Introducer sheath

Abstract

Introducer sheath ( 10, 30, 40 ) having a flexible kink-resistant distal tip portion ( 26, 32, 42 ). A multilayer sheath structure is used, with an inner tube ( 12 ) such as PTFE having a coil ( 14 ) of wire wound therearound. A first length of outer tubing ( 20 ) such as of nylon is inserted over most of the coil-wound inner tube ( 12 ) in a manner exposing a distal length of coil-wound inner tube. A second length of outer tubing ( 22 ) with a softer durometer than first outer tubing length ( 20 ), is inserted over the exposed coil-wound inner tube and extends for a slight distance beyond the end of the coil. During heat application, the outer tubing lengths ( 20, 22 ) are melted to bond to each other and to flow between the spacings of the coil turns to bond to the roughened outer surface of the inner tube ( 12 ). The distal tip region corresponding to the second tubing length is flexible and is kink-resistant due to the coil ( 14 ).

What is claimed is:  
     
         1 . An intravascular sheath comprising: 
 an inner tube extending to a distal end;    a wire coil wound around said inner tube extending to an end spaced proximally from said inner tube distal end;    a first outer tube disposed around said wire coil and said inner tube therewithin to a first outer tube distal end spaced proximally from said wire coil distal end such that a distal end portion of said wire coil extends distally therebeyond; and    at least a second outer tube disposed around said wire coil and said inner tube therewithin extending distally from said first outer tube distal end and covering said distal end portion of said wire coil and extending slightly beyond said distal end of said inner tube,    said first outer tube being of a material having a relatively hard durometer, and said second outer tube being of a material of a substantially softer durometer than said material of said first outer tube.    
     
     
         2 . The intravascular sheath according to    claim 1   , wherein said outer tube and said inner tube are bonded to each other and to said wire coil and to said inner tube between windings of said wire coil.  
     
     
         3 . The intravascular sheath according to    claim 2   , wherein an outwardly facing surface of said inner tube has been roughened to enhance bonding thereto of said first and second outer tubes.  
     
     
         4 . The intravascular sheath according to    claim 2   , wherein said bonding is heat bonding.  
     
     
         5 . The intravascular sheath according to    claim 1   , wherein a radiopaque marker band is affixed to said wire coil distal end within said second outer tube.  
     
     
         6 . The intravascular sheath according to    claim 1   , wherein said second outer tube is polymeric and contains radiopaque filler.  
     
     
         7 . The intravascular sheath according to    claim 6   , wherein said second outer tube contains between about 20% and 85% by weight of radiopaque filler particles.  
     
     
         8 . The intravascular sheath according to    claim 6   , wherein said second outer tube contains about 80% by weight of radiopaque filler particles.  
     
     
         9 . The intravascular sheath according to    claim 1   , wherein said first outer tube is substantially free of radiopaque filler.  
     
     
         10 . The intravascular sheath according to    claim 1   , wherein said second outer tube comprises a material having a durometer of at least 5 D lower than that of the first outer tubing length.  
     
     
         11 . The intravascular sheath according to    claim 10   , wherein said first outer tube comprises a material having a durometer of about 56 D to 58 D.  
     
     
         12 . The intravascular sheath according to    claim 1   , wherein said second outer tube comprises a material having a durometer of between about 10 D and 75 D.  
     
     
         13 . The intravascular sheath according to    claim 12   , wherein said second outer tube comprises a material having a durometer of about 39 D.  
     
     
         14 . The intravascular sheath according to    claim 1   , wherein said first and second outer tubes are distinctly different in color or shade.  
     
     
         15 . The intravascular sheath according to    claim 1   , wherein said wire coil comprises flat wire.  
     
     
         16 . The intravascular sheath according to    claim 1   , wherein a distal tip region of the sheath is arcuate.  
     
     
         17 . The intravascular sheath according to    claim 16   , wherein said arcuate distal tip region has a length of about 1 cm or more.  
     
     
         18 . The intravascular sheath according to    claim 16   , wherein said arcuate distal tip region extends about an angle of about 90°.  
     
     
         19 . The intravascular sheath according to    claim 1   , wherein said wire coil extends for a length of about five millimeters beyond said distal end of said first outer tube.  
     
     
         20 . The intravascular sheath according to    claim 1   , wherein said inner tube is unitarily formed.  
     
     
         21 . An intravascular sheath comprising: 
 an inner tube extending to a distal end;    a wire coil wound around said inner tube extending to an end spaced proximally from said inner tube distal end;    a first outer tube disposed around said wire coil and said inner tube therewithin to a first outer tube distal end spaced proximally from said wire coil distal end such that a distal end portion of said wire coil extends for a length of about 1 cm distally therebeyond; and    a second outer tube distally from said first outer tube distal end and disposed around and covering said distal end portions of said wire coil and said inner tube therewithin and extending slightly therebeyond;    said first outer tube being of a material having a durometer of between about 50 D and 60 D, and said second outer tube being of a material of a durometer of between about 35 D and 45 D;    said second outer tube comprises a radiopaque material;    said wire coil is of flat wire;    said first and second outer tubes are bonded to said inner tube and to said wire coil.