An improved catheter assembly and method are provided for treating bifurcated vessels. The catheter assembly of the present invention includes a tubular sheath for restraining dual balloons normally biased apart. Withdrawal of the sheath allows the balloons to separate and deploy intravascular stents in a bifurcated vessel. The catheter assembly also includes the feature of containing two guide wire lumens in a single catheter designed to track over a single wire prior to arrival at the bifurcation, thus preventing wire wrapping and crossing of the wires.