Active cutting catheter with housed expandable actuator

An apparatus for slicing or scoring a lesion in a vessel, comprising:

• a catheter including a shaft having a distal portion supporting a housing, the housing including first lateral passage;
• a cutter adapted for moving from a retracted position within the housing to a deployed position for at least partially projecting from the first lateral passage;
• an expandable actuator within the housing for actuating the cutter to move from the retracted position to the deployed position, wherein the expanable actuator comprises an inflatable balloon;
• wherein the cutter is pivotably mounted to the housing about a pivot point external to the expandable actuator for moving between the retracted position and the deployed position;
• further including a first link for urging the cutter toward the deployed position when the inflatable balloon is expanded to contact the first link;
• and
• further including a second link connected to the first link and rotatably connected to a distal end of the cutter;
• wherein the second link includes an adjustable projection for pushing the cutter to the deployed position when the inflatable balloon is expanded to engage the first link.