Systems and methods for estimating a position of a heart pump
Systems and methods are provided herein for estimating a position of a heart pump system in a patient. The system receives first data indicative of a time-varying motor current during a first time period. The motor current corresponds to an amount of current delivered to a motor, while the heart pump system is operating in the patient. The system receives second data indicative of a time-varying differential pressure during the first time period. The differential pressure is indicative of a position of the heart pump system relative to patient's heart. The system receives third data indicative of time-varying motor current during a second time period, and determines an estimate of differential pressure during the second period of time from the third data and a relationship between the first data and the second data. The estimate is usable to predict the position of the heart pump system in the patient.
1. A heart pump system comprising:
a pump comprising a pump housing and a rotor, the pump housing having a proximal end and a distal end, and the pump being configured to be operated by a motor;
a cannula comprising a proximal end and a distal end, wherein the proximal end of the cannula interfaces with the distal end of the pump housing;
an elongate catheter extending proximal of the pump housing;
one or more sensors, including a differential pressure sensor; and
a controller configured to:
receive a first data indicative of a time-varying motor current during a first period of time while the heart pump system is operating in a patient, wherein the time-varying motor current corresponds to an amount of current delivered to the motor;
receive a second data indicative of a time-varying differential pressure measured by the differential pressure sensor during the first period of time, wherein the time-varying differential pressure corresponds to a difference in pressure between an inner portion of the heart pump system and an outside of the heart pump system and is further indicative of a position of the heart pump system relative to patient's heart;
receive a third data indicative of time-varying motor current during a second period of time while the heart pump system is operating in the patient, wherein the second period of time is later than the first period of time;
determine that the differential pressure sensor has failed when no data is received from the differential pressure sensor during the second period of time; and
determine, in response to determining that the differential pressure sensor has failed, an estimate of time-varying differential pressure during the second period of time from the third data and a relationship between the first data and the second data,
wherein the estimate of time-varying differential pressure during the second period of time is usable to predict the position of the heart pump system in the patient.
2. The heart pump system of claim 1 , wherein the pump is configured to be placed such that the cannula extends across an aortic valve of the patient, the distal end of the cannula being located within a left ventricle of the patient, and the proximal end of the cannula being located within an aorta of the patient.
3. The heart pump system of claim 1 , further comprising a flexible projection extending distally away from the distal end of the cannula.
4. The heart pump system of claim 1 , wherein the elongate catheter is coupled on its distal end to the pump housing, and wherein the pump further comprises a drive cable extending through the elongate catheter.
5. The heart pump system of claim 1 , wherein the controller is further configured to:
provide a first indicator that the differential pressure sensor has failed; and
provide a second indicator that the estimate of time-varying differential pressure during the second period of time is simulated.
6. The heart pump system of claim 1 , wherein the controller is further configured to determine the time-varying differential pressure is drifting by:
comparing the time-varying differential pressure to the estimate of time-varying differential pressure for the second period of time;
calculating, based on comparing the time-varying differential pressure to the estimate of time-varying differential pressure, a difference between the time-varying differential pressure and the estimate of time-varying differential pressure over the second period of time;
comparing the difference to a differential pressure signal threshold; and
determining, based on comparing the difference to the differential pressure signal threshold, the difference is greater than the differential pressure signal threshold.