METHOD AND APPARATUS FOR CALIBRATION AND USE IN ESTIMATING BLOOD FLOW IN AN INTRAVASCULAR BLOOD PUMP

1 - 15 . (canceled)

16 . A method for estimating blood flow in an intravascular blood pump, the method comprising:

retrieving a set of reference data obtained in a test environment, the set of reference data comprising, for at least one rotational speed of a motor at different pressure differences, a respective reference motor current and a respective amount of flow;

measuring, after placement of the intravascular blood pump in a patient, at the at least one rotational speed of the motor at the different pressure differences, a respective patient-specific motor current;

calculating a motor current deviation value as a difference between (a) the respective reference motor current and (b) the respective patient-specific motor current; and

estimating a patient-specific blood flow based on the calculated motor current deviation value.

17 . The method according to claim 16 , wherein measuring the respective patient-specific motor current comprises measuring a maximum amount of motor current drawn by the motor driving the intravascular blood pump.

18 . The method according to claim 17 , wherein the maximum amount of motor current drawn by the motor driving the intravascular blood pump corresponds to an open state of a cardiac valve.

19 . The method according to claim 17 , wherein the maximum amount of motor current drawn by the motor driving the intravascular blood pump corresponds to a pressure difference of zero.

20 . The method according to claim 16 , wherein measuring the respective patient-specific motor current comprises measuring a minimum amount of motor current drawn by the motor driving the intravascular blood pump.

21 . The method according to claim 20 , wherein the minimum amount of motor current drawn by the motor driving the intravascular blood pump corresponds to an open state of a cardiac valve.

22 . The method according to claim 20 , wherein the minimum amount of motor current drawn by the motor driving the intravascular blood pump corresponds to a pressure difference of zero.

23 . The method according claim 16 , further comprising updating the calculated motor current deviation value after a predefined time interval.

24 . The method according to claim 16 , further comprising updating the calculated motor current deviation value in response to detecting at least one influencing characteristic selected from a group of characteristics consisting of: a change in the motor current, a change in a temperature of the blood, a change in a temperature of a purge fluid, a change in a viscosity of the blood, a change in a viscosity of a purge fluid, and a change in a physical characteristic of the intravascular blood pump.

25 . The method according to claim 16 , wherein the set of reference data is obtained in the test environment using a fluid and the intravascular blood pump.

26 . The method according to claim 25 , wherein a temperature of the fluid is between 36° C. and 37° C.

27 . The method according to claim 25 , wherein the fluid is chosen to have a flow behavior of blood.

28 . The method according to claim 25 , wherein the fluid comprises water and glycerol in a mixing proportion providing a viscosity of blood.

29 . The method according to claim 16 , wherein the intravascular blood pump is a cable-driven blood pump.

30 . The method according to claim 16 , wherein the respective patient-specific motor current is measured during systole.

31 . The method according to claim 16 , wherein the set of reference data is obtained in the test environment by simulating curves of a human vessel system.

32 . The method according to claim 16 , wherein the calculated motor current deviation value is added to the respective reference motor current.

33 . The method according to claim 16 , wherein the calculated motor current deviation value is subtracted from the respective reference motor current.

34 . A system comprising:

an intravascular blood pump comprising a motor for driving the intravascular blood pump; and

one or more processors configured to:

retrieve a set of reference data obtained in a test environment, the set of reference data comprising, for at least one rotational speed of the motor at different pressure differences, a respective reference motor current and a respective amount of flow;

measure, after placement of the intravascular blood pump in a patient, at the at least one rotational speed of the motor at the different pressure differences, a respective patient-specific motor current;

calculate a motor current deviation value as a difference between (a) the respective reference motor current and (b) the respective patient-specific motor current; and

estimate a patient-specific blood flow based on the calculated motor current deviation value.

35 . A non-transitory computer readable storage medium having instructions stored thereon that, when executed by one or more processors, cause the one or more processors to:

retrieve a set of reference data obtained in a test environment, the set of reference data comprising at least one rotational speed of a motor of an intravascular blood pump at different pressure differences, a respective reference motor current and a respective amount of flow;

measure, after placement of the intravascular blood pump in a patient, at the at least one rotational speed of the motor at the different pressure differences, a respective patient-specific motor current;

calculate a motor current deviation value as a difference between (a) the respective reference motor current and (b) the respective patient-specific motor current; and

estimate a patient-specific blood flow based on the calculated motor current deviation value.