Atherectomy catheter

DETAILED DESCRIPTION An atherectomy catheter is disclosed for removing plaque, stenosis, occlusions, or the like from an artery or coronary vessel.
The catheter comprises a flexible hollow tube housing a positive displacement motor at its distal end.
A cutting element is connected to the positive displacement motor and is rotated thereby.
The hollow tube is concentrically located within an outer tube, the ends of which are connected to a pump.
An annulus or return passage is defined between the inner and outer tubes.
The positive displacement motor is driven by pressurized fluid flowing through the inner tube past the drive motor and returning through the return passage defined between the inner and outer tubes to the pump, thereby defining a closed loop hydraulic system.
Fluid pressure and velocity is converted into rotary motion to rotate the cutting element.