Blood pump system and method for controlling the speed of a blood pump drive unit

Abstract

The present invention relates to a blood pump system 10, particularly an intravascular blood pump, including a blood pump 12 having a pump housing 20 with a blood inlet 22 and a blood outlet 24 connected by a passage 26, an impeller 30 disposed within the pump housing 20, and a drive unit 28 configured to drive the impeller 30 at an actual speed so that a flow is generated between the blood inlet 22 and the blood outlet 24. The blood pump 12 further includes a sensor array 14 configured to output pressure data including an indicator of vascular pressure and / or an indicator of ventricular pressure, and a controller 16. The controller 16 is configured to adjust a speed profile that controls the actual speed of the drive unit 28 based on the pressure data output by the sensor array 18 so that the actual flow at the blood outlet 24 matches a target flow.

Description

[Technical Field]

[0001] The present invention relates to a blood pump system. In particular, the present invention relates to a blood pump system including a blood pump, in particular an intravascular blood pump, which is percutaneously inserted into a patient's blood vessel to assist blood flow in the patient's blood vessel. The blood pump may also be an intracardiac blood pump. The present invention further relates to a method for controlling the speed of a drive unit of the blood pump. [Background technology]

[0002] Various blood pumps, such as axial blood pumps, centrifugal (i.e., radial) blood pumps, or mixed-type blood pumps, are known in the prior art, in which blood flow is generated not only by radial but also by axial forces. Such blood pumps are introduced into a patient's heart to assist blood flow from the heart into blood vessels, such as the aorta or pulmonary artery. Blood pumps may also be introduced percutaneously through the vascular system during cardiac surgery, such as by catheterization. After the blood pump is installed, blood is pumped by the blood pump from the left ventricle into the aorta or from the right ventricle into the pulmonary artery to restore sufficient systemic blood flow. To this end, a blood pump typically comprises a pump housing having a blood inlet and a blood outlet connected by a passageway, a pump element in the form of an impeller disposed within the pump housing, and a drive unit configured to drive the impeller at an effective speed so that blood flow occurs between the blood inlet and the blood outlet.

[0003] During the cardiac cycle (i.e., during one heartbeat), the pressure conditions within each ventricle and blood vessel are not constant, but rather are modified by the relaxation and refilling of the heart during diastole, and the contraction and pumping of the heart during systole. Thus, the pressure conditions, and therefore the actual flow rate, are not continuous.

[0004] An intravascular blood pump placed in a patient's heart is operated at a given speed to generate continuous blood flow. Although the intravascular blood pump is intended as a ventricular assist device, the patient's heart is pumping (perhaps in a reduced or impaired state), and non-sustained blood flow is added to the continuous blood flow generated by the intravascular blood pump. Thus, the continuous planned target blood flow, e.g., 3.5 L / min or 4 L / min, may not be achieved. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object to provide a blood pump system and method of operating a blood pump that allows for a constant flow rate regardless of the pressure conditions within the patient's heart. [Means for solving the problem]

[0006] According to a first aspect, a blood pump system comprises a blood pump, in particular an intravascular blood pump, having a pump housing with a blood inlet and a blood outlet connected by a passageway. A pump element in the form of an impeller is arranged within the pump housing. The blood pump further comprises a drive unit configured to drive the impeller at an actual speed so that a flow occurs between the blood inlet and the blood outlet. The blood pump system further comprises a controller and a sensor array configured to output pressure data including an indicator of vascular pressure and / or an indicator of ventricular pressure. The controller is configured to adjust a speed profile that controls the actual speed of the drive unit based on the pressure data output by the sensor array, so that the actual flow at the blood outlet matches a target flow.

[0007] When the blood pump system is used as left ventricular assist, the vascular pressure is the aortic pressure and the ventricular pressure is the left ventricular pressure. Therefore, when used as right ventricular assist, the vascular pressure is the pulmonary artery pressure and / or central venous pressure and the ventricular pressure is the right ventricular pressure.

[0008] In the sense of the present invention, the actual flow rate is the total flow rate leaving the blood pump through the blood outlet. In other words, the actual flow rate is the pump flow rate, i.e., the flow rate passing through the pump housing. Therefore, the actual flow rate meets the set target flow rate during the entire heartbeat, regardless of the intracardiac pressure conditions during the entire heartbeat, because it is composed of the flow rate generated by the pumping elements and the flow rate possibly generated but likely impaired by the pumping action of the patient's heart through the blood pump. Therefore, the actual flow rate remains substantially constant at the planned target flow rate, since the actual speed of the drive unit is modified based on the speed profile. The controller calculates the intracardiac pressure conditions from the received pressure data, adjusts the speed profile for the complete heartbeat, and controls the actual speed to match the calculated pressure conditions. The intracardiac pressure conditions can be calculated from pressure data indicative of vascular or ventricular pressure. Of course, the pressure data preferably indicative of both vascular and ventricular pressure. The speed profile represents a curve or a set of speed values ​​that indicate the modification of the drive unit speed during the entire heartbeat or any other suitable time range. Therefore, during diastole, the actual speed of the drive unit is higher than during systole.

[0009] The blood pump of the blood pump system according to the present disclosure may correspond to the blood pumps described above. Thus, the blood pump may be an intravascular blood pump or an intracardiac blood pump.

[0010] The blood pump may include a sensor array in which the sensor is located, for example, in the pump housing. The sensor may be an optical sensor. The sensor array of the blood pump system may also be a sensor array independent of the blood pump.

[0011] Preferably, the sensor array is configured to output pressure data comprising at least one of a pressure value related to the pressure upstream or at the blood flow inlet as an indication for ventricular pressure, or a pressure value related to the pressure downstream or at the blood flow outlet as an indication for vascular pressure, said pressure values ​​may be measured by sensors arranged in close proximity to the blood flow inlet and / or the blood flow outlet.

[0012] The blood pump system may include a memory device. The speed profile may be stored in the memory device. A characteristic diagram relating pressure data to flow rates of the drive unit may be stored in the memory device. The controller may be configured to retrieve an ideal speed from the characteristic diagram based on the pressure data and the target flow rate. The controller may calculate a set speed for the speed profile based on the ideal speed, and may set the actual speed to the set speed for the speed profile.

[0013] The cause-and-effect diagram may be an individual cause-and-effect diagram for an individual blood pump. The cause-and-effect diagram may also be a cause-and-effect diagram for a reference series of blood pumps. Additionally or alternatively, the cause-and-effect diagram may also be a cause-and-effect diagram for a group of blood pumps within the reference series. In this regard, the individual blood pumps used may be classified as belonging to a certain group. Furthermore, the cause-and-effect diagram may be adjusted to take into account changes over the operating life of the blood pump caused, for example, by wear.

[0014] The characteristic diagram includes hydraulic flow curves for different speeds of the drive unit, showing the resulting flow rates based on the pressure data. Each hydraulic curve may show a specific speed of the drive unit that provides a specific flow rate for a P level of the drive unit, i.e., a pressure difference or pressure gradient across the blood pump, i.e., between the blood inlet and the blood outlet. The ideal speed may be derived either directly from the corresponding hydraulic curve or via extrapolation or interpolation. Preferably, the extrapolation and / or interpolation is performed by a controller.

[0015] The controller may be configured to consider a speed offset based on the actual speed of the drive unit in calculating the set speed. Because the blood pump is generating a specific blood flow when the pressure data is determined, the generated blood flow of the blood pump needs to be taken into account. Therefore, a specific speed offset is subtracted from the calculated set speed. The speed offset may be a constant value or a value associated with the actual speed, the ideal speed, or the set speed. Alternatively, the speed offset may be a value calculated from a characteristic diagram.

[0016] The controller may be configured to store the set speed time segments, and / or the ideal speed time segments, and / or the actual speed time segments, and / or the pressure data time segments in a memory device. Preferably, the controller is further configured to determine the impeller inertia based on an analysis of the actual speed and / or the set speed time segments, and / or the pressure data time segments, and to take the impeller inertia into account for the calculation of the set speed. Thus, when a speed profile is adjusted or initially generated, the impeller inertia may be taken into account to enable smoothing of the generated flow rate.

[0017] The controller may be configured to identify a repeating pattern in the pressure data. The repeating pattern may be a characteristic time course of ventricular pressure, i.e., left ventricular pressure or right ventricular pressure. If the blood pump is used as left ventricular assist, the repeating pattern may be represented, for example, by a minimum at the end of the relaxation phase of the left ventricle, indicating the start of diastole. The repeating pattern may also be, for example, a maximum pressure gradient during the contraction phase at the start of systole. The repeating pattern may also be, for example, the start point of the contraction phase of the left ventricle, the so-called end-diastolic pressure point. The repeating pattern is used to define the start and end of one heartbeat.

[0018] The controller may be further configured to iteratively adjust the velocity profile based on optimizing a mathematical cost function. Based on the pressure data, the controller calculates the statistical variance or variability between the actual and set values, i.e., the control error. For example, the controller may calculate the variability or average difference between the target flow rate and the actual generated beat-to-beat flow rate. The magnitude of the error, such as the standard deviation, standard error, or root-mean-square error, may be calculated and compared with a predetermined threshold or tolerance interval. As soon as the magnitude of the error exceeds the threshold or tolerance interval, velocity profile adjustment is again performed. In other words, if the patient's heart rate is perfectly constant and the pressure conditions do not change, little velocity profile adjustment will occur.

[0019] The controller may also be configured to adjust the velocity profile at a predetermined frequency, preferably in a repeating pattern. For example, the velocity profile may be adjusted at a predetermined time interval, such as every 5 seconds. The velocity profile may also be adjusted, for example, every 5 heartbeats, with the start and end of the heartbeats determined by the repeating pattern.

[0020] The controller may be configured to apply a signal filter, for example a low pass filter, so that meaningless and erroneous pressure data can be filtered out. Generally, this avoids unnecessary adjustments to the velocity profile.

[0021] According to a second aspect, there is provided a method for controlling the speed of a drive unit of a blood pump of a blood pump system. The blood pump of the blood pump system according to the present disclosure may correspond to the blood pump described above. Accordingly, the blood pump may be an intravascular blood pump or an intracardiac blood pump. The blood pump comprises a pump housing having a blood inlet and a blood outlet connected by a passageway, and a pump element in the form of an impeller disposed within the pump housing. The blood pump further comprises a drive unit configured to drive the impeller at an actual speed, thereby generating a flow rate between the blood inlet and the blood outlet. The method includes receiving pressure data including an indicator of vascular pressure and / or an indicator of ventricular pressure, and adjusting a speed profile that controls the actual speed of the drive unit based on the received pressure data, such that the actual flow rate at the blood outlet corresponds to a target flow rate.

[0022] When the blood pump system is used as left ventricular assist, the vascular pressure is the aortic pressure and the ventricular pressure is the left ventricular pressure. Therefore, when used as right ventricular assist, the vascular pressure is the pulmonary artery pressure and / or central venous pressure and the ventricular pressure is the right ventricular pressure.

[0023] The step of receiving pressure data may further include receiving at least one of a pressure related to the pressure upstream of or at the blood flow inlet as an indicator of ventricular pressure, or a pressure related to the pressure downstream of or at the blood flow outlet as an indicator of vascular pressure.

[0024] The step of adjusting the velocity profile may further include retrieving an ideal velocity based on the pressure data from a characteristic diagram relating the pressure data to the target flow rate, calculating a set velocity for the velocity profile based on the ideal velocity, and setting the actual velocity to the set velocity for the velocity profile.

[0025] The step of calculating the set speed of the speed profile may further include considering a speed offset based on the actual speed.

[0026] The method may further include storing time segments of set speed, and / or time segments of ideal speed, and / or time segments of actual speed, and / or time segments of pressure data.

[0027] The step of calculating the set speed of the speed profile may further include determining an inertia of the impeller based on an analysis of the actual speed, and / or the set speed, and / or the pressure data for a time segment, and taking the inertia of the impeller into account for the calculation of the set speed.

[0028] The method may further include identifying repetitive patterns in the pressure data.

[0029] The method may further include adjusting the velocity profile based on optimizing a mathematical cost function and / or adjusting the velocity profile at a predetermined frequency, preferably at a predetermined frequency in a repeating pattern.

[0030] The method according to the present disclosure has corresponding features and advantages over known methods for controlling the speed of a drive unit of a blood pump in a blood pump system, such as the blood pump system according to the disclosures mentioned above.

[0031] The above summary, as well as the following detailed description of the preferred embodiments, will be better understood when read in conjunction with the accompanying drawings. For purposes of explaining the present disclosure, reference is made to the drawings. However, the scope of the present disclosure is not limited to the specific embodiments disclosed in the drawings. [Brief explanation of the drawings]

[0032] [Figure 1] 1 shows a schematic diagram of a blood pump system according to the present disclosure. [Figure 2] 2 is a side view of a pump housing of the blood pump of the blood pump system of FIG. 1. [Figure 3] 1 is a graph showing left ventricular pressure, aortic pressure, actual speed of the drive unit of the blood pump, and set speed for one heartbeat. [Figure 4] FIG. 1 is a characteristic diagram for a blood pump relating pressure data to flow rate. [Figure 5] 1 is a graph showing left ventricular pressure and aortic pressure for six consecutive heartbeats. [Figure 6] 6 is a graph showing the actual speed and set speed of the drive unit of the blood pump for the heart rate shown in FIG. 5. [Figure 7] 1 is a graph showing a target flow rate and an actual flow rate. DETAILED DESCRIPTION OF THE INVENTION

[0033] 1 is a schematic diagram of a blood pump system 10. The blood pump system 10 includes a blood pump 12, a sensor array 14, a controller 16, and a storage device 18. The blood pump 12, the sensor array 14, and the storage device 18 are connected to the controller 16 by suitable devices, such as cables. Of course, wireless connections are also possible. Furthermore, the storage device 18 may be an integral part of the controller 16.

[0034] Blood pump 12 may be an intravascular blood pump that belongs to applicant's Impella® product family. Blood pump 12 includes a pump housing 20 having a blood inlet 22 and a blood outlet 24. Blood inlet 22 is connected to blood outlet 24 by a passageway 26. Here, pump housing 20 includes a plurality of blood outlets 24 evenly distributed around the circumference of blood pump housing 20 (see also FIG. 2).

[0035] A drive unit 28 is disposed within the pump housing 20. The drive unit 28 is configured to drive a pump element in the form of an impeller 30 disposed within the pump housing 20 at a particular speed, as will be described in more detail below. In the illustrated embodiment, the drive unit 28 is disposed within the pump housing 20, although it is also possible for the drive unit 28 to be external and connected to the impeller 30 by a suitable device.

[0036] Rotation of the impeller 30 may be caused by a direct connection between the drive unit 28 and the impeller 30, or by an indirect connection such as a magnetic coupling. As the impeller 30 rotates, blood flow is generated from the blood inlet 22 along the passageway 26 to the blood outlet 24. In particular, when placed within a patient's heart, the blood inlet 22 is positioned so that blood from the ventricles of the patient's heart can be drawn into the blood pump 12 and exit the blood pump 12 through the blood outlet 24 into a blood vessel. In addition to the blood flow generated by the blood pump 12 between the blood inlet 22 and the blood outlet 24, blood flow generated by the pumping action of the patient's heart may be added, and the pumping action depends on the condition of the patient's heart such that the actual blood flow at the blood outlet 24 does not necessarily correspond solely to the blood flow generated by the blood pump 12. Rather, the actual flow rate is the total flow rate exiting the blood pump 12 through the blood outlet 24.

[0037] In the embodiment shown in FIG. 2 , the sensor array 14 includes two sensors 32, 34 disposed on the outer periphery of the pump housing 20. The two sensors 32, 34 may be optical pressure sensors. One of the sensors 32, 34 is located in close proximity to the blood inlet 22, so that the detected pressure provides an indication of ventricular pressure, particularly left ventricular pressure (LVP), when the blood pump 12 is used as left ventricular assist. The other of the two sensors 32, 34 is located in close proximity to the blood outlet 24, so that the detected pressure provides an indication of vascular pressure, particularly aortic pressure (AOP), when the blood pump 12 is used as left ventricular assist. Thus, the sensor array 14 is configured to output pressure data including an indication of aortic pressure (AOP) and left ventricular pressure (LVP). The blood pump 12 may also be used as right ventricular assist. In this case, the right ventricular pressure and pulmonary artery pressure are indicated by the pressures detected by the two sensors 32, 34. However, the following description will be given using the blood pump 12 as left ventricular assist.

[0038] The sensor array 14 may be an external sensor array that outputs pressure data including indices for aortic pressure AOP and left ventricular pressure LVP. For example, the sensor array may include sensors introduced by catheter into the aorta to measure aortic pressure AOP or into the left ventricle to measure left ventricular pressure LVP. The pressure data output by the sensor array 14 signals the controller 16 to adjust a velocity profile that controls the actual velocity AS of the drive unit 28.

[0039] In the exemplary embodiment, the pressure data is described as including the aortic pressure AOP and the left ventricular pressure LVP, however, the method described below for controlling the speed of the drive unit 28 of the blood pump 12 requires only one of the aortic pressure AOP and the left ventricular pressure LVP to be determined.

[0040] The drive unit 28 drives the impeller 30 at an actual speed AS defined in a speed profile. The speed profile represents a curve or set of speed values ​​that indicate the speed modification of the drive unit 28 over an entire heartbeat or any other suitable time range. The speed profile may be stored in the memory device 18 and may be adjusted and modified by the controller 16, which may be described in more detail below.

[0041] Initially, the speed profile includes a default speed SS that drives the drive unit 28, and thus the impeller 30, at a given speed, e.g., 24,000 rpm. However, the controller 16 may adjust the speed profile so that the actual flow rate AF at the blood outlet 24 matches a predetermined target flow rate TF, e.g., 4 L / min, regardless of the pumping action of the patient's heart. Of course, it is impossible to exactly match the actual flow rate AF to the target flow rate TF. Therefore, a certain deviation between the actual flow rate AF and the target flow rate TF is acceptable. Therefore, the term "match" as used herein to describe the relationship between the actual flow rate AF and the target flow rate TF should be understood broadly.

[0042] After installation of the blood pump 12, the drive unit 28 is operated by the controller 16 to drive the impeller 30 at the set speed SS stored in the speed profile. This initial operation is shown for one heartbeat in FIG. 3, where the set speed SS of the 24,000 rpm speed profile is shown as a dashed line on the secondary vertical axis. The actual speed AS of the drive unit 28, and therefore the impeller 30, is shown as a solid black line. The initial peak as the speed decreases to approximately 20,000 rpm is caused by defocusing of the impeller 30 due to, for example, inertia. Thereafter, the actual speed AS substantially matches the set speed SS.

[0043] During this initial phase, pressure data is recorded by the controller 16 and stored in the memory device 18. In FIG. 3, for one heartbeat, the left ventricular pressure LVP is shown as a thick gray solid line, and the aortic pressure AOP is shown as a thin black solid line. The controller 16 then identifies a repeating pattern in the pressure data, i.e., the repeating pattern of the left ventricular pressure LVP. The repeating pattern is a characteristic time course for each heartbeat and is used to distinguish between two heartbeats. The repeating pattern may be represented, for example, by a minimum value of the left ventricular pressure LVP at the end of the relaxation phase, which corresponds to the beginning of diastole (near time 110 in FIG. 3). In the illustrated embodiment, the repeating pattern is set to be the maximum pressure gradient during the contraction phase at the beginning of systole (near time 0 in FIG. 3). The repeating pattern may be, for example, the start of the left ventricular contraction phase, the so-called end-diastolic pressure point.

[0044] Controller 16 then retrieves the ideal speed from a cause-and-effect diagram CD stored in memory device 18. An example of a cause-and-effect diagram is shown in FIG. 4. The cause-and-effect diagram includes hydraulic flow curves (P1-P9) for various speeds of blood pump 12 that relate the pressure difference or pressure gradient across blood pump 12 to the delivered blood flow. For example, hydraulic flow curve P5 represents a speed of 24,000 rpm. The hydraulic flow curves increase and decrease in 2,000 rpm increments. Thus, hydraulic flow curve P6 represents a speed of 26,000 rpm, and hydraulic flow curve P4 represents a speed of 22,000 rpm. Hydraulic flow curves P1-P9 may be individual flow curves for a particular blood pump 12, or may be hydraulic flow curves for an entire reference series of blood pumps 12 or for a group of blood pumps within a reference series.

[0045] The pressure difference across the blood pump 12 corresponds to the pressure gradient between the blood inlet 22 and the blood outlet 24, and thus to the pressure gradient between the left ventricular pressure LVP and the aortic pressure AOP. The controller 16 derives an ideal speed for reaching a planned target flow rate TF, e.g., 4 L / min, for each time point within a heartbeat from the characteristic diagram CD. If hydraulic flow curves P1-P9 are not provided for a particular pressure difference, the controller 16 is configured to calculate the ideal speed based on interpolation and extrapolation between adjacent hydraulic flow curves P1-P9. The ideal speed at each time point within a heartbeat thus derived is then calculated by the controller 16 to derive a set speed SS of the drive unit 28 for each time point. In so doing, the controller 16 is configured to take into account a speed offset based on the actual speed AS of the drive unit 28 during this initial phase. In the exemplary embodiment described, the actual speed AS of the blood pump is set to 24,000 rpm during the initial phase. In other words, the actual speed AS of 24,000 rpm has a certain effect on the pressure gradient across the blood pump 12 and, therefore, on the ideal speed derived from the characteristic diagram. Therefore, a fixed speed offset is subtracted from the derived ideal speed. In an exemplary embodiment, the speed offset is set to 1,600 rpm. However, the speed offset need not be a fixed value and may depend on further variables, such as pressure data.

[0046] The controller 16 then stores the calculated set speed SS in the speed profile. When the next heartbeat begins in the repeating pattern, the actual speed AS of the drive unit 28 is set to correspond to the set speed SS in the speed profile. Essentially, the drive unit 28 is operated at various speeds during one heartbeat based on the modulated set speed SS so that the actual flow rate AF at the blood outlet 24 corresponds to a predetermined planned target flow rate TF, e.g., 4 L / min. For each repeating pattern for each successive heartbeat, the speed profile is replayed from the beginning.

[0047] The controller 16 is further configured to store various data, particularly pressure data, the set speed SS, and the time interval of the actual speed AS, in the memory device 18. From analyzing the data, the controller 16 may derive the inertia of the impeller 30 based on a comparison of when the actual speed AS is set to the set speed SS and when the planned actual speed AS is reached. Based on this, the controller 16 determines information about the inertia of the impeller 30 and adjusts the speed profile to account for the inertia of the impeller 30. The controller 16 may derive a fixed value to account for the inertia or may derive a function for the inertia based on the set speed SS.

[0048] The velocity profile is re-evaluated during normal operation of the blood pump 12 to take into account changed conditions. Therefore, the velocity profile adjustment method described above is repeated, for example, every five heartbeats. As a result, once the velocity profile is adjusted, conditions are assumed to remain constant for the next four consecutive heartbeats. A time segment showing the left ventricular pressure (LVP) (thick gray line) and aortic pressure (AOP) (thin solid black line) over six consecutive heartbeats is shown in FIG. 5 . As a result, the velocity profile is adjusted again during the last heartbeat shown in FIG. 5 , beginning around time 1190. The thin vertical lines indicate the repeating pattern that distinguishes one heartbeat from the next.

[0049] Additionally, time segments for the set speed SS (dotted line) and the actual speed AS (solid black line) are shown in FIG. 6. As shown, during the initial phase, which lasts until approximately time 250, the set speed SS corresponds rather to the initial speed of 24,000 rpm. Thereafter, the actual speed AS of the drive unit 28 tracks the set speed SS as it falls within the speed profile. However, during the first beat between approximately time 250 and time 480, the inertia of the impeller 30 has not yet been taken into account. During the next beat, the controller 16 has already taken the inertia of the impeller 30 into account, and the actual speed AS closely tracks the set speed SS.

[0050] In essence, this results in the actual flow rate AF at the blood outlet 24 approximately matching the planned target flow rate TF of 4 L / min (see FIG. 7 ). In FIG. 7 , the actual flow rate AF is shown by a solid black line, and the target flow rate TF is shown by a dashed line. Of course, a certain deviation between the actual flow rate AF and the target flow rate TF is acceptable as long as the deviation is within predetermined limits. Therefore, the adjustment of the velocity profile may additionally or alternatively be performed based on a minimized mathematical cost function. The controller 16 may be configured to calculate the statistical variation between the actual flow rate AF and the target flow rate TF. To that end, a suitable control error, such as a standard deviation, standard error, or root-mean-square error, may be calculated and compared with a predetermined threshold or tolerance interval. As soon as the magnitude of the error exceeds the threshold or tolerance interval, the adjustment of the velocity profile is performed. In addition, the controller 16 may also be configured to adjust the velocity profile at a given time interval, for example, for the first heartbeat after every 5 seconds. Additionally, the controller 16 may be configured to apply a signal filter to ensure that potentially erroneous measurements are discounted and do not result in unnecessary adjustments to the velocity profile. The signal filter may be, for example, a low-pass filter, a high-pass filter, a band-pass filter, and / or a moving average filter.

[0051] Exemplary Implementation As previously mentioned, the techniques described herein may be implemented in a variety of ways. In that regard, the foregoing disclosure is intended to include, but is not limited to, the systems, methods, and combinations and subcombinations thereof described in the following exemplary implementations. Preferred embodiments are described in the following paragraphs: A1 A blood pump system comprising: a blood pump, in particular an intravascular blood pump, having a pump housing with a blood inlet and a blood outlet connected by a passage; a pump element disposed within the pump housing; a drive unit configured to drive the pump element at an actual speed so that a flow rate is generated between the blood inlet and the blood outlet; a sensor array configured to output pressure data including an indicator for vascular pressure and / or an indicator for ventricular pressure; and a controller, the controller being further configured to adjust a speed profile that controls the actual speed of the drive unit based on the pressure data output by the sensor array so that the actual flow rate at the blood outlet matches a target flow rate. A2. The blood pump system according to item A1, wherein the pump element is an impeller. A3. A blood pump system as described in item A1 or A2, wherein the sensor array is configured to output pressure data including at least one of a pressure value related to the pressure upstream of or at the blood flow inlet as an indicator of left ventricular pressure, or a pressure value related to the pressure downstream of or at the blood flow outlet as an indicator of aortic pressure. A4: The blood pump system according to any one of items A1 to A3, wherein the blood pump includes a sensor array. A5. The blood pump system according to item A4, wherein the sensor array comprises two sensors. A6. The blood pump system according to item A5, wherein one of the sensors is disposed near the blood flow inlet and / or another of the sensors is disposed near the blood flow outlet. A7. The blood pump system according to item A5 or A6, wherein the sensor is an optical sensor, in particular an optical pressure sensor. A8: The blood pump system according to any one of items A1 to A3, wherein the sensor array is separate from the blood pump. A9 The blood pump system according to any one of items A1 to A8, further comprising a storage device. A10. The blood pump system of item A9, wherein the characteristic diagram relating pressure data to flow rate of the drive unit is stored in the memory device. A11. The blood pump system of claim A10, wherein the controller is configured to retrieve the ideal speed from the characteristic diagram based on the pressure data and the target flow rate. A12. The blood pump system of item A11, wherein the controller is further configured to calculate a set speed of the speed profile based on the ideal speed and set the actual speed to the set speed of the speed profile. A13. The blood pump system of item A12, wherein the controller is further configured to consider a speed offset based on the actual speed for calculating the set speed. A14. The blood pump system of claim A13, wherein the controller is further configured to determine the ideal speed based on interpolation and extrapolation. A15: The blood pump system according to any one of items A10 to A14, wherein the cause-and-effect diagram is an individual cause-and-effect diagram for a specific blood pump. A16. The blood pump system according to any one of items A10 to A14, wherein the cause-and-effect diagram is a cause-and-effect diagram for a reference series of blood pumps or for a group of blood pumps within a reference series of blood pumps. A17. The blood pump system according to any one of items A10 to A16, wherein the characteristic diagram includes a plurality of hydraulic flow curves for different speeds of the drive unit. A18. A blood pump system according to any one of items A9 to A17, wherein the controller is further configured to store time segments of the set speed, and / or time segments of the ideal speed, and / or time segments of the actual speed, and / or time segments of the pressure data in a memory device. A19. The blood pump system of item A18, wherein the controller is further configured to determine the inertia of the pump element based on analysis of the time interval of the actual speed, and / or the set speed, and / or the pressure data, and to take the inertia of the pump element into account for calculation of the set speed. A20. The blood pump system of any one of items A1-A19, wherein the controller is further configured to identify repetitive patterns in the pressure data. A21 The blood pump system of item A20, wherein the repetitive pattern is a pattern in the pressure signal indicative of ventricular pressure. A22. A blood pump system according to item A20 or A21, wherein the repeating pattern is a minimum at the end of the relaxation phase of the ventricle, or the repeating pattern is a maximum pressure gradient during the contraction phase at the beginning of systole, or the repeating pattern may be the start point of the contraction phase of the left ventricle, in particular the end-diastolic pressure point. A23. The blood pump system of any one of items A1 to A22, wherein the controller is further configured to repeat the adjustment of the speed profile based on optimization of a mathematical cost function and / or to adjust the speed profile at a predetermined frequency, preferably to adjust the speed profile at a predetermined frequency in a repeating pattern. A24. The blood pump system of item A24, wherein the controller is configured to calculate a statistical variance or variability between the actual value and the set value, preferably between the actual flow rate and the target flow rate. A25. The blood pump system of any one of items A1 to A24, wherein the controller is further configured to apply a signal filter. A26: The blood pump system according to any one of items A1 to A25, wherein the vascular pressure is an aortic pressure, and / or the ventricular pressure is a left ventricular pressure. A27 The blood pump system according to item A26, wherein the blood pump system is a left ventricular assist blood pump system. A28. The blood pump system according to any one of items A1 to A25, wherein the vascular pressure is pulmonary artery pressure and / or the vascular pressure is central venous pressure, and the ventricular pressure is right ventricular pressure. A29 The blood pump system according to item A28, wherein the blood pump system is a right ventricular assist blood pump system. B1 A method for controlling the speed of a drive unit of a blood pump, in particular an intravascular blood pump, the blood pump comprising a pump housing having a blood inlet and a blood outlet connected by a passage, a pump element disposed within the pump housing, and a drive unit configured to drive the pump element at an actual speed so as to generate a flow between the blood inlet and the blood outlet, the method comprising the steps of receiving pressure data comprising an indicator for vascular pressure and / or an indicator for ventricular pressure, and adjusting a speed profile that controls the actual speed of the drive unit based on the received pressure data so that the actual flow at the blood outlet corresponds to a target flow. B2 The method according to item B1, wherein the pump element is an impeller. B3. The method of any one of items B1 and B2, wherein the step of receiving pressure data further comprises receiving at least one of a pressure related to the pressure upstream of or at the blood flow inlet as an indicator of ventricular pressure, or a pressure related to the pressure downstream of or at the blood flow outlet as an indicator of vascular pressure. B4. The method according to any one of items B1 to B3, wherein the step of adjusting the velocity profile further comprises retrieving an ideal velocity based on the pressure data from a characteristic diagram relating the pressure data to the target flow rate. B5. The method of claim B4, wherein the step of adjusting the speed profile further includes calculating a set speed for the speed profile based on an ideal speed. B6. The method of claim B5, wherein the step of adjusting the velocity profile further includes determining an ideal velocity based on interpolation and extrapolation. B7 The method according to any one of items B4 to B6, wherein the cause-and-effect diagram is an individual cause-and-effect diagram for a particular blood pump. B8. The method according to any one of items B4 to B6, wherein the cause-and-effect diagram is a cause-and-effect diagram for a reference series of blood pumps or for a group of blood pumps within a reference series of blood pumps. B9 The method of any one of items B4 to B8, wherein the characteristic diagram includes a plurality of hydraulic flow curves for different speeds of the drive unit. B10 The method according to any one of items B5 to B9, wherein the step of adjusting the speed profile further includes setting the actual speed to a set speed of the speed profile. B11 The method according to any one of items B5 to B10, wherein the step of calculating the set speed further includes considering a speed offset based on the actual speed. B12 The method of any one of clauses B1 to B11, wherein the method further comprises storing time segments of set speed, and / or time segments of ideal speed, and / or time segments of actual speed, and / or time segments of pressure data. B13. The method of claim B12, wherein the step of calculating the set speed further includes determining the inertia of the pump element based on analysis of time segments of the actual speed and / or pressure data. B14. The method of claim B13, wherein the step of calculating the set speed further includes accounting for inertia of the pump element for the calculation of the set speed. B15 The method of any one of paragraphs B1-B14, wherein the method further includes identifying repeating patterns in the pressure data. B16. The method of claim B15, wherein identifying a repetitive pattern includes identifying a repetitive pattern in the pressure signal indicative of ventricular pressure. B17 The method according to item B15 or B16, wherein the step of identifying the recurring pattern comprises identifying a minimum at the end of the relaxation phase of the left ventricle or identifying a maximum pressure gradient during the contraction phase at the beginning of systole, and the recurring pattern may be the start point of the contraction phase of the left ventricle, in particular the end-diastolic pressure point. B18 The method according to any one of items B1 to B17, wherein the method further comprises adjusting the speed profile based on optimizing a mathematical cost function and / or adjusting the speed profile at a predetermined frequency, preferably at a predetermined frequency in a repeating pattern. B19 The method according to item B18, wherein the step of adjusting the speed profile based on optimizing the mathematical cost function further comprises calculating the statistical variance or variability between the actual value and the set value, preferably between the actual flow rate and the target flow rate. B20 The method of any one of clauses B1 to B19, wherein the method further comprises applying a signal filter to the pressure data, and / or the velocity profile, and / or the set velocity. B21 The method according to any one of items B1 to B20, wherein the vascular pressure is an aortic pressure and / or the ventricular pressure is a left ventricular pressure. B22 The method according to item B21, wherein the blood pump is a left ventricular assist blood pump. B23 The method according to any one of items B1 to B20, wherein the vascular pressure is pulmonary artery pressure and / or the vascular pressure is central venous pressure and the ventricular pressure is right ventricular pressure. B24 The method according to item B23, wherein the blood pump is a right ventricular assist blood pump.

[0052] As used herein, the terms "approximately," "about," "substantially," "in fact," and similar terms are intended to have a broad meaning consistent with common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of ordinary skill in the art who review this disclosure that these terms are intended to be descriptive of the particular features described without limiting the scope of the particular features described to the exact numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or insignificant modifications or variations of the subject matter described are considered to be within the scope of the disclosure. [Explanation of symbols]

[0053] 10 Blood Pump System 12 Blood Pump 14 Sensor Array 16 Controller 18 Storage device 20 Pump housing 22 Blood flow inlet 24 Blood flow outlet 26 Passage 28 Drive Unit 30 impeller 32 sensors 34 Sensors AF Actual flow rate AOP aortic pressure AS Actual speed CD Fishbone Diagram LVP left ventricular pressure P1~P9 Liquid pressure flow curve SS setting speed TF target flow rate

Claims

1. A blood pump (12), in particular an intravascular blood pump, comprising: a pump housing (20) having a blood inlet (22) and a blood outlet (24) connected by a passage (26); an impeller (30) disposed within the pump housing (20); and a drive unit (28) configured to drive the impeller (30) at an actual speed (AS) so that a flow rate is generated between the blood inlet (22) and the blood outlet (24). a sensor array (14) configured to output pressure data including an index for vascular pressure (AOP) and / or an index for ventricular pressure (LVP); A controller (16); Equipped with The controller (16) is further configured to adjust a speed profile that controls the actual speed (AS) of the drive unit (28) based on the pressure data output by the sensor array (18) so that the actual flow rate (AF) at the blood outlet (24) matches the target flow rate (TF). A blood pump system (10).

2. the sensor array (14) is configured to output pressure data including at least one of a pressure value related to pressure upstream or at the blood inlet (22) as an indicator of the ventricular pressure (LVP), or a pressure value related to pressure downstream or at the blood outlet (24) as an indicator of the vascular pressure (AOP). The blood pump system (10) of claim 1.

3. The blood pump system (10) further comprises a memory device (18); a characteristic diagram (CD) relating the pressure data to the flow rate of the drive unit (28) is stored in the storage device (18); The controller (16) is configured to read an ideal speed from the characteristic diagram (CD) based on the pressure data and the target flow rate (TF), calculate a set speed (SS) of the speed profile based on the ideal speed, and set the actual speed (AS) to the set speed (SS) of the speed profile. A blood pump system (10) according to claim 1 or 2.

4. The controller (16) is further configured to take into account a speed offset based on the actual speed (AS) for calculating the set speed (SS). The blood pump system (10) of claim 3.

5. The controller (16) is further configured to store time segments of the set speed (SS), and / or time segments of the ideal speed, and / or time segments of the actual speed (AS), and / or time segments of the pressure data in the storage device (18), and preferably the controller (16) is further configured to determine an inertia of the impeller (30) based on an analysis of the time segments of the actual speed (AS), and / or the set speed (SS), and / or the time segments of the pressure data, and take the inertia of the impeller (30) into account for calculation of the set speed (SS). A blood pump system (10) according to claim 3 or 4.

6. The controller (16) is further configured to identify repetitive patterns within the pressure data. A blood pump system (10) according to any one of claims 1 to 5.

7. the controller (16) is further configured to repeat the adjustment of the velocity profile based on optimization of a mathematical cost function and / or to adjust the velocity profile at a predetermined frequency, preferably at a predetermined frequency in the repeating pattern. A blood pump system (10) according to any one of claims 1 to 6.

8. A method for controlling the speed of a drive unit (28) of a blood pump (12), in particular an intravascular blood pump, comprising: a pump housing (20) having a blood flow inlet (22) and a blood flow outlet (24) connected by a passageway (26); an impeller (30) disposed within the pump housing (20); a drive unit (28) configured to drive the impeller (30) at an actual speed (AS) such that a flow rate is generated between the blood flow inlet (22) and the blood flow outlet (24); Equipped with The method comprises: - receiving pressure data comprising an index for vascular pressure (AOP) and / or an index for ventricular pressure (LVP); - adjusting a speed profile controlling the actual speed (AS) of the drive unit (28) based on the received pressure data so that the actual flow rate (AF) at the blood outlet (24) corresponds to a target flow rate (TF); A method comprising:

9. The step of receiving pressure data comprises: receiving at least one of a pressure upstream of or related to the pressure at the blood inlet (22) as an indicator for the ventricular pressure (LVP), or a pressure downstream of or related to the pressure at the blood inlet (24) as an indicator for the vascular pressure (AOP); The method of claim 8 further comprising:

10. The step of adjusting the velocity profile comprises: - retrieving an ideal velocity based on said pressure data from a characteristic diagram (CD) relating said pressure data to said target flow rate (TF); - calculating a set speed (SS) of said speed profile based on said ideal speed; - setting said actual speed (AS) to said set speed (SS) of said speed profile; 10. The method of claim 8 or 9, further comprising:

11. The step of calculating the set speed (SS) comprises: - taking into account a speed offset based on the actual speed (AS) The method of claim 10 further comprising:

12. The method comprises: - storing time segments of the set speed (SS), and / or time segments of the ideal speed, and / or time segments of the actual speed (AS), and / or time segments of the pressure data; The method of any one of claims 8 to 11, further comprising:

13. The step of calculating the set speed (SS) comprises: - determining the inertia of the impeller (30) based on an analysis of the time segments of the actual speed (AS) and / or the pressure data; - taking into account the inertia of the impeller (30) for the calculation of the set speed (SS); The method of claim 12 further comprising:

14. The method comprises: - identifying recurring patterns within said pressure data; The method of any one of claims 8 to 13, further comprising:

15. The method comprises: adjusting the velocity profile based on the optimization of a mathematical cost function, and / or - adjusting said speed profile at a predetermined frequency, preferably at a predetermined frequency of said repeating pattern; The method of any one of claims 8 to 14, further comprising:

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