A balloon catheter is formed with a plurality of depressions. The balloon is coated with a matrix incorporating a therapeutic substance, which additionally fills the depressions. When the balloon is expanded within a body lumen, the therapeutic substance may diffuse into the lumen wall, or all or a portion of the coating transfers to the lumen wall. A lattice frame may surround the balloon, applied prior to coating if the coating is to transfer, operative to maintain a more linear balloon profile during inflation, promoting more even transfer pressure. A contrast dye is incorporated into the transferred coating, enabling ready location and inspection of the treated lumen area. Projections may alternately be formed in the balloon surface, operative to urge the coating and therapeutic substance between cells, or past cell layers of the lumen, to the interior of the lumen wall. Prior to transfer, an extended inflation period, possibly including the use of perfusion ports to maintain blood supply, enables a larger initial quantity of therapeutic substance to diffuse into the body lumen, prior to transfer of the coating and withdrawal of the catheter, balloon, and frame.
