular prosthesis  100 ′ and related components of  FIG.  1 B , and vice versa. This pattern of disclosure applies equally to further embodiments depicted in subsequent figures and described hereafter, wherein the leading digits may be further incremented. 
       FIG.  1 B  illustrates an embodiment of the bifurcated endovascular prosthesis  100 ′. In the illustrated embodiment, the bifurcated endovascular prosthesis  100 ′ is partially composed of the primary stent graft  110 ′ and a secondary stent graft  150 ′ selectively couplable to the primary stent graft  110 ′. The primary stent graft  110 ′ includes a body  111 ′ having a proximal portion  120 ′ and a distal portion  125 ′. In the illustrated embodiment of  FIG.  1 B , the distal portion  125 ′ of the body  111 ′ has an inward taper. The body  111 ′ transitions from a greater diameter in the proximal portion  120 ′ to a smaller diameter in the distal portion  125 ′ at a transition point  113 ′. The inward taper of the distal portion  125 ′ may allow for a guide wire (not shown) and a guide catheter (not shown) to manipulate around the body  111 ′ prior to branching secondary stent graft  150 ′. The greater diameter of the proximal portion  120 ′ creates space for the secondary stent graft  150 ′ disposed within a bore  112 ′ of the body  111 ′. 
     As illustrated, the embodiment of the bifurcated endovascular prosthesis  100  and  100 ′ may be sized or otherwise configured to repair a diseased aorta vessel proximal to a bifurcation of iliac arteries. In various other embodiments, the bifurcated endovascular prosthesis  100  and  100 ′ can be configured to repair any diseased arterial or venous vessel, including those including a bifurcation, such as a coronary artery, a carotid artery, a popliteal artery, a common femoral artery, brachiocephalic vein, etc. The bifurcated endovascular prosthesis  100  and  100 ′ may be placed in the arterial vascular system such that blood flow through the bifurcated endovascular prosthesis  100  and  100 ′ splits into two or more vessels. For example, the bifurcated endovascular prosthesis  100  and  100 ′ may be deployed at a bifurcation between an aorta vessel and the left and right iliac vessels. The bifurcated endovascular prosthesis  100  and  100 ′ may also be placed in the venous vascular system such that blood flow through the bifurcated endovascular prosthesis  100  and  100 ′ converges into a single vessel from two or more vessels. For example, the bifurcated endovascular prosthesis  100  and  100 ′ may be deployed at the bifurcation between a superior vena cava and left and right brachiocephalic vessels. As noted above, disclosure here regarding treatment of a specific region, such as the aorta, can be analogously applied to treatment of other portions of the vasculature or other lumens of the body. 
       FIG.  2    illustrates the primary stent graft  110  of the embodiment of  FIG.  1 A . The body  111  of the primary stent graft  110  may be generally cylindrical in shape having a bore  112  defined by a wall  123  extending through the proximal and distal portions  120 ,  125 , such that blood can flow from the aorta, through the bore  112 , and into an iliac artery when the bifurcated endovascular prosthesis  100  is implanted. The body  111  may be formed of a variety of materials and/or layers of materials, including biocompatible materials that are resistant to passage of blood through the wall  123 . For example, the biocompatible material may be polyethylene terephthalate, polyurethane, silicone rubber, nylon, or fluoropolymer. Other biocompatible materials are contemplated within the scope of this disclosure. A thickness of the wall  123  may range from about 0.07 millimeter to about 0.5 millimeter. 
     In some embodiments, a length of the body  111  may range from about 50 mm to about 250 mm with a length of the proximal portion  120  ranging from about 20% to about 80% of the length of the primary stent graft  110 . An outer diameter of the body  111  may range from about 18 millimeters to about 55 millimeters. In one embodiment, the body  111  may include a flared proximal end to facilitate sealing of the proximal portion  120  with a wall of the aorta and to prevent leakage of blood between the proximal portion  120  and the aorta wall. In some embodiments, the body  111  may include a cuff disposed adjacent the proximal portion  120  configured to facilitate sealing of the proximal portion  120  with the vessel wall and to prevent leakage of blood between the proximal portion  120  and the aorta wall. In other embodiments, the body  111  may include fixation features configured to prevent migration of the bifurcated endovascular prosthesis  100  relative to the aorta wall. The fixation features may include protruding barbs, sharpened protruding barbs, an adhesive, inflatable portions, strut hooks, etc. 
     As shown in  FIG.  3   , the proximal portion  120  includes a pocket  130  disposed within the bore  112  and configured to receive the secondary stent graft  150 . The pocket  130  is oriented such that it extends in a proximal direction along the wall  123  of the bore  112 . A portion of a wall  136  of the pocket  130  may be coupled to the wall  123 . The pocket  130  may be integrally formed with the wall  123  of the body  111 . The proximal portion  120  and the pocket  130  may be formed to be an integral or unibody component such that there is not a seam or joint at a junction of the body  111  and the pocket  130 . The pocket  130  includes a proximal end  131 , a distal end  132 , a proximal opening  133 , a distal opening  134 , and a lumen  135  defined by a wall  136 . The pocket  130  may have a substantially round transverse cross-sectional shape, as shown in  FIG.  2 A . In another embodiment, a transverse cross-section of the pocket  130  may include a D-shape, as shown in  FIG.  2 B . In other embodiments, the pocket  130  may include any suitable transverse cross-sectional shape, such as oval, obround, semicircular, D-shaped, etc. 
     In some embodiments, the pocket  130  may be formed of the same material as the body  111  while in other embodiments these elements may be formed of different materials. A length of the pocket  130  may range from about 5 mm to about 50 mm. A thickness of the wall  136  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. The proximal end  131  of the pocket  130  is disposed distally of a proximal end of the body  111 . The proximal opening  133  is disposed at the proximal end  131 . The distal opening  134  is disposed adjacent the distal end  132  and in the wall  123  of the body  111 . The lumen  135  extends from the proximal opening  133  to the distal opening  134 . The lumen  135  may be configured to sealingly receive the secondary stent graft  150 . A diameter of the lumen  135  may be equivalent to or smaller than an outer diameter of the secondary stent graft  150  such that an outer surface of the secondary stent graft  150  seals with an inner surface of the wall  136  of the pocket  130 . In certain embodiments, the wall  136  may be circumferentially stretched when the secondary stent graft  150  is disposed within the lumen  135 . 
     As shown in  FIG.  3   , the distal opening  134  of the pocket  130  may be disposed in the wall  123 . The distal opening  134  is in fluid communication with the lumen  135  of the pocket  130  and with an exterior environment of the primary stent graft  110 . In some embodiments, the distal opening  134  may be disposed at any location along a length of the proximal portion  120 . A diameter of the distal opening  134  may be sized to receive the secondary stent graft  150 . In other words, the distal opening  134  may be correlated to the secondary stent graft  150 , for example, the diameter of the distal opening  134  may be equivalent to or smaller than an outer diameter of the secondary stent graft  150 . The distal end  132  is closed. The distal end  132  may include an end wall  137  disposed at an angle ranging from about 30 degrees to about 90 degrees. The end wall  137  may be curved, as shown in  FIG.  3   . The distal opening  134  and the end wall  137  can be configured to allow the secondary stent graft  150  to extend radially outward from the primary stent graft  110  at an angle ranging from about zero degree to about 180 degrees. 
     As shown in  FIG.  2   , a wire scaffolding, framework, or stent such as wire stent  140  is shown to circumferentially surround the body  111 . The wire stent  140  may be configured to radially expand the body  111  from a crimped or delivery configuration to an expanded or deployed configuration. When the bifurcated endovascular prosthesis  100  is deployed within a blood vessel, the body  111  may be pressed against a wall of the blood vessel. The wire stent  140  may be formed of any suitable material such as nickel-titanium alloy, stainless steel, platinum, polymers, etc. The wire stent  140  may have a zig-zag pattern, a wave pattern, or any other suitable pattern. An area  141  of the body  111  surrounding the distal opening  134  may be void of the wire stent  140 . In the void area  141 , the zig-zag pattern may loop back on itself to prevent the wire stent  140  from crossing over the distal opening  134 . The wire stent  140  may be pre-formed or formed over the body  111 . The material, pattern, and wire diameter of the wire stent  140  may be configured to provide a chronic radially outward directed force and a resistance to a radially inward directed force. 
       FIG.  4    illustrates an embodiment of the secondary stent graft  150 . As illustrated, the secondary stent graft  150  includes a body  151  including a proximal portion  156  and a distal portion  157 . The body  151  may be generally cylindrical in shape having a bore  152  defined by a wall  153  such that blood can flow from the aorta, through the bore  152 , and into an iliac artery when the bifurcated endovascular prosthesis  100  is implanted. A cross-sectional area of the bore  152  may be substantially equivalent to a cross-sectional area of the bore  112  of the primary stent graft  110 . This configuration facilitates substantially equivalent blood flow rates through the bores  112 ,  152  such that blood flow to the iliac arteries is substantially equivalent. 
     The body  151  may be formed of a variety of materials and/or layers of materials, including biocompatible materials that are resistant to passage of blood through the wall  153 . For example, the biocompatible material may be polyethylene terephthalate, polyurethane, silicone rubber, nylon, or fluoropolymer. Other biocompatible materials are contemplated within the scope of this disclosure. A thickness of the wall  153  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. 
     In some embodiments, a length of the body  151  may range from about 20 millimeters to about 250 millimeters. An outer diameter of the body  151  may range from about 3 millimeters to about 55 millimeters. In some embodiments, the body  151  may include fixation features  159  configured to prevent migration of the secondary stent graft  150  relative to the primary stent graft  110 . For example, in one embodiment, the fixation features  159  may be disposed at a proximal end of the body  151  to couple with the proximal end  131  of the pocket  130  to prevent the secondary stent graft  150  from distal migration or distal axial movement relative to the primary stent graft  110 . In another embodiment, the fixation features  159  may be disposed at a mid-portion of the body  151  to couple with the body  111  adjacent the distal opening  134  to prevent the secondary stent graft  150  from proximal migration or proximal axial movement relative to the primary stent graft  110 . The fixation features  159  may include protruding barbs, sharpened protruding barbs, an adhesive, inflatable portions, flared portions, strut hooks, or any combination thereof, etc. In some embodiments, the pocket  130  includes the fixation features  159  to engage the secondary stent graft  150  to prevent distal and/or proximal migration or movement of the secondary stent graft  150  relative to the primary stent graft  110   
     In certain embodiments, the lumen  135  of the pocket  130  can be inwardly tapered from the proximal end  131  to the distal end  132  and the secondary stent graft  150  can be inwardly tapered along the proximal portion  156  to prevent distal migration of the secondary stent graft  150  relative to the primary stent graft  110 . In another embodiment, the body  151  may include a step transition from a larger diameter proximal portion  156  to a smaller diameter distal portion  157 . The pocket  130  may include a corresponding step transition to receive the step transition of the body  151  to prevent distal migration of the secondary stent graft  150  relative to the primary stent graft  110 . 
     A wire scaffolding, framework, or stent such as wire stent  155  is shown to circumferentially surround the body  151 . The wire stent  155  may be configured to radially expand the body  151  from a crimped or delivery configuration to an expanded or deployed configuration. When the bifurcated endovascular prosthesis  100  is deployed, the proximal portion of the body  151  may be pressed against the wall  136  of the pocket  130  and a distal portion of the body  151  may be pressed against a wall of the iliac artery. The wire stent  155  may be formed of any suitable material, such as nickel-titanium alloy, stainless steel, platinum, polymers, etc. The wire stent  155  may have a zig-zag pattern, a wave pattern, or any other suitable pattern. The wire stent  155  may be pre-formed or formed over the body  151 . The material, pattern, and wire diameter of the wire stent  155  may be configured to provide a chronic radially outward directed force and a resistance to a radially inward directed force. In some embodiments, the wire stent  155  may include one, two, three, or more lumens. 
       FIGS.  5 A- 5 D  illustrate a method of manufacturing the primary stent graft  110 .  FIG.  5 A  depicts a body forming mandrel  160  and a pocket forming mandrel  170 . The body forming mandrel  160  includes a slot or groove  161  configured to receive the pocket forming mandrel  170 . The body forming mandrel  160  is generally cylindrical in shape and formed from any suitable material, such as stainless steel, aluminum, etc. The pocket forming mandrel  170  includes a convex shaped outer surface  171 , wherein a curvature of the outer surface  171  corresponds with a curvature of an outer surface  162  of the body forming mandrel  160 . The pocket forming mandrel  170  further includes a convex shaped inner surface  172 . A cross-section of the pocket forming mandrel  170  includes an eye shape. The slot  161  includes a concave shape having a curvature to correspond to a curvature of the inner surface  172 . As illustrated, a distal end  173  of the pocket forming mandrel  170  includes a radius. In other embodiments, the distal end  173  may be angled squared off, pointed, etc. 
     As depicted in  FIG.  5 B , a polymeric covering  174  surrounds the pocket forming mandrel  170 . The covering  174  will be the wall  136  of the pocket  130  of the bifurcated endovascular prosthesis  100 , as previously described. The material of the wall  136  is previously described. The covering  174  can be applied using any suitable technique. For example, the covering  174  can be applied by wrapping strips of material around the mandrel, serially depositing material onto the mandrel, dipping the mandrel into a solvent based polymer solution, or spraying the mandrel with a solvent based polymer solution. Other application techniques are contemplated. As the arrows of  FIG.  5 B  indicate, during manufacturing, the covered pocket forming mandrel  170  may be disposed within the slot  161 . 
     As shown in  FIG.  5 C , a polymeric covering  163  is disposed around the body forming mandrel  160  and the covered pocket forming mandrel  170  that has been disposed in slot  161 . The covering  163  is configured to be the wall  123  of the body  111  of the primary stent graft  110  as previously described. The covering  163  can be applied using any suitable technique. For example, the covering  163  can be applied by wrapping strips of material around the mandrel, serially depositing material onto the mandrel, dipping the mandrel into a solvent based polymer solution, or spraying the mandrel with a solvent based polymer solution. Other application techniques are contemplated. 
     As illustrated in  FIG.  5 D , an opening  164  is formed in the covering  163 . The opening  164  is configured to be the distal opening  134  of the pocket  130  as previously described. The opening  164  can be formed using any suitable technique. For example, the opening  164  can be formed by cutting with a die, blade or laser. Other forming techniques are contemplated. In certain embodiments, the distal end  173  of the pocket forming mandrel  170  may be used as a guide or reference mark to form the opening  164 . In other embodiments, the opening  164  is formed following removal of the pocket forming mandrel  170 . 
     The wire stent  140  may be disposed over the covered body and pocket forming mandrels  160 ,  170  and oriented such that the void area  141  surrounds the opening  164 . An outer polymeric covering may be disposed over the wire stent  140 . The covered wire stent  140  and covered body and pocket forming mandrels  160 ,  170  may be sintered at about 385 degrees Centigrade to bind the coverings and the wire stent  140  together. The body and pocket forming mandrels  160 ,  170  are removed from the body  111  and the pocket  130 , respectfully. 
       FIGS.  6 A and  6 B  illustrate a method of implanting the bifurcated endovascular prosthesis  100  in a diseased blood vessel (e.g., aorta) and iliac arteries.  FIG.  6 A  shows the primary stent graft  110  of the bifurcated endovascular prosthesis  100  deployed in the aorta  180 . The primary stent graft  110  may be deployed using a delivery catheter system, wherein the primary stent graft  110  is radially compressed and disposed within the delivery catheter system. The body  111  may be radially expanded (e.g., self-expanded or balloon expanded) to compress the proximal portion  120  against a healthy tissue section of a wall of the aorta  180  proximal to a diseased section  181  of the aorta  180  such that the bifurcated endovascular prosthesis  100  may be secured in place. The diseased section  181  may be an aneurysm, a pseudoaneurysm, an aortic dissection, a stenosis, or any other type of vascular disease. The distal portion  125  may extend distally into a first iliac artery  182  and may be radially expanded to compress against a wall of the first iliac artery  182 . 
       FIG.  6 B  shows the secondary stent graft  150  deployed and coupled to the primary stent graft  110 . The secondary stent graft  150  may be deployed using a delivery catheter system, wherein the secondary stent graft  150  is radially compressed and disposed within the delivery catheter system. A proximal portion  156  is disposed within the pocket  130  and a distal portion  157  extends through the distal opening  134  and into the second iliac artery  183 . The secondary stent graft  150  may be radially expanded (e.g., self-expanded or balloon expanded) to compress the proximal portion  156  against the wall  136  of the pocket  130  and the distal portion  157  against a wall of the second iliac artery  183  to form a fluid tight seal and to secure the secondary stent graft  150  in place. When the bifurcated endovascular prosthesis  100  is fully deployed, as shown in  FIG.  6 B , blood can flow from the aorta  180 , into the primary stent graft  110 . Within the primary stent graft  110  the blood flow is divided into two flows, a first flow continues through the primary stent graft  110  and exits into the first iliac artery  182 , and the second flow enters the secondary stent graft  150 , flows through the secondary stent graft  150 , and exits into the second iliac artery  183 . The blood flows into the first and second iliac arteries  182 ,  183  can be substantially equivalent. In other embodiments, the bifurcated endovascular prosthesis  100  may include more than two lumens and the blood flow in each of the lumens may be substantially equivalent or may be different depending on a size of blood vessel the lumen is in fluid communication with. 
       FIGS.  7 - 10    depict an embodiment of a bifurcated endovascular prosthesis  200  that resembles the bifurcated endovascular prosthesis  100  described above in certain respects. Accordingly, like features are designated with like reference numerals, with the leading digit incremented to “2.” For example, the embodiment depicted in  FIGS.  7 - 10    includes a primary stent graft  210  that may, in some respects, resemble the primary stent graft  110  of  FIG.  1 A . Relevant disclosure set forth above regarding similarly identified features thus may not be repeated hereafter. Moreover, specific features of the bifurcated endovascular prosthesis  100  and related components shown in  FIGS.  1 - 6 B  may not be shown or identified by a reference numeral in the drawings or specifically discussed in the written description that follows. However, such features may clearly be the same, or substantially the same, as features depicted in other embodiments and/or described with respect to such embodiments. Accordingly, the relevant descriptions of such features apply equally to the features of the bifurcated endovascular prosthesis  200  and related components depicted in  FIGS.  7 - 10   . Any suitable combination of the features, and variations of the same, described with respect to the bifurcated endovascular prosthesis  100  and related components illustrated in  FIGS.  1 - 6 B  can be employed with the bifurcated endovascular prosthesis  200  and related components of  FIGS.  7 - 10   , and vice versa. This pattern of disclosure applies equally to further embodiments depicted in subsequent figures and described hereafter, wherein the leading digits may be further incremented. 
       FIG.  7    illustrates an embodiment of a bifurcated endovascular prosthesis  200 . In the illustrated embodiment, the bifurcated endovascular prosthesis  200  is partially composed of a primary stent graft  210  and a secondary stent graft  250  selectively coupled to the primary stent graft  210 . 
     As depicted in  FIG.  8   , the primary stent graft  210  includes a body  211  having a proximal portion  220 , a distal portion  225 , and a bore  212  extending therethrough. In some embodiments, a length of the body  211  may range from about 20 millimeters to about 250 millimeters with a length of the proximal portion  220  ranging from about 20% to about 80% of the length of the primary stent graft  210 . An outer diameter of the body  211  may range from about 3 millimeters to about 55 millimeters. In the illustrated embodiment, the proximal portion  220  includes a pocket  230  disposed within the bore  212  and configured to receive the secondary stent graft  250 . The pocket  230  includes a proximal end  231 , a distal end  232 , a proximal opening  233 , a distal opening  234 , and a lumen  235  defined by a wall  236 . A length of the pocket  230  may range from about 10% to about 90% of the length of the proximal portion  220 . A thickness of the wall  236  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. The proximal opening  233  is disposed at the proximal end  231 . The distal opening  234  is disposed adjacent the distal end  232  and in the wall  236  of the body  211 . The distal end  232  is closed. The lumen  235  extends from the proximal opening  233  to the distal opening  234 . 
     The distal end  232  may include an end wall  237  disposed at an angle ranging from about 30 degrees to about 90 degrees. The distal opening  234  and the distal end  232  can be configured to allow the secondary stent graft  250  to extend radially outward from the body  211  at an angle ranging from about 30 degrees to about 90 degrees. When outside of the body  211 , the secondary stent graft  250  may be configured to bend at an angle ranging from about zero degree to about 180 degrees. 
     A wire scaffolding, framework, or stent such as wire stent  240  is shown to circumferentially surround the body  211 . The wire stent  240  may be configured to radially expand the body  211  from a crimped or delivery configuration to an expanded or deployed configuration. An area  241  of the body  211  surrounding the distal opening  234  may be void of the wire stent  240 . In the void area  241 , a zig-zag pattern may loop back on itself to prevent the wire stent  240  from crossing over the distal opening  234 . 
       FIG.  9    illustrates an embodiment of the secondary stent graft  250 . As illustrated, the secondary stent graft  250  includes a body  251  having a proximal portion  256  and a distal portion  257 . The body  211  may be generally cylindrical in shape having a bore  252  defined by a wall  253 . A thickness of the wall  253  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. In an embodiment, a cross-sectional area of the bore  252  may be substantially equivalent to a cross-sectional area of the bore  212  of the primary stent graft  210 . This configuration facilitates substantially equivalent blood flow rates through the bores  212 ,  252 . In some embodiments, the cross-sectional area of the bore  252  may be smaller or larger than the cross-sectional area of the bore  212 , such that a blood flow rate through the bore  252  is lesser than or greater than, respectively, a blood flow rate through the bore  212 . 
     In some embodiments, a length of the body  251  may range from about 20 millimeters to about 250 millimeters. An outer diameter of the proximal portion  256  may range from about 3 millimeters to about 55 millimeters. An outer diameter of the distal portion  257  may range from about 3 millimeters to about 55 millimeters. A taper portion  258  may be disposed between the proximal portion  256  and the distal portion  257 . A wire scaffolding, framework, or stent such as wire stent  255  is shown to circumferentially surround the body  251 . The wire stent  255  may be configured to radially expand the body  251  from a crimped or delivery configuration to an expanded or deployed configuration. 
       FIG.  10    illustrates the bifurcated endovascular prosthesis  200  deployed adjacent an arteriovenous (AV) fistula  290 . The AV fistula  290  may be utilized to provide vascular access for hemodialysis treatments of patients with end stage renal disease or other kidney failure. In various embodiments, the bifurcated endovascular prosthesis  200  may be utilized to either create or repair the AV fistula  290 . As illustrated, the primary stent graft  210  is disposed within an artery  292 . The artery  292  may be any artery within the patient&#39;s body that is suitable to be anastomosed or connected to an adjacent vein to form the AV fistula  290 . For example, the artery may be a radial artery, an ulnar artery, a brachial artery, a femoral artery, etc. The primary stent graft  210  is positioned with the proximal portion  220  proximal to an anastomosis  291  of the artery  292  and a vein  293  and the distal portion  225  distal to the anastomosis  291 . The proximal portion  220  is directed upstream such that blood can flow into the proximal portion  220  and the secondary stent graft  250 . The distal opening  234  of the pocket  230  is disposed at the anastomosis  291 . The secondary stent graft  250  extends from the primary stent graft  210  through the anastomosis  291  into the vein  293 . The proximal portion  256  of the secondary stent graft  250  is disposed within the pocket  230  and the distal portion  257  is disposed in the vein  293 . In other embodiments, the primary stent graft  210  can be deployed in the artery  292  and the secondary stent graft  250  can be deployed in the vein  293  such that the secondary stent graft  250  extends through a wall of the vein  293 , through a wall of the artery  292  and into the pocket  230  to create an AV fistula. 
     When the bifurcated endovascular prosthesis  200  is deployed as shown in  FIG.  10   , blood can flow from the artery  292  proximal to the bifurcated endovascular prosthesis  200  into the bifurcated endovascular prosthesis  200  where the blood flow can be split into a first blood flow that continues through the bifurcated endovascular prosthesis  200  and into the artery  292  distal to the bifurcated endovascular prosthesis  200  and a second blood flow that flows through the secondary stent graft  250  and into the vein  293 . 
       FIG.  11    illustrates an embodiment of another bifurcated endovascular prosthesis  300 . In the illustrated embodiment, the bifurcated endovascular prosthesis  300  is partially composed of a primary stent graft  310  and a secondary stent graft  350  selectively coupled to the primary stent graft  310 . 
     As depicted in  FIGS.  12 A and  12 B , the primary stent graft  310  includes a body  311  having a proximal portion  320 , a distal portion  325 , and a bore  312  defined by a wall  323  extending therethrough. In some embodiments, a length of the body  311  may range from about 20 millimeters to about 250 millimeters with a length of the proximal portion  320  ranging from about 20% to about 80% of the length of the primary stent graft  310 . An outer diameter of the proximal portion  320  may range from about 20 millimeters to about 55 millimeters and an outer diameter of the distal portion  325  may range from about 10 millimeters to about 28 millimeters. 
     In the illustrated embodiment, the proximal portion  320  includes a sleeve  330  disposed within the bore  312  and configured to receive the secondary stent graft  350 . The sleeve  330  includes a proximal end  331 , a distal end  332 , a distal opening  334 , and a lumen  335  defined by a wall  336 . A length of the sleeve  330  may range from about 10% to about 90% of a length of the proximal portion  320 . A thickness of the wall  336  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. A portion of the wall  336  is coupled to the wall  323  of the body  311 . The distal opening  334  is disposed at the distal end  332  and in a distally facing portion  326  of the body  311 . The lumen  335  extends from the proximal end  331  to the distal opening  334 . The proximal end  331  is closed. A cross-sectional area of the lumen  335  may be substantially equivalent to a cross-sectional area of the bore  312  through the distal portion  325  of the body  311 . The sleeve  330  can be configured to collapse against the wall  323  when the primary stent graft  310  is in a crimped or delivery configuration. A wire scaffolding, framework, or stent such as wire stent  340  is shown to circumferentially surround the body  311 . The wire stent  340  may be configured to radially expand the body  311  from the crimped or delivery configuration to an expanded or deployed configuration. 
       FIG.  13    illustrates an embodiment of the secondary stent graft  350 . As illustrated, the secondary stent graft  350  includes a body  351  having a proximal portion  356  and a distal portion  357 . The body  351  may be generally cylindrical in shape having a bore  352  defined by a wall  353 . A thickness of the wall  353  may range from about 0.1 millimeter to about 0.9 millimeter and from about 0.21 millimeter to about 0.57 millimeter. In an embodiment, a cross-sectional area of the bore  352  may be substantially equivalent to a cross-sectional area of the bore  312  of the primary stent graft  310 . This configuration facilitates substantially equivalent blood flow rates through the bores  312 ,  352 . In some embodiments, the cross-sectional area of the bore  352  may be smaller or larger than the cross-sectional area of the bore  312 , such that a blood flow rate through the bore  352  is lesser than or greater than, respectively, a blood flow rate through the bore  312 . 
     In some embodiments, a length of the body  351  may range from about 30 millimeters to about 250 millimeters. An outer diameter of the body  351  may range from about 7.5 millimeters to about 25.2 millimeters wherein the body  351  may be configured to be oversized relative to the bore  312  of the primary stent graft  310 . A wire scaffolding, framework, or stent such as wire stent  355  is shown to circumferentially surround the body  351 . The wire stent  355  may be configured to radially expand the body  351  from a crimped or delivery configuration to an expanded or deployed configuration. 
       FIGS.  14 A- 14 C  illustrate a method of manufacturing the primary stent graft  310 .  FIG.  14 A  depicts a body forming mandrel  360  and a sleeve forming mandrel  370 . The body forming mandrel  360  includes a slot or groove  361  configured to receive the sleeve forming mandrel  370 . The body forming mandrel  360  is generally cylindrical in shape and formed from any suitable material, such as stainless steel, aluminum, etc. The sleeve forming mandrel  370  includes a convex shaped outer surface  371 , wherein a curvature of the outer surface  371  corresponds with a curvature of an outer surface  362  of the body forming mandrel  360 . The sleeve forming mandrel  370  further includes a convex shaped inner surface  372 . A cross-section of the sleeve forming mandrel  370  includes an eye shape. The slot  361  includes a concave shape having a curvature to correspond to a curvature of the inner surface  372 . In other embodiments, the slot  361  and the sleeve forming mandrel  370  can be of any suitable shape having a positive/negative mating relationship wherein the positive shape fits into the negative shape. A handle  375  may extend at an angle from a distal end of the sleeve forming mandrel  370 . 
     As depicted in  FIG.  14 B , a polymeric covering  374  surrounds the sleeve forming mandrel  370 . The covering  374  will be the wall  336  of the sleeve  330  of the primary stent graft  310 , as previously described. The material of the wall  336  is previously described. The covering  374  can be applied using any suitable technique. For example, the covering  374  can be applied by wrapping strips of material around the mandrel, serially depositing material onto the mandrel, dipping the mandrel into a solvent based polymer solution, or spraying the mandrel with a solvent based polymer solution. Other application techniques are contemplated. As the arrows of  FIG.  14 B  indicate, the covered sleeve forming mandrel  370  is disposed within the slot  361 . 
     As shown in  FIG.  14 C , a polymeric covering  363  is disposed around the body forming mandrel  360  and the covered sleeve forming mandrel  370  that has been disposed in slot  361 . The covering  363  is configured to be the wall  323  of the body  311  of the primary stent graft  310  as previously described. The covering  363  can be applied using any suitable technique. For example, the covering  363  can be applied by wrapping strips of material around the mandrel, serially depositing material onto the mandrel, dipping the mandrel into a solvent based polymer solution, or spraying the mandrel with a solvent based polymer solution. Other application techniques are contemplated 
     The wire stent  340  may be formed over a wire stent mandrel  345 . As illustrated in  FIG.  15   , the wire stent mandrel  345  includes a proximal portion  346 , a distal portion  347 , and a square transition  348  disposed between the proximal and distal portions  346 ,  347 . The pins  349   a ,  349   b  can be disposed in a pattern to form the shape of the wire stent  340  as previously described. A diameter of the pins  349   a  and  349   b  may be the same or different. The diameter of pins may range from about 0.38 millimeter to about 3.2 millimeters and may include any size suitable for creating a bend in the stent wire that is conducive for manufacture and durability of the finished stent graft device. The diameter of the pins  349   a ,  349   b  can determine a radius of a bend of the wire of the wire stent  340  as the wire is wound around the wire stent mandrel  345 . For example, a radius of a bend of the wire around the pins  349   a  may be larger than a radius of a bend of the wire around the pins  349   b  thereby inducing different rates of outward force between proximal and distal portions  346 ,  347 . 
     The formed wire stent  340  may be disposed over the body  311 . An outer polymeric covering may be disposed over the wire stent  340 . The covered wire stent  340  and body  311  may be sintered at about 385 degrees Centigrade to bind the outer covering, the wire stent  340 , and the body  311  together. The body forming and sleeve forming mandrels  360 ,  370  can be removed from the primary stent graft  310 . 
       FIGS.  16 A and  16 B  illustrate a method of implanting the bifurcated endovascular prosthesis  300  in a diseased blood vessel (e.g., aorta) and iliac arteries.  FIG.  16 A  shows the primary stent graft  310  of the bifurcated endovascular prosthesis  300  deployed in the aorta  380 . The primary stent graft  310  may be deployed using a delivery catheter system, wherein the primary stent graft  310  is radially compressed or crimped and disposed within the delivery catheter system. In various embodiments, the primary stent graft  310  may be deployed in any diseased arterial or venous vessel having a bifurcation, such as a coronary artery, a carotid artery, a popliteal artery, a common femoral artery, etc. When deployed, the body  311  may be radially expanded (e.g., self-expanded or balloon expanded) to compress the proximal portion  320  against a healthy tissue section of a wall of the aorta  380  proximal to a diseased section  381  of the aorta  380  such that the bifurcated endovascular prosthesis  300  may be secured in place. The diseased section  381  may be an aneurysm, a pseudoaneurysm, an aortic dissection, or any other type of vascular disease. The distal portion  325  may extend distally into a first iliac artery  382  and may be radially expanded to compress against a wall of the first iliac artery  382 . 
       FIG.  16 B  shows the secondary stent graft  350  deployed and coupled to the primary stent graft  310 . The secondary stent graft  350  may be deployed using a delivery catheter system, wherein the secondary stent graft  350  is radially compressed or crimped and disposed within the delivery catheter system. The catheter delivery system may be disposed into the sleeve  330  through the distal opening  334  and may be configured to open the closed proximal end  331  of the sleeve  330 . The proximal portion  356  is deployed within the sleeve  330  and a distal portion  357  extends through the distal opening  334  and into the second iliac artery  383 . The secondary stent graft  350  may be radially expanded (e.g., self-expanded or balloon expanded) to compress the proximal portion  356  against the wall  336  of the sleeve  330  and the distal portion  357  against a wall of the second iliac artery  383  to form a fluid tight seal and to secure the secondary stent graft  350  in place. When the bifurcated endovascular prosthesis  300  is fully deployed, as shown in  FIG.  16 B , blood can flow from the aorta  380 ; into the primary stent graft  310 ; and within the primary stent graft  310  the blood flow can be divided into two flows, a first flow continues through the primary stent graft  310  and exits into the first iliac artery  382 , and the second flow enters the secondary stent graft  350 , flows through the secondary stent graft  350 , and exits into the second iliac artery  383 . The blood flow rates into the first and second iliac arteries  382 ,  383  can be substantially equivalent. 
     Any methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. For example, a method of repairing a bifurcated blood vessel may include one or more of the following steps: deploying a primary stent graft of a bifurcated endovascular prosthesis in the bifurcated blood vessel, wherein a proximal portion of the primary stent graft is deployed adjacent a diseased portion of the bifurcated blood vessel and a distal portion of the primary stent graft is deployed in a first branch vessel; and deploying a secondary stent graft of the bifurcated endovascular prosthesis, wherein a proximal portion of the secondary stent graft is disposed within a pocket of the primary stent graft and a distal portion of the secondary stent graft is disposed within a second branch vessel. Other steps are also contemplated. 
     The phrases “coupled to” and “in communication with” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be coupled to or in communication with each other even though they are not in direct contact with each other. For example, two components may be coupled to or in communication with each other through an intermediate component. 
     The directional terms “distal” and “proximal” are given their ordinary meaning in the art. That is, the distal end of an implanted medical device means the end of the device furthest from the heart. The proximal end refers to the opposite end, or the end nearest the heart. As specifically applied to a bifurcated endovascular prosthesis, the proximal end of the prosthesis refers to the end configured for deployment nearest the heart (along the blood flow path of the vasculature) and the distal end refers to the opposite end, the end farthest from the heart. If at one or more points in a procedure a physician changes the orientation of the prosthesis, as used herein, the term “proximal end” always refers to the end configured for deployment closest to the heart when implanted. 
     References to approximations are made throughout this specification, such as by use of the term “substantially.” For each such reference, it is to be understood that, in some embodiments, the value, feature, or characteristic may be specified without approximation. For example, where qualifiers such as “about” and “substantially” are used, these terms include within their scope the qualified words in the absence of their qualifiers. For example, where the term “substantially perpendicular” is recited with respect to a feature, it is understood that in further embodiments, the feature can have a precisely perpendicular configuration. 
     The terms “a” and “an” can be described as one, but not limited to one. For example, although the disclosure may recite a body having “a pocket,” the disclosure also contemplates that the body can have two or more pockets. 
     Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. 
     Recitation in the claims of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. 
     Various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. Many of these features may be used alone and/or in combination with one another. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than those expressly recited in that claim. Rather, as the following claims reflect, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. 
     The claims following this written disclosure are hereby expressly incorporated into the present written disclosure, with each claim standing on its own as a separate embodiment. This disclosure includes all permutations of the independent claims with their dependent claims. Moreover, additional embodiments capable of derivation from the independent and dependent claims that follow are also expressly incorporated into the present written description. 
     Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent. The claims and embodiments disclosed herein are to be construed as merely illustrative and exemplary, and not a limitation of the scope of the present disclosure in any way. It will be apparent to those having ordinary skill in the art, with the aid of the present disclosure, that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the disclosure herein. In other words, various modifications and improvements of the embodiments specifically disclosed in the description above are within the scope of the appended claims. Moreover, the order of the steps or actions of the methods disclosed herein may be changed by those skilled in the art without departing from the scope of the present disclosure. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order or use of specific steps or actions may be modified. The scope of the invention is therefore defined by the following claims and their equivalents.