Patent ID: 7413558

Claim:
An incising device for use on a medical catheter to incise biological material at a treatment site, said incising device comprising: a balloon defining a balloon axis, said balloon being inflatable from a first deflated configuration to a second radially expanded configuration; an elongated incising element having an incising tip and mounted on said balloon to extend radially therefrom when said balloon is in said radially expanded configuration; and an elastic folding member having a substantially tubular shape when said folding member is in a relaxed state, said folding member being bonded to said outer surface of said balloon and sized to cover said tip when said balloon is deflated, said folding member being oriented on said balloon and formed with an axially aligned slit, with said folding member deforming in response to a balloon inflation to expose said incising tip for incision of the biological material; wherein said folding member extends from a first axially aligned edge to a second axially aligned edge and said incising element is positioned closer to said first edge than said second edge to overlap said first and second edges when said balloon is in said deflated configuration.