Abstract: A stent for placement in a blood vessel of a patient, the stent including: a proximal end, a distal end, and a generally circular cross-section with a diameter; a Micro Electro-Mechanical System (MEMS) ultrasound sensor using a Doppler principle for determining patency and flow rate through the cross-section, and pressure drop from the proximal end to the distal end; a transmitter for providing signals to an external receiver outside the patient's body; and a coil device for receiving energy from outside the patient's body and coupled to the transmitter for powering the transmitter.