Patent ID: 8118804

Claim:
A catheter assembly used for treatment of a blood vessel of the head or neck, said catheter assembly comprising: an outer catheter comprised of an outer catheter body and an outer catheter hub at a proximal portion of the outer catheter body; an inner catheter comprised of: an inner catheter body possessing an outer circumference configured to allow the inner catheter body to be positioned inside the outer catheter body; a tip at a distal-most portion of the inner catheter body, the tip being softer that the distal portion of the inner catheter body; and an inner catheter hub at a proximal portion of the inner catheter body and configured to be coupled to the outer catheter hub in a coupled condition by way of a lock which holds the inner and outer catheter bodies in a coupled condition; the inner catheter body comprising: a flexible section having a distal end to which is fixed the tip; a physical property transition section on a proximal side of the flexible section; a first body section on the proximal side of the physical property transition section, a second body section on the proximal side of the first body section; the second body section possessing a flexural rigidity greater than the flexural rigidity of the first body section; the second body section comprising a reinforcing material layer embedded in material of which the second body section is made, and the reinforcing material layer being made of a material different from the material of which the second body section is made; relationships of 1<σ 2X /σ 1 ≦2 and 1<σ 3 /σ 2Y ≦2 are satisfied, where σ 1 [gf] is the flexural rigidity of the flexible section of the inner catheter body in water at a temperature of 37° C., σ 2X [gf] is the flexural rigidity of a distal portion of the physical property transition section, σ 2Y [gf] is the flexural rigidity of a proximal portion of the physical property transition section, and σ 3 [gf] is the flexural rigidity of the first body section; the inner catheter and the outer catheter each possessing a length such that with the inner catheter positioned inside the outer catheter and the outer catheter hub and the inner catheter hub coupled to each other in the coupled condition by the lock, a distal portion of the second body section protrudes distally beyond a distal-most end of the outer catheter body; wherein said first body section, said physical property transition section, said flexible section and said tip are distal to said distal portion of the second body section, whereby said first body section, said physical property transition section, said flexible section and said tip also protrude distally beyond a distal-most end of the outer catheter body; and the flexural rigidity of a distal portion of the outer catheter body is higher than the flexural rigidity of the second body section.