Abstract:
A stent graft introducer has a nose cone dilator ( 8 ) and a distally opening capsule ( 18 ) on the nose cone dilator, a balloon guide ( 2, 30 ) extending into the capsule and affixed therein. Upon completion of deployment of a stent graft, a balloon catheter ( 96 ) including an inflatable balloon ( 98 ) thereon can be advanced over the balloon guide at least partially into the nose cone whereby the balloon can be inflated therein to provide a smooth transition from the nose cone to a delivery sheath ( 10 ) for retraction of the nose cone dilator through the deployed stent graft. The balloon guide can be a separate wire ( 30 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of provisional application Ser. No. 60/832,865, filed Jul. 24, 2006. 
    
    
     TECHNICAL FIELD 
     This invention relates to a medical device and more particularly to a medical device used for deployment of an intraluminal graft or stent graft. 
     BACKGROUND OF THE INVENTION 
     In the deployment of a graft or stent graft into the human or animal body via intraluminal techniques a deployment device is used to introduce the graft and, after the graft has been deployed and expanded within the lumen, the introducer needs to be retracted. 
     One form of introducer uses a distally facing capsule to encompass an exposed stent of a stent graft during introduction and after the stent graft has been released and the capsule has been removed from the exposed stent, the capsule along with the introducer must withdrawn. The capsule, however, has a distally facing opening and edge and this can engage with stents of the just introduced stent graft and cause problems with dislodging the stent graft from its position on the wall of the lumen. Similarly, an introducer often has a sheath which is used to constrain a stent or stent graft during delivery and is withdrawn from the stent or stent graft to release the stent or stent graft. This sheath has a proximally facing opening and edge and if the sheath is advanced to meet the nose cone then that edge may engage with stents of the just introduced stent graft and cause problems with dislodging the stent graft from its position on the wall of the lumen. 
     It is the object of this invention to provide an arrangement by which the nose cone can be retracted to the sheath so that introducer as a whole can be retracted without causing such problems. 
     Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis means the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood. 
     SUMMARY OF THE INVENTION 
     In one form therefore the invention is said to reside in a stent graft introducer comprising a nose cone dilator and a distally opening capsule on the nose cone dilator and a balloon guide extending into the capsule and affixed therein whereby upon completion of deployment of a stent graft from the introducer, a balloon catheter including an inflatable balloon thereon can be advanced over the balloon guide at least partially into the nose cone and the balloon be inflated therein to provide a smooth transition from the nose cone to a delivery catheter for retraction of the nose cone dilator through the deployed stent graft. 
     Preferably the balloon is a non-compliant balloon whereby upon inflation it inflates to a selected size and shape only. 
     Preferably the introducer further comprises a guide wire catheter extending to and through the nose cone dilator and the balloon guide is the guide wire catheter. Alternatively the balloon guide is a separate guide wire. 
     In an alternate form the invention resides in a stent graft introducer comprising guide wire catheter, a nose cone dilator on the proximal end of the guide wire catheter, a distally opening capsule on the nose cone dilator, a sheath coaxially around the guide wire catheter and spaced apart therefrom to define an annular sheath lumen therein and a balloon guide extending through the sheath lumen and into the capsule and affixed therein, whereby upon completion of deployment of a stent graft, a balloon catheter including an inflatable balloon thereon can be advanced over the balloon guide at least partially into the nose cone and the balloon be inflated therein and the nose cone dilator and the inflated balloon retracted together such that the inflated balloon docks into the sheath whereby provide a smooth transition from the nose cone to the sheath for retraction of the stent graft introducer through the deployed stent graft. 
     Preferably the balloon is a non-compliant balloon whereby upon inflation it inflates to a selected size and shape only and is shaped to be substantially the same diameter as the sheath when in an inflated state. 
     In one embodiment the guide wire catheter is the balloon guide or alternatively the balloon guide is a separate guide wire extending through the sheath lumen. 
     In an alternate form the invention resides in a stent graft introducer comprising guide wire catheter, a nose cone dilator on the proximal end of the guide wire catheter, a distally opening capsule on the nose cone dilator, a sheath coaxially around the guide wire catheter and spaced apart therefrom to define an annular sheath lumen therein, a balloon guide extending through the sheath lumen into the capsule and affixed therein, a stent graft retained in the sheath lumen distally of the capsule, the stent graft comprising a proximally extending exposed stent and the proximally extending exposed stent being received and retained in the capsule of the nose cone dilator, whereby upon completion of deployment of the stent graft by retraction of the sheath and advancement of the nose cone dilator to remove the capsule from the proximally extending exposed stent, a balloon catheter including an inflatable balloon thereon can be advanced over the balloon guide at least partially into the nose cone whereby the balloon can be inflated therein and the nose cone dilator and the inflated balloon retracted such that the inflated balloon docks into the sheath whereby provide a smooth transition from the nose cone to the sheath for retraction of the stent graft introducer through the deployed stent graft. 
     Preferably the balloon is a non-compliant balloon whereby upon inflation it inflates to a selected size and shape only and is shaped to be substantially the same diameter as the sheath when in an inflated state. 
     In one embodiment the guide wire catheter extending is the balloon catheter and during the deployment of the stent graft the balloon catheter including the inflatable balloon is on the guide wire catheter distally of the retained stent graft. 
     Alternatively the balloon guide is a separate guide wire extending through the sheath lumen and the balloon catheter including the inflatable balloon is introduced onto the balloon guide after deployment of the stent graft. Alternatively the balloon catheter including the inflatable balloon may be carried on the separate guide wire distally of the retained stent graft during introduction. 
     In an alternate form the invention resides in a stent graft introducer comprising guide wire catheter, a nose cone dilator on the proximal end of the guide wire catheter, a distally opening capsule on the nose cone dilator, a sheath coaxially around the guide wire catheter and spaced apart therefrom to define an annular sheath lumen therein, a stent graft retained in the sheath lumen distally of the capsule, the stent graft comprising a proximally extending exposed stent and the proximally extending exposed stent being received and retained in the capsule of the nose cone dilator, a balloon catheter mounted coaxially onto the guide wire catheter and able to be moved therealong, during deployment the balloon catheter being positioned distally of the stent graft, whereby upon completion of deployment of the stent graft by retraction of the sheath and advancement of the nose cone dilator to remove the capsule from the proximally extending exposed stent, a balloon catheter including an inflatable balloon thereon can be advanced along the guide wire catheter at least partially into the nose cone whereby the balloon can be inflated therein and the nose cone dilator and the inflated balloon retracted such that the inflated balloon docks into the sheath whereby provide a smooth transition from the nose cone to the sheath for retraction of the stent graft introducer through the deployed stent graft. 
     It will be seen that by this invention there is provided an arrangement by which a balloon can be introduced at least partially into the capsule of an introducer after deployment of the stent graft and the balloon inflated until it is approximately the same diameter as the capsule. During retraction the balloon will act as a fairing to prevent the capsule engaging against the previously introduced stent graft until such time as the capsule is fully retracted or retracted sufficiently into an introducer sheath that the whole device can be withdrawn successfully. 
     As discussed above the balloon catheter and inflator balloon can be carried on the stent graft introducer distally of a stent graft during the introduction process and advanced when it is required to be used to assist with docking of the capsule. 
     Alternatively the balloon catheter can be introduced through a hemostatic seal on the introducer over the separate guide wire and advanced into the nose cone and inflated as discussed above. 
     This then generally describes the invention but to assist with understanding reference will now be made to the accompanying drawings which show in a stylised form preferred embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       In the drawings: 
         FIGS. 1A to 1E  show schematically a first embodiment of the invention; 
         FIGS. 2A to 2D  show an alternative embodiment of the invention; 
         FIG. 3  shows one embodiment of stent graft introducer incorporating a docking balloon arrangement according to the present invention; 
         FIG. 4  shows detail of the handle and manifold section of the embodiment shown in  FIG. 3 ; and 
         FIG. 5  shows the embodiment of  FIG. 3  after release of a stent graft and partial deployment of the docking balloon. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A to 1E  show in a stylised manner the operation of a docking balloon arrangement according to one embodiment of the invention. 
     In this embodiment, as shown in  FIG. 1A , the stent graft introducer has a nose cone dilator  8  with a distally facing capsule  18  (shown in section in  FIG. 1A ) mounted onto a guide wire catheter  24 . The guide wire catheter passes through the outer sheath  6 . An auxiliary guide wire  30  which extends substantially parallel to the guide wire catheter  24  and extends into the capsule  18  and is fixed inside the capsule and terminates at point  27 . The auxiliary guide wire  30  extends through the sheath  6  and haemostatic seal  124  (see  FIGS. 3 and 4 ) of the introducer. 
     After the stent graft has been deployed, the introducer is as shown in  FIG. 1A . At this stage, if the nose cone dilator  8  with capsule  18  is retracted to dock with the sheath  6  to enable their retraction together then the distal edge  29  of the capsule  18  could catch against portions of stents within an introduced stent or stent graft and cause the stent or stent graft to be dislodged. Similarly, if the sheath  6  is advanced so that the sheath docks with the capsule then the leading edge  6   a  of the sheath  6  could catch against portions of stents within an introduced stent graft and cause the stent graft to be dislodged. It is necessary to have an arrangement for providing a fairing to prevent engagement with the stents of the stent graft. 
     As shown in  FIG. 1B  a balloon catheter  96  has been introducer over the auxiliary guide wire  30  through the hemostatic seal (not shown). The balloon catheter  96  includes a inflatable balloon  98 . 
     The balloon catheter  96  and balloon  98  are advanced along the auxiliary guide wire  25  until its proximal end  98   a  is received within the capsule  18  as shown in  FIG. 1C . The balloon  98  is then inflated as shown in  FIG. 1D  until it is substantially the same diameter as the capsule  18 . 
     The nose cone  8 , capsule  18  and balloon  98  can then be retracted until the distal end  98   b  of the balloon  98  is engaged within the sheath  6  as shown in  FIG. 1E  and then the entire introducer device can be retracted without potential problems of engagement against stents of an already deployed stent graft. Alternatively the nose cone dilator  8 , capsule  18 , balloon  98  and guide wire catheter  24  can all be withdrawn leaving the sheath  6  in place. 
       FIGS. 2A to 2D  show an alternative embodiment of docking arrangement according to the present invention. 
       FIG. 2A  shows a schematic view of part of a stent graft introducer. The stent graft introducer includes a guide wire catheter  2  which extends from outside the body of a patient in use to a proximal end  4  upon which is mounted a nose cone dilator  6  and a distally facing capsule  8 . A sheath  10  surrounds a the guide wire catheter. At the stage shown in  FIG. 2A  a stent graft (not shown) has been deployed and the introducer is ready to be withdrawn. 
     At this stage, if the nose cone dilator  6  with capsule  8  is retracted to dock with the sheath  10  to enable their retraction together then the distal edge  12  of the capsule  8  could catch against portions of stents within an introduced stent or stent graft and cause the stent or stent graft to be dislodged. Similarly, if the sheath  10  is advanced so that the sheath docks with the capsule then the leading edge  22  of the sheath  10  could catch against portions of stents within an introduced stent graft and cause the stent graft to be dislodged. It is necessary to have an arrangement for providing a fairing to prevent engagement with the stents of the stent graft. 
     According to this embodiment of the invention, therefore, a balloon catheter  14  including an elongate catheter  16  and an inflatable balloon  18  is advanced over the guide wire catheter until, as shown in  FIG. 2B , the proximal end of the inflatable balloon  18  is received into the capsule  8 . The balloon  18  is formed from a non-compliant material such that when inflated it forms a selected size and shape and will not normally expand beyond that size. The desired size and shape is approximately sausage shape with a diameter approximately the same as the capsule on the nose cone dilator. 
       FIG. 2C  shows the balloon  18  inflated until it is substantially the same size as the outer diameter of the capsule  8 . At this stage the balloon  18  presents a rounded distal end  20  which will not engage deleteriously with the stents of a stent graft. 
     The balloon catheter, balloon nose cone dilator and capsule can then be withdrawn until the distal end  20  of the balloon  18  is received in the proximal end  22  of the sheath  10  as shown in  FIG. 2D . 
     At this stage if it is desired to leave the sheath  10  in place for subsequent deployment of stent grafts through the sheath the balloon  18 , capsule  8  and nose cone  6  can be withdrawn through the sheath or alternatively the sheath as well can be withdrawn to completely retract the introducer and its components from the vessel of the human or animal body. 
       FIG. 3  shows an alternative embodiment of a multi port stent graft introducer incorporating a docking balloon arrangement according to the present invention.  FIG. 4  shows in more detail the manifold and handle portion  102  of the delivery device shown in  FIG. 3 . 
     The introducer device  100  shown in  FIG. 3  comprises a handle and manifold assembly  102  and introduction portion  104  intended to be deployed into the patient. The introduction section  104  includes an outer sheath  106  extending from an outer sheath manipulator  108  to a nose cone dilator  110 . A stent graft is retained within the outer sheath  106  in the region  107  just distal of the nose cone dilator  110 . 
     The outer sheath manipulator  108  is positioned over an inner sheath  112  which extends back and is fastened to the manifold  114 . The inner sheath  112  extends proximal at least to a forward most position of the outer sheath manipulator  108  and preferably within the outer sheath to just distal of the stent graft retained within the outer sheath  106 . The manifold  114  has a proximal end  114   b  to which is connected the outer sheath  112  and four access ports at its distal end  114   a . Access port  116  is for a first access sheath  118 . Access port  120  is for a second access sheath  122 . A third access port  124  is for a docking balloon catheter  126 . 
     A fourth port  128  provides access to the handle  130  which includes trigger wire release mechanisms as discussed below. 
     The access sheath  118  extends to a haemostatic seal  132  through which extends the dilator  134 . On the dilator  134  is a dilator haemostatic seal  136  through which extends an indwelling guide wire  138 . 
     The access sheath  122  extends to a haemostatic seal  140  through which extends the dilator  142 . On the dilator  142  is a dilator haemostatic seal  144  through which extends an indwelling guide wire  146 . 
     The use of access sheaths  118  and  122  is discussed in co-pending U.S. patent application entitled “Multiport Delivery Device” (Ser. No. 11/807,878 filed May 30, 2007) the teaching of which is incorporated herein in its entirety. 
     The auxiliary balloon guide wire  154  extends through the balloon catheter haemostatic seal  152  and the inner and outer sheaths  112  and  106  proximally to the nose cone dilator  110  and is fastened to the nose cone dilator  110  within the capsule  117 . The balloon catheter  126  extends through balloon catheter haemostatic seal  124  and the inner and outer sheaths  112  and  106  proximally to just distal of the region  107  where the stent graft is carried. The balloon catheter has a non-compliant balloon  127  at its proximal end. The balloon catheter  126  includes an inflation lumen (not-shown) through which inflation medium can be supplied to the balloon  127  via inflation port  150 . 
     The handle assembly  130  includes trigger wire release mechanisms as follows. Trigger wire release  162  is for the diameter reducing ties on a stent graft carried on the delivery device, trigger wire release  160  is for the guide wire retention release wire (not shown). Trigger wire release  164  is for the retention trigger wire for a stent graft exposed stent in a distally facing capsule on the nose cone dilator  110 . Trigger wire release mechanism  166  is for the distal end of the stent graft. 
     A pin vice  170  is at the rear of the handle  130  and the guide wire catheter  172  for the introducer device extends through the pin vice  170  and is locked for movement with respect to the handle  130  by the pin vice. The guide wire catheter  172  terminates in a syringe point  174  to enable flushing liquid and radiopaque medium to be deployed through the delivery device. 
       FIG. 5  shows the delivery device of  FIGS. 3 and 4  after delivery of a stent graft and before retraction of the nose cone dilator. The vasculature into which the stent graft has been delivered is not shown for reasons of clarity. At this stage each of the access sheaths  118  and  122  (see  FIG. 3 ) have been withdrawn and the trigger wire release mechanisms  162 ,  160 ,  164  and  166  (see  FIG. 3 ) have also been withdrawn. Also at this stage the stent graft  109  would be engaged against the wall of the vessel into which it has been deployed but the exposed stent  111  and the internal stents  113  could be engaged by the either the distal edge  115  of the capsule  117  if that was retracted to the sheath or the proximal edge  106   a  of the outer sheath  106  if that was advanced to the capsule. 
       FIG. 5  shows that the balloon catheter  126  has been advanced over the guide wire  154  until the proximal end  127   a  of the balloon  127  has been received in the capsule  117  and the balloon has been inflated until it is approximately the same diameter as the nose cone dilator  117  and the outer sheath  106 . 
     The nose cone dilator  117 , the balloon  127  and balloon catheter  126  can then all be withdrawn together until the distal end  127   b  of the balloon  127  is received in the proximal end  106   a  of the outer sheath  106 . Then either the entire delivery device  100  can be withdrawn or the nose cone dilator  117 , the balloon  127  and balloon catheter  126  can then all be withdrawn together until they are received in the inner sheath  112  and then these along with the handle assembly  102  can be withdrawn leaving the outer sheath  106  in place for subsequent endovascular procedures therethrough. 
     Throughout this specification various embodiments of the invention have been discussed but the invention is not limited to any one of them but may reside in two or more combined together in part or in whole. The examples are given for illustration only and not for limitation.