Balloon dilatation catheter having a free core wire

Claim 1

A catheter adapted to be inserted into a patient's vascular system, the catheter comprising: an elongate flexible tubular member having an interior passage extending from a proximal end to a distal end; a guiding member having a proximal end and a distal end, the proximal end of the guiding member being coupled to and fixed against rotational movement relative to the tubular member, the guiding member extending distally beyond the distal end of the tubular member; a flexible waist tube having a proximal end and a distal end, the waist tube being more flexible than the tubular member, the waist tube having its proximal end sealably connected to the tubular member, the waist tube extending distally beyond the distal end of the tubular member about the guiding member to define a distal interior passage in fluid communication with the interior passage of the tubular member; an inflatable balloon member extending around a section of the guiding member and having an interior in fluid communication with the interior passages, the balloon member including a proximal end sealably connected to the distal end of the waist tube and a distal end free from any fixed connection to the guiding member; an axially stiff component coupled to the balloon member so as to allow rotational movement of the guiding member relative to the balloon member such that torque applied through the guiding member is not readily transmitted to the balloon member from the guiding member, the axially stiff component is an inner sleeve having a proximal end, a distal end, and a through lumen that extends between the proximal and distal ends of the inner sleeve, the inner sleeve exhibiting a substantial degree of column strength to resist axial buckling when the catheter is advanced through a patient's vascular system, and the distal end of the inner sleeve is secured to the distal end of the balloon member, and the through lumen of the inner sleeve is dimensioned to freely receive the guiding member and to define a cylindrical gap between an interior wall of the inner sleeve and an exterior surface of the guiding member, the cylindrical gap having minimum radial dimension to provide resistance to flow of pressurized balloon fluid, to minimize leakage through the inner sleeve and distal end of the balloon member; and push means associated with the guiding member and cooperable with the axially stiff component for preventing a longitudinal collapse of the balloon member in a proximal direction when the catheter is advanced through a patient's vascular system.