Abstract:
A method of performing an operation including angioplasty of the internal carotid artery which includes blocking blood flow in the internal carotid artery, performing the angioplasty while the blood flow is blocked in the internal carotid artery, and reversing flow in the internal carotid artery after the angioplasty has been performed to wash material loosened during the angioplasty out of the internal carotid artery. Normal flow in the internal carotid artery is restored after the loosened material is washed out of the internal carotid artery.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of my U.S. Provisional Patent Application Serial Nos. 60/038,040; 60/037,226; 60/037,225; and 60/038,039, all filed Feb. 6, 1997 and all incorporated herein by reference. This application also claims priority of my U.S. Provisional Patent Application also filed on Feb. 6, 1997 with the four above-mentioned provisional patent applications and entitled “ICA ANGIOPLASTY WITH CEREBRAL PROTECTION” and bearing attorney docket number V97004US (16064/4). That application is also incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to internal carotid artery (ICA) angioplasty with cerebral protection. More particularly, the present invention relates to a system for conducting angioplasty while minimizing risk of strokes. 
     2. General Background of the Invention 
     When angioplasties are performed, sometimes plaque gets dislodged and travels into the brain, sometimes causing strokes. 
     The following references are hereby incorporated by reference: 
     Guide catheters these days are introduced generally through the body though a large sheath. There are now some guide catheters which are introduced with a small thin dilator that leads them over a wire into the body, and one ends up with a guide catheter in the body that was gotten in there loaded over the little dilator. These are then in a location not applicable to guide catheter use. For use in a branch vessel, they have to be led by a previously placed selective catheter and/or a guide wire. 
     U.S. Pat. Nos. 3,726,269; 4,033,331; 4,169,464; 4,573,966; 4,925,445; 4,935,017; 5,120,323; 5,163,906; 5,199,951; 5,203,776; 5,215,540; 5,219,355; 5,267,982; 5,290,229; 5,304,131; 5,342,306; 5,348,545; 5,368,566; 5,389,090; 5,458,574; 5,462,529; 5,480,380; 5,484,412; European Patent Specification Publication Nos. 0 339 799 B1 and 0 277 366 A1 and PCT International Application Publication No. WO 96/26758. 
     BRIEF SUMMARY OF THE INVENTION 
     The apparatus of the present invention solves the problems confronted in the art in a simple and straightforward manner. What is provided is a method of performing an operation including angioplasty of the internal carotid artery comprising the following steps: (a) blocking blood flow in the internal carotid artery; (b) performing the angioplasty while the blood flow is blocked in the internal carotid artery; (c) reversing flow in the internal carotid artery after the angioplasty has been performed to wash material loosened during the angioplasty out of the internal carotid artery; and (d) restoring normal flow in the internal carotid artery. 
     Also provided is a guide catheter system which can be inserted into a patient without a sheath, thus allowing the use of large guide catheters without a corresponding larger hole in the vessel wall. 
     The present system allows selective placement of a guide catheter in one step, eliminating the need for a sheath, selective diagnostic catheter, and exchange wire. 
     The entire process of guide catheter introduction is one process, thus much faster. The unit is placed over a standard guide wire through the skin into the vasculature. The lack of need for a separate sheath system saves this step from the introducer. 
     The eventual target vessel for the guide catheter is selected with a catheter/dilator specifically designed for that purpose (the inner “dilator”). This allows optimal design capabilities for the guide catheter due to the fact that it will not have to function as a selecting catheter at the same time. 
     The lack of need for a separate diagnostic catheter to pre-select the intended vessel saves the step of placing a diagnostic catheter into the intended location, placing an exchange wire, pulling the selective catheter, and then placing a guide catheter over this exchange wire. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
     FIG. 1 shows initial placement of the flow control guide catheter; 
     FIG. 2 shows the guide catheter balloon inflated; 
     FIG. 3 shows a soft tipped “wire with a balloon” being advanced through the lesion; 
     FIG. 4 shows the distal balloon inflated; 
     FIG. 5 shows the guide catheter balloon deflated; 
     FIG. 6 show both balloons inflated; 
     FIG. 7 shows the angioplasty being performed; 
     FIG. 8 shows a stent being delivered into the closed system; 
     FIG. 9 shows the stent being deployed; 
     FIG. 10 shows the stent in place; 
     FIG. 11 show the distal balloon deflated; 
     FIG. 12 show the distal balloon re-inflated; 
     FIG. 13 shows the proximal balloon deflated; 
     FIG. 14 shows the proximal balloon inflated; 
     FIG. 15 shows the distal balloon deflated; 
     FIG. 16 shows the guide catheter balloon deflated; 
     FIG. 17 is a schematic view of the vascular tree with the guide catheter system of the preferred embodiment of the apparatus of the present invention present therein; 
     FIG. 18 is a schematic view showing the dilator selecting the origin of a blood vessel; 
     FIG. 19 is a close-up view similar to FIG. 18; 
     FIG. 20 is a view similar to FIG. 19, and showing the guidewire advanced into a distal blood vessel; 
     FIG. 21 shows the dilator/guide catheter unit of the preferred embodiment of the apparatus of the present invention in a position in which the inner dilator has reached its intended location; 
     FIG. 22 shows the dilator/guide catheter unit of the preferred embodiment of the apparatus of the present invention where the guide catheter has been advanced over the inner dilator catheter to the intended location; and 
     FIG. 23 is a view similar to FIG. 22, after the inner dilator and guidewire have been removed from the guide catheter. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1 initial placement of the flow control guide catheter  111  has been made, but the balloon  118  has not been inflated; antegrade flow is still present in the common carotid artery  61  and internal and external carotid arteries  71 ,  72 . 
     In FIG. 2, inflation of the guide catheter balloon  118  stops flow in the common carotid artery  61  and reverses flow in the internal carotid artery  71 . The high pressure intracranial vascular system will supply the low pressure sump of the external carotid artery  72 . 
     In FIG. 3, while flow reversal is occurring, a soft tipped “wire with a balloon”  80  is advanced safely through the lesion  40 ; any material displaced during passage will flow in a retrograde course out the external carotid artery  72 . 
     In FIG. 4, the distal balloon  81  is inflated, stopping all flow in the internal carotid artery  71 . 
     In FIG. 5, the guide catheter balloon  118  is deflated, washing out the stagnant blood and debris in the region of the stenosis  40 . 
     In FIG. 6, both balloons  81 ,  118  are inflated and the angioplasty catheter  90  is delivered safely to its intended location. 
     In FIG. 7, the angioplasty is performed while flow is arrested in the common carotid  61  and internal carotid  71  arteries. 
     In FIG. 8, after initial angioplasty, a stent  50  is delivered into the closed system, again with both the distal and proximal flow occluded. 
     In FIG. 9, the stent  50  is safely deployed under flow arrest. 
     In FIG. 10, the angioplasty catheter  90  is withdrawn, leaving the stent  50  in place with flow arrested in the carotid arteries  61 ,  71 ,  72 . 
     In FIG. 11, the distal balloon  81  is deflated, allowing reversal of flow again in the internal carotid artery  71 . This allows any retained material to be washed into the external carotid artery  72  again. 
     In FIG. 12, the distal balloon  81  is re-inflated, again stopping flow in the internal carotid artery  71 . 
     In FIG. 13, the proximal balloon  118  is deflated. This allows high pressure antegrade flow into the external carotid artery  72  and allows contrast injection through the inner lumen of the guide catheter  111 . Evaluation of the result of the angioplasty/stent is now possible. Any retained material is now forcefully washed out of the system into the external carotid artery  72 . 
     In FIG. 14, the proximal balloon  118  is again inflated. 
     In FIG. 15, the distal balloon  81  is deflated. While flow is again reversed in the internal carotid artery  71 , the distal wire/balloon  80  is safely withdrawn, again with no chance of dislodging any material into the intracranial flow. 
     In FIG. 16, once the inner wire/balloon  80  has been withdrawn, the guide catheter balloon  118  is deflated, allowing final contrast injection through the guide catheter lumen to evaluate the results. 
     This is also the technique of choice for internal carotid artery stenting due to its excellent cerebral protection. 
     1. Select the common carotid artery  61  using a selective diagnostic cerebral catheter; evaluate the path available to the angioplasty site. 
     2. Exchange the diagnostic catheter for a flow control guide catheter utilizing a safe “neuro” exchange wire. (Instead of the first two steps listed above, one could instead use the flow control guide catheter  111  of the present invention which is a modified version of the guide catheter disclosed in the attached provisional patent application entitled “Guide Catheter System”, which modified version is discussed below). 
     3. Inflate the balloon  118  on the flow control catheter  111 , occluding flow in the common carotid artery  61  and resulting in reversal of flow in the internal carotid artery  71  or cessation of flow (at the very least). 
     4. Load a micro-occlusion balloon catheter  80  containing a microwire through the selected angioplasty balloon catheter  90 . (This will necessitate the placement of a microballoon on a microcatheter after loading, or the use of a proprietary device, currently in development.) Carefully navigate the micro-occlusion balloon  81  past the stenosis  40  with the angioplasty balloon  91  remaining proximal within the guide catheter lumen. The occluded common carotid artery  61  thus protects this initial dangerous crossing. 
     5. Before inflating the distal balloon  81 , aspirate through the guide catheter  111  to remove any debris dislodged during the initial crossing of the plaque  40 ; any remainder will flow in a retrograde direction into the external carotid artery  72 . 
     6. Inflate the distal micro-occlusion balloon  81 , stopping all flow in the internal carotid artery  71 . 
     7. Deflate the guide catheter occlusion balloon  118 ; this now allows the previously stagnant blood in the common carotid artery  61  to wash out into the external carotid artery  72  and refreshes this territory. It also further washes out the potentially disturbed stenotic region, with debris again going into the external carotid artery  72 . 
     8. Reinflate the guide catheter occlusion balloon  118 , ceasing flow in the common carotid artery  61 . 
     9. Advance the angioplasty catheter  90  over the wire/micro-occlusion balloon  80  into place and perform the angioplasty (and stent placement, if applicable). 
     10. Deflate the angioplasty balloon  91  and withdraw this catheter  90 . 
     11. Slowly infuse contrast through the guide catheter  111  to visualize the angioplasty site. 
     12. Repeat if necessary (and place stent if necessary). 
     13. Open the external lumen of the guide catheter  111  to the air. 
     14. Deflate the distal occlusion balloon  81  and let backbleeding occur for a few seconds, both into the external carotid artery  72  and out the guide catheter  111 . 
     15. Close the external drainage of the guide catheter  111 ; let the retrograde flow from the internal carotid artery  71  continue into the external carotid artery  72 . Perfuse with ReoPro, etc., as indicated. 
     16. Perform repeat angiogram to evaluate the status of the angioplasty site by injecting through the guide catheter lumen, slowly. 
     17. Remove all indwelling catheters/balloons except for the guide catheter  111 . 
     18. Deflate the guide catheter balloon  118  and perform final angioplasty site evaluation. 
     19. Perform final evaluation of intracranial cerebral vasculature. 
     The preferred guide catheter system for getting the balloon catheter  111  to its intended location is the guide catheter system shown in FIGS. 17-23, but modified to include a balloon  118  on the guide catheter  111  disclosed herein. Thus, one could use the system shown in FIGS. 17-23, replacing the catheter  11  shown in FIGS. 17-23 with balloon catheter  111 , which is the same as catheter  11  except that catheter  111  also includes a balloon  118  and means for inflating and deflating balloon  118 . 
     PRODUCT: 
     The guide catheter design of the present invention incorporates design characteristics of a guide catheter with a method of introduction of the guide catheter into the vascular system and then into the target vessel all in one step. 
     PRODUCT DESCRIPTION: 
     TWO COMPONENTS: 
     1. A custom designed guide catheter  11 , with a non-tapering inner and outer lumen size but with varying stiffness in the shaft tapering from a very stiff proximal shaft  13  to a very soft, atraumatic tip  12 . Outer diameter of the guide will be non-tapering and can be from 5 fr. to 10 fr. 
     2. A custom made inner “dilator”  14  snugly hugging an 0.035 inch standard guidewire  21  and gradually expanding to fill the inner lumen of the guide catheter  11 . This inner dilator  14  will be substantially longer than the guide catheter  11  and have a preshaped curve  15  to allow selection of vessels similar to the function of a standard diagnostic catheter. This dilator  14  will be used to introduce the guide catheter  11  through the skin. The inner dilator catheter  14  will extend approximately 10-30 cm past the tip  12  of the guide catheter  11  and be used to select the intended target vessel  61  of the guide catheter  11 , just as a standard selecting diagnostic catheter would be used. 
     DESCRIPTION OF USE: 
     The inner dilator  14  will extend from 10-30 cm past the guide catheter tip  12 . This will be introduced over a standard guide wire  21  placed into the vascular tree  60  utilizing standard Seldinger technique. Once the wire  21  is in place, the dilator/guide catheter unit  10  will be slid over this wire  21  into place in the vascular tree  60  (FIG.  17 ). The intrinsic curve  15  of the inner dilator  14  will then be used to select the origin of a blood vessel  61  (FIGS.  18  and  19 ). A standard guidewire  21  will be placed through this into the distal blood vessel  61  (FIG.  20 ). The dilator/guide catheter unit  10  will be slid over this guidewire  21  until the inner dilator  14  has reached its intended location  62  (FIG.  21 ). The wire  21  and inner dilator  14  will be held in place and the guide catheter  11  advanced over this until it has reached its intended location  62  (FIG.  22 ). The inner dilator  14  and wire  21  will be pulled, leaving the guide catheter  11  in its intended location  62  (FIG.  23 ). 
     ADVANTAGES OVER STANDARD GUIDE CATHETER DESIGN: 
     1. The guide catheter can be introduced without the use of a large sheath, thus allowing the use of large guide catheters without a corresponding larger hole in the vessel wall. 
     2. The entire process of guide catheter introduction will be one process, thus much faster. The unit will be placed over a standard guide wire through the skin into the vasculature. The lack of need for a separate sheath system saves this step from the introducer. 
     3. The eventual target vessel for the guide catheter will be selected with a catheter/dilator specifically designed for that purpose (the inner “dilator”). This will allow optimal design capabilities for the guide catheter due to the fact that it will not have to function as a selecting catheter at the same time. 
     4. The lack of need for a separate diagnostic catheter to pre-select the intended vessel saves the step of placing a diagnostic catheter into the intended location, placing an exchange wire, pulling the selecting catheter, and then placing a guide catheter over this exchange wire. 
     Guide catheters these days are introduced generally through the body though a large sheath. And there are now some guide catheters which are introduced with a small thin dilator that leads them over a wire into the body, and one ends up with a guide catheter in the body that was gotten in there loaded over this little dilator. The present invention is a new system and technique for getting a guide catheter to the intended location which is described on the attached drawings (FIGS.  17 - 23 ). The tip of the dilator has been extended a considerable distance past the guide catheter itself so that now the tip of this dilator acts not only as a small introducing agent to follow the wire to get the guide catheter into the body, but also has the purpose of being able to select the vessel. So once one gets it into the vascular tree, one can fish downstream, select the vessel that is intended for the final location of the guide catheter. Once one has selected the vessel, then one uses a guide wire through it, just like with a standard diagnostic catheter. One places a wire downstream into the intended vessel, fishes the entire dilator/guide catheter system downstream into this vessel, and then once the dilator gets downstream, one pushes the entire guide catheter off it until it gets to its intended location down to where one wants to leave it. At that point, one pulls the wire and dilator back, leaving the guide catheter in place. Therefore, in basically one giant procedure, one introduces all of the catheter system through the skin, into the body, and up the vessel, into the final location. The advantage of getting the catheter into the selected vessel into its final location in one step is that one does not have to do any exchanges or use various materials being put into and out of the body and steps along the way to get the guide catheter to the place where one intends it to be. 
     This system allows one to do away with the sheath. It allows one to do away with a normal selecting diagnostic catheter to select the vessel. It allows one to do away with an exchange wire, or putting the exchange wire up into the vessel and then pulling the diagnostic catheter out and then putting the guide catheter in over the exchange wire and finally getting into position that way. So instead of having these multiple steps in the procedure, one basically have this one continuous step to get the guide catheter into the final location. 
     Typical dimensions for a guide catheter  11  of the present invention are as follows: length: 40-130 cm (90-100 cm, for example); outer diameter: 1.5-5 mm, preferably 5-12 fr. (6 french, for example); inner diameter: 4 fr.-10 fr. 
     Typical dimensions for a dilator catheter  14  of the present invention are as follows: length: 50-175 cm (about 20 cm longer than the guide catheter, for example); outer diameter: (sized to match the inner diameter of the guide catheter); inner diameter: sized to fit over a guide wire (0.040 inches, for example). 
     The curve  15  is chosen such that it aids in selecting the origin of the intended blood vessel. The radius of curvature of the curve  15  can be as in the Cook diagnostic cerebral catheters. 
       10  Parts list 
       10  guide catheter system 
       11  guide catheter 
       12  soft, atraumatic tip of guide catheter  11  (made of, for example, nylon or polyethylene) 
       13  very stiff proximal shaft of guide catheter  11  (made of, for example, braided, multilayer construction) 
       14  inner dilator catheter (made of, for example, nylon or polyethylene) 
       15  pre-shaped curve of inner dilator catheter  14   
       21  guidewire (Terumo stiff-shaft angle-tip glide wire commercially available from Terumo in Japan and distributed by Boston Scientific) 
       22  curved tip of guidewire  21   
       40  stenosis 
       50  stent (made of stainless steel and could be, e.g., a stent commercially available from Palmaz) 
       60  vascular tree 
       61  selected vessel (common carotid artery) 
       62  intended location of tip  112  of catheter  111  (or tip  12  of catheter  11 ) 
       71  internal carotid artery 
       72  external carotid artery 
       80  wire with balloon (e.g., a wire with balloon commercially available from Johnson &amp; Johnson as part no. P104) 
       81  balloon of wire  80   
       90  angioplasty catheter (e.g., a Diamond™ brand angioplasty catheter commercially available from Boston Scientific having a balloon which is 6 mm in diameter by 20 mm long) 
       91  balloon of angioplasty catheter 
       110  guide catheter system 
       111  guide catheter (e.g., a catheter commercially available as FasGuide made by Target Therapeutic) 
       112  soft, atraumatic tip of guide catheter  111   
       113  very stiff proximal shaft of guide catheter  111   
     Enclosed is an appendix with more information about the present invention. 
     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise. 
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.