Abstract:
Implementations of the present disclosure relate to apparatuses, systems, and methods for anastomosing vascular systems in medical procedures. A pair of similar or identical coupling devices may be disposed at the ends of two vessels, either natural or synthetic. The coupling devices may be capable of hermaphroditically connecting to one another to provide a simple and secure connection which promotes growth of the vessels between the bio-absorbable coupling devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/921,324 entitled “VASCULAR COUPLING DEVICE”, filed Dec. 27, 2013, which is incorporated herein in its entirety by this reference. 
     
    
     BACKGROUND 
       [0002]    1. The Field of the Disclosure 
         [0003]    Generally, this disclosure relates to surgical anastomosis. More specifically, the present disclosure relates to devices, systems, methods that related to the mechanical coupling of vasculature, natural or synthetic, in a medical setting. 
         [0004]    2. Background and Relevant Art 
         [0005]    Anastomosis is the connection of the vessels within a body. While it may refer generally to conduits within a body, anastomosis as used herein may refer to circulatory anastomosis, in which vascular tissue may be connected or reconnected. The circulatory system is very complex and its proper function is critical to a patient&#39;s health and wellbeing. However, a surgeon may need to bypass or modify a patient&#39;s circulatory system to provide proper therapeutic treatments. 
         [0006]    Unfortunately, the vasculature of a patient consists of small conduits that can be difficult to handle and manipulate properly, even when considered independent of the small incisions, bodily fluids present, and other complicating factors that commonly occurring during procedures in an operating room. Blood vessels may be relatively small and difficult to handle properly in order to perform common methods of connecting tissue, such as suturing. Furthermore, the small structures of the vasculature may not be suitable for other connection methods, such as surgical staples, as the staples would damage the walls of the blood vessel or constrict flow therethrough. 
         [0007]    Conventional microsurgical vessel anastomosis is hand suturing the two cut ends of an artery or vein together using ultrafine techniques with the assistance of an operating microscope. This technique requires specialized training, is time consuming, is expensive when considering doctor and operating room time, and is subject to a great degree of human error. 
       BRIEF SUMMARY 
       [0008]    Implementations of the present disclosure solve one or more of the foregoing or other problems in the art with apparatuses, systems, and methods for surgical anastomosis. 
         [0009]    In an embodiment, a vascular coupling device for providing a coupling site on a vessel may comprise a back ring configured to slide around the vessel. An engaging coupler, with an inner surface having a diameter greater than a diameter of an outer diameter of the back ring, may be disposed around the back ring. An end of the vessel may be everted over the outer surface of the back ring and compressed between the inner surface of the engaging coupler and the outer surface of the back ring. The vascular coupling device may further comprise a plurality of engaging arms extending longitudinally from an outer surface of the engaging coupler. The engaging arms may have a length sufficient to reach around a second coupling device and engage a back ring of a second coupling device. 
         [0010]    A vascular coupling system for coupling a first vessel to a second vessel is also presented. The system may comprise a first coupling device and a second coupling device. The first and second coupling device may each comprise a back ring and an engaging coupler as previously described. The first coupling device and second coupling device may further be identical. The first and second coupling devices may be configured to hermaphroditically engage one another. In an embodiment, the first and second coupling devices may engage one another when oriented at a rotational offset from one another. 
         [0011]    A method for coupling a first vessel to a second vessel is also presented herein. In an embodiment, the method may comprise positioning a first back ring circumferentially around an end of the first vessel and everting the end of the first vessel over an outer diameter of the first back ring. The method may further comprise assembling a first coupling device by sliding an inner surface of a first engaging coupler over the end of the first vessel and an outer surface of the first back ring. Sliding the inner surface of the first engaging coupler over the end of the first vessel and an outer surface of the first back ring may create a friction fit of the first engaging coupler and the first back ring with the end of the first vessel disposed therebetween that is substantially sealed. The method may further comprise engaging the first coupling device with a second coupling device, wherein a plurality of engaging arms extending from the first engaging coupler fit within a recessed portion of the second coupling device. 
         [0012]    Additional features and advantages of exemplary implementations of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic, it should be understood that at least part of drawings may be drawn to scale. Understanding that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0014]      FIGS. 1A-B  are perspective views of components of a vascular coupling device, according to at least one embodiment of the present disclosure; 
           [0015]      FIG. 2  is a perspective view of two vascular coupling devices in accordance with the present disclosure engaged and forming a fluid connection; 
           [0016]      FIGS. 3A-E  are perspective views of the installation and coupling of the two vascular coupling devices of  FIG. 2 ; 
           [0017]      FIG. 4  is a perspective view of another embodiment of an engaging coupler having proximal engaging arms 
           [0018]      FIG. 5  is a perspective view of a vascular coupling device having a back ring and an engaging coupler including proximal engaging arms; 
           [0019]      FIG. 6  is a perspective view of alternative embodiments of two vascular coupling devices in accordance with the present disclosure engaged and forming a fluid connection; and 
           [0020]      FIGS. 7A-B  depict yet another embodiment of a vascular coupling device with extensions to limit relative rotation of components. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    One or more implementations of the present disclosure relate to assembling and installing vascular coupling devices that are secured to a blood vessel and couple to one another. The vascular coupling devices may secure to the end of the vessel without piercing or puncturing the vessel wall. The vascular coupling device may then secure to another vascular coupling device simply and reliably, providing a bio-absorbable connection that is easy to install. 
         [0022]    A vascular coupling device may have two parts that combine via a friction fit to simultaneously form the vascular coupling device and to reliably retain the end of the vessel relative to the vascular coupling device. A user may pass the end of a vessel through the annular back ring and then evert the end of the vessel outward and over the outer surface of the back ring. A user may then slide the engaging coupler over the outer surface of the back ring and the everted vessel now laid thereupon. Pressing the engaging coupler may create a substantially watertight (i.e., fluid tight) friction fit such that the vessel now terminates in the coupling device. A user may then affix a similar vascular coupling device on a second vessel. The two vascular coupling devices may each be able to mutually engaged one another to provide a secure connection wherein the vessel walls are urged against one another to promote vessel growth. 
         [0023]      FIG. 1A  shows an engaging coupler  102  and  FIG. 1B  depicts a top perspective and bottom perspective of a back ring  104 , which may collective form a vascular coupling device  100 . In an embodiment, the engaging coupler  102  and the back ring  104  may comprise a bio-absorbable or bio-compatible material. For instance, exemplary bio-compatible materials may include organic materials, metals, alloys, polymers, composites, and combinations thereof. According to at least one example, the engaging coupler  102  and the back ring  104  may be made from a biocompatible material such as silicone, high density polyethylene (“HDPE”), polymethyl methacrylate (“PMMA”), or combinations thereof. In other embodiments, biocompatible materials such as titanium, cobalt, platinum, nickel, stainless steel, other materials, alloys thereof, or combinations of the foregoing may also be utilized. The engaging coupler  102  and the back ring  104  may be designed to remain in the body indefinitely, or may degrade over time. For instance, the engaging coupler  102  and the back ring  104  may be formed of a biodegradable, bioerodable, bioresorbable, or other degrading or resorbing material or combinations thereof. Examples of such materials that may be suitable for the manufacture of the device may include, but are not limited to, poly(lactic-co-glycolic acid) (“PLGA”), collagen, spun silk, electrospun silk, polytetrafluoroethylene (“PTFE”), polydimethylsiloxane (“PDMS”), silicone, a salicylic acid-based polymer, a salicylsalicylic acid-based polymer, a difluorophenyl-salicylic acid-based polymer, collagen, fibrin, fibronectin, alginate, poly-glycolic acid, poly-(lactic acid), poly-caprolactone, poly-(L-lactic acid), poly(3-hydroxybutyric acid), poly((bis(hydroxyethy) terephthalate-ethyl phosphoester/terephthaloyl chloride), gelatin, keratin, thrombin, poly(2-hydroxyethyl methacrylate) (“PHEMA”), a co-polymer of PHEMA and methyl methacrylate, poly(acrylonitrile-co-methylacrylate), or combinations thereof. 
         [0024]    The back ring  104  may have an inner surface  106  that is smooth. The smooth inner surface  106  of the back ring  104  may help prevent damage to the vessel wall during anastomosis. The back ring  104  may also have an outer surface  108 . The outer surface  108  may have a constant radius, or may taper slightly, such that the top portion of the outer surface  108  has a smaller radius than the bottom portion of the outer surface  108 . A tapered outer surface  108  may assist in forming a friction fit with an inner surface  110  of a body of the engaging coupler  102 . The back ring  104  may also have a rear face  112  with a circular groove  114  disposed therein. The circular groove  114  provides a recessed portion of the rear face  112  with which a second vascular coupling device may engage. 
         [0025]    The engaging coupler  102  may have various shapes. In some embodiments, the engaging coupler  102  may be an engaging ring with a body having an annular structure. In other embodiments, the engaging coupler  102  may be elliptical, polygonal, irregularly shaped, or combinations thereof. The inner surface  110  of the body of the engaging coupler  102  may be configured to complimentarily mate with the outer surface  108  of the back ring  104 . In yet other embodiments, the engaging coupler  102  may not surround the entire outer surface  108  of the back ring  104 . For example, the engaging coupler  102  may have a body with an opening or break allowing the engaging coupler  102  to expand and/or contract radially and clip around at least a portion of the back ring  104 . 
         [0026]    The engaging coupler  102  may comprise at least one resilient engaging arm  116 . While  FIG. 1A  depicts an embodiment of the engaging coupler  102  with two engaging arms  116 , other numbers of engaging arms  116  are possible, and in other embodiments, the engaging coupler  102  may have one, three, four, or more engaging arms  116 . The engaging arms  116  may extend longitudinally from the body of the engaging coupler  102  and be disposed around the circumference of the engaging coupler  102 . In an embodiment, the engaging arms  116  are disposed at equal angular displacements. For example, when the engaging coupler  102  comprises two engaging arms  116 , the engaging arms may be disposed at about 180° intervals. In another example, when the engaging coupler  102  comprises three engaging arms  116 , the engaging arms may be disposed at about 120° intervals. However, in another embodiment, the engaging arms  116  may be disposed at unequal intervals. For example, when the engaging coupler  102  comprises two engaging arms  116 , the engaging arms  116  may be disposed at about a 90° interval and about a 270° interval. 
         [0027]    The engaging coupler  102  may also comprise a plurality of cuts  118  in an outer surface  120  of the engaging coupler  102 . While  FIG. 1A  depicts an embodiment of the engaging coupler  102  with two cuts  118 , other numbers of cuts  118  are possible, and in other embodiments, the engaging coupler may have three or four cuts  118 . In an embodiment, the cuts  118  are disposed at equal angular displacements. For example, when the engaging coupler  102  comprises two cuts  118 , the engaging arms may be disposed at about 180° intervals. In another example, when the engaging coupler  102  comprises three cuts  118 , the engaging arms  116  may be disposed at 120° intervals. However, in another embodiment, the cuts  118  may be disposed at unequal intervals. For example, when the engaging coupler  102  comprises two cuts  118 , the cuts  118  may be disposed at about a 90° interval and about a 270° interval. In another example, there may be more or fewer cuts  118  than there are engaging arms  116  (e.g., one cut  118  per two engaging arms  116  or two cuts  118  per one engaging arm  116 ). 
         [0028]    As shown in  FIG. 2 , the engaging arms  116  may further comprise engaging features to engage with a second vascular coupling device  200 . The engaging features of the first vascular coupling device  100  may include a hook  122  with a beveled face  124  and undercut groove  126  with an associated tab  128 . In some embodiments, the engaging arms  116  may have a length sufficient to extend beyond the rear face  112  of a second vascular coupling device  200 . When the engaging arms  116  extend beyond the rear face  112  of the second vascular coupling device  200 , the hooks  122  on the engaging arms  116  may extend laterally and contact the rear face  112 . Furthermore, the undercut groove  126  and associated tab  128  may interface with the circular groove  114  on the rear face  112  of the second vascular coupling device  200 . In other embodiments, other engaging features may be used. For example, the engaging features may include threads for engaging a threaded portion of the second vascular coupling device  200 . In another example, the engaging features may include a snap fit ramp that may be inserted into a corresponding slot in the second vascular coupling device  200 . Furthermore, in some embodiments the engaging features may vary depending on the engaging arm  116 . In yet other examples, the engaging feature may be one or more features (e.g., a coating or surface texture) to enhance or facilitate the frictional force between the engaging coupler  102  and the back ring  104 . 
         [0029]    As can be seen in  FIG. 2 , the first vascular coupling device  100  and second vascular coupling device  200  may mutually engage when coupled. In at least one embodiment, the first vascular coupling device  100  and second vascular coupling device  200  may be identical in structure, and the connection therebetween may be hermaphroditic. In other embodiments, the first vascular coupling device  100  and second vascular coupling device  200  may not be identical although the connection therebetween may be hermaphroditic. In the embodiment depicted in  FIG. 2 , the first vascular coupling device  100  and second vascular coupling device  200  are identical embodiments having two engaging arms  116  and two cuts  118  in each coupling device. The first and second vascular coupling devices  100 ,  200 , have engaging arms  116  disposed about 180° from one another and cuts  118  disposed about 180° from one another and about 90° from either of the engaging arms  116 . The cuts  118  may interact with the beveled faces  124  of the hooks  122  on the engaging arms  116  to urge the resilient engaging arms  116  radially outward and around the outer surface  120  of the engaging coupler  102 . Therefore, to ensure proper alignment of the cuts  118  and the beveled faces  124  of the hooks  122  on the engaging arms  116 , the first vascular coupling device  100  and second vascular coupling device  200  may be oriented with about a 90° rotational offset from one another prior to coupling. To aid in preventing subsequent rotation of the first vascular coupling device  100  and second vascular coupling device  200  relative to one another, the outer surface  120  of the engaging coupler  102  may be non-circular, such as elliptical, with the engaging arms  116  disposed at a major axis and the cuts  118  disposed at a minor axis of the ellipse. 
         [0030]    A method for anastomosing is also described herein and depicted in  FIGS. 3A-E . The method may comprise sliding a back ring  104  around a vessel  130  ( FIG. 3A ). In an embodiment, approximately 2 mm to approximately 3 mm of the vessel protrudes from the back ring  104 . In some embodiments, the back ring may be fixedly attached to the engaging coupler  102 . For example, as will be described below, a proximally extending engaging arm may limit proximal movement of the back ring. The protruding end  132  of the vessel  130  may then have one or more slits  134  cut approximately one-half to approximately two-thirds of the distance to the back ring  104  ( FIG. 3B ). In the aforementioned embodiment, the one or more slits  134  may extend about 1 mm to about 2 mm longitudinally into the vessel  130 . 
         [0031]    The protruding end  132  of the vessel  130  may be everted over the outer surface  108  of the back ring  104 . An engaging coupler  102  may then be slid onto the outer surface  108  of the back ring  104  and may compresses the everted protruding end  132  of the vessel  130  to secure the first vascular coupling device  100  on the end of the vessel  130  ( FIG. 3C ). 
         [0032]    The acts depicted in  FIGS. 3A through 3C  may be repeated to secure a second vascular coupling device  200  to a second vessel  230 . The first vascular coupling device  100  and the second vascular coupling device  200  may then be oriented with a rotational offset from one another to align the engaging arms  116  of first vascular coupling device  100  with the cuts  218  of the second vascular coupling device  200  ( FIG. 3D ) and the engaging arms  216  of the second vascular coupling device  200  with the cuts  118  of the first vascular coupling device  100 . In the depicted embodiment, the offset is about 90°, but in embodiments with other numbers of engaging arms  116 ,  216 , the offset may be about 60°, about 45°, or other angles. 
         [0033]    The first vascular coupling device  100  and the second vascular coupling device  200  may then be moved toward one another. The beveled faces  124  of the hooks  122  on the engaging arms  116  of the first vascular coupling device  100  may interact with the cuts and urge the resilient engaging arms  116  outward and around the outer surface  220  of the engaging coupler  202  of the second vascular coupling device  200 . When the first vascular coupling device  100  and the second vascular coupling device  200  meet, the first vessel  130  and the second vessel  230  may contact one another. Additionally, the hooks  122  on the engaging arms  116  of the first vascular coupling device  100  may extend radially inward and contact a back ring  204  of the second vascular coupling device  200 . Furthermore, the undercut groove  126  and associated tab  128  of the hooks  122  on the engaging arms  116  of the first vascular coupling device  100  may interface with the rear face  212  and circular groove  214  of the second vascular coupling device  200 , securing the first vascular coupling device  100  to the second vascular coupling device  200  ( FIG. 3E ). 
         [0034]      FIG. 4  shows an alternative embodiment of an engaging coupler  302  and  FIG. 5  depicts a bottom perspective exploded view of yet another embodiment of an engaging coupler  402  and an alternative embodiment of a back ring  404 . The embodiments shown in  FIGS. 4-6  may include any or all of the components of the embodiments shown and/or described in connection with  FIGS. 1-3E . Thus, the various alternatives presented in the alternative embodiments shown and/or described in connection with  FIGS. 4-6  may be combined with any of the various alternatives presented in the alternative embodiments shown and/or described in connection with  FIGS. 1-3E . Similar components may be identified by like numbers. 
         [0035]    In the illustrated embodiment, the engaging coupler  302  and the back ring  304  may comprise a bio-absorbable or bio-compatible material as described herein. The back ring  304  may have an inner surface  306  and an outer surface  308 . The back ring  304  may also have a rear face  312 . 
         [0036]    The engaging coupler  302  may comprise at least one resilient distally extending engaging arm (“distal engaging arm”)  316   a . While  FIG. 4  depicts an embodiment of the engaging coupler  302  with two distal engaging arms  316   a , other numbers of distal engaging arms  316   a  are possible, and in other embodiments, the engaging coupler  302  may have one, three, four, or more distal engaging arms  316   a . The engaging coupler  302  may comprise at least one proximally extending engaging arm (“proximal engaging arm”)  316   b . Although shown with two proximal engaging arms  316   b , more or fewer proximal engaging arms  316   b  may be used. Additionally, as with the embodiment of an engaging coupler  302  shown in  FIGS. 4-6 , the embodiment of an engaging coupler  102  shown in  FIGS. 1-3E  may include any number of engaging arms (i.e., 0, 1, 2, 3, 4 or more), which may extend distally (such as engaging arms  116  or  316   a ) and/or proximally (such as engaging arms  316   b ). The engaging arms  316   a ,  316   b  may extend longitudinally from the annular engaging coupler  302  and be disposed around the circumference of the engaging coupler  302 . In an embodiment, the engaging arms  316   a ,  316   b  are disposed at equal angular displacements and/or unequal intervals. Furthermore, the distal engaging arms  316   a  and the proximal engaging arms  316   b  may be circumferentially aligned (as shown in  FIGS. 4-6 ), circumferentially misaligned, otherwise aligned, or combinations thereof. 
         [0037]    In some embodiments, the proximal engaging arms  316   b  may engage with a back ring by a friction force (e.g., an interference fit) with a surface of the back ring. In other embodiments, the proximal engaging arms  316   b  may have engaging features similar to the distal engaging arms  316   a  or different from the distal engaging arms  316   a . For example, the distal engaging arms  316   a  may have engaging features including hooks  322   a  with a beveled face  324   a  and a tab  328   a . In some embodiments, the proximal engaging arms  316   b  may have engaging features including hooks  322   b  with a beveled face  324   b  and a tab  328   b . The engaging features of the proximal engaging arms  316   b  may be configured to engage with a back ring. 
         [0038]      FIG. 5  illustrates vascular coupling device  400  including an engaging coupler  402  having proximal engaging arms  416   b  similar to or the same as engaging arms  316   b  described in relation to  FIG. 4 . The proximal engaging arms  416   b  may interact with a back ring  404 . For example, the proximal engaging arms  416   b  may include engaging features such as a hook  422   a  with a beveled face  424   a  and an associated tab  428   a . The proximal engaging arms  416   b  may limit proximal motion of the back ring  404  when the engaging coupler  402  is engaged with the back ring  404  prior to and/or during engagement with a second vascular coupling device. 
         [0039]    The engaging coupler  402  may also comprise a plurality of cuts  418  in an outer surface  420  of the engaging coupler  402 . The engaging coupler  402  may not include any cuts or may include any number of cuts  418 . The number of cuts  418  may or may not correspond to a number of engaging arms (i.e.,  116 ,  416 ) in a second vascular coupling device. The cuts  418  may be disposed at equal or unequal angular displacements. 
         [0040]    The engaging arms  416  may further comprise engaging features to engage with a second vascular coupling device. The engaging features may include a hook  422   a  with a beveled face  424   a  and an associated tab  428   a . As can be seen in  FIG. 6 , in an embodiment, the distal engaging arms  416   a  may have a length sufficient to extend beyond the rear face  512  of a second vascular coupling device  500 . When the distal engaging arms  416   a  extend beyond the rear face  512  of the back ring  504  of the second vascular coupling device  500 , the hooks  422   a  on the distal engaging arms  416   a  may extend laterally and contact the rear face  512 . In other embodiments, other engaging features may be used. 
         [0041]    As can be seen in  FIG. 6 , the first vascular coupling device  400  and the second vascular coupling device  500  may mutually engage when coupled. In an embodiment, the first vascular coupling device  400  and second vascular coupling device  500  may be similar or identical in structure, and the connection therebetween may be hermaphroditic. In other embodiments, the first vascular coupling device  400  and second vascular coupling device  500  may not be identical although the connection therebetween may be hermaphroditic. In the embodiment depicted in  FIG. 6 , the first vascular coupling device  400  and second vascular coupling device  500  are identical embodiments having two pluralities of distal engaging arms  416   a ,  516   a  and two pluralities of proximal engaging arms  416   b ,  516   b  and two cuts (not shown) in each coupling device. The first and second coupling devices  400 ,  500 , have engaging arms  416   a ,  516   a ,  416   b ,  516   b  disposed about 180° from one another and cuts  418  disposed about 180° from one another. The first vascular coupling device  400  and second vascular coupling device  500  may be rotated about 90° relative to one another. 
         [0042]    A plurality of cuts may interact with the beveled faces  424 ,  524  of the hooks  422 ,  522  on the distal engaging arms  416   a ,  516   a  of the first vascular coupling device  400  and the second vascular coupling device  500 , respectively, to urge the resilient distal engaging arms  416   a ,  516   a  radially outward and around the outer surface  420 ,  520  of the engaging couplers  402 ,  502 . Therefore, to ensure proper alignment of the cuts and the beveled faces  424 ,  524  of the hooks  422 ,  522  on the engaging arms  416   a ,  516   a , the first vascular coupling device  400  and second vascular coupling device  500  may be oriented with about a 90° rotational offset from one another prior to coupling. To aid in preventing subsequent rotation of the first vascular coupling device  400  and second vascular coupling device  500  relative to one another, the outer surface  420 ,  520  of the engaging coupler  402 ,  502  may be elliptical, with the distal engaging arms  416   a ,  516   a  disposed at a major axis and the cuts disposed at a minor axis of the ellipse. 
         [0043]      FIGS. 7A-B  illustrate yet another embodiment of a vascular coupling device  600  including at least one feature to limit the rotational movement of a first vascular coupling device relative to a second vascular coupling device.  FIG. 7A  is an exploded view of yet another embodiment of a vascular coupling device  600  having and engaging coupler  602  and a back ring  604 . The engaging coupler  602  may include a plurality of distal engaging arms  616   a  and proximal engaging arms  616   b . The proximal engaging arms  616   b  may be configured to engage with and limit the movement of a back ring  604 . The back ring  604  may include one or more lateral extensions  636 . The lateral extensions  636  may allow the back ring  604  to have an outer diameter at the lateral extensions  636  that is greater than an inner diameter defined by the plurality of distal engaging arms  616   a  and/or proximal engaging arms  616   b . For example, the distal engaging arms  616   a  and/or proximal engaging arms  616   b  may define a distance therebetween larger than at least a portion of the back ring  604  but smaller than another portion of the back ring  604  including the lateral extensions  636 . 
         [0044]      FIG. 7B  illustrates a first vascular coupling device  600  and a second vascular coupling device  700  coupled together. The engaging coupler  602  and back ring  604  of the first vascular coupling device  600  are coupled together with a plurality of engaging features (i.e., hooks  622   b ) on the proximal engaging arms  616   b  in contact with a rear face  612  of the back ring  604 . In some embodiments, the back ring  604  and engaging coupler  602  may be rotatable relative to one another when engaged. In other embodiments, rotational movement of the back ring  604  and the engaging coupler  602  may be limited or prevented when engaged. For example, the rotational movement of the back ring  604  and the engaging coupler  602  may be limited or prevented by friction, an adhesive, a mechanical fastener, or by physical contact between a portion of the engaging coupler  602  and the back ring  604 . The proximal engaging arms  616   b  may contact the rear face  612  of the back ring  604 . At least one proximal engaging arm  616   b  may contact or be adjacent to at least one lateral extension  636  when the engaging coupler  602  and back ring  604  are rotated relative to one another. The contact of the proximal engaging arms  616   b  and the lateral extensions  636  may limit or prevent the rotation of the engaging coupler  602  and back ring  604  are rotated relative to one another. 
         [0045]    As described herein, the first vascular coupling device  600  and second vascular coupling device  700  may be oriented at an angle (e.g., a rotational angle) relative to one another. The rotational offset of the first vascular coupling device  600  and second vascular coupling device  700  may have a rotational gap between the distal engaging arms  616   a  of the first vascular coupling device  600  and the distal engaging arms  716   a  of the second vascular coupling device  700 . The rotational gap between the distal engaging arms  616   a  of the first vascular coupling device  600  and the distal engaging arms  716   a  of the second vascular coupling device  700  may be within a range having upper and lower values including any of 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, or any value therebetween. For example, the rotational gap may be between 30° and 75°. In another example, the rotational gap may be between 45° and 65°. 
         [0046]    In some embodiments, the lateral extension  636  of the first vascular coupling device  600  and/or a lateral extension  736  of the second vascular coupling device  700  may be configured to occupy a portion of the rotational gap and limit rotational movement of the first vascular coupling device  600  and second vascular coupling device  700  relative to one another. The lateral extension  636  of the first vascular coupling device  600  and/or the lateral extension  736  of the second vascular coupling device  700  may be configured to occupy a percentage of the rotational gap having upper and lower values including any of 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any value therebetween. For example, the lateral extension  636  of the first vascular coupling device  600  and/or the lateral extension  736  of the second vascular coupling device  700  may occupy a percentage of the rotational gap between 50% and 95%. In another example, the lateral extension  636  of the first vascular coupling device  600  and/or the lateral extension  736  of the second vascular coupling device  700  may occupy a percentage of the rotational gap between 60% and 90%. In yet another example, the lateral extension  636  of the first vascular coupling device  600  and/or the lateral extension  736  of the second vascular coupling device  700  may occupy a percentage of the rotational gap between 80% and 90%. 
         [0047]    A vascular coupling device or system of a plurality of vascular coupling devices according to the present disclosure may allow the fluid communication between a first vessel and second vessel. The first vessel and second vessel may be contact with one another to facilitate intergrowth and healing of the vessel without further damage to or interference with the vessel wall by the vascular coupling device. 
         [0048]    The articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value. 
         [0049]    A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims. 
         [0050]    The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements. 
         [0051]    The present disclosure may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. Changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.