A tissue-removing catheter for removing tissue from a body lumen during a cutting operation thereof, the tissue-removing catheter comprising: an elongate catheter body configured for insertion into the body lumen, the catheter body having opposite distal and proximal portions, and a longitudinal axis extending between the distal and proximal portions; a tissue-removing element located generally at the distal portion of the catheter body for rotation generally about the longitudinal axis of the catheter body; an electric motor operably connected to the tissue-removing element for imparting rotation of the tissue-removing element about a rotational axis during the cutting operation of the catheter, wherein a rotational speed of the tissue-removing element is selectively adjustable; a sensor configured to detect a linear advancement speed of the catheter body in the body lumen during the cutting operation of the catheter; a motor control circuit in electrical communication with the sensor and the motor, wherein during an operational control function, the motor control circuit is configured to: receive a signal from the sensor indicative of the detected linear advancement speed of the catheter body in the body lumen during the cutting operation of the catheter, determine whether the received signal is indicative of the detected linear advancement speed of the catheter body being different than a threshold linear advancement speed based on a rotational speed of the tissue-removing element, and adjust the rotational speed of the tissue-removing element to increase efficiency of the tissue-removing element if the received signal is indicative of the detected linear advancement speed of the tissue-removing element being different than the threshold linear advancement speed. an elongate catheter body configured for insertion into the body lumen, the catheter body having opposite distal and proximal portions, and a longitudinal axis extending between the distal and proximal portions; a tissue-removing element located generally at the distal portion of the catheter body for rotation generally about the longitudinal axis of the catheter body; an electric motor operably connected to the tissue-removing element for imparting rotation of the tissue-removing element about a rotational axis during the cutting operation of the catheter, wherein a rotational speed of the tissue-removing element is selectively adjustable; a sensor configured to detect a linear advancement speed of the catheter body in the body lumen during the cutting operation of the catheter; a motor control circuit in electrical communication with the sensor and the motor, wherein during an operational control function, the motor control circuit is configured to: receive a signal from the sensor indicative of the detected linear advancement speed of the catheter body in the body lumen during the cutting operation of the catheter, determine whether the received signal is indicative of the detected linear advancement speed of the catheter body being different than a threshold linear advancement speed based on a rotational speed of the tissue-removing element, and adjust the rotational speed of the tissue-removing element to increase efficiency of the tissue-removing element if the received signal is indicative of the detected linear advancement speed of the tissue-removing element being different than the threshold linear advancement speed. receive a signal from the sensor indicative of the detected linear advancement speed of the catheter body in the body lumen during the cutting operation of the catheter, determine whether the received signal is indicative of the detected linear advancement speed of the catheter body being different than a threshold linear advancement speed based on a rotational speed of the tissue-removing element, and adjust the rotational speed of the tissue-removing element to increase efficiency of the tissue-removing element if the received signal is indicative of the detected linear advancement speed of the tissue-removing element being different than the threshold linear advancement speed.