A catheter device including an elongate tubular shaft having a consistent material composition for a substantial proportion of its length. The device includes a proximal shaft portion having a first flexibility and a distal shaft portion having a second flexibility, wherein the second flexibility is greater than the first flexibility and wherein at least the distal shaft portion comprises at least one score in a surface thereof. The device includes a wholly external wire guide structure secured to the tubular shaft by a figure-eight polymer sleeve.