Disclosed herein is a catheter device for treatment of disease in biological conduits. The device has inner and outer coaxial catheter members, each having an inflatable balloon attached near its distal end. When the balloons are inflated, a sealed treatment chamber is created between the balloons. The length of the treatment chamber is adjustable by sliding the coaxial catheter members with respect to each other to obtain a desired separation between the attached balloons before inflation. Biological debris is trapped within the chamber and removed by infusion and aspiration of a flushing fluid, reducing the risk of myocardial infarction. Adjunctive treatment devices can be inserted into the sealed treatment chamber through a lumen of the outer coaxial member.