Patent ID: 8551129

Claim:
A device for treating a coronary stenosis comprising: a catheter having a distal end and a proximal end and a longitudinal axis and an inner surface and an outer surface; further comprising a sliding retractable knife assembly located in said distal end comprising: a knife blade comprising a sharpened edge, a top edge, a lower control pin and an upper control pin, both said upper and lower control pins mounted and protruding through said knife blade proximate to and in line substantially parallel to said top edge, said lower pin being proximate to said sharpened edge; further comprising a knife slot through said catheter running parallel with said longitudinal axis, said knife slot being sized so that said knife blade may pass closely edgewise within said knife slot; further comprising a first rail and a second rail each approximately equal in length to said knife slot, said rails fixedly mounted one on either side of said knife slot; said rails each having an inner side facing said knife slot; said first and second track rail inner sides each further comprising an upper pin slot and a lower pin slot; all the said pin slots running substantially parallel to said longitudinal axis and adapted to slidably receive said first and second pins; said knife blade having a first retracted position with said sharpened edge proximate to and parallel to said knife slot and said knife blade being disposed between said first and second track rails with said upper control pin engaged within said first and second upper pin slots respectively and said lower control pin engaged within said first and second lower pin slots respectively; said knife blade further comprising a control wire rotatably attached to said lower control pin, said wire running from said lower control pin through said catheter to said proximate end of said catheter, operable by pulling on said lower control pin toward said the proximal end to cause movement of said knife blade in the proximal direction, and said upper control pin sliding thereby in said upper pin slots operable to cause said knife blade to rotate so as to position said sharpened edge outwardly through said knife slot approximately normal to said outer surface, with continued movement in the proximal direction and continued pulling on said control pin causes said knife blade to move the length of the knife slot wherein said upper control pin moving in said upper control slots is operable to rotate said knife blade into a second retracted position similar to said first retracted position.