Determining cardiac parameters to adjust blood pump support

Abstract

To provide systems, devices, and methods for providing cardiac support to a heart.SOLUTION: The systems, devices, and methods use a blood pump to obtain measurements of cardiac functions. The systems quantify the functions of the native heart by measuring certain parameters / signals such as aortic pressure or motor current, then calculate and display one or more cardiac parameters and cardiac function parameters, such as left ventricular pressure, left ventricular end diastolic pressure or cardiac power output.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 62 / 517,668, “Determination of Cardiac Parameters for Modulation of Blood Pump Support,” filed Jun. 9, 2017, and U.S. Provisional Patent Application No. 62 / 635,662, “Determination of Cardiac Parameters for Modulation of Blood Pump Support,” filed Feb. 27, 2018, each of which is hereby incorporated by reference in its entirety.

Background Art

[0002] background Intravascular blood pumps provide hemodynamic support and promote cardiac recovery. Intravascular blood pumps are inserted into the heart to provide supplemental cardiac support to patients with cardiovascular disease and to supplement cardiac output in parallel with the native heart. One example of such a device is the IMPELLA® device family (Abiomed, Inc., Danvers MA).

[0003] Currently, it is difficult for clinicians to directly and quantitatively determine the amount of support a device should deliver or when to discontinue the use of cardiac assist devices. Therefore, clinicians tend to rely on qualitative judgments and indirect estimates of cardiac function, such as measuring intracardiac or intravascular pressure using fluid-filled catheters. Traditionally, left ventricular pressure (LVP) has been estimated by measuring pulmonary artery wedge pressure (PAWP) or pulmonary capillary wedge pressure (PCWP), which is performed by inserting a balloon-containing pulmonary catheter into a branch of the pulmonary artery. Because pulmonary artery catheterization is intermittent, indirect, and inconsistent, PAWP and PCWP are not reliable measures of cardiac health, as they yield inaccurate data that clinicians cannot trust to make clinical decisions regarding the level of cardiac support a patient needs.

[0004] A blood pump provides supplemental cardiac support by assisting in the pumping of blood through the heart's chambers, such as from the left ventricle or left atrium into the aorta, and from the right ventricle or right atrium into the pulmonary artery. A blood pump is typically inserted to provide supplemental cardiac support for a period of time, after which the patient is weaned off the pump so that the heart can pump blood independently. Because clinicians often lack access to reliable information about cardiac function, patients are frequently weaned too early and too quickly, placing an unnecessary burden on the heart.

[0005] If left ventricular pressure, cardiac power output, and other cardiac variables are accurately measured, clinicians may be able to make better clinical decisions for patients based on their current cardiac needs. Therefore, there is a long-term need for improvements to the current system in informing clinicians about cardiac support and cardiac health. [Overview of the project]

[0006] overview In some embodiments, a method for providing cardiac assistance to the heart includes the steps of operating a blood pump positioned within the heart, the blood pump comprising a cannula and a motor that operates at a certain motor speed and draws a variable current to provide a certain level of cardiac assistance to the heart. The blood pump also includes a controller connected to the blood pump. The method also includes the steps of the controller measuring aortic pressure; measuring motor current and motor speed; determining a pressure gradient across the cannula associated with the motor current and motor speed; and using a processor to calculate cardiac parameters, such as left ventricular pressure (LVP) or left ventricular end-diastolic pressure (LVEDP), derived from the aortic pressure and the pressure gradient across the cannula associated with the motor current and motor speed. The method also includes the steps of recording the calculated cardiac parameters in memory; and determining cardiac function parameters, such as a measure of cardiac output, using the calculated cardiac parameters. The method subsequently performs the steps of determining recommended changes to the assistance provided by the blood pump based on the calculated cardiac parameters and cardiac function parameters; and generating the recommended changes to the assistance for display. Recommended changes to the support may include, for example, recommendations to increase or decrease the motor speed during weaning; recommendations to adjust the placement of the blood pump in response to aspiration events; or recommendations to switch to a different blood pump with different capabilities, and other recommendations may also be present. The method may also include a step of generating calculated cardiac parameters and cardiac function parameters for display. Displaying important cardiac parameters and cardiac function parameters enables healthcare professionals to make informed decisions about adjusting blood pump support for the patient. Furthermore, by calculating these parameters based on the blood pump motor current and motor speed and the measured aortic pressure, it becomes possible to determine recommendations for adjusting and adjusting the blood pump, and these recommendations may be provided to healthcare professionals to help determine potential problems and facilitate adjustments to care. [Invention 1001] Methods for providing cardiac support to the heart, including the following steps: A step of operating a blood pump located within the heart, wherein the blood pump has a cannula and includes a motor that operates at a certain motor speed and draws a variable motor current to provide a certain level of cardiac support to the heart; A step in which the aortic pressure is measured in a controller connected to the blood pump; A step in which the controller measures the motor current and the motor speed; A step of determining the pressure gradient across the cannula, associated with the motor current and the motor speed; A step of using a processor to calculate cardiac parameters derived from the aortic pressure and the pressure gradient across the cannula, associated with the motor current and motor speed; The step of recording the calculated cardiac parameters in memory; A step in which cardiac function parameters are determined based on the calculated cardiac parameters; A step of determining a recommended change to the level of cardiac support provided by the blood pump, based on the calculated cardiac parameters and at least one of the cardiac function parameters; The stage of generating the recommended changes for display. [Invention 1002] A stage in which user input is accepted in response to a displayed recommended change in the level of cardiac support provided by the blood pump; and A step in adjusting the motor speed to adjust the level of cardiac support according to the user input. The method of the present invention 1001, further comprising: [Invention 1003] The method of the present invention 1002, wherein the step of adjusting the motor speed according to user input includes a step of increasing the motor speed in order to increase blood flow from the heart. [Invention 1004] The method of the present invention 1002, wherein the step of adjusting the motor speed according to user input includes a step of reducing the motor speed in order to disengage the heart from cardiac support. [Invention 1005] A method according to any one of the present invention 1001 to 1004, wherein the calculated cardiac parameter is at least one of left ventricular pressure, left ventricular end-diastolic pressure, aortic pulse pressure, and mean aortic pressure. [Invention 1006] A method according to any one of items 1001 to 1005 of the present invention, wherein the cardiac function parameter is selected from cardiac output and cardiac power output. [Invention 1007] Any method of the present invention 1001 to 1006 further includes the step of accessing a history of previously recorded cardiac parameters and cardiac function parameters in memory. [Invention 1008] Any method of the present invention 1001 to 1007, further comprising the step of generating at least one of the calculated cardiac parameters and cardiac function parameters as a function of time for display. [Invention 1009] The method of the present invention 1007, wherein the determined recommended change to motor speed is based on a history of at least one of previously recorded cardiac parameters and cardiac function parameters. [Invention 1010] The stage in determining recommended changes in support is, A step in determining changes in one of the calculated cardiac parameters or cardiac function parameters based on a history of previously recorded cardiac parameters and cardiac function parameters; Based on the change, the step of determining the recommended modifications in the level of cardiac support provided; and The step of converting the recommended modifications in the provided cardiac support level to the recommended changes in motor speed. Any method of the present invention 1001 to 1009, further comprising the above. [Invention 1011] Determining a suction event at an inlet of the blood pump based on at least one of the calculated cardiac parameters and cardiac function parameters; and Generating a warning of the suction event for display The method according to any one of inventions 1001 to 1010, further comprising. [Invention 1012] Identifying a cause of the suction event based on at least one of the calculated cardiac parameters and cardiac function parameters; and Generating a recommendation for addressing the cause of the suction event for display The method of invention 1011, further comprising. [Invention 1013] The step of identifying the cause of the suction event is Comparing the value of the calculated cardiac parameter with a threshold value, wherein the cardiac parameter is the left ventricular pressure and the threshold value is zero; and Comparing the value of the left ventricular pressure over the cardiac cycle with the value of the aortic pressure over the cardiac cycle The method of invention 1012, comprising. [Invention 1014] Identifying a diastolic suction event if the minimum value of the left ventricular pressure is less than the threshold value during diastole of the cardiac cycle but normal during systole The method of invention 1013, further comprising. [Invention 1015] Identifying a systolic suction event if the minimum value of the left ventricular pressure is less than the threshold value during diastole and the value of the left ventricular pressure does not exceed the value of the aortic pressure over the cardiac cycle [[ID=XXX]] The method of invention 1013, further comprising. [Invention 1016] A blood pump configured to be disposed within the heart, A cannula, A sensor configured to measure aortic pressure within the heart, and A motor configured to operate at a certain motor speed and draw a variable motor current to provide a certain level of cardiac support to the heart Comprising a blood pump; A controller configured to control the motor current and motor speed, a memory, a user interface, and a processor, which measures the motor current and motor speed of the motor, receives the index of the aortic pressure from the sensor, converts the index of the aortic pressure into an aortic pressure measurement value, determines a pressure gradient across the cannula associated with the motor current and the motor speed, calculates at least one cardiac parameter based on the aortic pressure measurement value and the pressure gradient across the cannula, records the at least one calculated cardiac parameter in the memory, calculates one or more cardiac function parameters based on the at least one cardiac parameter, determines a recommended change to the level of cardiac support based on at least one of the at least one cardiac parameter and the one or more cardiac function parameters, generates the recommended change to the level of cardiac support for display on the user interface is configured as such, a processor A controller comprising A percutaneous blood pump system comprising. [Invention 1017] The blood pump system of Invention 1016, wherein the processor is further configured to calculate the left ventricular end-diastolic pressure as a cardiac parameter and the cardiac output as a cardiac function parameter [Invention 1018] The processor records at least one calculated cardiac parameter in the memory as a calculated first cardiac parameter, and at a later time, records a calculated second cardiac parameter in the memory A blood pump system according to any of the present invention 1016 to 1017, further comprising the above configuration. [Invention 1019] The processor, Access the primary and secondary cardiac parameters in memory, Based on the comparison value of the first cardiac parameter to the second cardiac parameter, the recommended changes to the motor speed are determined. A blood pump system according to any of the invention 1016 to 1018, further comprising the above configuration. [Invention 1020] The processor, Based on at least one of the calculated cardiac parameters and cardiac function parameters, the suction event at the blood pump inlet is determined. Generate a warning for aspiration events for display on the user interface. A blood pump system according to any of the invention 1016 to 1019, further comprising the above configuration. [Brief explanation of the drawing]

[0007] The above and other purposes and advantages will become clear upon consideration of the following detailed description in conjunction with the attached drawings. Throughout the attached drawings, similar reference numerals refer to similar parts.

[0008] [Figure 1] This diagram shows the intravascular cardiac pump system located within the heart. [Figure 2-1] Figure 2A is an illustrative plot of the pressure gradient against motor current. Figure 2B is an illustrative plot showing the measured aortic pressure and calculated LVP as a function of time. [Figure 2-2] Figure 2C is an illustrative plot showing the LVP waveform and aortic pressure waveform as functions of time. Figure 2D is an illustrative plot showing the first time derivative of the LVP waveform as a function of time. Figure 2E is an illustrative plot showing the second time derivative of the LVP waveform as a function of time. [Figure 3]This diagram shows an exemplary user interface for a cardiac pump controller, displaying measurements over time. [Figure 4] This diagram illustrates the process for optimizing the performance of the blood pump within the heart based on measured and calculated cardiac parameters. [Figure 5A] This diagram illustrates intermittent suction events in a blood pump and shows an exemplary user interface for a cardiac pump controller. [Figure 5B] This diagram illustrates a continuous suction event in a blood pump and shows an exemplary user interface for a cardiac pump controller. [Figure 5C] This diagram illustrates an exemplary user interface for a cardiac pump controller, showing a screen illustrating the trend of measured values. [Figure 5D] This diagram illustrates an exemplary user interface for a cardiac pump controller, showing changes in cardiac function during withdrawal as captured by the displayed measured values. [Figure 6] This diagram illustrates the process for determining heart rate output and displaying recommendations to the user regarding adjustments to pump assistance. [Figure 7] This diagram illustrates the process for recommending adjustments to motor speed based on measured and calculated cardiac parameters. [Figure 8] This diagram illustrates the process for recommending adjustments to motor speed based on heart rate output and LVEDP. [Figure 9] This diagram illustrates the process for recommending a higher-flow treatment device based on measured and calculated cardiac parameters. [Figure 10] This diagram illustrates the process for recommending drug therapy based on measured and calculated cardiac parameters. [Figure 11] This diagram illustrates the process for alerting users to predicted cardiac adverse events based on measured and calculated cardiac parameters. [Figure 12] This diagram illustrates the process for balancing the right and left ventricular blood pump devices during biventricular support, based on measured and calculated cardiac parameters. [Figure 13] This diagram illustrates the process for automatically adjusting the level of support provided by the blood pump. [Figure 14] This is a block diagram of an exemplary blood pump system. [Modes for carrying out the invention]

[0009] Detailed explanation Specific exemplary embodiments are described so that the systems, methods, and devices described herein may be understood in their entirety. While the embodiments and features described herein specifically relate to use in relation to percutaneous blood pump systems, it should be understood that all components and other features outlined below may be combined with each other in any preferred manner and may be adapted and applied to other types of cardiac treatments and cardiac support devices, including cardiac support devices implanted using surgical incisions.

[0010] The systems, devices, and methods described herein provide mechanisms for providing clinical professionals with cardiac parameters and cardiac function parameters based on motor current, motor speed, and aortic pressure measured in a blood pump system. The functionality and output of the intravascular blood pump may be used in conjunction with measurable cardiac parameters to calculate additional parameters useful in determining the patient's cardiac function and health status. Making these decisions and presenting the data to clinical professionals in a useful and meaningful way increases the amount of data available to them to inform medical decision-making. Additional cardiac parameters and cardiac functions, as well as their trends, accessible by algorithms based on intravascular blood pump output, enable clinical professionals to make informed decisions regarding cardiac support provided to patients through various blood pumps, blood pump placement, and therapeutic drug administration. The algorithm also enables the blood pump system to determine key cardiac parameters and display them to clinical professionals to inform patient care decision-making; or to provide recommendations for adjusting support, for example, by displaying recommendations to clinical professionals to vary the level of cardiac function based on inputs of various cardiac parameters.

[0011] Calculating various cardiac parameters from the function of the blood pump is possible based on knowledge about the operation of the blood pump, such as insights into the cardiac pressure and flow responses in relation to the blood pump's operating speed and input power. Based on the operational functionality of the pump within the heart, algorithms can be constructed to calculate how cardiac metric values ​​fluctuate as the blood pump interacts with the cardiac system. By making these decisions and providing clinical professionals with immediate and chronological cardiac parameters, they can better understand and respond to changes in the functionality of the blood pump or the patient's cardiac health.

[0012] Specifically, providing clinicians with accurate and timely cardiac parameters such as LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, heart rate, cardiac output, cardiac output, spontaneous cardiac output, spontaneous cardiac output, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac unloading index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance enables clinicians to make informed decisions about patient care. Both total cardiac output and spontaneous cardiac output can be determined using the methods and systems described herein. In this specification, spontaneous cardiac output is used to describe cardiac output from the heart alone, without the contribution of the blood pump. Similarly, spontaneous cardiac output is used to describe the cardiac output of the heart without any contribution from the blood pump. In contrast, total cardiac output is used herein to describe the cardiac output resulting from the combination of the heart and the blood pump. Similarly, total cardiac output is used to describe the cardiac output of the heart, including both the contribution of the cardiac spontaneous output and the blood pump. Throughout this application, when cardiac output or cardiac output is determined or calculated, the systems and methods described herein can calculate either total cardiac output or spontaneous cardiac output, and references to cardiac output or cardiac output may refer to either spontaneous output or total output.

[0013] The algorithms discussed herein enable clinical professionals to make informed decisions about patient weaning. Clinical professionals can better determine the appropriate timing for weaning a patient from cardiac support provided by a blood pump, based on the parameters provided. Furthermore, the algorithms provided herein may enable clinical professionals to make decisions about a reasonable pace for patient weaning by providing recommendations on the level of support, motor speed, and appropriate blood pumps to provide recommended motor speeds for supporting cardiac function.

[0014] The systems, devices, and methods described herein further assist in optimizing blood pump performance by measuring and calculating cardiac parameters. In conjunction with other cardiac metrics, LVP estimation and real-time display of LVP waveforms enable physicians to understand the patient's current and historical cardiac function, as well as the level of support provided by the blood pump. Physicians use this information to make decisions regarding modifications to the level of support provided (e.g., weaning the patient from support or increasing the support provided); blood pump placement and functionality; and the occurrence of aspiration events; as well as other clinical decisions described below.

[0015] The systems, devices, and methods described herein enable clinical healthcare professionals to visually determine whether a blood pump is properly positioned and functioning within the heart. LVP estimation is highly sensitive to aspiration events and can be used to inform clinical healthcare professionals about aspiration events and improper positioning, as well as to assist in repositioning the pump within the heart. Cardiac quantification values, determined according to the algorithms described herein and displayed to clinical healthcare professionals, can further assist in identifying the cause of aspiration events when they occur.

[0016] In addition, the systems, devices, and methods described herein provide clinicians with data and recommendations to provide additional therapeutic support, such as administering drug therapy to patients to help restore cardiac function. For example, an algorithm can provide recommendations on whether drug therapy may be beneficial based on cardiac parameters and their trends, and can also provide dosage information. Trends in cardiac parameters such as spontaneous cardiac output, end-diastolic pressure, and cardiac output may be provided to clinicians, and the algorithm may make recommendations based on these trends to assist in determining the dosage of inotropic agents.

[0017] Alternatively, cardiac parameters to assist in regulating fluid administration and the patient's volume state may be presented to the clinical professional. Variations in spontaneous output, end-diastolic pressure, and pulse pressure may be provided to the clinical professional to enable them to determine whether the patient is within the optimal fluid window and to assess the patient's fluid responsiveness. Based on these parameters, the algorithm may provide the clinical professional with notifications indicating whether the patient is considered to be within the optimal fluid window and indicators of the patient's likelihood of responding to fluid administration.

[0018] The systems, devices, and methods described herein may be used to provide warnings to clinicians regarding predicted adverse events based on measured and calculated cardiac parameters. Patients relying on blood pump assistance are at risk of further ischemic events. Small changes in left ventricular contractility, left ventricular flaccidity, and LVEDP are all early indicators of asymptomatic ischemic events. Highlighting changes in these parameters to clinicians enables them to detect ischemic events earlier and respond more quickly. In addition, other adverse events and outcomes include aortic regurgitation and conduction abnormalities requiring a pacemaker (in patients undergoing balloon aortic valve repair (BAV) in preparation for transcatheter aortic valve replacement (TAVR)). Changes in left ventricular flaccidity, left ventricular diastolic filling pressure, systolic pressure gradient, cardiac output, and total heart rate output can all serve as early indicators of such events and may be calculated and detected by the algorithms described herein and presented to clinicians.

[0019] Furthermore, the systems, devices, and methods described herein may be used, for example, to balance a right-ventricular device and a left-ventricular device used simultaneously to provide biventricular support; balancing the two devices may present unique challenges in maintaining appropriate pressure in the lungs and limiting the risk of pulmonary edema. The algorithm may provide clinicians with information on parameters such as spontaneous output and total output, measured in conjunction with pulmonary artery pressure and left ventricular diastolic pressure, to inform decision-making regarding the operation of the biventricular devices, and may also provide recommendations to help clinicians balance the two devices.

[0020] The systems, devices, and methods presented herein describe mechanisms for measuring various cardiac and cardiac function parameters within a blood pump system, based on blood pump output and measured pressure signals, which are useful for clinical healthcare professionals in the care and treatment of patients being treated with blood pump-assisted cardiac support. The parameters and recommendations provided by the algorithms may be used by clinical healthcare professionals to inform various decision-making processes for medical treatment, as described below.

[0021] Figure 1 shows an exemplary prior art cardiac assist device located within the heart 102. The heart 102 includes the left ventricle 103, the aorta 104, and the aortic valve 105. The intravascular cardiac pump system includes a catheter 106, a motor 108, a pump outlet 110, a cannula 111, a pump inlet 114, and a pressure sensor 112. The motor 108 is connected to the catheter 106 at its proximal end and to the cannula 111 at its distal end. The motor 108 also drives a rotor (not shown in the figure) which rotates to pump blood from the pump inlet 114 through the cannula 111 to the pump outlet 110. The cannula 111 is positioned across the aortic valve 105 such that the pump inlet 114 is located within the left ventricle 103 and the pump outlet 110 is located within the aorta 104. This configuration allows the intravascular cardiac pump system 100 to pump blood from the left ventricle 103 into the aorta 104 to assist cardiac output.

[0022] The intravascular cardiac pump system 100 pumps blood from the left ventricle into the aorta in parallel with the spontaneous cardiac output of the heart 102. Blood flow through a healthy heart is typically about 5 liters / min, and blood flow through the intravascular cardiac pump system 100 may be a similar or different flow rate. For example, the flow rate through the intravascular cardiac pump system 100 may be 0.5 liters / min, 1 liter / min, 1.5 liters / min, 2 liters / min, 2.5 liters / min, 3 liters / min, 3.5 liters / min, 4 liters / min, 4.5 liters / min, 5 liters / min, greater than 5 liters / min, or any other preferred flow rate.

[0023] The motor 108 of the intravascular cardiac pump system 100 may vary in any number of respects. For example, the motor 108 may be an electric motor. The motor 108 may operate at a constant rotational speed to pump blood from the left ventricle 103 to the aorta 104. Since the load on the motor 108 fluctuates at different stages of the cardiac cycle of the heart 102, it is generally necessary to supply a fluctuating amount of current to the motor 108 in order to operate it at a constant speed. For example, when the mass flow rate of blood entering the aorta 104 through the blood pump increases (e.g., during systole), the current required to operate the motor 108 increases. Therefore, this change in motor current can be used to help characterize cardiac function, as will be discussed further in relation to the following drawings. Detection of mass flow rate using motor current may be facilitated by positioning the motor 108 so that it is aligned with the natural direction of blood flow from the left ventricle 103 into the aorta 104. Detection of mass flow rate using motor current may also be facilitated by the small size and / or low torque of the motor 108. Although the motor 108 in Figure 1 has a diameter of approximately 4 mm, any suitable motor diameter may be used, provided that the rotor-motor mass is sufficiently small, has sufficiently low torque, and is positioned to respond quickly and easily to changes in the physiological pressure gradient across the pump. In some embodiments, the diameter of the motor 108 is less than 4 mm.

[0024] In certain embodiments, one or more motor parameters other than current are measured, such as the power delivered to the motor 108. In some embodiments, the motor 108 in Figure 1 operates at a constant speed. In certain embodiments, the speed of the motor 108 is varied over time (e.g., as a delta function, step function, sinusoid function, or ramp function) to explore the intrinsic cardiac function. In some embodiments, the motor 108 may be located outside the patient's body, and the rotor may be driven by an elongated mechanical transmission element, such as a flexible drive shaft, drive cable, or fluid coupler.

[0025] The pressure sensor 112 of the intravascular cardiac pump system 100 may be located at various positions on the pump, such as on the motor 108 or at the pump outlet 110. Placing the pressure sensor 112 at the pump outlet 110 allows the pressure sensor 112 to measure true aortic pressure (AoP) when the intravascular blood pump system 100 is positioned across the aortic valve 105. In certain embodiments, the pressure sensor 112 of the intravascular cardiac pump system 100 may be located on the cannula 111, on the catheter 106, or at any other preferred position. The pressure sensor 112 may detect blood pressure in the aorta 104 when the intravascular cardiac pump system 100 is properly positioned within the heart 102. Blood pressure information may be used to properly position the intravascular cardiac pump system 100 within the heart 102. For example, the pressure sensor 112 may be used to detect whether the pump outlet has passed through the aortic valve 105 and entered the left ventricle 103; in this case, the blood will only circulate within the left ventricle 103 and will not be transported from the left ventricle 103 to the aorta 104. In some embodiments, the pressure sensor 112 is a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometric sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor.

[0026] The intravascular cardiac pump system 100 may be inserted into the heart 102 by various means, such as percutaneous insertion. For example, the intravascular cardiac pump system may be inserted through the femoral artery (not shown in the figure), through the aorta 104, across the aortic valve 105, and into the left ventricle 103. In certain embodiments, the intravascular cardiac pump system 100 is surgically inserted into the heart 102. In some embodiments, the intravascular cardiac pump system 100, or a similar system adapted for the right heart, is inserted into the right heart. For example, a right heart pump similar to the intravascular cardiac pump system 100 may be inserted through the femoral vein into the inferior vena cava, bypassing the right atrium and right ventricle, and extending into the pulmonary artery. Alternatively, the right heart pump may be inserted through the internal jugular vein and superior vena cava, and the left heart pump may be inserted through the axillary artery. In certain embodiments, the intravascular cardiac pump system 100 may be configured to operate within the vascular system other than the heart 102 (e.g., within the aorta 104). By being minimally invasive and located within the vascular system, the intravascular cardiac pump system 100 has sufficient sensitivity to enable the characterization of the patient's own cardiac function.

[0027] Figure 2A shows an illustrative plot of the pressure gradient against motor current. Plot 200 has an x-axis 202 representing the motor current in mA and a y-axis 204 representing the pressure gradient (dP) in mmHg. Plot 200 includes a trend line 206 showing the relationship between motor current and pressure gradient. The motor current drawn by the blood pump is proportional to the pressure gradient across the blood pump cannula at a known motor speed. Plot 200 can serve as a lookup for algorithms to determine the pressure gradient from a given motor current and the motor speed at which the blood pump motor is currently operating. For example, a motor current of approximately 650 mA, indicated by point 208 on the x-axis, corresponds to a pressure gradient of 120 mmHg, indicated by point 210 on the y-axis; this is determined by drawing a line upward from point 208 of the motor current to trend line 206, and then drawing a line from the intersection with trend line 206 to point 210 on the y-axis. The relationship between motor current and pressure gradient, as illustrated by plot 200, may be determined in the laboratory under physiological conditions for a particular blood pump and may be stored in the memory of the processor within the blood pump controller.

[0028] The controller determines the pressure gradient associated with the motor current and motor speed under which the blood pump is currently operating by accessing plot 200. The controller may then use the pressure gradient, along with other determined or measured values ​​such as aortic pressure measured by a pressure sensor (e.g., pressure sensor 112 in Figure 1), to determine various cardiac parameters such as LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, heart rate, cardiac output, cardiac power, spontaneous cardiac output, spontaneous cardiac power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, and cardiac recovery index.

[0029] For example, if the pressure gradient across the blood pump cannula is determined from the motor current and motor speed, this pressure gradient across the blood pump cannula may be used in conjunction with the measured aortic pressure (such as the pressure measured at pressure sensor 112) to determine an estimate of the LVP at the pump's inlet cage. The LVP is estimated by subtracting the pressure gradient from the aortic pressure. As will be discussed later with respect to Figure 2B, the LVP determined in this manner is a very good estimate of the actual LVP in the heart. The estimated LVP may be displayed on a display screen by the controller, where it may be accessed and viewed by a clinical healthcare professional. The clinical healthcare professional may use the information provided by the LVP at a given moment, or a historical view of LVP changes, to make clinical decisions regarding patient care, including making informed decisions about changes to the support provided by the blood pump.

[0030] The relationship between the pressure gradient and the motor current of the blood pump at a known motor speed is illustrated as plot 200, but the controller may use the information contained in plot 200 by accessing a lookup table or by querying a function that describes the relationship between the pressure gradient and the motor current and motor speed. In some embodiments, the controller may include additional parameters other than motor current and motor speed in determining the pressure gradient across the blood pump cannula, such as other properties of the pump, properties of the pump controller or console, environmental parameters, and motor speed settings. Including additional parameters in the function used to determine the pressure gradient may lead to a more accurate correlation between motor current and differential pressure, which allows for a more accurate calculation of LVP or other cardiac parameters.

[0031] Figure 2B shows an illustrative plot illustrating the measured aortic pressure and calculated LVP as a function of time. Plot 201 has an x-axis 203 representing time in seconds and a y-axis 205 representing pressure head in mmHg. The plot has three traces, including aortic pressure 212, estimated LVP 214 (dotted line), and measured LVP 216. The traces on plot 201 show that the estimated LVP, determined from the measured aortic pressure and the determined pressure gradient across the blood pump cannula, matches the measured LVP value. The algorithm determines continuous LVP, including the entire waveform and LVP points within the cardiac cycle, based on the motor current and the measured aortic pressure. The algorithm measures LVP immediately inside the pump inlet 114; this allows the algorithm to determine suction events and distinguish between systolic / continuous suction and diastolic / intermittent suction.

[0032] LVEDP points within the cardiac cycle are important for calculating other cardiac parameters. The pressure at the end-diastolic point is the LVP immediately before left ventricular contraction, which can be defined by the onset of the R wave in a reference EKG measurement. LVEDP points within the cardiac cycle may be estimated based on the aortic pressure 212 implantation signal, the LVP 214 waveform, and the pressure gradient in the pump. In some embodiments, LVEDP is estimated based on the identification of a peak in the estimated LVP 214 waveform; this peak is then shifted on the time axis to estimate the LVEDP point. This technique is called peak detection and time indexing. In alternative embodiments, estimated LVEDP is calculated based on the first and / or second time derivatives of the estimated LVP 214 waveform over time.

[0033] Figure 2C shows an exemplary plot 220 of the estimated LVP 214 waveform and the aortic pressure 212 waveform over time. The plot has an x-axis 222 representing time and a y-axis 224 representing pressure head in mmHg. The plot includes a trace 226 (dotted line) of the estimated LVP waveform and a trace 228 (solid line) of aortic pressure. In some embodiments, an LVEDP may be selected based on plot 220 by selecting a peak in the estimated LVP waveform 226 and shifting its point over time. For convenience, only one LVEDP point 229 is shown in this plot 220, but an LVEDP may be calculated for each period of the LVP waveform to monitor changes over time.

[0034] Figure 2D shows an exemplary plot 230 of the first derivative of the estimated LVP waveform 214 with respect to time. Plot 230 may also be calculated as the derivative of the LVP waveform 226 in plot 220. Plot 230 has an x-axis 232 representing time and a y-axis 234 representing the first derivative of pressure (dP / dt) with respect to time in mmHg / sec. The plot includes a trace 236 of the first derivative of the LVP waveform and an index of an LVEDP point 238, which may be selected as the estimated LVEDP based on the trace 236 of the first derivative of the LVP waveform. Point 238 indicates a point associated with LVEDP; it may be calculated, for example, as a point midway between the smallest trough and the largest peak of the first derivative 236 of the LVP waveform. For convenience, only one LVEDP point 238 is shown in this plot 230, but LVEDP may be calculated for each period of the LVP waveform. Alternatively, plotting the first derivative 236 of the LVP waveform 230 may be useful in “windowing” or narrowing the search for LVEDP point 238; LVEDP point 238 may then be determined based on the second derivative plot or other means. Estimation of LVEDP point 238 based on plot 230 may be sensitive to sampling frequencies with higher sampling frequencies, such that higher sampling frequencies result in a more accurate calculation of LVEDP point 238.

[0035] Figure 2E shows an illustrative plot 240 of the second derivative of the estimated LVP 214 waveform with respect to time. Plot 230 may be calculated as the derivative of the LVP waveform 236 in plot 230, or as the second derivative of the LVP waveform 226 in plot 220. Plot 240 has an x-axis 242 representing time and the second derivative of pressure with respect to time (d 2 PDT 2 ) mmHg / second 2The plot has a y-axis 244 represented by . The plot includes a trace 246 of the second derivative of the LVP waveform and an index 248 of an LVEDP point which may be selected as an estimated LVEDP based on the trace 246 of the second derivative of the LVP waveform. Point 248 indicates a point associated with LVEDP; it may be calculated, for example, as the point where the second derivative 246 of the estimated LVP waveform has the largest peak. For convenience, only one LVEDP point 248 is shown in this plot 240, but LVEDP may be calculated for each period of the LVP waveform. Similar to the estimation of LVEDP point 238 based on the plot 230 of the first derivative, the estimation of LVEDP point 248 based on the plot 240 of the second derivative may be sensitive to the sampling frequency and more accurate at higher sampling frequencies.

[0036] The peaks of the first or second time derivatives of the LVP waveform may be used to accurately calculate LVEDP points. Furthermore, the peaks and troughs of the first and second time derivatives of the LVP waveform may be used to narrow the search window for a given LVEDP point, thereby reducing false positives and improving LVEDP point detection. Using the first or second time derivatives of the measured aortic pressure 212 to determine LVEDP allows the algorithm to more accurately determine LVEDP points within the cardiac cycle. Alternatively, the aortic pressure waveform (e.g., 212 in Figure 2B) may also be used, along with the first and second derivatives of the aortic pressure waveform, to determine LVEDP points.

[0037] Figure 3 shows an exemplary user interface for a cardiac pump controller displaying waveforms of cardiac function over time. The user interface 300 may be used to control the intravascular cardiac pump system 100 of Figure 1 or any other suitable cardiac pump. The user interface 300 includes a pressure signal waveform 302, an LVP waveform 303, a motor current waveform 304, a flow rate 306, a measure of cardiac output 308, and a measure of spontaneous cardiac output 310. The pressure signal waveform 302 shows the pressure measured by a pressure sensor on the blood pump (e.g., pressure sensor 112) and corresponds to the aortic pressure when the pump is properly positioned. The pressure signal waveform 302 and the LVP waveform 303 may be used by a healthcare professional to properly position the intravascular cardiac pump (such as the intravascular cardiac pump 100 in Figure 1) within the heart. The pressure signal waveform 302 is used to verify the location of the intravascular cardiac pump by evaluating whether the waveform 302 is an aortic waveform or a ventricular waveform. An aortic waveform indicates that the intravascular cardiac pump motor is located within the aorta. A ventricular waveform indicates that the intravascular cardiac pump motor has been inserted to an incorrect position within the ventricle. A scale 312 for the implantation signal waveform is displayed to the left of the waveform. The default scaling is 0 to 160 mmHg. The scaling may be adjusted in 20 mmHg increments, for example, scale 312 is shown with a scaling of -20 to 160 mmHg. To the right of the waveform is a display 314 that labels the waveform, provides units of measurement, and includes an index of the current estimated pressure. Display 314 may also include an estimated aortic pressure 316 and / or an estimated LVP 318, which may be instantaneous estimates, mean values, maximum values, or minimum values, and may also include indices of other cardiac parameters calculated from the pressure signal waveform, such as LVEDP. In some embodiments, display 314 shows the maximum, minimum, and mean values ​​derived from the calculated cardiac meter values. By including the pressure signal waveform 302, the LVP waveform 303, and the display 314, the pressure signal and LVP are displayed as a function of time, and important cardiac parameters are extracted and displayed in the display 314.

[0038] In some embodiments, variability between different blood pumps is taken into account by calibrating the LVP waveform 303 to the measured aortic pressure waveform 302. The user may be prompted by the display to manually adjust the peak of the estimated LVP waveform (e.g., 214 in Figure 2B) along the y-axis to match the peak of the aortic pressure waveform (e.g., 212 in Figure 2B). In some embodiments, the calibration may be automated for the user based on pressure readings of the aortic pressure and LVP waveforms. In other embodiments, the necessary calibration may be calculated by a controller within the user interface 300, and a prompt with instructions to align the peak of the systolic LVP waveform to the same peak in the aortic pressure waveform may be presented to the user, including suggested values ​​based on the controller's calculations for the same alignment in the background of the program. The controller can also detect the exact point in the cardiac cycle where the aortic pressure and LVP waveforms should overlap by calculating its alignment in the background. The overlap between the aortic pressure and LVP waveforms corresponds to the opening and closing of the aortic valve. These events indicate the start and end of systole. Determining the overlap point between the aortic pressure waveform and the LVP waveform is difficult visually, but it may be calibrated by a controller to improve calibration that requires identification of peaks in the LVP and aortic pressure waveforms.

[0039] Automating the calibration procedure simplifies the use of the user interface 300 and ensures that the user is presented with appropriate calibration values. Calibration calculation may be further improved at higher sampling frequencies.

[0040] The motor current waveform 304 is a measure of the energy intake of the cardiac pump motor. Energy intake fluctuates with motor speed and the pressure difference between the inlet and outlet areas of the cannula, which results in changes in volumetric load on the rotor. When used with an intravascular cardiac pump (such as intravascular cardiac pump 100 in Figure 1), the motor current provides information about the catheter's position relative to the aortic valve. When the intravascular cardiac pump is correctly positioned with the inlet area in the ventricle and the outlet area in the aorta, the motor current is pulsatile because the mass flow rate through the cardiac pump changes with the cardiac cycle. When the inlet and outlet areas are on the same side of the aortic valve, the pump's inlet and outlet are located in the same chamber, resulting in no fluctuation in differential pressure, and consequently, a constant mass flow rate and therefore a constant motor current, so the motor current weakens or flattens out. A scale 320 for the motor current waveform is displayed to the left of the waveform. The default scaling is 0-1000 mA. Scaling may be adjustable in 100 mA increments. To the right of the waveform is a display 322 that labels the waveform, provides units of measurement, and shows the maximum, minimum, and mean values ​​derived from the received sample. Pressure and motor current sensors may not be necessary for surgically implanted pump placements, but may also be used in such devices to determine additional characteristics of the patient's own cardiac function in order to monitor treatment.

[0041] Although only three waveforms (pressure signal waveform 302, LVP waveform 303, and motor current waveform 304) are shown in Figure 3, additional waveforms may be displayed on the main screen of the display 300 or accessible on an additional screen. For example, a contractile force waveform, a cardiac state waveform, an ECG waveform, or any other appropriate cardiac parameter that changes with time or pulse may be displayed on the display 300. Displaying cardiac information as a trend line allows a physician to view the patient's chronological cardiac state and make decisions based on visible trends. For example, a physician may observe a decrease or increase in aortic pressure over time, as shown in the pressure signal waveform 302, and decide to modify or continue treatment based on that observation.

[0042] The locations, depictions of the meter values ​​on the controller, and the identification and number of meter values ​​and recommendations in Figure 3 are illustrative. The number of meter values ​​and indicators, their locations on the console, and the meter values ​​displayed may differ from those shown herein. Cardiac parameters displayed to the user may include, for example, LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, heart rate, cardiac output, cardiac output, spontaneous cardiac output, spontaneous cardiac output, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. In some embodiments, the font, font size, layout, and arrangement of the user-displayed parameters may be configured for ease of use in critical care situations.

[0043] The scale of the spontaneous cardiac output (SCO) 310 may include a representation of NCO in units of L / min, calculated based on the measured cardiac parameters. Spontaneous cardiac output is a measure of blood flow by the heart itself, or the flow rate of blood in the vascular structure surrounding the blood pump. Spontaneous cardiac output is calculated from the indwelling signal (aortic pressure) 316 and the pulse pressure calculated by the controller by subtracting the minimum aortic pressure from the maximum aortic pressure. The pulse pressure may be calculated periodically by the controller. Spontaneous cardiac output may be used to calculate additional clinically relevant cardiac parameters. For example, spontaneous cardiac output may be used in conjunction with information on blood pump flow rate to calculate the total cardiac output of the heart itself and the blood pump.

[0044] The cardiac output scale 308 may include a representation of total cardiac output in watts, calculated based on measured cardiac parameters. Total cardiac output is calculated from total cardiac output, which is calculated based on spontaneous cardiac output as described above. Total cardiac output is calculated by multiplying cardiac output by mean arterial pressure and dividing by 451.

[0045] The flow rate 324 may be a target blood flow rate set by the user, or an estimated actual flow rate. In some modes of the controller, the controller automatically adjusts the motor speed in response to changes in afterload to maintain the target flow rate. In some embodiments, if flow rate calculation is not possible, the controller allows the user to set a fixed motor speed indicated by a speed indicator.

[0046] Memory within the user interface or controller records data measured, calculated, and displayed on the controller. The memory may have a sampling rate of 25–150 Hz. In some embodiments, higher sampling rates, such as 100 Hz or higher, are preferred because data is recorded in the data log in memory at a faster rate. Higher-fidelity data recorded in memory may be used to better estimate cardiac function over time. Waveforms, algorithms, and alarms displayed to the user on the user interface may be displayed at a lower speed for efficiency.

[0047] The display 300 includes various buttons 326–334 for accessing additional display screens. These buttons include a menu button 326, a purge menu button 328, a display button 330, a flow control button 332, and a mute alarm button 334. The buttons shown on the display 300 are illustrative, and alternative or additional buttons may be accessible to the user. The menu button 326 may allow the user to access additional information about the use of the display 300, including software version, registration details, and usage date. The menu button 326 may also allow the user to access options such as the power mode of the display 300 or locking the display 300. The menu button 326 may also allow the user to calibrate the display 300, or allow the user to access options or instructions for calibrating the display 300 in relation to an attached blood pump. For example, the user may calibrate cardiac parameters displayed as measured pressure values ​​or waveforms against known values ​​of cardiac parameters measured by an arterial catheter or similar device. The purge menu button 328 may allow the user to access additional usage options, settings, and information regarding the purge system of the installed blood pump. The display menu button 330 may allow the user to access additional cardiac meter values ​​and parameters, and in some cases, to add or change cardiac meter values ​​displayed on the main screen of the display 300. The flow control button 332 may allow the user to access additional options and settings regarding controlling the pump flow rate by adjusting the pump motor speed. The flow control button may also allow the user to access recommendations regarding the current pump motor speed and various cardiac meter values ​​calculated by the controller, and may allow the user to input or accept adjustments to the pump motor speed.A mute alarm button 334 may allow the user to silence the alarm or access additional information about an alarm or warning issued by the controller. The controller may issue warning notifications to the user regarding the use of the display, blood pump, and associated systems, or cardiac measurements calculated by the controller. Warnings and alarms may be audible alarms or pop-up screens on the display 300, or they may be sent directly to a clinical healthcare professional, for example, via text, page, or email.

[0048] In some embodiments, a warning or alarm is triggered when a cardiac metric value calculated, measured, or monitored by the controller falls below a set threshold. In some embodiments, a warning or alarm is triggered when a cardiac metric value calculated, measured, or monitored by the controller exceeds a set threshold. In some embodiments, a warning or alarm is triggered when there is a change in the cardiac metric value calculated, measured, or monitored by the controller that exceeds or falls below a set threshold. In some embodiments, the set threshold is a system value set within the controller. In some embodiments, the set threshold is set by a clinical healthcare professional based on the patient's history and health status. In some embodiments, the set threshold is a prior value of the cardiac metric, such as a prior value measured or calculated a predetermined time ago.

[0049] In some embodiments, a warning or alarm is a recommendation to modify the assistance provided to the heart by the blood pump based on one or more calculated, measured, or monitored cardiac metrics. Figures 4–11 illustrate the process by which the controller determines various recommended changes to the cardiac assistance provided by the blood pump.

[0050] Figure 4 shows a process 400 for optimizing the performance of the blood pump within the heart based on measured and calculated cardiac parameters.

[0051] In step 402, the motor of the heart pump is operated at a certain rotational speed. In step 404, the aortic pressure is measured. The aortic pressure may be measured by a pressure sensor connected to the heart pump, by a separate catheter, by a non-invasive pressure sensor, or by any other suitable sensor. The pressure sensor may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometry sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor. In some embodiments, ventricular pressure is measured as an addition to or alternative to the measurement of aortic pressure. In step 406, the current delivered to the motor is measured, and the motor speed is measured. In step 408, the differential pressure across the cannula of the blood pump is determined based on the measured motor current and motor speed; this determination is made by using a lookup table or by accessing a function that describes the motor current measured at a known speed and optionally other parameters. In step 410, cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure. The cardiac parameters may be one of the following: LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. Each of these cardiac parameters may be used by a clinical healthcare professional as a measure of various aspects of cardiac health and function. Trends in each cardiac parameter over time may be used by a clinical healthcare professional to determine whether spontaneous cardiac output is improving or decreasing, and clinical decision-making regarding the support provided by the blood pump and drug therapy may be based on these trends. In some embodiments, two or more cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure.

[0052] Specifically, one or more of LVP and LVEDP may be calculated according to an algorithm to evaluate the performance of the blood pump within the patient's heart. In some embodiments, the calculated metric values ​​are evaluated by a processor to determine if there are any problems with the current performance of the blood pump and to provide the user with suggestions for correcting those problems. In some embodiments, the metric values ​​are presented for evaluation by a healthcare professional.

[0053] In step 412, the calculated cardiac parameters are recorded in memory. By accessing the recorded cardiac parameters stored in memory, a historical view of cardiac parameters over time may be accessed by the user, or it may be displayed as a trend line on the display console.

[0054] In step 414, cardiac function parameters are determined based on the calculated cardiac parameters. These cardiac function parameters may be any of the following: cardiac output, cardiac power, spontaneous cardiac output, spontaneous power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. These cardiac function parameters may be derived from the calculated cardiac parameters and other available measurement parameters. The cardiac function parameters provide clinicians with additional information about cardiac function and the performance of the blood pump in relation to cardiac function. In some embodiments, the cardiac function parameters are also recorded in memory to provide historical data and trends in the cardiac function parameters over time. In some embodiments, two or more cardiac function parameters are determined.

[0055] For example, cardiac output may be calculated based on the motor current and motor speed of the blood pump and the measured aortic pressure. From the aortic pressure, the pulse pressure of the aortic waveform may be derived. In embodiments where the pressure sensor (e.g., pressure sensor 112 in Figure 1) is located at the pump outflow, the aortic pressure and the pulse pressure of the aortic waveform are measured at the aortic root; this site is less affected by aortic resistance, systemic resistance, and systemic vascular compliance compared to pulse pressure calculation by peripheral approaches (e.g., PiCCO, Edwards FloTract). In some embodiments, the pulse pressure, and thus the algorithm-calculated value, is affected by aortic compliance at the measurement point, which varies from patient to patient. However, patient-to-patient variability can be taken into account by calibrating the cardiac output algorithm, and since the properties of the aortic root wall are typically not affected by vasoactive and inotropic agents, the variation in aortic compliance within a patient during the period of support is considered to be very small. Other cardiac output algorithms that rely on pulse pressure and the derivative of the pulse pressure wave (e.g., PiCCO, FloTract, or PulseCo) cannot distinguish between beatings caused by the intrinsic heart and those caused by assistive devices. In contrast, this algorithm can distinguish between intrinsic beatings and those caused by pumps, and can decouple changes in beatings caused by flow changes originating from either the pump or the heart.

[0056] In step 416, the calculated cardiac parameters and / or cardiac function parameters are generated for display and shown to the user on the display interface. The calculated cardiac parameters may be accessed in the controller's memory and processed to prepare them for display as numerical values, waveforms over time, or maximum or minimum values. The cardiac parameters and cardiac function parameters may be displayed on a display, such as display 300 in Figure 3, for clinical healthcare professionals, for example, a laboratory technician or a nurse in an intensive care unit or catheterization lab. The calculated cardiac parameters, cardiac function parameters, and optionally, a historical view of cardiac parameters and / or cardiac function parameters over time, enable clinical healthcare professionals to view trends in cardiac parameters and cardiac function parameters and make decisions based on them. To illustrate the use of the algorithm derived by this algorithm to determine the correct location of a blood pump, an example of a user interface is shown in Figure 5.

[0057] The display and / or determination of cardiac parameters and cardiac function parameters may be performed continuously or nearly continuously while the cardiac pump is implanted in the heart. This may be advantageous over conventional catheter-based methods, which can only sample cardiac function at specific or discontinuous points in time during the cardiac cycle. For example, continuous monitoring of cardiac parameters may allow for more rapid detection of cardiac deterioration. Continuous monitoring of cardiac parameters and cardiac function parameters can show changes in the condition of the heart over time. In addition, if a cardiac assist device is already in the patient's body, cardiac function can be measured without the need to introduce an additional catheter into the patient. Cardiac parameters and / or cardiac function parameters may be displayed as shown in the user interface of Figure 3, or using any other preferred user interface or report.

[0058] In step 418, optimization of blood pump performance is determined based on the calculated cardiac parameters and cardiac function parameters. The controller may access the calculated cardiac parameters in memory and compare the calculated cardiac parameters or cardiac function parameters to stored thresholds to determine that blood pump performance can be optimized with respect to the patient's cardiac function. For example, the controller may determine that the patient's cardiac function has improved and the patient can be weaned off blood pump assistance. Alternatively, the controller may determine that the patient's cardiac function has deteriorated and the blood pump assistance provided to the patient should be increased. Additionally or alternatively, the controller may determine, based on the current placement of the blood pump, that there is a risk of aspiration or an aspiration event and that the placement of the blood pump can be optimized. The thresholds used to compare the calculated cardiac parameters or cardiac function parameters may be preset at the time of manufacture, set by a physician via the user interface, or based on previous readings of the patient's calculated cardiac parameters and cardiac function parameters. For example, the controller may compare the calculated LVP to a threshold to determine that there is a risk of aspiration due to the current placement of the blood pump. In some embodiments, the controller compares the LVP waveform with one or more stored waveforms. In some embodiments, the controller compares the minimum and / or maximum points derived from the LVP waveform with stored thresholds.

[0059] In step 420, a notification regarding the determined optimizations for the blood pump performance is generated and displayed. The notification may be accessed from memory within the controller and may be generated according to the determined optimizations and for display. The notification regarding the blood pump performance optimization may be displayed within the user interface of Figure 3. In some embodiments, the notification regarding the blood pump performance optimization is displayed on the main screen. In some embodiments, the notification regarding the blood pump performance optimization is displayed as a pop-up or warning. The notification may suggest increasing or decreasing the blood pump motor speed, or indicate that there is a placement problem or a risk of aspiration events. In some embodiments, the notification may further provide recommendations to address placement problems or aspiration events, such as recommending increasing or decreasing the blood pump motor speed, or moving the blood pump a certain distance in a particular direction. In some embodiments, the recommended change in motor speed may exceed the speed of the blood pump currently in use, and the notification may recommend changing the type of blood pump.

[0060] In some embodiments, the displayed notification is interactive, and the controller may take action regarding the recommended motor speed change based on input from the clinical healthcare professional. In other embodiments, the notification may indicate that the recommended motor speed change has already been automatically performed by the controller.

[0061] Figure 5A shows a user interface 500 for a cardiac pump controller illustrating intermittent or diastolic suction events in a blood pump. User interface 500 includes components similar to user interface 300; however, for simplicity, not all components are labeled or shown here. User interface 500 includes a first plot 505 showing aortic pressure waveform 504 and LVP waveform 506, and a second plot 507 showing motor current waveform. The user interface also includes an aortic pressure index 508 on the aortic pressure waveform 504, including minimum and maximum values, and an LVP index 512 on the LVP waveform 506, including minimum and maximum values. An index 510 of the current motor speed, a warning pop-up 514, and instructions or recommendations 516 for dealing with the warning pop-up are also included in user interface 500.

[0062] The aortic pressure waveform 504 and LVP waveform 506, measured by the controller based on pressure readings and the motor current of the blood pump, are useful in detecting intermittent diastolic suction events in the blood pump caused by insufficient blood volume in the heart. During such suction events, the LVP waveform 506 drops below zero in the first plot 505 in early diastole but recovers by the end-diastolic pressure point. The systolic phase of the LVP waveform 506 is normal. During intermittent diastolic suction events, the maximum LVP index 512 is typically normal and greater than the maximum aortic pressure index 508, while the minimum LVP index 512 is abnormal and very low or below zero; therefore, these events may also be detected by the LVP index 512 and the aortic pressure index 508. Thus, the minimum value of the LVP index 512 provides an early indicator of diastolic suction. The controller may issue a warning 514 based on a comparison of the minimum value of the LVP index 512 with a threshold, such as 0 mmHg, -10 mmHg, -20 mmHg, -30 mmHg, -40 mmHg, or any other preferred threshold. In some embodiments, the comparison of the minimum values ​​of the LVP index 512 may be used to determine the level of risk or the severity of the aspiration event, for example, 0 mmHg indicating borderline or low risk, -10 mmHg indicating mild aspiration risk, and -20 mmHg indicating moderate aspiration risk. The controller may further provide recommendations 516 for physicians, nurses, or technicians on how to respond to warning 514 in order to address and correct the aspiration event. For example, the controller may provide recommendations to check additional cardiac measurements to determine the cause of the aspiration event, or to check the patient's health status before adjusting the blood pump placement or cardiac support level. The controller may also provide instructions or recommendations to check the placement of the blood pump based on the detection of aspiration events, and may further recommend changing the level of assistance provided by the blood pump by changing the motor current 510.

[0063] Figure 5B shows a user interface 501 for a cardiac pump controller illustrating a continuous suction event in a blood pump. Similar to user interface 500 in Figure 5A, user interface 501 includes components similar to user interface 300; however, for simplicity, not all components are labeled or shown here. User interface 501 includes a first plot 525 showing the aortic pressure waveform 524 and the LVP waveform 526, and a second plot 527 showing the motor current waveform. The user interface also includes an aortic pressure index 528 on the aortic pressure waveform 524, including minimum and maximum values, and an LVP index 532 on the LVP waveform 526, including minimum and maximum values. An index 530 of the current motor speed, a warning pop-up 534, and instructions or recommendations 536 for dealing with the warning pop-up are also included in user interface 501.

[0064] Similar to the process in Figure 5A where intermittent (diastolic) suction events are determined and indicated by the displayed LVP and aortic pressure, the determination of continuous or systolic suction events is also informed by the LVP waveform 526, aortic pressure waveform 524, LVP index 528, and aortic pressure index 532. By displaying these and other cardiac metrics to the user via the user interface 501, users such as clinical healthcare professionals or physicians can recognize continuous suction events and respond appropriately to address them. Continuous suction events are typically caused by poor placement of the blood pump or by the structure of the heart blocking the blood pump inlet (e.g., the pump inlet 114). During a continuous suction event, the LVP waveform 526 drops below zero during diastole and never rises above the aortic pressure waveform 524 during systole. In addition, during continuous suction events, the maximum value of the LVP index 532 is abnormal and typically much lower than the maximum value of the aortic pressure index 528, while the minimum value of the LVP index 532 is abnormal and less than zero. The LVEDP calculated from the LVP waveform 526 is equal to zero, if displayed.

[0065] Similar to the case of intermittent (diastolic) suction events in Figure 5A, warning 534 and recommendation 536 may be displayed when a continuous suction event is detected. Recommendation 536 displayed when a continuous suction event is detected may be the same as or different from recommendation 516 displayed during intermittent suction events.

[0066] Figure 5C shows a user interface 502 for a cardiac pump controller illustrating a metered value trend screen. The trend screen includes a first plot 540 displaying trend waveforms 542 for cardiac output, 544 for blood pump flow rate, and 546 for spontaneous cardiac output, as well as relevant values ​​such as cardiac output, blood pump flow rate, and spontaneous cardiac output for rapid assessment by a physician. The metered value trend screen of user interface 502 also includes a second plot 548 displaying trend waveforms 550 for mean aortic pressure and 552 for LVEDP, as well as relevant values ​​such as mean aortic pressure 554 and LVEDP 556. User interface 502 also includes an index 560 for the blood pump motor speed, 562 for blood pump flow rate, 564 for cardiac output, and 558 for cardiac output.

[0067] The metric trend screen of user interface 502 can be accessed by physicians to further visualize historical data associated with various cardiac parameters over time. Such historical data can help physicians understand the progression of a patient's cardiac health and identify events that are occurring. For example, the metric trend screen of user interface 502 shown in Figure 5C displays the trend waveform 542 for cardiac output, trend waveform 544 for blood pump flow, trend waveform 546 for spontaneous cardiac output, trend waveform 550 for aortic pressure, and trend waveform 552 for LVEDP, all of which are relatively stable over time. However, changes or trends in these waveforms over time may indicate an aspiration event or risk of aspiration. The LVEDP trend waveform 552 should be stable throughout the process of providing cardiac support to the patient. A low and / or declining LVEDP trend waveform 552 indicates an increased risk of diastolic aspiration. Making this waveform easily accessible to physicians allows them to monitor the risk of aspiration events. To determine the cause of aspiration, the physician may examine the metering trend screen on the user interface 502; on this screen, a high LVEDP trend waveform 552 followed by a sudden drop to zero suggests a continuous or systolic aspiration event, while a low LVEDP trend waveform 552 stagnating near zero suggests an intermittent or diastolic aspiration event. The display of these trends and values ​​is made possible by the controller's algorithm calculating metering values ​​from the blood pump motor current and aortic pressure, allowing the physician to make informed decisions about patient care based on these values ​​and trends.

[0068] Displaying the average values ​​of various waveforms and cardiac measurements not only provides an indicator of aspiration events, but may also provide physicians with information that enables them to determine blood pump placement errors. For example, a physician or technician may determine that the blood pump has moved to the left ventricle and is therefore no longer providing adequate support by observing the change in the LVP waveform (e.g., 506 in Figure 5A or 526 in Figure 5B) relative to the aortic pressure waveform (e.g., 504 in Figure 5A or 524 in Figure 5B). When the blood pump moves to the left ventricle, the change in the shape of the LVP waveform provides instantaneous feedback that a placement error has occurred. By comparing the maximum and minimum values ​​of LVP with the maximum and minimum values ​​of aortic pressure, it can be shown to the physician that the aortic pressure value has begun to reflect the left ventricle signal instead of the aortic pressure. Meanwhile, LVEDP remains stable; this confirms that although the pump has moved, there are no ventricular structures obstructing the flow area.

[0069] Waveform display may also be useful during the repositioning of the pump that has moved to the left ventricle. Separate LVP and aortic pressure waveforms may be viewed to confirm a clear aortic pressure signal and may provide instantaneous feedback to the physician or technician during repositioning. Comparison of LVP and aortic pressure indices may also be viewed and may confirm the repositioning of the blood pump when the aortic pressure value differs from the LVP value.

[0070] In addition to displaying waveforms and cardiac meter readings, the user interface may provide warnings and / or recommendations if a problem with the blood pump placement is detected. Recommendations may include suggestions to reduce pump flow rate or motor speed, and to access repositioning guides.

[0071] In addition to displaying cardiac waveforms and values ​​that can be shown to a physician regarding suction events and placement issues, calculated cardiac parameters and quantified values ​​may also provide information for weaning decisions. Figure 5D shows a user interface 504 for a cardiac pump controller illustrating changes in cardiac function during weaning, as captured by the displayed quantified values. The user interface includes a first plot 575 showing aortic pressure waveform 574 and LVP waveform 576, and a second plot 577 showing motor current waveform. The user interface also includes an aortic pressure index 578 on the aortic pressure waveform 574, including minimum, maximum, and mean values, and an LVP index 582 on the LVP waveform 576, including minimum, maximum, and end-diastolic (LVEDP) values. An index of current motor speed 580, an index of blood pump flow rate 588, an index of cardiac output 586, and an index of cardiac output 584 are also included in the user interface 504.

[0072] The LVP waveform 576 and aortic pressure waveform 575 shown in Figure 5D exemplify those of a recovered patient with stable hemodynamics. LVEDP should be stable during the weaning process as the spontaneous heart takes over function and the excess left ventricular volume is eliminated. Cardiac output should also be stable during weaning as the spontaneous heart takes over pumping output; and cardiac output should also be stable and preferably within the range required by the specific institution's decision protocol. The weaning progression in a recovered patient may also be visualized on the metric trend screen; in this case, as support from the blood pump decreases over time, an increase in spontaneous cardiac output (e.g., 546 in Figure 5C) occurs along with a decrease in blood pump flow rate (e.g., 544 in Figure 5C). During the weaning process, the spontaneous heart takes over function from the blood pump and cardiac output (e.g., 542 in Figure 5C) remains stable. When the own heart takes over, LVEDP (e.g., 552 in Figure 5C) is stable or decreases, and cardiac output (e.g., 558 in Figure 5C) is stable.

[0073] In patients with deteriorating condition, the heart is unable to pump the excess blood volume, and left ventricular volume increases, making it likely that LVEDP will rise during weaning attempts. At this time, the LVEP waveform 576 and aortic pressure waveform 574 may decrease. In diseased patients, cardiac output 586 and cardiac output 584 also decrease during weaning because the spontaneous heart cannot compensate for the reduced support from the blood pump. Functional decline during weaning in diseased patients can also be visualized on the metric trend screen; in this case, spontaneous cardiac output (e.g., 546 in Figure 5C) may decrease over time as the patient's dependence on blood pump support increases. The LVEDP waveform (e.g., 552 in Figure 5C) may rise because the heart is unable to pump blood and LVEP increases. Cardiac output (e.g., 558 in Figure 5C) decreases, and whole beat output is also lower.

[0074] Figure 6 shows a process 600 for determining cardiac output and displaying recommendations for adjusting pump assistance to the user. Process 600 may be performed using the intravascular cardiac pump system 100 of Figure 1 or any other suitable cardiac pump. In order to monitor the trend of quantified values ​​during the weaning process and to assess the patient's readiness to wean the heart from blood pump assistance, cardiac output and its historical trend over time may be interpreted and evaluated by the physician in an intensive care setting or catheterization lab. In addition, cardiac output, spontaneous cardiac output, and LVEDP may also be generated and displayed to the physician to inform decision-making regarding patient weaning.

[0075] To determine the patient's cardiac output, the algorithm proceeds according to the following process: In step 602, the motor of the cardiac pump is activated. The motor may be operated at a constant rotational speed. In step 604, the aortic pressure is measured. The aortic pressure may be measured by a pressure sensor connected to the cardiac pump, by a separate catheter, by a non-invasive pressure sensor, or by any other suitable sensor. The pressure sensor may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometry sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor. In some embodiments, ventricular pressure is measured as an addition to or alternative to the measurement of aortic pressure.

[0076] In step 606, the current supplied to the motor is measured, and the motor speed is also measured. The current may be measured using a current sensor or by any other suitable means.

[0077] In step 608, the pulse pressure waveform is calculated from the aortic pressure waveform by subtracting the minimum aortic pressure from the maximum aortic pressure. The mean aortic pressure may also be extracted from the mean aortic pressure waveform. In step 610, spontaneous cardiac output is derived from the pulse pressure. To calculate spontaneous cardiac output, the relationship between pulse pressure and spontaneous cardiac output must first be determined using a linear scaling factor. The scaling factor is specific to both the patient and the condition and can be derived from an internal or external calibration method. In step 612, the pump flow rate is derived from the measured motor current and motor speed. In step 614, total cardiac output is determined by adding the pump flow rate to the spontaneous cardiac output. In step 616, cardiac output is calculated from total cardiac output and mean aortic pressure.

[0078] In step 618, recommendations for adjusting pump assistance to the heart are determined based on the calculated heart rate output. For example, if the calculated heart rate output, or a comparison of the calculated heart rate output with a threshold or historical value, indicates an improvement in the patient's cardiac function, a recommendation to reduce pump assistance to wean the patient off cardiac assistance may be determined. In another embodiment, if the calculated heart rate output, or a comparison of the calculated heart rate output with a threshold or historical value, indicates a deterioration in cardiac function, a recommendation to increase pump assistance to the patient may be determined. Finally, in step 620, the recommendations for adjusting pump assistance are generated for display and displayed on the user interface. In some embodiments, the heart rate output, and additionally, other calculated metrics and parameters, are also generated for display and displayed along with the recommendations for adjusting pump assistance. The calculated heart rate output, and optionally, a historical view of heart rate output over time, allows clinical healthcare professionals to view trends in heart rate output and make decisions based on them, for example, to make decisions regarding weaning a patient off blood pump assistance. Displaying these metric trends may help clinical healthcare professionals evaluate the displayed adjustment recommendations and assist in decisions regarding withdrawal or other changes to the level of support provided by the blood pump.

[0079] Cardiac power is the product of cardiac output and mean aortic pressure, and is a true measure of the power generated by the heart and pump immediately distal to the aortic valve. This can be measured based on the placement of pressure sensors in the pump outflow of the blood pump and an understanding of the operation of the blood pump in relation to cardiac parameters. Since spontaneous cardiac power represents the power generated by the heart itself, clinicians can use it as a measure of the overall health of the heart. Trends in spontaneous cardiac power may be used by clinicians to determine whether spontaneous cardiac output is improving or decreasing, and clinical decisions regarding the support provided by the blood pump and drug therapy may be made based on these trends. Determining cardiac power using the algorithm described above is more reliable and accurate than conventional determination methods.

[0080] Figure 7 shows a process 700 for recommending adjustments to the motor speed based on measured and calculated cardiac parameters. Process 700 may be performed using the intravascular cardiac pump system 100 of Figure 1 or any other suitable cardiac pump. Process 700 includes steps 702-716, which are substantially similar to steps 402-416 in Figure 4. These steps are listed briefly here, but those skilled in the art will understand that the substitutes and additional details included in the descriptions of the corresponding steps in Figure 4 also apply to steps 702-716 in Figure 7.

[0081] Similar to process 400 in Figure 4, the motor of the heart pump is activated in step 702. The motor may be operated at a constant rotational speed. In step 704, the aortic pressure is measured. Similar to process 400 in Figure 4, the aortic pressure may be measured by a pressure sensor connected to the heart pump or by a separate catheter. The sensor may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometric sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor. In step 706, the current delivered to the motor is measured and the motor speed is measured. In step 708, the differential pressure across the cannula of the blood pump is determined based on the measured motor current and motor speed; as discussed with respect to process 400 in Figure 4, this determination is made by using a lookup table or by accessing a function that describes the measured motor current for a known motor speed and optionally other parameters.

[0082] In step 710, cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure. The cardiac parameters may be one of the following: LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. Each of these cardiac parameters may be used by a clinical healthcare professional as a measure of various aspects of cardiac health and function. Trends in each cardiac parameter over time may be used by a clinical healthcare professional to determine whether spontaneous cardiac output is improving or decreasing, and clinical decision-making regarding the support provided by the blood pump and drug therapy may be based on these trends. In some embodiments, two or more cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure.

[0083] In step 712, the calculated cardiac parameters are recorded in memory. By accessing the recorded cardiac parameters stored in memory, a historical view of cardiac parameters over time may be accessed by the user, or it may be displayed as a trend line on the display console.

[0084] In step 714, cardiac function parameters are determined based on the calculated cardiac parameters. These cardiac function parameters may be any of the following: cardiac output, cardiac power, spontaneous cardiac output, spontaneous power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. These cardiac function parameters may be derived from the calculated cardiac parameters and other available measurement parameters. The cardiac function parameters provide clinical healthcare professionals with additional information about cardiac function. In some embodiments, the cardiac function parameters are also recorded in memory to provide historical data and trends in cardiac function parameters over time. In some embodiments, two or more cardiac function parameters are determined.

[0085] In step 716, the calculated cardiac parameters and / or cardiac function parameters are generated for display and shown to the user. The calculated cardiac parameters and / or cardiac function parameters are accessed from memory and generated for display as numerical values, maximum and minimum values ​​over a period of time, and / or historical trends over time. The cardiac parameters and cardiac function parameters are then displayed for clinical healthcare professionals on a display, such as display 300 in Figure 3. The calculated cardiac parameters, cardiac function parameters, and optionally, historical views of cardiac parameters and / or cardiac function parameters over time enable clinical healthcare professionals to view trends in cardiac parameters and cardiac function parameters and make decisions based on them.

[0086] The display and / or determination of cardiac parameters and cardiac function parameters may be performed continuously or nearly continuously while the cardiac pump is implanted in the heart. This may be advantageous over conventional catheter-based methods, which can only sample cardiac function at specific or discontinuous points in time during the cardiac cycle. For example, continuous monitoring of cardiac parameters may allow for more rapid detection of cardiac deterioration. Continuous monitoring of cardiac parameters and cardiac function parameters can show changes in the condition of the heart over time. In addition, if a cardiac assist device is already in the patient's body, cardiac function can be measured without the need to introduce an additional catheter into the patient. Cardiac parameters and / or cardiac function parameters may be displayed as shown in the user interface of Figure 3, or using any other preferred user interface or report.

[0087] In step 718, recommended changes to the motor speed are determined based on the calculated cardiac parameters and cardiac function parameters. The recommended changes to the motor speed may be determined based on a comparison of the cardiac parameters and / or cardiac function parameters with a threshold. Subsequently, the cardiac parameters and / or cardiac function parameters, or the difference between the cardiac parameters or cardiac function parameters and a threshold, may be used to determine the required increase or decrease in pump flow rate, and this increase or decrease in pump flow rate may be used to determine the corresponding motor speed using a lookup table or other function.

[0088] In step 720, a recommended change to the motor speed is generated for display and displayed. The recommended change to the motor speed may be displayed within the user interface of Figure 3. In some embodiments, the recommended change to the motor speed is displayed on the main screen. In some embodiments, the recommended change to the motor speed is displayed as a pop-up or warning. In step 722, user input in response to the displayed recommended change to the motor speed is accepted. In step 724, the motor speed is adjusted according to the user input. The motor speed is adjusted by changing the power delivered to the motor. The motor speed may be adjusted to be faster or slower than the current motor speed in response to user input in response to the recommended change to the motor speed. The power delivered to the motor may be adjusted automatically by the controller or manually (e.g., by a medical professional). The level of support may be increased when the patient's cardiac function is deteriorating; or the level of support may be reduced when the patient's cardiac function is recovering, thereby allowing the patient to gradually wean off treatment. This allows the device to dynamically respond to changes in cardiac function to promote cardiac recovery. This can also be used to intermittently adjust pumping assistance and to diagnose how the heart responds, for example, whether the heart can take over pumping function from the cardiac pumping device.

[0089] Figure 8 shows a process 800 for recommending adjustments to the motor speed based on cardiac output and LVEDP. Process 800 may be performed using the intravascular cardiac pump system 100 of Figure 1 or any other suitable cardiac pump. Process 800 follows the steps of process 700 shown in Figure 7 for the specific case of determining recommendations for adjustments to the motor speed based on cardiac output and LVEDP. In step 802, the motor of the cardiac pump is activated. The motor may be operated at a constant rotational speed. In step 804, the aortic pressure is measured. The aortic pressure may be measured by a pressure sensor connected to the cardiac pump, by a separate catheter, by a non-invasive pressure sensor, or by any other suitable sensor. The pressure sensor may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric resistance strain gauge, an optical interferometry sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor. In some embodiments, ventricular pressure is measured as an addition to or alternative to the measurement of aortic pressure. In step 806, the current supplied to the motor is measured, and the motor speed is also measured. The current may be measured using a current sensor or by any other suitable means.

[0090] In step 808, the differential pressure across the blood pump cannula is determined based on the measured motor current and motor speed. The controller may access a lookup table, such as the lookup table based on the relationship between motor current and differential pressure for known motor speeds in Figure 2A. Alternatively, the controller may use a function that describes the relationship between differential pressure and motor current to determine the differential pressure across the blood pump cannula, associated with the measured motor current and known motor speed. The controller may also take into account various other parameters in determining the differential pressure, such as the characteristics of the blood pump, pump controller, or console, environmental parameters, and motor speed settings, in order to more accurately determine the pressure gradient across the cannula.

[0091] In step 810, LVEDP and cardiac output are determined based on the aortic pressure and the pressure gradient across the blood pump cannula. LVEDP is calculated by subtracting the pressure gradient across the cannula, determined from the motor current, from the aortic pressure, and by selecting the end-diastolic point from the cardiac cycle. Cardiac output is calculated by first determining the spontaneous cardiac output from the pulse pressure, then determining the total cardiac output based on the pump flow rate, and finally calculating the cardiac output using the cardiac output together with the mean arterial pressure. In some embodiments, if the blood pump is a right heart blood pump, the right ventricular pressure is determined.

[0092] In step 812, the recommended adjustment for the motor speed of the blood pump is determined. The recommended adjustment for the motor speed may be determined based on a comparison of LVEDP, cardiac output, cardiac output, and / or mean aortic pressure with a threshold. Subsequently, the compared cardiac parameters, or the difference between the compared cardiac parameters or cardiac function parameters and a threshold, may be used to determine the required increase or decrease in pump flow, and this increase or decrease in pump flow may be used to determine the corresponding motor speed using a lookup table or other function.

[0093] In step 814, recommended adjustments to the blood pump motor speed are generated and displayed for display. The recommended changes to the motor speed may be displayed within the user interface shown in Figure 3. In some embodiments, the recommended changes to the motor speed are displayed on the main screen. In some embodiments, the recommended changes to the motor speed are displayed as a pop-up notification or warning.

[0094] Figure 9 shows process 900 for recommending a higher flow rate treatment device based on measured and calculated cardiac parameters. Process 900 includes steps 902–918, which are substantially similar to steps 702–718 in Figure 7. These steps are briefly listed here, but those skilled in the art will understand that the substitutes and additional details included in the descriptions of the corresponding steps in Figure 7 also apply to steps 902–918 in Figure 9.

[0095] In step 902, the heart pump motor is activated. In step 904, the aortic pressure is measured. In step 906, the current delivered to the motor is measured, and the motor speed is also measured. In step 908, the differential pressure across the blood pump cannula is determined based on the measured motor current and measured motor speed. In step 910, cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure. In step 912, the calculated cardiac parameters are recorded in memory. The calculated cardiac parameters may be LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. In step 914, cardiac function parameters are determined based on the calculated cardiac parameters. Cardiac function parameters may be any of the following: cardiac output, cardiac power, spontaneous cardiac output, spontaneous cardiac power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. In step 916, the calculated cardiac parameters and / or cardiac function parameters are generated for display and shown to the user. Recorded cardiac parameters are accessed in memory and processed for display as instantaneous values, sets of maximum and minimum values ​​over a period of time, and / or historical trends over time. The recorded cardiac parameters are then shown to the user. In some embodiments, the calculated cardiac function parameters are also saved and shown as trends over time. In step 918, recommended changes to the motor speed are determined based on the calculated cardiac parameters and cardiac function parameters.

[0096] In step 920, the recommended change to the motor speed is compared to a threshold. The threshold may be a value associated with the blood pump that indicates the maximum or minimum operating motor speed. The recommended change to the motor speed is compared to the threshold to determine whether the current blood pump can operate at the required speed; and / or whether the current blood pump is the optimal blood pump for operating at the required speed.

[0097] In step 922, the appropriate blood pump for operating at the recommended motor speed is determined based on a comparison with a threshold. The appropriate blood pump may be determined by examining a lookup table containing the properties and characteristics of various available blood pumps. Calculated cardiac parameters and / or cardiac function parameters may also be taken into consideration in determining the appropriate blood pump for operating at the recommended motor speed. By taking into consideration the calculated cardiac parameters and / or cardiac function parameters, the controller may be able to make recommendations based not only on the recommended pump speed but also on the overall cardiac function and health. In some cases, it may not be prudent to change to a different blood pump due to the patient's low cardiac function. This can be prevented when it is not prudent to change the blood pump to adjust the motor speed, by taking into consideration the calculated cardiac parameters and cardiac function, or alternatively, by displaying a warning to the clinical healthcare professional along with the recommendation.

[0098] In step 924, the determined appropriate blood pump is generated and displayed for display. Cardiac parameters and cardiac function parameters may be displayed for the clinical healthcare professional on a display such as display 300 in Figure 3. In some embodiments, the recommended motor speed is also displayed. As described above, when different blood pumps are recommended, additional information or warnings may also be displayed for the clinical healthcare professional; these may prompt the clinical healthcare professional to follow the protocol or to make additional decisions about cardiac function and health before acting on the recommendation.

[0099] Figure 10 shows a process 1000 for recommending drug therapy based on measured and calculated cardiac parameters. For example, drug dosage settings, including inotropic and vasopressor drugs, may be monitored and determined based on an assessment of cardiac metrics such as cardiac output and mean aortic pressure. Furthermore, volume state and fluid responsiveness may be monitored by a longitudinal assessment of LVEDP. The process 1000 for recommending drug therapy includes steps 1002–1020, which are substantially similar to steps 702–720 in Figure 7. These steps are briefly listed here, but those skilled in the art will understand that the substitutions and additional details included in the descriptions of the corresponding steps in Figure 7 also apply to steps 1002–1020 in Figure 10.

[0100] In step 1002, the motor of the cardiac pump is activated. In step 1004, the aortic pressure is measured. In step 1006, the current delivered to the motor is measured, and the motor speed is also measured. In step 1008, the differential pressure across the blood pump cannula is determined based on the measured motor current and measured motor speed. In step 1010, cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure. The calculated cardiac parameters may be LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. In step 1012, the calculated cardiac parameters are recorded in memory. In step 1014, cardiac function parameters are determined based on the calculated cardiac parameters. Cardiac function parameters may be any of the following: cardiac output, cardiac power, spontaneous cardiac output, spontaneous cardiac power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. In some embodiments, cardiac function parameters are also stored in memory. In step 1016, the calculated cardiac parameters and / or cardiac function parameters are displayed.

[0101] In step 1018, recommended treatment is determined based on the calculated cardiac parameters and cardiac function parameters. The recommended treatment is based on the calculated cardiac parameters and cardiac function parameters. In some embodiments, the recommended treatment is based on a comparison of the calculated cardiac parameters and / or cardiac function parameters with thresholds. In some embodiments, the recommended treatment is based on a comparison of changes in the calculated cardiac parameters and / or cardiac function parameters over a period of time. In some embodiments, the recommended treatment is determined by accessing a lookup table and extracting doses corresponding to the current values ​​of the calculated cardiac parameters and cardiac function parameters.

[0102] For example, to determine whether a pharmaceutical intervention is justified or beneficial, a combination of calculated cardiac parameters, such as spontaneous cardiac output, LVEDP, and cardiac output, may be analyzed by an algorithm and compared to thresholds. The algorithm may determine that administration of an inotropic agent is justified; and further analysis, such as examining a dose lookup table, may enable the algorithm to provide recommendations to clinical healthcare professionals for the administration of an inotropic agent and for specific doses or dose settings to be used in that treatment.

[0103] By monitoring and analyzing additional cardiac parameters, the algorithm can also provide clinical healthcare professionals with information and recommendations for adjusting the patient's fluid intake or administering diuretics. By measuring and determining cardiac parameters such as spontaneous output, LVEDP, and aortic pulse pressure variability, the algorithm can identify the patient's condition and whether the patient is within the optimal fluid window, and can also assess and report on the patient's fluid responsiveness.

[0104] In step 1020, the recommended dose associated with the recommended treatment is determined. The recommended dose is based on the calculated cardiac parameters and cardiac function parameters. In some embodiments, the recommended dose is based on a comparison of the calculated cardiac parameters and / or cardiac function parameters with thresholds. In some embodiments, the recommended dose is based on a comparison of changes in the calculated cardiac parameters and / or cardiac function parameters over a period of time. In some embodiments, the recommended dose is determined by accessing a lookup table for the recommended treatment and extracting the dose corresponding to the current values ​​of the calculated cardiac parameters and cardiac function parameters.

[0105] In step 1022, the recommended treatment and recommended dose are generated and displayed for display. The recommended treatment and recommended dose may be displayed within the user interface shown in Figure 3. In some embodiments, the recommended treatment and recommended dose are displayed on the main screen. In some embodiments, the recommended treatment and recommended dose are displayed as a pop-up notification or warning. As in process 900, the recommended treatment and recommended dose may be displayed to the clinical professional along with a warning to prompt the clinical professional to follow a specific protocol or to monitor or check other cardiac function parameters before administering treatment.

[0106] Figure 11 shows process 1100 for alerting the user to anticipated cardiac adverse events based on measured and calculated cardiac parameters. Process 1100 includes steps 1102–1120, which are substantially similar to steps 702–720 in Figure 7. These steps are briefly listed here, but those skilled in the art will understand that the substitutes and additional details included in the descriptions of the corresponding steps in Figure 7 also apply to steps 1102–1120 in Figure 11.

[0107] In step 1102, the motor of the cardiac pump is activated. In step 1104, the aortic pressure is measured. In step 1106, the current delivered to the motor is measured, and the motor speed is also measured. In step 1108, the differential pressure across the blood pump cannula is determined based on the measured motor current and measured motor speed. In step 1110, cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure. The calculated cardiac parameters may be LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. In step 1112, the calculated cardiac parameters are recorded in memory. In step 1114, cardiac function parameters are determined based on the calculated cardiac parameters. Cardiac function parameters may be any of the following: cardiac output, cardiac power, spontaneous cardiac output, spontaneous cardiac power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance. In some embodiments, cardiac function parameters are also stored in memory. In step 1116, the calculated cardiac parameters and / or cardiac function parameters are generated for display and displayed to the user. The calculated cardiac parameters and / or cardiac function parameters may be generated for display as instantaneous values, maximum and minimum values ​​over a period of time, and / or historical trends over time. The calculated cardiac parameters and / or cardiac function parameters are then displayed to the user.

[0108] In step 1118, the calculated cardiac parameters and / or cardiac function parameters are compared to a threshold. In some embodiments, the set threshold is a system value set within the controller. In some embodiments, the set threshold is set by a clinical healthcare professional based on the patient's history and health status. In some embodiments, the set threshold is a prior value of a cardiac metric, such as a prior value measured or calculated a predetermined time earlier. In step 1120, it is determined whether the calculated cardiac parameters and / or cardiac function parameters meet the threshold. The set threshold is set such that the cardiac parameter or cardiac function parameter that meets the threshold serves as an early warning signal or potential indicator that a cardiac event or ischemic event is progressing.

[0109] Many adverse events are predictable based on the determination of cardiac parameters and the comparison of cardiac parameters or their temporal trends with thresholds. Furthermore, displaying these additional cardiac parameters in real time for healthcare professionals, and including historical data, allows physicians to better understand the patient's health status and predict and address potential adverse events. For example, additional ischemic events, conduction abnormalities, or bleeding and hemolysis may be detected and addressed based on cardiac parameters calculated and displayed according to the algorithms described herein. Based on these predictions of adverse events, physicians may make clinical decisions, such as optimizing support to maximize spontaneous recovery and balancing left and right ventricular support.

[0110] In step 1122, an alarm is triggered regarding cardiac parameters and / or cardiac function parameters. The alarm may be an audible alarm or may be displayed within the user interface shown in Figure 3. In some embodiments, the alarm may be sent to a clinical healthcare professional as a page, text, or email via a Wi-Fi network, Bluetooth signal, or cellular signal. In some embodiments, the warning is displayed on the main screen. In some embodiments, the warning is displayed as a pop-up message. In some embodiments, the warning can be turned off or muted by the clinical healthcare professional.

[0111] Figure 12 shows process 1200 for balancing right and left ventricular blood pump devices during biventricular support based on measured and calculated cardiac parameters. When both left and right ventricular devices provide simultaneous cardiac support, balancing right and left ventricular output to maintain adequate intrapulmonary pressure and limit the risk of pulmonary edema can be challenging. Measuring spontaneous cardiac output and total output, along with pulmonary artery pressure and left ventricular diastolic pressure, allows clinicians to better balance right and left ventricular support.

[0112] In step 1202, the first motor of the first blood pump is activated. This may be, for example, a right-heart device placed in the right ventricle and pulmonary artery of the heart. In step 1204, the second motor of the second blood pump is activated. This may be, for example, a left-heart device placed in the left ventricle and aorta of the heart. The first and second motors are activated simultaneously to provide support to both sides of the heart. In step 1206, the pressure at the pump outlet is measured. For the second pump, which is a left-heart device, this is the aortic pressure. For the first pump, which is a right-heart device, this is the pulmonary artery pressure. The aortic pressure may be measured by a pressure sensor connected to the heart pump, by a separate catheter, by a non-invasive pressure sensor, or by any other suitable sensor. The pressure sensor may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometry sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor. In some embodiments, ventricular pressure is measured as an addition to or alternative to the measurement of aortic pressure.

[0113] In step 1208, the first motor current and first motor speed of the first blood pump are measured, and the second motor current and second motor speed of the second blood pump are measured. In step 1210, the first differential pressure across the first cannula of the first blood pump is determined based on the measured first motor current and the measured first motor speed, and the second differential pressure across the second cannula of the second blood pump is determined based on the measured second motor current and the measured second motor speed. The first and second differential pressures may be determined by using a lookup table, or by accessing a function that describes the measured motor current, the measured motor speed, and optionally other parameters.

[0114] In step 1212, the first cardiac parameter is calculated based on the first differential pressure across the first cannula of the first blood pump and the first pump outlet pressure, and the second cardiac parameter is calculated based on the second differential pressure across the second cannula of the second blood pump and the second pump outlet pressure. The first cardiac parameter derived from the right heart device may be any of the following: right ventricular pressure, right ventricular end-diastolic pressure, pulmonary artery pressure, right arterial pressure, central venous pressure, or blood pump flow rate. The second cardiac parameter derived from the left heart device may be any of the following: LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, heart rate, or right arterial pressure. These cardiac parameters may each be used by a clinical healthcare professional as a measure of various aspects of cardiac health and function, and to better balance the right and left heart devices to provide balanced cardiac support.

[0115] Furthermore, the temporal trends of each cardiac parameter may be used by clinical healthcare professionals to determine whether spontaneous cardiac output is improving or decreasing, and clinical decision-making regarding the support provided by the blood pump and drug therapy may be based on these trends. In some embodiments, two or more cardiac parameters are calculated based on the differential pressure across the blood pump cannula and the aortic pressure.

[0116] In step 1214, cardiac function parameters are determined based on the calculated primary cardiac parameters and / or secondary cardiac parameters. The cardiac function parameters may be cardiac output, cardiac power, spontaneous output, spontaneous power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance, or any similar parameter associated with right heart support. These cardiac function parameters may be derived from the calculated cardiac parameters and other available measurable parameters. The cardiac function parameters provide clinicians with additional information about cardiac function and the balance of support provided by the primary and secondary blood pumps. In some embodiments, the cardiac function parameters are also recorded in memory to provide historical data and trends in cardiac function parameters over time. In some embodiments, two or more cardiac function parameters are determined.

[0117] In step 1216, recommended changes to the level of support provided by the primary and / or secondary blood pumps are determined. These recommended changes to the level of support may be accessed from a lookup table stored in memory, or they may be calculated based on current or historical values ​​of cardiac parameters and cardiac function parameters. The recommended changes to the level of support may include prompts to increase or decrease pump support, and / or recommendations for the amount of change to be made to pump support.

[0118] In step 1218, recommended changes to the level of support provided by the first and / or second blood pumps are generated and displayed for display. The recommended changes to the level of support provided by the first and / or second blood pumps may be displayed within the user interface of Figure 3. In some embodiments, the recommended changes to the level of support provided by the first and / or second blood pumps are displayed on the main screen. In some embodiments, the recommended changes to the level of support provided by the first and / or second blood pumps are displayed as a pop-up or warning. The recommended changes to the level of support provided by the first and / or second blood pumps may be displayed to a clinical healthcare professional along with additional information about the first and second blood pumps, and with a prompt urging them to follow the protocol and perform further checks before changing the level of support provided by adjusting the motor speed of the first or second blood pump. In some embodiments, the controller may determine an appropriate change in motor speed for one or both of the first and second blood pumps, and may also determine whether the first and second blood pumps currently providing assistance are the optimal blood pumps to operate at the recommended motor speed to provide the recommended level of assistance.

[0119] By using data collected by one or more blood pumps and blood pump systems to calculate clinically relevant cardiac parameters and cardiac function parameters, and by displaying these parameters in real time for clinical professionals, important information about cardiac health and function that can be used to make clinical decisions about support is provided to clinical professionals. Furthermore, algorithms within the blood pump controller or console that assist clinical professionals in determining potential challenges and provide recommendations to improve cardiac function give them the ability to detect challenges earlier and respond to problems more quickly than if this important information were not available.

[0120] Figure 13 shows a block diagram 1300 of a process for automatically correcting the level of assistance provided by a blood pump. In step 1302, a blood pump placed in the heart is activated to provide a certain level of cardiac assistance to the heart. The blood pump has a cannula and a motor that operates at a certain motor speed and draws a certain variable current to provide assistance to the heart. In step 1304, a controller connected to the blood pump measures the aortic pressure in the heart. In step 1306, the controller measures the motor current and motor speed. In step 1308, the controller determines the pressure gradient across the cannula, associated with the motor current and motor speed.

[0121] In step 1310, the processor calculates cardiac parameters based on the aortic pressure and the pressure gradient across the cannula, which is associated with the motor current and motor speed. In step 1312, the calculated cardiac parameters are stored in memory. In step 1314, cardiac function parameters are determined based on the calculated cardiac parameters. In some embodiments, cardiac function parameters are also stored in memory. In step 1316, a recommended change to the level of cardiac assistance provided by the blood pump is determined based on at least one of the calculated cardiac parameters and cardiac function parameters. In step 1318, the recommended change to the level of cardiac assistance is generated for display.

[0122] In some embodiments, two or more cardiac parameters are calculated from the aortic pressure and the pressure gradient across the cannula. Any number of cardiac parameters may be calculated, for example, including LVEDP, LVP, aortic pulse pressure, mean aortic pressure, pump flow rate, pressure gradient, or heart rate. In some embodiments, these cardiac parameters are also generated for display as maximum or minimum values, average values, instantaneous values, historical trends, or waveforms. In some embodiments, two or more cardiac function parameters are determined from the cardiac parameters. For example, the cardiac function parameters may be cardiac output, cardiac power, spontaneous cardiac output, spontaneous power, myocardial contractility, myocardial flaccidity, fluid responsiveness, volume state, cardiac load reduction index, cardiac recovery index, left ventricular diastolic function, left ventricular diastolic elastance, left ventricular systolic elastance, stroke volume, heart rate variability, stroke volume variability, pulse pressure variability, aortic compliance, vascular compliance, or vascular resistance.

[0123] In some embodiments, the calculated cardiac parameter is LVEDP, and the cardiac function parameter is heart rate output. By calculating LVEDP and heart rate output, recommendations for adjusting cardiac assistance may be determined based on historical data. Based on the patient's cardiac health status indicated by LCEDP and heart rate output, recommendations to increase the motor speed (to increase cardiac assistance by the blood pump for patients with deteriorating health) or decrease the motor speed (to wean patients off the blood pump for patients with improving health) may be determined, generated for display, and displayed to healthcare professionals.

[0124] Such recommendations may be determined by comparing current LVEDP and / or heart rate output values ​​with precedent values ​​or set thresholds. Based on this comparison, a lookup table stored in memory may provide recommendations; the recommendations may include the determined indicators of the recommended changes in the support level and a list of steps to achieve the recommended changes. Alternatively, in some embodiments, the recommended changes in the cardiac support level may be automated by the controller.

[0125] Various combinations of cardiac metrics and parameters can be useful in determining a patient's cardiac health and aspects of cardiac and blood pump functionality. These parameter values, along with recommendations and warnings generated by algorithms based on current thresholds or historical information related to the patient's health, enable healthcare professionals to make informed decisions regarding the adjustment of support, as well as many other medical decisions as described above (see Figures 4-12).

[0126] Figure 14 shows a block diagram of an exemplary blood pump system 1400 for implementing any of the methods described above with respect to Figures 4-13. The cardiac pump system 1400 may operate within the heart, partially within the heart, outside the heart, partially outside the heart, partially outside the vascular system, or in any other preferred location within the patient's vascular system. The blood pump system 1400 includes a console 1401 and a blood pump 1402. The console 1401 includes a drive unit 1404, memory 1406, processor 1408, circuitry 1403, and a display 1410.

[0127] The blood pump system 1400 may be used with any suitable blood pump device to provide cardiac support to the right or left side of the heart, for example, blood pump 1402 may be blood pump 100 shown in Figure 1. Blood pump 1402 includes a motor 1405 and a sensor 1407, as well as other components of blood pump 100 in Figure 1, which are not shown in the figure. In some embodiments, the blood pump system 1400 may be used with two blood pumps to provide cardiac support to the left and right sides of the heart simultaneously.

[0128] The blood pump 1402 is connected to the drive unit 1404 by a circuit 1403. All or part of the circuit 1403 may be located within a console 1401 separate from / away from the blood pump 1402. In some embodiments, the circuit 1403 is located inside the blood pump 1402. The circuit 1403 and blood pump 1402 are not shown to uniform scale. The drive unit 1404 supplies current to the motor 1405 of the heart pump 1402 via the circuit 1403. The current supplied by the drive unit 1404 to the motor 1405 of the heart pump 1402 on wire 1426 is measured by a current sensor 1409 located within or connected to the drive unit 1404.

[0129] An indwelling signal or aortic pressure is measured at a pressure sensor 1407 located on the blood pump 1402. The pressure detected by the pressure sensor 1307 is received by the drive unit 1404 via the circuit 1403; and may be passed to the processor 1408 along with the current supplied to the motor 1405. In some embodiments, the aortic pressure may be measured by the pressure sensor 1407 connected to the blood pump 1402, by a separate catheter, by a non-invasive pressure sensor, or by any other suitable sensor. The pressure sensor 1407 may be a fluid-filled tube, a differential pressure sensor, a hydraulic pressure sensor, a piezoelectric strain gauge, an optical interferometry sensor or other optical sensor, a MEMS piezoelectric sensor, or any other suitable sensor.

[0130] The processor 1408 includes software and / or hardware to receive motor current and pressure measurement results from the drive unit 1404 and to use these values ​​to determine several additional cardiac parameters and cardiac function parameters. For example, the processor includes software that uses the method described with respect to Figures 2A-2E to calculate LVP and LVEDP from the motor current of the blood pump 1402 and aortic pressure information received from the pressure sensor 1407. Furthermore, the processor 1408 can store the received measurement results, parameters, and values ​​in memory 1406 and can access the values ​​and parameters stored in memory to generate them for display on the display 1410.

[0131] The processor 1408 further includes an algorithm that performs the steps described with respect to Figures 4-13 in order to accept or request current and aortic pressure values ​​from the drive unit 1404, and to determine cardiac parameters and cardiac function parameters that are indicators of the health or function of the heart from these values. These values ​​may also be generated for user display and may be displayed on the display 1410.

[0132] The processor 1408 can access functions and lookup tables stored in memory 1406 to make decisions regarding calculated cardiac parameters and cardiac function parameters, and to use those decisions to make recommendations regarding the treatment and support to be provided to the patient's heart. The processor 1408 can generate recommendations and display these recommendations on display 1410.

[0133] The display 1410 may be substantially the same as the user interface 300 in Figure 3. The display provides clinically relevant, calculated cardiac parameters and cardiac function parameters to the clinical healthcare professional so that they can make procedural decisions using real-time data. Furthermore, the display 1410 enables the processor 1408 to display recommendations to the clinical healthcare professional so that they can more quickly detect and respond to life-threatening cardiac problems. The processor 1408 on the console 1401 provides the clinical healthcare professional with additional information using the blood pump 1402 and accessible measurements to help them provide more efficient and effective cardiac treatment to patients.

[0134] The foregoing is merely illustrative of the principles of this disclosure, and the device may be implemented in ways other than those described herein, which are presented for illustrative purposes only, not limitation. It should be understood that, although the device disclosed herein is shown for use in percutaneous insertion of a cardiac pump, it may be applicable to devices for other uses.

[0135] Those skilled in the art will be able to conceive of variations and modifications after reviewing this disclosure. The features of this disclosure may be implemented in any combination and subcombinations (including multiple dependent combinations and subcombinations) with one or more other features described herein. The various features described or illustrated above, including their components, may be combined or integrated into other systems. Furthermore, certain features may be omitted or not implemented at all.

[0136] In general, the subjects and functional modes described herein may be implemented in digital electronic circuits, or in software, firmware, or hardware, including the structures disclosed herein and their structural equivalents, or in one or more combinations thereof. The subjects described herein may be implemented as one or more computer program products, i.e., as one or more modules of computer program instructions encoded on a computer-readable medium for execution by a data processing device or for controlling calculations of a data processing device. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a memory device, a material composition that affects machine-readable propagating signals, or one or more combinations thereof. The term “data processing apparatus” encompasses all devices and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. The device may include, in addition to hardware, code that creates an execution environment for the target computer program, such as code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or one or more of these. The propagating signal is an artificially generated signal, such as a mechanically generated electrical signal, optical signal, or electromagnetic signal, that is produced to encode information for transmission to a suitable receiving device.

[0137] Computer programs (also known as programs, software, software applications, scripts, or code) may be written in any form of programming language, including languages ​​that are compiled or translated, and may be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment. Computer programs do not necessarily correspond to files in a file system. A program may be stored in part of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in a series of interconnected files (e.g., one or more modules, subprograms, or files that store parts of code). Computer programs may be deployed for execution on one computer or on multiple computers located in one place or distributed across multiple locations and interconnected by a network.

[0138] The processes and logic flows described herein may be performed by one or more programmable processors that execute one or more computer programs, for the purpose of performing operations on input data and generating outputs. The processes and logic flows may also be performed by dedicated logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits), and the device may be implemented as a dedicated logic circuit.

[0139] Processors suitable for executing computer programs include, for example, general-purpose and dedicated microprocessors, as well as one or more arbitrary processors in any type of digital computer. Generally, a processor receives instructions and data from read-only memory, random-access memory, or both. Essential elements of a computer are a processor for executing instructions, and one or more memory devices for storing instructions and data. Generally, a computer also includes one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks; or is operationally coupled to such mass storage devices to receive data from them, transfer data to them, or both. However, a computer does not necessarily have to have such devices.

[0140] Examples of changes, substitutions, and modifications are verifiable to those skilled in the art and can be made without departing from the scope of the information disclosed herein. All references herein are incorporated by reference in their entirety and constitute part of this application.

Claims

1. A blood pump configured to be placed inside the heart, Cannula and, A motor configured to operate at a certain motor speed and draw a variable motor current in order to provide a certain level of cardiac support to the aforementioned heart, A blood pump equipped with, It is a controller, Memory and User interface and Receive aortic pressure measurement, The measured value of the variable motor current is received, Determine the pressure gradient across the cannula, which is associated with the variable motor current. Cardiac parameters are calculated from the aortic pressure and the pressure gradient across the cannula. The calculated cardiac parameters are recorded in memory. Based on the calculated cardiac parameters, cardiac function parameters are determined. The calculated cardiac parameters or cardiac function parameters are generated for display on the user interface. Based on the calculated cardiac parameters and cardiac function parameters, a recommended change to the motor speed is determined. The recommended changes to the motor speed are generated for display on the user interface. Receiving user input instructions in response to the display of the recommended change to the motor speed, The motor speed is adjusted according to the user input. A processor configured as follows, A controller equipped with, A system equipped with the ability to provide cardiac support to the heart.

2. The system according to claim 1, wherein adjusting the motor speed in accordance with the user input includes increasing the motor speed in order to increase blood flow from the heart.

3. The system according to claim 1, wherein adjusting the motor speed in accordance with the user input includes reducing the motor speed to disengage the heart from cardiac support.

4. The aforementioned controller The recommended change to the motor speed is compared with a threshold stored in the memory. If the recommended change to the motor speed satisfies the threshold, a recommendation to use different blood pumps with different flow rates is generated for display on the user interface. The system according to claim 1, further configured as follows.

5. The system according to any one of claims 1 to 4, wherein the calculated cardiac parameters include ventricular pressure, ventricular end-diastolic pressure, differential pressure across the cannula, blood pump flow rate, spontaneous cardiac output, total cardiac output, spontaneous cardiac output, or total cardiac output.

6. The system according to any one of claims 1 to 4, wherein the cardiac function parameters include cardiac contractility, cardiac relaxation, fluid response, cardiac output measurement, ventricular diastolic dysfunction measurement, ventricular systolic elastance, or ventricular diastolic elastance.

7. A blood pump configured to be placed inside the heart, Cannula and, A motor configured to operate at a certain motor speed and draw a variable motor current in order to provide a certain level of cardiac support to the aforementioned heart, A blood pump equipped with, It is a controller, Receive aortic pressure measurement, The measured value of the variable motor current is received, Determine the pressure gradient across the cannula, which is associated with the variable motor current. Cardiac parameters are calculated from the aortic pressure and the pressure gradient across the cannula. The calculated cardiac parameters are recorded in memory. Based on the calculated cardiac parameters, cardiac function parameters are determined. The calculated cardiac parameters or cardiac function parameters are generated for display on the user interface. Based on the calculated cardiac parameters and cardiac function parameters, a recommended treatment, including the administration of therapeutic substances or drugs, is determined. The recommended treatment is generated for display on the user interface. A controller configured as follows, A system equipped with the ability to provide cardiac support to the heart.

8. The system according to claim 7, wherein the controller is further configured to generate a recommended dose of the recommended treatment for display on the user interface.

9. The system according to claim 7, wherein the recommended treatment includes the administration of the therapeutic substance, and the therapeutic substance is a cardiac stimulant.

10. The system according to claim 7, wherein the recommended treatment includes the administration of the therapeutic substance, the therapeutic substance being a diuretic or an intravenous fluid.

11. The system according to any one of claims 7 to 10, wherein the calculated cardiac parameters include ventricular pressure, ventricular end-diastolic pressure, differential pressure across the cannula, blood pump flow rate, spontaneous cardiac output, total cardiac output, spontaneous cardiac output, or total cardiac output.

12. The system according to any one of claims 7 to 10, wherein the cardiac function parameters include cardiac contractility, cardiac relaxation, fluid response, cardiac output measurement, ventricular diastolic dysfunction measurement, ventricular systolic elastance, or ventricular diastolic elastance.

13. A first blood pump configured to be located on the left side of the heart, First cannula and, A first motor that is capable of operating at the first motor speed and is configured to draw in the first variable motor current, A first blood pump equipped with, A second blood pump configured to be positioned on the right side of the heart, Second cannula and, A second motor that is capable of operating at the second motor speed and is configured to draw in the second variable motor current, A second blood pump, equipped with, It is a controller, Receive aortic pressure measurement, The measured values ​​of the first variable motor current and the second variable motor current are received. Determine the first pressure gradient across the first cannula, which is associated with the first variable motor current, and the second pressure gradient across the second cannula, which is associated with the second variable motor current. The first cardiac parameter is calculated from the aortic pressure and the first pressure gradient spanning the first cannula, and the second cardiac parameter is calculated from the aortic pressure and the second pressure gradient spanning the second cannula. Based on the first cardiac parameter and the second cardiac parameter calculated above, the cardiac function parameters are determined. Based on the calculated first cardiac parameter, the calculated second cardiac parameter, and the cardiac function parameter, a recommended change to the level of support provided by either the first blood pump or the second blood pump is determined. Generate for display on the user interface the recommended changes to the level of support provided by either the first blood pump or the second blood pump. A controller configured as follows, A system equipped with the ability to provide cardiac support to the heart.

14. A blood pump configured to be placed inside the heart, Cannula and, A motor configured to operate at a certain motor speed and draw a variable motor current in order to provide a certain level of cardiac support to the aforementioned heart, A blood pump equipped with, It is a controller, Receive aortic pressure measurement, The measured value of the variable motor current is received, Determine the pressure gradient across the cannula, which is associated with the variable motor current. Cardiac parameters are calculated from the aortic pressure and the pressure gradient across the cannula. The calculated cardiac parameters are recorded in memory. Based on the calculated cardiac parameters, cardiac function parameters are determined. The calculated cardiac parameters or cardiac function parameters are generated for display on the user interface. The calculated cardiac parameters or cardiac function parameters are compared with the first threshold. If the cardiac parameter or cardiac function parameter satisfies the first threshold, an alarm is triggered. A controller configured as follows, A system equipped with the ability to provide cardiac support to the heart.

15. The aforementioned controller The difference between the measured and calculated cardiac parameters and the previously recorded cardiac parameters accessed from the memory, or The difference between the measured cardiac function parameters and the previously recorded cardiac function parameters from the memory, We decided, The difference is compared with the second threshold, If the difference satisfies the second threshold, an alarm is triggered. The system according to claim 14, further configured as follows.

16. Triggering the alarm includes generating a warning notification for display on the user interface, and the controller, Upon receiving user input instructions in response to the display of the aforementioned warning notification, The motor speed is adjusted according to the user input. The system according to claim 14, further configured as follows.

17. The system according to any one of claims 14 to 16, wherein the calculated cardiac parameters include ventricular pressure, ventricular end-diastolic pressure, differential pressure across the cannula, blood pump flow rate, spontaneous cardiac output, total cardiac output, spontaneous cardiac output, or total cardiac output.

18. The system according to any one of claims 14 to 16, wherein the cardiac function parameters include cardiac contractility, cardiac relaxation, fluid response, cardiac output measurement, ventricular diastolic dysfunction measurement, ventricular systolic elastance, or ventricular diastolic elastance.

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