Circulatory support system including a controller and a plurality of sensors and method of operating the same

Abstract

The circulatory support system includes an implantable blood pump having a housing, a rotor operable to pump blood from an inlet to an outlet, a stator, and at least two of a current sensor, a rotor position sensor, an accelerometer, and a pressure sensor. The controller has a signal processing module connected to the sensors and configured to receive data streams from each of the sensors. The signal processing module is also configured to filter the data streams received from the sensors, determine at least one of a pump operation parameter, a cardiac characteristic, and a pump control parameter based on at least two of the filtered data streams, and output the at least one of the pump operation parameter, the cardiac characteristic, and the pump control parameter to at least one of an operator interface module and a pump control module.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority to U.S. Provisional Application No. 62 / 926,141, filed Oct. 25, 2019, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure generally relates to mechanical circulatory support systems, and more specifically to an implantable blood pump assembly that includes a plurality of sensors and a controller that combines data streams received from the sensors.

Background Art

[0003] An assistive artificial heart known as a VAD is an implantable blood pump that is used for both short - term (i.e., days, months) and long - term (i.e., years or lifetime) applications when a patient's heart, such as those suffering from heart failure or congestive heart failure, cannot provide adequate circulation. Patients with heart failure use a VAD while waiting for a heart transplant or as a long - term end - of - life treatment. In another example, a patient uses a VAD during recovery from heart surgery. Thus, a VAD can assist (i.e., partially support) a weak heart or effectively replace the function of the native heart. A VAD can be implanted within a patient's body and can be powered from a power source provided inside or outside the patient's body.

[0004] A controller can be used to control the operation of an implanted VAD. The controller can be operably connected to the VAD by wired, wireless, and / or mechanical connections and used to control the operation of the VAD by supplying it with operating power (e.g., electrical and / or mechanical power) and control signals.

[0005] At least some VADs utilize feedback from one or more sensors to control the operation of the VAD. For example, some VADs use pressure sensors to measure pressure and monitor the patient's cardiac cycle to control the VAD. Although the sensors of at least some VADs provide valuable information, the quality and scope of the information provided by the sensors have drawbacks. For example, due to sensor failures and / or limitations in operating capabilities, the sensors may not be able to provide accurate information. For example, some sensors, such as current sensors, do not provide information that is available at all stages of the cardiac or pump cycle. Further, it is difficult to determine whether an individual sensor is providing accurate information. Additionally, certain values, such as cardiac characteristics and pump operating parameters, cannot be determined from the data provided by individual sensors alone, so individual sensors may not provide optimal clinical information for operating the VAD.

[0006] Accordingly, there is a need for an improved VAD that combines information from multiple sensors to monitor the patient's cardiac cycle and control the operation of the VAD. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0007] The present disclosure relates to a circulatory support system including an implantable blood pump and a controller. The implantable blood pump has a housing defining an inlet, an outlet, a flow path extending from the inlet to the outlet, and an internal compartment separated from the flow path. The implantable blood pump also has a rotor disposed in the flow path and operable to pump blood from the inlet to the outlet, and a stator disposed in the internal compartment and operable to drive the rotor. The implantable blood pump further has a plurality of sensors including at least two of a current sensor configured to detect a current supplied to the stator, a rotor position sensor configured to detect a position of the rotor relative to the housing, an accelerometer configured to detect an acceleration of the blood pump in at least one direction, and a pressure sensor disposed between the inlet and the outlet and configured to detect a pressure of the blood flowing through the flow path. The controller is connected to the plurality of sensors and includes a signal processing module and at least one of an operator interface module and a pump control module. The signal processing module is configured to receive a data stream from each of the plurality of sensors. The signal processing module is also configured to filter the data streams received from the plurality of sensors and determine at least one of pump operation parameters, heart characteristics, and pump control parameters based on at least two of the filtered data streams, and output at least one of the pump operation parameters, heart characteristics, and pump control parameters to at least one of the operator interface module and the pump control module.

[0008] The present disclosure also relates to a method of operating an implantable blood pump. The blood pump includes a housing that defines an inlet, an outlet, a flow path extending from the inlet to the outlet, and an internal compartment separated from the flow path. The blood pump also includes a rotor disposed within the flow path and operable to pump blood from the inlet to the outlet, and a stator disposed within the internal compartment and operable to drive the rotor. The method includes detecting, using a plurality of sensors, at least two of a current supplied to the stator, a position of the rotor relative to the housing, an acceleration of the blood pump in at least one direction, and a pressure of the blood flowing through the flow path. The method also includes receiving, by a signal processing module of a controller connected to the plurality of sensors, a data stream from each of the plurality of sensors, and filtering, by the controller, the data streams received from the plurality of sensors. The method further includes determining, by the controller, at least one of pump operation parameters, heart characteristics, and pump control parameters based on at least two of the filtered data streams, and outputting at least one of the pump operation parameters, heart characteristics, and pump control parameters from the signal processing module to at least one of an operator interface module and a pump control parameter.

[0009] The present disclosure further relates to an implantable blood pump having an inlet, an outlet, a flow path extending from the inlet to the outlet, and a housing defining an internal compartment separated from the flow path. The implantable blood pump also includes a rotor disposed within the flow path and operable to pump blood from the inlet to the outlet, a stator disposed within the internal compartment and operable to drive the rotor, and a plurality of sensors. The plurality of sensors includes a current sensor configured to detect a current supplied to the stator, a rotor position sensor configured to detect a position of the rotor relative to the housing, an accelerometer configured to detect an acceleration of the blood pump in at least one direction, and a pressure sensor disposed between the inlet and the outlet and configured to detect a pressure of the blood flowing through the flow path. The plurality of sensors is connected to a controller, which receives a data stream from each of the plurality of sensors, filters the data streams received from the plurality of sensors, and determines at least one of a pump operation parameter, a cardiac characteristic, and a pump control parameter based on the filtered data streams.

Brief Description of the Drawings

[0010]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10A

Fig. 10B

Fig. 11

[0011] The present disclosure relates to an implantable blood pump assembly. Embodiments of the implantable blood pump assembly disclosed herein include a plurality of sensors connected to a controller. For example, in some embodiments, the plurality of sensors includes a current sensor, a rotor position sensor, an accelerometer, and a pressure sensor. A signal processing module of the controller receives data streams from each of the plurality of sensors and filters the data streams. In some embodiments, at least one supplemental data stream is generated based on the data streams of the plurality of sensors. For example, the supplemental data stream may include the pressure of the blood flowing out of the blood pump assembly through the outlet. Based on the filtered data streams, the controller determines at least one of pump operation parameters, heart characteristics, and pump control parameters. The pump operation parameters, heart characteristics, or pump control parameters are output to an operator interface module for presentation to an operator and / or output to a pump control module configured to control the blood pump assembly.

[0012] Furthermore, by comparing and combining the data streams, more robust and accurate clinical and operational information can be provided than information based on individual data streams alone. In some embodiments, the accuracy of each data stream is determined based on the comparison results of the data streams, and a quality assessment is assigned to each data stream based on the determined accuracy of the data stream. As a result, the implantable blood pump assembly described herein can provide more accurate and complete information for patient clinical evaluation compared to conventional blood pump assemblies. Additionally, the implantable blood pump assembly operates at least partially autonomously based on the plurality of data streams.

[0013] Referring now to the drawings, FIG. 1 is a diagram of a mechanical circulatory support system 10 implanted in a patient's body 12. The mechanical circulatory support system 10 includes an implantable blood pump assembly 14 that includes a blood pump 16, a ventricular cuff 18, and an outflow cannula 20. The mechanical circulatory support system 10 also includes an external system controller 22 and one or more power sources 24 (e.g., a battery).

[0014] The blood pump assembly 14 can be implemented as, or include, a ventricular assist device (VAD) attached to the apex of the left ventricle, the right ventricle, or both ventricles of the heart 26 as shown. The blood pump assembly 14 is sutured to the heart 26 and attached to the heart 26 via the ventricular cuff 18 that is connected to the blood pump assembly 14. The other end of the blood pump assembly 14 is connected to the ascending aorta or the descending aorta via the outflow cannula 20, whereby the blood pump assembly 14 effectively bypasses blood from the weakened ventricle and propels it into the aorta for circulation through the patient's remaining vascular system. The VAD can include a centrifugal pump (as shown) or an axial flow pump, as described in more detail herein, capable of pumping the total output delivered from the pulmonary circulation to the left ventricle (i.e., up to 10 liters per minute).

[0015] Figure 1 shows a mechanical circulatory support system 10 during battery-powered operation. Communication line 28 connects the implanted blood pump assembly 14 to an external system controller 22 that monitors the operation of the mechanical circulatory support system 10. In the illustrated embodiment, communication line 28 is shown as a drive line that exits through the patient's abdomen 30, but it should be understood that the blood pump assembly 14 may be connected to the external system controller 22 via any suitable communication line including wired communication and / or wireless communication. The system may be powered by one or more power sources 24. The external system controller 22 and the power source 24 are shown outside / externally of the patient's body, but the communication line 28, the external system controller 22, and / or the power source 24 may be partially or fully implanted within the patient's body as separate components or integrally with the blood pump assembly 14.

[0016] Figure 2 is a diagram of an implantable blood pump assembly 100 suitable for use in the mechanical circulatory support system 10 of Figure 1, and the blood pump assembly 100 is shown in an operating position implanted in the patient's body. In the illustrated embodiment, the blood pump assembly 100 is a left ventricular assist blood pump assembly connected to the left ventricle LV of the heart H.

[0017] The blood pump assembly 100 includes a blood pump 102 having a circular pump housing 104 with a first outer surface, i.e., a first outer wall 106, and a second outer surface, i.e., a second outer wall 108. The blood pump assembly 100 further includes an inlet cannula 110 (generally, an inlet conduit), which in the illustrated embodiment extends from the first outer wall 106 of the pump housing 104. As shown in FIG. 2, when the blood pump assembly 100 is implanted in a patient's body, the first outer wall 106 of the pump housing 104 is disposed opposite the patient's heart H, and the second outer wall 108 of the pump housing 104 faces away from the heart H. The inlet cannula 110 extends into the left ventricle LV of the heart H and connects the blood pump assembly 100 to the heart H. The second outer wall 108 of the pump housing 104 has a chamfered edge 109 to avoid irritating other tissues, such as the patient's diaphragm, that may come into contact with the blood pump assembly 100.

[0018] FIG. 3 is a schematic cross-sectional view of the blood pump assembly 100 of FIG. 2. FIG. 4 is a perspective cross-sectional view of the blood pump assembly 100. FIG. 5 is an enlarged view of the blood pump assembly 100. The blood pump assembly 100 further includes a stator 112, a rotor 114, an on-board controller 116, and a plurality of sensors 118 (shown in FIG. 6). In the illustrated embodiment, at least some of the stator 112, the rotor 114, the on-board controller 116, and the plurality of sensors 118 are contained within the pump housing 104. In the illustrated embodiment, the stator 112 and the on-board controller 116 are disposed on the inlet side of the pump housing 104 facing the first outer wall 106, and the rotor 114 is disposed along the second outer wall 108. In other embodiments, the stator 112, the rotor 114, and the on-board controller 116 may be disposed at any suitable location within the pump housing 104 that enables the blood pump assembly 100 to function as described herein. Power is supplied to the operating components (e.g., the stator 112 and the on-board controller 116) of the blood pump assembly 100 from a remote power source by a power cable 120 (shown in FIG. 2).

[0019] The pump housing 104 defines an inlet 122 for receiving blood from a ventricle of the heart (e.g., the left ventricle LV shown in FIG. 2), an outlet 124 for returning the blood to the circulatory system, and a blood flow path 126 extending from the inlet 122 to the outlet 124. The pump housing 104 further defines, for example, an internal compartment 128 separated from the blood flow path 126 by one or more partition walls 130.

[0020] The pump housing 104 also includes an intermediate wall 132 disposed between a first outer wall 106 and a second outer wall 108, and a peripheral wall 134 extending between the first outer wall 106 and the intermediate wall 132. The first outer wall 106, the partition wall 130, the intermediate wall 132, and the peripheral wall 134 cooperate to define an internal compartment 128 that houses the stator 112 and the on-board controller 116.

[0021] In the illustrated embodiment, the pump housing 104 also includes a cap 136 removably attached to the pump housing 104 along the intermediate wall 132. The cap 136 is threaded onto the pump housing 104 in the illustrated embodiment, but in other embodiments, it may be connected to the pump housing 104 using any suitable connection means that allows the blood pump assembly 100 to function as described herein. For example, in some embodiments, the cap 136 is non-removably connected to the pump housing 104, such as by welding. The removable cap 136 includes the second outer wall 108 and a chamfered edge 109 and defines the outlet 124. The cap 136 also defines a volute chamber 138 in fluid communication with the outlet 124 and a rotor chamber 140 within which the rotor 114 is disposed. The cap 136 may be attached to the pump housing 104 using any suitable connection structure. For example, the cap 136 may be engaged with the peripheral wall 134 by threads to seal the cap 136 in engagement with the peripheral wall 134.

[0022] The rotor 114 is disposed within the blood flow path 126, specifically within the rotor chamber 140, and is operable to pump blood from the inlet 122 to the outlet 124 by rotating in response to the electromagnetic field generated by the stator 112. The rotor 114 defines a central opening 142 through which blood flows during operation of the blood pump 102. The rotor 114 includes impeller blades 144 disposed within the volute chamber 138 of the blood flow path 126 and a shroud 146 that covers an end of the impeller blades 144 that faces the second outer wall 108 to assist in directing blood flow into the volute chamber 138.

[0023] In the illustrated embodiment, the rotor 114 includes a permanent magnet 148 that defines the central opening 142. The permanent magnet 148 has a permanent magnet N pole N and a permanent magnet S pole S for combining active and passive magnetic levitation of the rotor 114 and rotation of the rotor 114. During operation, the stator 112 is controlled to drive (i.e., rotate) the rotor and levitate the rotor 114 radially by generating an electromagnetic field that interacts the permanent magnet N pole N and the permanent magnet S pole S of the permanent magnet 148.

[0024] By using any suitable stator 112, the rotor 114 can be rotated. The stator 112 generally includes a plurality of winding structures that generate an appropriate electromagnetic field to rotate and levitate the rotor 114 by interacting with the rotor 114. In the illustrated embodiment, the stator 112 includes a plurality of pole pieces 150 circumferentially arranged at intervals around the partition wall 130. The exemplary blood pump assembly 100 includes six pole pieces 150, two of which are shown in FIG. 3. In other embodiments, the blood pump assembly 100 can include more than six pole pieces, such as four pole pieces, eight pole pieces, or any other suitable number of pole pieces, or less than six pole pieces, that enable the blood pump assembly 100 to function as described herein. In the illustrated embodiment, each of the pole pieces 150 includes a drive coil 152 for generating an electromagnetic field to rotate the rotor 114 and a levitation coil 154 for generating an electromagnetic field to control the radial position of the rotor 114.

[0025] Each of the drive coil 152 and the levitation coil 154 includes a plurality of windings of a conductor wound around the pole piece 150. The drive coil 152 and the levitation coil 154 of the stator 112 are arranged in opposing pairs and are controlled to generate an electromagnetic field that drives the rotor and levitates the rotor 14 in the radial direction by interacting with the permanent magnet S pole and the permanent magnet N pole of the permanent magnet 148. Suitable methods for generating an electromagnetic field to rotate and levitate the rotor 114 are described, for example, in U.S. Patent No. 9,849,224, the entire contents of which are incorporated herein by reference for all purposes. In the illustrated embodiment, the drive coil 152 and the levitation coil 154 are shown as separate coils, but it should be understood that the drive coil 152 and the levitation coil 154 may be implemented as a single coil configured to generate an electromagnetic field for both rotation and radial levitation of the rotor 114.

[0026] The inlet cannula 110 is attached to the pump housing 104 at the inlet 122. As shown in FIG. 4, the pump housing 104 includes an inlet cannula receiving portion 156 that includes a suitable connection structure for connecting the inlet cannula 110 to the pump housing 104. In the illustrated embodiment, the pump housing 104 includes a female threaded sleeve 158 that engages a male thread 160 on the downstream end 162 of the inlet cannula 110 to connect the inlet cannula 110 to the pump housing 104.

[0027] The inlet cannula 110 defines an inlet flow path 164 that supplies blood to the inlet 122 of the pump housing 104. As shown in FIG. 4, in the illustrated embodiment, the inlet cannula 110 extends into the blood flow path 126 defined by the pump housing 104, and the inlet flow path 164 partially overlaps the blood flow path 126.

[0028] The downstream end 162 of the inlet cannula 110 has a reduced cross-sectional area (e.g., as compared to the upstream end of the inlet cannula 110), thereby creating a local region where the blood flow through the inlet flow path 164 and the blood flow path 126 is high speed. Specifically, the cross-sectional area of the inlet flow path 164 gradually and continuously decreases toward the downstream end 162 of the inlet cannula 110 such that the velocity of the blood flowing through the inlet cannula 110 at a constant flow rate increases as the blood flows through the downstream end 162 of the inlet cannula 110. As a result, during operation of the blood pump assembly 100, the reduced cross-sectional area of the downstream end 162 creates a local region where the blood flow through the inlet 122 and the blood flow path 126 is high speed.

[0029] In some embodiments, a portion 172 (shown in FIG. 4) of the internal compartment 128 is sealed from a portion of the internal compartment that may communicate with a fluid (e.g., blood) to inhibit fluid (e.g., blood) ingress into the portion of the internal compartment 128 that houses the electronic devices (e.g., the stator 112 and the on-board controller 116). In the illustrated embodiment, for example, the sensor assembly housing 174 forms a seal with the pump housing 104 to hermetically seal the portion 172 of the internal compartment 128 that houses the electronic devices from the internal cavity defined by the sensor assembly housing 174.

[0030] Referring further to FIG. 6, the plurality of sensors 118 includes at least one pressure sensor 178, a first current sensor 180, a second current sensor 182, an accelerometer 184, and a rotor position sensor 186. The first current sensor 180 and the second current sensor 182 are configured to detect the current supplied to the stator 112. For example, the first current sensor 180 is connected to the drive coil 152 and is configured to measure the current supplied from the power source to the drive coil 152 of the stator 112. The second current sensor 182 is connected to the levitation coil 154 and is configured to measure the current provided from the power source to the levitation coil 154 of the stator 112. In other embodiments, the blood pump assembly 100 may include any suitable current sensor that enables the blood pump assembly 100 to operate as described herein. For example, in some embodiments, the blood pump assembly 100 includes a single current sensor configured to measure both the current provided to the drive coil 152 and the current provided to the levitation coil 154. In some embodiments, the first current sensor 180 and / or the second current sensor 182 are disposed outside the pump housing 104. For example, in some embodiments, the first current sensor 180 and / or the second current sensor 182 may be connected to the external system controller 22 (shown in FIG. 1) and / or the power source 24 (shown in FIG. 1).

[0031] The rotor position sensor 186 is configured to detect the position of the rotor 114 relative to the stator 112. For example, in the illustrated embodiment, the rotor position sensor 186 is a Hall effect sensor that provides an output voltage directly proportional to the strength of the electromagnetic field located between the pole piece 150 and the permanent magnet 148. The rotor position sensor 186 provides the output voltage to the on-board controller 116 as a continuous data stream. The on-board controller 116 continuously tracks the position of the rotor 114 by associating the data stream with the position of the rotor 114 relative to the stator 112. The data stream from the rotor position sensor 186 is used to adjust the position of the rotor 114 by selectively attracting and repelling the permanent magnet S pole and the permanent magnet N pole of the permanent magnet 148, and / or to rotate the rotor 114 within the stator 112 during operation of the blood pump assembly 100.

[0032] In the illustrated embodiment, the blood pump assembly 100 includes two pressure sensors 178 configured to detect the pressure of the blood flowing through the blood flow path 126. For example, as shown in FIGS. 5 and 6, in the illustrated embodiment, each pressure sensor 178 includes a sensing element 188 and a deflectable membrane 190 disposed between the sensing element 188 and the blood flow path 126. In other embodiments, the blood pump assembly 100 may include more than two or fewer than two pressure sensors 178.

[0033] The pressure sensors 178 are arranged such that each of the pressure sensors 178 can detect the pressure of the fluid flowing through the blood flow path 126. For example, in the illustrated embodiment, the pressure sensors 178 are disposed at the interface between the inlet cannula 110 and the pump housing 104, adjacent to the downstream end 162 of the inlet cannula 110. More specifically, the pressure sensors 178 are disposed between the outlet 166 of the inlet cannula 110 and the inlet 168 to the rotor chamber 140.

[0034] The exemplary accelerometer 184 of the exemplary embodiment is attached to the circuit board 170 of the on-board controller 116 and is configured to detect the acceleration of the blood pump assembly 100 in at least one direction. For example, the accelerometer 184 may be a three-axis linear accelerometer configured to measure acceleration in three directions.

[0035] In the illustrated embodiment, the blood pump assembly 100 has an axis 192 around which the rotor 114 rotates. In the illustrated embodiment, the blood flow path 126 extends along the axis 192. The accelerometer is configured to detect the acceleration of the blood pump assembly 100 in a first direction parallel to the axis 192, a second direction perpendicular to the axis 192, and a third direction perpendicular to the axis 192 and perpendicular to the second direction. The accelerometer is configured to provide a data stream indicative of the detected acceleration to the on-board controller 116. In some embodiments, the on-board controller 116 is configured to determine the patient's activity level, the orientation of the blood pump 102, and / or the displacement of the blood pump 102 or the heart wall based on the acceleration in at least one of the first, second, and third directions. In other embodiments, the blood pump assembly 100 may include a plurality of accelerometers 184, and each accelerometer 184 may provide information regarding the acceleration in at least one direction.

[0036] The on-board controller 116 may include one or more modules or devices included within the pump housing 104. The on-board controller 116 can generally include any other processing unit including any suitable computer and / or any suitable combination of computers, and / or processing units that can be communicatively coupled to each other (e.g., the on-board controller 116 can form all or part of a controller network). Thus, the on-board controller 116 can include one or more processors configured to perform various computer-implemented functions (e.g., perform the methods, steps, calculations, etc. disclosed herein), and associated memory devices. As used herein, the term "processor" refers not only to integrated circuits referred to as being included in a computer in the art, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), and other programmable circuits. Further, the memory devices of the on-board controller 116 can generally include, but are not limited to, memory elements such as non-transitory computer-readable media (e.g., random access memory (RAM), read-only memory (ROM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disc read-only memory (CD-ROM), magneto-optical disks (MOD), digital versatile disks (DVD), and / or other suitable memory elements.Such a memory device generally stores computer-readable instructions that, when executed by a processor, configure an on-board controller 116 to perform various functions including, but not limited to, controlling the supply of current to the stator 112, determining pump operation parameters, cardiac characteristics, or waveforms related to pump control parameters, determining or calculating cardiac events or characteristics based on information provided by a plurality of sensors 118 such as heart rate, contractility, end-systolic pressure, end-diastolic pressure, atrial kick pressure, left ventricular contractility, maximum left ventricular pressure, and left ventricular relaxation, adjusting the speed of the rotor 114 based on information provided by one or more of the plurality of sensors 118 and / or the determined cardiac events or characteristics, outputting measurement data to an external controller (e.g., an external system controller 22), and performing various other suitable computer-implemented functions. Further, the memory can be used to store patient-specific parameters that the on-board controller 116 uses to control the patient-specific operating modes of the blood pump assembly 100 and related software modules.

[0037] In the illustrated embodiment, the on-board controller 116 is implemented as various components provided on a circuit board (e.g., a processor and a memory device) for controlling the operation of the blood pump 102 by controlling the power supply to the stator 112 and one or more circuit boards 170 (shown in FIG. 4).

[0038] A communication line (e.g., communication line 28 shown in FIG. 1) connects the blood pump assembly 100 and the on-board controller 116 to an external system controller 22 (shown in FIG. 1) that monitors system operation via various software applications. As noted above, the blood pump assembly 100 itself also includes several software applications executable by the on-board controller 116 for various functions such as controlling the radial lift and / or drive of the rotor 114 of the operating pump assembly 100. Next, the external system controller 22 can be connected to a battery (power supply 24) or a power module (not shown) that connects to an AC outlet. The external system controller 22 can also include an emergency backup battery (EBB) for powering the system (e.g., when the battery is depleted) and a membrane overlay that includes a Bluetooth® function for wireless data communication. An external computer configurable by an operator such as a clinician or patient can be further connected to the circulatory support system 100 to configure the external system controller 22, the embedded blood pump assembly 100 and / or patient-specific parameters, to update the software on the external system controller 22 and / or the embedded blood pump assembly 100, to monitor system operation, and / or as a conduit for system input or output.

[0039] Figure 6 is a schematic diagram of a sensing and control system 200 suitable for use in the mechanical circulatory support system 10 of FIG. 1. The sensing and control system 200 may include, in some embodiments, a controller 202 that may include at least one of an external system controller 22 (shown in FIG. 1) and / or an on-board controller 116 (shown in FIG. 3). The controller 202 includes an operator interface module 204, a pump control module 206, and a sensor processing module 208. In some embodiments, one or more of the operator interface module 204, the pump control module 206, and the sensor processing module 208 are disposed in a computing unit separate from the external system controller 22 and the on-board controller 116.

[0040] The sensing and control system 200 further includes a plurality of sensors 118 including a pressure sensor 178, a first current sensor 180, a second current sensor 182, an accelerometer 184, and a rotor position sensor 186. The plurality of sensors 118 are connected to the controller 202 by appropriate electrical conduits, receive power from the controller 202, and send signals to the controller 202. For example, the signal processing module (sensor processing module 208) of the controller 202 is configured to receive data streams from the pressure sensor 178, the first current sensor 180, the second current sensor 182, the accelerometer 184, and the rotor position sensor 186. Further, the controller 202 generates a supplementary data stream based on the data streams received from the plurality of sensors 118. For example, the controller 202 determines a supplementary data stream indicative of the pressure of the blood flowing out of the blood pump 102 through the outlet 124 based on measurements from at least one of the first current sensor 180 and the pressure sensor 178.

[0041] The signal processing module is configured to filter data streams received from a plurality of sensors 118. For example, some of the data streams include waveform signals, and the signal processing module performs waveform feature extraction on the data streams. During the waveform feature extraction process, the signal processing module determines features of the waveform signals representing measurements such as bearing current, rotor position, blood flow through the blood pump assembly 100, the pressure of the blood exiting the blood pump assembly 100 (e.g., aortic pressure), and the pressure of the blood entering the blood pump assembly 100 (e.g., left ventricular LV pressure). Further, the signal processing module determines the patient's activity level, the orientation of the pump, and the movement of the left ventricular LV based on data streams from the accelerometer and / or other sensors among the plurality of sensors 118.

[0042] In some embodiments, the signal processing module performs spectral analysis on the data streams based on the frequency spectrum. For example, in some embodiments, spectral analysis includes determining features of the data streams, such as the frequency and amplitude content of any periodic signals in the data stream, by applying a fast Fourier transform (FFT) to the data stream. In some embodiments, the FFT may be applied to the accelerometer data stream, and the transformed data stream may indicate frequencies related to the rotor spin speed (rotor speed and its harmonics), along with other vibration signals such as vibrations due to valve closure. The vibration signals provide "heart sounds" (colloquially called "thump thump") that can be interpreted according to known diagnostic techniques. For example, by using changes in the amplitude of the heart sound frequencies, it is also possible to detect the degree of valve opening and diagnose valvular diseases such as aortic valve regurgitation and stenosis.

[0043] Also, the signal processing module can be configured to remove noise or artifacts from the signal and / or adjust waveform parameters based on preset thresholds and ranges. In other words, the signal processing module "cleans up" the raw data stream to provide a filtered data stream that is easier for the controller 202 to use in calculations and / or output.

[0044] The controller 202 is also configured to compare the data stream and / or values determined based on the data stream and determine signal quality parameters for each data stream received from the sensor 118 by the signal processing module. For example, the controller 202 can determine pump operation parameters, heart characteristics, or pump control parameters based on each data stream and compare the determined values to each other to determine the accuracy and reliability of the signal. In some embodiments, the controller 202 determines values that can be independently derived from each data stream, such as heart rate. Based on the comparison, the controller 202 associates a quality assessment with each data stream or sensor 118. For example, if one of the determined values is different from at least one other determined value, the controller 202 identifies which value is more likely to be correct and more likely to have a high quality assessment associated with the data stream used to determine the value. The controller 202 associates a lower quality assessment with the other data streams. In some embodiments, data streams with a lower quality assessment (e.g., a quality assessment below a preset threshold) are excluded from further calculations.

[0045] Furthermore, the controller 202 may be configured to determine at least one of a pump operation parameter, a cardiac characteristic, and a pump control parameter based on the filtered data stream. For example, the controller 202 may determine any of the following based on the filtered data stream: heart rate, cycle timing, support current amplitude, displacement amplitude of the rotor 114, maximum flow rate through the blood pump assembly 100, minimum flow rate through the blood pump assembly 100, average flow rate through the blood pump assembly 100, amplitude of the flow rate through the blood pump assembly 100, maximum rate of change of the flow rate through the blood pump assembly 100, minimum rate of change of the flow rate through the blood pump assembly 100, maximum aortic pressure, minimum aortic pressure, average aortic pressure, maximum rate of change of the aortic pressure, minimum rate of change of the aortic pressure, maximum left ventricular pressure, minimum left ventricular pressure, average left ventricular pressure, maximum rate of change of the left ventricular pressure, minimum rate of change of the left ventricular pressure, maximum left ventricular acceleration, pitch angle of the blood pump assembly 100, yaw angle of the blood pump assembly 100, activity level of the patient, and degree of opening of the aortic valve.

[0046] For example, the controller 202 may be programmed to determine the patient's heart rate by applying a fast Fourier transform to the pressure data collected by the pressure sensor 178 and / or by calculating the time intervals between cardiac cycle detection points that are apparent from the pressure waveform (e.g., the beginning of systole, the end of systole, the beginning of diastole, and / or the end of diastole). The controller 202 may also be programmed to determine any other cardiac characteristics by applying mathematical operations to the data collected by the sensor 118, such as ventricular filling pressure or minimum pressure, maximum pressure or maximum systolic pressure, pressure amplitude (i.e., the difference between the maximum pressure and the minimum pressure), average pressure, contractility (i.e., maximum systolic dP / dt), relaxation (i.e., minimum systolic dP / dt), end-systolic pressure, end-diastolic pressure, atrial kick pressure.

[0047] Furthermore, the controller 202 may determine pump operation parameters, cardiac characteristics, and / or pump control parameters by combining two or more data streams. In some embodiments, the controller 202 combines the data streams to provide a statistically weighted value. In other words, the controller 202 determines the statistical weight of each data stream based on quality assessment, preset criteria, and / or any other appropriate factors, and applies the determined weight to each data stream to calculate a value.

[0048] For example, in some embodiments, the controller 202 determines a heart rate value based on an accelerometer data stream, a flow waveform data stream, and an LV pressure waveform data stream by applying a fast Fourier transform to each data stream. Applying the FFT to the data streams highlights the peaks in the low frequency region of each data stream (e.g., the low frequency region may be in the range of about 0.5 Hz to about 3.0 Hz), and the heart rate value is determined based on each data stream. In some embodiments, the flow waveform data stream may have the highest quality and accuracy assessment of the received data streams, and the heart rate value determined based on the flow waveform data stream may be used as a derived value. For example, the flow waveform data stream may have a higher signal-to-noise ratio and sampling rate than the accelerometer and LV pressure waveform data streams. However, by comparing the derived value with the heart rate values determined based on the accelerometer and LV waveform data streams, the reliability of the derived value is provided. For example, if one or both of the accelerometer and LV pressure waveform data streams provide a heart rate value that matches or is within a predetermined tolerance range of the derived value, the derived value may have a high, i.e., strong, reliability. If one or both of the accelerometer and left ventricular pressure waveform data streams provide a heart rate value outside the predetermined tolerance range of the derived value, the derived value may have a low, i.e., weak, reliability.

[0049] Furthermore, in some embodiments, the controller 202 is configured to determine the operating parameters of the blood pump assembly based on a multivariable algorithm or function that takes into account one or more measured values and the determined cardiac characteristics or events. In some embodiments, for example, the controller 202 is configured to determine a target rotor speed based on a statistically weighted function having one or more of heart rate, minimum ventricular pressure, ventricular pressure amplitude, and maximum dP / dt.

[0050] The signal processing module outputs the determined values to the pump control module 206 and / or the operator interface module 204. The operator interface module 204 presents the values to the operator using the connected input / output device 210. The input / output device 210 can include input devices such as, but not limited to, a keyboard, mouse, touch screen, joystick, throttle, button, switch, and / or other input devices. For example, the input / output device 210 can include output devices such as, but not limited to, a display (e.g., a liquid crystal display (LDC) or an organic light emitting diode (OLED) display), speaker, indicator light, meter, and / or other output devices. In some embodiments, the operator interface module 204 is configured to receive at least one operator input, such as the patient's clinical status, and provide the operator input to the pump control module 206 for use in controlling the operation of the blood pump assembly 100. The patient's clinical status may be a clinical measurement or observation by a medical professional, such as a cardiac feature or medical diagnosis.

[0051] The pump control module 206 controls the operation of the blood pump assembly 100 by using the determined value. Thus, the controller 202 provides at least partial autonomous control or closed-loop control of the blood pump assembly 100 by using the information received from the sensors to modify the operation of the blood pump assembly 100. In some embodiments, the controller 202 provides operation control by using any one of or a combination of the rotational speed of the rotor 114, average VAD flow control, VAD flow amplitude control, minimum left ventricle LV control, left ventricle LV pressure amplitude control, and based on the determined value. For example, in some embodiments, the pump control module 206 is included in the on-board controller 116 and is configured to control the rotational speed of the rotor 114 based on the determined value received from the signal processing module. For example, the on-board controller 116 is operably connected to the stator 112 and is configured to control the operation of the blood pump 102 by controlling the supply of current to the stator 112, thereby controlling the rotation of the rotor 114. The pump control module 206 may be configured to control the rotor 114 in continuous flow operation and / or pulsatile flow operation.

[0052] In some embodiments, for example, the controller 202 is configured to achieve a desired or preset heart characteristic by controlling the operation of the blood pump 102. The controller 202 can periodically or continuously query the sensor 118 and compare the detected or determined value with one or more set points (e.g., pressure set point, flow set point). If the detected or determined value is different from the set value, the controller 202 can adjust the operation of the blood pump assembly 100 to achieve the set value. In some embodiments, the controller 202 is configured to determine whether the difference between the characteristic and the set point exceeds a threshold difference before adjusting the operation of the blood pump assembly 100.

[0053] The setpoint can be established, for example, by operator input from a patient or clinician and stored in the memory device of the controller 202. The setpoint can be a fixed (i.e., time-invariant) setpoint or, alternatively, the set value can be a time-variable setpoint. For example, the pressure setpoint can vary according to the various phases of the cardiac cycle. That is, the pressure setpoint can be defined by a pressure profile that defines the desired or target pressure setpoint at various times or phases of the cardiac cycle. Further, the operator input can include a plurality of setpoints, and the controller 202 can select a setpoint based on the determined operating parameters and / or cardiac characteristics. In some embodiments, the setpoint can include a nominal flow rate setpoint, a nominal rotor speed setpoint, a flow amplitude setpoint, and / or a setpoint for any other suitable operating parameter.

[0054] Furthermore, in some embodiments, the setpoint may be adjusted in real time based on the measurements received from sensor 118 and / or the determined heart events or characteristics. For example, in some embodiments, controller 202 is configured to increase or decrease the pressure setpoint based on the maximum slope of the measured ventricular pressure waveform (dP / dt). The maximum dP / dt is related to the contractility of the left ventricle and can be used to achieve the desired unloading of the left ventricle by adjusting the pressure setpoint and the resulting rotor speed. For example, controller 202 may be configured to increase the pressure setpoint and / or the rotor speed based on the determined maximum dP / dt to increase the unloading of the left ventricle. Additionally, in some embodiments, controller 202 is configured to increase or decrease the pressure setpoint based on the determined heart rate of the patient. For example, an increase in heart rate indicates an increased need for cardiac output (e.g., from exercise), and controller 202 may be configured to increase the pressure setpoint by a corresponding amount. Additionally or alternatively, controller 202 may be configured to increase or decrease the pressure setpoint based on feedback received from accelerometer 184 included in blood pump assembly 100. For example, based on feedback from accelerometer 184, controller 202 determines whether the user of blood pump assembly 100 is exercising or performing strenuous activity and increases the pressure setpoint or the speed of the rotor accordingly.

[0055] In various embodiments, the controller 202 determines specific pump operating conditions and / or patient conditions based on the measurements received from the sensor 118 and controls the blood pump 102 accordingly. For example, Table 1 below is an exemplary correlation table showing how the parameters measured and / or determined from the sensor 118 can be associated with and / or correlated to pump operating conditions and patient conditions. In particular, for the specific parameters listed in the leftmost column, Table 1 shows how a positive (+) or negative (-) deviation from the average or expected value of the parameter correlates with one of the specific pump conditions ("suction"), and / or some of the patient conditions ("arrhythmia", "hypertension", "exercise", "sleep", "recovery").

[0056]

Table 1-1

[0057]

Table 1-2

[0058]

Table 1-3

[0059]

Table 1-4

[0060] In Table 1, the rotor displacement amplitude refers to the average peak-to-peak radial rotor displacement amplitude over a certain period, provided in micrometers (μm). The rotor displacement amplitude is determined based on the data stream from the rotor position sensor 186. The support current amplitude refers to the average peak-to-peak support current amplitude over a certain period, provided in milliamperes (mA). The bearing current amplitude is determined based on the data stream from the current sensor 182. The minimum, average, and maximum flow values refer to the average minimum, average, and maximum flows over a certain period, provided in liters per minute (LPM), respectively. The flow amplitude refers to the average peak-to-peak flow amplitude rate over a certain period, provided in liters per minute. The flow value is determined based on the data stream from the current sensor 180. The minimum, average, and maximum LV pressure values refer to the average minimum, average, and maximum left ventricular pressure values over a certain period, provided in millimeters of mercury (mmHg), respectively. The LV pressure amplitude refers to the average peak-to-peak left ventricular pressure amplitude over a certain period, provided in mmHg. The LV pressure value is determined based on the data stream from the inflow pressure sensor (pressure sensor 178). The maximum LV wall velocity refers to the average peak left ventricular wall velocity during systole over a certain period, provided in millimeters per second. The maximum LV wall velocity is determined based on the data stream from the accelerometer 184. The patient's activity level refers to the overall patient activity level, provided as a percentage of the maximum level indicated as the patient's "exercise" state. The patient's activity level is determined based on the data stream from the accelerometer 184. The minimum, average, and maximum aortic pressures refer to the average minimum, average, and maximum aortic pressures over a certain period, provided in mmHg, respectively. The minimum, average, and maximum aortic pressures are determined based on the data streams from the current sensor 180 and the pressure sensor 178. The aortic pressure amplitude refers to the average peak-to-peak aortic pressure amplitude over a certain period, provided in mmHg. The aortic pressure amplitude is determined based on the data streams from the current sensor 180 and the pressure sensor 178. The heart rate refers to the average heart rate over a certain period, provided in beats per minute.The variability of the heart rate refers to the variability of the average heart rate over a certain period, expressed as a percentage. The systolic percentage refers to the average percentage of the cardiac cycle spent in systole. The heart rate, the variability of the heart rate, and the systolic percentage are determined based on data streams from the rotor position sensor 186, the current sensor 182, the pressure sensor 178, and the accelerometer 184. The LV systolic elastance (contractility) refers to the slope of the LV elastance curve during systole that measures the contractility of the left ventricle, provided in units of mmHg / mL (from the pressure-volume (PV) loop). The left ventricular diastolic elastance refers to the slope of the left ventricular elastance curve during diastole that measures the diastolic stiffness of the left ventricle, provided in units of mmHg / mL (PV loop). The LV filling state is a derived value provided as a percentage, combining the minimum left ventricular pressure and the flow amplitude. The aortic valve flow refers to the estimated total flow through the aortic valve, provided in units of liters per minute. The total cardiac output is provided in units of liters per minute and refers to the estimated total cardiac output. The VAD work share refers to the percentage value of the total hydraulic work (systemic circulation) performed by the assistive artificial heart compared to the left ventricle. The total peripheral vascular resistance refers to the average systemic resistance over a certain period, provided in units of mmHg / liter / minute. The overall working state is a derived value provided as a percentage, combining the patient's activity level, the LV filling state, and the heart rate. The inflow occlusion is the percentage of occlusion or interruption of the inflow (100% represents complete occlusion of the inflow, and 0% represents complete release of the inflow). The outflow occlusion is the percentage of occlusion of the outflow.

[0061] Many of the parameters in Table 1 are derived from two or more measured or determined data streams. For example, the hemodynamic state parameters (left ventricular systolic elastance, left ventricular diastolic elastance, left ventricular filling state, aortic valve flow, total cardiac output, and VAD work share) can be determined based on the left ventricular pressure waveform and the flow waveform. Also, the total peripheral vascular resistance, the overall working state, the inflow occlusion, and the outflow occlusion can be determined based on the left ventricular pressure waveform and the flow waveform.

[0062] As shown in Table 1, by using parameters, pump operating conditions and patient conditions can be indicated. For example, the controller 202 recognizes positive and negative deviations (+ / -) from the average or expected value of each parameter and associates that deviation with one or more conditions in Table 1 listed along the top row. The conditions indicated by "+" are associated with positive deviations from the average or expected value of each parameter. The conditions indicated by "-" are associated with negative deviations from the average or expected value of each parameter.

[0063] In some embodiments, when multiple parameters are associated with a single condition, a value of importance may be assigned to the parameters. The parameters may be weighted based on the value of importance to provide a more accurate indicator of the condition. The value of importance is based on an assessment of the quality of the data feed from the sensor, the determined reliability of the parameter, and / or any other appropriate factor. In such embodiments, the controller 202 may determine the pump operating conditions or patient conditions indicated by the positive and negative deviations by weighting the parameters based on the value of importance. For example, Table 2 below shows a list of exemplary importance assessments of the parameters listed in Table 1 using a scale where 5 represents the highest importance and 1 represents the lowest importance.

[0064]

Table 2-1

[0065]

Table 2-2

[0066]

Table 2-3

[0067] As described above, the controller 202 controls the blood pump 102 based on pump operating conditions and / or patient conditions determined from data feeds received from the plurality of sensors 118. For example, Table 3 below shows an exemplary control scheme executed by the controller 202 to control the blood pump 102. Specifically, Table 3 shows under which conditions the controller 202 increases the pump speed relative to the rotor speed set point ("+") and under which conditions the controller 202 decreases the pump speed relative to the rotor speed set value ("-").

[0068]

Table 3

[0069] Furthermore, in some embodiments, the controller 202 is configured to control the speed of the rotor 114 according to a speed profile that defines a time-variable speed setpoint for the rotor 114. In such embodiments, the controller 202 may be configured to modulate the speed of the rotor 114 for different speed setpoints within a single cardiac cycle of the patient's heart. This type of rotor speed control, also known as "synchronous pulsing," can be performed by the controller 202 in any suitable manner that enables the blood pump assembly 100 to function as described herein. In some embodiments, for example, the controller 202 may be configured to increase the speed of the rotor 114 during systole (known as "co-pulsation") or to decrease the speed of the rotor 114 during systole (known as "counter-pulsation"). In yet other embodiments, the controller 202 may be configured to increase the speed of the rotor 114 over a first period during systole and to decrease the speed of the rotor 114 over a second period during systole. Additionally, rotor synchronous pulsing can be performed by the controller 202 at various intervals. For example, the controller 202 may be configured to modulate the speed of the rotor 114 to different speed setpoints within a single cardiac cycle of the patient's heart or over multiple cardiac cycles of the patient's heart (e.g., over two cardiac cycles).

[0070] In other embodiments, the controller 202 is configured to control the speed of the rotor 114 according to a fixed (i.e., time-invariant) speed setpoint. In such embodiments, the controller 202 may be configured to achieve an average speed equal to the speed setpoint by controlling the speed of the rotor 114. The rotor speed profile and / or setpoint can be established, for example, by operator input from the patient or clinician and stored in a memory device of the controller 202.

[0071] Suitably, the sensing and control system 200 is configured to provide operating parameters for various operating states of the blood pump assembly 100 by combining information from various sensors 118. For example, when the blood pump assembly 100 is operating in a pulsating mode, the current sensors 180, 182 do not provide a continuous data stream, so when the blood pump assembly 100 is in a pulse mode, the controller 202 mainly depends on sensors 118 other than the current sensors 180, 182.

[0072] Furthermore, the controller 202 may switch the operating state based on the information received from the sensors 118. For example, the filtered data stream from the accelerometer 184 indicates that the patient is active, and the controller 202 may change the pulse synchronization process based on the information from the accelerometer 184. In some embodiments, the controller 202 may select a pulse mode of the blood pump assembly 100 (e.g., a co-pulse mode in which the pump speed increases during systole, a counter-pulse mode in which the pump speed decreases during diastole, a combination of co-pulse and counter-pulse, or an asynchronous pulse mode) based on information from multiple sensors 118. Additionally, the controller 202 may select one or more pulse parameters (e.g., amplitude, frequency, duration) based on information from multiple sensors 118.

[0073] As described above, the controller 202 may perform closed-loop speed control of the pump rotor 114 by using one or more of the determined heart events or characteristics. For example, an increase in heart rate, minimum ventricular pressure, or ventricular pressure amplitude generally indicates an increasing need for cardiac output. Thus, in some embodiments, the controller 202 is configured to adjust the speed of the rotor 114 by a corresponding amount when data from at least one of the sensors 118 indicates an increase in heart rate, minimum ventricular pressure, and / or ventricular pressure amplitude.

[0074] Furthermore, in some embodiments, physiological heart function may be examined and / or evaluated by using one or more of the determined heart events or characteristics. For example, left ventricular pressure amplitude (i.e., the difference between the maximum pressure and the minimum pressure) is an indicator that combines both filling pressure and contractility. By using the minimum dP / dt, the relaxation rate of the ventricle can be evaluated and the possibility of fibrosis or electrical conduction problems can be identified. By using the maximum dP / dt, the contractile elastance curve of the ventricle, which is a direct measurement of the functional performance of the left ventricle, can be evaluated. This is used, for example, to detect recovery of the left ventricle and accordingly adjust the target pressure and / or the rotor speed set point stored in the controller 202.

[0075] Figure 7 is an exemplary plot of data that can be collected and output by pressure sensor 178 during operation of blood pump assembly 100. The exemplary plot shows a left ventricular pressure waveform 700 (i.e., pressure vs. time) over a period of about 3 seconds. The signal processing module receives the left ventricular pressure waveform 700, performs filtering operations such as waveform extraction, and then determines one or more values based on the filtered data stream. For example, controller 202 may be configured to determine ventricular filling pressure or minimum pressure by identifying a local minimum pressure value on the pressure waveform within a single phase of the cardiac cycle. An example of a ventricular filling pressure value is identified at point 702 in FIG. 7. Further, controller 202 may be configured to determine maximum systolic pressure by identifying a local maximum pressure value on the pressure waveform within a single phase of the cardiac cycle. An exemplary maximum systolic pressure value is identified at point 704 in FIG. 7. Controller 202 may further be configured to determine the pressure amplitude 706 within a single cardiac phase of the pressure waveform by determining the difference between the maximum pressure 704 and the minimum pressure 702. Controller 202 may further be configured to determine contractility by determining the maximum slope 708 of the pressure waveform during the systolic period of a single cardiac cycle. Controller 202 may also be configured to determine relaxation by determining the minimum slope 710 of the pressure waveform during the systolic period of a single cardiac cycle. Controller 202 may also be configured to determine end-systolic pressure and end-diastolic pressure by identifying pressure values along the pressure waveform at the end of each of the systolic and diastolic periods of the cardiac cycle. Controller 202 may also be configured to determine the atrial kick pressure by identifying the pressure value at a local maximum on the pressure waveform during the diastolic period of a single cardiac cycle (i.e., between the end of the systolic period of the first cardiac cycle and the start of the systolic period of the second cardiac cycle). Controller 202 may be configured to determine or identify various phases (e.g., systolic and diastolic) of the cardiac cycle of the pressure waveform based on, for example, the minimum pressure value, the maximum pressure value, the maximum slope value, and the minimum slope value. For example, controller 202 may be configured to determine that a particular portion of the pressure waveform corresponds to the systolic period of the cardiac cycle by determining or identifying the region on the pressure waveform between the maximum slope and the minimum slope.

[0076] FIG. 8 is an exemplary plot of data that can be collected and output by a plurality of sensors. The exemplary plot shows an acceleration waveform 802, a rotor position waveform 804, a rotor speed waveform 806, a flow waveform 808, and an estimated flow waveform 810. For example, the acceleration waveform 802 is based on data collected by the accelerometer 184. The rotor position waveform 804 is based on data collected by the rotor position sensor 186. The flow waveform 808 is based on values determined using a data stream from one or more sensors 118 such as the first current sensor 180 and the pressure sensor 178. The data shown in the exemplary plot was collected while the controller 202 was operating to synchronize the pulses of the blood pump assembly 100 with the heart pulse using measurements from the current sensors 180, 182. For example, the controller 202 identified when the instantaneous current / flow reading switched between a low value and a high value and changed the operation of the blood pump assembly to accommodate the change. The instantaneous current / flow reading was considered a high value when the instantaneous current / flow reading was above the average flow value and a low value when the instantaneous current / flow reading was below the average flow value. The controller 202 recognized the start of systole when the instantaneous current / flow reading transitioned from a low value to a high value, indicating a change from diastolic flow to systolic flow. Next, the controller 202 operated the blood pump assembly 100 to initiate systole.

[0077] FIG. 9 is another exemplary plot of data that can be collected and output by a plurality of sensors. The exemplary plot shows an acceleration waveform 902, a rotor position waveform 904, a rotor speed waveform 906, a flow waveform 908, and an estimated flow waveform 910. For example, the acceleration waveform 902 is based on data collected by the accelerometer 184. The rotor position waveform 904 is based on data collected by the rotor position sensor 186. The flow waveform 908 is based on values determined using a data stream from one or more sensors 118. The data shown in the exemplary plot was collected while the controller 202 operates to synchronize the pulses of the blood pump assembly 100 with the heart pulse using measurements from an outflow flow sensor disposed external to the blood pump assembly 100.

[0078] FIGS. 10A and 10B are flow diagrams illustrating one embodiment of a method 1000 for operating a blood pump (e.g., blood pump 102) implantable in a patient. In the illustrated embodiment, method 1000 includes a step 1004 of detecting a current supplied to a stator (e.g., stator 112) using a current sensor (e.g., current sensors 180, 182), a step 1006 of detecting a position of a rotor (e.g., rotor 114) relative to a housing (e.g., pump housing 104) using a rotor position sensor (e.g., rotor position sensor 186), a step 1008 of detecting an acceleration of the blood pump in at least one direction using an accelerometer (e.g., accelerometer 184), and a step 1010 of detecting a pressure of blood flowing through a flow path using a pressure sensor (e.g., pressure sensor 178). Method 1000 further includes a step 1012 of receiving a data stream from the current sensor in a signal processing module (e.g., sensor processing module 208) of a controller connected to the plurality of sensors, a step 1014 of receiving a data stream from the rotor position sensor in the signal processing module, a step 1016 of receiving a data stream from the accelerometer in the signal processing module, and a step 1018 of receiving a data stream from the pressure sensor in the signal processing module.

[0079] Method 1000 also includes step 1020 of filtering each of the data streams received in the signal processing module by the controller, and step 1022 of determining, by the controller, at least one of a pump operation parameter, a heart characteristic, and a pump control parameter based on at least two of the filtered data streams. For example, in some embodiments, the step of filtering the data stream includes the step of performing waveform feature extraction on the data stream. The characteristics of the waveform (e.g., amplitude, frequency, wavelength) may indirectly correspond to the operating conditions of the pump and / or the heart characteristics. Therefore, by the controller using one or more waveform features extracted from one or more data streams, a pump operation parameter, a heart characteristic, or a pump control parameter can be determined.

[0080] Method 1000 further includes step 1024 of outputting at least one of a pump operation parameter, a heart characteristic, and a pump control parameter to at least one of an operator interface module (e.g., operator interface module 204) and a pump control module (e.g., pump control module 206) from the signal processing module. The pump control module may control the operation of the pump based on the value received from the signal processing module. For example, in some embodiments, the pump control module controls the rotational speed of the rotor based on the value received from the signal processing module. Also, in some embodiments, the operator interface module may use a display to provide the value received from the signal processing module to the operator.

[0081] In some embodiments, method 1000 further includes generating a supplemental data stream based on at least two of the data streams received by the signal processing module. For example, the signal processing module determines the waveform of the pressure of the blood flowing out of the blood pump through the outlet based on the current supplied to the stator and the pressure of the blood flowing through the flow path. Thus, the supplemental data stream may represent the pressure of the patient's blood flow (e.g., aortic pressure). The supplemental data stream may be filtered and combined or compared with other filtered data streams. Further, the controller may determine at least one of the pump operation parameters, cardiac characteristics, and pump control parameters based on the additional filtered data stream.

[0082] Also, in some embodiments, method 1000 includes comparing the data streams received from each sensor. The data streams are compared by determining cardiac characteristics based on each data stream and comparing the determined cardiac characteristics. For example, the determined values are evaluated to identify outliers (i.e., determined values that are significantly different from at least two other values). Further, by comparing the determined values with directly measured or estimated values, values that are significantly different from the expected and / or measured characteristics of the heart can be identified. For example, in some embodiments, the patient's heart rate is determined based on each data stream. Each determined heart rate is compared with the actual measured value of the patient's heart rate and / or the range of the patient's expected heart rate to confirm whether the data stream is within the preset accuracy range. Additionally or alternatively, by comparing the determined heart rates with each other, it may be confirmed whether any of the data streams has a significantly higher / lower accuracy than the other data streams.

[0083] Furthermore, in some embodiments, method 1000 includes associating a quality assessment with each data stream. For example, the signal processing module assigns a numerical or other value to each data stream based on a point assessment system or a predetermined scale (e.g., a 1-5 scale where 1 is the lowest quality assessment and 5 is the highest quality assessment). Based on the quality assessment, the controller can weight the data streams and may rely more heavily on data streams with higher quality assessments. Additionally, in some embodiments, the controller may ignore data streams having a quality assessment that does not meet a threshold. Further, the controller may provide the quality assessment of one or more data streams for presentation to the operator using an operator interface. In other embodiments, the data streams can be compared and evaluated in any suitable manner. For example, in some embodiments, the signal processing module can compare and evaluate the data streams based on characteristics of the data streams such as signal strength.

[0084] FIG. 11 is a flow diagram showing an exemplary data flow and processing of data collected by sensors and processed by a controller (e.g., controller 202 shown in FIG. 6) during operation of an implantable blood pump (e.g., blood pump 102) of a patient. In the illustrated embodiment, the data feeds are provided by a current sensor 2002, a rotor drive current sensor 2004, an LV pressure sensor 2006, and an accelerometer 2008. The accelerometer 2008 includes a Z-acceleration component 2010, a Y-acceleration component 2012, and an X-acceleration component 2014.

[0085] Data feeds from sensors (current sensor 2002, rotor drive current sensor 2004, LV pressure sensor 2006, and accelerometer 2008) are converted and / or filtered to extract a plurality of parameters. For example, the data feed from current sensor 2002 undergoes conversion of bearing current 2016 and rotor radial position calculation 2018 to provide bearing current data and rotor radial position data respectively. The resulting bearing current data and rotor radial position data each undergo bearing current waveform feature extraction 2028 and rotor position waveform feature extraction 2030. By using bearing current waveform feature extraction 2028, various parameters 2044 including heart rate and cycle timing, and bearing current amplitude can be determined or extracted. Similarly, by using rotor position waveform feature extraction 2030, various parameters 2046 including heart rate and cycle timing (e.g., as redundant values), and bearing displacement amplitude can be determined.

[0086] Furthermore, rotor speed 2020 is calculated based on data feeds from current sensor 2002 and / or rotor drive current sensor 2004. For example, the controller receives one or more data streams such as the displacement and angular position of the rotor, and based on the data stream, determines the amount of drive current and bearing current to provide to the rotor. The provided bearing current and drive current are measured by one or more current sensors 2002. The measured drive current is directly related to rotor speed 2020. Thus, the calculated rotor speed 2020 can be determined based on the data feed from rotor drive current sensor 2004. The calculated rotor speed 2020 is used to calculate the VAD flow value 2022. The resulting VAD flow value undergoes VAD flow waveform extraction 2032, and by using this, various parameters 2048 including, but not limited to, for example, heart rate and cycle timing (e.g., as redundant values), maximum, minimum, and average flow (Q) (e.g., liters per minute), flow amplitude (e.g., liters per minute), and minimum and maximum gradients (dQ / dt) of the flow waveform can be determined or extracted.

[0087] Furthermore, the calculated rotor speed 2020 can be used in combination with the data feed from the LV pressure sensor 2006 to calculate the aortic pressure value 2024. The obtained aortic pressure value is subjected to aortic pressure (AOP) waveform extraction 2034 and, by using this, various parameters 2050 can be determined or extracted, such as, but not limited to, for example, heart rate and cycle timing (e.g., as redundant values), maximum, minimum, and average aortic pressure values (e.g., in mmHg), aortic pressure amplitude (e.g., in mmHg), and minimum and maximum gradients of the aortic pressure waveform (dAOP / dt).

[0088] Furthermore, the calculated VAD flow value 2022 can be used in combination with the data feed from the LV pressure sensor 2006 to calculate the left ventricle (LV) pressure value 2026. The obtained LV pressure value is subjected to LV pressure (LVP) waveform extraction 2036 and, by using this, various parameters 2052 can be determined or extracted, such as, but not limited to, for example, heart rate and cycle timing (e.g., as redundant values), maximum, minimum, and average LV pressure values (e.g., in mmHg), LV pressure amplitude (e.g., in mmHg), and minimum and maximum gradients of the LV pressure waveform (dLVP / dt).

[0089] In the illustrated embodiment, the data feeds from the Z - acceleration component 2010, Y - acceleration component 2012, and X - acceleration component 2014 are subjected to a feature extraction process to determine additional parameters. For example, the data feed from the Z - acceleration component 2010 is subjected to the process of wall motion feature extraction 2038 and, by using this, various parameters 2054 can be determined or extracted, such as, but not limited to, for example, heart rate and cycle timing (e.g., as redundant values), and maximum LV acceleration (e.g., in mm / sec / sec).

[0090] Furthermore, in the illustrated embodiment, data feeds from the Z-acceleration component 2010, the Y-acceleration component 2012, and the X-acceleration component 2012 are combined in the pump direction determination function 2040 to determine the direction of the blood pump 102. The pump direction determination function 2040 can be used to determine or extract various parameters 2056 such as the pitch angle of the blood pump 102 and the yaw angle of the blood pump 102.

[0091] Furthermore, in the illustrated embodiment, data feeds from the Y-acceleration component 2012 and the X-acceleration component 2012 are combined in the patient activity level determination function 2042 to determine the patient activity level 2058.

[0092] Also, by combining two or more of the extracted parameters, combined parameters 2060 and / or signal quality criteria can be provided. The combined parameters 2060 can include, but are not limited to, for example, heart rate, cardiac cycle variation, cardiac cycle contraction rate, minimum flow rate through the blood pump assembly 100, maximum flow rate through the blood pump assembly 100, average flow rate through the blood pump assembly 100, flow rate amplitude through the blood pump assembly 100, maximum rate of change of flow rate through the blood pump assembly 100, minimum rate of change of flow rate through the blood pump assembly 100, maximum aortic pressure, minimum aortic pressure, average aortic pressure, aortic pressure amplitude, maximum rate of change of aortic pressure, minimum rate of change of aortic pressure, maximum left ventricular pressure, minimum left ventricular pressure, average left ventricular pressure, left ventricular pressure amplitude, maximum rate of change of left ventricular pressure, minimum rate of change of left ventricular pressure, maximum left ventricular acceleration, pitch angle of the blood pump assembly 100, yaw angle of the blood pump assembly 100, and patient activity level.

[0093] Furthermore, the clinical condition 2062 of one or more patients can be determined based on the combined parameter 2060. The clinical condition 2062 can include, but is not limited to, for example, LV systolic elastance (contractility), LV diastolic elastance, LV relaxation constant, LV filling state, aortic valve flow rate, total cardiac output, VAD work share, total peripheral vascular resistance, aortic compliance, the overall working state of the patient, inflow occlusion, and outflow occlusion.

[0094] Although specific steps of the exemplary method are numbered, such numbers do not indicate that the steps must be performed in the order listed. Thus, unless the description specifically requires such an order, specific steps need not be performed in the exact order in which they are presented. These steps may be performed in the order listed or in another suitable order.

[0095] As described herein, the implantable blood pump assembly of the present disclosure provides several advantages over conventional VAD designs. For example, embodiments of the implantable blood pump assembly disclosed herein include a plurality of sensors connected to a controller. By combining and / or comparing data streams from the plurality of sensors, the blood pump assembly provides a wider range of information and more reliable information than conventional systems. Also, the controller can determine and provide information related to the signal accuracy of the plurality of sensors that can enhance the operator's confidence in the accuracy and reliability of the system. Further, the controller ensures that accurate information is used to operate the blood pump assembly by determining a statistically weighted value based on the comparison results of information from the plurality of sensors. Additionally, the implantable blood pump assembly can operate at least partially autonomously by using the information provided by the plurality of sensors and the closed-loop control of the controller connected to the plurality of sensors.

[0096] The embodiments and examples disclosed in this specification are described with reference to specific embodiments, but these embodiments and examples should be understood as merely illustrative of the principles and applications of the present disclosure. Therefore, it should be understood that numerous modifications can be made to the exemplary embodiments and examples, and other configurations can be devised without departing from the spirit and scope of the present disclosure as defined by the claims. Accordingly, this application is intended to cover modifications and variations of these embodiments and their equivalents.

[0097] This written description uses examples to describe the disclosure, including the best mode, and enables those skilled in the art to practice the disclosure, including the creation and use of any device or system and the execution of any incorporated method. The patentable scope of the present disclosure is defined by the claims and includes other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ in wording from the claims, or if they include equivalent structural elements that do not differ substantially from the wording of the claims.

Claims

1. A circulatory support system comprising an implantable blood pump and a controller, wherein the blood pump includes a housing defining an inlet, an outlet, a flow path extending from the inlet to the outlet, and an internal compartment separated from the flow path, a rotor disposed in the flow path and operable to pump blood from the inlet to the outlet, a stator disposed in the internal compartment and operable to drive the rotor, and a plurality of sensors, wherein the plurality of sensors includes at least two of a current sensor configured to detect a current supplied to the stator, a rotor position sensor configured to detect a position of the rotor relative to the housing, an accelerometer configured to detect an acceleration of the blood pump in at least one direction, and a pressure sensor disposed between the inlet and the outlet and configured to detect a pressure of blood flowing through the flow path; the controller is connected to the plurality of sensors and includes a signal processing module and at least one of an operator interface module and a pump control module, wherein the signal processing module receives a data stream from each of the plurality of sensors, filters the data streams received from the plurality of sensors, assigns a statistical weight to each of the filtered data streams, determines cardiac characteristics based on at least two of the filtered data streams to which the respective assigned statistical weights are applied, Output the statistically weighted value for the cardiac characteristic to at least one of the operator interface module and the pump control module. For each of the data streams received from the plurality of different types of sensors included in the blood pump, the controller is configured to determine a cardiac characteristic based on the data stream, compare the determined cardiac characteristics with each other, and associate each of the data streams with a quality assessment based on the comparison result of the determined cardiac characteristics. A circulatory support system. **Claim 2** The circulatory support system according to claim 1, wherein the controller is configured to determine a signal quality parameter for each of the data streams received by the signal processing module. **Claim 3** The controller includes a pump control module. The circulatory support system according to claim 1, wherein the pump control module is configured to receive the cardiac characteristic from the signal processing module and control the operation of the implantable blood pump based on the cardiac characteristic. **Claim 4** The accelerometer is configured to detect the acceleration of the blood pump in a first direction, a second direction, and a third direction. The circulatory support system according to claim 1, wherein the controller is configured to determine a patient's activity level based on the acceleration in at least one of the first direction, the second direction, and the third direction. **Claim 5** The controller is configured to generate a supplementary data stream based on the data streams received from the current sensor and the pressure sensor. The circulatory support system according to claim 1, wherein the supplementary data stream includes the pressure of the blood flowing out of the implantable blood pump through the outlet. **Claim 6** The controller is configured to determine the statistical weight for the filtered data stream to which the statistical weight is applied, based on the quality evaluation associated with each of the data streams. The circulatory support system according to claim 1.

7. The controller includes the operator interface module, The operator interface module is configured to display the cardiac characteristics. The circulatory support system according to claim 1.

8. The controller includes the operator interface module and the pump control module, The operator interface module is configured to receive at least one operator input related to the patient's clinical condition and provide the operator input to the pump control module, The pump control module is configured to control the operation of the blood pump based on the operator input and the cardiac characteristics. The circulatory support system according to claim 1.

9. A method of operating an implantable blood pump including a housing defining an inlet, an outlet, a flow path extending from the inlet to the outlet, and an internal compartment separated from the flow path, a rotor disposed in the flow path and operable to pump blood from the inlet to the outlet, and a stator disposed in the internal compartment and operable to drive the rotor, the method comprising: Detecting at least two of the current supplied to the stator, the position of the rotor relative to the housing, the acceleration of the blood pump in at least one direction, and the pressure of the blood flowing through the flow path using a plurality of sensors; Receiving, at a signal processing module of a controller connected to the plurality of sensors, data streams from each of the plurality of sensors; The step of filtering the data stream received from the plurality of sensors by the controller; The step of assigning a statistical weight to each of the filtered data streams; The step of determining cardiac characteristics by the controller based on at least two of the filtered data streams to which the respectively assigned statistical weights are applied; The step of outputting a statistically weighted value for the cardiac characteristics to at least one of the operator interface module and the pump control module from the signal processing module; For each of the data streams received from the plurality of different types of sensors included in the blood pump, the step of determining cardiac characteristics based on the data stream; The step of comparing the determined cardiac characteristics; The step of associating each of the data streams with quality assessment based on the comparison result of the determined cardiac characteristics; A method comprising.

10. Further comprising the step of generating a supplementary data stream based on the current provided to the stator and the pressure of the blood flowing through the flow path, The supplementary data stream includes the pressure of the blood flowing out of the blood pump, and the method according to claim 9.

11. The step of determining the cardiac characteristics includes the step of determining the cardiac characteristics based on the filtered data stream and the supplementary data stream, and the method according to claim 10.

12. The method according to claim 9, further comprising the step of determining a signal quality parameter for each of the data streams received by the signal processing module.

13. The method according to claim 9, further comprising the step of adjusting a set point of the blood pump based on the cardiac characteristics. The method according to claim 9, wherein the step of determining the cardiac characteristics includes a step of determining the heart rate of the patient. Claim 15 wherein the data stream received from the plurality of sensors is a waveform signal, The method according to claim 9, wherein the step of filtering the data stream received from the plurality of sensors includes a step of performing feature extraction of waveforms on the data stream.

Images