Abstract:
A delivery catheter for providing the percutaneous delivery of a plurality of vascular stents. One or more stops are provided in the delivery catheter between each of the plurality of stents. The stops be radiopaque to assist in deploying the stents at desired locations within the vasculature of a patient.

Description:
FIELD OF INVENTION  
       [0001]    The present invention relates to the field of medical devices, and more particularly to a device for the delivery of multiple in vivo implant devices. 
       DESCRIPTION OF RELATED ART 
       [0002]    Vascular disease is a leading cause of premature mortality in developed nations, often presenting as a vascular aneurysm. A vascular aneurysm is a localized dilation of a vessel wall, due to thinning or weakness of the wall structure, or separation between layers of the vessel wall. If untreated, the aneurysm may burst and hemorrhage uncontrollably. Aneurysms are particularly dangerous and prevalent in the aorta, because the aorta supplies blood to all other areas of the body, and because the aorta is subject to particularly high pressures and stresses accordingly. Rupture of an aortic aneurysm is the 15 th  leading cause of death the United States, afflicting 5% of older men. 
         [0003]    It is known to treat vascular aneurysms surgically where blood pressure control medication is unsuccessful at arresting growth of the aneurysm. Surgery often involves the insertion of a vascular stent graft to exclude the aneurysm and carry blood past the dilated portion of the vessel, relieving the pressure on the aneurysm. Other applications for the treatment of vascular disease is the use of a stent to open an occluded vessel, commonly a coronary artery. Such stents may include a coating designed to release a pharmaceutical compound into the bloodstream at a controlled rate. 
         [0004]    Moreover, it would be advantageous to design a stent graft that is collapsible to facilitate percutaneous insertion by minimally invasive surgical techniques. Additionally, percutaneous insertion requires the design and development of a delivery apparatus that can effectively position and deploy the vascular stent. 
         [0005]    It is often advantageous to provide multiple stents to support a vessel. For example, a vessel may be subject to multiple blockages along its length. Alternately, it often enhances the flexibility of the stent and improves stent placement accuracy to provide plural serial stents rather than a single stent of equivalent length. Therefore, an efficient delivery apparatus for plural in vivo implant devices, such as prosthetic stents, is desired in the art. 
       BRIEF SUMMARY OF THE INVENTION  
       [0006]    Therefore, in order to overcome these and other deficiencies in the prior art, provided according to the present invention is an apparatus for the percutaneous delivery of plural segmented vascular stents. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]    These and other features, benefits, and advantages of the present invention will be made apparent with reference to the following detailed description, appended claims, and accompanying figures, wherein like reference numerals refer to like structures across the several views, and wherein: 
           [0008]      FIG. 1  illustrates a schematic version of a delivery catheter according to a first embodiment described herein. 
           [0009]      FIG. 2  illustrates a distal end of the delivery catheter of  FIG. 1 . 
           [0010]      FIG. 2A  illustrates a distal portion of the delivery catheter after a first distal stent has been deployed according to the first embodiment described herein. 
           [0011]      FIG. 3  illustrates a cross-sectional view of a distal end of a delivery catheter according to the first embodiment described herein. 
           [0012]      FIG. 4  illustrates a second embodiment of a delivery catheter according to the description provided herein. 
           [0013]      FIG. 5  illustrates a third embodiment of a delivery catheter according to the description provided herein. 
           [0014]      FIG. 6  illustrates a fourth embodiment of a delivery catheter according to the description provided herein. 
           [0015]      FIG. 7  illustrates a fifth embodiment of a delivery catheter according to the description provided herein. 
           [0016]      FIG. 8  illustrates a sixth embodiment of a delivery catheter according to the description provided herein. 
           [0017]      FIG. 9  illustrates a seventh embodiment of a delivery catheter according to the description provided herein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to  FIG. 1 , illustrated schematically is a delivery catheter, generally  10 , according to the present invention. Delivery catheter  10  has a first handle  12  at a proximal end in communication with a guide wire (not shown) extending axially through the delivery catheter  10 . A second handle  14  is in communication with an inner shaft  20  of the delivery catheter  10 . An insertion valve  18 , preferably a tuohy-borst valve, is in communication with an outer sheath  16  of the delivery catheter  10 . Each of the guide wire, the inner shaft  20 , and outer sheath  16  are independently axially displaceable relative to one another, by movement of first and second handles  12 ,  14 , with respect to one another and/or to the insertion valve  18 . 
         [0019]    Referring now to  FIG. 2 , illustrated is a distal end, generally  22 , of the delivery catheter  10  for  FIG. 1 . Inner shaft  20  ends at a distal tip  24 . Outer sheath  18  is preferably connected with the distal tip  24 , to enable the delivery catheter  10  to rotate as a unit upon insertion and/or to present a continuous outer surface of the delivery catheter  10 , thereby reducing resistance to insertion. One or more prosthetic stents  26  are crimped, or reduced in diameter from a fully deployed diameter, onto inner shaft  20  near the distal tip  24 . A radiopaque stent marker  28  surrounds the inner shaft  20  between adjacent stents  26   a ,  26   b , thereby radiographically locating, for example by fluoroscopy, the one or more stents  26   a ,  26   b  for in vivo delivery and implantation. Additionally, the delivery catheter  10  may include distal radiopaque marker  30  that moves together with the distal tip  24 , and proximal radiopaque marker  32  that is secured in axial position along the inner shaft  20 . 
         [0020]    The stents  26  are preferably self-expanding, and/or comprise a shape memory material, comprising Nitinol or some alloy thereof. In this exemplary embodiment, stent  26   a  is a covered stent, or one having a coating to, for example, enhance biocompatibility and/or to elute a pharmaceutical compound into the body. By contrast, stent  26   b  is an uncovered or bare stent. Once positioned as desired by the surgeon, the stents  26   a ,  26   b  are deployed individually, by withdrawing the outer sheath  16  from over the stents  26   a ,  26   b , which are then free to expend in the vascular environment. 
         [0021]    Preferably, the stents  26   a ,  26   b  are deployable individually, and only one stent need be deployed at a time. Referring now to  FIG. 2A , after a first distal stent is deployed, in this case covered stent  26   a , the distal tip  24  may be withdrawn to meet the outer sheath  16 . Stent marker  28  is preferably free-floating over inner shaft  20 . Therefore as the distal tip  24  is withdrawn proximally, the stent marker  28  is positioned adjacent a distal end of outer sheath  16 , approximately co-located with distal marker  30 . Proximal marker  32  having been advanced distally relative to the outer sheath  16  with the deployment of the first distal stent, i.e., covered stent  26   a , said proximal marker  32  remains immediately proximal to the bare stant  26   b.    
         [0022]    Turning then to  FIG. 3 , illustrated schematically in partial cross-section is a delivery catheter, generally  100 , and more specifically a distal end thereof, generally  102 . An outer sheath  104  has an axial lumen  106  therethrough, and extends to a distal tip  108 . Outer sheath  104  is preferably connected with the distal tip  108 , to enable the delivery catheter  100  to rotate as a unit upon insertion and/or to present a continuous outer surface of the delivery catheter  100 , thereby reducing resistance to insertion. Inner shaft  110  extents through axial lumen  106  to terminate at the distal tip  108 . Preferably, inner shaft  110  has an axial lumen (not shown) running therethrough, to admit a guide wire to assist in inserting the delivery catheter  100 . 
         [0023]    A plurality of implants  112 , for example vascular or other stents, are crimped, i.e., reduced in diameter from a fully deployed diameter to fit within axial lumen  106  for insertion and delivery, to the inner shaft  110 . Between each implant  112  is an axial stop  114 , which are either free-floating, i.e., axially displaceable over the inner shaft  110  within the axial lumen  106 , or secured to the inner shaft  110 . A proximal stop  116  is secured to the inner shaft  110  proximally from all implants  112 , and limits the axial motion of implants  112  and/or stops  114  between itself and the distal tip  108 . 
         [0024]    Additionally, the stops  114  may vary in width, either axially, radially, or both, to counteract the stored compressive energy in the delivery catheter  100  during the deployment of successive implants  112 . Accordingly, the deployment force required of each implant  112  is more uniform over the course of the procedure, which assists in the more precise and accurate control of deployed position. 
         [0025]    Referring now to  FIG. 4 , illustrated is an alternate embodiment of a delivery catheter, generally  200 . In this embodiment, the stops  214  between each of the implants  112  are radiopaque. The radiopaque stops  214  assist in by radiographically locating, for example by fluoroscopy, the one or more implants  114  for precise control of deployment. 
         [0026]    Referring now to  FIG. 5 , illustrated is an alternate embodiment of a delivery catheter, generally  300 . In this embodiment, the stops  314  between each of the implants  112  are proximally tapered, i.e., they are tapered from a narrower diameter on a proximal side  314   a  to a wider diameter on a distal side  314   b . The proximally tapered stops  314  assist may be radiopaque or non-radiopaque. 
         [0027]    It is known that self-expanding implants, such as implants  114  have a tendency to ‘jump’, or to move axially from the open end of the outer sheath  104  in the process of expanding to their deployed diameter, as the outer sheath  104  is retracted. The tapered stops  314  assist in the deployment of implants  114  because they allow the implant to pass over the stop  314  with a reduced risk of catching the implant  114  on the stop  314 . Therefore, the implant  114  is deployed more consistently without unexpected catching, improving the precision and accuracy of the deployment position. 
         [0028]    Referring now to  FIG. 6 , illustrated is an alternate embodiment of a delivery catheter, generally  400 . In this embodiment, implants  412  are provided with integral radiopaque markers  412   a , preferably more than one, and preferably distributed over the circumference of the implant  412  at both the proximal and distal ends thereof. In this embodiment, stops  414  are non-radiopaque, to avoid interference with the imaging of the radiopaque markers  412   a  on the implants  412  themselves. 
         [0029]    Referring now to  FIG. 7 , illustrated is an alternate embodiment of a delivery catheter, generally  500 . In this embodiment, the stops  514  between each of the implants  112  are proximally tapered, as in the embodiment of  FIG. 5 . Moreover, the proximally tapered stops  514  are non-radiopaque. Implants  412  have radiopaque markers  412   a , as described with reference to  FIG. 6 . 
         [0030]    Referring now to  FIG. 8 , illustrated is an alternate embodiment of a delivery catheter, generally  600 . In this embodiment, the stops  614  between each of the implants  112  are of generally constant diameter. Moreover, the constant diameter stops  614  are radiopaque, as described with reference to the embodiment of  FIG. 4 . Implants  412  have radiopaque markers  412   a , as described with reference to  FIG. 6 . 
         [0031]    Referring now to  FIG. 9 , illustrated is an alternate embodiment of a delivery catheter, generally  700 . In this embodiment, the stops  314  between each of the implants  412  are proximally tapered and radiopaque, as described with reference to  FIG. 5 . Implants  412  have radiopaque markers  412   a , as described with reference to  FIG. 6 . 
         [0032]    Accordingly, it will be appreciated from  FIGS. 4-9  that the axial stops may be of generally constant diameter or tapered, preferably proximally tapered. Axial stops may be radiopaque or non-radiopaque. The implants themselves may or may not have radiopaque markers. Moreover, any of these features may be used or omitted in any permutation as desired. 
         [0033]    The delivery catheter  100  having a central lumen (not shown) for a guide wire will by recognized by those skilled in the art as an over-the-wire type configuration. Alternately, however, the distal tip  108  of the delivery catheter  100  may include an abbreviated passage to accept the guide wire, as part of a so-called rapid-exchange design as is known in the art. Accordingly, the delivery catheter  100  need not be threaded over the entire length of the guide wire, and the guide wire can be shorter. Moreover, using a rapid-exchange design obviates the need for a central lumen to admit the guide wire through all or most of its length. Accordingly, the overall diameter of the delivery catheter can be advantageously reduced. Since the point of connection in the rapid-exchange design is distal of the implants  114 , the guide wire would necessarily be outside the implants after deployment, to be subsequently withdrawn. 
         [0034]    The present invention has been described herein with reference to certain exemplary or preferred embodiments. These embodiments are offered as merely illustrative, not limiting, of the scope of the present invention. Certain alterations or modifications may be apparent to those skilled in the art in light of instant disclosure without departing from the spirit or scope of the present invention, which is defined solely with reference to the following appended claims.