US Patent 10300253 Weeping balloon with flow channels for reduced infusion pressure

Method of forming a multiple balloon catheter includes extruding a tube and a plurality of ribs through a die to form a monolithic element that spans between first and second ends with the plurality of ribs extending along the length of the tube to define a corresponding number of a plurality of channels that extend along the length of the tube. Positioning a portion of the tube into a mold and constricting a proximal end portion and a distal end portion of the tube that is positioned in the mold. Inflating the tube to produce an inner balloon having a body portion that spans between proximal and distal end portions and cutting the inner balloon to separate the inner balloon from a remainder of the tube. Disposing an outer balloon including a plurality of holes around the inner balloon and aligning the plurality of holes with the plurality of channels.