An improved laser catheter system includes a flexible catheter tube having proximate and distal ends. The distal end, which is intended for inserting into a patient's artery, is axially split into at least two segments. Optical waveguides extend the length of the catheter tube and terminate at the distal end, with at least one waveguide secured to each of the spreadable segments. A mechanism is provided for spreading the segments while the catheter is implaced in the patient. Conveniently, a balloon catheter may be used by inserting it into the lumen of the laser catheter so that the balloon tip lies within the spreadable segments. By then inflating the balloon, the spreadable segments are spread apart as desired.