Portable ventricular assist system with multi-channel optical pressure sensor

Abstract

The portable ventricular assist system may include a heart pump and at least one hardware controller. The heart pump may include a rotor, a motor configured to drive rotation of the rotor at one or more speeds, a first optical pressure sensor configured to detect a first pressure signal, and a second optical pressure sensor configured to detect a second pressure signal. The at least one hardware controller may include a primary power source, a secondary power source, and at least one light-emitting diode (LED) coupled to the first optical pressure sensor via at least one first optical fiber and to the second optical pressure sensor via at least one second optical fiber. The at least one hardware controller may further include at least one hardware processor configured to determine a differential pressure based at least in part on the first pressure signal and the second pressure signal.

Description

[Technical Field]

[0001] The present disclosure relates to a portable ventricular assist system. [Background technology]

[0002] Fluid pumps, such as blood pumps, are used in the medical field for a wide range of applications and purposes. An intravascular blood pump is a pump that can be advanced through a patient's vasculature, i.e., veins and / or arteries, to a location within the patient's heart or anywhere within the patient's circulatory system. For example, an intravascular blood pump can be inserted via a catheter and positioned to span a heart valve. The intravascular blood pump is typically located at the end of the catheter. Once in position, the pump can be used to assist the heart and pump blood through the circulatory system, thus temporarily reducing the workload on the patient's heart and allowing the heart to recover after a heart attack, for example. An exemplary intravascular blood pump is available from ABIOMED, ​​Inc. (Danvers, MA) under the trademark Impella® heart pump.

[0003] Such pumps can be positioned within a chamber of the heart, such as the left ventricle, to assist the heart. In this case, the blood pump can be inserted via the femoral artery using a hollow catheter and introduced to and into the left ventricle of the patient's heart. From this position, the blood pump inlet draws in blood and the blood pump outlet ejects blood into the aorta. In this way, the function of the heart can be replaced, or at least assisted, by the operation of the pump.

[0004] Intravascular blood pumps are typically connected to respective external heart pump controllers that control the heart pump, such as motor speed, and collect and display operational data about the blood pump, such as cardiac signal levels, battery temperature, blood flow rate, and tubing integrity. An exemplary heart pump controller is available from ABIOMED, ​​Inc. under the trade name "Automated Impella Controller®." If an operational data value exceeds a predetermined value or range, for example, if a leak, suction, and / or pump malfunction is detected, the controller issues an alarm. The controller may include and / or be coupled to a video display screen on which a graphical user interface configured to display the operational data and / or alarm is displayed. Summary of the Invention [Means for solving the problem]

[0005] Described herein are systems and methods for a portable heart pump system including a multi-channel optical pressure sensor. The multi-channel optical pressure sensor, in some embodiments, may be incorporated into the heart pump of the portable heart pump system. When incorporated into the portable heart pump system, the multi-channel optical pressure sensor may be used to sense differential pressure across an aortic valve or the like when the heart pump is positioned within a patient's heart. The differential pressure measurements may be used, for example, to calculate the blood flow rate through the heart pump during its operation.

[0006] In some embodiments, a portable ventricular assist system is provided. The portable ventricular assist system includes a heart pump comprising a rotor, a motor configured to drive rotation of the rotor at one or more speeds, a first optical pressure sensor configured to detect a first pressure signal, a second optical pressure sensor configured to detect a second pressure signal, and at least one hardware controller. The at least one hardware controller comprises a primary power source, a secondary power source, at least one light-emitting diode (LED) coupled to the first optical pressure sensor via at least one first optical fiber and to the second optical pressure sensor via at least one second optical fiber, and at least one hardware processor configured to determine a differential pressure based at least in part on the first pressure signal and the second pressure signal.

[0007] In one aspect, the portable ventricular assist system further includes a connector configured to connect to the heart pump and the at least one hardware controller. The connector includes at least one electrical connection for connecting a primary power source and / or a secondary power source to the motor and at least one optical connection for connecting at least one LED to the first optical pressure sensor and the second optical pressure sensor. In one aspect, the at least one hardware controller further includes a bus system configured to manage power provided to the motor by the primary power source and / or the secondary power source. In one aspect, the bus system is configured to automatically switch power provided from the primary power source to the secondary power source when the state of charge is below a threshold amount.

[0008] In one aspect, the portable ventricular assist system further includes at least one indicator LED configured to indicate a current state of charge of the primary power source and / or the secondary power source. In one aspect, the portable ventricular assist system further includes communication circuitry configured to provide information to a computing device for display, the information including one or more quantities associated with operation of the heart pump. In one aspect, the one or more quantities include a motor current amount associated with operation of the heart pump. In one aspect, the one or more quantities include one or more physiological quantities associated with the patient while the heart pump is in operation. In one aspect, the one or more physiological quantities include a differential pressure measurement across the patient's aortic valve. In one aspect, the communication circuitry is configured to provide the information to the computing device wirelessly.

[0009] In some embodiments, a multi-channel optical pressure sensor is provided that includes: at least one light emitting diode (LED), a plurality of sensors including a first sensor coupled to the at least one LED via at least one first optical fiber and a second sensor coupled to the at least one LED via at least one second optical fiber, a detector module coupled to the first sensor and the second sensor, the detector module including at least one lens and an image sensor configured to sense light received from the at least one lens, and at least one hardware processor configured to determine a first pressure measured at the first sensor and a second pressure measured at the second sensor based at least in part on the light sensed by the image sensor.

[0010] In one aspect, the at least one LED comprises a first LED configured to generate a first light having a first spectrum and a second LED configured to generate a second light having a second spectrum. In one aspect, the first spectrum has a peak wavelength in a range of 550-600 nm, and the second spectrum has a peak wavelength in a range of 800-900 nm. In one aspect, the first spectrum has a peak wavelength in a range of 590-610 nm, and the second spectrum has a peak wavelength in a range of 820-850 nm. In one aspect, the first spectrum has a peak wavelength that is 4 / 5 of the peak wavelength of the second spectrum. In one aspect, the first LED and / or the second LED are smaller than 1 mm. In one aspect, the first LED and / or the second LED are phosphor-converted LEDs. In one aspect, the at least one LED comprises a single LED having a broad spectrum.

[0011] In one aspect, the sensor further includes a first optical element disposed between the at least one LED and the plurality of sensors. The first optical element is configured to receive the first light and the second light and output a third light and a fourth light, each of the third light and the fourth light having a third spectrum. In one aspect, the sensor further includes a second optical element coupled to the first optical element and the first sensor and detector module, and a third optical element coupled to the first optical element and the second sensor and detector module. In one aspect, the second optical element is configured to provide the first reflected light from the first sensor to the detector module, and the third optical element is configured to provide the second reflected light from the second sensor to the detector module.

[0012] In one aspect, the at least one lens comprises a plano lens. In one aspect, the plano lens comprises a set of D-shaped lenses with curved edges facing each other. In one aspect, the at least one lens is configured to reduce spherical aberration in the light received from the first sensor and the second sensor. In one aspect, the detector module further comprises a Fizeau interferometer arranged between the at least one lens and the image sensor. In one aspect, the image sensor comprises a two-dimensional image sensor. In one aspect, the at least one lens and the Fizeau interferometer are configured to collectively project the light received from the first sensor and the second sensor as two lines onto the two-dimensional image sensor. In one aspect, the two lines are two parallel lines. In one aspect, each of the two lines on the two-dimensional image sensor comprises an interference fringe, and determining the first pressure measured at the first sensor and the second pressure measured at the second sensor based at least in part on the light sensed by the image sensor includes determining the first pressure and the second pressure based on the corresponding interference fringes.

[0013] In some embodiments, a circulatory assist device is provided that includes a rotor, a motor configured to drive rotation of the rotor at one or more speeds, a first optical pressure sensor configured to detect a first pressure signal, a second optical pressure sensor configured to detect a second pressure signal, and at least one hardware processor configured to determine a differential pressure signal based at least in part on the first pressure signal and the second pressure signal.

[0014] In one aspect, the at least one hardware processor is further configured to determine a flow rate through the circulatory assist device based at least in part on the differential pressure signal. In one aspect, the circulatory assist device further includes a first light-emitting diode (LED) coupled to the first and second optical pressure sensors, the first LED configured to generate first light having a first spectrum, and a second LED coupled to the first and second optical pressure sensors, the second LED configured to generate second light having a second spectrum. In one aspect, the first spectrum has a peak wavelength in a range of 550-600 nm, and the second spectrum has a peak wavelength in a range of 800-900 nm. In one aspect, the first spectrum has a peak wavelength in a range of 590-610 nm, and the second spectrum has a peak wavelength in a range of 820-850 nm. In one aspect, the first spectrum has a peak wavelength that is 4 / 5 of the peak wavelength of the second spectrum. In one aspect, the first LED and / or the second LED are smaller than 1 mm.In one aspect, the first LED and / or the second LED are phosphor-converted LEDs.

[0015] In one aspect, the circulation assist device further comprises a first optical element arranged to receive the first light and the second light and output a third light and a fourth light, each of the third lights having a third spectrum, the third light being provided to the first optical pressure sensor and the fourth light being provided to the second optical pressure sensor. In one aspect, the circulation assist device further comprises a second optical element coupled to the first optical element and the first optical pressure sensor, and a third optical element coupled to the first optical element and the second optical pressure sensor. In one aspect, the circulation assist device further comprises a detector module, the second optical element configured to provide the first reflected light from the first optical pressure sensor to the detector module, and the third optical element configured to provide the second reflected light from the second optical pressure sensor to the detector module.

[0016] In one aspect, the circulation assist device further includes a detector module coupled to the first and second optical pressure sensors. The detector module includes at least one lens and an image sensor configured to sense light received from the at least one lens. In one aspect, the at least one lens includes a plano lens. In one aspect, the plano lens includes a set of D-shaped lenses having curved edges facing each other. In one aspect, the at least one lens is configured to reduce spherical aberration in the light received from the first and second optical pressure sensors.

[0017] In one aspect, the detector module further includes a Fizeau interferometer arranged between the at least one lens and the image sensor. In one aspect, the image sensor includes a two-dimensional image sensor. In one aspect, the at least one lens and the Fizeau interferometer are configured to collectively project light received from the first optical pressure sensor and the second optical pressure sensor as two lines onto the two-dimensional image sensor. In one aspect, the two lines are two parallel lines. In one aspect, each of the two lines on the two-dimensional image sensor includes an interference pattern, and the at least one hardware processor is further configured to determine a first pressure measured at the first optical pressure sensor and a second pressure measured at the second optical pressure sensor based at least in part on the light sensed by the image sensor by determining the first pressure and the second pressure based on the corresponding interference pattern, and determining a differential pressure signal based at least in part on the first pressure signal and the second pressure signal includes determining a differential pressure signal based on the first pressure and the second pressure. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1A shows an illustrative circulatory assist device that may be used in accordance with some embodiments.

[0019] [Figure 1B]FIG. 1B illustrates the circulatory assist device of FIG. 1A positioned within a patient's heart.

[0020] [Figure 1C] FIG. 1C illustrates a ventricular assist system including the circulatory assist device of FIG. 1A.

[0021] [Figure 2] FIG. 2 illustrates a circulatory assist device including a multi-channel optical pressure sensor, according to some embodiments.

[0022] [Figure 3] FIG. 3 illustrates components of a multi-channel optical pressure sensor system, according to some embodiments.

[0023] [Figure 4] FIG. 4 schematically illustrates a detector module for a multi-channel optical pressure sensor system, according to some embodiments.

[0024] [Figure 5] FIG. 5 illustrates a schematic process for generating interference fringes using a single channel optical pressure sensor system.

[0025] [Figure 6A] FIG. 6A illustrates the spectrum (top) and interference fringe signal (bottom) of a broadband white light source that may be used in the single-channel optical pressure sensor system of FIG.

[0026] [Figure 6B] FIG. 6B illustrates the spectrum (top) and interference fringe signal (bottom) of a dual LED light source that may be used in a multi-channel optical pressure sensor system, according to some embodiments.

[0027] [Figure 7]7A illustrates a display of an interference fringe signal recorded using a two-dimensional image sensor of a multi-channel optical pressure sensor system, according to some embodiments. FIG. 7B illustrates an interference fringe signal extracted from the image sensor data shown in FIG. 7A.

[0028] [Figure 8] FIG. 8 schematically illustrates a portable ventricular assist system, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0029] (Detailed explanation) Circulatory assist devices (also referred to herein as "heart pumps" or simply "pumps") may include percutaneous catheter-based devices that provide hemodynamic support to a patient's heart. Ventricular assist systems may desirably be portable so that patients can freely move about and continue to perform their daily activities while having the heart pump inserted within the patient's heart. As described in further detail herein, some existing ventricular assist systems include a heart pump configured to be positioned within the patient's heart and a controller coupled to the heart pump and configured to provide power to the heart pump and control one or more operational aspects of the heart pump (e.g., pump speed). In addition, the controller may be configured to measure one or more quantities associated with heart pump operation. For example, the controller may be configured to measure quantities associated with heart pump operation, such as motor current associated with motor operation. The controller may also be configured to measure one or more physiological quantities associated with the patient while the heart pump system is operating. For example, measured physiological quantities may include, but are not limited to, pressure measurements within the aorta and / or left ventricle so that a differential pressure across the aortic valve can be determined. In a ventricular assist system that includes only a single pressure sensor, the differential pressure across the aortic valve can be indirectly estimated from the single pressure sensor signal (e.g., located in the aorta) and the heart pump motor current. To facilitate portability, the controller of the ventricular assist system should be small, lightweight, and / or designed for low-power operation to conserve battery power. Some embodiments of the technology described herein provide a portable ventricular assist system that incorporates a portable (e.g., wearable) controller that couples to an implanted heart pump.

[0030] As will be appreciated, for a heart pump to function properly, it should be correctly positioned within a patient's heart, with the pump's inlet portion located within the left ventricle and the pump's outlet portion located within the aorta, thereby spanning the aortic valve of the patient's heart. As shown in FIG. 1A , heart pump 110 may include a pigtail 111, an inlet area 112, a cannula 113, a pressure sensor 114, an outlet area 115, a motor housing 116, and / or a catheter tube 117. The pigtail 111 may assist in stabilizing heart pump 110 within the patient's heart. It should be appreciated that some embodiments of heart pump 110 may not include pigtail 111, and heart pump 110 may be stabilized in other ways or at all. During operation, blood may be drawn into one or more openings in inlet area 112, directed through cannula 113, and expelled through one or more openings in outlet area 115 by a motor (not shown) disposed within motor housing 116. In some implementations, pressure sensor 114 may include a flexible membrane integrated into cannula 113. One side of pressure sensor 114 may be exposed to blood pressure on the outside of cannula 113, and the other side may be exposed to blood pressure inside cannula 113. In some such implementations, pressure sensor 114 may generate an electrical signal proportional to the difference between the pressure outside and inside cannula 113. In some implementations, pressure sensor 114 may include an optical pressure sensor. Catheter tubing 117 may provide one or more fluid and / or electrical connections between heart pump 110 and one or more other devices of the ventricular assist system, an example of which is shown in FIG. 1C.

[0031] 1B , the heart pump 110 may be positioned within the patient's heart 120. For example, the heart pump 110 may be percutaneously inserted via the femoral artery 122, into the ascending aorta 124, across the aortic valve 126, and into the left ventricle 128. In other implementations, the heart pump may be percutaneously inserted via the axillary artery 123, into the ascending aorta 124, across the aortic valve 126, and into the left ventricle 128. In other implementations, the heart pump may be inserted directly into the ascending aorta 124, across the aortic valve 126, and into the left ventricle 128. During operation, the heart pump 110 may take in blood from the left ventricle 128 and eject blood into the ascending aorta 124. As a result, the blood pump 110 may perform a portion of the work normally performed by the patient's heart 120. The hemodynamic effects of a heart pump can include improved coronary blood flow resulting in increased cardiac output, decreased left ventricular end-diastolic pressure, pulmonary capillary wedge pressure, myocardial work, and oxygen consumption.

[0032] As shown in FIG. 1C , heart pump 110 may form part of ventricular assist system 100. Ventricular assist system 100 may also include controller 130 (e.g., an Automated Impella Controller®, referred to herein as “AIC” from ABIOMED, ​​Inc., Danvers, Mass.), display 140, purge subsystem 150, connector cable 160, plug 170, and repositioning unit 180. As shown, controller 130 may include display 140. Controller 130 monitors and controls the operation of heart pump 110. During operation, purge subsystem 150 may be configured to deliver purge fluid to heart pump 110 through catheter tubing 117 to prevent blood from entering a motor (not shown) within motor housing 116. In some implementations, the purge fluid is a glucose solution (e.g., 5% glucose in water with 25 or 50 IU / mL heparin). A connector cable 160 may provide an electrical connection between the heart pump 110 and the controller 130. A plug 170 may connect the catheter tubing 117, the purge subsystem 150, and the connector cable 160. In some implementations, the plug 170 includes a storage device (e.g., memory) configured to store operating parameters, for example, to facilitate transfer of the patient to another controller, if needed. A repositioning unit 180 may be used to reposition the heart pump 110 within the patient's heart.

[0033] In some embodiments, one or more aspects of the controller 130 are configured to support the portable ventricular assist system 100. For example, existing controllers may be configured to plug into a standard wall outlet and provide power to the heart pump 110, whereas controllers 130 designed to be portable may additionally or alternatively be configured to include one or more batteries (e.g., rechargeable batteries) configured to provide power to the motor of the heart pump 110 via a connector cable 160. While including multiple batteries within the controller 130 may increase the weight of the controller, in some embodiments, it is important for the portable ventricular assist system to include a secondary power source in the unlikely event that the primary power source fails or becomes deeply discharged and is unable to provide sufficient power to the heart pump. In some embodiments, the controller 130 may be configured to automatically switch to using the secondary power source when the primary power source has a charge level below a certain charge level (e.g., 10%) to ensure continued operation of the heart pump. In some embodiments, the primary power source and / or secondary power source may be rechargeable and / or removable, for example, to facilitate charging. For example, one or more batteries may be incorporated into a battery pack that is attachable / removable to / from controller 130. In some embodiments, controller 130 includes multiple ports to which battery packs may be coupled. The primary and secondary power sources may be incorporated into a single battery pack or may be provided using separate battery packs. In some embodiments, controller 130 may be configured to include one or more light sources (e.g., LEDs) configured to indicate the current charging status of the primary and / or secondary power sources.

[0034] As described herein, other aspects of the controller 130 may also be designed for portability. For example, the controller 130 may include one or more light sources configured to provide light to one or more optical pressure sensors. To facilitate low-power operation, the light source(s) may be configured as light-emitting diodes (LEDs), which consume substantially less power than conventional tungsten-based light sources. In some embodiments, the controller may include a bus system configured to facilitate power management within the controller and / or the power provided to the heart pump motor.

[0035] In some embodiments, the display 140 may be simplified and / or eliminated as part of the controller 130, further improving the portability of the ventricular assist system. For example, the controller 130 may include a smaller and / or simpler display 140 than those used in conjunction with conventional controllers (e.g., AICs). The smaller / simpler display 140 may be arranged on a portable controller 130 configured to be worn, for example, on a patient's belt / waist. In some embodiments, the controller 130 may be configured without a display 140. Instead, the controller 130 may be configured with a communication component (e.g., configured to implement a short-range communication protocol such as Bluetooth®). The communication component may be configured to wirelessly communicate with an application on a computing device, such as a smartphone, laptop, or tablet computing device. The computing device may be configured to display information using a display on the computing device in response to receiving information from the controller 130. In some embodiments, the computing device may be configured to present a programming interface and allow an authorized user to modify one or more operating parameters of the controller (e.g., pump speed). In this way, it may be possible for a patient or another authorized user to modify the operation of the heart pump (e.g., within boundaries defined by a healthcare professional) without having to travel to a hospital, clinic, or other medical facility and have the ventricular assist device reprogrammed by a healthcare professional. Such programming interfaces may employ security measures to help ensure that the interface cannot be easily hacked by third parties.

[0036] In some embodiments, the portability of the ventricular assist system may be improved by reducing the weight of the controller 130. For example, the maximum weight of the controller 130 may be 3-4 kilograms so that the controller 130 may be worn by the patient. In some embodiments, the weight of the controller 130 may be reduced from the weight of a conventional AIC in several ways, including, but not limited to, having a smaller display or no display, having fewer ports to which external devices can connect, and / or having removable components (e.g., a redundant battery pack).

[0037] As shown, in some embodiments, the ventricular assist system may include a purge subsystem 150 having a container 151, a supply line 152, a purge cassette 153, a purge disk 154, purge tubing 155, a check valve 156, a pressure reservoir 157, an infusion filter 158, and a side arm 159. The container 151 may be, for example, a bag or a bottle. As will be appreciated, in other embodiments, the ventricular assist system may not include a purge subsystem. In some embodiments, a purge fluid may be stored in the container 151. The supply line 152 may provide a fluid connection between the container 151 and the purge cassette 153. The purge cassette 153 may control how the purge fluid in the container 151 is delivered to the heart pump 110. For example, the purge cassette 153 may include one or more valves for controlling the pressure and / or flow rate of the purge fluid. The purge disk 154 may include one or more pressure and / or flow sensors for measuring the pressure and / or flow rate of the purge fluid. As shown, the controller 130 may include a purge cassette 153 and a purge disk 154. Purge tubing 155 may provide a fluid connection between the purge disk 154 and a check valve 156. A pressure reservoir 157 provides additional fill volume between purge fluid exchanges. In some implementations, the pressure reservoir 157 includes a flexible rubber diaphragm that provides additional fill volume using an expansion chamber. An infusion filter 158 helps prevent bacterial contamination and air from entering the catheter tube 117. A side arm 159 provides a fluid connection between the infusion filter 158 and a plug 170.

[0038] Although shown with separate purge tubing and connector cables, it should be understood that in some embodiments, the ventricular assist system may include a single connector with both fluid and electrical lines connectable to the controller 130. In some embodiments, the connector may be designed to facilitate portability and / or modularity of the ventricular assist system. For example, the connector may have one or more universal or standard-compliant ports, configured to allow the heart pump to be used interchangeably with multiple controllers and / or heart pumps. Such versatility of the connector may enable a modular ventricular assist system in which components, such as the controller 130, are more easily replaced with new controllers should the currently connected controllers fail or otherwise become insufficient to maintain proper operation of the heart pumps coupled to them.

[0039] During operation, the controller 130 may be configured to receive measurements from the pressure sensor 114 and the purge disk 154 and control the operation of the motor (not shown) within the motor housing 116 and the purge cassette 153. As described above, the controller 130 may be configured to control and measure the pressure and / or flow rate of the purge fluid through the purge cassette 153 and the purge disk 154. During operation, after exiting the purge subsystem 150 through the side arm 159, the purge fluid may be directed through a purge lumen (not shown) within the catheter tube 117 and the plug 170. The sensor cable (not shown) within the catheter tube 117, the connector cable 160, and the plug 170 may provide an electrical connection between the pressure sensor 114 and the controller 130. The motor cable (not shown) within the catheter tube 117, the connector cable 160, and the plug 170 may provide an electrical connection between the motor within the motor housing 116 and the controller 130. During operation, the controller 130 may be configured to receive measurements from the pressure sensor 114 through a sensor cable (e.g., optical fiber) and control power delivered through a motor cable to the motor within the motor housing 116. By controlling the power delivered to the motor within the motor housing 116, the controller 130 is operable to control the speed of the motor within the motor housing 116.

[0040] Various modifications can be made to ventricular assist system 100 and one or more of its components. For example, one or more additional sensors can be added to heart pump 100. In another example, a signal generator can be added to heart pump 100 to generate a signal indicative of the rotational speed of the motor within motor housing 116. As another example, one or more components of ventricular assist system 100 can be separated. For example, display 140 can be incorporated into a separate device that communicates with controller 130 (e.g., wirelessly or through one or more electrical cables).

[0041] As described herein, a heart pump (e.g., heart pump 110) may include a pressure sensor 114 (e.g., an optical pressure sensor) configured to detect pressure within the aorta of a patient's heart when the heart pump is properly positioned. The pressure signal sensed by pressure sensor 114 may be used, at least in part, to determine the correct positioning of the heart pump within the patient's heart and / or to determine the blood flow rate through the heart pump when in operation. For example, the pressure signal may be used in combination with a motor current signal received from a motor current sensor (not shown) and a set of stored values ​​to determine the flow rate through the heart pump. The differential pressure across the aortic valve may also be determined indirectly based on the pressure signal measuring the pressure within the aorta and the set of stored values.

[0042] In some embodiments, as discussed herein, one or more additional pressure sensors may be incorporated into heart pump 110 to directly sense pressure in both the aorta and the left ventricle, for example, without having to infer pressure in the left ventricle based on a pressure sensor signal sensed in the aorta. The use of multiple pressure sensors is also referred to herein as a multi-channel pressure sensor implementation. FIG. 2 illustrates an embodiment of heart pump 200 in which second pressure sensor 210 is arranged near inlet area 112. When properly positioned within a patient's heart, second pressure sensor 210 may be configured to measure a pressure sensor signal that is used to determine left ventricular blood pressure. In such an implementation, an additional sensor cable (e.g., optical fiber) may be disposed within catheter tube 117 and provide a connection between second pressure sensor 210 and a controller (e.g., controller 130).

[0043] The inventors have recognized and appreciated that accommodating multiple pressure sensors within a heart pump may be useful for providing lower power and / or smaller sensors than pressure sensors used in some conventional heart pumps (e.g., including pressure sensor 114). Additionally, the use of optical-based pressure sensors may have advantages over electronic or other types of pressure sensors, including, but not limited to, their smaller size, their small or negligible pressure drift, and their durability. FIG. 3 schematically illustrates a multi-channel pressure sensor system 300 designed in accordance with some embodiments of the present technology. System 300 includes a light source 310 and multiple optical sensors (e.g., first sensor 340 and second sensor 360) coupled via optical fibers and one or more optical elements. In the exemplary system 300, light source 310 includes two light-emitting diodes (LEDs) (i.e., first LED 312 and second LED 314) configured to output light having different spectra. As described in further detail below, the spectrum of light output from the first LED 312 and the second LED 314 can be selected so that their combined output has some characteristics similar to, for example, white light generated by a tungsten lamp. In some embodiments, the size of the LEDs can be less than one millimeter. Such characteristics can facilitate the use of lower-power LED light sources to implement multi-channel optical pressure sensing in heart pumps in accordance with the techniques described herein. Low-power LED light sources can be particularly beneficial for providing portable ventricular assist systems, where power budgets must be carefully managed to ensure that primary and secondary power sources in the portable system are not suddenly discharged.

[0044] As shown, system 300 includes multiple optical elements arranged between a light source 310 and multiple sensors (e.g., sensors 340, 360). A first optical element 320 is arranged to receive light from a first LED 312 and a second LED 314. In some embodiments, first optical element 320 is implemented as a splitter that mixes the light from the first LED 312 and the second LED 314 and provides the light at its output to a second optical element 330 and a third optical element 350. The light provided as input to second optical element 330 and third optical element 350 may have a composite or “mixed” spectrum from the light output from the first LED 312 and the second LED 314 and may have half the power of the light provided as input to first optical element 320 from light source 310. By mixing light from the first LED 312 and the second LED 314, the first optical element provides light with a spectrum that has some characteristics in common with white light that can be produced using a higher-power (e.g., tungsten-based) light source. It should be understood that other types of light sources and / or optical components may alternatively be used to generate light for use with some embodiments. For example, a single low-power light source 310 configured to generate light with multiple or composite spectra that have some characteristics in common with white light (e.g., light with a broad spectrum) may alternatively be used. In such embodiments, the first optical element 320 configured to mix light from multiple light sources (e.g., LEDs 312 and 314) may not be required, and light output from the single light source may be provided directly to the second optical element 330 and the third optical element 350 via one or more optical fibers.

[0045] In some embodiments, the second optical element 330 may be implemented as a splitter that provides the mixed spectrum light output from the first optical element 320 to the first sensor 340. The first sensor 340 may be configured as a reflective element such that at least a portion of the light provided to the first sensor 340 is reflected back through the second optical element 330, which provides the reflected light as an input to the detector module 370. Similarly, the third optical element 350 may be configured as a splitter that provides the mixed spectrum light output from the first optical element 320 to the second sensor 360. The second sensor 360 may be configured as a reflective element such that at least a portion of the light provided to the second sensor 360 is reflected back through the third optical element 350, which provides the reflected light as an input to the detector module 370. In this manner, the reflected optical signals provided by the first sensor 340 and the second sensor 360 are further processed by components of the detector module 370. In some embodiments, the first optical fiber coupled between the second optical element 330 and the detector module 370 and the second optical fiber coupled between the third optical element 350 and the detector module 370 may be coupled to the detector module 370 via a connector configured to arrange the first optical fiber and the second optical fiber in close proximity to each other.

[0046] As shown, the detector module 370 may include one or more lenses 372 (e.g., plano lenses, aspheric lenses, biconvex lenses, etc.), a Fizeau interferometer 374, and an image sensor 376. In some embodiments, the lenses 372 may be implemented as a pair of D-shaped lenses facing each other, as described in further detail herein. The lenses 372 may be used to reduce spherical aberration, thereby allowing multiple channels of light reflected from the sensor to be separated in space and represented on the detector as two (or more) parallel or nearly parallel lines with limited crosstalk between them. Light received by the lenses 372 is provided as an input to the Fizeau interferometer 374. The Fizeau interferometer 374 may be implemented as two reflective mirrors with a spatially varying dielectric layer arranged between them. Light entering the Fizeau interferometer 374 may resonate at a specific location on the spatially varying dielectric layer, generating a beam of light that is captured by the detector 376, for example, as shown in FIG. 7A. In some embodiments, image sensor 376 may be configured as a two-dimensional image sensor in which multiple channels of light corresponding to interference fringes in the reflected light signals from first sensor 340 and second sensor 360 are detected. System 300 may further include at least one hardware processor 380 configured to analyze the signals captured by image sensor 376 and, for example, determine the pressure sensed by each of first sensor 340 and second sensor 360 based on the interference fringe signals captured by image sensor 376. In some embodiments, at least one hardware processor 380 may be implemented as part of controller 130, as described above with respect to FIG. 1C .

[0047] FIG. 4 schematically illustrates the arrangement of components of a detector module 370, according to some embodiments. As shown, the detector module 370 includes a connector 410 configured to receive optical fibers from the second optical element 330 and the third optical element 350, as described above with respect to FIG. 3. The connector 410 may be configured to arrange the incoming optical fibers in close proximity to one another. Two beams of light output from the connector 410 are provided to a lens 372, which focuses the light onto a Fizeau interferometer 374, which redirects the light onto the surface of an image sensor 376. In some embodiments, the connector 410 is movable in a plane parallel to the lens 372 to adjust the focusing of the light beams on the image sensor 376. As shown, the lens 372 may be implemented as a set of D-shaped lenses with their curved edges oriented toward one another. The lens 372 may be configured to reduce spherical aberration that would be present, for example, if rod lenses were used.

[0048] FIG. 5 schematically illustrates a process for performing interferometric measurements using an optical system such as those described herein. In the example of FIG. 5, a white light source (e.g., a tungsten lamp) is used as the light source (e.g., light source 310 in FIG. 3). However, it should be understood that other light sources (e.g., LEDs 312, 314) may alternatively be used. As shown, light generated by the source is provided via an optical fiber to a sensor (e.g., sensor 340 or sensor 360 in FIG. 3) as incident light I0. As shown, the sensor may be implemented as a transducer-sensing interferometer. The reflected light I r is provided to a detector module (e.g., detector module 370) that includes a tuning wedge (e.g., Fizeau interferometer 374) that is used to produce an interference fringe signal (e.g., on an image sensor 376). The central peak of the interference fringe signal can be tracked and / or otherwise used to determine the pressure value sensed by the sensor.

[0049] As discussed herein, the inventors recognize and understand that some conventional white light sources generate significant amounts of heat and use large amounts of power, which, in certain implementations, limits their use, including as a light source for a multi-channel optical pressure sensor in a portable ventricular assist system. Accordingly, in some embodiments, one or more lower power light sources may be used to provide light having some characteristics similar to white light. For example, as described above in connection with the system 300 shown in FIG. 3, two LED sources configured to generate light having different spectra may be used.

[0050] Figure 6A shows a plot of the spectrum of light output by a white light source (top plot) and the corresponding interference fringe signal recorded using the white light source (bottom plot). As shown, a conventional white light source has a broadband spectrum, which produces an interference fringe signal with a well-defined central region, along with small side lobes. Such an interference fringe signal is ideal for determining pressure sensed by a combined optical pressure sensor. Figure 6B shows a plot of the spectrum of light output by two narrowband LED sources (top plot) and the corresponding interference fringe signal recorded using the two LED sources (bottom plot). The spectrum of light produced by the first LED source may have a lower peak wavelength (e.g., in the range of 550-650 nm), while the spectrum of light produced by the second LED source may have a higher peak wavelength (e.g., in the range of 800-900 nm). In some embodiments, the spectrum of light produced by the first LED source has a peak wavelength in the range of 550-610 nm, and the spectrum of light produced by the second LED source has a peak wavelength in the range of 820-850 nm, and in some embodiments, the peak wavelength of the first LED source is 4 / 5 of the peak wavelength of the second LED source.

[0051] As shown in the bottom plot of FIG. 6B , the interference fringe signal produced using two narrowband LED sources has some characteristics similar to the interference fringe signal produced using a broadband white light source shown in FIG. 6A . For example, the interference fringe signal shown in FIG. 6B has a central portion similar to that of the interference fringe signal shown in FIG. 6A and lateral envelopes that distinguish the central region from other portions of the signal. When the lateral envelopes adjacent to the central portion of the signal drop sufficiently to allow tracking of the central portion of the signal relative to other portions of the signal, the interference fringe signal shown in FIG. 6B can be used in a manner similar to the interference fringe signal shown in FIG. 6A and as described above in connection with the process shown in FIG. 5 . Thus, some embodiments mimic the use of a broadband white light source by using multiple narrowband and lower power LED sources, which, when used in combination, generate an interference fringe signal that can be used in a multi-channel optical pressure sensor (e.g., for a heart pump). In some embodiments, one or more characteristics (e.g., amplitude, position) of the central peak of the central portion of the interference fringe signal can be used to determine the pressure value sensed by the corresponding pressure sensor associated with the interference fringe signal. In some embodiments, more than two light sources (e.g., LEDs) can be used, and it should be understood that the embodiments are not limited in this respect. Thus, although a two-channel optical pressure sensor system is shown and described herein, any multi-channel (e.g., two or more channels) optical pressure sensor system can be implemented using techniques similar to those described herein. In embodiments where more than two channels are used, more than two light sources can be beneficial so that the power of the optical signal provided to each of the sensors is sufficient to generate a reliable interference fringe signal.

[0052] FIG. 7A illustrates a display of an image representing interference fringe signals captured by a two-dimensional image sensor (e.g., image sensor 376 shown in FIG. 3 ), according to some embodiments. As shown, the interference fringe signals captured by the image sensor for each of the corresponding optical sensors are represented as lines. For example, a first interference fringe signal corresponding to light reflected from sensor 340 may be represented as line 710, and a second interference fringe signal corresponding to light reflected from sensor 360 may be represented as line 720. As described herein, components of the detector module may enable the interference fringe signals represented as lines 710 and 720 to be spatially distinguishable and separable (e.g., with no or limited crosstalk). While only a small portion of the image sensor shown in FIG. 7A is shown utilized, it should be understood that this demonstrates the feasibility of using more than two channels, as desired, in accordance with the techniques described herein. For example, in some embodiments, up to six, eight, or ten channels may be used. The intensity of the interference fringe signal can be extracted from the captured image sensor signal into an interference fringe signal such as that shown in Figure 7B. Based at least in part on the extracted interference fringe signal, the pressure sensed by the corresponding sensor can be determined, as described above.

[0053] 8 schematically illustrates a portable ventricular assist system 800, according to some embodiments. The portable ventricular assist system 800 may include a heart pump 810 and hardware controller(s) 820 coupled to the heart pump 810 via a connector 830. As described herein, the connector 830 may be configured to include one or more optical connections (e.g., multiple optical connections having different parameters) and one or more electrical connections configured to transmit optical and electrical signals, respectively, between the hardware controller(s) 820 and the heart pump 810 during operation. Although shown as only a single connector 830, it should be understood that in some embodiments, multiple connectors 830 may be used to couple to the heart pump 810 and the hardware controller(s) 820.

[0054] 8, heart pump 810 may include a rotor 812 and a motor 814 configured to drive rotation of rotor 812 according to one or more operating parameters received from hardware controller(s) 820 via connector 830. Heart pump 810 may further include a first optical pressure sensor 816 configured to sense a first pressure signal within the patient's aorta, for example, and a second optical pressure sensor 818 configured to sense a second pressure signal within the patient's left ventricle.

[0055] The hardware controller(s) 820 may include, at least in part, LED(s) 822 configured to provide light to the first optical pressure sensor 816 and the second optical pressure sensor 818 via one or more optical fibers arranged in a connector 830. The hardware controller(s) 820 may further include hardware processor(s) 824 coupled to the heart pump 810 via the connector 830. The hardware processor(s) 824 may be configured to control one or more operations (e.g., pump speed) of the heart pump 810 during operation and to receive information regarding one or more operating parameters of the heart pump 810. Examples of such information regarding the one or more operating parameters are described herein. The hardware controller(s) 820 may further include a primary power source 826 and a secondary power source 828 configured to provide power to components (e.g., the motor 814) of the heart pump 810 via a switch 840 and the connector 830. As will be appreciated, although shown as having two power sources, in some embodiments, the hardware controller may include only a single (e.g., primary) power source. As described herein, power provided to the heart pump 810 by the hardware controller(s) 820 may be switched from the primary power source 826 to the secondary power source 828 (or vice versa) as needed to ensure sustained and safe operation of the heart pump 810. In some embodiments, the switching from the primary power source 826 to the secondary power source 828 (or vice versa) may be performed in response to a signal from the hardware processor(s) 824, which may be configured to monitor the charge levels of the primary power source 826 and the secondary power source 828. In some embodiments, the hardware controller(s) 820 may further include communication circuitry 850 configured to provide information to a computing device (e.g., a smartphone, laptop computer, tablet computer) for display.In some embodiments, the communications circuitry 850 may be configured, at least in part, as a programming interface to allow programming of the cardiac pump operating parameters set by the hardware processor(s) 824.

[0056] Having thus described several aspects and embodiments of the technology described in this disclosure, it should be understood that various alternatives, modifications, and improvements will readily occur to those skilled in the art. Such alternatives, modifications, and improvements are intended to be within the spirit and scope of the technology described herein. For example, those skilled in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or obtaining one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the embodiments described herein. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It should therefore be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and their equivalents, embodiments of the invention may be practiced otherwise than as specifically described. Additionally, any combination of two or more features, systems, articles, materials, kits, and / or methods described herein is included within the scope of the present disclosure, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

[0057] The embodiments described above can be implemented in any of numerous ways. One or more aspects and embodiments of the present disclosure involving the implementation of a process or method may utilize program instructions executable by a device (e.g., a computer, processor, or other device) to perform the process or method or to control the implementation of the process or method. In this regard, various inventive concepts may be embodied as a computer-readable storage medium (or multiple computer-readable storage media) (e.g., computer memory, one or more floppy disks, compact disks, optical disks, magnetic tapes, flash memory, circuitry within a field programmable gate array or other semiconductor device, or other tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement one or more of the various embodiments described above. The computer-readable medium(s) may be transportable such that the program(s) stored thereon can be loaded onto one or more different computers or other processors to implement various of the aspects described above. In some embodiments, the computer-readable medium may be non-transitory.

[0058] The above-described embodiments of the present technology can be implemented in any of numerous ways. For example, the embodiments can be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers. It should be understood that any component or collection of components that performs the functions described above can generally be considered a controller that controls the functions described above. The controller can be implemented in numerous ways, such as using dedicated hardware or general-purpose hardware (e.g., one or more processors) programmed with microcode or software to perform the functions listed above, and when the controller corresponds to multiple components of a system, it can be implemented in a combination of ways.

[0059] Further, it should be understood that the computer may be embodied in any of several forms, such as, by way of non-limiting examples, a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer. In addition, the computer may be embedded within a device that is not generally considered a computer but has suitable processing capabilities, including a personal digital assistant (PDA), a smartphone, or any other suitable portable or fixed electronic device.

[0060] A computer may also have one or more input and output devices. These devices may be used, among other things, to present a user interface. Examples of output devices that may be used to provide a user interface include a printer or display screen for visual presentation of output and a speaker or other sound generating device for audible presentation of output. Examples of input devices that may be used for a user interface include keyboards and pointing devices such as mice, touchpads, and digitizing tablets. As another example, a computer may receive input information through speech recognition or in other audible formats.

[0061] Such computers may be interconnected by one or more networks in any suitable form, including local or wide area networks such as enterprise networks, and intelligent networks (IN) or the Internet. Such networks may be based on any suitable technology and operate according to any suitable protocol, and may include wireless networks, wired networks, or fiber optic networks.

[0062] Also, as described, some aspects may be embodied as one or more methods. Acts performed as part of a method may be ordered in any suitable manner. Thus, embodiments may be constructed in which acts are performed in an order different from that illustrated, which may include performing some acts simultaneously even though shown as sequential acts in the illustrative embodiments.

[0063] All definitions, as defined and used herein, should be understood to supersede dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0064] The indefinite articles "a" and "an," as used in the specification and claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0065] The term "and / or," as used in the specification and claims, should be understood to mean "one or both" of the elements so conjoined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" should be construed in the same manner, i.e., as "one or more" of the elements so conjoined. Other elements, whether related or unrelated to those elements specifically identified, may optionally be present other than the elements specifically identified by the "and / or" clause. Thus, as a non-limiting example, a reference to "A and / or B," when used in conjunction with open-ended language such as "comprising," can refer in one embodiment to A only (optionally including elements other than B); in another embodiment to B only (optionally including elements other than A); in yet another embodiment to both A and B (optionally including other elements), etc.

[0066] As used in the specification and claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but does not necessarily include at least one of every element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to those specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently, "at least one of A and / or B") can refer in one embodiment to at least one (optionally, including more than one) A in the absence of B (optionally, including elements other than B); in another embodiment to at least one (optionally, including more than one) B in the absence of A (optionally, including elements other than A); in yet another embodiment to at least one (optionally, including more than one) A, at least one (optionally, including more than one) B (optionally, including other elements), etc.

[0067] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use herein of "including," "comprising," "having," "containing," "involving," and variations thereof, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0068] In the claims and the above specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like, are intended to be open-ended, i.e., understood to mean "including but not limited to." Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively.

[0069] The use of ordinal numbers such as "first," "second," "third," etc. in the claims to modify claim elements does not, by itself, imply any priority, precedence, or order of one claim element relative to another, or the chronological order in which acts of a method are performed, but merely distinguishes one claim element having a certain name from another element having the same name (absent the use of ordinal terms) and is used as a label to distinguish the claim elements.

Claims

1. 1. A portable ventricular assist system, comprising: A heart pump, the heart pump comprising: A rotor, a motor configured to drive rotation of the rotor at one or more speeds; a first optical pressure sensor configured to detect a first pressure signal; a second optical pressure sensor configured to detect a second pressure signal; and a heart pump comprising: at least one hardware controller, said at least one hardware controller comprising: A primary power source; A secondary power source; at least one light emitting diode (LED), the at least one LED coupled to the first optical pressure sensor via at least one first optical fiber and coupled to the second optical pressure sensor via at least one second optical fiber; at least one hardware processor configured to determine a differential pressure based at least in part on the first pressure signal and the second pressure signal; At least one hardware controller comprising:

1. A portable ventricular assist system comprising:

2. and a connector configured to connect the heart pump and the at least one hardware controller, the connector comprising: at least one electrical connection for connecting the primary power source and / or the secondary power source to the motor; at least one optical connection for connecting the at least one LED to the first optical pressure sensor and the second optical pressure sensor; 10. The portable ventricular assist system of claim 1, comprising:

3. 10. The portable ventricular assist system of claim 1, wherein the at least one hardware controller further comprises a bus system configured to manage power supplied to the motor by the primary power source and / or the secondary power source.

4. 4. The portable ventricular assist system of claim 3, wherein the bus system is configured to automatically switch power provided from the primary power source to the secondary power source when a state of charge is below a threshold amount.

5. 10. The portable ventricular assist system of claim 1, further comprising at least one indicator LED configured to indicate a current state of charge of the primary power source and / or the secondary power source.

6. 10. The portable ventricular assist system of claim 1, further comprising communications circuitry configured to provide information to a computing device for display, the information including one or more quantities associated with operation of the cardiac pump.

7. The portable ventricular assist system of claim 6 , wherein the one or more quantities include a motor current amount associated with operation of the heart pump.

8. The portable ventricular assist system of claim 6 , wherein the one or more quantities include one or more physiological quantities associated with a patient while the heart pump is in operation.

9. 9. The portable ventricular assist system of claim 8, wherein the one or more physiological quantities include a differential pressure measurement across the patient's aortic valve.

10. The portable ventricular assist system of claim 6 , wherein the communication circuitry is configured to provide the information to the computing device wirelessly.

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