Method and device for detecting abnormalities in a ventricular assist device

Abstract

The application provides an abnormality detection method and device of a ventricular assist device. The method comprises the following steps: acquiring a first pumping flow and a second pumping flow, the first pumping flow being a maximum pumping flow of the ventricular assist device in a first cycle when the ventricular assist device operates at a target rotating speed, and the second pumping flow being a minimum pumping flow of the ventricular assist device in the first cycle when the ventricular assist device operates at the target rotating speed; calculating a target value, the target value being a ratio of a target flow difference to a first average flow, and the target flow difference being a difference between the first pumping flow and the second pumping flow; and judging whether the ventricular assist device is abnormal according to the first pumping flow, the second pumping flow and the target value. The application can monitor the operation of the ventricular assist device in real time through the auxiliary and fluctuation of the pumping flow of the ventricular assist device in a cardiac cycle, improve the accuracy of the abnormality detection of the operation of the ventricular assist device, and improve the pumping efficiency of the ventricular assist device.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a method and apparatus for detecting abnormalities in a ventricular assist device. Background Technology

[0002] Transcutaneous circulatory support devices or blood pumps can provide short-term support for up to several weeks for patients with impaired cardiac function or output. Some of these devices, particularly ventricular assist devices (VAPs), currently operate at a constant, pre-set speed. However, because users' output needs vary depending on their condition, the pumping flow rate of the VAP may not match the user's current needs. This mismatch can lead to abnormalities that reduce the performance of the VAP and, in severe cases, even damage the patient's heart. Therefore, how to monitor VAP abnormalities in real time during operation is a pressing issue. Summary of the Invention

[0003] This application provides a method and apparatus for detecting abnormalities in a ventricular assist device, which can monitor whether the ventricular assist device is malfunctioning in real time based on its pumping flow rate, thereby improving the pumping efficiency of the ventricular assist device.

[0004] In a first aspect, embodiments of this application provide a method for detecting abnormalities in a ventricular assist device, the method comprising:

[0005] A first pumping flow rate and a second pumping flow rate are obtained. The first pumping flow rate is the maximum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The second pumping flow rate is the minimum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The first cycle is the time interval between adjacent first pumping flow rates or second pumping flow rates.

[0006] Calculate a target value, the target value being the ratio of a target flow difference to a first average flow, the target flow difference being the difference between the first pumping flow and the second pumping flow, and the first average flow being the average pumping flow of the ventricular assist device during the first cycle;

[0007] The ventricular assist device is determined to be malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value.

[0008] Secondly, the present application provides a control unit for a ventricular assist device, the control unit comprising one or more processors, the one or more processors being used for:

[0009] A first pumping flow rate and a second pumping flow rate are obtained. The first pumping flow rate is the maximum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The second pumping flow rate is the minimum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The first cycle is the time interval between adjacent first pumping flow rates or second pumping flow rates.

[0010] Calculate a target value, the target value being the ratio of a target flow difference to a first average flow, the target flow difference being the difference between the first pumping flow and the second pumping flow, and the first average flow being the average pumping flow of the ventricular assist device during the first cycle;

[0011] The ventricular assist device is determined to be malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value.

[0012] Thirdly, embodiments of this application provide a ventricular assist device, the ventricular assist device comprising:

[0013] case;

[0014] An impeller disposed within the housing;

[0015] A control unit for controlling the rotation of the impeller, the control unit being used to perform the steps in the method described in the first aspect above.

[0016] Fourthly, embodiments of this application provide a medical device, the medical device including a processor, a memory, a communication interface, and one or more programs, the one or more programs being stored in the memory and configured to be executed by the processor, the programs including instructions for performing some or all of the steps described in the method described in the first aspect above.

[0017] Fifthly, embodiments of this application provide a computer-readable storage medium storing a computer program for electronic data interchange, wherein the computer program causes a computer to perform some or all of the steps described in the method described in the first aspect above.

[0018] Sixthly, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, the computer program being operable to cause a computer to perform some or all of the steps described in the method described in the first aspect of embodiments of this application. The computer program product may be a software installation package.

[0019] The technical solution provided in this application obtains a first pumping flow rate and a second pumping flow rate. The first pumping flow rate is the maximum pumping flow rate of the ventricular assist device (VAD) during a first cycle when it operates at a target speed. The second pumping flow rate is the minimum pumping flow rate of the VAD during the first cycle when it operates at the target speed. The first cycle is the time interval between adjacent first or second pumping flow rates. A target value is calculated, which is the ratio of the target flow rate difference to the first average flow rate. The target flow rate difference is the difference between the first and second pumping flow rates. The first average flow rate is the average pumping flow rate of the VAD during the first cycle. The VAD is then used to determine whether it is malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value. This application monitors the operation of the VAD in real time by observing the assistance and fluctuation of its pumping flow rate during the cardiac cycle, improving the accuracy of detecting abnormalities in the VAD's operation and thus improving the pumping efficiency of the VAD. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a ventricular assist device provided in an embodiment of this application;

[0022] Figure 2 This is a schematic diagram of a ventricular assist device provided in an embodiment of this application, located in the normal position of a patient's heart;

[0023] Figure 3 This is a flowchart illustrating an abnormality detection method for a ventricular assist device provided in an embodiment of this application;

[0024] Figure 4 This is a schematic diagram of the pumping flow rate of a ventricular assist device provided in an embodiment of this application;

[0025] Figure 5 This is a schematic diagram of the structure of a medical device provided in an embodiment of this application. Detailed Implementation

[0026] To help those skilled in the art better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the description of the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, software, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units not listed, or other steps or units inherent to such processes, methods, products, or apparatus.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] The medical devices and pumps involved in this application may be ventricular assist devices (VADs), such as implantable ventricular assist devices, interventional ventricular assist devices, etc.; the ventricular assist device may include at least one blood pump, wherein the blood pump may be a centrifugal pump, axial flow pump, magnetic levitation pump, etc.

[0030] In this application, "current" refers to the current driving a motor or electric motor, which, under constant supply voltage, is related to the power of the motor or electric motor. "Rotation speed" refers to the rotational speed of the motor or electric motor, which is related to the rotational speed of the rotor or impeller of the ventricular assist device and can be defined as rotational speed per minute. "Flow rate," "fluid flow rate," and "pump flow rate" refer to the volume of fluid delivered per unit time through the ventricular assist device, which can be estimated and measured in liters per minute.

[0031] It should be noted that in this application, the terms "proximal" or "proximal" refer to the end or side closer to the surgeon; and "distal" or "distal" refer to the end or side farther from the surgeon.

[0032] Please see Figures 1-2 , Figure 1This is a schematic diagram of the structure of a ventricular assist device 100 provided in an embodiment of this application. Figure 2 This is a schematic diagram illustrating a ventricular assist device 100 located in the normal position of a user's heart 120, according to an embodiment of this application. The ventricular assist device 100 can operate in the user's left heart, right heart, outside the heart, partially outside the heart, partially outside the vascular system, or in any other suitable location within the vascular system. For example, this application describes the ventricular assist device 100 placed in the left heart.

[0033] For example, the ventricular assist device 100 is used for protection during high-risk percutaneous coronary intervention (HR-PCI) procedures, maintaining hemodynamic stability in high-risk patients before the intervention to prevent severe hypotension / low cardiac output (CO) and to allow sufficient time for optimal and complete revascularization. The ventricular assist device 100 can be percutaneously inserted into the aorta 124 via the femoral artery 122 and then through the aorta 124 into the left ventricle 128. For example, the ventricular assist device 100 can be percutaneously inserted into the aorta 124 via the axillary artery 123 and then through the aorta 124 into the left ventricle. In other embodiments, the ventricular assist device 100 can also be directly inserted into the aorta 124 and through the aortic valve 126 into the left ventricle 128. During operation, the ventricular assist device 100 pumps blood from the left ventricle 128 into the aorta 124, providing auxiliary pumping function to the heart.

[0034] The ventricular assist device 100 includes a cannula 10. The cannula 10 has a proximal end and a distal end, the distal end of the cannula 10 having a fluid inlet 101 and the proximal end of the cannula 10 having a fluid outlet 102, through which blood flows in from the fluid inlet 101 and out from the fluid outlet 102 via the cannula 10.

[0035] The ventricular assist device 100 includes an impeller (not shown). The impeller is located at least partially at the proximal end of the cannula 10, such as at the fluid outlet 102 of the cannula 10, such that when the ventricular assist device 100 is in operation, it drives the impeller to rotate to pump blood from the left ventricle 128 to the aorta 124.

[0036] The ventricular assist device 100 may include a motor (not shown in the figure), which may be located inside or outside the ventricular assist device 100. This embodiment of the application illustrates the example where the motor is located inside the ventricular assist device 100. For example, the motor is located in a motor housing 201, with the distal end of the motor housing 201 connected to the proximal end of the sleeve 10. The motor drives the drive shaft to rotate, thereby driving the impeller to rotate, thus realizing the pumping function of the ventricular assist device 100.

[0037] The ventricular assist device 100 includes a catheter 30, the distal end of which is connected to the proximal end of a motor housing 201, through which a drive cable extends. As an example, the catheter 30 may accommodate electrical leads connecting the ventricular assist device 100 to an external controller. As an example, the ventricular assist device 100 also includes a distal component 110, such as a pigtail cannula, extending distally from the distal end of a cannula 10.

[0038] The ventricular assist device 100 also includes a control unit, which can be used to perform any of the embodiments, aspects, and methods of this application. The control unit may be located inside or outside the ventricular assist device 100. The control unit is used to detect relevant parameters of the ventricular assist device 100 and the user, and to control the operation of the ventricular assist device 100. For example, the control unit supplies current to the motor through one or more wires and detects the current through a current detection circuit (such as a phase current detection circuit); estimates the current pumping flow rate based on the received current; controls the rotational speed of the ventricular assist device 100 according to received instructions; and further detects whether there are abnormal events such as suction or reflux based on the pumping flow rate and rotational speed, etc.

[0039] The ventricular assist device 100 is positioned such that the cannula 10 extends across the user's aortic valve 126, with the distal end of the cannula 10 located in the user's left ventricle 128 and the proximal end of the cannula 10 located in the user's aorta 124.

[0040] For example, the ventricular assist device 100 may also include a plurality of pressure sensors that can be positioned on the outer surface of the fluid inlet 101 and / or the outer surface of the fluid outlet of the ventricular assist device 100 for real-time measurement of the patient’s left ventricular pressure and / or aortic pressure.

[0041] During the operation of the ventricular assist device 100, due to blood flow, the pumping flow rate of the ventricular assist device 100 needs to be synchronized with the patient's cardiac cycle to avoid problems such as aspiration and collapse. For example, when the blood flow into the heart decreases, blood may be pumped out of the ventricle by the ventricular assist device 100 at a rate faster than the ventricular filling rate. This usually affects the pressure difference between the inside and outside of the left ventricle 128. A prolonged pressure difference can cause the left ventricular pressure to fall below the aortic pressure, and in severe cases, it can even lead to ventricular aspiration. Furthermore, the rapid pumping of blood out of the left ventricle 128 can prevent the ventricular pressure from reaching a level sufficient to open the aortic valve leaflets, causing the heart to stop beating during systole. This can cause aortic valve regurgitation 126, meaning that the valve cannot close completely during diastole, causing blood to flow back from the aorta 124 into the left ventricle 128. This can lead to thrombus formation in the right atrium, causing pulmonary hypertension, pulmonary embolism, and in severe cases, exacerbating heart failure.

[0042] Based on this, this application proposes an abnormality detection method for a ventricular assist device (VAD), which obtains the pumping flow rate of the VAD 100 and determines whether there is an abnormality in the VAD 100 by the changing trend and magnitude of the pumping flow rate, thereby improving the accuracy of abnormality detection.

[0043] Based on the above description, this application will now be described from the perspective of method examples.

[0044] Please see Figure 3 , Figure 3 This is a schematic flowchart of an abnormality detection method for a ventricular assist device provided in an embodiment of this application, which is applied to, for example... Figure 1 The ventricular assist device shown. (Example) Figure 3 As shown, the method includes the following steps.

[0045] S310. Obtain a first pumping flow rate and a second pumping flow rate, wherein the first pumping flow rate is the maximum pumping flow rate of the ventricular assist device during a first cycle when the device is running at the target speed, and the second pumping flow rate is the minimum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed, and the first cycle is the time interval between adjacent first pumping flow rates or second pumping flow rates.

[0046] During operation of the ventricular assist device 100 within the user's body, the pumping flow rate of the ventricular assist device 100 depends on the work it needs to do to overcome resistance and pump blood from the left ventricle 128 to the aorta 124. The amount of work done by the ventricular assist device 100 can be quantified as the amount of current required to power the motor; that is, the motor current corresponds to the amount of current delivered to the motor of the ventricular assist device 100 when it is operating within the user. The motor load varies during different phases of the user's cardiac cycle. When the pressure differential in the user's heart changes, the motor current also changes to maintain a constant rotor speed. For example, when the rate of blood flow into the aorta 124 increases (such as during cardiac contraction), the current required by the motor will increase. Therefore, changes in the motor current can help characterize cardiac performance. In other words, during operation, the ventricular assist device 100 exhibits a current-flow characteristic curve, where a larger current corresponds to more work done by the ventricular assist device 100, i.e., a larger pumping flow rate.

[0047] The current of the ventricular assist device 100 can be measured by a phase current detection circuit or any other suitable means (such as a current sensor). This current-flow characteristic curve can be pre-stored in the control unit. Before the ventricular assist device 100 leaves the factory, it can be placed in a testing system to test the relationship between the pumping flow rate and current at different speeds, and then the current-flow characteristic curve can be stored in the control unit. The control unit can store the detected current in real time.

[0048] When the ventricular assist device 100 is running at a first rotational speed, after the control unit acquires the current curve within the first cycle, it estimates the corresponding flow curve using a pre-stored current-flow characteristic curve. These multiple pumping flow rates can be pumping flow rates collected from the flow curves at a sampling frequency. The first cycle can be the patient's cardiac cycle. The control unit can determine the time interval between the troughs or peaks of adjacent pumping flow rates in the flow curve as the patient's cardiac cycle, and then judge whether there is an abnormality based on the trend of the ventricular assist device 100's pumping flow rate change within a cardiac cycle, i.e., whether its pumping flow rate matches the user's needs.

[0049] Specifically, after the ventricular assist device 100 is operational, the control unit collects multiple pumping flow rates according to a sampling frequency. The time interval between the trough or peak values ​​of two adjacent pumping flow rates is taken as the first cycle. Then, the first pumping flow rate and the second pumping flow rate in each first cycle are acquired respectively. The ventricular assist device 100 is monitored for abnormalities in real time based on the first and second pumping flow rates.

[0050] S320. Calculate the target value, wherein the target value is the ratio of the target flow difference to the first average flow, the target flow difference is the difference between the first pumping flow and the second pumping flow, and the first average flow is the average pumping flow of the ventricular assist device during the first cycle.

[0051] In this application, the control unit can calculate the fluctuation of the pumping flow rate within each first cycle, and then determine whether the fluctuation matches the expected fluctuation of the pumping flow rate. The control unit calculates the difference between the first pumping flow rate and the second pumping flow rate, as well as the average pumping flow rate within the first cycle. By calculating the ratio of the target flow rate difference to the first average flow rate, the fluctuation index of the pumping flow rate of the ventricular assist device 100 can be determined. This allows for the determination of whether the current ventricular assist device 100 is abnormal.

[0052] S330. Determine whether the ventricular assist device is abnormal based on the first pumping flow rate, the second pumping flow rate, and the target value.

[0053] When the ventricular assist device 100 operates at a constant speed, the ideal pumping flow rate of the ventricular assist device 100 is as follows: Figure 4 As shown, it is synchronized with the patient's cardiac cycle. At the beginning of the cardiac cycle, the pumping flow of the ventricular assist device 100 is relatively low due to the relatively large difference between the aortic pressure and the left ventricular pressure. During the initial portion of ventricular systole, the increase in left ventricular pressure reduces the difference between the aortic pressure and the left ventricular pressure, resulting in a corresponding increase in pumping flow due to the decrease in the pressure gradient across the ventricular assist device 100. During the ejection of blood from the left ventricle 108 into the aorta 124, the pumping flow gradually decreases as the aortic pressure gradually increases relative to the left ventricular pressure. After the natural aortic valve 126 is closed, the pumping flow decreases significantly in response to the increase in the pressure gradient across the ventricular assist device 100 due to the decrease in left ventricular pressure. After the mitral valve opens, the pumping flow gradually increases in response to the gradual decrease in the pressure gradient across the ventricular assist device 100, primarily due to the gradual decrease in aortic pressure.

[0054] Based on this, when the ventricular assist device 100 operates at a constant speed, the amplitude and trend of its pumping flow rate are within a certain range. Therefore, when the ventricular assist device 100 is malfunctioning, the pumping flow rate of the ventricular assist device 100 will also be abnormal. The control unit can determine whether the ventricular assist device 100 is malfunctioning based on the magnitude of the first pumping flow rate, the second pumping flow rate, and the target value.

[0055] Optionally, determining whether the ventricular assist device is abnormal based on the first pumping flow rate, the second pumping flow rate, and the target value includes: if the first pumping flow rate is greater than or equal to a first preset flow rate and the second pumping flow rate is greater than or equal to a second preset flow rate, determining that the ventricular assist device is malfunctioning and causing aortic valve regurgitation; if the target value is less than the first value, determining that the aortic valve has moderate regurgitation; if the target value is less than the second value, determining that the aortic valve has high regurgitation, where the second value is less than the first value.

[0056] The ventricular assist device 100 is inserted into the aorta 124 and passes through the aortic valve 126 into the left ventricle 128, with its fluid inlet 101 in the left ventricle 128 and its fluid outlet 102 in the aorta 124, thereby pumping blood from the left ventricle 128 to the aorta 1241. However, the use of the ventricular assist device 100 may result in aortic valve 126 insufficiency, meaning that the aortic valve 126 cannot properly seal and isolate the left ventricle 128 and the aorta 124 during diastole. For fully implanted or long-term used ventricular assist devices 100, aortic valve 126 insufficiency may be due to malfunction of the ventricular assist device 100, causing the left ventricular pressure to be insufficient to open the aortic valve leaflets, resulting in the heart losing its pulse during systole.

[0057] When regurgitation occurs in aortic valve 126, the pumping flow of ventricular assist device 100 is unaffected during the opening of aortic valve 126. During the closing of aortic valve 126, such as during diastole, the aorta 124 and left ventricle 128 remain in communication due to incomplete or non-closing of aortic valve 126. The left ventricular pressure does not decrease and the pressure difference between the aorta and the left ventricle approaches zero, resulting in regurgitation during diastole. Blood flows back to the left ventricle through the incompletely closed aortic valve 126.

[0058] The control unit calculates the target value in real time for each first cycle, compares the target value, the first pump flow rate and the second pump flow rate with the preset value, and determines whether there is aortic valve 126 regurgitation based on the comparison result.

[0059] For example, the method further includes: acquiring a target characteristic curve, the target characteristic curve being a pressure-flow characteristic curve of the ventricular assist device when it operates at a target rotational speed; and determining a first preset flow rate based on the target characteristic curve, the first preset flow rate being the pumping flow rate of the ventricular assist device at a preset pressure difference.

[0060] To determine whether the ventricular assist device 100's pumping flow rate is abnormal, the control unit can acquire a first preset flow rate for comparison with the first pumping flow rate. For example... Figure 4 As shown, the ventricular assist device 100 reaches its maximum pumping flow rate when the aortic valve 126 is closed during the systolic phase of the cardiac cycle (i.e., the aortic pressure equals the left ventricular pressure). In other words, the ventricular assist device 100 reaches its maximum pumping flow rate near the point where the pressure difference across its terminals is zero. Based on this, the control unit can use the pumping flow rate corresponding to a zero pressure difference across the ventricular assist device 100 as the first preset flow rate. When the maximum pumping flow rate of the ventricular assist device 100 is greater than the pumping flow rate corresponding to a zero pressure difference, it indicates that aortic valve 126 regurgitation may have increased the blood volume within the left ventricle 128, potentially increasing the pumping flow rate of the ventricular assist device 100 during systole.

[0061] In this application, before the ventricular assist device 100 leaves the factory, it can be placed in a test environment to measure the characteristic curves of its pumping flow rate and ventricular pressure difference at different rotational speeds. Then, the pressure-flow characteristic curves for each rotational speed are stored in the control unit. When the ventricular assist device 100 is running, the target characteristic curve at the current rotational speed is obtained, and the pumping flow rate corresponding to a pressure difference of 0 in the target characteristic curve is determined as the first preset flow rate. Since aortic valve insufficiency results in a constant presence of blood in the left ventricle, increasing the minimum pumping flow rate in the ventricular assist device, the second preset flow rate can be set to values ​​close to 0, such as 0, 0.1 L / min, 0.2 L / min, or 0.3 L / min.

[0062] Specifically, the control unit compares the first pumping flow rate with a first preset flow rate and the second pumping flow rate with a second preset flow rate. If the first pumping flow rate is greater than or equal to the first preset flow rate and the second pumping flow rate is greater than or equal to the second preset flow rate, it is determined that aortic valve 126 regurgitation is caused by abnormal operation of the ventricular assist device 100. When aortic valve 126 regurgitates, the fluctuation index of the pumping flow rate of the ventricular assist device 100 will be less than the fluctuation index of the pumping flow rate of the ventricular assist device 100 under normal conditions. Therefore, when aortic valve 126 regurgitation is determined, the degree of aortic valve 126 regurgitation can be determined based on the fluctuation index of the pumping flow rate. Specifically: if the target value is less than the first value, it indicates that the current aortic valve 126 has moderate regurgitation; if the target value is less than the second value, it indicates that the current aortic valve 126 has high regurgitation.

[0063] Furthermore, the control unit can alarm and display the aortic valve 126 regurgitation and provide corresponding suggestions according to the degree of regurgitation. For example, if the aortic valve 126 regurgitation is moderate, it can be suggested to increase the rotation speed of the ventricular assist device 100 to increase the left ventricular pressure; if the aortic valve 126 regurgitation is severe, it can be suggested to remove the pump to solve the aortic valve 126 regurgitation problem first.

[0064] The first and second values ​​can be set according to clinical trials. For example, the first value is set to 0.5 and the second value is set to 0.2.

[0065] For example, the method further includes: determining a target pressure difference corresponding to the first average flow rate based on the target characteristic curve; if the target pressure difference is continuously equal to the preset pressure difference and the target value is continuously greater than or equal to the second preset flow rate during the second period, then it is determined that the position of the ventricular assist device is abnormal and the second period is greater than the first period.

[0066] The relative position of the ventricular assist device 100 within the heart during operation determines whether the interventional ventricular assist device can assist the patient in achieving the pumping function. The ventricular assist device 100 is implanted into the patient's heart via a guidewire and positioned as desired, with the proximal end of the cannula 10 located in the patient's aorta 124 and the distal end in the patient's left ventricle 128. After the procedure, the patient requires ventricular assist device 100 support for a period of time. During this time, the position of the ventricular assist device 100 within the patient cannot be monitored in a timely and real-time manner, and patient movement may cause displacement of the ventricular assist device 100, affecting the patient's life safety. Therefore, this application allows for real-time monitoring of the position of the ventricular assist device 100 within the patient's body during operation, enabling early detection of abnormal ventricular assist device position and providing alarm prompts, thereby improving intervention, reducing risk events, and enhancing patient safety.

[0067] When the ventricular assist device 100 is abnormally positioned, i.e., both the fluid inlet 101 and the fluid outlet 102 are located within the aorta 124 or the left ventricle 128, the pressure difference between the fluid outlet 102 and the fluid inlet 101 is close to zero. Since the ventricular assist device 100 cannot pump blood, its average pumping flow rate is also close to the pumping flow rate corresponding to a pressure difference of zero on the pressure-flow characteristic curve at the current operating speed. Simultaneously, due to the synchronous pressure changes at the fluid outlet 102 and the fluid inlet 101, the pressure difference remains unchanged, resulting in flow rate fluctuations close to zero. When the above conditions of pressure difference and flow rate are simultaneously met, it can be determined that the current ventricular assist device 100 is abnormally positioned.

[0068] Specifically, the second cycle is the duration of multiple cardiac cycles. Within each cardiac cycle, the average pumping flow rate is calculated. Then, based on the target characteristic curve, the target differential pressure corresponding to the average pumping flow rate is determined, and the target value within each cardiac cycle is calculated. If, within these multiple cardiac cycles, the target differential pressure remains equal to or close to 0, and the target value remains >= 0 or close to 0, the current position of the ventricular assist device 100 within the patient's body is determined to be abnormal, and an alarm is triggered when the position is abnormal to ensure the patient's life safety.

[0069] In one possible example, the method further includes: obtaining the second pumping flow rate within n of the first cycle, where n is a positive integer; if all n of the second pumping flow rates are less than the second preset flow rate, then determining that there is reflux in the ventricular assist device and triggering an alarm.

[0070] When the rotation speed of the ventricular assist device 100 is too low and the aortic pressure is higher than the left ventricular pressure, the blood pumped to the aorta 124 may flow back to the left ventricle 128 through the ventricular assist device 100. That is, the blood flows back from the fluid outlet 102 to the fluid inlet 101 through the ventricular assist device 100, thereby causing the blood pumped to the aorta 1241 to flow back to the left ventricle 128, resulting in insufficient blood supply and increasing the load on the left ventricle 128.

[0071] During the operation of the ventricular assist device 100, the control unit can also monitor in real time whether there is reflux in the ventricular assist device 100. Specifically, the control unit obtains the minimum pumping flow rate (i.e., the second pumping flow rate) for each of the n cardiac cycles, where n can be 10, 20, 30, etc. If the second pumping flow rate in all n cardiac cycles is less than 0, it can be determined that there is reflux in the ventricular assist device 100. An alarm is then triggered when reflux is present, and the current rotational speed and pumping flow rate are displayed and stored as reflux alarm thresholds.

[0072] In this embodiment, the control unit monitors in real time whether there is a reflux problem in the ventricular assist device 100, and then issues an alarm when there is a reflux problem, which can detect and reduce the reflux in the ventricular assist device 100 as early as possible and improve the pumping efficiency of the ventricular assist device 100.

[0073] In one possible example, the method further includes: obtaining a first flow threshold and a second flow threshold; adjusting the target rotational speed to adjust the first flow threshold and the second flow threshold; and determining that the ventricular assist device is retractable if both the first flow threshold and the second flow threshold are equal to the second pumping flow rate.

[0074] The interventional ventricular assist device 100, as a circulatory support method during and after PCI, can reduce surgical risks and improve prognosis. After implantation of the interventional ventricular assist device 100, cardiac function can be improved or even restored, thus allowing for pump weaning. In this application, when pump weaning is required, the control unit can perform a pump weaning assessment of the ventricular assist device 100 to accurately assess whether the patient can be weaned off the ventricular assist device 100.

[0075] Whether a patient can be weaned off the ventricular assist device 100 depends primarily on whether the patient's cardiac pumping capacity can support their needs. Therefore, it is necessary to accurately simulate the patient's own pumping capacity after the ventricular assist device 100 is withdrawn. In other words, the patient's own pumping capacity can meet the user's needs when the pumping flow rate of the ventricular assist device 100 approaches zero; that is, the pumping flow rate requirement of the ventricular assist device 100 gradually approaches zero. Therefore, upon receiving a withdrawal command, the control unit can acquire a first flow rate threshold and a second flow rate threshold. Based on the first and second flow rate thresholds, the rotational speed of the ventricular assist device 100 is continuously decreased or increased to stabilize the pumping flow rate of the ventricular assist device 100 and bring the average pumping flow rate close to zero.

[0076] The adjustment of the target rotational speed to adjust the first flow threshold and the second flow threshold includes: collecting the i-th pumping flow and the (i+1)-th pumping flow when the ventricular assist device is running at the target rotational speed, where i is a positive integer; if the i-th pumping flow is greater than the (i+1)-th pumping flow and the (i+1)-th pumping flow is greater than the first flow threshold, then the target rotational speed is reduced by a first acceleration, and the first flow threshold is reduced; if the i-th pumping flow is less than the (i+1)-th pumping flow and the (i+1)-th pumping flow is less than the second flow threshold, then the target rotational speed is increased by a second acceleration, and the second flow threshold is increased; let i = i+1, and repeat the above steps until a first duration is reached, or the target rotational speed exceeds a preset rotational speed range.

[0077] Specifically, the control unit collects multiple pumping flow rates from the flow curve according to the sampling frequency, and then compares two adjacent pumping flow rates. If the i-th pumping flow rate is greater than the (i+1)-th pumping flow rate and both are greater than the first flow threshold, the current rotation speed can be reduced to lower the peak value of the ventricular assist device 100's pumping flow rate and lower the first flow threshold. If the i-th pumping flow rate is less than the (i+1)-th pumping flow rate and both are less than the first flow threshold, the current rotation speed can be increased to increase the trough value of the ventricular assist device 100's pumping flow rate and increase the second flow threshold. This cycle continues until a first duration is reached or the rotation speed of the ventricular assist device 100 exceeds the allowable preset rotation speed range. After the cycle ends, if the average value of the first flow threshold and the second flow threshold is equal to or close to 0, it indicates that the average pumping flow rate of the ventricular assist device 100 is close to 0 and the reflux effect within the ventricular assist device 100 is also small. At this time, the patient's own pumping capacity can meet their needs, and the conditions for pump discontinuation can be met. If, after the loop ends, the average of the first flow threshold and the second flow threshold is greater than 1, it means that the current situation is not sufficient to meet the pump withdrawal conditions, and the pump withdrawal operation cannot be performed.

[0078] The first flow threshold can be lowered by a fixed value or a variable value each time. For example, the fixed value could be set to 0.1 L / min, 0.3 L / min, 0.5 L / min, etc. For example, the control unit can calculate the average pumping flow rate within the cardiac cycle corresponding to the i-th pumping flow rate, and then lower the first flow threshold by 1 / 2, 1 / 3, 1 / 4, 1 / 5, etc., of this average pumping flow rate each time. For example, the control unit can also pre-store a mapping relationship between the current rotational speed and the reduced first flow threshold based on clinical trial data; the higher the target rotational speed, the larger the reduction in the first flow threshold.

[0079] Similarly, the first flow threshold can be increased by a fixed value or a variable value each time. For example, the fixed value can be set to 0.1 L / min, 0.3 L / min, 0.5 L / min, etc. For example, the control unit can calculate the average pumping flow rate within the cardiac cycle to which the i-th pumping flow rate belongs, and then each time the flow threshold is increased, it decreases the average pumping flow rate by 1 / 2, 1 / 3, 1 / 4, 1 / 5, etc. For example, the control unit can also pre-store the mapping relationship between the current rotational speed and the increased first flow threshold based on clinical trial data; the higher the target rotational speed, the larger the increased second flow threshold.

[0080] For example, the first acceleration is less than 0, the second acceleration is greater than 0, and the first duration can be 12h, 24h, 36h, 72h, etc. The preset speed range can be set to 23000RPM~46000RPM. For example, the control unit can use the slope of the i-th pump flow rate and the (i+1)-th pump flow rate as the first acceleration or the second acceleration.

[0081] In this embodiment, the control unit continuously increases and decreases the rotational speed of the ventricular assist device 100 to bring the average pumping flow of the ventricular assist device 100 close to zero. This allows for a more accurate simulation of the patient's condition after weaning from the ventricular assist device 100, and a more accurate assessment of whether the patient can be weaned off the ventricular assist device 100. This accurate assessment of pump withdrawal reduces the safety of pump withdrawal and the incidence of adverse events after withdrawal.

[0082] It should be noted that when i=1, the first and second flow thresholds can be user-preset default first and second flow thresholds. For example, the default first and second flow thresholds can be set to 4.0L / min and -1.0L / min, respectively.

[0083] As can be seen, this application proposes an anomaly detection method for a ventricular assist device (VAD). The method involves acquiring a first pumping flow rate and a second pumping flow rate. The first pumping flow rate is the maximum pumping flow rate of the VAD during a first cycle when the VAD operates at a target speed. The second pumping flow rate is the minimum pumping flow rate of the VAD during the first cycle when the VAD operates at the target speed. The first cycle is the time interval between adjacent first or second pumping flow rates. A target value is calculated, which is the ratio of the target flow rate difference to a first average flow rate. The target flow rate difference is the difference between the first and second pumping flow rates. The first average flow rate is the average pumping flow rate of the VAD during the first cycle. The method determines whether the VAD is abnormal based on the first pumping flow rate, the second pumping flow rate, and the target value. This application monitors the operation of the VAD in real time by adjusting the pumping flow rate and fluctuations during the cardiac cycle, improving the accuracy of anomaly detection and thus increasing the pumping efficiency of the VAD.

[0084] The above primarily describes the solutions of the embodiments of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the network device includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0085] For example, this application provides a control unit for a ventricular assist device, the control unit including one or more processors, the one or more processors being configured to: acquire a first pumping flow rate and a second pumping flow rate, the first pumping flow rate being the maximum pumping flow rate of the ventricular assist device during a first cycle when the device operates at a target rotational speed, the second pumping flow rate being the minimum pumping flow rate of the ventricular assist device during the first cycle when the device operates at the target rotational speed, the first cycle being the time interval between adjacent first pumping flow rates or second pumping flow rates; calculate a target value, the target value being the ratio of a target flow rate difference to a first average flow rate, the target flow rate difference being the difference between the first pumping flow rate and the second pumping flow rate, the first average flow rate being the average pumping flow rate of the ventricular assist device during the first cycle; and determine whether the ventricular assist device is malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value.

[0086] For example, this application also provides a ventricular assist device, characterized in that the ventricular assist device includes:

[0087] case;

[0088] An impeller disposed within the housing;

[0089] A control unit for controlling the rotation of the impeller, the control unit being used in some or all of the steps described in the method described above.

[0090] For example, this application also provides a medical device that includes the control device or ventricular assist device described above.

[0091] The control devices of the above-mentioned schemes have the function of implementing the corresponding steps performed by the medical device in the above-mentioned methods; the function can be implemented by hardware or by hardware executing corresponding software.

[0092] In embodiments of this application, the control device may also be a chip or a chip system, such as a system on chip (SoC).

[0093] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of a medical device provided in an embodiment of this application. The medical device includes: one or more processors, one or more memories, one or more communication interfaces, and one or more programs; the one or more programs are stored in the memories and configured to be executed by the one or more processors.

[0094] The above procedure includes instructions for performing the following steps:

[0095] A first pumping flow rate and a second pumping flow rate are obtained. The first pumping flow rate is the maximum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The second pumping flow rate is the minimum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The first cycle is the time interval between adjacent first pumping flow rates or second pumping flow rates.

[0096] Calculate a target value, the target value being the ratio of a target flow difference to a first average flow, the target flow difference being the difference between the first pumping flow and the second pumping flow, and the first average flow being the average pumping flow of the ventricular assist device during the first cycle;

[0097] The ventricular assist device is determined to be malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value.

[0098] All relevant content in each scenario involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0099] It should be understood that the aforementioned memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store information about the device type.

[0100] In the embodiments of this application, the processor of the above-described device may be a Central Processing Unit (CPU), which may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0101] It should be understood that "at least one" in the embodiments of this application refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0102] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, "first information" and "second information" are only used to distinguish different information and do not indicate differences in the content, priority, sending order, or importance of these two types of information.

[0103] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly manifested as execution by a hardware processor, or as a combination of hardware and software units within the processor. The software units can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor executes the instructions in the memory, combining them with its hardware to complete the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0104] This application also provides a computer storage medium storing a computer program for electronic data interchange, which causes a computer to perform some or all of the steps of any of the methods described in the above method embodiments.

[0105] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments. This computer program product can be a software installation package.

[0106] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0107] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0108] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0109] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this application, depending on actual needs.

[0110] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0111] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or TRP, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0112] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage device, which may include a flash drive, ROM, RAM, disk, or optical disk, etc.

[0113] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A control unit for a ventricular assist device, characterized in that, The control unit includes one or more processors, which are configured to perform the following steps: A first pumping flow rate and a second pumping flow rate are obtained. The first pumping flow rate is the maximum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The second pumping flow rate is the minimum pumping flow rate of the ventricular assist device during the first cycle when the device is running at the target speed. The first cycle is the time interval between adjacent first pumping flow rates or second pumping flow rates. Calculate a target value, the target value being the ratio of the target flow difference to the first average flow, the target flow difference being the difference between the first pumping flow and the second pumping flow, and the first average flow being the average pumping flow of the ventricular assist device during the first cycle; The ventricular assist device is determined to be malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value. The step of determining whether the ventricular assist device is malfunctioning based on the first pumping flow rate, the second pumping flow rate, and the target value includes: If the first pumping flow rate is greater than or equal to the first preset flow rate and the second pumping flow rate is greater than or equal to the second preset flow rate, it is determined that the ventricular assist device is malfunctioning and causing aortic valve regurgitation. The first preset flow rate is the pumping flow rate corresponding to a pressure difference of 0 in the target characteristic curve, and the second preset flow rate is close to 0. The target characteristic curve is the pressure-flow characteristic curve of the ventricular assist device when it is running at the target speed. If the target value is less than 0.5, the aortic valve is determined to have moderate regurgitation. If the target value is less than 0.2, the aortic valve is determined to be highly regurgitated.

2. The control unit according to claim 1, characterized in that, The control unit is also configured to perform the following steps: Obtain the target feature curve; The first preset flow rate is determined based on the target characteristic curve.

3. The control unit according to claim 2, characterized in that, The control unit is also configured to perform the following steps: Based on the target characteristic curve, determine the target pressure difference corresponding to the first average flow rate; If, during the second cycle, the target pressure difference remains equal to the preset pressure difference and the target value remains greater than or close to 0, then the position of the ventricular assist device is determined to be abnormal, and the second cycle is longer than the first cycle.

4. The control unit according to claim 1, characterized in that, The control unit is also configured to perform the following steps: Obtain the first and second traffic thresholds; Adjust the target rotational speed to adjust the first flow rate threshold and the second flow rate threshold; If both the first flow threshold and the second flow threshold are equal to the second pumping flow rate, then the ventricular assist device is determined to be removable.

5. The control unit according to claim 4, characterized in that, In adjusting the target rotational speed to adjust the first flow rate threshold and the second flow rate threshold, the control unit is specifically configured to perform the following steps: The ventricular assist device is used to collect the i-th pumping flow rate and the (i+1)-th pumping flow rate when it is running at the target rotational speed, where i is a positive integer; If the i-th pumping flow rate is greater than the (i+1)-th pumping flow rate and the (i+1)-th pumping flow rate is greater than the first flow rate threshold, then the target rotational speed is reduced by a first acceleration and the first flow rate threshold is reduced. If the i-th pumping flow rate is less than the (i+1)-th pumping flow rate and the (i+1)-th pumping flow rate is less than the second flow rate threshold, then the target rotational speed is increased by the second acceleration, and the second flow rate threshold is increased. Let i = i + 1, and repeat the above steps until the first duration is reached or the target speed exceeds the preset speed range.

6. The control unit according to claim 1, characterized in that, The control unit is also configured to perform the following steps: Obtain n second pumping flow rates within the first cycle, where n is a positive integer; If the flow rates of all n second pumps are less than the second preset flow rate, then it is determined that there is reflux in the ventricular assist device and an alarm is triggered.

7. A ventricular assist device, characterized in that, The ventricular assist device includes: case; An impeller disposed within the housing; A control unit for controlling the rotation of the impeller, the control unit being configured to perform the steps as described in any one of claims 1-6.

8. A medical device, characterized in that, The device includes a processor, a memory, and a communication interface, wherein the memory stores one or more programs, and the one or more programs are executed by the processor, the one or more programs including instructions for performing the steps of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for electronic data interchange, wherein the computer program causes a computer to perform the steps as described in any one of claims 1-6.

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