Abstract:
A modular prosthetic conduit system such as a stent or stent graft system tailored for the repair of aneurysms or other compromised vessel walls. The stent or stent graft system incorporates various means to interlock the multiple modular components used in the repair procedure. The present invention further provides a modular stent graft system tailored for the repair of aneurysms or other compromised vessel walls that cross or are adjacent to a branch or bifurcation in a vessel.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/835,789, filed Aug. 8, 2007 now abandoned, which is incorporated by reference herein in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to endoluminal prosthetic conduit systems and in particular to methods and components for joining together endoluminal prosthetic conduit components. 
     BACKGROUND OF THE INVENTION 
     Stents or stent grafts are forms of transluminal prosthetic components which are used to maintain, open or dilate stenotic lesions in body lumens or to cover and repair an aneurysm. It is often the case that an aneurysm occurs at a branch or bifurcation in a vessel. To repair such an aneurysm using modular components, one current technique is to initially deploy across the aneurysm a main body stent or stent graft having a side wall opening. The side wall opening is aligned with the side branch ostium. A second stent or stent graft is then deployed through the main body stent side wall opening and into the side branch vessel. This modular repair approach requires the modular components to be effectively sealed at their connection points to prevent blood leakage into the aneurysm. In addition the modular components must be locked or joined together to prevent subsequent relative displacement of the modular components. Similar requirements apply to those procedures that use multiple stent grafts that are coupled together to increase the effective length of the repair device. 
     SUMMARY OF THE INVENTION 
     The present invention provides modular prosthetic conduit systems such as stent or stent graft systems. The modular prosthetic conduit systems may be tailored for the repair of aneurysms or for the repair of compromised vessel walls. The systems incorporate various embodiments for the secure interlocking of the multiple modular components used in a vessel repair procedure. 
     An aspect of the invention includes a prosthetic conduit system comprising: an expandable main conduit having a first open end, a second open end, a main conduit wall extending therebetween, an outer conduit surface, and an inner conduit surface having at least one protuberance thereon; an expandable secondary conduit having a first open end, a second open end, a secondary conduit wall extending therebetween, and an attachment portion extending at an angle of less than 90 degrees from the secondary conduit wall when in a deployed state; and wherein at least a portion of the secondary conduit is sized to fit inside the main conduit. 
     A further aspect of the invention includes a prosthetic conduit system comprising: an expandable main conduit having a first open end, a second open end, a main conduit wall extending therebetween, at least one opening through the main conduit wall, and an internal channel having an inner surface, an outer surface, a first open end located within the main conduit and a second open end at the opening in the main conduit wall; an expandable secondary conduit having a first open end, a second open end, a secondary conduit wall extending therebetween, and an attachment portion extending at an angle of less than 90 degrees from the secondary conduit wall when in a deployed state; and wherein at least a portion of the secondary conduit is sized to fit inside the internal channel and through the opening in the main conduit wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a main conduit with an interconnected secondary conduit as implanted across an aortic aneurysm. 
         FIG. 2  is a perspective view of a main conduit having an internal protuberance. 
         FIG. 3  is a cross-sectional view of a main conduit having an internal protuberance. 
         FIG. 4  is a perspective view of a main conduit joined to a secondary conduit. 
         FIGS. 5A and 5B  are perspective and side views of a secondary conduit having an attachment portion. Shown is a defined angle between an attachment portion and a secondary conduit longitudinal axis or secondary conduit wall. 
         FIG. 6  is a cross-sectional view of a main conduit having an internal protuberance that is discontinuous or segmented. 
         FIG. 7  is a cross-sectional view of a main conduit having an internal protuberance that incorporates stiffening support structures. 
         FIG. 8  is a cross-sectional view of a main conduit having an internal stent or support structure with barbs or hooks configured to engage a secondary conduit. 
         FIGS. 9A and 9B  are cross-sectional views of a main conduit having internal barbs or internal hooks configured to engage a secondary conduit. 
         FIGS. 10A and 10B  are perspective views of a secondary conduit having external barbs or external hooks configured to engage a main conduit. 
         FIG. 11  is a perspective view of a secondary conduit having an external cuff that is configured to engage and lock onto an open end of a support channel. 
         FIG. 12  is a cross-sectional view of a main conduit having two opposed cuffs. 
         FIG. 13  is a side view of a secondary conduit having two opposed cuffs. 
         FIG. 14  is a perspective view of a main conduit and an interconnected secondary conduit. 
         FIGS. 15  A and  15 B are side views of main conduits according to certain aspects of the invention. 
         FIGS. 16  A and  16 B are side views of main conduits and secondary conduits according to certain aspects of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A better understanding of the invention will be had with reference to the several figures. 
     Shown in  FIG. 1  is a main conduit  20  having a first open end  22  and a second open end  24 . A secondary conduit  26  is shown inserted into the second open end  24  of the main conduit  20 . The secondary conduit  26  is shown as a bifurcated endoluminal device bridging an aortic aneurysm  28 . The main conduit  20  and the secondary conduit  26  are expanded and share an engagement portion or engagement length  30 . In an aspect of the invention the main conduit  20  and the secondary conduit  26  can be self-expanding or balloon expandable. 
     A main conduit can have various configurations including stent grafts with or without side-branches or side-branch openings. Stent grafts can be fabricated, for example, according to the methods and materials as generally disclosed in U.S. Pat. Nos. 6,042,605; 6,361,637; and 6,520,986 all to Martin et al. Details relating to the fabrication and materials used for a main conduit with an internal side branch support tube or channel can be found in, for example, U.S. Pat. No. 6,645,242 to Quinn. 
     The main conduit comprises at least one protuberance on the inner surface of the main conduit. Protuberances according to an aspect of the invention can be in many forms. For example, shown in  FIG. 2  is a perspective view of a main conduit  20  having a first open end  22  and a second open end  24 . Internal to the main conduit is protuberance in the form of cuff  32  on the inner surface of the main conduit. 
       FIG. 3  is a cross-sectional view of a main conduit  20  as viewed along the cross-sectional plane  3  of  FIG. 2 . Shown is a section of a main conduit  20 , first and second open ends  22 ,  24  and protuberance  32 . The protuberance  32  is in the form of a cuff  34  that is configured to engage an attachment portion of a secondary conduit. A protuberance or cuff can have various configurations and can be fabricated, for example, from tubes, sheets or films formed into tubular shapes, woven or knitted fibers or ribbons or combinations thereof. Protuberance or cuff materials can include conventional medical grade materials such as nylon, polyester, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylchloride, polyurethane and elastomeric organosilicon polymers. A protuberance or cuff can be joined to a graft or stent wall by sutures, medical grade adhesives or thermoplastics or can be integral to the graft or stent wall. 
     Shown in  FIG. 4  is a main conduit  20  having a first open end  22  and a second open end  24  and a wall  25  extending between the two open ends. The wall defines an outer conduit surface  21  and an inner conduit surface  23 . A secondary conduit  26  is shown inserted into the second open end  24  of the main conduit  20 . The secondary conduit  26  has a first open end  27  a second open end  29  and a wall  31  extending between the two open ends. The secondary conduit  26  has an attachment portion  36  shown in a deployed state as flared apices of a stent support structure. The attachment portion  36  is shown engaged into the protuberance  32  of main conduit  20 . The flared apices of the stent support are therefore engaged and interlocked into the cuff  34 , preventing or inhibiting the secondary conduit  26  from dislodging toward the direction indicated by arrow  38 . An improved sealing surface between the secondary and the main conduits may also be provided by the protuberance  32 . Forces exerted by the flow of blood may encourage or drive the flared apices of the stent support into contact with or full engagement with the cuff  34 . 
     Shown in  FIG. 5A  is a secondary conduit  26  having open ends  27  and  29 , a wall  31  extending from open end  27  to open end  29 , a longitudinal axis  40  and an attachment portion  36  shown in an unconstrained or deployed state as flared-out apices of a support stent. The inner surface  42  of the attachment portion  36  defines axis  44 . An angle  46  is shown between the secondary conduit longitudinal axis  40  (and the wall  31 ) and the attachment portion axis  44 . Shown is an angle of about 45°. Angle  46  can be any angle less than about 90°. For example angle  46  can be just less than 90°, about 80°, about 70°, about 60°, about 45°, about 30°, about 20° or less. 
     Similar to  FIG. 5A , shown in  FIG. 5B  is a secondary conduit  26  having open ends  27  and  29 , a wall  31  extending from open end  27  to open end  29 , a longitudinal axis  40  and an attachment portion  36  shown in a deployed state as flared-out apices of a support stent. The inner surface  42  of the attachment portion  36  defines axis  44 . An angle  46 ′ is shown between the secondary conduit wall  31  and the attachment portion axis  44 . Shown is an angle of about 45°. 
     Various alternate configurations of attachment portions and/or protuberances are possible. For example the protuberance  32  can be discontinuous, forming discrete protuberance segments along the inner wall of a main conduit. A main conduit can have two, three, four or five or more discrete protuberance segments, spaced along the inner wall. Shown in  FIG. 6  is a cross-sectional view of a main conduit  20  as viewed along the cross-sectional plane  3  as defined in  FIG. 2 . Shown is a section of a main conduit  20 , first and second open ends  22 ,  24  and discontinuous protuberances  34 . The protuberances  34  form a series of cuffs that are configured to engage attachment portions of a secondary conduit, such as depicted in  FIG. 4 . 
     To assist in the engagement of an attachment portion, a protuberance can incorporate semi-rigid or densified segments along its length. Such semi-rigid sections along a protuberance may prevent or inhibit the protuberance from collapsing. Shown in  FIG. 7  is a cross-sectional view of a main conduit  20  as viewed along the cross-sectional plane  3  as defined in  FIG. 2 . Shown is a section of a main conduit  20 , first and second open ends  22 ,  24  and a protuberance, shown as cuff  34 . Densified or semi-rigid sections  62  are incorporated into the protuberance to add rigidity to cuff  34  and thus inhibiting or even preventing the cuff from collapsing. Semi-rigid sections  62  can be incorporated into segmented or discontinuous protuberances as previously described in  FIG. 6 . 
     Semi-rigid or densified segments may be formed from conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol and biologically derived materials such as pericardium and collagen. Semi-rigid or densified segments can also comprise bioresorbable materials such as poly(amino acids), poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) and poly(orthoesters). 
     The at least one protuberance of the main conduit may comprise an internal stent or support structure that incorporates barbs, hooks or other suitable configurations to engage and/or lock with a secondary conduit. Shown in  FIG. 8  is a cross-sectional view of a main conduit  20  as viewed along the cross-sectional plane  3  of  FIG. 2 . Shown is a section of a main conduit  20 , first and second open ends  22 ,  24  and an internal stent or support structure  64 . Protruding out of the stent or support structure  64  are a series of barbs or hooks  66 . The barbs or hooks are oriented inwards toward the center of the main conduit and are configured to engage and/or lock onto a wall or attachment portion of a secondary conduit. 
     A main conduit may have a series of internal, barbs or hooks that are integral to the main conduit wall or integral to a main conduit support stent. For example if the main conduit has a stent support structure, portions of the stent can be formed into hooks or barbs that are configured to engage and lock a secondary conduit. Shown in  FIG. 9A  is a cross-sectional view of a main conduit  20  as viewed along the cross-sectional plane  3  of  FIG. 2 . Shown is a section of a main conduit  20 , first and second open ends  22 ,  24  and a series of internal barbs  68 . Similarly shown in  FIG. 9B  are a series of internal hooks  70 . The barbs or hooks are oriented inwards toward the center of the main conduit and are configured to engage and/or lock onto an external wall of a secondary conduit. Barbs or hooks may be formed from conventional medical grade materials such as those listed above. 
     Secondary conduits can also incorporate various forms of attachment portions to engage and/or lock onto main conduits. For example shown in  FIG. 10A  is a perspective view of a secondary conduit  26  having first and second open ends  27 ,  29  and a wall  31 . Protruding outwardly away from the secondary conduit wall  31  are a series of external barbs  72 . Similarly, shown in  FIG. 10B  are a series of external hooks  74 . The barbs or hooks are oriented outwardly away from the center of the secondary conduit and are configured to engage and lock onto an internal wall and/or protuberance of a main conduit. 
     A secondary conduit may also incorporate an external cuff that is configured to engage a main body protuberance or an open end of an internal channel. For example shown in  FIG. 11  is a perspective view of a secondary conduit  26  having first and second open ends  27 ,  29  and a wall  31 . Formed about the first open end  27  is an external cuff  76  configured to engage an internal protuberance or a first open end of an internal channel of a main conduit. The external cuff may incorporate semi-rigid sections as shown in  FIG. 7  to add rigidity to the cuff. 
     A main conduit may have opposed anchoring cuffs that prevent a secondary conduit from being displaced in two directions. Shown in  FIG. 12  is a cross-sectional view of a main conduit  20  having two opposed engagement cuffs  78 . The cuffs  78  are configured in a linear state as shown in  FIG. 2  and  FIG. 3 . The cuffs  78  are configured to engage attachment portions  36  of a secondary conduit  26 . The engagement of the attachment portions  36  to the cuffs  78  inhibit or prevent dislodgement of the secondary conduit in the two directions shown by arrows  38  and  80 . 
     Secondary conduits can also incorporate attachment portions in the form of bi-directional cuffs that inhibit or prevent dislodgement in two directions. Shown in  FIG. 13 , is a secondary conduit  26  having bi-directional cuffs  82 . The bi-directional cuffs  82  are configured to engage opposed main conduit cuffs as shown in  FIG. 12 . 
     In some surgical procedures it is desirable to have a side-branched endovascular device, particularly for the repair of a vessel that is in close proximity to branched vasculature. 
       FIG. 14  is a perspective view of an alternate main conduit  50  having a first open end  22  and a second open end  24 . Within the main conduit  50  is an internal channel  54  having a first open end  56  and a second open end  58  that is aligned to an opening  60  in the main conduit wall  25 . Such a main conduit can be fabricated according to the teaching in U.S. Pat. No. 6,645,242 to Quinn. A secondary conduit  26  having a first open end  27 , a second open end  29 , a wall  31 , and an attachment portion  36  in a deployed state is shown inserted into the internal channel  54 . The secondary conduit  26  is shown exiting out through the second open end  58  of the internal channel  54  and through the opening  60  in the main conduit wall. The attachment portion  36  is configured to engage and/or interlock onto the first open end  56  of the internal channel. This interlocking may prevent the dislodgement of the secondary conduit  26  along the direction depicted by arrow  38 . Forces exerted by the flow of blood may encourage or drive the attachment portion  36  into full contact with the first open end  56  of the internal channel  54 . 
     Stents can have various configurations as known in the art and can be fabricated, for example, from cut tubes, wound wires (or ribbons) or flat patterned sheets rolled into a tubular form. Stents can be formed from metallic, polymeric or natural materials and can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol and biologically derived materials such as bovine arteries/veins, pericardium and collagen. Stents can also comprise bioresorbable materials such as poly(amino acids), poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) and poly(orthoesters). 
     Grafts can have various configurations as known in the art and can be fabricated, for example, from tubes, sheets or films formed into tubular shapes, woven or knitted fibers or ribbons or combinations thereof. Graft materials can include conventional medical grade materials such as nylon, polyester, polyethylene, polypropylene, polytetrafluoroethylene (including expanded polytetrafluoroethylene (“ePTFE”)), polyvinylchloride, polyurethane and elastomeric organosilicon polymers. 
     Stents can be used alone or in combination with graft materials. Stents can be configured on the external or internal surface of a graft or may be incorporated into the internal wall structure of a graft. Moreover, main and secondary conduits can incorporate various stent or support structures. For example as shown in  FIG. 15A , a main conduit  20  may comprise separate stent segments  90 A and  92 A, positioned at or near the first and second open ends  22  and  24  of the main conduit  20 . Similarly the stent segments  90 A and  92 A can comprise a single stent  94 A extending from the first open end  22  to the second open end  24  of the main conduit  20 . 
     Shown in  FIGS. 16A and 16B  are secondary conduits  26  tailored to be inserted into main conduits  22  along direction arrows  96 . As shown in  FIG. 16A , a secondary conduit  26  can incorporate stents  90 B and  92 B at or near the first and second open ends  27  and  29  of the secondary conduit  26 . Similarly the stent segments  90 B and  92 B can comprise a single stent  94 B extending from the first open end  27  to the second open end  29  of the secondary conduit  26 . 
     Expandable conduits according to the invention can be delivered in a constrained state endoluminally by various catheter based procedures known in the art. For example self-expanding endoluminal devices can be loaded onto the distal end of a catheter, compressed and maintained in a constrained state by an external sheath. The sheath can be folded to form a tube positioned external to the compressed device. The sheath edges can be sewn together with a deployment cord that forms a “chain stitch”. Once the constrained device is positioned at a target site within a vessel the device can be deployed. In the deployed state, the device may still be constrained by the vasculature or by another device. For example a device may assume a diameter of 20 mm when fully un-constrained. This same device may be deployed into a vessel (or other device) having a lumen diameter of 15 mm and would therefore be “constrained” in the deployed state. An “un-constrained state” can therefore be defined as the state assumed by the device when there are no external forces inhibiting the full expansion of the device. A “constrained state” can therefore be defined as the state assumed by the device in the presence of external forces that inhibit the full expansion of the device. The deployed state can be defined as the state assumed by the device when expanded into a vessel or other device. 
     To release and deploy the constrained device, one end of the deployment cord can be pulled to disrupt the chain stitch, allowing the sheath edges to separate and release the constrained device. Constraining sheaths and deployment cord stitching can be configured to release a self-expanding device in several ways. For example a constraining sheath may release a device starting from the proximal device end, terminating at the distal device end. In other configurations the device may be released starting from the distal end. Self expanding devices may also be released from the device center as the sheath disrupts towards the distal and proximal device ends. Details relating to constraining sheath materials, sheath methods of manufacture and main body compression techniques can be found in U.S. Pat. No. 6,352,561 to Leopold et al., and U.S. Pat. No. 6,551,350 Thornton et al. 
     In the deployment of a secondary conduit for example, the secondary conduit can be released from a constraining sheath starting at the proximal (or hub) end of the constrained conduit. In typical procedures, the attachment portion of the secondary conduit is located about the proximal end of the conduit and in an aspect of the invention this proximal end is the first end released from a constraining sheath, thus also deploying the attachment portion. 
     While particular embodiments of the present invention have been illustrated and described above, the present invention should not be limited to such particular illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims.