Double helix reinforced catheter
The intravascular catheter has two segments; a proximal segment with high stiffness and a distal segment with lower stiffness. The catheter can also have an intermediate segment of lower stiffness than the proximal segment and higher stiffness than the distal segment. The catheter comprises a polymeric inner tube, a reinforcing inner jacket which is spirally wound over the inner tube and which becomes progressively softer from a proximal end to a distal end, and a polymeric outer sheath extruded over the inner jacket according to the teachings of U.S. Pat. No. 5,445,624. The reinforcing jacket comprises helical coiled wires or fibers of various materials and layers wound over the inner tube in order to provide improved multi-axial mechanical properties, such as torque, compression, tension and anti-kinking characteristics. Stainless steel, carbon, glass, platinum, platinum/tungsten or palladium wire in either oval, round or flat geometry are used together with single or dual layers to achieve a graduated stiffness with the reinforcing jacket being stiffer at a proximal end and softer at a distal end. Methods for making the catheter and for annealing ends of the wound wire are also disclosed.
1. An intravascular catheter comprising:
a polymeric inner tube having an internal lumen and proximal and distal segments;
a distal reinforcing jacket including a first helical coiled wire formed of a first material wound over the surface of said distal segment; and
a proximal reinforcing jacket including a second helical coiled wire and a third helical coiled wire, said second helical coiled wire being formed of a second material wound over the surface of said proximal segment and over said first helical coil, said third helical coiled wire being formed of the second material and wound over said second helical coiled wire and said proximal segment, said second helical coiled wire extending distally beyond said third helical coiled wire, such that said distal reinforcing jacket has a first stiffness, wherein said first stiffness of said distal reinforcing jacket results from said first helical coiled wire alone, said proximal reinforcing jacket has a second stiffness and said first stiffness is relatively lower than said second stiffness, wherein said second stiffness of said proximal reinforcing jacket results from combination of said second and third helical coiled wires, and whereby said first helical coiled wire and said second helical coiled wire overlap to form an intermediate reinforcing jacket having a resulting stiffness approximately halfway between said first stiffness and said second stiffness, and wherein said stiffness of said intermediate reinforcing jacket approximately halfway between said first stiffness from said first helical coiled wire alone and said second stiffness from said combination of said second and third helical coiled wires results from combination of said first and second helical coiled wires.
2. An intravascular catheter comprising:
a polymeric inner tube having an internal lumen and proximal and distal segments;
a proximal reinforcing jacket covering the surface of said proximal segment, said proximal reinforcing jacket comprising a first inner wire layer and a second outer wire layer separate from said first inner wire layer, and said coiled wires of said second outer wire layer being wound over said first layer and being made of a second material, said first inner wire layer of said proximal reinforcing jacket extending distally of said proximal segment;
a distal reinforcing jacket covering the surface of said distal surface, said distal reinforcing jacket comprising a single layer of helical coiled wire formed of a third material, said third material being different from said first material and said first material being relatively stiffer than said third material, such that said distal reinforcing jacket has a first stiffness, wherein said first stiffness of said distal reinforcing jacket results from said single layer of helical coiled wire alone, said proximal reinforcing jacket has a second stiffness and said first stiffness is relatively lower than said second stiffness, said second stiffness of said proximal reinforcing jacket results from combination of said first inner wire layer and said second outer wire layer, and said distal reinforcing jacket extending proximally of said distal segment, whereby said first inner wire layer of said proximal reinforcing jacket and said distal reinforcing jacket overlap to form an intermediate reinforcing jacket having a resulting stiffness approximately halfway between said first stiffness and said second stiffness, and wherein said stiffness of said intermediate reinforcing jacket approximately halfway between said first stiffness from said single layer of helical coiled wire and said second stiffness from said combination of said first inner wire layer and said second outer wire layer results from combination of said first inner wire layer and said single layer of helical coiled wire of said distal reinforcing jacket.