Patent Publication Number: US-2022218504-A1

Title: Branched Stent Grafts And Stent Graft Delivery System And Methods

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is a divisional and claims priority to U.S. patent application Ser. No. 15/146,982 entitled “Branched Stent Grafts and Stent Graft Delivery System and Method” filed on May 5, 2016 which is related and claims priority to U.S. Provisional Application Ser. No. 62/158,796 filed on May 8, 2015; the entire disclosures of which are specifically incorporated by reference herein in their entirety as if made a part of the present disclosure. 
    
    
     TECHNICAL FIELD 
     The presently disclosed subject matter relates generally to stent graft systems and more particularly to branched stent grafts and a stent graft delivery system for, and methods of, endovascular repair of aortic aneurysms, including abdominal and thoracic aortic aneurysms. 
     BACKGROUND 
     Paravisceral abdominal aortic aneurysms are complex aneurysms. Successful exclusion of paravisceral abdominal aortic aneurysms, in large part, hinges upon the ability to cannulate the visceral vessels through the main body of the device and then to deliver covered stents bridging the renal or mesenteric vessel to the stent graft. Currently, there is one Food and Drug Administration (FDA)-approved fenestrated aortic stent graft system marketed in the United States for the treatment of paravisceral abdominal aortic aneurysms. This device is custom-built for each patient based on preoperative computed tomographic studies and often takes at least three weeks to construct. Consequently, the one FDA-approved fenestrated aortic stent graft system is costly and requires a certain amount of advance planning and work. 
     Further, anatomic features, as well as design constraints of the stent grafts themselves (e.g., not placing fenestrations across device struts), limit the surgeon&#39;s capability to accurately deliver these devices. There are approaches using off-the-shelf devices for the treatment of juxtarenal/pararenal/paravisceral abdominal aortic aneurysms. However, these approaches are considered off-label and not according to the “Instructions for Use” by the various stent graft manufacturers. 
     SUMMARY 
     An aspect of the present disclosure is directed to an endovascular repair device comprising a stent graft comprising a main body section, with the main body section having an outer wall, and with said outer wall having at least one fenestration; and at least one branch in fixed communication with the fenestration, with said branch configured to extend a predetermined distance from the main body section, said branch having a proximate end and a distal end, said proximal end in communication with the fenestration. 
     In a further aspect, the main body is substantially cylindrical and substantially hollow. 
     In yet another aspect the stent graft is a branched stent graft. 
     In a still further aspect, the stent graft is a branched bifurcated stent graft. 
     In a further aspect, the stent graft is a covered stent graft. 
     In yet another aspect, the branch is substantially frustoconical in shape, with the proximal end having a proximal end opening diameter that is greater than a distal end opening diameter. 
     In another aspect, the branch extends inward from the outer wall of the main body and into the main body for a predetermined distance. 
     In yet another aspect, the branch extends outward from the outer wall of the main body and outside of the main body for a predetermined distance. 
     In another aspect, the branch substantially conforms to the main body profile. 
     In still another aspect, the device further comprises at least one secondary stent graft dimensioned to pass into the fenestration and into the branch that is in fixed communication with the fenestration. 
     In yet another aspect, the device is configured to be implanted in a body as an abdominal or a thoracic stent graft. 
     In another aspect, the present disclosure is directed to a kit comprising a stent graft comprising a main body section, with the main body section having an outer wall, and with the outer wall having at least one fenestration and at least one branch in communication with the fenestration, and with the branch configured to extend a predetermined distance from the main body section, with the branch having a proximate end and a distal end, and with the proximal end in communication with the fenestration; a primary stent graft sheath configured to accommodate a primary guide wire passing through the primary stent graft sheath; and at least one secondary stent graft sheath configured to accommodate at least one secondary guide wire passing through said secondary stent graft sheath. 
     A further aspect of the present disclosure is directed to a method for deploying a stent graft into a body comprising introducing a stent graft into a body, with the stent graft comprising a main body section, and with the main body section having an outer wall, with the outer wall having at least one fenestration and at least one branch in communication with the fenestration, with the branch configured to extend a predetermined distance from the main body section, and with the branch having a proximate end and a distal end, with the proximal end in communication with the fenestration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus described the presently disclosed subject matter in general terms, reference will now be made to the accompanying Drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  illustrates perspective views of two examples of known abdominal stent grafts (Prior Art); 
         FIG. 2  illustrates a perspective front view and a perspective side view of a branched aorto-uni-iliac (AUI) stent graft, which is one example of the presently disclosed branched abdominal stent grafts that comprise one or more internal branches; 
         FIG. 3  shows more details of the internal branch of the presently disclosed branched abdominal stent grafts; 
         FIG. 4  illustrates a top down view of the distal end of the AUI stent graft shown in  FIG. 2  and shows an example of an internal branch; 
         FIG. 5  illustrates a side view of the distal end of the branched bifurcated stent graft shown in  FIG. 2  and shows an example of a fenestration for mating to the internal branch; 
         FIG. 6  illustrates a perspective front view and a perspective side view of a branched bifurcated stent graft, which is another example of the presently disclosed branched abdominal stent grafts that comprise one or more internal branches; 
         FIG. 7  illustrates a side view of an example of the presently disclosed stent graft delivery system for deploying the presently disclosed branched abdominal stent grafts for the endovascular repair of abdominal and/or thoracic aortic aneurysms; 
         FIG. 8  illustrates a side view of the stent graft delivery system shown in  FIG. 7  that further comprises a steering mechanism; 
         FIG. 9  illustrates a side view of an example of the branched bifurcated stent graft that comprises three internal branches; 
         FIG. 10  illustrates perspective views of a thoracic stent graft and an example of an internal branch that conforms to the profile of the main body thereof; 
         FIG. 11  illustrates various views of the thoracic stent graft of  FIG. 10  that comprises multiple internal branches and showing the relation of the internal branches one to another; 
         FIG. 12  shows a process of using the branched bifurcated stent graft to deploy stent grafts into the arch branches of the proximal thoracic aorta; 
         FIG. 13  illustrates a flow diagram of an example of a method of using the presently disclosed stent graft delivery system, according to a minimum configuration of the disclosure; 
         FIG. 14  illustrates a flow diagram of an example of a method of using the presently disclosed stent graft delivery system for deploying the presently disclosed branched abdominal stent grafts for the endovascular repair of abdominal and/or thoracic aortic aneurysms; 
         FIG. 15  illustrates a perspective view of an example of a branched bifurcated stent graft that comprises one or more external branches; and 
         FIG. 16  shows the branched bifurcated stent graft of  FIG. 15  when deployed. 
     
    
    
     DETAILED DESCRIPTION 
     The presently disclosed subject matter now will be described more fully hereinafter with reference to the accompanying Drawings, in which some, but not all embodiments of the presently disclosed subject matter are shown. Like numbers refer to like elements throughout. The presently disclosed subject matter may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Indeed, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated Drawings. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. 
     In some embodiments, the presently disclosed subject matter provides branched stent grafts and a stent graft delivery system for, and methods of, endovascular repair of aortic aneurysms including abdominal and thoracic aortic aneurysms. Embodiments of the branched stent grafts include, but are not limited to, branched aorto-uni-iliac (AUI) stent grafts, branched bifurcated stent grafts, and branched thoracic stent grafts. 
     The presently disclosed branched stent grafts and stent graft delivery system and methods enable the surgeon to deliver a stent graft to exclude a juxtarenal/pararenal abdominal aortic aneurysm deemed appropriate for treatment by the treating physician. Features of the stent graft delivery system include, for example, (1) a multi-functional sheath through which the branched stent grafts can be delivered into the correct anatomic position, (2) bendability via a steering mechanism at the handle that aids with precise positioning, and (3) the capacity to deliver one or more smaller sheaths for the cannulation of renal arteries and the subsequent delivery of covered stents. 
     In some embodiments, the branched stent grafts comprise one or more retrograde internal branches. The internal branches are flared with a larger diameter as they meet the main body of the branched stent graft to provide greater freedom to select renal arteries of a variety of anatomic configurations. The retrograde-facing branches are prewired to enable expedient cannulation of arteries. 
     In other embodiments, the branched stent grafts comprise one or more external branches. Likewise, the external branches are prewired to enable expedient cannulation of arteries. 
     The stent graft delivery system comprises a larger directional sheath for positioning the branched stent grafts and one or more smaller sheaths for the delivery of covered stents for the complete exclusion of juxtarenal/pararenal abdominal aortic aneurysms. Each of these smaller sheaths (i.e., 7 French) consists of a dilator tip which is a shaped 5 to 8 millimeter compliant balloon that, when inflated, assists with the tracking and deliverability of covered stents into the renal artery. Additionally, these smaller sheaths are delivered via a larger stent graft sheath (i.e., 18 to 20 French). 
     The presently disclosed stent graft delivery system and methods provide a means to deliver a branched stent graft that has internal retrograde branches or external branches, which are prewired for the expedient cannulation and delivery of covered stents to one or more arteries, thereby creating a reliable proximal seal for the exclusion of juxtarenal/pararenal abdominal aortic aneurysms. The directional sheath of the main body of the branched stent graft affords accurate stent graft delivery due to its capacity to conform to the tortuosity of the native aortic neck via a control handle at the base of the sheath, a characteristic not currently a property of stent grafts currently available. Over the wires that already cannulate the retrograde internal branches (i.e., prewired) or external branches, the smaller sheaths with compliant balloon dilator tips are introduced through the stent graft sheath via a silicone ring also located at its base. Therefore, using the presently disclosed stent graft delivery system and methods for the endovascular repair of a juxtarenal/pararenal abdominal aortic aneurysm, the branched stent grafts may be delivered through single femoral access, also not currently available in the current United States market. 
       FIG. 1  shows perspective views of two examples of conventional abdominal stent grafts. For example,  FIG. 1  shows a stent graft  100 , which can be, for example, a standard tubular-shaped aorto-uni-iliac (AUI) stent graft.  FIG. 1  also shows a bifurcated stent graft  110 , which can be a standard bifurcated stent graft that includes, for example, a main body  112 , a first limb (or leg)  114 , and a second limb (or leg)  116 . Namely, first limb  114  and second limb  116  extend from the proximal end of main body  112 , wherein first limb  114  is longer than second limb  116  and second limb  116  is designed to receive a stent graft extension  120 . 
     Generally, a stent graft is a synthetic fabric tube (graft) supported by a metal scaffold (stent). In these examples, stent graft  100  and bifurcated stent graft  110  are “covered” stents, meaning that stent graft  100  and bifurcated stent graft  110  are formed of tubular metal webs covered by woven polyester material. 
     A drawback of conventional abdominal stent grafts, such as stent graft  100  and bifurcated stent graft  110 , is that they must be custom-built for each patient based on preoperative computed tomographic studies, a time-consuming and costly process. Further, anatomic features, as well as design constraints of the conventional abdominal stent grafts themselves (e.g., not placing fenestrations across device struts), limit the surgeon&#39;s capability to accurately deliver these devices. 
       FIG. 2  is a perspective front view and a perspective side view of a branched main body stent graft  200 , which is one example of the presently disclosed branched abdominal stent grafts that comprise one or more internal branches. In this example, branched main body stent graft  200  comprises a main body  210 . Main body  210  is a flexible tubular-shaped stent, which is a tubular metal web covered by a woven polyester sleeve. Accordingly, branched main body stent graft  200  is a covered stent. Main body  210  of branched AUI stent graft  200  has a distal end  212  and a proximal end  214 . Branched main body stent graft  200  comprises at least one internal branch  220  inside main body  210 . In the example shown in  FIG. 2 , branched main body stent graft  200  comprises two internal branches  220 . However, this is exemplary only. Branched main body stent graft  200  can comprise any number of internal branches  220 . 
     Each of the internal branches  220  is a flexible tubular-shaped member constructed, for example, of a nitinol skeleton covered with an expanded polytetrafluoroethylene covered stent. A distal end  222  of internal branch  220  is mated to or otherwise coupled to a fenestration or opening (see  FIG. 4  and  FIG. 5 ) in the wall of main body  210  of branched main body stent graft  200 . A proximal end  224  of internal branch  220  is free hanging inside main body  210 . 
     Each of the internal branches  220  is tapered from distal end  222  to proximal end  224 . Namely, distal end  222  has a larger diameter than proximal end  224 . That is, distal end  222  is a flared end of internal branch  220 . For example,  FIG. 3  shows more details of an internal branch  220  of the presently disclosed branched abdominal stent grafts, such as branched main body stent graft  200 . Internal branch  220  has an overall length L. Distal end  222  of internal branch  220  has a diameter d 1  and proximal end  224  has a diameter d 2 . In one example, the length L of internal branch  120  can be from about 40 mm to about 50 mm. To achieve the taper, the diameter d 1  of distal end  222  can be about twice the diameter d 2  of proximal end  224 . In one example, the diameter d 1  of distal end  222  is from 10 mm to about 12 mm, while the diameter d 2  of proximal end  224  is from about 5 mm to about 6 mm. Each internal branch  220  can be marked, for example, with a gold marker in the form of a “P” (not shown) to aid with accurate positioning of the internal branch  220  in relation to the target visceral artery. 
       FIG. 4  and  FIG. 5  are a top down view and side view, respectively, of distal end  222  of branched main body stent graft  200  shown in  FIG. 2  and shows yet more details of an example of internal branch  220 . In particular,  FIG. 4  and  FIG. 5  shows distal end  222  of internal branch  220  mated to or otherwise coupled to a fenestration or opening  230  in the wall of main body  210  of branched main body stent graft  200 . For example, distal end  222  of internal branch  220  is aligned with fenestration or opening  230  and then sutured, woven, or adhered to the wall of main body  210  in the area around fenestration or opening  230 . 
       FIG. 2  additionally shows a guide wire  250  of an endoscopy system (not shown) can run through main body  210  of branched main body stent graft  200 . Namely, guide wire  250  enters proximal end  214  and exits distal end  212  of main body  210 . In similar fashion, another guide wire  255  of an endoscopy system (not shown) can run through internal branch  220  inside main body  210  of branched main body stent graft  200 . Namely, guide wire  255  enters proximal end  224  and exits distal end  222  of internal branch  220 . Guide wire  250  running through main body  210  can be a larger diameter wire than guide wire  255  running through internal branch  220 . For example, guide wire  250  can be the guide wire in an 18 to 20 French stent graft sheath, while guide wire  255  can be the guide wire in a 7 French stent graft sheath. 
       FIG. 6  shows a perspective front view and a perspective side view of a branched bifurcated stent graft  600 , which is another example of the presently disclosed branched abdominal stent grafts that comprise one or more internal branches. Namely, branched bifurcated stent graft  600  is a bifurcated stent graft that comprises one or more internal branches  220 . 
     In this example, branched bifurcated stent graft  600  includes a main body  610 , a first limb (or leg)  612 , and a second limb (or leg)  614 . Namely, first limb  612  and second limb  614  extend from the proximal end of main body  610 , wherein first limb  612  is longer than second limb  614  and second limb  614  is designed to receive a stent graft extension (not shown). Namely, a stent graft extension (e.g., proximal extension thoracic stent graft, not shown) is provided with branched bifurcated stent graft  600  for connecting to second limb  614 . 
     Main body  610 , first limb  612 , and second limb  614  are flexible tubular-shaped members, each of which is a tubular metal web covered by a woven polyester sleeve. Accordingly, branched bifurcated stent graft  600  is a covered stent. Main body  610  has a distal end  616 . First limb  612  has a proximal end  618 . Second limb  614  has a proximal end  620 . 
     Branched bifurcated stent graft  600  comprises at least one internal branch  220  inside main body  610 , wherein internal branch  220  is the internal branch described with reference to branched main body stent graft  200  shown in  FIG. 2  through  FIG. 5 . In the example shown in  FIG. 6 , branched bifurcated stent graft  600  comprises one internal branch  220 . However, this is exemplary only. Branched bifurcated stent graft  600  can comprise any number of internal branches  220 . 
     The use of branched AUI stent graft  200  and/or branched bifurcated stent graft  600  can be briefly summarized as follows. First, branched AUI stent graft  200  and/or branched bifurcated stent graft  600  is deployed from the groin into, for example, the proximal descending thoracic aorta. Then, the one or more internal branches  220  are used to deploy smaller renal stent grafts (not shown) from the groin into the arch branches of the thoracic aorta (see  FIG. 12 ). For example, using an internal branch  220 , the renal artery can be cannulated first with a guide wire, then a small stent graft sheath, and then a small renal stent graft. 
     A stent graft delivery system for deploying the presently disclosed branched abdominal stent grafts, such as branched AUI stent graft  200  and branched bifurcated stent graft  600 , is described herein below with reference to  FIG. 7  and  FIG. 8 . 
       FIG. 7  shows a side view of an example of the presently disclosed stent graft delivery system  700  for deploying the presently disclosed branched abdominal stent grafts, such as branched AUI stent graft  200  and branched bifurcated stent graft  600 , for the endovascular repair of abdominal and/or thoracic aortic aneurysms. 
     Stent graft delivery system  700  comprises a primary stent graft sheath  710 . Primary stent graft sheath  710  is the directional mechanism of stent graft delivery system  700 . 
     A guide wire  712  runs through primary stent graft sheath  710 . A top cap  714  is at the distal end of guide wire  712 . Top cap  714  is, for example, a bullet-shaped plastic cap. Primary stent graft sheath  710  is the directional sheath and largest sheath of stent graft delivery system  700 . Primary stent graft sheath  710  can be, for example, an 18 to 20 French stent graft sheath. In one example, primary stent graft sheath  710  is constructed of nitinol-reinforced hydrophilic pliable plastic measuring about 50 cm long and delivered over any commercially available 0.035″ wire, which is guide wire  712 . 
     Primary stent graft sheath  710  encompasses a center shaft  716  through which other smaller sheaths may be introduced (e.g., stent graft sheaths  720 ). Center shaft  716  is a length of hollow flexible tubing, such as plastic or silicone tubing. In one example, the diameter of center shaft  716  is about 9.0 millimeters. One or more openings  718  are provided in the sides of center shaft  716  and near the distal end thereof. 
     Branched AUI stent graft  200  or branched bifurcated stent graft  600  is provided in relation to primary stent graft sheath  710  and center shaft  716 . For example,  FIG. 7  shows primary stent graft sheath  710  running through center shaft  716  and then through first limb  612  and main body  610  of branched bifurcated stent graft  600 . In this example, branched bifurcated stent graft  600  comprises two internal branches  220 . Primary stent graft sheath  710  may be sutured to the inner wall of branched bifurcated stent graft  600 . 
     In this example, because branched bifurcated stent graft  600  comprises two internal branches  220 , stent graft delivery system  700  further comprises two secondary stent graft sheaths  720  (e.g., secondary stent graft sheaths  720   a ,  720   b ). Each of the secondary stent graft sheaths  720  is used for visceral artery covered stent delivery. Secondary stent graft sheaths  720  are small sheaths compared to primary stent graft sheath  710 . Secondary stent graft sheaths  720  can be, for example, 7 French stent graft sheaths constructed of hydrophiliac pliable plastic and measuring about 50 cm in length and reinforced with a nitinol skeleton. 
     Each of the secondary stent graft sheaths  720  has a guide wire  722  running therethrough. For example, a guide wire  722   a  for secondary stent graft sheath  720   a  and a guide wire  722   b  for secondary stent graft sheath  720   b . The diameter of guide wire  722  can be, for example, about 0.035 inches or about 0.018 inches. Further, each of the secondary stent graft sheaths  720  may contain a 5 to 8 French compliant balloon dilator tip for the delivery of renal artery covered stents. In one example, the balloon dilator tip comprises a pre-formed 5-8 mm balloon (not shown) that is about 3-4 cm long, wherein the balloon may be guided into the aortic arch branch. The balloon may add stability to the system when delivering the renal stent grafts. This dilator may be advanced distal to the sheath itself to enable the inflated balloon located within a visceral artery to act as an anchor for the advancement of the sheath within the arterial ostium. The balloon can then be deflated and removed over the wire, leaving the sheath in its desired location. This component promotes trackability of the sheath into a visceral vessel in difficult anatomic scenarios as well as reduces the number of catheter/sheath exchanges, contributing to the efficiency of the overall operation. 
     Further, each of the secondary stent graft sheaths  720  has a standard hemostatic valve  724  at the proximal end thereof. For example, a hemostatic valve  724   a  for secondary stent graft sheath  720   a  and a hemostatic valve  724   b  for secondary stent graft sheath  720   b.    
     In this example, secondary stent graft sheath  720   a  and guide wire  722   a  enter the proximal end of center shaft  716 . Secondary stent graft sheath  720   a  and guide wire  722   a  run through center shaft  716  and then exit the side of center shaft  716  via one of the openings  718 . Then, secondary stent graft sheath  720   a  and guide wire  722   a  enter the proximal end of second limb  614  of branched bifurcated stent graft  600 . Secondary stent graft sheath  720   a  and guide wire  722   a  run through second limb  614  of branched bifurcated stent graft  600  and then enter proximal end  224  of the first internal branch  220 . Then, secondary stent graft sheath  720   a  and guide wire  722   a  exit the distal end  222  of the first internal branch  220  and exit the side of branched bifurcated stent graft  600  via its corresponding fenestration or opening  230 . 
     In like manner, secondary stent graft sheath  720   b  and guide wire  722   b  enter the proximal end of center shaft  716 . Secondary stent graft sheath  720   b  and guide wire  722   b  run through center shaft  716  and then exit the side of center shaft  716  via one of the openings  718 . Secondary stent graft sheath  720   b  and guide wire  722   b  then enter the proximal end of first limb  612  of branched bifurcated stent graft  600 . Secondary stent graft sheath  720   b  and guide wire  722   b  run through first limb  612  of branched bifurcated stent graft  600  and then enter proximal end  224  of the second internal branch  220 . Then, secondary stent graft sheath  720   b  and guide wire  722   b  exit the distal end  222  of the second internal branch  220  and exit the side of branched bifurcated stent graft  600  via its corresponding fenestration or opening  230 . 
     Referring now to  FIG. 8  shows a side view of stent graft delivery system  700  shown in  FIG. 7  that further comprises a steering mechanism. For example, the steering mechanism comprises a handle  730  and two strings  732 . One end of the pair of strings  732  is coupled to handle  730 . The pair of strings  732  are integrated into primary stent graft sheath  710 . The opposite end of the pair of strings  732  is coupled to the distal end of primary stent graft sheath  710 . Namely, about 5 cm centimeters from the distal end of the inner shaft of primary stent graft sheath  710 , two 0.018″ strings (e.g., two strings  732 ) attach at the three and nine o&#39;clock positions and travel along the inner shaft through the outer sheath and attach at the same positions to a two inch-long handle  730 . According to one non-limiting aspect of the present disclosure, for example, with clockwise revolution of the hand, the stent graft and distal inner shaft of stent graft delivery system  700  tilts to the left; with counter-clockwise revolution, the stent graft and distal inner shaft of stent graft delivery system  700  tilt to the right. 
     Further, a pull control  734  may be provided on center shaft  716  to unwrap branched bifurcated stent graft  600 . 
     In one embodiment, a silicone ring (not shown) may be provided just below pull control  734  and proximal to handle  730 . Catheters and sheaths may be introduced through this ring wherein the silicone keeps the sheaths hemostatic as it seals around them. Sheaths and catheters that pass through the silicone ring enter the main common channel of the stent graft delivery system  700 . 
     According to an aspect of the present disclosure, the operation of stent graft delivery system  700  can be briefly summarized as follows. First, primary stent graft sheath  710  is used to deploy the presently disclosed branched abdominal stent grafts, such as branched main body stent graft  200  ( FIG. 2 ) and/or branched bifurcated stent graft  600 , into and from the groin, then into, for example, the proximal descending thoracic aorta or juxtarenal abdominal aorta. Then, the secondary stent graft sheaths  720  are used to deploy smaller renal stent grafts (not shown) to and through the one or more internal branches  220  and then into the arch branches of the thoracic aorta (see  FIG. 12 ). For example, using an internal branch  220 , the renal artery can be cannulated first with guide wire  722 , then the small secondary stent graft sheath  720 , and then the small renal stent graft (not shown). The flared distal end  222  of the internal branches  220  assists in the selectivity of the aortic arch branches. For example, the flared distal end  222  of the internal branches  220  provides greater freedom to select renal arteries of a variety of anatomic configurations as compared with conventional stent graft delivery systems. 
     According to an aspect of the present disclosure, stent graft delivery system  700  is provided as a kit packaged with branched main body stent graft  200  or branched bifurcated stent graft  600  and with the one or more internal branches  220  of branched main body stent graft  200  or branched bifurcated stent graft  600  prewired with secondary stent graft sheaths  720 . For example,  FIG. 9  shows a side view of an example of branched AUI stent graft  200  that comprises three internal branches  220 , which are prewired with three respective guide wires  722 .  FIG. 9  also shows that the side of branched main body stent graft  200  that has the three internal branches  220  may be contoured (e.g., contoured portion  226 ). Contoured portion  226  is provided to assist with packing the branched main body stent graft  200  and to assist arch vessel selection using catheter manipulation. Further,  FIG. 9  shows that branched main body stent graft  200  may include a barb  228  on the side of main body  210  at each internal branch  220 . Barbs  228  can be flaps of fabric that help form a seal between the small renal stent grafts and branched main body stent graft  200 . In similar fashion, branched bifurcated stent graft  600  may include a contoured portion and barbs. 
     The use of “branches” is not limited to abdominal stent grafts (e.g., bifurcated stent grafts and AUI stent grafts), rather the use of “branches” can be also extended to thoracic components, such as thoracic stent graphs. More details of examples of thoracic stent graphs that include branches are described hereinbelow with reference to  FIG. 10  and  FIG. 11 . 
       FIG. 10  shows perspective views of a branched thoracic stent graft  900  and an example of an internal branch  930  that substantially conforms to the profile of the main body thereof. For example, branched thoracic stent graft  900  includes a main body  910  (e.g., a tubular body) that has a proximal end  912  and a distal end  914 . In this example, internal branch  930  runs in the same direction as main body  910  and is maintained in a substantially fixed position just under the surface of main body  910 . Internal branch  930  has a proximal end  932  and a distal end  934 . Proximal end  932  is accessible from inside main body  910 , while distal end  934  is configured to emerge from main body  910  within a contoured portion  916  thereof. When in use, a smaller stent graft (or bridging stent graft)  940  can be deployed from internal branch  930 . 
     In one example, internal branch  930  has a diameter of from about 8 mm to about 10 mm. Accordingly, the depth of contoured portion  916  can also be from about 8 mm to about 10 mm in diameter. Further, the portion at proximal end  912  of main body  910  that is outside contoured portion  916  can be a proximal seal zone  918 . In one example, proximal seal zone  918  is about 30 mm long. The portion at distal end  914  of main body  910  that is outside contoured portion  916  can be a distal seal zone  920 . In one example, distal seal zone  920  is about 20 mm long. However, the seal zones can generally range from about 15 cm to about 30 cm. 
       FIG. 11  shows a side view, top view, and end view of an example of branched thoracic stent graft  900  that comprises multiple internal branches  930   a ,  930   b ,  930   c  and showing the relation of the internal branches  930   a ,  930   b ,  930   c  one to another. In this example, branched thoracic stent graft  900  includes three internal branches  930   a ,  930   b ,  930   c . Branched thoracic stent graft  900  can be prewired and deployed using, for example, stent graft delivery system  700  (see  FIG. 7  and  FIG. 8 ). 
     The end view (proximal end) of branched thoracic stent graft  900  shows the predetermined spacing/positions of internal branches  930   a ,  930   b ,  930   c  around the circumference of main body  910 , while the side and top views are intended to show an exemplary staggered relation of the internal branches  930   a ,  930   b ,  930   c . For example, in the end view, if internal branch  930   b  is at 12 o&#39;clock, then internal branch  930   c  is at about 10 o&#39;clock, and internal branch  930   a  is at about 2 o&#39;clock. 
     According to one aspect, as shown, the distal ends of internal branches  930   a ,  930   b ,  930   c  all emerge from contoured portion  916  of main body  910 . In this example, internal branch  930   a  is a certain length, internal branch  930   b  is a slightly shorter length than internal branch  930   a , and internal branch  930   c  is a slightly shorter length than internal branch  930   c . In one example, the overall length of main body  910  of branched thoracic stent graft  900  can be from about 12 cm to about 20 cm. 
     As shown in  FIG. 11 , branched thoracic stent graft  900  is a partially constrained main body thoracic stent graft with internal branches  930   a ,  930   b ,  930   c  that are arranged in a predetermined staggered fashion within this constrained portion (e.g., within contoured portion  916 ). This enables a lower profile device with less graft material required to be packaged, thereby increasing the ability of the surgeon to deliver the stent graft with fewer access site complications. Positioning internal branches  930   a ,  930   b ,  930   c  within the constrained portion (e.g., within contoured portion  916 ) of main body  910 , enables more room within the blood vessel to cannulate or select the main branches that come off the aorta that are being preserved with the bridging stent grafts (e.g., bridging stent grafts  940 ). 
       FIG. 12  is a side view showing a process of using branched main body stent graft  200  of  FIG. 2 , wherein three bridging stent grafts  940  are fully deployed to predetermined locations into the three thoracic aortic branches  1010  of the proximal descending thoracic aorta  1200  by use of branched main body stent graft  200 . In  FIG. 12 , whereas the larger primary stent graft sheath  710  is used to deploy branched main body stent graft  200 , the smaller secondary stent graft sheaths  720  are used to deploy the bridging stent grafts  940  through the internal branches  220 . 
       FIG. 13  is a flow diagram of an example of a method of using the presently disclosed stent graft delivery system  700  to deploy the presently disclosed branched stent grafts, according to a minimum configuration of the disclosure. Method  1300  may include, but is not limited to, the following steps. 
     At a step  1310 , stent graft delivery system  700  that includes a certain type of branched abdominal stent graft is provided. In one example, stent graft delivery system  700  is packaged with a branched main body stent graft  200  and provided to the surgeon. In another example, stent graft delivery system  700  is packaged with a branched bifurcated stent graft  600  and provided to the surgeon. In another example, stent graft delivery system  700  is packaged with a branched thoracic stent graft  900  and provided to the surgeon. 
     At a step  1312 , primary stent graft sheath  710  of stent graft delivery system  700  is used to deploy the presently disclosed branched abdominal stent graft, such as branched main body stent graft  200 , branched bifurcated stent graft  600 , or branched thoracic stent graft  900  from the groin into, for example, the proximal descending thoracic aorta or juxtarenal abdominal aorta, respectively. 
     At a step  1314 , the secondary stent graft sheaths  720  are used to deploy smaller renal stent grafts to and through the one or more internal branches  220  and then into the arch branches of the thoracic aorta (see  FIG. 12 ). For example, using an internal branch  220 , the renal artery can be cannulated first with guide wire  722 , then the small secondary stent graft sheath  720 , and then the small renal stent graft (not shown). The flared distal end  222  of the internal branches  220  assists in the selectivity of the aortic arch branches. Further, in the case of branched bifurcated stent graft  600 , the stent graft extension (e.g., proximal extension thoracic stent graft, not shown) is deployed and connected to second limb  614 . 
       FIG. 14  is a flow diagram of an example of a method  1400  of using the presently disclosed stent graft delivery system  700  for deploying the presently disclosed branched stent grafts for the endovascular repair of abdominal and/or thoracic aortic aneurysms. By way of example, branched bifurcated stent graft  600  of  FIG. 6  is deployed using method  1400 . Method  1400  may include, but is not limited to, the following steps. 
     At a step  1410 , using primary stent graft sheath  710  of stent graft delivery system  700 , the surgeon introduces branched bifurcated stent graft  600  via the common femoral artery access, either percutaneously or via open arterial exposure. 
     At a step  1412 , branched bifurcated stent graft  600  is positioned accurately to a predetermined location using the direction-bearing handle  730 , based upon the tortuosity of the native aorta at the level of the superior mesenteric artery and one or both renal arteries, which is determined either by preoperative mapping based upon computed tomographic angiography imaging and/or aortography. Handle  730  translates movement from the surgeon into precise and predetermined movements of primary stent graft sheath  710  at the level of the branched abdominal stent graft (e.g., branched bifurcated stent graft  600 ). 
     At a step  1414 , main body  610  of branched bifurcated stent graft  600  is unsheathed, partially deploying branched bifurcated stent graft  600  and exposing the retrograde-facing internal branches  220  that will be used to assist with preservation of renal artery perfusion. 
     At a step  1416 , over the exemplary 0.018″ guide wire  722  that, according to one aspect of the disclosure are prepackaged with stent graft delivery system  700  and exiting though center shaft  716  located proximal to the directional handle  730 , the surgeon advances the one or more secondary stent graft sheaths  720  having a balloon dilator up through center shaft  716  into the one or more corresponding internal branches  220 . The flared ends of internal branches  220  provides the surgeon enough working room to cannulate each renal artery, either with the prepackaged wire  722  and balloon tip dilator or a commercially available catheter followed by the secondary stent graft sheath  720 . 
     At a step  1418 , once the surgeon tracks the balloon-tipped dilator into the renal artery and inflates the compliant balloon, the secondary stent graft sheath  720  may be tracked into the proximal ostium of the artery in preparation for delivery of the visceral covered stents (e.g., bridging stent grafts  940  shown in  FIG. 12 ). For example, balloon-expandable covered stent grafts (e.g., bridging stent grafts  940  shown in  FIG. 12 ) are deployed, which bridge the native renal artery with the internal branch, thereby creating a seal that excludes blood flow from the aneurysm sac but also promotes continued visceral perfusion. 
     At a step  1420 , main body  610  of branched bifurcated stent graft  600  is completely detached from primary stent graft sheath  710  of stent graft delivery system  700  via the removal of a constraining wire that is located along the posterior spine of branched main body stent graft  200  or branched bifurcated stent graft  600 . This is accomplished by the removal of a plug (not shown) that is attached to this constraining wire that is located just proximal to center shaft  716 . 
     At a step  1422 , the completion of the aortic repair consists of cannulation of the contralateral gate and deployment of an iliac limb stent graft (e.g., stent graft extension or proximal extension thoracic stent graft) consistent with currently marketed stent graft devices. The common femoral arteriotomy is then closed as per currently accepted methods. 
       FIG. 15  is a perspective view of an example of a branched bifurcated stent graft  1500  that comprises one or more external branches. In this example, branched bifurcated stent graft  1500  includes a main body  1510 , a first limb (or leg)  1512 , and a second limb (or leg)  1514 . Namely, first limb  1512  and second limb  1514  extend from the proximal end of main body  1510 , wherein first limb  1512  is longer than second limb  1514  and second limb  1514  is designed to receive a stent graft extension (not shown). 
     Main body  1510 , first limb  1512 , and second limb  1514  are flexible tubular-shaped members, each of which is a tubular metal web covered by a woven polyester sleeve. Accordingly, branched bifurcated stent graft  1500  is a covered stent. Main body  1510  has a distal end  1516 . First limb  1512  has a proximal end  1518 . Second limb  1514  has a proximal end  1520 . 
     Branched bifurcated stent graft  1500  comprises at least one external branch  1530  that protrudes from the side of main body  1510 . In the example shown in  FIG. 15 , branched bifurcated stent graft  1500  comprises three external branches  1530 . However, this is exemplary only. Branched bifurcated stent graft  1500  can comprise any number of external branches  1530 . In one example, each of the external branches  1530  is about 2 cm long and is about 7 mm in diameter. 
       FIG. 16  shows branched bifurcated stent graft  1500  of  FIG. 15  when deployed in, for example, the juxtarenal abdominal aorta  1600  and shown in relation to the renal arteries. Branched bifurcated stent graft  1500  can be prewired and deployed using, for example, stent graft delivery system  700 . In this example, the one or more external branches  1530  are used to deploy smaller renal stent grafts (or bridging stent grafts)  940  into, for example, the renal arteries of the abdominal aorta. 
     In branched bifurcated stent graft  1500 , by having the external branches  1530  protrude from the sides of main body  1510  upon deployment, the flow dynamics may be improved within main body  1510  of branched bifurcated stent graft  1500 . Additionally, the branched bifurcated stent graft  1500  with the external branches  1530  may serve to decrease type II endoleaks (i.e., back bleeding from spinal arteries that feed the aneurysm sac). Further, the use of external branches  1530  is not limited to bifurcated stent grafts only, rather external branches  1530  can also be used with main body stent grafts. 
     Following long-standing patent law convention, the terms “a,” “an,” and “the” refer to “one or more” when used in this application, including the claims. Thus, for example, reference to “a subject” includes a plurality of subjects, unless the context clearly is to the contrary (e.g., a plurality of subjects), and so forth. 
     Throughout this specification and the claims, the terms “comprise,” “comprises,” and “comprising” are used in a non-exclusive sense, except where the context requires otherwise. Likewise, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items. 
     For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing amounts, sizes, dimensions, proportions, shapes, formulations, parameters, percentages, parameters, quantities, characteristics, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about” even though the term “about” may not expressly appear with the value, amount or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are not and need not be exact, but may be approximate and/or larger or smaller as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art depending on the desired properties sought to be obtained by the presently disclosed subject matter. For example, the term “about,” when referring to a value can be meant to encompass variations of, in some embodiments, ±100% in some embodiments ±50%, in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed methods or employ the disclosed compositions. 
     Further, the term “about” when used in connection with one or more numbers or numerical ranges, should be understood to refer to all such numbers, including all numbers in a range and modifies that range by extending the boundaries above and below the numerical values set forth. The recitation of numerical ranges by endpoints includes all numbers, e.g., whole integers, including fractions thereof, subsumed within that range (for example, the recitation of 1 to 5 includes 1, 2, 3, 4, and 5, as well as fractions thereof, e.g., 1.5, 2.25, 3.75, 4.1, and the like) and any range within that range. 
     Although the foregoing subject matter has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be understood by those skilled in the art that certain changes and modifications can be practiced within the scope of the disclosed subject matter.