A rotational atherectomy device for abrading a stenotic lesion from a vesselof a patient comprises a flexible drive shaft (1) which extends towards a distalend of the device, a distal fluid inflatable support element (3, 3)located at a distal end of the drive shaft and an abrasive element (5) mounted tothe drive shaft proximal to and spaced away from the distal fluid inflatable supportelement. Both the abrasive element and the distal fluid inflatable support elementare rotatable together with the drive shaft and the drive shaft comprises a torquetransmitting coil (2) which defines a long lumen of the drive shaft. The distalfluid inflatable support element is formed from a fluid impermeable membrane(9, 9) that crosses a longitudinal axis (x-x) common to the torquetransmitting coil and the lumen of the drive shaft at the distal end of the device,thereby preventing pressurized fluid flowing along the lumen of the drive shaftfrom entering the vessel in the direction of said longitudinal axis so that fluidhas to pass through the fluid inflatable support element, inflating said supportelement and exiting from the device through an outflow opening (66) in the fluidinflatable support element in a direction different from the direction of thelongitudinal axis of the coil and the lumen.
