Non-occluding balloon for cardiovascular drug delivery

A catheter apparatus comprising:

• a catheter shaft having a guidewire lumen and an inflation lumen;
• and
• a non-occluding medical balloon operatively mounted to the catheter shaft, the balloon comprising
• a sidewall having an inner surface defining a central passage and an outer surface, the sidewall including at least one inflation passage disposed between the inner and outer surfaces and fluidly isolated from the central passage;
• a proximal perfusion port formed through a proximal end portion of the sidewall that fluidly connects an exterior of the balloon to the central passage without communicating with the at least one inflation passage, and
• a distal perfusion port formed through a distal end portion of the sidewall that fluidly connects the central passage to the exterior of the balloon without communicating with the at least one inflation passage;
• and
• a plurality of micro-pores formed through the outer surface of the sidewall into the at least one inflation passage;
• wherein the plurality of micro-pores have dimensions selected relative to surface tension and/or viscosity of a drug-carrying inflation medium within the at least one inflation passage such that the inflation medium is not emitted from the plurality of micro-pores until a predetermined pressure differential between the at least one inflation passage and an exterior of the balloon is exceeded;
• and
• wherein the inflation lumen is in fluid communication with the at least one inflation passage of the sidewall and the guidewire lumen extends through the central passage.

A method of delivering a drug to tissue of a body lumen, comprising:

• positioning at a treatment site within the body lumen a non-occluding medical balloon comprising
• a sidewall having an inner surface defining a central passage and an outer surface, the sidewall including at least one inflation passage disposed between the inner and outer surfaces and fluidly isolated from the central passage;
• a proximal perfusion port formed through a proximal end portion of the sidewall that fluidly connects an exterior of the balloon to the central passage without communicating with the at least one inflation passage, and
• a distal perfusion port formed through a distal end portion of the sidewall that fluidly connects the central passage to the exterior of the balloon without communicating with the at least one inflation passage;
• and
• a plurality of micro-pores formed through the outer surface of the sidewall into the at least one inflation passage, the plurality of micro-pores having dimensions selected relative to surface tension and/or viscosity of a drug-carrying inflation medium within the at least one inflation passage such that the inflation medium is not emitted from the plurality of micro-pores until a predetermined pressure differential between the at least one inflation passage and an exterior of the balloon is exceeded;
• inflating the balloon by supplying the drug-carrying inflation medium into the at least one inflation passage to press the outer surface of the balloon into contact with the tissue while maintaining blood flow through the central passage via the proximal and distal perfusion ports;
• and
• increasing pressure of the inflation medium above the predetermined pressure differential to emit the inflation medium through the plurality of micro-pores to the tissue.