Transcutaneous circulatory support systems and devices including detection of aortic valve regurgitation

Abstract

The percutaneous circulation support system includes an impeller and a motor operably coupled to the impeller. A controller is operably coupled to the motor and is configured to drive the motor, thereby causing the motor to rotate the impeller and generate blood flow, to determine that the system's operating parameters deviate from a symmetrical waveform, and in response to determining that the operating parameters deviate from a symmetrical waveform, to provide a warning of aortic valve insufficiency.

Description

Technical Field

[0001] The present disclosure relates to percutaneous circulatory assist systems and devices. More particularly, the present disclosure relates to percutaneous circulatory assist systems and devices capable of detecting aortic valve insufficiency, also known as aortic regurgitation.

Background Art

[0002] Percutaneous circulatory assist devices or blood pumps can provide temporary assistance for up to several weeks in patients with reduced cardiac function or cardiac output. Some of these devices, specifically left ventricular assist devices, facilitate the flow of blood from the left ventricle, across the aortic valve, into the aorta. However, the use of a left ventricular assist device can cause aortic valve insufficiency, where the aortic valve cannot properly seal and isolate the left ventricle and the aorta during diastole. In the case of a fully implanted / long-term left ventricular assist device, aortic valve insufficiency can develop because the ventricular pressure does not reach a level sufficient to open the valve cusps of the aortic valve, causing the heart to lose pulsatility during systole. The valve cusps can fuse together, and the valve can deteriorate, leading to a loss of sealing function. In these situations, the left ventricular assist device indirectly affects valve function by changing ventricular contractility. Aortic valve insufficiency can also occur acutely during the use of a short-term left ventricular assist device placed across the aortic valve. In these situations, the device can prevent the valve cusps from closing completely if the force of the device on the valve cusps is greater than the contractile force of the valve cusps.

Summary of the Invention

Means for Solving the Problems

[0003] In Example 1, the percutaneous circulatory support system includes an impeller and a motor operably coupled to the impeller. A controller is operably coupled to the motor and is configured to drive the motor, thereby causing the motor to rotate the impeller and generate blood flow, to determine that the operating parameters of the system deviate from a symmetrical waveform, and in response to determining that the operating parameters deviate from a symmetrical waveform, to provide a warning of aortic valve insufficiency.

[0004] In Example 2, the controller in the transcutaneous circulation support system of Example 1 is configured to determine when the operating parameters deviate from a square waveform.

[0005] In Example 3, in one of the transcutaneous circulatory support systems in Examples 1-2, the controller is configured to determine that the operating parameters deviate from a symmetrical waveform within the patient's cardiac cycle.

[0006] In Example 4, in one of the percutaneous circulatory support systems in Examples 1-2, the controller is configured to determine when the operating parameters deviate from a symmetric waveform during the patient's cardiac cycle by comparing an increase in the operating parameters during systole with a decrease in the operating parameters after a dicrotic notch.

[0007] In Example 5, comparing an increase in operating parameters with a decrease in operating parameters in the transcutaneous circulation support system of Example 4 includes: high-pass filtering of the operating parameters to provide a parameter rate; low-pass filtering of the first portion of the parameter rate to provide an upper envelope corresponding to an increase in operating parameters; converting the second portion of the parameter rate into a positive parameter rate; low-pass filtering of the positive parameter rate to provide a lower envelope corresponding to a decrease in operating parameters; determining the ratio of the upper envelope to the lower envelope; and comparing the ratio with a threshold.

[0008] In Example 6, the threshold for the transcutaneous circulation support system in Example 5 is 0.5. In Example 7, in any of the transcutaneous circulatory support systems of Examples 5-6, the controller is further configured to apply saturation action to the parameter rate.

[0009] In Example 8, in any of the transcutaneous circulatory support systems of Examples 1-7, the controller is further configured to receive feedback from the motor and adjust the operating parameters based on the feedback.

[0010] In Example 9, in any of the transcutaneous circulation support systems from Examples 1 to 8, the operating parameter is the commanded voltage provided by the controller to drive the motor.

[0011] In Example 10, in any of the transcutaneous circulation support systems from Examples 1 to 9, the operating parameter is the current supplied to the motor. In Example 11, the percutaneous circulation assistance system includes an impeller and a motor operably coupled to the impeller. A controller is operably coupled to the motor and is configured to provide a command voltage to the motor so that the motor rotates the impeller to generate blood flow, to high-pass filter the command voltage to provide a command voltage rate, to low-pass filter a first portion of the command voltage rate to provide an upper voltage envelope corresponding to an increase in the command voltage, to convert a second portion of the command voltage rate into a positive voltage rate, to low-pass filter the positive voltage rate to provide a lower voltage envelope corresponding to a decrease in the command voltage, to determine the ratio of the upper voltage envelope to the lower voltage envelope, to compare the ratio to a threshold, and to provide a warning of aortic valve insufficiency in response to the determination that the ratio is less than the threshold.

[0012] In Example 12, the controller is further configured to receive feedback from the motor and adjust the command voltage based on the feedback, in the transcutaneous circulation support system of Example 11.

[0013] In Example 13, in the transcutaneous circulation support system of Example 12, the controller is configured to adjust the command voltage based on feedback, and then to provide a command voltage rate by high-pass filtering the command voltage.

[0014] In Example 14, the threshold is 0.5 in any of the transcutaneous circulation support systems in Examples 11-13. In Example 15, in any of the transcutaneous circulatory support systems of Examples 11-14, the controller is further configured to apply saturation operation to the commanded voltage rate.

[0015] In Example 16, the percutaneous circulation support system includes a housing configured to be placed inside the patient's body. An impeller is held within the housing, and a motor is operably coupled to the impeller. A controller is operably coupled to the motor, and the controller is configured to drive the motor, thereby causing the motor to rotate the impeller relative to the housing to generate blood flow through the housing, to determine that the system's operating parameters deviate from a symmetrical waveform, and in response to the determination that the operating parameters deviate from a symmetrical waveform, to provide a warning of aortic valve regurgitation.

[0016] In Example 17, the controller in the transcutaneous circulation support system of Example 16 is configured to determine when the operating parameters deviate from a square waveform. In Example 18, in the percutaneous circulatory support system of Example 16, the controller is configured to determine that the operating parameters deviate from a symmetrical waveform within the patient's cardiac cycle.

[0017] In Example 19, the percutaneous circulatory support system of Example 18 is configured to determine when the operating parameters deviate from a symmetric waveform during the patient's cardiac cycle by comparing an increase in the operating parameters during systole with a decrease in the operating parameters after a heavy notch.

[0018] In Example 20, comparing an increase in operating parameters with a decrease in operating parameters in the transcutaneous circulation support system of Example 19 includes: high-pass filtering of the operating parameters to provide a parameter rate; low-pass filtering of a first portion of the parameter rate to provide an upper envelope corresponding to an increase in operating parameters; converting a second portion of the parameter rate into a positive parameter rate; low-pass filtering of the positive parameter rate to provide a lower envelope corresponding to a decrease in operating parameters; determining the ratio of the upper envelope to the lower envelope; and comparing the ratio with a threshold.

[0019] In Example 21, the threshold is 0.5 in the transcutaneous circulation support system of Example 20. In Example 22, the controller is further configured in the transcutaneous circulation support system of Example 16 to receive feedback from the motor and adjust the operating parameters based on the feedback.

[0020] In Example 23, in the transcutaneous circulation support system of Example 16, the operating parameter is the command voltage provided by the controller to drive the motor. In Example 24, the transcutaneous circulation support system includes a housing configured to be placed inside the patient's body, an impeller held within the housing, and a motor operably coupled to the impeller. A controller is operably coupled to the motor, and the controller is configured to supply a command voltage to the motor so that the motor rotates the impeller relative to the housing to generate blood flow through the housing, to high-pass filter the command voltage to provide a command voltage rate, to low-pass filter a first portion of the command voltage rate to provide an upper voltage envelope corresponding to an increase in the command voltage, to convert a second portion of the command voltage rate into a positive voltage rate, to low-pass filter the positive voltage rate to provide a lower voltage envelope corresponding to a decrease in the command voltage, to determine the ratio of the upper voltage envelope to the lower voltage envelope, to compare the ratio to a threshold, and to provide a warning of aortic valve insufficiency in response to the determination that the ratio is less than the threshold.

[0021] In Example 25, the controller is further configured to receive feedback from the motor and adjust the command voltage based on the feedback, in the transcutaneous circulation support system of Example 24.

[0022] In Example 26, in the transcutaneous circulation support system of Example 25, the controller is configured to adjust the command voltage based on feedback, and then to provide a command voltage rate by high-pass filtering the command voltage.

[0023] In Example 27, in the percutaneous circulatory assist system of Example 24, the threshold value is 0.5. In Example 28, a percutaneous circulatory assist system includes a housing, an impeller disposed within the housing, a motor operably coupled to the impeller, and a controller operably coupled to the motor. A method of using the system includes driving the motor via the controller, thereby causing the motor to rotate the impeller to create blood flow through the housing, determining via the controller that an operating parameter of the system deviates from a symmetric waveform, and providing a warning of aortic valve insufficiency in response to determining via the controller that the operating parameter deviates from the symmetric waveform.

[0024] In Example 29, in the method of Example 28, determining that the operating parameter deviates from the symmetric waveform includes determining that the operating parameter deviates from a square waveform. In Example 30, in the method of Example 28, determining that the operating parameter deviates from the symmetric waveform includes determining that the operating parameter deviates from the symmetric waveform within a cardiac cycle of the patient.

[0025] In Example 31, in the method of Example 30, determining that the operating parameter deviates from the symmetric waveform includes comparing an increase in the operating parameter during systole with a decrease in the operating parameter after a heavy notch.

[0026] In Example 32, in the method of Example 31, comparing, via the controller, an increase in the operating parameter with a decrease in the operating parameter includes high-pass filtering the operating parameter to provide a parameter rate, low-pass filtering a first portion of the parameter rate to provide an upper envelope corresponding to an increase in the operating parameter, converting a second portion of the parameter rate to a positive rate, low-pass filtering the positive rate to provide a lower envelope corresponding to a decrease in the operating parameter, determining a ratio of the upper envelope to the lower envelope, and comparing the ratio with a threshold value.

[0027] In Example 33, the method of Example 28 further includes receiving feedback from the motor by the controller and adjusting the operating parameters based on the feedback via the controller.

[0028] In Example 34, in the method of Example 33, adjusting the operating parameters based on the feedback precedes determining that the operating parameters deviate from the symmetric waveform. In Example 35, in the method of Example 28, the operating parameter is the command voltage, and the method further includes providing a command voltage to the motor to drive the motor via the controller.

[0029] Although multiple embodiments are disclosed, other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description that illustrates and describes exemplary embodiments of the present invention. Therefore, the drawings and the detailed description should be considered to be essentially exemplary and not limiting.

Brief Description of the Drawings

[0030] [Figure 1] It is a side cross-sectional view of an exemplary percutaneous circulatory assist device (also interchangeably referred to herein as a "blood pump") according to an embodiment of the subject matter disclosed herein. [Figure 2] It is a schematic diagram of the electronic components of the percutaneous circulatory assist device of FIG. 1 according to an embodiment of the subject matter disclosed herein. [Figure 3] It is a graph of the command voltage versus time of the percutaneous circulatory assist device for a normal cardiac pattern. [Figure 4] It is a graph of the command voltage versus time of the percutaneous circulatory assist device for an insufficient cardiac pattern. [Figure 5]This is a flowchart of a method for operating a percutaneous circulatory support device and detecting aortic valve regurgitation, according to embodiments of the subject matter disclosed herein. [Figure 6] This is a simulated pressure-time graph within a patient for a normal cardiac cycle pattern. [Figure 7] Figure 6 shows a graph of simulated voltage and voltage rate versus time, corresponding to the simulated pressure. [Figure 8] Figure 7 shows the simulated voltage and voltage rate, along with the simulated voltage ratio and aortic valve regurgitation determination graphs. [Figure 9] This is a simulated pressure-time graph within a patient for a failing cardiac cycle pattern. [Figure 10] Figure 9 shows a graph of simulated voltage and voltage rate versus time, corresponding to the simulated pressure. [Figure 11] Figure 10 shows the simulated voltage and voltage rate, along with the simulated voltage ratio and aortic valve regurgitation determination graphs. [Modes for carrying out the invention]

[0031] While the present invention may accept various modifications and alternative forms, specific embodiments are shown in the drawings as examples and described in detail herein. However, the intent is not to limit the invention to the specific embodiments described. On the contrary, the invention is intended to encompass all modifications, equivalents, and alternatives that fall within the scope of the invention as defined by the appended claims.

[0032] The use of left ventricular assist devices can lead to aortic regurgitation, a condition in which the aortic valve fails to properly seal and isolate the left ventricle and aorta during diastole. As a result, blood improperly “backflows” from the aorta into the left ventricle, also known as aortic regurgitation. This can lead to increased ventricular afterload, decreased arterial pressure, and / or increased hemolysis, potentially impairing the effectiveness of such assist devices. Furthermore, aortic regurgitation is often difficult to detect, and as a result, physicians may not recognize the need to address the condition. Therefore, some embodiments of this disclosure focus on relatively simple and effective methods for detecting aortic regurgitation while left ventricular assist devices are in use.

[0033] Figure 1 shows a partial side cross-sectional view of an exemplary percutaneous circulation assist device 100 (also interchangeably referred to herein as a “blood pump”) according to embodiments of the subject matter disclosed herein. Device 100 may form part of a percutaneous circulation assist system, together with other devices, for example, a guidewire and an introducer sheath. More specifically, the guidewire and introducer sheath can facilitate the percutaneous delivery of device 100 to a target location within the patient’s body, such as within the patient’s heart. Alternatively, device 100 may be delivered to different target locations within the patient’s body.

[0034] Continuing to refer to Figure 1, the device 100 generally includes a housing 101 which includes an impeller housing 102 and a motor housing 104. In some embodiments, the impeller housing 102 and the motor housing 104 may be constructed integrally or monolithically. In other embodiments, the impeller housing 102 and the motor housing 104 may be separate components configured to be removable or permanently coupled. In some embodiments, the blood pump 100 may lack a separate motor housing 104, and the impeller housing 102 may be directly coupled to the motor 105 described herein, or the motor housing 104 may be constructed integrally with the motor 105 described herein.

[0035] The impeller housing 102 holds within it an impeller assembly 106. The impeller assembly 106 includes an impeller shaft 108 rotatably supported by at least one bearing, such as a bearing 110. The impeller assembly 106 also includes an impeller 112 that rotates relative to the impeller housing 102 to drive blood through the device 100. More specifically, the impeller 112 causes blood to flow out from a blood inlet 114 formed on the impeller housing 102, through the impeller housing 102, and out of a blood outlet 116 formed on the impeller housing 102. In some embodiments, as illustrated, the impeller shaft 108 and the impeller 112 may be separate components, and in other embodiments, the impeller shaft 108 and the impeller 112 may be integrated. In some embodiments, as illustrated, the inlet 114 and / or outlet 116 may each include multiple openings. In other embodiments, the inlet 114 and / or outlet 116 may each include a single opening. In some embodiments, as shown, the inlet 114 may be formed at the end of the impeller housing 102, and the outlet 116 may be formed on the side of the impeller housing 102. In other embodiments, the inlet 114 and / or the outlet 116 may be formed on other parts of the impeller housing 102. In some embodiments, the impeller housing 102 may be coupled to a distally extending cannula that receives blood and delivers it to the inlet 114.

[0036] Continuing to refer to Figure 1, the motor housing 104 holds the motor 105, which is configured to be operably coupled to and rotatably driven by the impeller 112. In the illustrated embodiment, the motor 105 rotates a drive shaft 120 coupled to a drive magnet 122. The rotation of the drive magnet 122 causes the rotation of a driven magnet 124, which is connected to and rotates with the impeller assembly 106. More specifically, in an embodiment incorporating an impeller shaft 108, the impeller shaft 108 and the impeller 112 are configured to rotate together with the driven magnet 124. In other embodiments, the motor 105 may be coupled to the impeller assembly 106 via other components.

[0037] The motor housing 104 is coupled to the catheter 126 on the opposite side of the impeller housing 102. The catheter 126 may be coupled to the motor housing 104 in various ways, such as by laser welding, soldering, or equivalent. The catheter 126 extends proximal to the motor housing 104. The catheter 126 holds the motor cable 128 within the main lumen 130, and the motor cable 128 may be operably coupled to the motor 105 to a controller (shown elsewhere) and / or power supply.

[0038] Referring further to Figure 1 and Figure 2, the controller 132 can be configured to be operably coupled to and control the motor 105. In some embodiments, the controller 132 may be located inside the motor housing 104. In other embodiments, the controller 132 may be located outside the motor housing 104 (e.g., inside a separate housing of the system 133) and coupled to the motor 105 via the motor cable 128. In some embodiments, the controller 132 may include multiple components, one or more of which may be located inside the motor housing 104. According to embodiments, the controller 132 may include, or may contain, one or more field-programmable gate arrays (FPGAs), one or more programmable logic devices (PLDs), one or more composite PLDs (CPLDs), one or more custom application-specific integrated circuits (ASICs), one or more dedicated processors (e.g., microprocessors), one or more central processing devices (CPUs), software, hardware, firmware, or any combination thereof and / or other components. Therefore, the controller 132 can be an integrated circuit (such as an ASIC or other type of circuit) programmed to perform one or more functions described herein. Although the controller 132 is referred to in the singular form herein, the controller may be implemented in multiple instances, distributed across multiple computing devices, instantiated within multiple virtual machines, and / or similar.

[0039] Continuing to refer to Figure 2, the system 133 also includes a rectifier assembly 138 that operably couples the controller 132 and the motor 105. As shown, the rectifier assembly 138 may be separate from the controller 132 and the motor 105 (for example, in a separate housing of the system 133). In other embodiments, the rectifier assembly 138 may be located in the motor housing 104 and / or combined with the controller 132.

[0040] Generally, the controller 132 is configured to analyze one or more operating parameters of the device 100 to detect aortic valve insufficiency in a patient. For example, the controller 132 includes a monitor 134 that analyzes the command voltage that the controller 132 supplies to the motor 105 via the commutator 136 of the rectifier assembly 138 to drive the motor 105 at a reference speed 140. The controller 132 also includes an error adjuster 142 that adjusts the command voltage based on feedback received from the motor 105 via the high-pass filter 144 of the rectifier assembly 138. Exemplarily, the error adjuster 142 includes a proportional error adjustment 146 and an integral error adjustment 148. In other embodiments, the controller 132 is configured to analyze one or more additional or alternative operating parameters of the device 100 to detect aortic valve insufficiency in a patient. Such operating parameters include, for example, motor current, motor speed, motor torque, and sensed arterial or ventricular pressure.

[0041] In some embodiments, the monitor 134 analyzes the waveform shape of operating parameters, such as the command voltage waveform, which changes based on the pressure gradient across the aortic valve, in order to detect aortic regurgitation. More specifically, in the case of a normal cardiac cycle pattern (i.e., no aortic regurgitation) and constant-speed control, the command voltage increases rapidly during systolic contraction (when blood pressure in the left ventricle increases rapidly) and decreases rapidly after the supernumerary notch (when blood pressure in the left ventricle decreases rapidly, between the closure of the aortic valve and the opening of the mitral valve). As shown in Figure 3, these rapid voltage changes provide a command voltage with a symmetrical waveform 300, more specifically, a square waveform, across these parts of the cardiac cycle pattern. In other words, the rate at which the voltage increases is substantially the same as the rate at which the voltage decreases. By detecting a symmetrical waveform, the monitor 134 can determine that no aortic regurgitation is present. In contrast, in the case of a failure cycle pattern (i.e., aortic valve regurgitation is present and blood flow is improperly reversed from the aorta to the left ventricle), the command voltage gradually increases before and during systolic contraction, but nevertheless, the command voltage rapidly decreases following the deep notch. As a result, as shown in Figure 4, the voltage change provides a command voltage with an asymmetric waveform 400, such as a non-square waveform (e.g., a sawtooth-like waveform). By detecting such a waveform, monitor 134 can determine that aortic valve regurgitation is present.

[0042] Referring to Figure 5, an exemplary method 500 for operating the percutaneous circulation support system 133 and detecting aortic valve insufficiency is as follows: First, the controller 132 provides a command voltage to the motor 105, thereby causing the motor 105 to rotate the impeller 112 and cause blood to flow through the housing 101. As shown in block 502, the monitor 134 also receives the command voltage. In block 504, the command voltage is high-pass filtered through the high-pass filter of the controller 132 to provide a command voltage rate. Next, in block 506, a saturation operation is applied to the command voltage rate. In block 508, a first portion of the command voltage rate corresponding to the voltage increase described herein is low-pass filtered through the low-pass filter of the controller 132 to provide a first or upper voltage envelope. In parallel with blocks 506 and 508, in block 510, a second portion of the commanded voltage rate corresponding to the voltage drop described herein is converted to a positive voltage rate (for example, by multiplying by -1). In block 512, saturation operation is applied to the positive voltage rate. In block 514, the positive voltage rate is low-pass filtered through the low-pass filter of controller 132 to provide a second or lower voltage envelope. In block 516, the ratio of the upper voltage envelope to the lower voltage envelope is determined. Next, in block 518, the ratio is compared to a threshold (for example, 0.5). If the ratio is greater than the threshold, in block 520, it is determined that aortic valve regurgitation is not present. If the ratio is less than the threshold, in block 522, it is determined that aortic valve regurgitation is present. In some embodiments, the system 133 repeats the method frequently, more specifically during each cycle of the patient's cardiac cycle pattern, or the system 133 repeats the method continuously, or performs analog calculations or emulates analog calculations.

[0043] If aortic valve regurgitation is detected (for example, over multiple cycles of a cardiac cycle pattern within a specific period, or in a single cycle of a cardiac cycle pattern), system 133 may provide a warning (e.g., a visual and / or auditory warning) to a healthcare professional, who may then modify the operation of system 133. More specifically, the healthcare professional may make a decision based on information regarding what is best to do, which may include continuing to use the device, modifying the operating settings of system 133 (e.g., the speed of motor 105), repositioning device 100 within the patient, or discontinuing the use of system 133.

[0044] Figure 6 shows the simulated pressure in a patient during a normal cardiac cycle pattern, more specifically, during approximately two cycles in such a pattern. As illustrated, a relatively large pressure gradient exists between the aorta and the left ventricle before the systolic contraction (e.g., before 4.25 seconds and 5.25 seconds) for the aortic valve to close properly and isolate the aorta from the left ventricle. Figure 7 shows the simulated voltage and voltage rate during a normal cardiac cycle pattern, more specifically, during approximately 12 cycles in such a pattern. The lower voltage envelope is shown as a negative value for clarity, instead of the positive values ​​described herein. Figure 7 includes the period shown in Figure 6, among other periods. During the systolic contraction (e.g., before 4.25 seconds and 5.25 seconds), the command voltage rate includes a relatively large positive spike 700. Following the heavy notch (e.g., at approximately 4.5 seconds and 5.5 seconds), the command voltage rate includes a relatively large negative spike 702. After the initial activation period (e.g., approximately 6 seconds), the upper and lower envelope voltages are consistently determined based on positive spikes 700 and negative spikes 702, respectively. Figure 8 shows the simulated voltage ratio of the upper envelope voltage to the lower envelope voltage and the determination of aortic regurgitation during a normal cardiac cycle pattern, more specifically, during approximately 12 cycles in such a pattern. Figure 8 includes the same period as shown in Figure 7. After the initial activation period (e.g., approximately 6 seconds), the ratio is consistently determined to be greater than the threshold (e.g., 0.5), and no aortic regurgitation is detected.

[0045] Figure 9 shows a failed cardiac cycle pattern, more specifically, simulated pressure within the patient during approximately three cycles in such a pattern. As illustrated, the aortic valve does not close properly, thereby allowing blood to flow back from the aorta into the left ventricle, so the pressures in the aorta and left ventricle are approximately equal to those before systolic contraction (e.g., 4.75 seconds, 5.75 seconds, and 6.75 seconds before). Figure 10 shows a failed cardiac cycle pattern, more specifically, simulated voltage and voltage rate during approximately 12 cycles in such a pattern. The lower voltage envelope is shown as a negative value for clarity, instead of the positive values ​​described herein. Figure 10 includes the period shown in Figure 9, among other periods. During systolic contraction (e.g., approximately 4.75 seconds, 5.75 seconds, and 6.75 seconds), the command voltage rate includes relatively large positive spikes, as shown in Figure 7. Following the heavy notches (e.g., at approximately 5.2 seconds, 6.2 seconds, and 7.2 seconds), the command voltage rate includes a relatively large negative spike of 1000. Figure 11 shows the simulated voltage ratio of the upper envelope voltage to the lower envelope voltage and the failure cycle pattern, more specifically the determination of aortic regurgitation during approximately 12 cycles in such a pattern. Figure 11 includes the same period as shown in Figure 10. At approximately 9 seconds, the ratio falls below the threshold (e.g., 0.5), resulting in the detection of aortic regurgitation.

[0046] As briefly described herein, in some embodiments, the controller 132 is configured to analyze one or more additional or alternative operating parameters of the device 100 to detect aortic regurgitation in a patient. In embodiments where the speed is strictly controlled, both the motor current and torque have waveforms similar to the voltage, and the methods described herein may be applied to the current and / or torque and thereby used to detect aortic regurgitation. In yet another example, in some embodiments, the distal portion of the device 100 includes arterial blood flow and / or a pressure sensor configured to be located in the left ventricle. The pressure waveform determined via the sensor is similar to the voltage, torque, current, and motor speed waveforms described herein, and the methods described herein can be applied to the pressure waveform to detect aortic regurgitation. In yet another example, in some embodiments, the speed of the motor 105 may be loosely controlled. In these embodiments, the command voltage remains relatively constant, and the motor speed changes significantly. In such embodiments, the methods described herein may be applied to motor speed feedback to detect aortic regurgitation.

[0047] In other embodiments, system 133 may determine that the command voltage, torque, current, or motor speed deviates from a symmetric waveform, thereby detecting aortic regurgitation in a different manner. For example, in some embodiments, a neural network may be trained to recognize asymmetric waveforms and thereby detect aortic regurgitation. As another example, in some embodiments, convolution can be used to determine the presence of an asymmetric waveform and thereby detect aortic regurgitation. As yet another example, in some embodiments, linear programming can be used to directly calculate the gradient of the waveform, thereby determining the presence of an asymmetric waveform and detecting aortic regurgitation.

[0048] In some embodiments, the controller 132 is configured to analyze one or more operating parameters of the device 100 in other ways to detect aortic regurgitation in a patient. For example, the controller 132 may monitor one or more operating parameters of the device 100 (such as command voltage, torque, current, motor speed, and / or sensed arterial or ventricular pressure). If one or more operating parameters deviate from the expected range during one or more specific parts of the cardiac cycle (e.g., diastole), the controller 132 detects aortic regurgitation. As a more specific example, the controller 132 may detect aortic regurgitation if the left ventricular pressure is greater than 30 mmHg and / or the aortic pressure is less than 60 mmHg at the end of diastole. As another example, the controller 132 can determine the first derivative of one or more operating parameters of device 100 (such as commanded voltage, torque, current, motor speed, and / or sensed arterial or ventricular pressure) over time, and detect aortic regurgitation if one or more of the first derivatives exceed a maximum threshold or fall below a minimum threshold. As yet another example, the controller 132 can determine the maximum rate of increase of one or more operating parameters of device 100 (such as commanded voltage, torque, current, motor speed, and / or sensed arterial or ventricular pressure). The controller 132 may detect aortic regurgitation if one or more of the maximum rates of increase fall below a minimum threshold.

[0049] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described herein refer to specific features, the scope of the invention also includes embodiments having different combinations of features, and embodiments that do not include all of the described features. Accordingly, the scope of the invention is intended to encompass all such alternative forms, modifications, and variations that fall within the claims, along with all their equivalents.

Claims

1. A transcutaneous circulation support system: The transcutaneous circulation support system is impeller and, A motor operably coupled to the impeller, A controller operably coupled to the motor, The motor is driven, and the motor rotates the impeller to cause blood to flow. It is determined that the operating parameters of the aforementioned system deviate from a symmetrical waveform, and A controller configured to provide a warning of aortic valve regurgitation in response to the determination that the operating parameters deviate from the symmetrical waveform, A transdermal circulation support system equipped with the following features.

2. The transcutaneous circulation assistance system according to claim 1, wherein the controller is configured to determine that the operating parameters deviate from a square waveform.

3. The percutaneous circulation support system according to claim 1 or 2, wherein the controller is configured to determine that the operating parameters deviate from the symmetric waveform within the patient's cardiac cycle.

4. The percutaneous circulation support system according to claim 1 or 2, wherein the controller is configured to determine whether the operating parameter deviates from the symmetric waveform during the patient's cardiac cycle by comparing the increase in the operating parameter during systolic contraction with the decrease in the operating parameter after the heavy notch.

5. The transcutaneous circulation support system according to claim 4, wherein the increase of the operating parameter is compared with the decrease of the operating parameter, To provide the parameter rate, the operating parameters are subjected to a high-pass filter, The first portion of the parameter rate is subjected to a low-pass filter to provide an upper envelope corresponding to the increase in the operating parameter, Converting the second portion of the parameter rate to a positive parameter rate, The positive parameter rate is subjected to a low-pass filter to provide a lower envelope corresponding to the decrease in the operating parameter, Determining the ratio of the upper envelope to the lower envelope, Comparing the aforementioned ratio with a threshold, A transdermal circulation support system equipped with the following features.

6. The transcutaneous circulation support system according to claim 5, wherein the threshold is 0.

5.

7. The transcutaneous circulation support system according to claim 5 or 6, wherein the controller is further configured to apply saturation operation to the parameter rate.

8. The transcutaneous circulation assistance system according to any one of claims 1 to 7, wherein the controller is further configured to receive feedback from the motor and adjust the operating parameters based on the feedback.

9. The transcutaneous circulation assistance system according to any one of claims 1 to 8, wherein the operating parameter is a command voltage provided by the controller to drive the motor.

10. The transcutaneous circulation assistance system according to any one of claims 1 to 9, wherein the operating parameter is the current supplied to the motor.

11. A transcutaneous circulation support system, wherein the transcutaneous circulation support system is impeller and, A motor operably coupled to the impeller, A controller operably coupled to the motor, A command voltage is supplied to the motor, causing the motor to rotate the impeller and cause blood to flow. To provide the command voltage rate, the command voltage is subjected to a high-pass filter. The first portion of the command voltage rate is subjected to a low-pass filter to provide an upper voltage envelope corresponding to the increase in the command voltage. The second portion of the command voltage rate is converted to a positive voltage rate; To provide a lower voltage envelope corresponding to the decrease in the command voltage, the positive voltage rate is subjected to a low-pass filter; Determine the ratio of the upper voltage envelope to the lower voltage envelope; Compare the aforementioned ratio with the threshold; A controller configured to provide a warning of aortic valve regurgitation in response to the determination that the ratio is less than the threshold, A transdermal circulation support system equipped with the following features.

12. The transcutaneous circulation assistance system according to claim 11, wherein the controller is further configured to receive feedback from the motor and adjust the command voltage based on the feedback.

13. The transcutaneous circulation support system according to claim 12, wherein the controller is configured to adjust the command voltage based on the feedback and then high-pass filter the command voltage to provide the command voltage rate.

14. The transcutaneous circulation support system according to any one of claims 11 to 13, wherein the threshold is 0.

5.

15. The transcutaneous circulation assistance system according to any one of claims 11 to 14, wherein the controller is further configured to apply saturation operation to the command voltage rate.

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