Blood pump

Abstract

This invention relates to a control device (100) for controlling the blood flow Q of an intravascular blood pump (50) for percutaneous insertion into a patient's blood vessel. 泵 (t), the blood pump (50) includes a pump unit (52) and a drive unit (51) for driving the pump unit, and the pump unit is configured to deliver blood from a blood inlet (54) toward a blood outlet (56), wherein the control device (100) is configured to operate the blood pump (50) in a selectable zero-flow control mode, wherein the blood flow command signal Q 泵 设定 (t) is selected, and the control device includes a first controller (401) and a second controller (402), wherein the first controller (401) is configured to adjust the speed command signal n for the drive unit (51). 泵 设定 (t) to control blood flow Q 泵 (t), and the second controller (402) is configured to control the drive speed n of the drive unit (51). 泵 (t). In addition, the present invention relates to a system comprising an intravascular blood pump (50) for assisting the heart and a control device (100) for controlling the blood pump (50).

Description

[0001] Divisional application

[0002] This application is a divisional application of patent application No. 201880053604.9, filed on August 17, 2018, entitled "Blood Pump". Technical Field

[0003] This invention relates to a blood pump, and more particularly to an intravascular blood pump for percutaneous insertion into a patient's blood vessel. Specifically, the invention relates to a specific control method for a percutaneously insertable blood pump, a corresponding control device, and a system including the control device and the blood pump. While the invention is configured for, and particularly for, intravascular blood pumps, it is less relevant to larger blood pumps, such as VADs not placed inside a blood vessel or heart but located outside the patient's heart, for example, implanted in the chest cavity. Background Technology

[0004] Ventricular assist devices (VADs) are used to support the function of a patient's heart, such as left ventricular assist devices (LVADs) or right ventricular assist devices (RVADs). While a typical VAD connects to the patient's heart via a suitable catheter and is implanted in the chest cavity outside the heart, percutaneous intravascular blood pumps typically consist of a catheter and a pump unit inserted through a channel into a blood vessel and further into the patient's heart, for example, through the aorta into the left ventricle. The pump unit may be located at the distal end of the catheter and includes a blood inlet and a blood outlet, as well as a cannula. Blood flow is generated, for example, through the rotor or impeller of the pump unit via the cannula. For example, the cannula may extend through the aortic valve, with the blood inlet located at the distal end of the cannula in the left ventricle and the blood outlet located at the proximal end of the cannula in the aorta. Blood flow is generated by overcoming the pressure difference between the inlet and outlet.

[0005] Among other things, an important aspect of intravascular blood pumps (hereinafter referred to as "pumps") is the implantation of the pump into the patient and thus confirmation that natural cardiac function has been restored. This can be accomplished, for example, by appropriately reducing the amount of assistance provided by the pump so that once the heart is found to have fully recovered, the pump can eventually be implanted. In this respect, timely determination of the precise point for implantation is less important in larger VADs, which are typically implanted in the patient's chest cavity and designed for long-term use.

[0006] To date, no known physical signal has been found to adequately indicate the state of cardiac recovery once an intravascular pump is implanted. It is impossible to know the function of the heart without assistance when the pump is assisted. Furthermore, when the pump is turned off, backflow of fluid through the cannula makes it impossible to know the function of the heart without assistance. Backflow is a particular problem with intravascular pumps because the pump, more specifically the cannula of the pump, extends through a heart valve, such as the aortic valve, creating an open path through the valve that allows backflow into the heart when the pump is not activated. This problem typically does not occur with extravascular devices, as they do not extend through the heart valve but rather bypass it, such as VADs placed outside the heart, for example, in the thoracic cavity.

[0007] In current technology, the pump rate setting is gradually and manually reduced by a physician based on professional experience, for example, by one stage. After the pump rate is reduced, the mean aortic pressure is monitored. Some institutions use echocardiography to assess left ventricular volume and measure continuous cardiac output. If the mean aortic pressure remains stable, it is assumed that the heart is capable of taking over the pumping function. However, if the mean aortic pressure decreases, it is assumed that the heart still needs more assistance, thus requiring the pump rate to be increased again. Furthermore, a so-called on / off method is applied before the blood pump is implanted. In doing so, the pump rate is significantly reduced, for example, for several hours, during which the patient's physiological condition and, in particular, ventricular dilation are observed, for example, based on echocardiography (ECHO) measurements and / or cardiac ventriculography. ECHO can provide information about the heart, such as size and shape, such as quantification of internal chamber size, pumping capacity, and allows for the calculation of cardiac output, ejection fraction, and diastolic function. Cardiac ventriculography involves injecting contrast agent into the ventricles of the heart to measure the amount of blood pumped. The measurements obtained through cardiac ventriculography are ejection fraction, stroke volume, and cardiac output.

[0008] When the blood pump is turned off and the heart still cannot function properly, the ventricles, no longer being assisted, will dilate significantly, resulting in insufficient blood volume being ejected from the ventricles during systole, leading to an increase in left ventricular end-diastolic volume and pressure. In other words, due to the reduced pump rate, the heart may be under acute overload corresponding to a heart that has not yet recovered. This could lead to setbacks in treatment lasting several days.

[0009] Therefore, the actual monitoring process before the implantation of the blood pump is more or less a trial-and-error process, in which the pump rate is further reduced if the patient's condition remains stable, and the pump rate needs to be increased again if the condition worsens. Summary of the Invention

[0010] One object of the present invention is to provide an improved control method for an intravascular blood pump and a corresponding improved control device, as well as a system including the control device and the intravascular blood pump, wherein the blood pump can be operated such that a better assessment of the state of cardiac recovery can be determined.

[0011] This objective is achieved through the features of each technical solution. Preferred embodiments and further developments are defined in each further technical solution.

[0012] For clarity, the following definitions will be used in this article:

[0013] The term “characteristic parameters of the heart” should be understood as specific values ​​derived from physiological signals that characterize the condition of the heart with respect to, for example, load (such as overload or deload) and / or physiological condition (such as weak, strong, or recovering).

[0014] The human circulatory system is the organ system that allows blood to circulate. Its basic components are the heart, blood, and blood vessels. The circulatory system includes pulmonary circulation, the "circulation" that passes through the lungs where blood is oxygenated, and systemic circulation, the "circulation" that passes through the rest of the body to provide oxygenated blood.

[0015] The improvements disclosed herein relate to blood pumps that include settable blood flow levels. For example, in the case of a rotary blood pump, the “settable blood flow level” may be a discrete blood flow level within a range defined by a minimum blood flow and a maximum blood flow, or a continuously settable blood flow level.

[0016] The basic idea of ​​the control device and corresponding control method for controlling an intravascular blood pump proposed herein is to provide a mode in which the current blood flow through the blood pump can be maintained at a very low, preferably zero, level compared to the blood outlet capacity of the blood pump. Preferably, the blood flow through the blood pump is maintained between 0 and 1 L / min, more preferably between 0 and 0.5 L / min, between 0 and 0.2 L / min, or even between 0 and 0.1 L / min. Most preferably, the blood flow through the blood pump is maintained at approximately zero flow. In this case, the blood pump is controlled such that neither positive nor negative blood flow is generated. This operating mode is referred to herein as the "zero flow control mode". For example, zero flow can be established and / or maintained by controlling the drive unit of the blood pump, such as a motor, particularly the current drive speed of the drive unit, such as the motor, and thus the blood flow, such that only the current pressure difference between the blood inlet and the blood outlet of the blood pump is compensated.

[0017] In this context, "zero flow" must be understood as zero flow or extremely low blood flow. Since the purpose of zero flow control mode is to obtain information about the heart's recovery status, implementing extremely low blood flow may be sufficient. Low blood flow, such as up to 0.1 L / min, up to 0.2 L / min, or even up to 0.5 L / min, should be considered "zero flow" in this context. Under no circumstances should "zero flow" be negative. In other words, zero flow should not allow any backflow through the blood pump.

[0018] In this context, an intravascular blood pump for percutaneous insertion includes a catheter and a pump unit inserted via a blood vessel into a patient's heart, such as into the left ventricle via the aorta. The pump unit includes a blood inlet and a blood outlet, and a cannula through which blood flow is generated by a drive unit for driving the pump unit. For example, the pump unit may include a rotor or impeller driven by a drive unit, such as an electric motor, to deliver blood from the blood inlet toward the blood outlet. For example, the cannula may extend through the aortic valve, such that the blood inlet is located in the left ventricle at the distal end of the cannula and the blood outlet is located in the aorta at the proximal end of the cannula. The intravascular blood pump may have a maximum outer diameter ranging from about 12 French (F) (about 4 mm) to about 21 French (F) (about 7 mm), such as 12F (about 4 mm), 18F (about 6 mm), or 21F (about 7 mm), which is typically the maximum outer diameter of the pump unit. The catheter may have an outer diameter smaller than that of the pump unit, such as 9F (about 3 mm).

[0019] The heart's natural function creates a pressure difference, such as between the aorta and the left ventricle. For positive blood flow to be generated, the blood pump must overcome this pressure difference. Otherwise, if the pressure generated by the blood pump is too low, the existing pressure difference between the aorta and the left ventricle will cause backflow into the left ventricle.

[0020] By applying zero-flow control mode, the blood pump provides no or very little assistance to the heart and advantageously avoids backflow; that is, the blood pump does not allow blood to flow back. For example, in the case of left ventricular assist, during diastole, the blood pump does not allow blood to flow back from the aorta into the left ventricle.

[0021] By applying zero-flow control mode, the blood pump's drive unit, such as the rotor or impeller, continues to rotate. Therefore, the risk of thrombosis is reduced because of this still-moving part.

[0022] With the help of the zero-flow operating mode, the auxiliary blood flow provided to the heart by the blood pump is set to virtually zero. "Visibly zero" means that any blood flow still generated must be at least negligible, but never negative, that is, the blood pump is not allowed to backflow through the blood pump.

[0023] In zero-flow operation mode, the entire effort to overcome the pressure difference between the assisted ventricle, such as the left ventricle, and the adjacent vessel, such as the aorta, is provided solely by the heart. Thus, zero-flow operation mode allows for monitoring one or more suitable characteristic parameters of the heart, which can be used or interpreted as indicators of the heart's recovery status.

[0024] Preferably, the blood flow rate of the blood pump is related to the drive speed of the drive unit, such as the motor, the current supplied to the drive unit, and / or the pressure difference between the outlet and inlet of the blood pump. This relationship can be stored in memory, for example, in a lookup table, as will be described in more detail below. That is, the command signal value can be stored in the memory of the control device or in the memory of the blood pump accessible to the control device.

[0025] The first aspect provides a control device for controlling the blood flow of an intravascular blood pump used for percutaneous insertion into a patient's blood vessel. Q 泵 (t) The blood pump includes a pump unit and a drive unit for driving the pump unit, the pump unit being configured to deliver blood from a blood inlet to a blood outlet. A control device is configured to operate the blood pump in a selectable zero-flow control mode, wherein a blood flow command signal... Q 泵 设定 (t) Selected. The control device includes a first controller and a second controller, wherein the first controller is configured to adjust the speed command signal for the drive unit. n 泵 设定 (t) To control blood flow Q 泵 (t) The second controller is configured to control the drive speed of the drive unit. n 泵 (t) More specifically, the control device is specifically configured to control the intravascular blood pump, or more generally, as will be described in more detail below, a low-inertia device.

[0026] Preferably, the intravascular blood pump includes a cannula between a blood inlet and a blood outlet, through which blood flow is generated by the pump unit. In operation, the cannula may extend, for example, through the aortic valve, with the blood inlet located in the left ventricle and the blood outlet located in the aorta.

[0027] For example, the controlled blood flow rate can be constant. By compensating for the current pressure difference between the blood inlet and outlet, the actual blood flow through the blood pump becomes zero. That is, in zero-flow control mode, the current pressure difference between the blood outlet and inlet is offset by controlling the blood flow rate through the control of the drive speed.

[0028] Preferably, the first controller is configured to respond to blood flow command signals. Q 泵 设定 (t) With blood flow Q 泵 (t) The difference between ΔQ Determine the speed command signal n 泵 设定 (t) In other words, the first controller is configured to record the actual blood flow. Q 泵 (t) Blood flow command signal Q 泵 设定 (t) Compared to determine the speed command signal n 泵 设定 (t) .

[0029] Preferably, the second controller is configured to adjust the drive current supplied to the drive unit. I 泵 (t) To control drive speed n 泵 (t) For example, the drive unit may include a motor, particularly an electric motor, and the adjusted drive current may be the motor current supplied to the electric motor. Therefore, in the case of a rotary drive unit, the command speed signal of the drive unit... n 泵 设定 (t) and setting drive speed n 泵 设定 (t) It can be the rotational speed. The electric motor can be located in the pump unit and directly or indirectly coupled to the impeller, for example, by means of mechanical connection or magnetic coupling.

[0030] Preferably, the first controller and the second controller are part of a cascaded control system, in which the first controller is an external controller and the second controller is an internal controller. The external controller can be embedded in an external control loop and can regulate the blood flow generated by the blood pump by comparing a blood flow command signal with the generated blood flow and by setting a setpoint in the internal control loop, i.e., the blood pump speed command signal. The internal controller is part of an internal control loop and can control the speed of the blood pump by adjusting the motor current accordingly.

[0031] Preferably, the control device is configured to control the blood flow during a predetermined zero-flow control period. Q 泵 (t) .

[0032] For example, the predetermined zero-flow control period can be set as a segment of a cardiac cycle in a continuously assisted heart. That is, the zero-flow control mode is applied only briefly "within one beat". In this case, the predetermined zero-flow period is preferably small compared to the duration of the cardiac cycle. In this way, since the duration of unassisted heart is kept to a minimum, information on the heart's recovery state can be collected without any overload on the heart.

[0033] For example, a predetermined zero-flow control period can be set to last for at least one complete cardiac cycle or a predetermined number of complete coherent cardiac cycles.

[0034] Preferably, the control device is configured to synchronize the zero-flow control period with the occurrence of at least one characteristic cardiac cycle event. For example, the start and / or end of the zero-flow control period is synchronized with the occurrence of the at least one characteristic cardiac cycle event. In particular, the start and end of the zero-flow control period can be synchronized with the occurrence of two characteristic cardiac cycle events. In this way, the zero-flow control mode can be set as a time interval of cardiac cycles, during which specific characteristic parameters of the heart can provide specific useful information, directly or indirectly, indicating the state of cardiac recovery.

[0035] For example, a characteristic cardiac cycle event could be the opening or closing of the aortic valve. For instance, the control device could be configured to detect aortic valve opening by one of the following: the presence of a balance between left ventricular and aortic pressures, the appearance of an R wave on an electrocardiogram (ECG), or a signal from a patient with an assisted heart.

[0036] Further characteristic cardiac cycle events could include the opening of the mitral valve, the closing of the mitral valve, or the occurrence of end-diastolic left ventricular pressure.

[0037] Preferably, the control device is configured to monitor the values ​​of one or more characteristic cardiac parameters. That is, the control device can be configured to monitor one or more characteristic cardiac parameters each time the zero-flow control mode is applied, in zero-flow control mode.

[0038] Preferably, the control device is configured to operate the intravascular blood pump in a zero-flow control mode periodically or randomly. The periodic or random application of the zero-flow control mode can be performed over a predetermined time span, for example, from segments of the cardiac cycle up to several days.

[0039] Preferably, the control device is configured to identify trends in one or more values ​​of the monitored characteristic cardiac parameters. Such trends in the monitored characteristic cardiac parameters can serve as indicators of the heart's recovery status or the state of cardiac recovery itself; that is, they can help determine whether there is progress in recovery. The trends can be communicated to a physician via the control device's user interface, enabling the physician to make decisions regarding the heart's recovery status.

[0040] For example, the at least one characteristic parameter of the heart could be arterial blood pressure measured each time a zero-flow operating mode is established. With the application of zero-flow control mode, arterial blood pressure may decrease. A drop in pressure reaching a critical value or showing a critical decrease indicates that the blood pump cannot be implanted because the heart has not yet recovered. In another example, arterial blood pressure may remain stable or show only a small drop during zero-flow control mode. In this case, it can be assumed that the heart has fully recovered and the blood pump can be implanted.

[0041] Preferably, at least one characteristic cardiac parameter is at least one of the following: arterial pressure pulsatility (AOP). 最大 -AOP| 最小 Mean arterial pressure, cardiac contractility dLVP(t) / dt| 最大 diastolic function of the heart dLVP(t) / dt| 最小 Heart rate (HR).

[0042] The control device can be configured to measure blood flow using sensors. Q 泵 (t) Calculate or estimate blood flow Q 泵 (t) For example, the pressure difference between the blood outlet and the blood inlet can be determined by corresponding pressure sensors located at the inlet and outlet of the blood pump, namely, a pressure sensor capturing the afterload of the blood pump and a pressure sensor capturing the preload of the blood pump. Alternatively or additionally, the blood pump may include a sensor configured to measure the pressure difference directly only. Furthermore, in this alternative, the pressure difference between the blood outlet and the blood inlet can be estimated, measured, or calculated.

[0043] Blood flow Q 泵 (t) A lookup table can be used to determine, rather than measuring, blood flow. Q 泵 (t) This lookup table can represent the relationship between blood flow rate, drive speed, and at least one of the pressure difference between the blood outlet and the blood inlet, and the drive current supplied to the drive unit. Such a lookup table may include a set of characteristic curves describing the respective relationships, such as a set of curves, each representing a certain pump speed. It will be appreciated that other suitable lookup tables can be used, and the values ​​in the lookup table can be given in various units.

[0044] Data used for lookup tables, such as motor current and blood flow rate, can be recorded in the test bench assembly by running a blood pump in the fluid at a given motor speed and a defined pump load (pressure difference between inlet and outlet) while simultaneously recording the flow rate generated by the pump. The pump load can be increased over time, for example, from zero load (no pressure difference between blood inlet and outlet, i.e., maximum flow rate) to maximum load (no pump function, i.e., no flow rate), while recording both motor current and blood flow rate. Such lookup tables can be created for several different motor speeds. These lookup tables are used to determine blood flow rate. Q 泵 (t) It can provide a method for determining blood flow during blood pump operation. Q 泵 (t) Advantageous methods, especially for measuring or calculating blood flow. Q 泵 (t) In comparison, using a lookup table, blood flow... Q 泵 (t) The determination is based solely on the readily available operating parameters of the blood pump. Therefore, sensors for detecting patient parameters, such as pressure sensors or flow sensors used to detect pressure differences within the patient's blood vessels, are unnecessary. Furthermore, blood flow is read from a lookup table. Q 泵 (t) The value does not require computationally intensive calculations.

[0045] However, by simply applying zero-flow control mode within a single cardiac cycle to monitor one or more appropriate characteristic cardiac parameters, the heart may not be able to adequately adapt to the loss of pumping assistance. Therefore, the monitored characteristic cardiac parameters may still be insufficient to indicate the true state of cardiac recovery, such as the heart's actual pumping capacity. Thus, the zero-flow control mode applied within a single cardiac cycle can be repeated over several consecutive cardiac cycles.

[0046] Therefore, the predetermined zero-flow period can be set to last for at least one complete cardiac cycle or a predetermined number of complete, continuous cardiac cycles. For example, the predetermined zero-flow period can be set to a segment of a cardiac cycle up to several hours. In this way, the heart can fully adapt to a state of zero-assistance to the blood pump, thereby allowing for a better determination of the actual state of cardiac recovery.

[0047] Zero flow can also be combined within a single heartbeat and over a complete cardiac cycle. For example, zero flow control mode can be applied initially for relatively short periods, such as within segments of 1 to 300 consecutive cardiac cycles. After confirming natural cardiac function and adequate recovery, zero flow control mode can be applied for longer periods, such as over complete cardiac cycles of minutes or hours up to days.

[0048] The second aspect provides a system including an intravascular blood pump for assisting the heart and a control device according to the first aspect.

[0049] Preferably, the blood pump is catheter-based, that is, the blood pump preferably includes a catheter and a pump unit, and preferably, the pump unit is located at the distal end of the catheter.

[0050] Preferably, the blood pump can be implemented as a rotary blood pump, i.e., a blood pump driven by a rotary motor.

[0051] Blood pumps can be catheter-based for direct percutaneous implantation or placement into the heart via a corresponding blood vessel. For example, a blood pump can be as disclosed, for instance, in US5911685, specifically arranged for temporary placement or implantation into a patient's left or right heart. As mentioned above, the present invention is particularly applicable to intravascular blood pumps, and less relevant to larger VADs not placed inside a blood vessel or heart but located outside the patient's heart, such as those implanted in the chest cavity.

[0052] Preferably, the blood pump is a low-inertia device. (a) The blood pump is a low-inertia device including one or more of the following characteristics; (b) the moving parts of the blood pump, particularly the rotating parts, such as rotors or impellers, are made of lightweight materials, such as plastics, thus having low mass; (c) the drive unit, such as an electric motor, is arranged close, preferably very close, and most preferably adjacent to the moving parts of the pump unit driven by the drive unit, such as rotors or impellers; (d) if the blood pump is based on a conduit, it does not have rotating drive cables or drive lines; (e) the coupling or connection, such as a shaft, between the drive unit and the rotating parts of the pump unit driven by the drive unit, such as rotors or impellers, is short; and (f) all moving parts of the blood pump, particularly the rotating parts, have small diameters.

[0053] Low-inertia devices specifically include intravascular blood pumps for percutaneous insertion into a patient's blood vessels. Because of their small diameter, especially compared to relatively large VADs, all moving parts of the intravascular blood pump are lightweight and located close to the axis of rotation. This allows for very precise pump speed control, as the impeller's rotation is only slightly affected by its inertia. This means that only a slight delay occurs between the command signal and the actual response of the blood pump. Conversely, a VAD designed, for example, as a centrifugal blood pump, may be bulky and likely have a large diameter and therefore a large rotor with significant mass, and cannot be described as a "low-inertia device."

[0054] One characteristic of low-inertia devices is that, for example, reducing the pump speed of a low-inertia device, especially rapidly, does not require a negative speed signal (which is often necessary in large VADs) or other braking commands. Instead, reducing the motor current directly results in a decrease in pump speed, and the blood pump can be put into zero-flow control mode simply by reducing the motor current. This is particularly important for control within a single heartbeat because the cardiac cycle is very short and requires a short response time from the moving part of the blood pump. Conversely, it is also desirable to rapidly accelerate the moving part, i.e., rapidly increase the pump speed, to terminate the zero-flow control mode.

[0055] For example, using the low-inertia device of the present invention, the pump speed can be significantly increased or decreased within a very short time period, for example, within about 50 ms to about 100 ms, preferably within 60 ms to 80 ms. In other words, the pump speed can change rapidly or can undergo a "step change".

[0056] For example, during the stated time period, the pump rate may decrease from approximately 35,000 rpm to approximately 10,000 rpm, or in another blood pump from approximately 51,000 rpm to approximately 25,000 rpm, or vice versa, with a corresponding increase. However, the duration of the pump rate change also depends on other factors, such as blood flow, pressure gradient, the amount of the intended pump rate change (i.e., the difference between the intended pump rate and the rate before and after the change), or the time point within the cardiac cycle (because blood flow accelerates during cardiac systole and slows during cardiac diastole).

[0057] The third aspect provides a method for controlling blood flow in an intravascular blood pump as discussed in the first aspect. Q 泵 (t) The method involves a blood pump comprising a pump unit and a drive unit, wherein the pump unit is configured to deliver blood from a blood inlet toward a blood outlet. The method includes the following steps: (i) comparing a set blood flow rate value in a first closed-loop cycle. Q 泵 设定 (t) Blood flow value Q 泵 (t) Obtain control error e(t) (ii) Due to control error e(t) Determine the set speed value of the drive unit n 泵 设定 (t) By comparing the set speed value in the second closed-loop cycle. n 泵 设定 (t) With drive speed n 泵 (t) To control the drive speed of the drive unit n 泵 (t) .

[0058] Preferably, the method further includes the step of: providing a zero-flow mode, in which a blood flow value is set. Q 泵 设定 (t) The flow rate is zero during a predetermined zero-flow control period, and preferably the predetermined zero-flow control period is set as a segment of a cardiac cycle of a continuously assisted heart, or a segment and / or a complete cardiac cycle lasting at least one complete cardiac cycle or a predetermined number of consecutive cardiac cycles.

[0059] As described in more detail above regarding the control device, the method may include using an appropriate lookup table to determine or estimate blood flow. Q 泵 (t) The steps.

[0060] Preferably, the first closed-loop cycle is the outer control loop of the cascaded control, and the second closed-loop cycle is the inner control loop of the cascaded control. The cascaded control system including the outer and inner control loops has been described in more detail above regarding the control device, and is also effective for this method.

[0061] Preferably, the method further includes synchronizing the zero-flow control period with at least one specific characteristic cardiac cycle event.

[0062] Preferably, the start and / or end of the zero-flow control period is synchronized with the occurrence of the at least one characteristic cardiac cycle event.

[0063] Preferably, the method further includes monitoring one or more values ​​of characteristic cardiac parameters.

[0064] Preferably, the method further includes identifying trends in one or more values ​​of the monitored characteristic cardiac parameters.

[0065] The fourth aspect provides a control device according to the first aspect, configured to perform the method according to the third aspect.

[0066] The aforementioned functions or effects of the control device and the corresponding functions or effects of the control method can be implemented by a corresponding computing unit of the control device in hardware or software or any combination thereof. Such a computing unit can be configured by means of a corresponding computer program having software code for causing the computing unit to execute the corresponding desired control steps. Such programmable computing units are generally known in the art and to those skilled in the art. Therefore, it is not necessary to describe such programmable computing units in detail here. Furthermore, the computing unit may include specific dedicated hardware for a particular function, such as one or more signal processors for processing and / or analyzing, for example, the measurement signals discussed. In addition, the corresponding unit for controlling the drive speed of the blood pump can also be implemented by a corresponding software module.

[0067] The corresponding computer program can be stored on a data carrier containing the computer program. Alternatively, the computer program can be transmitted as a data stream that includes the computer program but does not require a data carrier, for example, via the Internet. Attached Figure Description

[0068] In the following text, the invention will be explained by way of example with reference to the accompanying drawings.

[0069] Figure 1A block diagram of feedback control is shown.

[0070] Figure 2 An exemplary blood pump is shown, which is placed through the aorta and extends through the aortic valve into the left ventricle, as well as a block diagram of a control device for the pumping speed of the blood pump.

[0071] Figure 3 Showing more details Figure 2 An exemplary blood pump.

[0072] Figure 4 It is a schematic diagram showing a set of characteristic curves representing the relationship between the actual pressure difference between the inlet and outlet of the blood pump, the actual pump speed of the blood pump, and the blood flow generated by the blood pump. Detailed Implementation

[0073] Figure 1 A block diagram is shown, which is an example of a feedback control loop for blood flow control implemented as a cascaded control system. The control loop includes an external controller 401 and an internal controller 402. The external controller 401 is embedded in the external control loop and controls the blood flow command signal by comparing it. Q 泵 设定 (t) With the blood flow generated Q 泵 (t) And through setting the setpoint of the internal control loop, namely the speed command signal of the blood pump 50. n 泵 设定 (t) To adjust, for example Figure 3 The blood flow generated by the blood pump 50 shown Q 泵 (t) The internal controller 402 is part of the internal control loop and adjusts the motor current accordingly. I 泵 (t) To control the speed of blood pump 50 n 泵 (t) .

[0074] exist Figure 1 The blood flow generated in the feedback loop shown Q 泵 (t) Exemplarily, by means of, representing, for example, current I 泵 (t) ,speed n 泵 (t) and the blood flow generated Q泵 (t) The relationship is calculated using a lookup table. Alternatively or additionally, another lookup table can be used to represent the pressure difference between the blood pump outlet and the blood pump inlet (see reference). Figure 3 ),speed n 泵 (t) and blood flow Q 泵 (t) The relationship. The blood flow generated. Q 泵 (t) Another alternative or additional option for data acquisition is to use a flow sensor.

[0075] Flow control is based on blood flow command signals Q 泵 设定 (t) Regulate blood flow through blood pump 50 Q 泵 (t) Blood flow command signal Q 泵 设定 (t) It can be a constant value (also called a setpoint) or a signal that changes over time. A constant blood flow setpoint. Q 泵 设定 (t) The blood flow rate can be in the range of [-5…10] L / min, preferably in the range of [0…5] L / min, and most preferably 0 L / min or extremely low as zero flow.

[0076] One purpose of the flow control disclosed herein is to monitor the values ​​of characteristic parameters of the heart using an implanted pump to determine the heart's recovery status while minimizing the pump's impact on cardiac function. For this purpose, the flow control can use a set blood flow rate of 0 L / min. Q 泵 设定 (t) Or extremely low blood flow as zero flow.

[0077] It has been found that the inner control loop can have a smaller time constant compared to the outer control loop. This allows the inner control loop to respond faster than the outer control loop. Furthermore, the inner control loop can be executed at a higher sampling rate than the outer control loop.

[0078] For example, the sampling rate fs of the data in the internal control loop 内 It can be in the range of [250…10k]Hz, preferably in the range of [1…3]kHz, and most preferably 2.5kHz.

[0079] For example, the sampling rate fs of the data in the outer control loop 外 It can be in the range of [25…1000] Hz, preferably in the range of [100…300] Hz, and most preferably 250 Hz.

[0080] Figure 2 and Figure 3 An example of a blood pump is shown. The blood pump is an intravascular blood pump configured for percutaneous insertion into the heart. In the illustrated embodiment, the blood pump is a miniature axially rotating blood pump, hereinafter referred to as blood pump 50. Such a blood pump is known, for example, from US5911685A.

[0081] The blood pump 50 is based on the catheter 20, which can be temporarily guided into the ventricles of the patient's heart via a blood vessel. In addition to the catheter 20, the blood pump 50 includes a rotary drive unit 51 secured to the catheter 20. The rotary drive unit 51 is coupled to a pump unit 52 located at an axial distance therefrom.

[0082] The flow sleeve 53 is connected to the pump unit 52 at one end, extends from the pump unit 52, and has a blood inlet 54 at the other end. The blood inlet 54 has a soft and flexible end 55 attached thereto.

[0083] Pump unit 52 includes a pump housing with a blood outlet 56. Furthermore, pump unit 52 includes a drive shaft 57 protruding from drive unit 51 into the pump housing. Drive shaft 57 drives impeller 58 as a thrust element. During operation of blood pump 50, blood is drawn in through blood inlet 54, delivered through sleeve 53, and discharged through blood outlet 56. Blood flow is generated by means of the rotating impeller 58 driven by drive unit 51.

[0084] In the illustrated embodiment, three wires pass through the catheter 20: two signal lines 28A and 28B, and a power supply line 29 for supplying power to the drive unit 51 of the blood pump 50. The signal lines 28A and 28B and the power supply line 29 are attached to the control device 100 at their proximal ends. Figure 2 Signal lines 28A and 28B are associated with their respective blood pressure sensors, each having a corresponding sensor head 30 and 60. Power supply line 29 includes multiple supply lines for supplying power to the drive unit 51.

[0085] The drive unit 51 may be a synchronous motor. In an exemplary configuration, the motor may include several motor winding units for driving an impeller 58 coupled to the drive shaft 57. The rotor of the synchronous motor may include at least one field winding, or alternatively, a permanent magnet, in the case of a permanent magnet excitation synchronous motor.

[0086] In a preferred embodiment, the blood pump 50 is a catheter-based miniature axially rotating blood pump for percutaneous insertion into a patient's heart via a blood vessel. Here, "miniature" means small enough that the blood pump can be percutaneously inserted into the heart via a blood vessel that guides it, for example, into one of the ventricles of the heart. This also defines the blood pump 50 as an "intravascular" blood pump for percutaneous insertion. Here, "axial" means that the pump unit 52 and the drive unit 51 that drives it are arranged axially. Here, "rotary" means that the function of the pump is based on the rotational operation of a thrust element (i.e., impeller 58) driven by a rotary motor of the drive unit 51.

[0087] As discussed above, the blood pump 50 is based on the catheter 20, through which the blood pump 50 can be inserted into a blood vessel, and the power supply line 29 can pass through the catheter 20 to supply power to the drive unit 51 and to supply control signals, for example, from the drive unit 51 and the sensor heads 30, 60.

[0088] As mentioned above, the present invention is specifically configured for use in intravascular blood pumps, such as Figure 3 The blood pump 50 shown is less commonly configured or even unsuitable for implantation outside the patient's heart, such as centrifugal blood pumps that are connected to the patient's heart and placed in the chest cavity and operate within a range of pump speeds. As explained herein, this is specifically due to inertial effects, which significantly affect the function of large VADs but can be avoided in low-inertia devices such as intravascular blood pumps.

[0089] like Figure 2 As shown, each signal line 28A, 28B is connected to a corresponding blood pressure sensor with a corresponding sensor head 30, 60, which is externally located on the housing of the pump unit 52. The sensor head of the first pressure sensor is connected to signal line 28B and is used to measure blood pressure at the blood outlet 56. The sensor head of the second blood pressure sensor is connected to signal line 28A and is used to measure blood pressure at the blood inlet 54. Basically, the signal captured by the pressure sensor carries information about the pressure at the sensor location and can have any suitable physical source, such as optical, hydraulic, or electrical sources, which is transmitted via the corresponding signal lines 28A, 28B to the corresponding input section of the data processing unit 110 of the control device 100. Figure 2 In the example shown, the blood pump 50 is positioned in the aorta and via the aortic valve in the left ventricle of the heart, such that pressure sensors are arranged to measure aortic pressure AoP(t) via sensor head 60 and left ventricular pressure LVP(t) via sensor head 30.

[0090] Data processing unit 110 is configured to acquire external and internal signals for signal processing, including, for example, calculating the difference between pressure signals as a means of estimating the resulting blood flow. Q 泵 (t) The basis of this can be used as a control signal for flow control methods, for signal analysis to detect the occurrence of characteristic events during the cardiac cycle based on the acquired and calculated signals, and for generating a trigger signal σ(t) to trigger the velocity command signal generator 120, to name just a few.

[0091] For a given example of a flow control method, speed command signal generator 120 represents Figure 1 External controller 401.

[0092] In the illustrated embodiment, the data processing unit 110 is connected to an additional measuring device, generally described as 300, via corresponding signal lines. In this embodiment, such an additional measuring device is the patient monitoring unit 310 and the electrocardiograph (ECG) 320; obviously, these two devices 310 and 320 are merely two examples and not exhaustive, i.e., other measuring devices may also be used to provide useful signals. The described ECG 320 provides the ECG signal ECG(t) to the data processing unit 110.

[0093] The control device 100 also includes a user interface 200. The user interface 200 is used for user interaction with the device. The user interface 200 includes a display 210 as an output device and a communication interface 220 as an input device. The display 210 displays the values ​​of set parameters, the values ​​of monitored parameters, such as measured pressure signals, and other information. Furthermore, through the communication interface 220, the user of the control device 100 can control the control device 100, for example, by changing the settings and parameters of the entire system, including the blood pump and the control device 100.

[0094] For a given example of a flow control method, one setting would be Figure 1 Expected pump flow rate Q 泵 设定 (t) The choice.

[0095] The data processing unit 110 is specifically configured to acquire or predict the occurrence time of one or more predefined characteristic events of the assisted heart during the cardiac cycle. For example, the data processing unit 110 is configured to detect predefined characteristic cardiac cycle events during the cardiac cycle by means of real-time analysis of the monitored signal. Alternatively or additionally, predefined characteristic cardiac cycle events, such as, for example, R waves, can be identified by ECG signals from ECG 320.

[0096] The occurrence of one or more defined characteristic events is used to generate a specific trigger signal σ(t) or a sequence of trigger signals σ(t). The resulting trigger signal σ(t) (or its sequence) is sent to the speed command signal generator 120 to accordingly trigger a change in the speed command signal provided to the speed control unit 130.

[0097] In the context of this invention, the speed command signal generator 120 is configured to operate the blood pump 50 in a zero-flow control mode.

[0098] The data processing unit 110 can be configured to predict the timing of the at least one predefined characteristic cardiac cycle event in an upcoming cardiac cycle based on stored information about characteristic cardiac cycle events during the current and / or previous cardiac cycles, and also analyze these velocity command signals. n 泵 设定 (t) The previous value.

[0099] For example, a characteristic cardiac cycle event could be the onset of cardiac contraction at the beginning of cardiac systole. The detection or prediction of such a characteristic cardiac cycle event can be used to synchronize the sequential application of a specific control method for the blood pump 50 within one or more cardiac cycles or within specific time intervals of the cardiac cycle.

[0100] Accordingly, the speed command signal generator 120 is configured to respond to a given blood flow command signal that can be set to, for example, 0 L / min. Q 泵 设定 (t) To adjust the speed command signal for blood pump 50 n 泵 设定 (t) To control the blood flow generated Q 泵 (t) .

[0101] In order to control the blood flow generated Q 泵 (t)The speed command signal generator 120 is configured as an external controller in a cascaded control system to continuously control the generated blood flow in a time-continuous manner. Q 泵 (t) (As a first setting) or by using an event-based switching control method (as a second setting) to provide a suitable speed command signal to the speed control unit 130. n 泵 设定 (t) .

[0102] In the first setup, the command signal generator 120 continuously provides speed command signals to the speed control unit 130. n 泵 设定 (t) The speed control unit 130, as part of the cascaded blood flow control system, is fed external and internal signals by the data processing unit 110.

[0103] In the second setting, the speed command signal generator 120 operates as in the first setting, with the additional feature of turning continuous blood flow control on and off.

[0104] In zero-flow control mode, the speed command signal n 泵 设定 (t) The flow controller in the external control loop is continuously adjusted. The on / off switching is triggered by at least one trigger signal σ(t) provided by the data processing unit 110.

[0105] If zero-flow control is applied only to short time intervals, particularly short intervals compared to the duration of a cardiac cycle, then the second setting is appropriate; in other words, the generated blood flow is commanded by a blood flow command signal of 0 L / min only during brief time intervals within the cardiac cycle. Q 泵 设定 (t) To control (blood flow control within a single beat).

[0106] Speed ​​control unit 130 according to speed command signal n 泵 设定 (t) Current is transmitted via power supply line 29 I 泵 (t) The drive unit 51, which supplies power to the blood pump 50, controls the speed of the blood pump 50. n 泵 (t) .

[0107] Supply of motor current I 泵 (t) The current level corresponds to, for example, the current currently required by the motor of drive unit 51, to establish a current level as indicated by the speed command signal. n 泵 设定 (t) Defined target speed level. Such as the supplied motor current. I 泵 (t) The measured signal can be used as a representative signal of the internal signals of the control device 100 and can be provided to the data processing unit 110 for further processing. The blood pump 50 can also communicate with the control unit via the power supply line 29.

[0108] Basically, among other things, the control device 100 is configured to operate the blood pump 50 in a selectable zero-flow control mode, in which the blood flow rate of the blood pump 50 is... Q 泵 (t) The pressure difference is controlled to counteract the changes in blood flow outlet 56 and blood flow inlet 54 caused by the heartbeat, which can be considered a disturbance. Blood flow rate Q 泵 (t) By adjusting the speed command signal n 泵 设定 (t) To control. As presented herein, the control device 100 is configured to control the blood flow of the blood pump 50. Q 泵 (t) This allows the blood pump 50 to generate zero blood flow during a predetermined zero flow control period.

[0109] In the first setting using continuous flow control, a predetermined zero-flow control period is set to last for at least one complete cardiac cycle or a predetermined number of complete, continuous cardiac cycles. Furthermore, in the first setting, the control device 100 is configured to monitor the values ​​of one or more characteristic cardiac parameters using the implanted blood pump 50. Similarly, the monitored values ​​of one or more characteristic cardiac parameters can be used as indicators of the state of cardiac recovery.

[0110] In the second setting using event-based zero-flow control, the predetermined zero-flow control period is set as a segment of the duration of a cardiac cycle of a heart with the implanted blood pump 50. In this setting, the control device 100 is configured to synchronize the start and end of the zero-flow control period with the occurrence of specific characteristic cardiac cycle events.

[0111] It is worth noting that the control device 100 can periodically or randomly control the blood flow through the blood pump 50. Q 泵 (t) .

[0112] In practice, a characteristic cardiac cycle event is the opening or closing of the aortic valve or the opening or closing of the mitral valve, or a specific pressure value such as end-diastolic left ventricular pressure.

[0113] Furthermore, in the second setting, as in the first setting, the control device 100 is configured to monitor the values ​​of one or more characteristic cardiac parameters of the heart with the implanted blood pump 50 during a zero-flow control period. The values ​​of the monitored one or more characteristic cardiac parameters can also be used as indicators of the state of cardiac recovery.

[0114] The control device is also configured to identify trends in the values ​​of one or more monitored characteristic parameters. As mentioned above, this trend can also be interpreted as an indicator of the state of cardiac recovery.

[0115] In any case, in order to execute the zero-flow control mode, the control device 100 is configured to adjust the speed command signal of the blood pump 50. n 泵 设定 (t) To control blood flow Q 泵 (t) This drives the speed n 泵 (t) During the cardiac cycle, the blood pressure difference between the blood outlet 56 and the blood inlet 54 of the blood pump 50 is affected.

[0116] Specifically, the control device 100 is configured to determine the blood flow rate of the blood pump 50 based on a predetermined signal. Q 泵 (t)， Predetermined signals, such as drive speed n 泵 (t) Current I 泵 (t) And / or the pressure difference between the blood outlet 56 and the blood inlet 54 of the blood pump 50.

[0117] Figure 4 This is an exemplary schematic diagram showing a set of characteristic curves, which represent the pressure difference between the blood outlet 56 and the blood inlet 54 of the blood pump 50. ΔP 泵 (t) Blood pump 50 drive speedn 泵 (t) And produced by blood pump 50, for example, through Figure 3 Blood flow in the flow cannula 53 Q 泵 (t) The relationship between them.

[0118] To perform zero-flow control, the data processing unit 110 is configured to operate based on a known speed. n 泵 (t) The known current supplied to the pump unit I 泵 (t) and / or the pressure difference between the blood outlet 56 and the blood inlet 54 of the monitored blood pump 50. ΔP 泵 (t) To continuously determine the blood flow generated by blood pump 50. Q 泵 (t) The set blood flow value Q 泵 设定 (t) It can be a positive value, either zero or at least close to zero.

[0119] For example, based on Figure 4 In this situation, the pressure difference between the blood outlet 56 and the blood inlet 54 of the monitored blood pump 50 ΔP 泵 (t) 60 mmHg, drive speed n 泵 (t) A blood flow of approximately 0 L / min must be generated at approximately 20,000 L / min (rpm). Q 泵 (t) .

[0120] Will realize, Figure 4 The values, relationships, and shapes of the curves shown in the characteristic graph are merely illustrative and can vary depending on the blood pump used, the patient, or other factors. Specifically, each blood pump, even those of the same type, can have their own characteristic graph; that is, the lookup table can be pump-specific. Moreover, once implanted in a patient, the characteristic graph may need to be adapted using patient-specific correction factors, including factors such as blood viscosity and pump location. Using correction factors can increase the accuracy of the flow estimates obtained from the lookup table.

[0121] As discussed earlier, the current pressure differential... ΔP泵 (t) The pressure sensor of the blood pump 50 can be used as an aid (e.g., Figure 3 The speed is determined by sensors 30 and 60. Therefore, the speed control unit 130 can continuously provide values ​​other than those stored in the storage unit, such as stored values. Figure 4 The characteristic curve (representing the above values) ΔP 泵 (t) , Q 泵 (t) and n 泵 (t) A lookup table showing the relationships between data processing units. The storage unit may be a read-only memory of the data processing unit 110, or alternatively a storage chip in the blood pump 50 or its control console.

[0122] At least one characteristic cardiac parameter value is at least one of the following: arterial blood pressure measured each time a zero-flow operating mode is established.

[0123] Preferably, the blood pump 50 is a low-inertia device. This is specifically achieved by the fact that the moving parts of the blood pump 50, particularly the rotating parts, such as the rotor or impeller, are made of lightweight materials, such as plastic, thus having low mass. Furthermore, the drive unit, such as an electric motor, is arranged close, preferably very close, and most preferably adjacent to the parts driven by the drive unit, such as the thrust element, such as the rotor or impeller 58. Additionally, even though the blood pump 50 is based on a catheter, it does not have a rotating drive cable or drive line. Furthermore, the coupling or connection between the drive unit 51 and the thrust element driven by the drive unit 51, such as the rotor or impeller 58, such as the shaft 57, remains short. Additionally, all moving parts of the blood pump 50, particularly the rotating parts, have small diameters.

[0124] In summary, in the zero-flow control method proposed in this paper, the control device 100 controls the blood flow generated by the blood pump 50 through a cascaded control consisting of an outer control loop and an inner control loop. Q 泵 (t) This means the blood flow generated by the blood pump 50 Q 泵 (t) The speed command signal for the drive unit 51 of the blood pump 50 is adjusted in the external control loop. n 泵 设定 (t) To control and drive speed n 泵 (t) By adjusting the current in the internal control loop I泵 (t) Zero-flow control can be applied continuously or partially continuously, meaning the zero-flow control period lasts for one or more complete cardiac cycles or only a segment of a cardiac cycle. In cases where the predetermined zero-flow control period lasts only a portion of the duration of a cardiac cycle, the zero-flow control period can be synchronized with the heartbeat by means of at least one characteristic event of the cardiac cycle.

Claims

1. A control device (100) for controlling the blood flow rate of a blood pump (50). Q 泵 (t) The blood pump (50) is configured to deliver blood from the blood inlet (54) toward the blood outlet (56), wherein The control device (100) is configured to operate the blood pump (50) in a selectable zero-flow control mode, wherein a blood flow command signal between 0 and 1 L / min is provided. Q 泵 设定 (t) Selected, and the control device includes a first controller (401) and a second controller (402), wherein The first controller (401) is configured to adjust the speed command signal for the drive unit (51). n 泵 设定 (t)， The blood flow is controlled within a predetermined zero-flow control period. Q 泵 (t) And the second controller (402) is configured to respond to the speed command signal. n 泵 设定 (t) Control the driving speed of the drive unit (51) n 泵 (t) ,in The control device (100) is configured to set the predetermined zero-flow control period as a complete cardiac cycle or a segment of such cardiac cycle for a continuously assisted heart, and to synchronize the start and / or end of the zero-flow control period with the occurrence of at least one characteristic cardiac cycle event.

2. A control device (100) for controlling the blood flow rate of a blood pump (50). Q 泵 (t) The blood pump (50) is configured to deliver blood from the blood inlet (54) toward the blood outlet (56), wherein The control device (100) is configured to operate the blood pump (50) in a selectable zero-flow control mode, wherein a blood flow command signal between 0 and 1 L / min is provided. Q 泵 设定 (t) Selected, and the control device includes a first controller (401) and a second controller (402), wherein The first controller (401) is configured to adjust the speed command signal for the drive unit (51). n 泵 设定 (t) To control the blood flow Q 泵 (t) The second controller (402) is configured to respond to the speed command signal. n 泵 设定 (t) Control the driving speed of the drive unit (51) n 泵 (t) ,in The zero-flow control mode is first applied within segments of cardiac cycles in a series of 1 to 300 consecutive cardiac cycles, and then applied within complete cardiac cycles of several minutes, hours, or days.

3. The control device (100) according to claim 1 or 2, wherein the first controller (401) is further configured to base on the blood flow command signal. Q 泵 设定 (t) With the blood flow Q 泵 (t) The difference ΔQ between them is used to determine the speed command signal. n 泵 设定 (t) .

4. The control device (100) according to claim 1 or 2, wherein the second controller (402) is configured to adjust the drive current supplied to the drive unit (51). I 泵 (t) To control the drive speed n 泵 (t) .

5. The control device (100) according to claim 1 or 2, wherein the first controller (401) and the second controller (402) are part of a cascaded control system, wherein the first controller (401) is an external controller and the second controller (402) is an internal controller.

6. The control device (100) according to claim 1, wherein the at least one characteristic cardiac cycle event is the opening of the aortic valve.

7. The control device (100) according to claim 1, wherein the at least one characteristic cardiac cycle event is the closure of the aortic valve.

8. The control device (100) according to claim 1 or 2, wherein the control device (100) is configured to monitor the values ​​of one or more characteristic cardiac parameters.

9. The control device (100) according to claim 1 or 2, wherein the control device (100) is configured to periodically or randomly operate the blood pump (50) in the zero flow control mode.

10. The control device (100) according to claim 8, wherein the control device (100) is configured to identify a trend of one or more monitored values ​​of one or more monitored characteristic cardiac parameters.

11. The control device (100) according to claim 10, wherein the one or more characteristic cardiac parameters are at least one of the following: arterial pressure pulsatility (AOP)| 最大 -AOP| 最小 Mean arterial pressure, cardiac contractility dLVP(t) / dt | 最大 diastolic function of the heart dLVP(t) / dt| 最小 Heart rate (HR).

12. The control device (100) according to claim 1 or 2, wherein the control device (100) is configured to measure the blood flow by means of a sensor. Q 泵 (t) Or calculate or estimate the blood flow. Q 泵 (t) .

13. The control device (100) according to claim 1 or 2, wherein the control device (100) is configured to use a representation of the blood flow rate. Q 泵 (t) The driving speed n 泵 (t) and the pressure difference Δ between the blood outlet (56) and the blood inlet (54). P 泵 (t) and the drive current supplied to the drive unit (51) I 泵 (t) A lookup table of relationships between at least one of the blood flow rates is used to determine the blood flow rate. Q 泵 (t) .

14. A system comprising an intravascular blood pump (50) for percutaneous insertion into a patient's blood vessel and a control device (100) according to claim 1 or 2.

15. The system of claim 14, wherein the blood pump (50) is a low-inertia device by including one or more of the following characteristics: the moving or rotating parts of the blood pump are made of lightweight material and thus have low mass; the drive unit (51) is arranged close to or adjacent to the moving parts driven by the drive unit (51); the coupling or connection between the drive unit (51) and the rotating parts driven by the drive unit (51) is short; and all moving or rotating parts of the blood pump have small diameters.

16. The system according to claim 15, wherein at least one of the moving or rotating portion and the moving portion driven by the drive unit (51) is a rotor or an impeller.

17. The system of claim 15, wherein the lightweight material is plastic.

18. The system according to claim 15, wherein the drive unit (51) is an electric motor.

19. The system of claim 15, wherein the drive unit (51), if based on a conduit, does not have a rotating drive cable or drive line.

20. The system according to claim 15, wherein the coupling part or connecting part is a shaft.

21. A control device for controlling the blood flow rate of a blood pump (50). Q 泵 (t) The control device is configured to: The set blood flow value is compared in the first closed-loop cycle. Q 泵 设定 (t) Blood flow value Q 泵 (t) Obtain control error e (t) , Due to the control error e(t) Determine the set speed value of the drive unit n 泵 设定 (t) , By comparing the set speed value in the second closed-loop cycle n 泵 设定 (t) Drive speed of drive unit (51) n 泵 (t) To control the drive speed n 泵 (t) ,as well as A zero-flow mode is provided, in which the set blood flow value is provided. Q 泵 设定 (t) The flow rate is zero or between 0 L / min and 1 L / min during a predetermined zero-flow control period, wherein the start and / or end of the zero-flow control period is synchronized with the occurrence of at least one characteristic cardiac cycle event.

22. A control device for controlling the blood flow rate of a blood pump (50). Q 泵 (t) The control device is configured to: The set blood flow value is compared in the first closed-loop cycle. Q 泵 设定 (t) Blood flow value Q 泵 (t) Obtain control error e (t) , Due to the control error e(t) Determine the set speed value of the drive unit n 泵 设定 (t) , By comparing the set speed value in the second closed-loop cycle n 泵 设定 (t) Drive speed of drive unit (51) n 泵 (t) To control the drive speed n 泵 (t) , A zero-flow mode is provided, in which the set blood flow value is provided. Q 泵 设定 (t) The flow rate is zero or between 0 L / min and 1 L / min, wherein the zero flow control mode is first applied within segments of cardiac cycles in 1 to 300 consecutive cardiac cycles, and then applied within complete cardiac cycles of several minutes, hours or days.

23. The control device according to claim 21 is further configured to set the predetermined zero-flow control period as a segment of a cardiac cycle of a continuously assisted heart, or a segment and / or a complete cardiac cycle of at least one complete cardiac cycle or a predetermined number of consecutive cardiac cycles.

24. The control device according to claim 21 or 22, wherein the first closed-loop cycle is an outer control loop of cascaded control, and the second closed-loop cycle is an inner control loop of cascaded control.

25. The control device of claim 22 is further configured to synchronize a predetermined zero-flow control period of the zero-flow control mode with at least one characteristic cardiac cycle event.

26. The control device of claim 25 is further configured to synchronize the start and / or end of the zero-flow control period with the occurrence of at least one characteristic cardiac cycle event.

27. The control device according to claim 21 or 22 is further configured to monitor one or more values ​​of characteristic cardiac parameters.

28. The control device of claim 27 is further configured to identify trends in one or more values ​​of the monitored characteristic cardiac parameters.

29. A control device for controlling the blood flow of an intravascular blood pump (50) percutaneously inserted into a patient's blood vessel. Q 泵 (t) The blood pump (50) includes a pump unit (52) and a drive unit (51), and the pump unit is configured to deliver blood from a blood inlet (54) toward a blood outlet (56), wherein the control device is configured to: The set blood flow value is compared in the first closed-loop cycle. Q 泵 设定 (t) Blood flow value Q 泵 (t) Obtain control error e (t) , Due to the control error e(t) Determine the set speed value of the drive unit n 泵 设定 (t) , By comparing the set speed value in the second closed-loop cycle n 泵 设定 (t) Drive speed of the drive unit (51) n 泵 (t) To control the drive speed n 泵 (t), in, The control device includes a data processing unit (110) connected via corresponding signal lines to an additional measuring device for providing signals, the additional measuring device including a patient monitoring unit (310) and an electrocardiograph (320).

30. The control device according to claim 29, wherein, The control device further includes a speed command signal generator (120), and the data processing unit (110) is used to generate a trigger signal σ(t) to trigger the speed command signal generator (120).

31. The control device according to claim 29, wherein, The blood pump (50) also includes a catheter (20), to which the drive unit (51) is fastened, and signal lines (28A, 28B) and a power supply line (29) pass through the catheter (20) and are attached to the control device (100) at their proximal ends, wherein the signal lines (28A, 28B) are associated with respective blood pressure sensors having sensor heads (30, 60), and the power supply line (29) is used to supply power to the drive unit (51).

32. The control device according to claim 31, wherein, The blood pressure sensor includes a first blood pressure sensor and a second blood pressure sensor. The sensor head (60) of the first blood pressure sensor is connected to a signal line (28B) and is used to measure the blood pressure at the blood outlet (56). The sensor head (30) of the second blood pressure sensor is connected to another signal line (28A) and is used to measure the blood pressure at the blood inlet (54).

33. The control device according to any one of claims 29 to 32, wherein, The blood pump (50) also includes a flow sleeve (53) which is connected at one end to the pump unit (52), extends from the pump unit (52), and has the blood inlet (54) at the other end.

34. The control device according to any one of claims 29 to 32, wherein, The pump unit (52) includes a pump housing having the blood outlet (56) and a drive shaft (57) protruding from the drive unit (51) into the pump housing of the pump unit (52), the drive shaft (57) driving an impeller (58) as a thrust element to generate blood flow.

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