A spin-to-open rotational atherectomy system, comprising: an elongated, flexible helically coiled drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient and having a lumen therethrough, wherein: the helical coils of the drive shaft configured to enable the drive shaft to rotate in a spin-to-open direction during highspeed rotation, the drive shaft having a nominal outer diameter and length and a maximum allowed outer diameter limit; a guidewire adapted to translate and rotate within the lumen of the drive shaft and to allow the drive shaft to translate and rotate over the guidewire; an abrasive crown attached to the drive shaft proximate the distal end of the drive shaft; and an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in the spin-to-open direction, wherein when a blockage is encountered, the outer diameter of the drive shaft increases and the length of the drive shaft decreases; further comprising: a control unit comprising control electronics adapted to monitoring and controlling the rotation of the electric motor and drive shaft and comprising a maximum limit for torque applied by the electric motor to the drive shaft, a maximum current limit used by the electric motor and a minimum rotational speed limit for the rotating drive shaft, wherein the maximum limits for torque, maximum current and/or minimum rotational speed are correspondent with the maximum limit for the outer diameter of the drive shaft, wherein the control electronics eliminate power to the electric motor when the maximum limit of the outer diameter of the drive shaft is reached so that no torque-induced rotation is transferred from the electric motor. an elongated, flexible helically coiled drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient and having a lumen therethrough, wherein: the helical coils of the drive shaft configured to enable the drive shaft to rotate in a spin-to-open direction during highspeed rotation, the drive shaft having a nominal outer diameter and length and a maximum allowed outer diameter limit; a guidewire adapted to translate and rotate within the lumen of the drive shaft and to allow the drive shaft to translate and rotate over the guidewire; an abrasive crown attached to the drive shaft proximate the distal end of the drive shaft; and an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in the spin-to-open direction, wherein when a blockage is encountered, the outer diameter of the drive shaft increases and the length of the drive shaft decreases; the helical coils of the drive shaft configured to enable the drive shaft to rotate in a spin-to-open direction during highspeed rotation, the drive shaft having a nominal outer diameter and length and a maximum allowed outer diameter limit; a guidewire adapted to translate and rotate within the lumen of the drive shaft and to allow the drive shaft to translate and rotate over the guidewire; an abrasive crown attached to the drive shaft proximate the distal end of the drive shaft; and an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in the spin-to-open direction, wherein when a blockage is encountered, the outer diameter of the drive shaft increases and the length of the drive shaft decreases; further comprising: a control unit comprising control electronics adapted to monitoring and controlling the rotation of the electric motor and drive shaft and comprising a maximum limit for torque applied by the electric motor to the drive shaft, a maximum current limit used by the electric motor and a minimum rotational speed limit for the rotating drive shaft, wherein the maximum limits for torque, maximum current and/or minimum rotational speed are correspondent with the maximum limit for the outer diameter of the drive shaft, wherein the control electronics eliminate power to the electric motor when the maximum limit of the outer diameter of the drive shaft is reached so that no torque-induced rotation is transferred from the electric motor.