Abstract:
A medical catheter comprising a guide wire shaft having an inner diameter defining an inner lumen and an outer diameter, the guide wire shaft having a proximal portion and a distal portion, an inflation lumen tube defining an inflation lumen, the inflation lumen tube having a proximal end and a distal end, the guide wire shaft extending distal to the inflation lumen tube, an inflatable balloon having a proximal end and a distal end, the balloon distal end being sealingly affixed to the distal end of the inner lumen tube, the balloon proximal end being sealingly affixed to the distal end of the inflation lumen tube, the balloon being in fluid communication with the inflation lumen and at least one marker band being imbedded in the distal portion of the guide wire shaft, the marker band being positioned between the proximal end and the distal end of the inflatable balloon such that the marker band can be viewed under fluoroscopy.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an angioplasty catheter and more particularly to an imbedded marker band creating a flexible guide wire shaft. 
     BACKGROUND OF THE INVENTION 
     Percutaneous transluminal coronary angioplasty (PTCA) is used to increase the lumen diameter of a coronary artery partially or totally obstructed by a build-up of cholesterol fats or atherosclerotic plaque. Typically a first guide wire of about 0.038 inches in diameter is steered through the vascular system to the site of therapy. A guiding catheter, for example, can then be advanced over the first guide wire to a point just proximal of the stenosis. The first guide wire is then removed. A balloon catheter on a smaller 0.014 inch diameter second guide wire is advanced within the guiding catheter to a point just proximal of the stenosis. The second guide wire is advanced into the stenosis, followed by the balloon on the distal end of the catheter. The balloon is inflated causing the site of the stenosis to widen. The dilatation of the occlusion, however, can form flaps, fissures and dissections which threaten reclosure of the dilated vessel or even perforations in the vessel wall. 
     Although the dimensions in the above example are suited to the coronary arteries, any body lumen can be treated by percutaneous transluminal angioplasty (PTA), including the vas deferens, ducts of the gallbladder, prostate gland, trachea, bronchus and liver. The body lumens range in diameter from small coronary vessels of 3 mm or less to 28 mm in the aortic vessel. The invention applies to acute and chronic closure or reclosure of body lumens. 
     It is advantageous for a catheter to have visible marker bands on the catheter shaft that can be viewed using a fluoroscope machine to position the catheter in relation to the lesions. It is also advantageous for a catheter shaft to have a smooth outer surface with minimal bumps from the marker bands. What is needed is marker bands which can be visible using a fluoroscope and also which do not create a significant increase in diameter so that the catheter can slide easily through the lesion. 
     U.S. Pat. Nos. 5,489,277 and 5,256,158 to Tolkoff et al. for “Device Having a Radiopaque Marker for Endoscopic Accessories and Method of Making Same” discloses a radiopaque ring that is inserted into an expanded section of tubing, followed by the relaxation of the tube to its original dimensions. U.S. Pat. No. 5,485,667 to Kleshinski for “Method for Attaching a Marker to a Medical Instrument” discloses a marker made of tubular radiopaque shape memory material that is deformed and then slid over or into the tubing and then heated so that the shape memory material returns to its original shape and attaches to the tubing. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a marker band that is imbedded into the guide wire shaft providing a smooth surface. 
     The present invention is accomplished by providing an apparatus and method of manufacture for a medical catheter, comprising a guide wire shaft having an inner diameter defining an inner lumen and an outer diameter, the guide wire shaft having a proximal portion and a distal portion, an inflation lumen tube defining an inflation lumen, the inflation lumen tube having a proximal end and a distal end, the guide wire shaft extending distal to the inflation lumen tube, an inflatable balloon having a proximal end and a distal end, the balloon distal end being sealingly affixed to the distal end of the inner lumen tube, the balloon proximal end being sealingly affixed to the distal end of the inflation lumen tube, the balloon being in fluid communication with the inflation lumen and at least one marker band being imbedded in the distal portion of the guide wire shaft, the marker band being positioned between the proximal end and the distal end of the inflatable balloon such that the marker band can be viewed under fluoroscopy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the catheter of the invention; 
     FIG. 2 is a cross-section of the distal end of the catheter of FIG. 1; and 
     FIG. 3 is a cross-section of the distal guide wire shaft of the catheter of FIG.  2 . 
     FIG. 4 is an alternate embodiment of FIG. 1 
     FIG. 5 is similar to FIG. 2 
     FIG. 6 is similar to FIG.  3   
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 &amp; 2, Applicant&#39;s catheter  10  is comprised of a balloon  15 , shaft  20 , and manifold  25 . Marker bands  30  are located inside of the balloon  15 . The marker bands  30  are required to position the balloon  15  using fluoroscopy during an angioplasty procedure. The intent behind the invention is to minimize the increase in diameter over the marker band  30 , while enabling it to be viewed using standard fluoroscope equipment. Fluoroscope evaluations conducted using platinum/iridium marker bands  30  indicate that a wall thickness of 0.0010″ is not sufficient to ensure adequate visibility, while a wall thickness of 0.0018″ will enable good visibility. Traditionally, marker bands are placed on the outside of the guidewire lumen using adhesive (cyanoacrylate). This requires the inner diameter of the marker band to be large enough to enable it to be positioned onto the guide wire shaft with a sufficient gap to enable the adhesive to wick between the guide wire shaft and marker band for bonding purposes. Imbedding the marker bands  30  using the present invention creates an increase in diameter of approximately 0.005″ when compared to the diameter of the guide wire shaft  35 . Typical dimensions for this configuration are 0.023″ over the guide wire shaft  35  and 0.028″ over the marker band  30 . A conventional over-the-wire design consists of a guide wire shaft  35  which defines a guide wire lumen  40  running the length of the catheter  10  inside of the shaft  20 . 
     Imbedding the marker band  30  using the method described in this patent allows the wall thickness to be maintained to enable sufficient visibility without resulting in a significant increase in outer diameter. Samples prepared using platinum/iridium marker bands  30  with the following dimensions: 0.01675″ inner diameter, 0.0018″ wall, 0.051″ length resulted in an increase in diameter over the marker band  30  of 0.002″ when compared to the diameter of the guide wire shaft  35 . Typical dimensions for this configuration were 0.0225″ over the guide wire shaft  35  and 0.0245″ over the marker band  30 . 
     FIG. 2 shows the present invention. The proximal end of the balloon  15  is affixed to the distal end of the shaft  20 . The guide wire shaft  35  is coaxially disposed within the shaft  20 , extending through the balloon  15  with the distal end of balloon  15  being bonded to the distal end of the guide wire shaft  35 . For the Balloon  15  any conventional material may be used such as Nylon, polyethylene (PE) or polyethylene terephthalate (PET). The balloon typically has one or more marker bands  30  made of a material such as platinum/iridium for visualization under fluoroscopy. Those skilled in the art would recognize that any conventional balloon design would be suitable. The balloon  15  is in fluid communication with the inflation lumen  75 . The bonding of the balloon can be any conventional means such as adhesive  80 , heat bonding or welding. The preferred means is to place a ring of U.V. adhesive, as for example #3311 Loctite® (manufactured by Loctite Corp. in Hartford Conn.). 
     The outer diameter of the shaft  20  is approximately 0.038 inches (0.96 mm) with an inner diameter of 0.0280 inches, forming an inflation lumen  75 . The shaft  20  may be formed of either a stiff material for pushability (such as polyimide or poly ether ether ketone (PEEK)) or more flexible material for better tracking (such as Polyethylene (PE) or Nylon). The shaft  20  may also be made of a combination of stiff and flexible materials such that the proximal end is stiffer than the distal end. Those skilled in the art would recognize that any material which has high column strength in a thin walled configuration of the appropriate size would be suitable. The shaft  20  may have several visual marker bands  85  to indicate the various approaches, as for example, the brachial approach. 
     The guide wire shaft  35  is constructed from both High Density Polyethylene (HDPE) and crosslinked and expanded Low Density Polyethylene (LDPE). The guide wire shaft  35  has an inner diameter of 0.016 inches (0.41 mm) suitable for passing standard 0.014 inch (0.36 mm) guide wires. Those skilled in the art would recognize that the dimension varies depending on the application and the size of device being passed. The outer diameter of the guide wire shaft  35  is 0.023 inches. The distal end of the guide wire shaft  35  forms the catheter tip  55 . 
     FIG. 3 shows the construction of the guide wire shaft  35 . The imbedded marker bands  30  are located on a mandrel  70 . The proximal portion  45  of the guide wire shaft  35  is constructed from HDPE and extends from inside of the proximal end of the balloon  15  to the manifold  25 . The distal portion  50  of guide wire shaft  35  is constructed from both HDPE and LDPE and extends from the distal end of proximal portion  45  to the distal end of the catheter  10  forming the catheter tip  55 . The distal portion  50  is formed with an inner layer  60  and an outer layer  65 . The distal end of the proximal portion  45  is slid on the mandrel  70 . The inner layer  60  is made from HDPE and is positioned over the marker bands  30  and the proximal end of the inner layer  60  overlaps the distal end of the proximal portion  45  by 0.039 inches (1.0 mm). The outer layer  65  is made from LDPE and is positioned over the inner layer  60  and the proximal end of the outer layer  65 , covering the distal end of the proximal portion  45  approximately 0.197 inches (5 mm). The distal end of the proximal portion  45 , the inner layer  60  and the outer layer  65  are then heated to 300-320° F., melting the inner layer  60  and the outer layer  65  onto the mandrel, covering and imbedding the marker bands  30  and bonding the inner layer  60  and the outer layer  65  to the proximal portion  45 , forming the guide wire shaft  35 . 
     FIGS. 4 &amp; 5 show catheter  110  which is comprised of a balloon  115 , shaft  120 , and manifold  125 . Marker bands  130  are located inside of the balloon  115 . The marker bands  130  are required to position the balloon  115  using fluoroscopy during an angioplasty procedure. A conventional over-the-wire design consists of a guide wire shaft  135  which defines a guide wire lumen  140  running the length of the catheter  110  inside of the shaft  120 . 
     FIG. 5 shows the present invention. The proximal end of the balloon  115  is affixed to the distal end of the shaft  120 . The guide wire shaft  135  is coaxially disposed within the shaft  120 , extending through the balloon  115  with the distal end of balloon  115  being bonded to the distal end of the guide wire shaft  135 . For the Balloon  115  any conventional material may be used such as nylon, polyethylene (PE) or polyethylene terephthalate (PET). The balloon typically has one or more marker bands  130  made of a material such as platinum/iridium for visualization under fluoroscopy. Those skilled in the art would recognize that any conventional balloon design would be suitable. The balloon  115  is in fluid communication with the inflation lumen  175 . The bonding of the balloon can be any conventional means such as adhesive  180 , heat bonding or welding. The preferred means is to place a ring of U.V. adhesive, as for example #3311 Loctite® (manufactured by Loctite Corp. in Hartford Conn.). 
     The outer diameter of the shaft  120  is approximately 0.038 inches (0.96 mm) with an inner diameter of 0.0280 inches, forming an inflation lumen  175 . The shaft  120  may be formed of either a stiff material for pushability or more flexible material for better tracking (such as Polyethylene (PE) or Nylon). The shaft  120  may also be made of a combination of stiff and flexible materials such that the proximal end is stiffer than the distal end. Those skilled in the art would recognize that any material which has high column strength in a thin walled configuration of the appropriate size would be suitable. The shaft  120  may have several visual marker bands  185  to indicate the various approaches, as for example, the brachial approach. 
     The guide wire shaft  35  has an inner diameter of 0.016 inches (0.41 mm) suitable for passing standard 0.014 inch (0.36 mm) guide wires. Those skilled in the art would recognize that the dimension varies depending on the application and the size of device being passed. The outer diameter of the guide wire shaft  135  is 0.023 inches. The distal end of the guide wire shaft  135  forms the catheter tip  155 . 
     FIG. 6 shows the construction of the guide wire shaft  135 . The guide wire shaft  135  is constructed from nylon and is made in two portions, a proximal portion  145  and a distal portion  150 . The imbedded marker bands  130  are located on a mandrel  170 . The proximal portion  145  of the guide wire shaft  135  extends from inside of the proximal end of the balloon  115  to the manifold  125 . The distal portion  150  of guide wire shaft  135  extends from the distal end of proximal portion  145  to the distal end of the catheter  110  forming the catheter tip  155 . Proximal portion  145  and distal portion  150  can either be made of the same nylon or nylon having different properties, depending on what stiffness is desired The distal end of the proximal portion  145  is slid on the mandrel  170 . The distal portion  150  is positioned over the marker bands  30  and butts the distal end of the proximal portion  145 . The distal end of the proximal portion  45  and the distal portion  150  are then heated to 330-350° F., melting the distal portion onto the mandrel, covering and imbedding the marker bands  130  and bonding to the proximal portion  145 , forming the guide wire shaft  135 . 
     Whereas Applicant&#39;s invention depicts an imbedded marker band for an over-the-wire coronary catheter those skilled in the art would recognize that the imbedded marker bands could be used for any catheter including rapid exchange or fixed wire catheters and other applications such as peripheral etc. The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the scope of the appended claims. 
     
       
         
               
               
             
           
               
                   
               
               
                 No. 
                 Component 
               
               
                   
               
             
             
               
                 10 
                 Catheter 
               
               
                 15 
                 Balloon 
               
               
                 20 
                 Shaft 
               
               
                 25 
                 Manifold 
               
               
                 30 
                 Balloon Marker Bands 
               
               
                 35 
                 Guide Wire Shaft 
               
               
                 40 
                 Guide Wire Lumen 
               
               
                 45 
                 Proximal Portion 
               
               
                 50 
                 Distal Portion 
               
               
                 55 
                 Catheter Tip 
               
               
                 60 
                 Inner Layer 
               
               
                 65 
                 Outer Layer 
               
               
                 70 
                 Mandrel 
               
               
                 75 
                 Inflation Lumen 
               
               
                 80 
                 Adhesive 
               
               
                 85 
                 Shaft Visual Marker Bands 
               
               
                 110 
                 Catheter 
               
               
                 115 
                 Balloon 
               
               
                 120 
                 Shaft 
               
               
                 125 
                 Manifold 
               
               
                 130 
                 Balloon Marker Bands 
               
               
                 135 
                 Guide Wire Shaft 
               
               
                 140 
                 Guide Wire Lumen 
               
               
                 145 
                 Proximal Portion 
               
               
                 150 
                 Distal Portion 
               
               
                 155 
                 Catheter Tip 
               
               
                 170 
                 Mandrel 
               
               
                 175 
                 Inflation Lumen 
               
               
                 180 
                 Adhesive 
               
               
                 185 
                 Shaft Visual Marker Bands