Abstract:
The present invention is a “rescue” catheter that is designed to be placed over a fixed wire stent delivery catheter after angiography reveals that an intimal dissection has occurred typically as an edge dissection either just proximal or just distal to the stent.

Description:
FIELD OF USE  
         [0001]    This invention is in the field of catheters that are used to treat an intimal dissection resulting from the placement of a stent into an artery such as a coronary artery.  
         BACKGROUND OF THE INVENTION  
         [0002]    In U.S. patent Ser. No. 09/444,104, incorporated herein by reference, a stent delivery catheter is described that has a fixed guide wire at its distal end. Although this system for delivering a stent into a vessel of the human body has the advantage of providing an extremely small outside diameter for easy insertion through even the narrowest of arterial stenoses, it does have a potential difficulty in for those few cases when an intimal dissection occurs after stent implantation. Specifically, if a separate guide wire is used during stent implantation, it can be kept in place after the stent delivery catheter is removed thus allowing insertion of a second stent delivery system over the guide wire to repair any intimal dissection. However, if the guide wire is fixed to the stent delivery catheter, it will be removed with the stent delivery catheter after the stent has been delivered. Without a guide wire through that portion of the artery where an intimal dissection has occurred, it can be extremely difficult to place a second stent delivery catheter to deliver a second stent to repair such an intimal dissection.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention is a “rescue” catheter that is designed to be placed over a fixed wire stent delivery catheter after angiography reveals that an intimal dissection has occurred typically as an edge dissection either just proximal or just distal to the stent. The present invention is also a method for using such a catheter to repair an intimal dissection. It should be understood that an intimal dissection that is in close proximity to the edge of an implanted stent is called an “edge dissection”.  
           [0004]    As previously stated, U.S. patent Ser. No. 09/444,104 describes a fixed guide wire stent delivery catheter with an extremely small outside diameter which can be used to deliver a stent through a very tight arterial stenosis. After the stent on the stent delivery catheter has been delivered into the arterial wall, the balloon would be deflated and the fixed guide wire stent delivery catheter would be left in place. Contrast medium would then be delivered to the site of the dilated stenosis to indicate if there is any arterial wall dissection. Such an intimal dissection would typically occur near the proximal or distal edge of the stent. In most cases, there will be no edge dissection, the stent delivery catheter would be removed from the body, and the stent implantation would be considered to be successfully completed.  
           [0005]    If, however, angiography with the contrast medium indicates that an edge dissection has occurred, then a second stent must be placed at the site of the dissection to restore normal blood flow. If a dissection occurs, the fixed guide wire stent delivery catheter would be left in place with its balloon deflated. The Luer fitting at the proximal end of the stent delivery catheter would then be cut off and a rescue catheter would be advanced over the stent delivery catheter.  
           [0006]    The rescue catheter would be advanced until its distal end extended beyond the site of the edge dissection. The fixed wire stent delivery catheter would then be pulled out of the body through the rescue catheter, and a conventional guide wire would be inserted through the rescue catheter. The rescue catheter would then be removed leaving the guide wire in place. A conventional stent delivery catheter would then be used to deliver a second stent to the site of the intimal dissection at the edge of the first implanted stent, thus repairing the dissection.  
           [0007]    Thus, an object of the present invention is a rescue catheter that is designed to be placed over a fixed guide wire stent delivery system if angiography indicates that an intimal dissection has occurred, the rescue catheter being designed for placement of a conventional guide wire through it so that a second stent delivery system can be advanced over the guide wire to deliver a stent to repair the intimal dissection.  
           [0008]    Another object of the present invention is a method for using a rescue catheter to treat an intimal dissection created by the delivery of a stent from a fixed guide wire stent delivery system.  
           [0009]    These and other important objects and advantages of this invention will become apparent from the detailed description of the invention and the associated drawings provided herein. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a side view of a prior art fixed guide wire stent delivery system shown with the stent mounted onto the balloon.  
         [0011]    [0011]FIG. 2 is a longitudinal cross section of the fixed guide wire stent delivery system with the stent shown delivered into an arterial stenosis, where the balloon is deflated and a distal intimal dissection has occurred.  
         [0012]    [0012]FIG. 3 is a side view of the rescue catheter that is adapted to pass through an intimal dissection.  
         [0013]    [0013]FIG. 4 is a longitudinal cross section of a distal portion of the rescue catheter at section  4 - 4  of FIG. 3.  
         [0014]    [0014]FIG. 5 shows the rescue catheter placed over the fixed guide wire stent delivery system and through an intimal dissection.  
         [0015]    [0015]FIG. 6 shows the rescue catheter in place with the stent delivery system removed and a conventional guide wire placed through the rescue catheter with its distal end placed beyond the intimal dissection.  
         [0016]    [0016]FIG. 7 shows the guide wire in place and the rescue catheter removed.  
         [0017]    [0017]FIG. 8 is an alternate embodiment of the present invention having a cylindrical distal end and other optional features. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    [0018]FIG. 1 is a side view of a prior art stent delivery system  1  having a fixed guide wire  6  attached to the distal end of a balloon  4  onto which a stent  5  has been mounted. A shaft  2  that extends for most of the length of the stent delivery system  1  is attached at its distal end to the balloon  4  and at its proximal end to a Luer fitting  3 . (This type of stent delivery system is described in detail in U.S. Pat. No. ______ above.) If angiography indicates that there has been an intimal dissection after the stent  5  is placed into an arterial stenosis, the Luer fitting  3  is cut off from the shaft  2  so that a rescue catheter can be advanced over the stent delivery system  1 .  
         [0019]    [0019]FIG. 2 illustrates the delivered stent  5 ′ deployed into an artery with a deflated balloon  4 ′ attached at its distal end to the guide wire  6  and at its proximal end to the shaft  2 . A core wire  9  attached to the fixed guide wire  6  could extend to the proximal end of the stent delivery system  1 .  
         [0020]    [0020]FIG. 3 is a side view of a rescue catheter  10  having a shaft  12  that extends for most of its length, an interior lumen  18  and a distal cone  11  located at a distal portion of the catheter  10 . The shaft  12  has an elongated slit  14  whose distal end  17  is situated between 0.5 and 20 cm from the proximal end of the cone  11 . The cone  11  has a distal opening  13  at its distal end and at least one slit  15  that begins at the distal opening  13  and extends to and possibly beyond the distal end of the cylindrical shaft  12 . The length of the cone  11  should be less than 10 cm and optimally approximately one cm. The length of the cylindrical shaft  12  should be at least 100 cm and optimally longer than 125 cm. The inside diameter of the shaft  12  should be just slightly larger than the maximum outside diameter of the stent delivery system  1 . The inside diameter of the distal opening  13  should optimally be slightly smaller than the shaft  2  in FIG. 1 of the fixed guide wire stent delivery system.  
         [0021]    [0021]FIG. 4 is a longitudinal cross section of a distal portion of the catheter  10  showing the distal cone  11 , the shaft  12 , the distal opening  13 , a slit  15  and the lumen  18 . Although the slit  15  is shown extending into the shaft  12 , it is envisioned that its proximal end could remain within the cone  11  or that it could extend for as much as a centimeter into the shaft  12 . Furthermore, it should be understood that there could be as many as four slits  15  around the circumference of the cone  11  or as few as one.  
         [0022]    [0022]FIGS. 5, 6 and  7  illustrate how the present invention would be used to place a conventional guide wire through an intimal dissection that extends beyond the edge of a stent. FIG. 5 shows the catheter  10  inside an artery into which the stent  5 ′ has been deployed. If there is an intimal dissection  8  extending beyond the edge of the stent  5 ′, it can be detected by the interventional cardiologist using contrast medium. After an intimal dissection is detected, the Luer fitting  3  is cut off from the shaft  2  of the stent delivery system  1 . The interventional cardiologist would then open the cone  11  and place it over the cut off proximal end of the shaft  2  of the stent delivery system  1 .  
         [0023]    The interventional cardiologist would then advance the catheter  10  over the shaft  2  until the proximal end of the shaft  2  could be pulled out of the slit  14 . While holding the proximal end of the shaft  2  in one hand, the interventional cardiologist would, with his other hand, advance the rescue catheter  10  over the stent delivery system  1  until the opening  13  of the cone  11  was advanced over the guide wire  6  and past beyond the intimal dissection  8 . Because of its conical shape, and because the inside diameter of the end hole  13  would be approximately the same as the outside diameter of the guide wire  6 , the distal end of the catheter  10  should readily pass through the dissection  8 . Since it is expected that the diameter of the guide wire  6  would be 0.014 inches, an optimal diameter for the opening  13  of the cone  11  would be approximately 0.014 inches.  
         [0024]    After the rescue catheter  10  is positioned as shown in FIG. 5, the stent delivery system  1  is pulled back out of the catheter  10  and out of the patient&#39;s body. A conventional guide wire  19  is then inserted through the catheter  10  until its distal end lies distal to the intimal dissection  8 . This condition is shown in FIG. 6. The catheter  10  is then removed from the patient&#39;s body and the guide wire  19  remains in place as shown in FIG. 7. Having the slit  14  in the side of the shaft  12  allows a conventional 135 cm length of guide wire  19  to be used. Alternatively, a guide wire  19  that is longer than twice the length of the rescue catheter  10  could be used without utilizing the slit  14  of the catheter  10 .  
         [0025]    [0025]FIG. 8 is an alternative embodiment catheter  50  having a cylindrical distal end with radiopaque marker ring  56 , a shaft  52  and a slit  54  that runs from a point a distance L′ from the distal marker ring  56  to the proximal end  58  of the shaft  52 . The distance L′ is between 0.5 and 20 cm. An access hole  59  at the distal end of the slit  54  facilitates extraction of the proximal end of the fixed guide wire stent delivery system  1  of FIGS. 1 and 2 from the slit when the rescue catheter  50  is inserted into the patient&#39;s body. It is envisioned that a radiopaque marker ring  56  and an access hole  59  could also be used with the tapered end catheter of FIG. 3 where the radiopaque marker ring would be placed just proximal to the proximal end of the distal slit  15 .  
         [0026]    Various other modifications, adaptations, and alternative designs are of course possible in light of the above teachings. Therefore, it should be understood at this time that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.