Patent ID: 8162879

Claim:
A catheter system for site-specific delivery of a therapeutic agent to a blood vessel of a patient comprising: a. an elongated shaft assembly having an inner shaft, an outer shaft, a distal end, and a proximal end; b. proximal and distal vessel-conforming balloons, each of the proximal and distal balloons being separately positionable and inflatable to restrict blood flow in the vessel, the proximal and distal balloons defining a treatment window of a defined but variable length for delivery of the therapeutic agent; c. at least one marker band adjacent to the proximal balloon and at least one marker band adjacent to the distal balloon; d. the outer shaft defining a drug delivery lumen and at least one delivery aperture, the drug delivery lumen and the at least one delivery aperture being in fluid communication to deliver the therapeutic agent to the treatment window; e. the inner shaft defining a distal opening, a drug passing lumen, and at least one distal leak aperture; the distal opening, the drug passing lumen, and the at least one distal leak aperture being in fluid communication to form a distal leak path; the at least one distal leak aperture being disposed in the treatment window to allow fluid within the treatment window to exit the treatment window through the distal leak path as the therapeutic agent is delivered to the treatment window through the drug delivery lumen so as to provide a homogeneous concentration of the therapeutic agent to the treatment window; and f. a guidewire configured to block the at least one distal leak aperture and being movably positioned within the elongated shaft assembly between first and second positions such that movement of the guidewire to one of the first and second positions closes the at least one distal leak aperture to isolate the therapeutic agent within the treatment window and movement of the guidewire to the other of the first and second positions exposes the at least one distal leak aperture to permit the fluid disposed in treatment window to pass from the treatment window.