Abstract:
An angioplasty procedure wherein a balloon dilatation catheter is movably positioned within an anchoring catheter and which in turn is located within a guiding catheter or wherein a balloon dilatation catheter is movably positioned within a guiding catheter and the anchoring catheter in turn is positioned on the external surface of the guiding catheter, or wherein a balloon dilatation catheter is movably positioned within a catheter which serves both as a guiding catheter and anchoring catheter. Additionally, valve elements are attached to the guiding and anchoring catheters to provide points of securement between the catheters and the balloon dilatation catheter and to prevent the backflow of blood through the catheter assembly. Actuation of the valve elements allows a doctor to control the movement of the catheters.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     Cardiac catheterization and angioplasty are common medical procedures. The coronary arteries are vessels which supply the heart muscle with blood and are located on the outside surface of the heart. In order to visually examine the coronary arteries, a contrast agent has to be injected into the vessels before x-ray pictures can be taken of them. This is accomplished through a procedure called cardiac catheterization. This contrast agent is delivered through a catheter, which is a small hollow tube. This catheter is advanced to the heart under x-ray guidance, usually being inserted at the level of the groin into the femoral artery. This is accomplished through a needle which is first advanced into the femoral artery and subsequently the catheter is passed through the needle into the blood vessel or femoral artery. The femoral artery in turn is a tributary of the great vessel originating in the heart and therefore the catheter can be passed in a retrograde fashion under x-ray guidance very easily back to the origin of the coronary arteries.  
         [0002]     Once the catheter is positioned at the origin of the coronary arteries, a dye syringe is placed on the end of the catheter remaining outside the patient and injections are performed with simultaneous x-ray pictures being taken.  
         [0003]     An angioplasty procedure is similar in technique but more invasive, by the fact that a smaller catheter with a deflated balloon on its tip is advanced through the catheter which is positioned at the origin of the coronary artery and advanced down into the coronary artery to the site of where the vessel is narrowed. The balloon dilatation catheter is not advanced down the coronary artery by itself; however, first, a very small guide wire is advanced down the coronary artery, across the narrowed segment and then advanced further down into the coronary artery, beyond the narrowed segment. The balloon dilatation catheter is then advanced over the guide wire to the site of the narrowing. The guide wire allows the balloon dilatation catheter to track over it, thereby facilitating advancement of the balloon dilatation catheter down the vessel and thus preventing damage to the vessel wall. Once the balloon is positioned at the site of the narrowing in the vessel, the balloon is inflated by means of a hand held balloon inflation device. The balloon is inflated for generally 30 to 90 seconds and then deflated and withdrawn. This compresses the fatty-like material which is responsible for narrowing the coronary artery and opens the vessel, allowing for proper blood flow to the heart muscle.  
         [0004]     At times it is difficult to advance the balloon dilatation catheter to the site of the narrowing, as these vessels are not always straight and often times bends in the vessel have to be negotiated before reaching the point of narrowing. Frequently, the balloon dilatation catheter cannot be easily advanced and the guiding catheter which is housing the balloon dilatation catheter and the guide wire comes loose from its position at the origin of the coronary artery and does not provide enough structural support or backup to allow advancement of the balloon dilatation catheter to the narrowed site.  
         [0005]     Improvements in this field have been made such as for example, the angioplasty method and means for performing angioplasty seen in U.S. Pat. No. 5,484,412. Specifically, in this patent a method and means is provided using a plurality of different catheters that are all interconnected using a plurality of balloons to provide more accurate handling and control to improve angioplasty procedures. Despite this improved means and method additional improvements are desired. Specifically, a need exists for the use of non inflatable equipment that accomplishes similar results.  
         [0006]     Thus, the principal object of the present invention is to provide an improved method and means for performing an angioplasty that provides structural support to the guiding catheter.  
         [0007]     Another object of the invention is to provide catheter designs having the capability of proximal embolic protection.  
         [0008]     These and other objects, features, or advantages of the present will become apparent from the specification and claims.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     This invention comprises an angioplasty procedure wherein the balloon dilatation catheter is movably positioned within an anchoring catheter which in turn is located within a guiding catheter. Optional internal balloons in the anchoring catheter can be inflated to secure the balloon dilatation catheter to the inside of the anchoring catheter. External balloons on the anchoring catheter can be inflated to anchor it to the inside of the guiding catheter and to the inside of the coronary artery. The external fixation balloons can be selectively inflated and deflated from the internal fixation balloons.  
         [0010]     Additionally attached to the guiding catheter is a valve element that comprises a valve stem with threads and a valve opening therein such that the balloon dilation catheter can be passed through the valve opening such that when the valve is turned the balloon dilatation catheter is secured within the opening to secure the balloon dilatation catheter to the guide catheter. Alternatively, an anchoring catheter may be used with a similar valve element such that the balloon dilatation catheter can be secured to the anchoring catheter in a similar manner. Additionally the anchoring catheter or the guide catheter can be made of an inner and outer sheath that is attached distally to expandable material such that as the outer sheath and inner sheath slide over each other the material radially retracts or expands accordingly.  
         [0011]     The method of this invention inserts a conventional guiding catheter into the origin of the coronary artery, (coronary ostium). A conventional guide wire and balloon dilatation catheter are then inserted through the anchoring catheter which in turn is inserted through the guiding catheter. Once the anchoring catheter is properly positioned in the proximal portion of the coronary artery and fixed in position with the use of external fixation balloon(s), the anchoring catheter is then secured to the guiding catheter using a valve element such that the dilatation catheter can be slid though the anchoring catheter and guide catheter along the guide wire until the dilatation balloon attached to the dilatation catheter is adjacent a plaque area of the blood vessel. At this time the dilatation balloon may be inflated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a schematic view of a human heart with the apparatus of this invention inserted into a coronary artery;  
         [0013]      FIG. 2  is an enlarged scale sectional view of a catheter assembly;  
         [0014]      FIG. 3  is an enlarged scale sectional view of a catheter assembly;  
         [0015]      FIG. 4  is an enlarged scale sectional view of a catheter assembly;  
         [0016]      FIG. 5  is an enlarged scale sectional view of a catheter assembly;  
         [0017]      FIG. 6  is an enlarged scale sectional view of a catheter assembly;  
         [0018]      FIG. 7  is an enlarged scale sectional view of a catheter assembly.  
         [0019]      FIG. 8  is a sectional view of a valve element; and  
         [0020]      FIG. 9  is a sectional view of a valve element. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]      FIG. 1  shows a schematic view of a heart muscle  10  connected to the primary blood supply vessel  12  (aorta). A coronary artery  14  is also depicted in  FIG. 1 . The numeral  14 A in  FIG. 1  shows the plaque or obstruction in the coronary artery  14 .  
         [0022]      FIG. 1  also shows a first embodiment of a catheter system similar to that shown in U.S. Pat. No. 5,484,412 to Pierpont. The &#39;412 reference is incorporated herein. In general the catheter system includes a conventional guide wire  16  over which a balloon dilatation catheter  18  is slidably mounted. Catheter  18  has an inflatable balloon  18 A on the distal end thereof. Catheter  18  has its internal diameter divided by a membrane to create a balloon inflation passageway and a guide wire passageway  20  as is taught in the &#39;412 reference.  
         [0023]     The catheter system also includes an anchoring catheter  22  having a side wall  24  with an internal balloon  30  to secure the anchoring catheter to the balloon dilatation catheter  18 . The side wall  24  also has a side port  31  for connection to a manifold that allows pressure monitoring, injection of saline to allow flushing and aspiration and injection of contrast to visualize the vessel. Extending from the outer wall  24  are first and second concentric external balloons  36  and  38  to provide a means to secure the anchoring catheter to a guide catheter  41  and blood vessel wall.  
         [0024]      FIGS. 2-7  show several catheter systems that represent improvements over the catheter system shown in  FIG. 1 . Specifically  FIGS. 2-7  show several different embodiments of how the guide catheter  41  and anchor catheter  22  may be secured and connected using inner and outer sheaths  24 A and  24 B, a valve element  44  ( FIGS. 8 and 9 ) or a combination of both.  
         [0025]     As best shown in  FIGS. 8 and 9  the valve element  44  has a threaded stem  46  that threadably engages a threaded receptacle  47  that surrounds and is on the proximal end of the guide catheter  41  or anchor catheter  22 . The stem  46  has a valve opening  48  therein such that as the stem  46  is turned in a clockwise position on the threaded receptacle  47  the opening prevents fluid flow through the body wherein if turned in a counter clockwise position the valve opening  48  opens to allow fluid communication through the valve element  44 . In one embodiment this valve element  44  is a thouey-borst® valve that is known in the angioplasty art. Typically, the valve element  44  is used to prevent the back flow of blood through the fluid passageway in which the valve element  44  is inserted.  
         [0026]     In the embodiments of  FIGS. 2-7  the valve element is additionally used to function as a securing device. Specifically, when the valve element  44  is attached to the anchor catheter  22  the balloon dilatation catheter  18  is able to be disposed through the valve opening  48  such that when the stem  46  is turned in a clockwise position the valve element  44  closes on the balloon dilatation catheter  18  and thus secures the balloon dilatation catheter  18  to the anchoring catheter  22 . In such an arrangement not only does the valve element  44  prevent back flow of blood it additionally acts as a securing device to help with the control of catheters used during an angioplasty.  
         [0027]      FIG. 2  shows an embodiment wherein the anchoring balloons  36  and  38  are eliminated. Specifically, the side outer wall  24  of anchoring catheter  22  has inner and outer sheaths  24 A and  24 B that slide over each other. Expandable material is disposed between the inner and outer sheaths  24 A and  24 B and radially retracts and expands as the outer and inner sheaths slide back and forth over each other. By radially expanding the expandable material the material can engage the guide catheter  41  or blood vessel to secure the anchoring catheter  22  to each. In this manner the external balloons  36  and  38  may be eliminated. Though in another embodiment the balloons  36  and  38  could remain to provide an additional securing means.  
         [0028]      FIG. 3  is a variation of  FIG. 2  in that the anchoring catheter  22  comprises inner sheath  24 A and outer sheath  24 B wherein the inner sheath extends past the outer sheath at the proximal end and has a section of expandable material  52  at the distal end. The section of expandable material  52  acts similarly to inflatable balloon  38  wherein inflated the external balloon  38  temporarily occludes or blocks blood flow through the coronary artery  14 . Unless the selected embodiment of anchoring catheter  22  includes optional perfusion ports either located proximal or proximal and distal to the external balloon  38 . Similarly, the section of expandable material  52  occludes or blocks blood flow through the coronary artery  14  unless the selected embodiment of anchoring catheter  22  includes optional perfusion ports located proximal or proximal and distal to the section of expandable material  52  or is established through the section of expandable material  52  being made porous.  
         [0029]     Temporary occlusion at a vessel location proximal to targeted obstruction  14 A is useful to prevent distal embolization by plaque debris that may be dislodged during an angioplasty and subsequently entrained in the blood flow. Proximal occlusion to prevent distal embolization typically includes the aspiration of potentially contaminated blood following dilation, but prior to either deflating balloon  38  or contracting the section of expandable material  52  which allows blood flow to resume. Aspiration can be performed through an interior lumen of anchoring catheter  22  by drawing a partial vacuum at the proximal end thereof, using for example, a syringe. If aspiration is difficult, a flush solution can be injected through the interior lumen of the anchoring catheter  22  before aspirating.  
         [0030]     Further, in the embodiment of  FIG. 3 a  valve element  44  is placed on the proximal end of the inner sheath  24 A, a second valve element  50  is placed on the proximal end of the outer sheath  24 B and a third valve element  54  is placed on the proximal end of the guiding catheter. Thus, when the first valve element  44  is turned in a clockwise position and the balloon dilation catheter  18  is disposed therethrough, the balloon dilation catheter  18  is secured to the inner sheath  24 A. Similarly, when the second valve element  50  is rotated clockwise the outer sheath  24 B is secured to the inner sheath  24 A just as when the third valve element  54  is rotated in a clockwise position the outer sheath  24 B is secured to the guide catheter  41 .  
         [0031]      FIG. 4  shows yet another alternative embodiment wherein the anchoring catheter  22  acts as a sleeve that fits over the guiding catheter  41 . In this embodiment the guiding catheter  41  has a first valve element  44  through which the balloon dilation catheter  18  and guide wire  16  are passed. Additionally a second valve element  50  is fitted on the proximal end of the anchoring catheter  22  through which the guiding catheter  41  is passed while sliding the anchoring catheter  22  over the guiding catheter beginning at the distal tip of the guiding catheter  41  and working backwards. The second valve element  50  when tightened on the guiding catheter  41  secures the anchoring catheter  22  to the guiding catheter  41 . Again, the use of multiple valve elements allows further control of the catheter assembly.  
         [0032]     In this embodiment a funnel insert (not shown) may optionally be used to facilitate the placement of anchoring catheter  22  on the distal end of the guiding catheter  41  as a sleeve element. Specifically the funnel insert spreads open the anchoring catheter  22  to align the anchoring catheter  22  with the guiding catheter  41 . Once aligned the funnel insert is withdrawn and the anchoring catheter  22  is placed over the guiding catheter  41 . The funnel insert can similarly be used with the dual sheath design depicted in  FIG. 5 .  
         [0033]     In the embodiment shown in  FIG. 5  the anchoring catheter is composed of inner and outer sheaths  24 A and  24 B that act like a sleeve placed over the guiding catheter  41  as is shown in  FIG. 4 . The guiding catheter  41  additionally has a first valve element  44  through which the balloon dilation catheter  18  and guide wire  16  would be placed into the guiding catheter  41 . In this embodiment second and third valve elements  50 ,  54  are connected to the proximal ends of both the inner and outer sheaths  24 A and  24 B. In this way the second valve element  50  on the inner sheath  24 A would fix its position relative to the guiding catheter  41  and would prevent blood from dripping back as well. The third valve element  54  on the outer sheath  24 B would fix its position relative to the inner sheath and would prevent blood from dripping back through the outer sheath  24 B.  
         [0034]      FIG. 6  shows another alternative design wherein the anchoring catheter  22  and guiding catheter  41  are combined into a single catheter that is considered guide catheter  41 . Thus, a valve element  44  is on the proximal end of the guiding catheter  41  to secure the balloon dilation catheter  18  and wire  16  therein. Additionally, the external balloon  38 , when inflated within the coronary artery  14  anchors the guiding catheter  41  to the coronary artery  14 . In this embodiment wherein sheaths are employed a section of expandable material  52  functions similar to the external balloon  38  of  FIG. 6  as with other such embodiments.  
         [0035]     In a final alternative embodiment as in the embodiment shown in  FIG. 6 , in  FIG. 7  the anchoring and guiding catheters are combined to provide a single guiding catheter  41 . In this embodiment the guiding catheter  41  has inner and outer sheaths  41 A and  41 B wherein a first valve element  44  is at the proximal end of the inner sheath  41 A whereas a second valve element  50  is at the proximal end of the outer sheath  41 B. Thus, the valve element  44  on the inner sheath  41 A serves to prevent backflow of blood and additionally allows entry of the balloon dilatation catheter  18  and guide wire  16 . Meanwhile, the second valve element  50  on the outer sheath  41 B prevents backflow of blood and also secures the outer sheath  41 B onto the inner sheath  41 A locking the sheaths  41 A and  41 B into place.  
         [0036]     The  FIGS. 2-7  each show the use of side port  31  used in association with first and second valve elements  44 ,  50 . Similarly, port  31  could be used in association with valve element  54 . Additionally, while only a single side port is shown in each figure, a plurality of side ports could be used such that each valve element  44 ,  50  and  54  could have a side port  31  without falling outside the scope of this disclosure.  
         [0037]     In operation, the guiding catheter  41  is inserted into the groin of the patient in the manner described above and positioned at the origin of the coronary artery  14 . The balloon dilatation catheter  18  is inserted over guide wire  16 , and both the guide wire  16  and balloon dilatation catheter  18  are then inserted within anchoring catheter  22 . The assembled guide wire  16 , balloon dilatation catheter  18  and anchoring catheter  22  are moved as a unit into guiding catheter  41 . At this point in time, the external balloons  36  and  38  of anchoring catheter  22  are still deflated. The above described assembled components are extended through the guiding catheter until the guide wire  16  and the distal end of the anchoring catheter  22  extend distally beyond the distal end of the guiding catheter. At that point in time, the internal balloons  30  are deflated in the manner described by valve  42  and the external balloons  36  and  38  are inflated. The external balloon  38  engages the inner wall of coronary artery  14 , while the external balloon  36  engages the interior of the guiding catheter  41 . In other embodiments external balloons  36  or  38  are used. In either embodiment the guiding catheter  41  is secured to the coronary artery  14 .  
         [0038]     Additionally, when using valve elements  44 ,  50  or  54  the method includes securing either the catheters themselves together or the sheaths of the catheters together. Specifically, in one embodiment a valve element  44  can secure an anchoring catheter  22  to a guiding catheter  41  whereas in another embodiment the inner and outer sheaths of the anchor catheter  22  or inner and outer sheaths of a guiding catheter  41  are secured together. Similarly, the balloon dilation catheter  18  and wire  16  can be secured to either an anchoring catheter  22  or a guiding catheter  41  using a valve element  44  depending on the needed application. By using the plurality of valve elements backflow of blood is prevented, and a plurality of arrangements allowing for better control of all catheters is presented.  
         [0039]     Additional configurations of catheters are proposed. Various advantages are afforded by these different designs such as the anchoring catheter which slips over the guiding catheter allowing for universal adaptability to pre-existing guiding catheters, and catheters with distally positioned soft expandable material which may be softer and possibly more tenacious to the vessel wall than balloons, and the single catheter design which is advantageous in its simplicity with either a distal balloon or the use of distally positioned soft expandable material. Use of perfusion ports allows perfusion during the process of anchoring the guiding catheter to the coronary ostium. Lack of perfusion ports allows the anchoring catheter to be utilized for proximal embolic protection. Thus, at the very least all of the stated objectives have been met.  
         [0040]     Although some descriptions of the invention referred to angioplasty systems, dilatation balloons, balloon dilatation catheters and treatment of coronary arteries, it should be understood that such elements are merely exemplary and the invention can be used in conjunction with a variety of treatment catheters and in different vessels of the human body. Treatment catheters can include treatment elements such as, for example, angioplasty balloons, stents, and stent delivery components and radiation therapy apparatuses. As well, it should be understood that the invention can be utilized in separate vein grafts and arterial bypass grafts. Additionally, the use of known catheter configurations is contemplated within the scope of this disclosure. For example, a side entry port as contemplated by U.S. Pat. Nos. 5,489,271 and 5,554,118 for insertion of catheters is contemplated without falling outside the scope of this disclosure.  
         [0041]     It will be appreciated by those skilled in the art that other various modifications could be made to the device without the parting from the spirit and scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby.