A rotational atherectomy device for abrading a stenotic lesion from a vessel of a patient comprises a flexible drive shaft (1) which extends towards a distal end 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 to the drive shaft proximal to and spaced away from the distal fluid inflatable support element. Both the abrasive element and the distal fluid inflatable support element are rotatable together with the drive shaft and the drive shaft comprises a torque transmitting coil (2) which defines a long lumen of the drive shaft. The distal fluid inflatable support element is formed from a fluid impermeable membrane (9, 9″) that crosses a longitudinal axis (x-x) common to the torque transmitting 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 shaft from entering the vessel in the direction of said longitudinal axis so that fluid has to pass through the fluid inflatable support element, inflating said support element and exiting from the device through an outflow opening (66) in the fluid inflatable support element in a direction different from the direction of the longitudinal axis of the coil and the lumen.