Use of cardiac assist device to improve kidney function

Abstract

To provide systems and methods for improving a kidney function.SOLUTION: A first mechanical circulatory support system (MCS) is introduced in a patient's heart, and a second mechanical circulatory support system is introduced in a patient's inferior vena cava or renal vein. The second mechanical circulatory support system is operated while the first mechanical circulatory support system is operating. A renal parameter is monitored during operation of the first and second mechanical circulatory support systems. The combined operation of the first and second mechanical circulatory support systems results in a change in a renal parameter, e.g., a pressure drop in the renal vein, indicating an improvement in a kidney function. Once it is determined that the renal parameter is below a target threshold, the operation of the second mechanical circulatory support device is stopped.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. No. 16 / 406,896, "Use of Cardiac Assist Device to Improve Kidney Function," filed May 8, 2019, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] background The kidneys play a central role in controlling arterial fluid pressure in the body. They regulate renal output by altering the excretion of water (diuresis) and also by altering the excretion of salt (natriuresis). This regulation is reflected in the renal output curve (Figure 1), in which urine output varies with arterial pressure. Under normal conditions, the kidneys themselves can autoregulate by increasing or decreasing urine output and renal blood flow in response to increases or decreases in blood pressure or flow rate or changes in salt concentration. However, injury or other changes in renal function can impair autoregulation. For example, impaired renal function can increase the levels of water and salt in the circulation, increasing arterial pressure. Conversely, heart failure or coronary disease can dramatically reduce cardiac output, which reduces blood flow to the renal arteries and impairs urine output.

[0003] Many people suffer from acute kidney disease, renal failure, and other kidney disorders. Some kidney disorders are thought to be caused or exacerbated by contrast agents, dyes, and other media used during CT scans, angiograms, and other examination procedures. These conditions include, for example, contrast-induced nephropathy and nephrogenic systemic fibrosis, or general nephrotoxicity. Patients with diabetes, heart disease, blood disease, and other vascular diseases may be more susceptible to such disorders. One frequent indicator of kidney disorder is a decrease in glomerular filtration rate (GFR) and renal output, accompanied by an acute condition known as oliguria (acutely reduced urine output).

[0004] Particularly during surgery, patients with weakened cardiac function and / or pre-existing renal conditions may need to undergo cardiac bypass. Their hearts release stressors throughout the body as a result of the stress of surgery. The type and amount of stressors released by the heart varies depending on the length and nature of the surgery (e.g., CABG, valve replacement, valve repair, etc.). Patients may be monitored for renal output as an indicator of recovery either during or immediately after surgery. For example, creatinine rise or filtration rate fall may be monitored to gauge the patient's recovery. Current systems, such as ECMO, that provide flat line pressure do not improve renal function and may actually damage the kidneys by placing them under high pressure. High-risk cardiac patients (e.g., STEMI, CS, PCI) often also develop acute renal disease, renal failure, or renal injury, and monitoring renal output as an indicator of recovery is particularly important for these patients.

[0005] It would be desirable to provide improved methods and systems that can improve kidney functionality, especially in cases of vascular disease. It would be desirable to provide a system or method that can provide one or more of the following: improved renal output, reduced nephrotoxicity of various agents, and controlled renal autoregulation. It would be desirable to provide a system or method that can increase flow into the kidney to increase urine output and increase the disposal of undesirable stressors out of the body. It would also be desirable to provide a system or method that can monitor renal parameters to determine when flow into the kidney is sufficient such that increased flow into the kidney is no longer necessary. Summary of the Invention

[0006] overview Methods and systems are provided herein to address one or more of the aforementioned problems. Renal output can be increased by increasing blood flow through the kidney. Blood flow through the kidney can be regulated by unloading the heart and maintaining or increasing arterial pressure upstream of the kidney; maintaining or decreasing venous pressure downstream of the kidney; or a combination of both, the selection being made to maintain or increase the pressure gradient across the kidney. At least one benefit of unloading the heart and increasing arterial pressure upstream of the kidney is to increase the release of one or more humoral factors that act on renal receptors (located at or near the renal artery, or on or near either the glomerulus or nephron components) or on other receptors in the vascular tissue. Increasing these humoral factors that bind to the kidney advantageously increases the kidney's ability to process undesirable stressors out of the body. Similarly, at least one benefit of reducing venous pressure downstream of the kidney is to increase blood flow (including humoral factors) through the kidney, thereby increasing renal output. The methods and systems provided herein also address renal monitoring by monitoring renal parameters to determine whether the second blood pump can be turned off. For example, at least one advantage of monitoring the pressure gradient across the kidney or the venous pressure drop in the renal vein is that a decision can be made to turn off the second blood pump once the patient has sufficiently regained renal function. In one embodiment, the first and second blood pumps may be one of the blood pumps known as Impella® pumps, and the first blood pump may be applied to the left or right side (or both) of the heart, such as by using any of the techniques identified in Appendix A.

[0007] In some embodiments, a method for regulating renal function in a patient is provided. The steps of the method include inserting a first mechanical assist device, such as a first blood pump, into the patient's heart and operating the first blood pump to increase aortic pressure. For example, the blood pump may be introduced into the patient's left or right heart. In a left ventricular application, the pump inlet is positioned in the left ventricle and the pump outlet is in the aorta. Alternatively, the blood pump may be inserted into the left atrium such that the pump inlet is in the left atrium and the pump outlet is in the left ventricle. Alternatively, the blood pump may be inserted in any position that unloads the heart and maintains or increases cardiac output. The method also includes inserting a second mechanical assist device, such as a second blood pump, into the patient's inferior vena cava and operating the second blood pump while the first blood pump is operating. For example, the second blood pump is placed near or in the inferior vena cava, in the inlet of the inferior vena cava, or in the renal vein. The inlet of the second blood pump may be located within the junction between the patient's renal vein and the inferior vena cava. In another embodiment, the second blood pump is configured to partially occlude the inferior vena cava such that operation of the second blood pump creates a pressure drop upstream of the inlet of the second blood pump (between the pump and the kidney, including within the renal vein). In these embodiments, operation of the first and second blood pumps achieves a target pressure drop at a location within the patient's renal vein or inferior vena cava. In this manner, the first and second blood pumps may be operated simultaneously - the first pump on the arterial side of the kidney increases pressure upstream of the kidney, while the second pump located distal (downstream) of the kidney unloads the kidney, thereby reducing pressure within the renal vein. In other adaptations, one of the blood pumps is operated continuously and the other of the blood pumps is selectively turned on and off to achieve the target pressure drop. The first and second blood pumps may also be operated at different speeds and for different periods of time. For example, a first blood pump may be operated at about 40,000 rpm for up to 6 hours, and a second blood pump may be operated at 30,000 rpm for about 3 hours.Alternatively, both the first and second blood pumps may be run at similar speeds for the same period of time.

[0008] At least one advantage of using the first blood pump is that it not only unloads the left or right ventricle (or both) of the heart, or the left or right atrium (or both), thereby improving blood circulation through the renal artery, but also stimulates the release of one or more humoral factors acting on renal receptors (either at or near the renal artery, or at or near either the glomerulus or nephron components) or other receptors in the vascular tissue. Such stimulation increases renal output, helping to operate and maintain renal autoregulation, and also helping to protect the kidney from toxicity and damage. The placement and operation of the first blood pump may be used to unload the left ventricle, thereby reducing left ventricular pressure (and left atrial pressure) and left ventricular volume, or to unload the right ventricle, thereby reducing right ventricular pressure (and right atrial pressure) and right atrial volume, or both.

[0009] At least one benefit of unloading the ventricle by pumping blood from the ventricle into the arteries to carry blood away from the heart (either the aorta or pulmonary artery) is an overall increase in arterial pressure, which increases pulsatility in the vasculature and increases the flow of blood into the renal arteries and kidneys, thereby increasing the glomerular filtration rate. Another benefit of running a first pump, such as an Impella® pump, in the patient's heart is to increase diastolic pressure without constantly maintaining the kidneys at high pressure - which receives a significant amount of blood flow. Yet another benefit of unloading the heart, such as with an Impella® pump, is to upregulate the production of one or more humoral factors in cardiac tissue (or arterial tissue) and the release of one or more of such factors into the circulation. The majority of humoral factors are produced in the left atrium of the heart - unloading the heart decompresses the left atrium, boosting humoral factor production (e.g., ANP production). Humoral factors that flow to the kidney and / or other organ receptors activate the kidney or other organ receptors to stimulate increased function of the organ. Humoral factors that flow to the kidney activate the renal receptors to stimulate increased urine output from the kidney. For example, released humoral factors bind to renal receptors or receptors of other organs. When humoral factors reach the renal artery (and the nephrons of the kidney), they bind to one or more renal receptors, thereby activating afferent and / or efferent arterioles directly facing mesangial cells in the glomerulus, thereby increasing or decreasing renal blood flow. Increasing renal blood flow increases or decreases, or maintains, the glomerular filtration rate, even if the renal perfusion pressure is changed. Additionally or alternatively, humoral factors may activate the tubule walls to excrete and / or absorb or reabsorb glucose, salt, or other electrolytes in the urine, with water from the surrounding vasculature and tissues passively following changes in urinary electrolyte levels, which causes corresponding regulation (increase / reduction / maintenance of urine output and content) even in the face of changes in renal perfusion pressure and changes in blood electrolytes, glucose, and trace elements.Receptors in the kidney that are affected by this effect include atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), NT-proBNP, catecholamine receptors, adenosine receptors, angiotensin receptors (AT1, AT2), prostaglandin receptors, alpha-ketoglutarate receptors, glutamate receptors, etc. For example, renal receptors are located within the nephron, tubule, medulla, or cortex of the kidney.

[0010] In some embodiments, operating a first blood pump in the heart maintains or increases arterial pressure in the renal artery. In other embodiments, operating a second blood pump in the inferior vena cava maintains or decreases renal venous pressure. For example, in one embodiment, the first blood pump is operated to increase arterial pressure while the second blood pump is operated to decrease renal venous pressure. In another embodiment, the first blood pump is operated to maintain arterial pressure while the second blood pump is operated to decrease renal venous pressure. In yet another embodiment, the first blood pump is operated to increase arterial pressure while the second blood pump is operated to maintain renal venous pressure.

[0011] In some embodiments, the target pressure drop at a location within the patient's renal vein or inferior vena cava increases blood flow through the kidney and increases renal output. For example, the target pressure drop is between about 4 mmHg and about 8 mmHg. In another example, the target pressure drop is between about 5 mmHg and about 7 mmHg. In one example, the target pressure drop is about 6 mmHg. The target pressure drop and the time required to achieve the target pressure drop may vary depending on a particular patient's baseline and the patient's condition. For example, for a particular patient, the maximum achievable pressure drop may be lower than the target pressure drop (e.g., 2 mmHg). In another example, for another patient, the target pressure drop may be achievable but may require a longer period of time for the first and second blood pumps to be run. The target pressure drop and the time required to achieve it may also vary depending on the type of mechanical circulatory support device used - for example, an Impella® pump providing increased diastolic pressure may take less time than an intra-aortic balloon pump or other types of mechanical circulatory systems.

[0012] In some embodiments, the target pressure drop corresponds to a blood pressure drop across the kidney. In one example, the target pressure drop is between 85 mmHg and 95 mmHg. The target pressure drop and the time required to achieve the target pressure drop may vary depending on a particular patient's baseline and condition. The target pressure drop and the time required to achieve it may also vary depending on the type of mechanical circulatory support device used - for example, an Impella® pump providing increased diastolic pressure may take less time than an intra-aortic balloon pump or other types of mechanical circulatory systems.

[0013] In some embodiments, the combined operation of the first and second blood pumps flushes humoral factors to the renal receptors to stimulate increased urine output from the kidney.

[0014] In some embodiments, a first blood pump (e.g., an Impella® pump) includes a pump motor along with a pump housing distal to the pump motor. The pump housing surrounds the rotor, and a cannula extends distally from the pump housing. In some examples, an atraumatic extension extends distally from the cannula. For example, the atraumatic extension is pigtail shaped.

[0015] In some embodiments, the second blood pump includes a pump motor along with a pump housing distal to the pump motor. The pump housing surrounds the rotor and has a cannula extending distally from the pump housing. In some examples, an atraumatic extension extends distally from the cannula. For example, the atraumatic extension is pigtail shaped.

[0016] In some embodiments, the second pump is positioned within the inferior vena cava such that the distal tip of the atraumatic extension extends to a point within the inferior vena cava adjacent the outlet of the renal vein. For example, the distal tip of the atraumatic extension extends between 0 and 2 centimeters of the point where the renal vein joins the inferior vena cava. At least one benefit of having the distal tip extend between 0 and 2 centimeters of the point where the renal vein joins the inferior vena cava is that the inlet of the pump can be stabilized in a desired location adjacent the renal vein.

[0017] In another embodiment, a system for improving renal function includes a first mechanical assist device configured to unload the patient's heart and a second mechanical assist device configured to reduce renal vein pressure. For example, the first mechanical assist device is configured to unload at least one ventricle, at least one atrium, or at least one atrium and ventricle, or both atria and ventricles of the patient. The first and second mechanical assist devices are configured to achieve a target pressure drop in the renal vein when activated simultaneously. In one embodiment, one or both of the mechanical assist devices are blood pumps. In another embodiment, the second mechanical assist device is a balloon pump.

[0018] In some embodiments, the system for improving renal function also includes a controller (e.g., an Automated Impella Controller®) configured to receive arterial pressure from the first mechanical assist device and venous pressure from the second mechanical assist device. The controller determines if the pressure drop in the renal vein is close to a target pressure drop in the renal vein and controls adjusting the operation of at least one of the first mechanical assist device and the second mechanical assist device. In one example, the adjusting the operation helps achieve the target pressure drop in the renal vein. In another example, when the target pressure drop is achieved, the adjusting the operation includes turning off one or both of the mechanical assist devices. In one example, the system includes two controllers (e.g., two Automated Impella Controller®); each controller is associated with one mechanical assist device (e.g., an Impella® pump) and receives data from a respective mechanical assist device.

[0019] In some embodiments, the target pressure drop is configured to increase urine production, for example, the controller is configured to operate one or more of the mechanical assistance devices at respective rates that increase blood flow from the heart and stimulate production of at least one humoral factor that binds to a renal receptor or a receptor of another organ to stimulate and / or regulate urine production and urinary fluid composition from the kidney.

[0020] In some embodiments, the second mechanical assist device comprises a pump motor and a pump housing distal to the pump motor. The pump housing surrounds the rotor and the cannula extends distal to the pump housing. In one example, the second mechanical assist device also comprises an anchoring device configured to anchor the second mechanical assist device to the inferior vena cava during operation of the second mechanical assist device. The anchoring device surrounds a portion of the cannula. The anchoring device may be selectively activated. For example, the anchoring device is a balloon. The balloon may be inflated to partially occlude the inferior vena cava. Alternatively, the anchoring device comprises deployable arms that engage the wall of the inferior vena cava. For example, the anchoring device is a self-expanding cage made of nitinol.

[0021] In some embodiments, the second mechanical assist device is positioned with the inlet positioned at the location where the renal vein connects to the inferior vena cava.

[0022] In some embodiments, each of the first and second mechanical assistance devices includes a pressure sensor for measuring arterial and venous pressure, respectively. In one example, the pressure sensor is integrated into each of the first and second mechanical assistance devices. For example, the first and second mechanical assistance devices are Impella® pumps that include differential pressure sensors or optical pressure sensors. In another example, a separate pressure sensor wire or Swan-Ganz catheter is inserted along each of the first and second mechanical assistance devices. In yet another example, one of the mechanical assistance devices includes an integrated sensor, while the other of the mechanical assistance devices does not include an integrated sensor, but instead is used in combination with a separate pressure sensor wire or Swan-Ganz catheter.

[0023] In some embodiments, when both the first and second mechanical assistance devices are simultaneously activated, the difference between the measured venous pressure and the measured arterial pressure increases. For example, the difference between the measured venous pressure and the measured arterial pressure increases by about 1%. In another embodiment, the difference increases by about 5%.

[0024] In yet another embodiment, a method for improving renal function in a patient includes inserting a first blood pump into the patient's heart and running the first blood pump. The method further includes inserting a second blood pump into the patient's inferior vena cava and running the second blood pump while running the first blood pump. The method also includes monitoring a renal parameter and terminating the operation of the second blood pump when the renal parameter reaches a target level. For example, the target level for the renal parameter is a function of aortic pressure. For example, the renal parameter is a creatinine level or ANP concentration in the blood, or a renal vein pressure. In one embodiment, the target level for the renal vein pressure is less than 15 mmHg. In another embodiment, the renal parameter is a pressure drop across the kidney.

[0025] In some embodiments, the renal parameters are determined by measuring arterial pressure and venous pressure and calculating a pressure difference between the measured arterial pressure and the measured renal venous pressure. In some embodiments, the method for improving renal function in a patient also includes determining that the calculated pressure difference reaches a threshold value.

[0026] In some embodiments, the first blood pump is in communication with a first controller and the second blood pump is in communication with a second controller. For example, the first and second controllers are Automated Impella Controllers® (AICs). In one embodiment, the first controller and the second controller communicate to determine a pressure difference between a measured arterial pressure and a measured renal vein pressure. [Brief description of the drawings]

[0027] These and other objects and advantages will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout. [Figure 1] 1 shows an exemplary renal output curve in which urine output varies according to arterial pressure. [Diagram 2] 1 illustrates an exemplary embodiment of a system disclosed herein. [Diagram 3] 1 illustrates an exemplary method disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Detailed Description In order to allow the system, method and device described herein to be fully understood, certain exemplary embodiments are described. Although the embodiments and features described herein are specifically described for use with an intracardiac heart pump system, it will be understood that all components and other features outlined below may be combined with each other in any suitable manner and may be adapted and applied to other types of medical devices, such as electrophysiology and catheter ablation devices, angioplasty and stent placement devices, angiography catheters, peripherally inserted central catheters, central venous catheters, midline catheters, peripheral catheters, inferior vena cava filters, abdominal aortic aneurysm treatment devices, thrombectomy devices, TAVR delivery systems, cardiac treatment and cardiac assist devices; including balloon pumps, cardiac assist devices implanted using surgical incisions, and any other catheters and devices introduced venously or arterially.

[0029] The systems, methods, and devices described herein allow for improved renal function by maintaining or increasing arterial pressure upstream of the kidney; maintaining or decreasing venous pressure downstream of the kidney; or a combination of both, to achieve increased blood flow through the kidney and thus increased renal output.

[0030] Figure 1 shows an exemplary renal output curve, in which urine output varies according to arterial pressure. For example, as described above, higher arterial pressure increases blood flow to the kidney. Arterial blood carries humoral factors to the kidney, and therefore higher arterial pressure results in a greater amount of humoral factors reaching the kidney and binding to receptors on the kidney, thus increasing renal function and urine output.

[0031] FIG. 2 illustrates an exemplary embodiment of a system 200 configured to provide either similar or higher arterial pressure, similar or lower venous pressure, or a combination of both. A higher arterial pressure (e.g., input to an organ, such as the kidney) results in increased blood flow through the organ. For example, in the case of the kidney, a higher arterial pressure results in increased blood flow through the kidney, and thus increased urine output from the kidney. Similarly, a lower venous pressure (e.g., pressure at the output of an organ, such as the kidney output) results in increased blood flow through the organ. For example, in the case of the kidney, a higher arterial pressure results in increased blood flow through the kidney, and thus increased urine output from the kidney. A combination of a higher arterial pressure (e.g., input to an organ, such as the kidney) and a lower venous pressure (e.g., pressure at the output of an organ, such as the kidney output) results in a similar or greater increase in blood flow through the organ. When the organ is the kidney, a combination of a higher arterial pressure and a lower venous pressure results in increased urine output from the kidney. System 200 includes pump 202 and pump 222. For example, pumps 202 and 222 are Impella® pumps. Alternatively, pumps 202 and 222 are other mechanical circulatory support devices, such as expandable pumps, intra-aortic balloon pumps, or extracorporeal membrane oxygenation (ECMO).

[0032] Pumps 202 and 222 control the input and output to an organ, such as kidney 250 in FIG. 2. For example, kidney 250 may be the left kidney or the right kidney. In one embodiment, the combination of pumps 202 and 222 controls the input and output to both kidneys. For example, turning on one or both blood pumps changes the flow quantity and flow rate of blood through an organ, such as the kidney. For example, turning on one or both blood pumps changes the flow quantity and flow rate of blood through the kidney.

[0033] As shown in FIG. 2, pump 202 is a first blood pump including motor 204, rotor 206, housing 208, cannula 210, distal extension 212, and catheter 214. As shown in the embodiment of FIG. 2, pump 202 is positioned with distal extension 212 in the left ventricle and rotor 206 and rotor housing 208 in the aorta. When pump 202 is activated, it draws blood through inlet 216, through cannula 210, and out through housing 208 (also called rotor shroud) to unload the heart. Distal extension 212 acts to stabilize pump 202 within the ventricle. For example, distal extension 212 is pigtail or j-shaped. When pump 202 is activated, it unloads the left ventricle and increases pressure in the aorta, thereby increasing downstream arterial pressure. Pump 202 may be operated at a range of speeds to provide a range of flow rates and associated aortic pressure increases. For example, pump 202 is operated at a flow rate of approximately 1.5 L / min to 6 L / min. In one embodiment, pump 202 is operated at a flow rate of approximately 5 L / min. Pump 202 may be inserted percutaneously into the patient via the femoral artery or via the subclavian vein.

[0034] As shown in FIG. 2, pump 222 is a second blood pump that includes motor 224, rotor 226, housing 228, cannula 220, distal extension 222, and catheter 224. As shown in the embodiment of FIG. 2, pump 222 is placed in the inferior vena cava. When pump 222 is operated, it draws blood through inlet 236, through cannula 220, and out through rotor housing 228 (also called rotor shroud). Rotor housing 228 and rotor 226 are in the inferior vena cava, downstream of inlet 236, which is also in the inferior vena cava. In one embodiment, for example, as shown in FIG. 2, pump 222 includes distal extension 242 that stabilizes pump 222 in the inferior vena cava or at the junction between the inferior vena cava and the renal vein. For example, distal extension 242 is pigtail or j-shaped. Pump 222 also includes an anchoring mechanism 240 positioned on the cannula between inlet 236 and rotor housing 228 through which blood exits the pump. The anchoring mechanism 240 may both anchor pump 222 at a desired position along the inferior vena cava and partially occlude the inferior vena cava to allow operation of pump 222 across the anchoring mechanism. For example, anchoring mechanism 240 anchors pump 222 between about 1-5 centimeters downstream of the renal vein. In another embodiment, anchoring mechanism 240 anchors pump 222 between about 2-3 centimeters downstream of the renal vein. In one embodiment, anchoring mechanism 240 is a balloon that can be selectively inflated to at least partially occlude the inferior vena cava. For example, the size, shape, material, and position of the balloon on cannula 220 are selected to achieve different levels of occlusion within the inferior vena cava. In another embodiment, anchoring mechanism 240 is an expandable cage. For example, the anchoring mechanism 240 may be a self-expanding cage (e.g., Nitinol) that is surrounded by a sheath for insertion and then self-expands once the sheath is removed in situ. The cage braces against the wall of the inferior vena cava to securely fix the pump 222 in position.In one embodiment, the cage may taper proximally and distally along the cannula to partially occlude the inferior vena cava and may be covered with a biocompatible covering material.

[0035] The partial occlusion of the inferior vena cava, in combination with operation of pump 222 drawing blood from a location in the inferior vena cava and / or the renal vein to a location downstream of pump inlet 236, results in a pressure drop. The pressure drop may be measured as the pressure drop in the inferior vena cava upstream of pump 222 (e.g., in the immediate vicinity of the renal vein) or as the pressure drop in the renal vein. Alternatively, the pressure drop may be measured as the drop across the kidney between the arterial pressure going into the kidney and the venous pressure coming out of the kidney (e.g., in the renal vein).

[0036] Pump 222 may be percutaneously inserted into the patient's body via the femoral artery or via the subclavian vein. In one embodiment, pump 222 and pump 202 are inserted through different percutaneous access points. Alternatively, pump 222 and pump 202 are inserted through the same percutaneous access point (e.g., the subclavian vein).

[0037] In one embodiment, each pump (e.g., pumps 202, 222) includes a pressure sensor. For example, both pumps include an integrated pressure sensor, such as a differential pressure sensor, a piezoelectric pressure sensor, or an optical pressure sensor. In another embodiment, both pumps include a separate pressure sensor introduced on the pressure sensor wire, or a Swan-Ganz catheter. Alternatively, one of the pumps includes an integrated pressure sensor and the other pump uses a separate pressure sensor. Pump 202 may include an integrated pressure sensor for detecting pressure. For example, pump 202 may include a differential pressure sensor where one side of the sensor is exposed to the blood pressure on the outside of the inlet area and another side of the sensor is exposed to the pressure of the blood inside the cannula 210. In this embodiment, the sensor generates an electrical signal proportional to the difference between the two pressures, and the electrical signal is generated for display on a controller (e.g., an Automated Impella® controller). Alternatively, pump 202 may be introduced into the patient with a Swan-Ganz catheter for measuring pressure. Similarly, pump 222 may include an integrated pressure sensor to detect pressure. For example, pump 222 may include a differential pressure sensor where one side of the sensor is exposed to the blood pressure on the outside of the inlet area and another side of the sensor is exposed to the pressure of the blood inside cannula 220. In this embodiment, the sensor generates an electrical signal proportional to the difference between the two pressures, and the electrical signal is generated for display on a controller (e.g., an Automated Impella® controller). Alternatively, pump 222 may be introduced into the patient with a Swan-Ganz catheter to measure pressure.

[0038] Each pump (e.g., pumps 202 and 222) may be connected to a controller, such as an Automated Impella Controller®, that receives data from the pump and sensors associated with the pump (e.g., either integrated or separate sensors) and generates information about cardiac output and / or renal output for display to a user (e.g., a medical professional). As described below with respect to the embodiment of FIG. 3, information from the controller is used to determine if and when to stop operation of one or more pumps.

[0039] As described below with respect to FIG. 3, by operating pump 222 while pump 202 is operating, both the arterial pressure input to kidney 250 and the venous pressure output from kidney 250 can be adjusted. At least one advantage of this dual pump operation is that it can increase both the cardiac output and the arterial pressure input to kidney 250 and / or it can decrease the venous pressure exiting kidney 250. Thus, operating pump 202 while pump 222 is operating increases blood flow to the kidney and increases the amount of humoral factors reaching the kidney. Operating pump 222 while pump 202 is operating increases blood flow exiting the kidney. At least one advantage of this dual pump operation is that it can increase urine output and eliminate stress factors, including stress factors resulting from surgery, for example.

[0040] FIG. 3 illustrates an exemplary method 300 for improving renal function. In step 302, a first blood pump (e.g., pump 202 in FIG. 2) is inserted into the patient's heart. In step 304, the first blood pump is activated to increase aortic pressure. In step 306, a second blood pump (e.g., pump 222 in FIG. 2) is inserted into the patient's inferior vena cava. After the second blood pump is inserted, an anchoring mechanism is placed (e.g., anchoring mechanism 240 in FIG. 2). For example, the anchoring mechanism is a balloon surrounding a portion of the pump cannula (e.g., cannula 220 of pump 222 in FIG. 2). In this embodiment, the balloon surrounding a portion of the pump is inflated to anchor the pump in the inferior vena cava and partially occlude the inferior vena cava. In step 308, the second blood pump is activated while the first blood pump is activated. In step 312, the system determines whether a target renal parameter (e.g., blood pressure reduction in the renal vein) has been achieved at a location in the patient's renal vein or inferior vena cava. If the determination in step 312 is that the target renal parameter (e.g., blood pressure drop in the renal vein) has been achieved, operation of the second blood pump may be stopped (step 314). If the determination in step 312 is that the target renal parameter (e.g., blood pressure drop in the renal vein) has not been achieved, a second determination is made (step 310) regarding whether to adjust operation of the first blood pump and / or adjust operation of the second blood pump. For example, the speed of the first blood pump (e.g., pump 202 of FIG. 2) may be modified (e.g., increased or decreased) independently of the speed of the second blood pump. In one embodiment, the speed of the first blood pump is increased by about 1 L / min. Alternatively, the speed of the first blood pump is increased by about 2 L / min. Similarly, the speed of the second blood pump (e.g., pump 222 of FIG. 2) may be modified (e.g., increased or decreased) independently of the speed of the first blood pump. In another embodiment, the speed of both the first blood pump and the second blood pump may be increased. If the determination in step 310 is that no adjustment is required, the method returns to determining whether the target renal parameters have been achieved (step 312).For example, the target renal parameter may be a target pressure drop in the pressure in the renal vein or a target pressure drop across the kidney. For example, the first and second blood pumps may have to be operated for a longer period of time to achieve an effect on either the arterial or venous pressure, or both. If instead the determination in step 310 is that an adjustment to the operation of either or both of the first and second blood pumps is required, the method returns to step 308 where the first and second blood pumps are operated simultaneously.

[0041] For example, a pump controller (e.g., the controller of pump 222 and / or pump 202 in FIG. 2) is configured to run one or both auxiliary devices (e.g., pump 222 and / or pump 202 in FIG. 2) at respective rates to increase blood flow from the heart and to stimulate production of at least one humoral factor that binds to a renal receptor or a receptor of another organ to stimulate and / or regulate urine production and urine synthesis from the kidney. In one embodiment, both pumps (pump 222 and pump 202) are connected to a single controller, as described above with respect to FIG. 2. The controller may receive data regarding a renal parameter. For example, the renal parameter is the pressure drop at the outlet of the kidney. Alternatively, the renal parameter is the pressure drop across the kidney. As another example, the renal parameter is the creatinine level or the ANP concentration in the blood. In one embodiment, the controllers of both pumps communicate with each other.

[0042] In one embodiment, the controller may also compare the renal parameters to renal parameter thresholds. For example, the controller may continuously compare the renal parameters to the thresholds in near real-time. Alternatively, the controller may perform the comparison periodically. The thresholds may be input by a user. Alternatively, the thresholds may be retrieved by the controller from a database. For example, the database is a remote database with known clinical data for target renal parameter values. In one embodiment, the controller is configured to generate an indication for display that a threshold for a renal parameter has been reached. For example, the controller may generate an alarm. In another embodiment, the controller sends a message to a physician. In one embodiment, the physician may turn off one or more of the pumps based on the monitoring of the renal parameters. For example, the physician may turn off pump 222 while keeping pump 202 running when a renal parameter (e.g., pressure in the renal vein) reaches a threshold. In another embodiment, the controller detects that a renal parameter has reached a threshold and automatically turns off one or more of the pumps. At least one advantage of being able to determine when to turn off another pump is that the patient can be safely weaned off support and organs (e.g., kidneys) can be improved without damaging them by exposing them to high blood pressure for longer than necessary.

[0043] The foregoing is merely illustrative of the principles of the present disclosure, and the systems, methods, and devices of the present invention may be practiced in other than the manner of this description, which is presented for purposes of illustration and not limitation. It should be understood that the systems, methods, and devices disclosed herein, although illustrated for use in a system for an intracardiac heart pump, may also be applied to systems, methods, and devices for other implantable heart pumps or implantable cardiac assist devices.

[0044] Variations and modifications will occur to those skilled in the art after reviewing this disclosure. The various features described or illustrated above, including components thereof, may be combined or integrated into other systems. Additionally, certain features may be omitted or not implemented. The various embodiments described or illustrated above may be combined in any manner.

[0045] Examples of changes, substitutions, and alterations are ascertainable by one of ordinary skill in the art and can be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made a part of this application.

Claims

1. 1. A method for regulating renal function in a patient, comprising: inserting a first blood pump into the patient's heart; operating the first blood pump to increase aortic pressure; inserting a second blood pump into the patient's inferior vena cava; and operating the second blood pump and the first blood pump; Including, The method, wherein operation of the first and second blood pumps achieves a target pressure drop at a location within the patient's renal vein or inferior vena cava.

2. 2. The method of claim 1, wherein the step of operating the second blood pump comprises pumping the second blood pump while the first blood pump is pumping.

3. 3. The method of claim 2, wherein operating the first blood pump maintains or increases arterial pressure in the renal arteries.

4. 4. The method of claim 3, wherein operating the second blood pump maintains or reduces renal vein pressure.

5. 5. The method of claim 4, comprising operating a first blood pump to increase arterial pressure and operating a second blood pump to decrease renal vein pressure.

6. 3. The method of claim 2, wherein the location is a vascular junction connecting the patient's renal vein and inferior vena cava.

7. 3. The method of claim 2, wherein the target pressure drop increases blood flow through the kidney and increases renal output.

8. 8. The method of claim 7, wherein the target pressure drop is from about 4 mmHg to about 8 mmHg.

9. 8. The method of claim 7, wherein the target pressure drop is from about 5 mmHg to about 7 mmHg.

10. 3. The method of claim 2, wherein the target pressure drop corresponds to a blood pressure drop across the kidney.

11. 3. The method of claim 2, wherein the combined operation of the first and second blood pumps flushes humoral factors to the patient's renal receptors to stimulate increased urine output from the kidney.

12. The first blood pump A pump motor; a pump housing distal to the pump motor and surrounding a rotor; a cannula extending distally of the pump housing; an atraumatic extension extending distally from the cannula; 2. The method of claim 1, comprising:

13. A second blood pump A pump motor; a pump housing distal to the pump motor and surrounding a rotor; a cannula extending distally of the pump housing; 2. The method of claim 1, comprising:

14. 13. The method of claim 12, wherein the second blood pump further comprises an atraumatic extension extending distally from the cannula.

15. 13. The method of claim 12, wherein the second pump is positioned within the inferior vena cava such that a distal tip of the atraumatic extension extends to a position adjacent the outlet of the renal vein.

16. 10. The method of claim 1, wherein the first blood pump is inserted into a ventricle of the patient.

17. 2. The method of claim 1, wherein the modulation of renal function occurs during or after surgery.

18. a first mechanical circulatory support device configured to unload the ventricle, the atrium, or the atrium and the ventricle, or both atria and both ventricles; a second mechanical circulatory support device configured to be positioned within the vein and to be operated by pumping blood within the vein; a controller configured to operate both the first and second mechanical circulatory support devices; and Equipped with the first and second mechanical circulatory support devices are configured to achieve a target pressure drop in the renal vein when activated simultaneously; A system for improving kidney function.

19. The controller receiving arterial pressure from a first mechanical circulatory support device and venous pressure from a second mechanical circulatory support device; determining that a pressure drop in the renal vein is below a target pressure drop in the renal vein; and adjusting operation of at least one of the first mechanical circulatory support device and the second mechanical circulatory support device to achieve the target pressure drop in the renal vein.

20. The system of claim 18, configured to:

20. 20. The system of claim 18, wherein the target pressure drop is sufficient to increase urine production by the kidneys.

21. a control unit configured to operate the first mechanical circulatory support device at a rate that increases blood flow from the heart and stimulates production of at least one humoral factor that binds to a renal receptor or a receptor of another organ to stimulate and / or regulate urine production and urinary fluid composition from the kidney.

20. The system of claim 18, further comprising:

22. 20. The system of claim 18, wherein the first and second mechanical circulatory support devices are blood pumps.

23. a second mechanical circulatory support device comprising: A pump motor; a pump housing distal to the pump motor and surrounding a rotor; a cannula extending distally of the pump housing; an anchoring device configured to anchor the second mechanical circulatory support device to the inferior vena cava during operation of the second mechanical circulatory support device; 20. The system of claim 18, comprising:

24. 24. The system of claim 23, wherein the anchoring device is a balloon surrounding a portion of the cannula.

25. 25. The system of claim 24, wherein the balloon is configured to partially occlude the inferior vena cava when inflated.

26. 20. The system of claim 18, wherein the second mechanical circulatory support device is positioned with the inlet positioned at the location where the renal veins connect to the inferior vena cava.

27. 20. The system of claim 18, wherein the first mechanical circulatory support device further comprises a first pressure sensor configured to measure arterial blood pressure.

28. 28. The system of claim 27, wherein the second mechanical assistance device comprises a second pressure sensor configured to measure venous pressure.

29. 30. The system of claim 28, wherein the difference between the measured venous pressure and the measured arterial pressure increases when both the first and second mechanical circulatory support devices are operating simultaneously.

30. 1. A method for improving renal function in a patient, comprising: inserting a first blood pump into the patient's heart; operating the first blood pump; inserting a second blood pump into the patient's inferior vena cava; operating the second blood pump while the first blood pump is operating; monitoring renal parameters; and terminating operation of the second blood pump when the renal parameter reaches a target level. A method comprising:

31. 31. The method of claim 30, wherein the renal parameter is creatinine level or ANP concentration in blood.

32. 31. The method of claim 30, wherein the target level for the renal parameter is a function of aortic pressure.

33. 31. The method of claim 30, wherein the renal parameter is renal venous pressure.

34. 34. The method of claim 33, wherein the target level for renal vein pressure is less than 15 mmHg.

35. 31. The method of claim 30, wherein the renal parameter is pressure drop across the kidney.

36. Renal parameters are measuring arterial pressure; Measuring venous pressure; and calculating a pressure difference between said measured arterial pressure and said measured renal venous pressure.

31. The method of claim 30, wherein the method is determined by:

37. determining when the calculated pressure differential reaches a threshold value; 37. The method of claim 36, further comprising:

38. 40. The method of claim 37, wherein the first blood pump is in communication with the first controller and the second blood pump is in communication with the second controller.

39. 40. The method of claim 38, wherein the first controller and the second controller communicate to determine a pressure difference between the measured arterial pressure and the measured renal vein pressure.

40. 31. The method of claim 30, wherein the first blood pump is inserted into a ventricle of the patient.

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