Abstract:
A prosthetic delivery device is adapted for introducing a stent within a patient&#39;s vasculature through a reverse deployment procedure, beginning at a proximal location and finishing at a distal location. The device comprises: a guide tube, a rotation tube, and an outer tube. The guide tube threadably receives the rotation tube thereon. The rotation tube comprises a sheath rotatably secured at one end to overhang over a portion of the outer tube, which is received over a portion of the rotation tube, and which is fixedly secured to the guide tube. Rotating the rotation tube causes its translation relative to the outer tube. A stent crimped to be disposed beneath the sheath is forced to deploy proximally by relative movement of an annular deployment ring on the outer tube. A key on the outer tube is received within a key way of the sheath to prevent its rotation.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority on U.S. Provisional Application Ser. No. 61/519,238, filed on May 18, 2011, the disclosures of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to improvements in methods and apparatus used in the deployment of stents, and more particularly to apparatus which is capable of installing such devices with high fidelity in proximal relation to specific intraluminal locations. 
       BACKGROUND OF THE INVENTION 
       [0003]    The blood vessels and arteries, lymphatic vessels, the ureters of the urinary system, and other ducts within the human body, are subject to degradation. Weaknesses in the walls of these ducts may result from a number of different reasons, such as a ureter being compromised by a kidney stone, or a blood vessel weakening due to atherosclerosis and aging. A minimally invasive surgical treatment for weakened, aneurysmal, or ruptured vessels may comprise the introduction of prosthesis within the lumen. The prosthesis, which often may be a stent, serves to restore some or all of the functionality lost through the deterioration of the vessel and/or bolster the duct&#39;s integrity at the site of weakness. 
         [0004]    There are many devices that have been developed to introduce a stent into the inner open space or “lumen” of these vessels and ducts. A representative example of these devices is shown by the invention in U.S. Pat. No. 7,867,268 to Shelso, titled, “Stent Delivery System for Self-Expanding Stent.” In Shelso, as with virtually most of these devices, a catheter assembly comprises an outer tube, into which a self-expanding stent is loaded, and also comprises a slidable inner tube connected to a tip. The catheter is inserted into the vessel lumen and advanced to the site that is slated to receive the stent. Once properly positioned, the outer tube is backed outward relative to the inner tube with the result that the stent is introduced beginning from the far end—the distal end—and progressively released out from the outer tube to self-expand to contact the vessel wall, until the proximal end of the stent is similarly released and installed. The catheter of the delivery device may then be removed. 
         [0005]    A major drawback of all of these devices is that they install the stent in the distal-to-proximal direction. These are several scenarios where the typical distal-to-proximal deployment is highly undesirable, and a means of positioning the stent to have one end at an exact proximal location-requiring a proximal-to-distal deployment—would be extremely advantageous, because placement of the stent at such a proximal location is critical in certain scenarios. Some examples of such scenarios are: where the self-expanding stent is to be deployed in proximity to a location where a side branch originates and the side branch is not to be covered; where a stent is needed to be deployed to overlap another previously installed stent more proximally; and to cover the Ostia of a lumen. The invention herein comprises a new apparatus and corresponding method to achieve a reverse stent deployment installation, to ensure critical proximal stent positioning. 
       SUMMARY OF THE INVENTION 
       [0006]    Throughout this specification, when discussing the blood vessels and other types of ducts, the term distal with respect to the prosthesis refers to the end of the prosthesis furthest away from the position of the medical personnel operating the device. Similarly, the term proximal means the end of the prosthesis, which, when implanted, would be nearest to the medical personnel. Usage of the terms “distal” and “proximal” are also used herein to relatively describe respective ends or portions of different parts/features of the disclosed device, by having the same positional reference with respect to the medical personnel. 
         [0007]    A prosthetic delivery device is disclosed herein, being for use in introducing a stent within a lumen through a reverse deployment procedure, with deployment beginning at a proximal end location and finishing at a distal end location. The prosthetic delivery device may comprise an inner tube assembly, a rotation tube assembly, and an outer tube assembly. The rotation tube assembly may be threadably engaged with the inner tube assembly. The outer tube assembly may be received over the rotation tube and be fixed relative to the inner tube. The rotation tube may comprise a sheath that concentrically overlays a portion of the outer tube assembly, beneath which a self-extending stent may be positioned. When the rotation tube is rotated to translate relative to both the inner tube assembly and the outer tube assembly, the stent is exposed and deploys beginning at the proximal location, and ending at the distal location. A guide wire may extend through the inner tube from one end and out of the other end. One or more flush tubes may be used on each of the tube assemblies, where the flush tube terminates in a female syringe adapter that permits threadable attachment of a syringe thereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a profile view of the stent delivery apparatus of the current invention, with the delivery sheath shown in the un-deployed position to be overhanging a portion of the outer tube, and with a stent stowed therebetween. 
           [0009]      FIG. 1A  is the profile view of the stent delivery apparatus of  FIG. 1 , enlarged to show the interface between outer tube and the sheath at the end of the distal end of the stent. 
           [0010]      FIG. 1B  is the profile view of the stent delivery apparatus of  FIG. 1 , but shown with the delivery sheath in the fully deployed position, and with a stent prior to being loaded onto the delivery platform of the outer tube, and with a portion of the loaded stent just prior to being crimped. 
           [0011]      FIG. 2  is the stent delivery apparatus of  FIG. 1 , with the delivery sheath being in a partially deployed position and a portion of the stent having self-expanded beginning at the proximal edge of the desired intraluminal location, and with a portion of the stent remaining stowed between the delivery sheath and the outer tube. 
           [0012]      FIG. 2A  is the stent delivery apparatus of  FIG. 2 , shown with the sheath fully deployed, with the stent having self-expanded completely to support the vessel wall beginning at the proximal edge of the desired intraluminal location and ending at a distal location, and without the threading on the guide tube to make the graduated markings more visible. 
           [0013]      FIG. 3  is a cross-sectional view through the three tubes of the apparatus, being taken at a location where the stent is stowed. 
           [0014]      FIG. 4  is the view of  FIG. 2A  with the stent fully installed, and the stent-delivery apparatus having been removed. 
           [0015]      FIG. 5  is a side view of the inner guide tube assembly of the current invention. 
           [0016]      FIG. 6  is a side view of the rotation tube assembly of the current invention. 
           [0017]      FIG. 7  is a side view of the outer tube assembly of the current invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]      FIG. 1  shows a first embodiment of a prosthetic delivery device  10 , being particularly adapted for introducing a stent within a lumen of a vessel, through a deployment procedure that is reversed with respect to conventional deployment, where deployment herein begins with the stent self-expanding at a desired proximal end location, and finishing at a distal end location. The main component parts of the prosthetic delivery device  10  comprise an inner guide tube assembly  20 , a rotation tube assembly  40 , and an outer tube assembly  60 , each of which is shown individually within  FIGS. 5 ,  6 , and  7  respectfully. 
         [0019]    The inner guide tube assembly  20  ( FIG. 5 ) may have a first end  21  and a second end  22 . The inner tube assembly  20  may comprise a flexible hollow tube  23  being of sufficient length to reach the sites that are typically the area targeted to receive a stent. A region  24  of the exterior of the inner tube  20 , being proximate to the first end  21 , may have external threading  25  located thereon. The external threading  25  may be coarse threading, or may be fine threading, as required for a particular type of prosthetic/stent installation being performed. Being secured to the first end  21  of inner tube  20  may be a lock fitting  26 , which may extend radially outward from the tube  23 , and may comprise a cylindrical shape. The lock fitting  26  may be attached to the tube  20  using any suitable manufacturing means available within the art, including, but not limited to, adhesive bonding, swaging, etc. The lock fitting  26  may also be integrally formed with the tube  20 . 
         [0020]    The lock fitting  26  may serve multiple functions, which may include limiting the travel of the rotation tube, as discussed hereinafter. In addition, the lock fitting  26  may support a flush tube  31  that may protrude from a portion of the lock fitting. The flush tube  31  may have one end interconnecting with the interior conduit (inner lumen) of tube  23  to be in fluid communication therewith, and may have a female syringe adapter  27  secured at the other end. The syringe adapter  27  may comprise female threading that permits a standard syringe to be screwed thereon to permit flushing of the inner tube  20 , to ensure removal of air and/or contaminants therein to prevent them from entering the patient&#39;s vasculature. The syringe adapter  27  may be constructed in accordance with U.S. Pat. No. 4,588,403 to Weiss for a “Vented Syringe Adapter Assembly,” the disclosures of which are incorporated herein by reference, or it may be constructed per any other suitable syringe adapter known in the art. 
         [0021]    The inner lumen of the tube  23  of tube assembly  20  may be appropriately sized so that a guide wire  80  may be slidably received there through. During the prosthetic/stent installation procedure, the guide wire  80  may initially be advanced through the inner lumen of tube  23  to extend out from the second end  22  of the tube, and guide wire  80  may then be maneuvered into the patient&#39;s vasculature to a point which is near to, or slightly beyond, the region that is to receive the stent. The guide wire may furthermore function as described within U.S. Pat. No. 4,787,884 to Goldberg for “Ureteral Stent Guidewire System,” and within U.S. Pat. No. 6,280,465 to Cryer for “Apparatus and Method for Delivering a Self-Expanding Stent on a Guide Wire,” with the disclosures of each being incorporated herein by reference. 
         [0022]    The second end  22  of tube  23  of guide tube assembly  20  may comprise a nose cone  29 . The nose cone  29  may generally have a diamond-shaped profile, as seen in  FIG. 5 , the forward facing portion of which may serve to create an aerodynamic tip  29   b  to reduce friction and resistance while moving the delivery device  10  into and out of a vessel lumen. The nose cone  29  may be attached to the tube  23  using any suitable manufacturing means known in the art, including, but not limited to, adhesive bonding, swaging, etc. The nose cone  29  may alternatively be integrally formed with the tube  23 . The nose cone  29  may thus extend radially outward from the tube  23  of inner tube assembly  20 . The rear or proximal end  29 A of the nose cone  29  may serve to limit travel of the rotation tube  40  at a second position, as discussed hereinafter (see  FIG. 1B ). 
         [0023]    The rotation tube assembly  40  ( FIG. 6 ) may have a first end  41  and a second end  42 . The rotation tube assembly  40  may comprise a hollow tube  43 , with a region  44  therein having internal threading  45 , which may preferably begin at the first end  41 , and be selected to threadably engage with the external threading  25  of inner tube  20 . The first end  41  of rotation tube assembly  40  may comprise a graspable rotator member  46  being attached thereto, with the graspable rotator extending radially outward from the rotation tube  43 . The graspable rotator member  46  may be attached to the tube  23  using any suitable manufacturing means known in the art, including, but not limited to, adhesive bonding, swaging, etc. The graspable rotator member  46  may alternatively be integrally formed with the rotation tube assembly  40 . The graspable rotator  46  may serve to provide the tube with a larger diameter feature, which may thereby provide the user of the delivery device with a more ergonomic means of physically grasping the rotation tube  40  to cause its rotation. The end of the graspable rotator  46  coinciding with the first end  41  may have a cylindrical recess  46 R therein, which may be of sufficient depth to receive a portion of the cylindrical lock fitting  26 . 
         [0024]    The second end of the rotation tube  40  may comprise a rotator cone  48  from which a sheath  49  may extend in the proximal direction. The sheath  49  may be connected to the rotator cone using a swivel joint  51 , which may permit the rotator cone  48  of the rotation tube  40  to correspondingly rotate with tube  43 , without necessitating corresponding rotation of the sheath  49 . The swivel joint thus permits relative rotation between the sheath  49  and rotator cone  48 . The swivel joint may be constructed similar to the “Swivel Head Cap Connector” of U.S. Pat. No. 5,372,532 to Robertson, or the “Hose Swivel” of U.S. Pat. No. 5,316,351 to Czimny, or the “Swivel Connector” of U.S. Pat. No. 4,955,749 to Panovie, with the disclosures of each being incorporated herein by reference. The sheath may extend from the rotator cone  48  back toward the first end  41 , and may be generally concentric with the generally cylindrical tube.  43 , but be offset therefrom to create a cylindrical gap into which the stent  100  ( FIGS. 1-4 ) may be inserted. The gap may therefore be calibrated to accommodate, in a clearance fit, the thicknesses of various different stents that may be desirably installed using the device. The stent  100 , in order to be self-extending, would be normally biased outward; therefore, the stent  100  may need to be preloaded inwardly to insert it into the cylindrical gap between the sheath  49  and the tube  43  of the rotation tube  40 , which is discussed in more detail hereinafter. 
         [0025]    The outer tube assembly  60  ( FIG. 7 ) may have a first end  61  and a second end  62 . The rotation tube assembly  60  may comprise a tube  63  that may preferably have a first portion comprising an outer cylindrical surface  63 A that begins at the first end  61 , and which transitions prior to reaching the second end  62 , into a second portion having an outer cylindrical surface  63 B, which may serve as a stent “platform.” Outer surface  63 B may have a diameter being slightly smaller than the diameter of outer surface  63 A, with this smaller diameter serving to accommodate clearance with the stent  100 . Located proximate to second end  62  of the outer tube assembly  60  may be an annular deployment ring  64  protruding radially out from the outer surface  63 B, which may serve to precipitate the deployment of the stent  100  out from the annular gap in the sheath  49  of the rotator tube  40 . The deployment ring  64  could be a solid protrusion extending radially outward from the outer tube, or may instead be a separated ring secured thereon, from which may protrude a plurality of soft bristles that may be used to gently urge the stent out from the beneath the sheath, without causing damage to the end of the stent during its deployment. 
         [0026]    The deployment ring  64 , as seen in  FIG. 1A , may protrude radially so as to maintain a slight clearance fit with the inner diameter of the sheath  49  of the rotator tube  40 . Alternatively, deployment ring  64  may protrude radially so as to engage the inner diameter of the sheath  49  of the rotator tube  40  in a very slight interference fit, to ensure contact with, and deployment of, the stent  100 . This interference fit may also serve to deter co-rotation of the swivel-mounted sheath  49 , when the rotation tube  40  is being rotated to release the stent  100 . Rather than using this interference fit to deter co-rotation of the sheath  49 , a key  68 K protruding from the second end  62  of outer tube  60  ( FIG. 7 ) may be slidably received within a corresponding keyway  49 K on the inside surface of the sheath ( FIG. 6 ) to more positively limit the motion of the swivel-mounted sheath  49  to be only translational motion ( FIG. 2 ), despite the rotational and translation motion that may be experienced by the rotator cone  48 . 
         [0027]    Located at the first end  61  may be an annular hemostatic seal member  65 , which may serve to seal the outer tube  60  with respect to the rotation tube  40 . The annular seal member  65  may be made of any suitable sealing material, including, but not limited to, an ethylene propylene elastomer. Located proximate to the first end  61  may be a flush tube  66 , which may have one end interconnecting with the interior conduit of tube  63 , and may have a female syringe adapter  67  at the other end. The syringe adapter  67  may be similar to female syringe adapter  27 , and may comprise female threading that permits a standard syringe to be screwed thereon to permit flushing of the outer tube  60 . 
         [0028]    The assembled prosthetic delivery device  10  with a self-expanding stent  100  preloaded and inserted therein, is shown in  FIG. 1 . The outer tube assembly  60  may be slidably received over the rotation tube and be secured to the inner tube assembly  20  using suitable mechanical fasteners  68 . The mechanical fasteners  68  may be installed with a sealant material so as to be sealed with respect to the inner tube  23  and with respect to the outer tube  63   a.  To permit free unrestricted movement of the rotation tube assembly  40 , the rotation tube  43  may comprise slotted openings  47  in the region on either side of the fasteners  68 . 
         [0029]    Rotating the rotation tube assembly  40  may cause it to correspondingly translate relative to both the inner tube assembly  20  and the outer tube assembly  60 , so that the recess  46 R in the graspable member  46  no longer receives the cylindrical lock fitting  26  at the first position, because the graspable member has translated slightly in the distal direction, as seen in  FIG. 1 . The sheath  49  similarly translates, and with continued rotating of the rotation tube assembly  40 , the nose cone  48  of the rotation tube assembly may eventually contact the proximal end  29   a  of the diamond-shaped nose cone  29  at the second end  22  of tube  23  of guide tube assembly  20 , to thereby limit travel of the rotation tube  40  at a second position, as seen in  FIG. 1B . 
         [0030]    With the rotation tube  40  being rotated to occupy this second position, the stent  100  may be loaded thereon in order to prepare a fully assembled prosthetic delivery device  10  that is ready to perform the prosthetic installation. The free-standing, self-expanded stent  100   E  in  FIG. 1B  is first loaded across the nose cone  29 , the nose cone  49 , and the sheath  49 , and onto the “platform” of outer surface  63 B, after which it may be preloaded inward for insertion beneath the sheath  49  of the rotation tube  40 . Insertion of the stent  100  beneath the sheath  49  may be done by manually crimping and causing a size reduction of the expandable stent, as had been done in the past, or by using a specially constructed device, such as the one shown by U.S. Pat. No. 7,992,273 to Austin for “Crimping Apparatus for Reducing Size of a Stent,” as well as by a device disclosed by one of the references cited therein, with the disclosures of each being incorporated herein by reference. As crimping of the stent  100   C  occurs, which is initially adjacent to the deployment ring  64 , the sheath  49  may be backed to overhang more of cylindrical surface  63 B and overhang the crimped portion of the stent, as the sheath moves back toward the first cylindrical surface  63 A, by counter-rotating the rotation tube assembly  40 . 
         [0031]      FIG. 2  shows the fully assembled prosthetic delivery device  10  having been advanced within a lumen  120  of a patient to the site requiring proximal-to-distal stent deployment, and with the self-expanding stent  100  initially expanding precisely at the desired proximal location  121 , being near a weakened region  120 W. Continued rotation of the rotation tube  40  may continue until the stent  100  is fully deployed at the distal end  122  within body lumen  120 , as seen in  FIG. 2A . The device  10  may then be removed from the lumen, which had then been reinforced by the stent  100 , as seen within  FIG. 4 . 
         [0032]    To assist the practitioner who is performing the stent deployment procedure, the inner tube  23  may contain graduated markings  28  that may be exposed, as the rotation tube assembly translates distally, in order to inform the practitioner as to the progress made in deploying the stent. In addition, the graduated markings  28  may transition into a series of graduated markings  28 G having a smaller spacing therebetween, to inform the practitioner as to when the sheath should be translated sufficiently so that the stent has been fully deployed, and also as to when the second end of the rotation tube is nearing contact with the rear portion of the nose cone  29 . Alternatively, or in addition to such markings  28 , completed travel of the rotation tube, at which time the stent should be fully deployed, may occur and be indicated by the second end  42  of the rotation tube contacting a rear portion of, or the proximal end  29   a  of, the nose cone  29 . 
         [0033]    The examples and descriptions provided merely illustrate a preferred embodiment of the present invention. Those skilled in the art and having the benefit of the present disclosure will appreciate that further embodiments may be implemented with various changes within the scope of the present invention. Other modifications, substitutions, omissions and changes may be made in the design, size, materials used or proportions, operating conditions, assembly sequence, or arrangement or positioning of elements and members of the preferred embodiment without departing from the spirit of this invention.