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

Abstract

The invention relates to a blood pump system (10) comprising a blood pump (12), in particular an intravascular blood pump, having a pump housing (20) with a blood flow inlet (22) and a blood flow outlet (24) connected by a channel (26), an impeller (30) arranged in the pump housing (20), and a drive unit (28) arranged in the pump housing (20), a drive unit (28) is configured to drive the impeller (30) at an actual speed so as to create a flow between the blood flow inlet (22) and the blood flow outlet (24). The blood pump (12) further comprises a sensor device (14) and a controller (16), the sensor device (14) being configured to output pressure data comprising an indication of vascular pressure and / or an indication of ventricular pressure. The controller (16) is configured to adjust a speed profile controlling an actual speed of the drive unit (28) in dependence on the pressure data output by the sensor device (14) such that an actual flow at the blood flow outlet (24) corresponds to a target flow.

Description

Technical Field

[0001] The present invention relates to a blood pump system. More particularly, the present invention relates to a blood pump system including a blood pump, in particular an intravascular blood pump for percutaneous insertion into a patient's blood vessel to support blood flow in the patient's blood vessel, and the blood pump may also be an intracardiac blood pump. The present invention also relates to a method for controlling the speed of a drive unit for driving the blood pump. Background Art

[0002] A variety of blood pumps are known in the prior art, such as axial blood pumps, centrifugal (i.e., radial) blood pumps, or hybrid blood pumps, in which blood flow is induced by axial forces as well as radial forces. Such blood pumps can be introduced into a patient's heart to support blood flow from the heart into blood vessels, such as the aorta or pulmonary artery. The blood pump can be percutaneously introduced through the vascular system during cardiac surgery, for example, introduced by a catheterization procedure. After the blood pump is placed, the blood pump can eject blood from the left ventricle into the aorta or from the right ventricle into the pulmonary artery to restore sufficient systemic blood flow. Therefore, the blood pump generally includes a pump housing having a blood flow inlet and a blood flow outlet connected by a channel, a pump assembly disposed in the pump housing in the form of an impeller, and a drive unit configured to drive the impeller at an actual speed such that blood flow is generated between the blood flow inlet and the blood flow outlet.

[0003] During the cardiac cycle (i.e., during one heartbeat), the pressure conditions in the individual ventricles and blood vessels are not constant, but change during diastole, systole, and the pumping action during systole due to cardiac diastole and blood replenishment. Therefore, the pressure conditions and the actual flow rate are not continuous.

[0004] The intravascular blood pump placed in a patient's heart operates at a given speed and generates continuous blood flow. Although the intravascular blood pump is used as a ventricular assist device, the patient's heart is performing (possibly reduced or impaired) pumping action, which adds non-continuous blood flow to the continuous blood flow generated by the intravascular blood pump. Therefore, it may not be possible to achieve a continuous expected target flow rate, such as 3.5 liters per minute or 4 liters per minute.

[0005] Therefore, an object of the present invention is to provide a blood pump system and a method for operating a blood pump that allow a constant flow rate independent of the pressure conditions in a patient's heart. Summary of the Invention

[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 flow inlet and a blood flow outlet connected by a channel. A pump assembly in the form of an impeller is arranged in the pump housing. The blood pump further comprises a drive unit that drives the impeller at an actual speed such that a flow is generated between the blood flow inlet and the blood flow outlet. The blood pump system further comprises a controller and a sensor device that is configured to output pressure data comprising an indication of vascular pressure and / or an indication 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 device such that an actual flow rate at the blood flow outlet corresponds to a target flow rate.

[0007] In the case where the blood pump system is used to support the left ventricle, the vascular pressure is the aortic pressure and the ventricular pressure is the left ventricular pressure. Correspondingly, if it is used to support the right ventricle, the vascular pressure is the pulmonary artery pressure and / or the central venous pressure, and the ventricular pressure is the right ventricular pressure.

[0008] In the context of the present invention, the actual flow rate is the total flow rate leaving the blood pump via the blood flow outlet. In other words, the actual flow rate is the pump flow rate, i.e., the flow rate through the pump housing. Thus, the actual flow rate meets the set target flow rate during one complete heartbeat, regardless of the pressure conditions within the heart during the complete heartbeat, since the actual flow rate consists of the flow rate generated by the pump assembly and the possibly impaired flow rate generated by the patient's heart via the pumping action of the blood pump. Therefore, when the actual speed of the drive unit is modified according to the speed profile, the actual flow rate will substantially remain constant at the expected target flow rate. The controller calculates the pressure situation in the heart based on the received pressure data, adjusts the speed profile for the complete heartbeat, and controls the actual speed to the calculated pressure situation. The pressure situation in the heart can be calculated based on the pressure data giving an indication of vascular pressure or ventricular pressure. Of course, it is preferred that the pressure data gives an indication of both vascular pressure and ventricular pressure. The speed profile depicts a set of speed modification curves or speed values of the drive unit during a complete heartbeat or any other suitable time period. Thus, during diastole, the actual speed of the drive unit will be higher than during systole.

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

[0010] The blood pump may comprise a sensor device, where the sensor is located, for example, at the pump housing. The sensor can be an optical sensor. The sensor device of the blood pump system can also be a sensor device independent of the blood pump.

[0011] Preferably, the sensor device is configured to output pressure data including at least one of a pressure value indicative of ventricular pressure related to the pressure upstream of or at the blood flow inlet or a pressure value indicative of vascular pressure related to the pressure downstream of or at the blood flow outlet.

[0012] The blood pump system may include a storage device in which the speed curve may be stored. A characteristic map associating the pressure data with the flow rate of the drive unit may be stored in the storage device. The controller may be configured to read an ideal speed from the characteristic map based on the pressure data and the target flow rate, calculate a set speed of the speed curve based on the ideal speed, and set the actual speed to the set speed of the speed curve.

[0013] The characteristic map may be an individual characteristic map of an individual blood pump. This characteristic map may also be a characteristic map of a type series of blood pumps. Additionally or alternatively, the characteristic map may further be a characteristic map of a group of blood pumps within a type series. From this perspective, the individual blood pump used may be classified as belonging to a certain group. Furthermore, the characteristic map may be adapted to take into account changes caused, for example, by wear during the operation time of the blood pump.

[0014] The characteristic map includes hydraulic flow curves of the drive unit at different speeds, representing the resulting flow rate based on the pressure data. Each hydraulic curve may represent the P level of the drive unit, i.e., the specific speed at which the drive unit delivers a certain flow rate for a pressure difference or pressure gradient across the blood pump (i.e., between the blood flow inlet and the blood flow outlet). The ideal speed may be directly derived from the corresponding hydraulic curve or may be derived by extrapolation or interpolation. Preferably, the extrapolation and / or interpolation is performed by the controller.

[0015] The controller may be configured to calculate the set speed taking into account a speed offset based on the actual speed of the drive unit. Since the blood pump is generating a certain blood flow when determining the pressure data, the blood flow generated by the blood pump needs to be considered. Therefore, a certain speed offset is deducted from the calculated set speed. The speed offset may be a constant value, a value related to the actual speed, the ideal speed, or the set speed respectively. Alternatively, the speed offset may be a value calculated based on the characteristic map.

[0016] The controller may be configured to store the time period of the set speed and / or the time period of the ideal speed and / or the time period of the actual speed and / or the time period of the pressure data in the storage device. Preferably, the controller is further configured to determine the inertia of the impeller based on the analysis of the time period of the actual speed and / or the set speed and / or the time period of the pressure data, and calculate the set speed taking into account the inertia of the impeller. Thus, when adjusting or initially generating the speed curve, the inertia of the impeller can be considered to smooth the generated flow rate.

[0017] The controller can be set to recognize repeating patterns in the pressure data. The repeating pattern can be characteristic time points of the ventricular pressure (i.e., left ventricular pressure or right ventricular pressure). In the case where the blood pump is used to support the left ventricle, the repeating pattern can be depicted, for example, by the minimum value at the end of the diastolic phase of the left ventricle, which depicts the start of diastole. The repeating pattern can also be, for example, the maximum pressure gradient during the systolic phase at the start of cardiac contraction. The repeating pattern can also be, for example, the starting point of the left ventricular systolic phase, i.e., the so-called end-diastolic pressure point. The repeating pattern is used to define the start and end of one heartbeat.

[0018] The controller can also be set to repeatedly adjust the speed curve according to an optimized mathematical cost function. Based on the pressure data, the controller calculates the statistical deviation or variability between the actual value and the set value, i.e., the control error. For example, the controller can calculate the variability or average difference between the target flow rate and the flow rate actually generated per heartbeat. Error metrics such as standard deviation, standard error, or root mean square error can be calculated and compared with a predefined threshold or acceptance interval. Once the error metric exceeds the threshold or acceptance interval, the speed curve is adjusted repeatedly. In other words, if the patient's heartbeat is absolutely constant and the pressure conditions do not change, there will be little adjustment of the speed curve.

[0019] The controller can also be set to adjust the speed curve at a predefined frequency, preferably at the predefined frequency of the repeating pattern. For example, the speed curve can be adjusted at predefined time intervals (e.g., every 5 seconds). It can also be, for example, adjusted every five heartbeats, where the start and end of the heartbeat are defined by the repeating pattern.

[0020] The controller can be set to apply a signal filter, such as a low-pass filter. Thus, insignificant erroneous pressure data can be filtered out. Overall, this can avoid unnecessary adjustment of the speed curve.

[0021] According to a second aspect of the present invention, 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 invention can correspond to the aforementioned blood pump. Thus, the blood pump can be an intravascular blood pump or an intracardiac blood pump. The blood pump includes a pump housing having a blood flow inlet and a blood flow outlet connected by a channel, and a pump assembly in the form of an impeller disposed in the pump housing. The blood pump further includes a drive unit set to drive the impeller at an actual speed such that a flow is generated between the blood flow inlet and the blood flow outlet. The method includes the steps of receiving pressure data including an indication of vascular pressure and / or an indication of ventricular pressure, and adjusting a speed curve that controls the actual speed of the drive unit based on the received pressure data such that the actual flow rate at the blood flow outlet corresponds to a target flow rate.

[0022] In the case where the blood pump system is used to support the left ventricle, the vascular pressure is the aortic pressure and the ventricular pressure is the left ventricular pressure. Thus, if it is used to support the right ventricle, the vascular pressure is the pulmonary artery pressure and / or the 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 value indicative of the ventricular pressure related to the pressure upstream of or at the blood flow inlet or a pressure value indicative of the vascular pressure related to the pressure downstream of or at the blood flow outlet.

[0024] The step of adjusting the speed curve may further include: reading an ideal speed from a characteristic diagram according to the pressure data and the target flow rate; calculating a set speed of the speed curve according to the ideal speed; and setting the actual speed to the set speed of the speed curve.

[0025] The step of calculating the set speed may further include: considering a speed offset according to the actual speed.

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

[0027] The step of calculating the set speed of the speed curve may further include: determining the inertia of the impeller according to the analysis of the time period of the actual speed and / or the set speed and / or the pressure data; and calculating the set speed considering the inertia of the impeller.

[0028] The method may further include: identifying a repeating pattern in the pressure data.

[0029] The method may further include: adjusting the speed curve according to an optimized mathematical cost function and / or adjusting the speed curve at a predefined frequency, preferably at the predefined frequency of the repeating pattern.

[0030] Compared with the known method for controlling the speed of the drive unit of the blood pump of the above-mentioned blood pump system, the method disclosed according to the present invention has better corresponding features and advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] When read in conjunction with the accompanying drawings, the foregoing invention content and the following detailed description of the preferred embodiments will be better understood. For the purpose of illustrating the present disclosure, reference will be made to the accompanying drawings. However, the scope of the present disclosure is not limited to the specific embodiments disclosed in the drawings. Among them:

[0032] Figure 1 Shown is a schematic diagram of a blood pump system according to the present disclosure;

[0033] Figure 2 Shown is Figure 1Side view of the pump housing of the blood pump of the blood pump system;

[0034] Figure 3 Shown is a graph of left ventricular pressure, aortic pressure, the actual speed of the drive unit of the blood pump, and the set speed for one heartbeat;

[0035] Figure 4 Shown is a characteristic diagram correlating the pressure data of the blood pump with the flow rate;

[0036] Figure 5 Shown is a graph of left ventricular pressure and aortic pressure for 6 consecutive heartbeats;

[0037] Figure 6 Shown is the actual speed of the drive unit of the blood pump and Figure 5 Shown is a graph of the set speed of the heartbeat; and

[0038] Figure 7 Shown is a graph of the target flow rate and the actual flow rate. Detailed Description of the Invention

[0039] Figure 1 Shown is a schematic diagram of a blood pump system 10. The blood pump system 10 includes a blood pump 12, a sensor arrangement 14, a controller 16, and a storage device 18. The blood pump 12, the sensor arrangement 14, and the storage device 18 are connected to the controller 16 by appropriate means (e.g., by cable). Of course, a wireless connection is also possible. Additionally, the storage device 18 can be an integral part of the controller 16.

[0040] The blood pump 12 can be an intravascular blood pump belonging to the product line of the applicant of the present invention. The blood pump 12 includes a pump housing 20 having a blood flow inlet 22 and a blood flow outlet 24. The blood flow inlet 22 is connected to the blood flow outlet 24 through a passage 26. Here, the pump housing 20 includes a plurality of blood flow outlets 24 evenly distributed around the pump housing 20, with reference to also. Figure 2

[0041] The drive unit 28 is disposed within the pump housing 20. The drive unit 28 is configured to drive at a certain speed a pump assembly in the form of an impeller 30 disposed within the pump housing 20, which will be explained in more detail below. Although in the illustrated embodiment the drive unit 28 is disposed within the pump housing 20, the drive unit 28 may also be disposed externally and connected to the impeller 30 by suitable means.

[0042] Rotation of the impeller 30 can be caused by a direct or indirect connection between the drive unit 28 and the impeller 30, such as a magnetic coupling. When the impeller 30 rotates, a blood flow is generated that flows from the blood inlet 22 along the channel 26 to the blood outlet 24. In particular, when placed in a patient's heart, the blood inlet 22 is positioned such that blood from the ventricles of the patient's heart can be drawn into the blood pump 12 and can leave the blood pump 12 via the blood outlet 24 and enter 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, a blood flow generated by the pumping action of the patient's heart can also be added, depending on the patient's heart condition. Thus, the actual blood flow at the blood outlet 24 does not necessarily correspond only to the blood flow generated by the blood pump 12. Instead, the actual blood flow is the total blood flow that leaves the blood pump 12 via the blood outlet 24.

[0043] In Figure 2 the illustrated embodiment, the sensor device 14 includes two sensors 32, 34 disposed on the outer peripheral surface of the pump housing 20. The two sensors 32, 34 may be optical pressure sensors. One of the sensors 32 is positioned near the blood inlet 22 such that the detected pressure conveys an indication of the ventricular pressure, particularly an indication of the left ventricular pressure LVP (when the blood pump 12 is used as left ventricular support). The other sensor 34 is positioned near the blood outlet 24 such that the detected pressure conveys an indication of the vascular pressure, particularly an indication of the aortic pressure AOP (aortic pressure) (when the blood pump 12 is used as left ventricular support). Thus, the sensor device 14 is configured to output pressure data including indications of the aortic pressure AOP and the left ventricular pressure LVP (left ventricular pressure). The blood pump 12 may also be used as right ventricular support. In this case, the right ventricular pressure and the pulmonary artery pressure are indicated by the pressures detected by the two sensors 32, 34. However, in the following embodiments, the blood pump 12 is used as left ventricular support.

[0044] The sensor device 14 can be an externally provided sensor device that transmits pressure data including indications of aortic pressure AOP and left ventricular pressure LVP. For example, the sensor device can include a sensor introduced into the aorta by a catheter to measure aortic pressure AOP or into the left ventricle to measure left ventricular pressure LVP. The pressure data output by the sensor device 14 is sent to the controller 16 for adjusting the speed profile that controls the actual speed AS of the drive unit 28.

[0045] Although in the exemplary embodiment the pressure data includes aortic pressure AOP and left ventricular pressure LVP, for the method of controlling the speed of the drive unit 28 of the blood pump 12 described below, it is sufficient to measure only one of aortic pressure AOP and left ventricular pressure LVP.

[0046] The drive unit 28 drives the impeller 30 at an actual speed AS defined in the speed profile. The speed profile depicts a curve or a set of speed values representing the speed modification of the drive unit 28 during a complete heartbeat or any other suitable time interval. The speed profile can be stored in the storage device 18 and can be adjusted and modified by the controller 16, which will be described in more detail below.

[0047] Initially, the speed profile includes an initial set speed (SS) that drives the drive unit 28 and thus the impeller 30 at a given speed, for example, 24,000 rpm. However, the controller 16 can adjust the speed profile so that the actual flow AF at the blood flow outlet 24 corresponds to a predefined target flow TF, such as 4 liters per minute (l / min), regardless of the pumping action of the patient's heart. Of course, it is not possible to exactly achieve the actual flow AF corresponding to the target flow TF. Therefore, a certain deviation between the actual flow AF and the target flow TF can be tolerated. Thus, the term "corresponds" used herein to describe the relationship between the actual flow AF and the target flow TF should be understood broadly.

[0048] After the blood pump 12 is placed, the drive unit 28 is operated by the controller 16 to drive the impeller 30 using the set speed SS stored in the speed profile. Figure 3 This initial operation for one heartbeat is shown. Therein, the set speed SS of the speed profile at 24,000 rpm is represented by a dashed line on the second ordinate. The actual speed AS of the drive unit 28 and the impeller 30 is represented by a solid black line. The initial drop in speed to a peak of approximately 20,000 RPM is caused by blooming of the impeller 30, for example, due to inertia. Thereafter, the actual speed AS actually corresponds to the set speed SS.

[0049] During this initial phase, the pressure data is recorded by the controller 16 and stored in the storage device 18. AtFigure 3 In this case, for one heartbeat, the left ventricular pressure LVP is represented by a thick gray solid line, and the aortic pressure AOP is represented by a thin black solid line. Next, the controller 16 identifies a recurring pattern in the pressure data, namely, the recurring pattern in the left ventricular pressure LVP. The recurring pattern is a characteristic time point for each heartbeat and is used to distinguish between two heartbeats. The recurring pattern can be represented, for example, by the minimum value of the left ventricular pressure LVP at the end of the diastolic phase, which corresponds to the start of the diastolic period (at approximately Figure 3 the time point 110 in ). In the illustrated embodiment, the recurring pattern is set to the maximum pressure gradient during the systolic phase at the start of systole (at approximately Figure 3 the time point 0 of ). The recurring pattern can also be, for example, the starting point of the systolic phase of the left ventricle, which is the so-called end-diastolic pressure point.

[0050] Next, the controller 16 reads out the ideal speed from a characteristic diagram (CD) stored in the storage device 18. An example of the characteristic diagram is Figure 4 shown. This characteristic diagram includes hydraulic flow curves (P1 to P9) for different speeds of the blood pump 12, which relate the pressure difference or pressure gradient across the blood pump 12 to the achieved blood flow rate. For example, the hydraulic flow curve P5 represents a speed of 24,000 rpm. The hydraulic flow curves rise and fall in steps of 2,000 rpm. Thus, the hydraulic flow curve P6 represents a speed of 26,000 rpm, and the hydraulic flow curve P4 represents a speed of 22,000 rpm. The hydraulic flow curves P1 to P9 can be individual flow curves for a specific blood pump 12, or they can be hydraulic flow curves for an entire type series of blood pumps 12 or a group of blood pumps within a type series.

[0051] The pressure difference across the blood pump 12 corresponds to the pressure gradient between the blood flow inlet 22 and the blood flow outlet 24, and thus corresponds to the pressure gradient between the left ventricular pressure LVP and the aortic pressure AOP. The controller 16 derives from the characteristic diagram CD the ideal speed to reach the desired target flow rate TF, e.g., 4 l / min, at each time point within one heartbeat. In the case where the hydraulic flow curves P1 to P9 are not given for a certain pressure difference, the controller 16 is set to calculate the ideal speed according to interpolation and extrapolation between the adjacent hydraulic flow curves P1 to P9. Then, the controller 16 calculates the ideal speed at each time point within one heartbeat thus derived to derive the set speed SS of the drive unit 28 at each time point. In doing so, the controller 16 is set to take into account the speed offset according to the actual speed AS of the drive unit 28 during this initial phase. In the described exemplary embodiment, 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 influence on the pressure gradient across the blood pump 12 and thus on the ideal speed derived from the characteristic diagram. Therefore, a fixed speed offset is deducted from the derived ideal speed. In the exemplary embodiment, the speed offset is set to 1,600 rpm. However, the speed offset does not need to be a fixed value but can be determined according to other variables, such as pressure data.

[0052] Then the controller 16 stores the calculated set speed SS in the speed curve. For the next heartbeat starting in the repetitive mode, the actual speed AS of the drive unit 28 is set to the set speed SS corresponding to the speed curve. In fact, the drive unit 28 is operated at different speeds according to the modulated set speed SS during one heartbeat such that the actual flow rate AF at the blood flow outlet 24 corresponds to the predefined and desired target flow rate TF, e.g., 4 l / min. For each repetitive mode of each successive heartbeat, the speed curve is replayed from the beginning.

[0053] The controller 16 is further set to store the time periods of various data in the storage device 18, in particular the pressure data, the set speed SS, and the actual speed AS. By analyzing this data, the controller 16 can derive the inertia of the impeller 30 based on the comparison between the time point when the actual speed AS is set to the set speed SS and the time point when the expected actual speed AS is reached. Based on this, the controller 16 determines information about the inertia of the impeller 30 and adjusts the speed curve to take into account the inertia of the impeller 30. The controller 16 can derive a fixed value considering the inertia or can derive a function of the inertia according to the set speed SS.

[0054] During normal operation of the blood pump 12, the speed curve is re-evaluated to account for changing conditions. Thus, the method for adjusting the speed curve described above is repeated, for example, every five heartbeats. Thus, once the speed curve has been adjusted, it is assumed that the conditions for the next four consecutive heartbeats remain constant. Figure 5 Shown is a time period of left ventricular pressure LVP (thick grey line) and aortic pressure AOP (thin black solid line) for six consecutive heartbeats. Thus, the speed curve will be adjusted again during the last heartbeat, as Figure 5 shown, starting at approximately time point 1190. The thin vertical lines are used to distinguish the repeating pattern of one heartbeat from the next.

[0055] In addition, a time period of the set speed SS (dashed line) and the actual speed AS (black solid line) is shown as Figure 6 shown. As shown, during an initial phase lasting until approximately time point 250, the set speed SS roughly corresponds to an initial speed of 24,000 rpm. Thereafter, the actual speed AS of the drive unit 28 follows the set speed SS specified in the speed curve. Next, during the first heartbeat between approximately time points 250 and 480, the inertia of the impeller 30 has not been taken into account. During the next heartbeat, the controller 16 has taken into account the inertia of the impeller 30 and the actual speed AS closely follows the set speed SS.

[0056] In summary, in this way the actual flow rate AF delivered at the blood flow outlet 24 practically corresponds to the expected target flow rate TF of 4 l / min, as Figure 7 shown. In Figure 7 , the actual flow rate AF is represented by a solid black line, while the target flow rate TF is represented by a dashed line. Of course, a certain deviation between the actual flow rate AF and the target flow rate TF is admissible, provided that the deviation is within a predefined limit. Thus, the speed curve can be adjusted additionally or alternatively based on a minimized mathematical cost function. The controller 16 can be set to calculate the statistical variability between the actual flow rate AF and the target flow rate TF. For this purpose, an appropriate control error (such as standard deviation, standard error or root mean square error) needs to be calculated and can be compared with a predefined threshold or acceptance interval. Once the error magnitude exceeds the threshold or acceptance interval, the speed curve is adjusted. In addition, the controller 16 can also be set to adjust the speed curve at given time intervals, for example, at the first heartbeat after every five seconds. Additionally, the controller 16 can be set to apply a signal filter, thereby ignoring possible erroneous measurements and not causing unnecessary adjustment of the speed curve. The signal filter can be, for example, a low-pass filter, a high-pass filter, a band-pass filter and / or a moving average filter.

[0057] EXEMPLARY IMPLEMENTATIONS

[0058] As previously described, the technology described in the present invention can be implemented in various ways. In this regard, the foregoing disclosure is intended to include, but not limited to, the systems, methods, and their combinations and sub - combinations set forth in the following exemplary embodiments. The preferred embodiments will be described in the following paragraphs:

[0059] An A1 blood pump system includes: a blood pump, in particular an intravascular blood pump, having a pump housing with a blood flow inlet and a blood flow outlet connected by a channel, a pump assembly disposed within the pump housing, a drive unit configured to drive the pump assembly at an actual speed to create a flow between the blood flow inlet and the blood flow outlet; a sensor device configured to output pressure data including an indication of vascular pressure and / or an indication of ventricular pressure; and a controller, wherein the controller is also configured to adjust a speed curve that controls the actual speed of the drive unit based on the pressure data output by the sensor device such that the actual flow rate at the blood flow outlet corresponds to a target flow rate.

[0060] An A2 blood pump system as described in paragraph A1, wherein the pump assembly is an impeller.

[0061] An A3 blood pump system as described in paragraph A1 or A2, wherein the sensor device is configured to output pressure data including at least one of a pressure value indicative of left ventricular pressure related to the pressure upstream of or at the blood flow inlet or a pressure value indicative of aortic pressure related to the pressure downstream of or at the blood flow outlet.

[0062] An A4 blood pump system as described in any of the foregoing paragraphs, wherein the blood pump includes the sensor device.

[0063] An A5 blood pump system as described in paragraph A4, wherein the sensor device includes two sensors.

[0064] An A6 blood pump system as described in paragraph A5, wherein one sensor is disposed near the blood flow inlet and / or the other sensor is disposed near the blood flow outlet.

[0065] An A7 blood pump system as described in paragraph A5 or A6, wherein the sensor is an optical sensor, in particular an optical pressure sensor.

[0066] An A8 blood pump system as described in any of paragraphs A1 to A3 above, wherein the sensor device is separate from the blood pump.

[0067] An A9 blood pump system as described in any of paragraphs A1 to A8 above, wherein the blood pump system further includes a storage device.

[0068] An A10 blood pump system as described in paragraph A9, wherein a characteristic map associating the pressure data with the flow rate of the drive unit is stored in the storage device.

[0069] A blood pump system as described in paragraph A10, wherein the controller is configured to read an ideal speed from a characteristic diagram according to pressure data and a target flow rate.

[0070] A blood pump system as described in paragraph A11, wherein the controller is further configured to calculate a set speed of a speed curve according to the ideal speed and set the actual speed to the set speed of the speed curve.

[0071] A blood pump system as described in paragraph A12, wherein the controller is further configured to calculate a set speed considering a speed offset according to the actual speed.

[0072] A blood pump system as described in paragraph A13, wherein the controller is further configured to determine an ideal speed according to interpolation and extrapolation methods.

[0073] A blood pump system as described in any one of paragraphs A10 to A14 above, wherein the characteristic diagram is an individual characteristic diagram for a specific blood pump.

[0074] A blood pump system as described in any one of paragraphs A10 to A14 above, wherein the characteristic diagram is a characteristic diagram of a type series of blood pumps or a group of blood pumps within a type series of blood pumps.

[0075] A blood pump system as described in any one of paragraphs A10 to A16 above, wherein the characteristic diagram includes a plurality of hydraulic flow curves for different speeds of the drive unit.

[0076] A blood pump system as described in any one of paragraphs A9 to A17 above, wherein the controller is further configured to store a time period of the set speed and / or a time period of the ideal speed and / or a time period of the actual speed and / or a time period of the pressure data in a storage device.

[0077] A blood pump system as described in paragraph A18, wherein the controller is further configured to determine the inertia of the impeller according to an analysis of a time period of the actual speed and / or the set speed and / or a time period of the pressure data, and calculate a set speed considering the inertia of the pump assembly.

[0078] A blood pump system as described in any one of paragraphs A1 to A19 above, wherein the controller is further configured to identify a repeating pattern in the pressure data.

[0079] A blood pump system as described in paragraph A20, wherein the repeating pattern is a pattern in a pressure signal indicating ventricular pressure.

[0080] A blood pump system as described in paragraph A20 or A21, where this repeating pattern is a minimum at the end of the diastolic phase of the ventricle, or where the repeating pattern is the maximum pressure gradient during the systolic phase at the start of systole, or where the repeating pattern can be the starting point of the systolic phase of the left ventricle, in particular the end-diastolic pressure point.

[0081] A blood pump system as described in any one of paragraphs A1 to A22 above, where the controller is also set to repeat the adjustment of the speed curve according to an optimized mathematical cost function, and / or to adjust the speed curve at a predefined frequency, preferably at the predefined frequency of the repeating pattern.

[0082] A blood pump system as described in paragraph A24, where the controller is set to calculate the statistical dispersion or variability between an actual value and a set value, preferably between an actual flow rate and a target flow rate.

[0083] A blood pump system as described in any one of paragraphs A1 to A24 above, where the controller is also set to apply a signal filter.

[0084] A blood pump system as described in any one of paragraphs A1 to A25 above, where the vascular pressure is the aortic pressure, and / or where the ventricular pressure is the left ventricular pressure.

[0085] A blood pump system as described in paragraph A26, where the blood pump system is a left ventricular support blood pump system.

[0086] A blood pump system as described in any one of paragraphs A1 to A25 above, where the vascular pressure is the pulmonary artery pressure and / or where the vascular pressure is the central venous pressure, and the ventricular pressure is the right ventricular pressure.

[0087] A blood pump system as described in paragraph A28, where the blood pump system is a right ventricular support blood pump system.

[0088] A method for controlling the speed of a drive unit of a blood pump, in particular an intravascular blood pump, where the blood pump includes a pump housing having a blood flow inlet and a blood flow outlet connected by a channel, a pump assembly disposed within the pump housing, and a drive unit configured to drive an impeller at an actual speed such that a flow is generated between the blood flow inlet and the blood flow outlet; the method including the steps of: receiving pressure data including an indication of vascular pressure and / or an indication of ventricular pressure; adjusting a speed curve that controls the actual speed of the drive unit based on the received pressure data such that the actual flow rate at the blood flow outlet corresponds to a target flow rate.

[0089] The method as described in paragraph B1, where the pump assembly is an impeller.

[0090] The method as described in paragraph B1 or B2, wherein the step of receiving pressure data further comprises: receiving at least one of a pressure related to the pressure at or upstream of the blood flow inlet as an indication of ventricular pressure or a pressure related to the pressure at or downstream of the blood flow outlet as an indication of vascular pressure.

[0091] The method as described in any one of paragraphs B1 to B3 above, wherein the step of adjusting the velocity curve further comprises: reading an ideal velocity from a characteristic diagram associating the pressure data with a target flow rate according to the pressure data.

[0092] The method as described in paragraph B4, wherein the step of adjusting the velocity curve further comprises: calculating a set velocity of the velocity curve according to the ideal velocity.

[0093] The method as described in paragraph B5, wherein the step of adjusting the velocity curve further comprises: determining the ideal velocity according to interpolation and extrapolation methods.

[0094] The method as described in any one of paragraphs B4 to B6 above, wherein the characteristic diagram is an individual characteristic diagram of a specific blood pump.

[0095] The method as described in any one of paragraphs B4 or B6 above, wherein the characteristic diagram is a characteristic diagram of a type series of blood pumps or a group of blood pumps within a type series of blood pumps.

[0096] The method as described in any one of paragraphs B4 to B8 above, wherein the characteristic diagram includes a plurality of hydraulic flow curves for different speeds of the drive unit.

[0097] The method as described in any one of paragraphs B5 to B9 above, wherein the step of adjusting the velocity curve further comprises: setting the actual velocity to the set velocity of the velocity curve.

[0098] The method as described in any one of paragraphs B5 to B10 above, wherein the step of calculating the set velocity further comprises: considering a velocity offset according to the actual velocity.

[0099] The method as described in any one of paragraphs B1 to B11 above, the method further comprises: storing a period of the set velocity and / or a period of the ideal velocity and / or a period of the actual velocity and / or a period of the pressure data.

[0100] The method as described in paragraph B12, wherein the step of calculating the set velocity further comprises: determining the inertia of the pump assembly according to an analysis of the period of the actual velocity and / or the pressure data.

[0101] The method as described in paragraph B13, wherein the step of calculating the set velocity further comprises: considering the inertia of the pump assembly to calculate the set velocity.

[0102] B15 The method as described in any one of paragraphs B1 to B14 above, the method further comprising: identifying a repeating pattern in the pressure data.

[0103] B16 The method as described in paragraph B15, wherein the step of identifying the repeating pattern comprises: identifying a repeating pattern in the pressure signal indicative of ventricular pressure.

[0104] B17 The method as described in any one of paragraphs B15 or B16 above, wherein the step of identifying the repeating pattern comprises: identifying a minimum value at the end of the diastolic phase of the left ventricle, or identifying a maximum pressure gradient during the systolic phase at the start of systole, or identifying the starting point of the left ventricular systolic phase, in particular the end-diastolic pressure point.

[0105] B18 The method as described in any one of paragraphs B1 to B17 above, wherein the method further comprises: adjusting the velocity curve according to an optimized mathematical cost function; and / or adjusting the velocity curve at a predefined frequency, preferably at the predefined frequency of the repeating pattern.

[0106] B19 The method as described in paragraph B18, wherein the step of adjusting the velocity curve according to an optimized mathematical cost function further comprises: calculating the statistical dispersion or variability between the actual value and the set value, preferably between the actual flow rate and the target flow rate.

[0107] B20 The method as described in any one of paragraphs B1 to B19 above, wherein the method further comprises: applying a signal filter to the pressure data and / or the velocity curve and / or the set velocity.

[0108] B21 The method as described in any one of paragraphs B1 to B20 above, wherein the vascular pressure is aortic pressure, and / or wherein the ventricular pressure is left ventricular pressure.

[0109] B22 The method as described in paragraph B21, wherein the blood pump is a left ventricular support blood pump.

[0110] B23 The method as described in any one of paragraphs B1 to B20 above, wherein the vascular pressure is pulmonary artery pressure and / or wherein the vascular pressure is central venous pressure, and the ventricular pressure is right ventricular pressure.

[0111] B24 The method as described in paragraph B23, wherein the blood pump is a right ventricular support blood pump.

[0112] As used herein, the terms "about", "substantially", "essentially", "nearly" and similar terms are intended to give the subject matter of the present invention a broad meaning consistent with the common and accepted usage of those skilled in the art. After reading the present invention, those skilled in the art should understand that these terms are intended to allow the description of certain features without restricting the scope of these features to the exact numerical ranges provided. Therefore, these terms should be interpreted as indicating non-material or insignificant modifications or changes to the described subject matter and are considered to be within the scope of the present invention.

[0113] Symbol Description

[0114] 10: Blood pump system

[0115] 12: Blood pump

[0116] 14: Sensor device

[0117] 16: Controller

[0118] 18: Storage device

[0119] 20: Pump housing

[0120] 22: Blood flow inlet

[0121] 24: Blood flow outlet

[0122] 26: Channel

[0123] 28: Driving unit

[0124] 30: Impeller

[0125] 32: Sensor

[0126] 34: Sensor

[0127] AF: Actual flow

[0128] AOP: Aortic pressure

[0129] AS: Actual speed

[0130] CD: Characteristic diagram

[0131] LVP: Left ventricular pressure

[0132] P1, P2, P3, P4, P5, P6, P7, P8, P9: Hydraulic flow curve

[0133] SS: Set speed

[0134] TF: Target flow.

Claims

1. A blood pump system (10), comprising: A blood pump (12), particularly an intravascular blood pump, having a pump housing (20), an impeller (30) and a drive unit (28), the pump housing (20) having a blood flow inlet (22) and a blood flow outlet (24) connected by a channel (26), the impeller (30) being arranged within the pump housing (20), the drive unit (28) being set to drive the impeller (30) at an actual speed (AS) such that a flow is generated between the blood flow inlet (22) and the blood flow outlet (24); A sensor device (14), the sensor device (14) being set to output pressure data including an indication of the aortic pressure (AOP) and / or an indication of the left ventricular pressure (LVP); and A controller (16); Wherein the controller (16) is further set to adjust a speed curve for controlling the actual speed (AS) of the drive unit (28) based on the pressure data output by the sensor device (14) such that the actual flow (AF) at the blood flow outlet (24) corresponds to a target flow (TF).

2. The blood pump system according to claim 1, wherein The sensor device (14) is set to output pressure data, the pressure data including at least one of a pressure value as an indication of the left ventricular pressure (LVP) related to the pressure upstream of or at the blood flow inlet (22) or a pressure value as an indication of the aortic pressure (AOP) related to the pressure downstream of or at the blood flow outlet (24).

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

4. The blood pump system according to claim 3, wherein The controller (16) is further set to calculate the set speed (SS) taking into account a speed offset based on the actual speed (AS).

5. The blood pump system according to claim 3 or 4, wherein The controller (16) is also configured to store a time period of the set speed (SS) and / or a time period of the desired speed and / or a time period of the actual speed (AS) and / or a time period of the pressure data in the storage device (18), preferably, wherein the controller (16) is also configured to determine the inertia of the impeller (30) based on an analysis of the time period of the actual speed (AS) and / or the time period of the set speed and / or the time period of the pressure data, and to calculate the set speed (SS) taking into account the inertia of the impeller (30).

6. The blood pump system according to any one of claims 1 to 5, wherein, the controller (16) is also configured to identify a repeating pattern in the pressure data.

7. The blood pump system according to any one of claims 1 to 6, wherein, the controller (16) is also configured to repeatedly adjust the speed curve according to an optimized mathematical cost function and / or to adjust the speed curve at a predefined frequency, preferably at a predefined frequency of the repeating pattern.

8. A method for controlling the speed of a drive unit (28) of a blood pump (12), in particular an intravascular blood pump, wherein the blood pump (12) comprises: a pump housing (20) having a blood flow inlet (22) and a blood flow outlet (24) connected by a channel (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 is generated between the blood flow inlet (22) and the blood flow outlet (24); wherein the method comprises the following steps: receiving pressure data comprising an indication of the aortic pressure (AOP) and / or an indication of the left ventricular pressure (LVP); adjusting a speed curve for controlling the actual speed (AS) of the drive unit (28) based on the received pressure data such that the actual flow (AF) at the blood flow outlet (24) corresponds to a target flow (TF).

9. The method according to claim 8, wherein the step of receiving pressure data further comprises: receiving at least one of a pressure value as an indication of the left ventricular pressure (LVP) related to the pressure upstream of the blood flow inlet (22) or at the blood flow inlet (22) or a pressure value as an indication of the aortic pressure (AOP) related to the pressure downstream of the blood flow outlet (24) or at the blood flow outlet (24).

10. The method according to claim 8, wherein the step of adjusting the speed curve further comprises: reading a desired speed from a characteristic diagram (CD) associating the pressure data with the target flow (TF) based on the pressure data; calculating a set speed (SS) of the speed curve based on the desired speed; and setting the actual speed (AS) to the set speed (SS) of the speed curve.

11. The method according to claim 10, wherein the step of calculating the set speed (SS) further comprises: Considering a speed offset based on the actual speed (AS).

12. The method according to any one of claims 8 to 11, wherein the method further comprises: Storing the period of the set speed (SS) and / or the period of the desired speed and / or the period of the actual speed (AS) and / or the period of the pressure data.

13. The method according to claim 12, wherein the step of calculating the set speed (SS) further comprises: Determining the inertia of the impeller (30) based on an analysis of the period of the actual speed (AS) and / or the pressure data; And Considering the inertia of the impeller (30) to calculate the set speed (SS).

14. The method according to any one of claims 8 to 13, wherein the method further comprises: Identifying a repeating pattern in the pressure data.

15. The method according to any one of claims 8 to 14, wherein the method further comprises: Adjusting the speed curve according to an optimized mathematical cost function; And / or Adjusting the speed curve at a predefined frequency, preferably at the predefined frequency of the repeating pattern.

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