Chronic heart failure device

Abstract

A device comprising: a catheter or implanted device having a tip configured to be located within the distal JVC, between the confluence of the common iliac veins and the testicular / ovarian veins; and a flow restriction mechanism at or near the tip of the catheter or implanted device configured to be inflated with fluid or gas, and deflated by a control unit in order to optimize cardiac preload and cardiac output.

Description

CHRONIC HEART FAILURE DEVICECLAIM OF PRIORITY

[0001] This application claims priority’ to U.S. Provisional Patent Application No. 63 / 616,849, filed January 2, 2024, and U.S. Provisional Patent Application No. 63 / 639,997, filed April 29, 2024, each of yvhich is incorporated by reference in its entirety.FIELD

[0002] The invention features a device for treating chronic heart failure.BACKGROUND

[0003] Many of the symptoms and sequelae of heart failure are mediated through increased volume and pressure yvithin the cardiac chambers and venous system. These lead to cardiac remodeling and gradual worsening of heart failure, as well as elevated venous pressures leading to shortness of breath through elevated pulmonary pressures, hepatic dysfunction through hepatic vein congestion, worsening renal failure through renal vein congestion among a myriad of other issues. Patients with heart failure are a leading source of hospital admissions and are frequently subject to multiple re-admissions in order to manage acute exacerbations of their disease leading to a significant burden on our hospital systems through both staffing and costs. Currently, there are no device options available on the market to manage preload for heart failure patients, however there are several in development, including devices from preCARDIA, Doraya, and Venodynamics. However, all of these systems are designed for use during inpatient hospital admissions. A functional preload management device has the potential to reduce the duration of hospital admissions, as well as reducing the frequency of admissions if made suitable for ambulatory management.

[0004] SUMMARY

[0005] This Summary introduces a selection of concepts in simplified form that are described further below in the Detailed Description. This Summary neither identifies key or essential features, nor limits the scope, of the claimed subject matter.

[0006] In one aspect, a device can include a catheter or implanted device having a tip configured to be located within the distal inferior vena cava (IVC), between the confluence of the common iliac veins and the testicular / ovarian veins, and a flow restriction mechanism, for example, a balloon, at or near the tip of the catheter or implanted device configured to be inflated with fluid or gas, and deflated by a control unit in order to optimize cardiac preload and cardiac output.

[0007] In another aspect, a device can include a compressive device located adjacent to the extravascular distal IVC. between the confluence of the common iliac veins and the testicular / ovarian veins or another major venous structure, and a compressive mechanism (e.g., a balloon, cinch, or snare, or other structure) configured to reduce the cross-sectional area of the IVC or other large venous structure when activated in order to optimize cardiac preload and cardiac output.

[0008] In another embodiment, as opposed to an intravascular catheter based balloon modulation of preload, an implanted extravascular device such as a balloon or cinch / snare can be placed between the confluence of the common iliac veins and the testicular / ovarian veins along the IVC, or another viable vascular structure. The activation of this device can reduce the cross sectional area of the IVC or other large vein thus altering the flow dynamics of the vein and allowing for the optimization of cardiac preload.

[0009] In another embodiment, the device can include a retrievable and adjustable flow restrictive mechanism, for example, balloon, valve, or other structure. The device can be located in the distal IVC as described above. In this embodiment, the fixation mechanism can include radially expanding struts that stabilize the device in a preferred location. This fixation mechanism can be similar to how IVC filters for deep vein thrombosis (DVT) are placed. Important aspects of this implementation is that the device can be designed to be easily retrieved via percutaneous mechanisms as well as all components of the flow restriction mechanism being intravascular and all essential extravascular components performing their functions wirelessly.

[0010] In certain embodiments, the device can include a catheter tip containing piezoelectric crystals or pressure sensors to sample IVC and aortic blood flows as feedback mechanisms to determine optimal flow restriction. The flow restriction can be adjusted, for example, byaltering balloon size. Sensors may also include volume or waveform analysis to estimate preload and changes in cardiac output.

[0011] In certain embodiments, the compressive device can include piezoelectric crystals, pressure sensors, volume analysis, weight, or waveform analysis to sample IVC and arterial blood flows, pressures, or other variables as feedback mechanisms to determine reduction of the cross-sectional area of the IVC or other large venous structure. The reduction of the cross-sectional area can be adjusted, for example, by altering balloon size.

[0012] If the device does not include intravascular piezoelectric crystals contained within the catheter, the device control mechanism can include piezoelectric crystals or one or more pressure sensors placed extravascularly, onto the adventitia of the IVC and aorta, whose purpose is to sample the velocity patterns of IVC and aortic blood flows to determine the optimal amount of IVC (or other large vein) cross sectional area reduction.

[0013] In certain embodiments, the compressive device includes piezoelectric crystals, pressure sensors, or other sensors essential to the function of the device to estimate preload, cardiac output, and optimal device activation patterns are surgically implanted into the adventitia of the IVC and aorta to sample flow patterns.

[0014] In certain embodiments, the device can include a combination of accelerometers and gy roscopes located within the device that are configured to relay body position in space (for example, supine, sitting, standing) and a spectrum of activity levels (for example, still, low- level. high-level activity) in real-time.

[0015] In certain embodiments, the device can include an electrocardiogram (EKG) which can determine heart rate and heart rate variability7to aid in the determination of a physiologic state requiring increased venous return, for example, exercise.

[0016] In certain embodiments, the assessment of preload is not Doppler waveforms as described above, but could be other modalities including but not limited to direct venous pressures, pressure change or gradient across device, IVC volume, change in weight or peripheral venous waveform analysis.

[0017] In certain embodiments, the device can include a catheter or a retrieveable stmt system having a surface compostition, both in terms of materials and shape, configured to mitigate the risk of thrombosis on a foreign device located in the blood stream.

[0018] In certain embodiments, the balloon or flow restrictive mechanism can be completely intravascular and stabilized with a set of radially expanding stmts. The stmts can be similar to the stabilization mechanism of DVT filters. In this iteration, no aspect of the device crosses the vascular wall. All essential components are either integral to the intravascular component or exert their effect via a remote mechanism.

[0019] In other embodiements, the marterials should be optimized to reduce the formation of fibroses around a foreign body implanted around a vascular structure.

[0020] In certain embodiments, a method can include controlling blood flow in a subject using a device described herein.

[0021] In certain embodiments, a method can include controlling blood flow and limiting negative sequelae of the device via activation / inactivation patterns in a subject using a device described herein.

[0022] The following Detailed Description references the accompanying drawings which form a part this application, and which show, by way of illustration, specific example implementations. Other implementations may be made without departing from the scope of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a schematic side view of an inflated device described herein.

[0024] FIG. 2 is a schematic side view' of a deflated device described herein.

[0025] FIG. 3 is a schematic top view of an inflated device described herein.

[0026] FIG. 4 is a schematic top view of a deflated device described herein.

[0027] FIGS. 5A-9D feature embodiments of an extravascular device as described herein.DETAILED DESCRIPTION

[0028] The concept is a device which aims to improve the treatment of either acute, chronic, or acute on chronic heart failure. As discussed below, management of venous blood volume or pressure can improve the symptoms of heart failure and reduce the sequelae of acute or chronic disease. A device which was able to redistribute venous blood from the proximal IVC and cardiac chambers, thereby reducing pressures in the pulmonary, hepatic, mesenteric, and renal vasculature, into the lower extremity vasculature or other peripheral vascular beds where it should cause less sequelae from the disease. After being enacted, the redistribution in flow should allow for a more favorable position on the Frank-Starling curve for a failing heart and improve cardiac output. It should also improve organ perfusion and urine output through both improved cardiac output and less venous congestion. A device could accomplish this via balloon inflation, or adjustable mechanics (fins / valves / channels / cinch / snare) that serve to reduce flow through back pressure or turbulence. Also, an extravascular balloon, cinch, snare, or other compressive device, couldreduce the cross sectional area of the IVC or other large vein and achieve similar changes to venous flow dynamics. These flow altering mechanisms should be adjustable through a wired or wireless external controller and adjustable based on activity levels, symptoms, or potentially data acquired from the device itself about pressure, flow, volume, waveform morphology, or weight. The device could potentially self-regulate via implanted wired control mechanism based on that data. The device can be placed into or onto the IVC in between the convergence of the iliac veins and the renal veins so as to not cause congestion in the renal, hepatic, or mesenteric vessels. It may also be placed around another major vascular structure if deemed suitable. It should be implantable and retrievable through femoral vein or internal jugular access by either interventional radiology or interventional cardiology or surgically implanted by a vascular or cardiothoracic surgeon.

[0029] Of the devices currently in development, the designs have flaws that limit their application in the treatment of heart failure on an ambulatory or outpatient basis. For example, a Cardioflowtech device is a proximal IVC device. The balloon location appears to be proximal to the renal veins. The Venodynamics device appears be in a similar location as our proposed device, however there are externalized catheters and control mechanisms that make it unsuitable for outpatient management. A preCARDIA device is an SVC location device that could lead to venous congestion in the head leading to reduced perfusion of the brain. The design may not unload the venous congestion of the kidneys, liver, and gut. By locating the flow limiting device in a more distal location in the IVC, between the confluence of the iliac veins which forms the IVC and the renal veins, the device described within provides additional benefits which existing attempts at mechanical preload management fail to offer. By locating the balloon in the above location, it is able to both augment cardiac output by optimizing cardiac preload and reduce venous congestion in vital organs such as the liver, kidneys, intestines, and brain. These benefits combine for enhanced perfusion to the aforementioned vital organs via improved perfusion pressure across the capillary beds. This should reduce non-cardiac sequelae of heart failue including chronic kidney disease, liver dysfunction or cirrhosis, cardiointestinal syndrome, pulmonary hypertension, and cognitive decline from low cerebral perfusion. The Doraya catheter by Revamp medical is a flow altering device placed in a location similar to the device proposed within, however it lacks the feedback mechanisms which contribute to the safety and suitability for a wider patient population and ambulatory management of heart failure of the device herewithin. Other devices primarily serve to augment cardiac output by optimizing cardiac preload,however they likely have minimal or even deleterious effects on venous congestion in vital organs outside of the heart. An additional benefit to this location is the ease of sampling both venous and arterial flows, pressures, and volumes to manage the device settings. The IVC and aorta are directly adjacent in this location allowing doppler ultrasound signals to be easily sampled from the IVC and aorta for feedback on the effects of device settings, body position, and activity7levels. With the extravascular embodiment, the relative proximity of the flow regulator implantation site and the doppler signal sites, make for an easier surgical exposure than if they were located in more disparate locations.

[0030] Outside of optimizing location of the flow regulating mechanism, other devices utilize simplisitic control mechanisms that are ill suited for outpatient management of chronic heart failure. The preload needs of an outpatient chronic heart failure patient are quite complex and everchanging. The device described within, and its unique control mechanisms provide a device uniquely suited for both inpatient and outpatient heart failure management. Assessments of demand are made by accelerometers and EKG monitoring. Assessments of preload needs in relation to body position are made with a combination of accelerometers and gyroscopes which can differentiate supine, sitting, and standing patients. Assessments of venous flow, pressures, volumes, and waveform analysis can be made with pulse wave doppler sampled within the IVC or other sensor technologies and this device can determine how these flows and other data points relate to the cardiac cycle. Estimations and assessments of changes in cardiac output or systemic pressures are made by continuous or pulse wave doppler sampling of the abdominal aorta, or with direct pressure measurement or indirect pressure measurement

[0031] In order to mitigate the effects of redistributing blood volume to the lower extremities, the device can also perform a regular calibration maneuver while the patient is supine. By performing the maneuver, likely by a series of flow restrictions followed by releases and assessing the subsequent flow, the device can signal to the patient or their clinician of the need of additional volume management strategies such as diet changes or changes to diuretic regimen.

[0032] Additionally, the pattern, timing, and degree of device activation and inactivation can be optimized to save battery life, reduce risk of patient falls or sudden changes in cardiac output, reduce the risk of device related thrombosis, and reduce lower extremity edema.

[0033] FIG. 1 features a schematic side view of an inflated device described herein. FIG. 1 depicts a coronal view of the device 10 contained within the distal inferior vena cava 12 witha flow restriction mechanism or balloon 24 in inflated state. Catheter 20 includes tip 22 and flow restriction mechanism 24 proximate to the tip 22. Stabilization hooks or struts 30 hold device 10 in place. Control unit 40 functions as described to take input from sensors and other sources. The fluid or gas filled balloon can be in a maximally inflated state surrounding distal tip of the device. The flow restriction mechanism, for example, the ballon, can be a spherical balloon (for example, shown in FIG. 1), or can be ellipsoid in shape. In other embodiments of the device, the balloon could not cover the tip of the device containing the ultrasound components. The distal tip of the device can contain pulse wave and continuous wave Doppler devices (shaded black areas). The Doppler device can be oriented in a number of different to optimize meaningful data collection.

[0034] FIG. 2 features a schematic side view of a deflated device described herein. FIG. 2 depicts a coronal view of the device contained within the distal inferior vena cava with the balloon in a deflated state. Catheter 20 includes tip 22 and flow restriction mechanism 24 (shown in a deflated state) proximate to the tip 22. Stabilization hooks or struts 30 hold device 10 in place. Control unit 40 functions as described to take input from sensors and other sources. Device 10 can include sensors 50, which can be piezoelectric crystals, pressure sensors, pulse wave Doppler, continuous wave Doppler, aerotic velocity time integral (VTI) or other sensing modality. Catheter 20 can include conduit 60 for providing saline, power, ultrasonic signal or other external stimulus. The fluid or gas filled balloon can be in a deflated state surrounding distal tip of device. The flow restriction mechanism, for example, the ballon, can be a spherical balloon (for example, shown in FIG. 2), or can be ellipsoid in shape. In other embodiments of the device the balloon can not cover the tip of the device containing the ultrasound components.

[0035] FIG. 3 features a schematic top view of an inflated device described herein. FIG. 3 depicts an axial view of the device contained within the distal inferior vena cava with a balloon in an inflated state. Catheter 20 includes tip 22 and flow restriction mechanism 24 (shown in an inflated state) proximate to the tip 22. Stabilization hooks or struts 30 hold device 10 in place. Control unit 40 functions as described to take input from sensors and other sources. The fluid or gas filled balloon can be in a maximally inflated state surrounding distal tip of device.

[0036] FIG. 4 features a schematic top view of a deflated device described herein. FIG. 4 depicts an axial view of the device contained within the distal inferior vena cava with a balloon in a deflated state. Catheter 20 includes tip 22 and flow restriction mechanism 24(shown in a deflated state) proximate to the tip 22. Stabilization hooks or struts 30 hold device 10 in place. Control unit 40 functions as described to take input from sensors and other sources. The The fluid or gas filled balloon can be in a deflated state surrounding distal tip of device.

[0037] The device can include a conduit for fluid / gas to inflate and deflate the flow restriction mechanism or ballon. A flexible conduit can serve as conduit for fluid / gas between reservoir and balloon, anchoring of device in its location within IVC, data transmission from Doppler components, and other data sources such as EKG and gyrometer / accelerometer. In other embodients the fluid or gas storage for balloon inflation is wholly contained within the device or balloon as a change in balloon shape while maintaining the same volume can induce the appropriate pressure gradient or flow restriction across the device.

[0038] In certain embodiments, a series of hooks or struts can limit movement of device tip or entire device within the IVC. In some iterations the struts are the only fixation mechanism as there are no structures crossing the vascular wall after implantation.

[0039] In certain embodiments, a control unit can be implanted on patient’s flank which contains fluid / gas reservoir for balloon, processing cababilities for data interpretation and decision making, possible location of EKG and gyrometer / accelerometer, Bluetooth / Wi-Fi cababilities for patient and clinician access and device management, battery. In other embodiements, this control unit can include associated functions as above may be completely wireless and not implanted.Device Anchoring Mechanism and Location:

[0040] The device will be anchored in the distal abdominal IVC in between the confluence of the common iliac veins and the junction of the IVC with the right testicular / ovarian vein (also distal to renal veins). This allows the device to unload venous pressure from critical organs (liver, kidneys, intestines) and redistribute that volume to areas of the body of comparatively less consequence (bilateral lower extremities). This allows the device to improve both cardiac output by optimizing preload and organ perfusion by reducing venous pressure thereby improving an organs perfusion pressure (Mean Arterial Pressure - Venous Pressure). This redistribution allows a patient and their physician to optimize diuretic therapy, improve a diuretics performance, and alter a patient’s diet in order to return their volume state to a more appropriate level.

[0041] In one embodiement, the device is anchored in position by 4-6 hooks which selfexpand radially (similar to IVC filters) to secure the device to the walls of the vena cava. Also potentially securing the device via tether is the cable connecting the balloon aspect of the device to its power source implanted under the skin. Also within this cable are the connections for the ultrasound devices, as well as the conduit for saline to move between the inflatable balloon and its reservoir within the battery pack. However, in some embodiments the only fixation device can include the self-expanding struts.

[0042] Another implementation of the device is that of a completely intravascular design, which combines a flow limiting balloon or valve with self-expanding struts to hold the device in place. This implementation can be retrieved via percutaneous mechanisms. The control and powder mechanisms of this device can perform their functions wirelessly.

[0043] In the extravascular embodiment, the flow regulating mechanism can be anchored adjacent to or surrounding the IVC at the same location described above or another major vascular structure. The anchoring mechanism itself could be but is not limited to a plate and screw? arrangement attaching the device to the vertebral body, or any other mechanism of securement relative to the adjacent structures.

[0044] The device described within will need to utilize a variety of specialized materials in order to achieve its goal of safely and effectively optimizing a patient’s cardiac preload over an extended duration as an outpatient. The balloon inflation / deflation mechanism needs a driving fluid or liquid. Other systems have typically utilized gases to achieve this, namely helium, carbon dioxide, or air, all of which may be appropriate for this system depending on the ultimate characteristics required, namely efficient balloon control over an extended period of time, all while having minimal physiologic consequences in case of balloon rupture. A biocompatible liquid may also be used. Liquids can be expected to have slower inflation / deflation times due to greater drag, but this may be less relevant as the frequency of balloon changes is expected to be lower than in competing systems. The surface of the system can need to be designed to limit the risk of clot formation. This may be accomplished in several ways. First, the shape of the catheter and flow restriction mechanism (e.g. balloon) can be designed to limit the stagnation of blood. The surface can be coated with a variety of materials to achieve a bioactive or biopassive coating, typically albumin, heparin, or other proprietary compounds. The surface could also be designed to encourage endothelization providing a surface similar to one’s own blood vessels. The inflation and deflation pattern may also be utilized to limit the stagnation of bloodflow' and thus reduce the risk of thrombusformation around the device. The casing containing the ultrasound components, drive line, and any other input / output mechanisms needs to be a flexible and biocompatible polymer. Where the ultrasound beams are expected to be transmitted the casing needs to allow for ultrasound beams to move efficiently through the casing and into the surrounding tissues and back without significant signal loss. Finally, the balloon itself requires a durable, flexible, biocompatible material that is able to limit clot formation while being able to withstand repeated inflation / deflation cycles without rupture. Ideally, the balloon can also limit the leaking of the driving fluid so the system may not require frequent refilling of driving fluid. Another form of thrombus prevention can be relocating the device and its control mechanisms from the intravascular IVC, to the adjacent extravascular tissues, eliminating the contract of foreign implanted material to the proteins involved in the coagulation cascade. In this case, the materials can be designed to limit the formation of scar tissue, or fibrosis, surrounding the device and vein, which may cause permanent flow restrictions.

[0045] The device can be placed into the distal IVC via Sei dinger technique. The femoral vein can be accessed via needle. Afterwich, a wire can be threaded into the IVC. Once the wire is confirmed to be positioned appropriately, either via ultrasound or fluoroscopy, a series of catheter dilations can be performed before finally threading the device into position over the wire. The final position in the distal IVC can be confirmed with fluoroscopy and possibly IV contrast. Before allowing the radially expanding hooks to deploy, confirmation of appropriate Doppler signals in the IVC and aorta will be obtained. After this, stabilization of the device location will be achieved with the raidally expanding hooks. The proximal end of the device will then be tunneled subcutaneously to the flank, where it will be connected to the control device containing the driving fluid reservoir, CPU to interpret the inputs and determine the appropriate balloon alterations, accelerometer / gyroscope unit, and electrocardiography lead. This control device is also implanted subcutaneously onto the flank.

[0046] Alternatively, placement of the device can be similar to the above iteration, however all necessary components are intravascular. This iteration can have no connecting catheter which required tunneling. The fluid or gas to change the size of the balloon can also be self- contained intravascularly. It can either contain the entire control mechanism or communicate with the control device via Wi-Fi, Near Field Communication, or Bluetooth.

[0047] In the extravascular embodiment, a surgical as opposed to percutaneous placement can be utilized. It can likely be accomplished via Pfannenstiel incision in the lower abdomenfollowed by dissection and mobilization of organs and vessels to expose the abdominal IVC, aorta, and lumbar vertebrae where the device and control mechanisms can be secured.Balloon Design:

[0048] A hypothetical balloon shape could a biocompatible spherical balloon containing saline or gas which is adjacent to or surrounds the tip of device in the IVC. Contained within the tip of the device are the primary components for controlling the size of the balloon via monitoring IVC and aortic blood flow, piezoelectric cry stals for emitting and receiving pulse wave and continuous wave doppler or other modalities such as pressure sensors. The monitoring of IVC and aortic blood flow or pressure can occur in real time. The aortic blood flow at the level of the abdominal aorta can easily be sampled from a device positioned within the distal IVC. By utilizing continuous or pulse wave doppler from a set of piezoelectric crystals in the tip of the device, tracings of aortic blood velocity over time can be created. The integral of these curves, or the Velocity-Time Integral (VTI), corresponds to the height of the column of blood that moves through the abdominal aorta with each beat of the heart. The abdominal aortic VTI fluctuates proportionally with the VTI at the Left Ventricular Outflow Tract and is therefor an excellent surrogate for monitoring the effects of balloon changes on cardiac output. Changes seen in abdominal aortic VTI can then be used to optimize preload via the balloon mechanism. Pulse wave doppler sampling of IVC flows gives an indication of varying degrees of fluid overload. Essentially, the more volume overloaded a patient is, the effects of the cardiac cycle on venous flows will be seen further and further away from the right atrium, as a more congested venous system propagates a fluid wave more efficiently. The IVC pulse wave doppler sampling can also be used in conjunction with the gyrometer and accelerometer to detect body position changes resulting in rapid changes to IVC venous flow s. Alternatively, instead of Doppler signals, direct or indirect pressure, volume, flow; patient weight, or w aveform analysis measurements of the IVC and aorta can be useful surrogates to guide the management of the device. Finally, the IVC sampling will be used in the periodic calibration protocol, where IVC flows or pressure are sampled after a balloon inflation / deflation series. This allows diuretic therapy to be tailored by the patient and their clinician. In order to synthesize this data and determine the appropriate management response, a processing unit will be contained within the control unit on the patients flank or a wireless remote controller. This processing unit will be able to interpret the real time data from the pulse wave and continuous w ave dopplers, EKG, gyrometer / accelometer, or any other associated sensors to determine the appropriate changesto make to the balloon size via the contained pump and drive line connected to the balloon. This control unit will be able to be accessed via cell phone application or Bluetooth or Wi-Fi enabled proprietary monitoring device so that the patient and their clinician can monitor the device's function and make alterations to it on an as needed basis. The device can be anchored to the IVC via self-expanding hooks and possibly the “tether’' which links the balloon and sensors housed in the tip of the device to the control unit and reservoir. The size of the balloon can be adjusted via infusion or extraction of saline or gas from the reservoir housed in the control unit. The shape of the balloon can most likely take the shape of a sphere or ellipsoid. However, the balloon could take any number of forms based on their performance in maintaining laminar as opposed to turbulent flow. Laminar flow can be encouraged via several mechanisms. The balloon shape is designed to minimize the angle of incidence when the blood contacts the balloon allowing for a more laminar flow pattern. This is achieved by utilizing an ellipsoid as opposed to spheroid balloon shape. The surface of the catheter is also designed to reduce drag. This is accomplished by utilizing materials that reduce buildup of proteins and other substances that increase the irregularity of the device surface. By minimzing drag, fewer eddies are formed which reduces turbulent flow. Ideally, a shape can be selected that is able to maintain somewhat laminar flow in all states of inflation / deflation as this can minimize risk of clot formation. See attached FIGS. 1-4.

[0049] In an extravascular embodiment, a wholly or partially circumferential compressive mechanism, likely a balloon or cinch, can be secured adjacent to or around the abdominal IVC between the confluence of the iliac veins and the renal veins. Upon activation, this compressive device can engage with the external surface of the IVC to reduce the cross- sectional area of the vessel at that location. This allows for the optimization of cardiac preload as described above. The surfaces of such an implantable device can be designed to limit the formation of tissue fibroses that may lead to permanent restrictions of venous flow.Pronged Feedback Mechanism for Control of Preload:

[0050] Pulse Wave Doppler Oriented Along IVC Flow to Determine Preload (Exact Location of Sampling Flexible): The proposed device utilizes a set of piezoelectric crystals whose ultrasound beams are oriented along the axis of the IVC. These allow the device to measure the velocity and direction of blood flow at a specific point within the IVC. Various levels of fluid balance (hypovolemia, euvolemia, mild fluid overload, and severe fluid overload) demonstrate different patterns of IVC flow at various points within the IVC.Essentially, the more volume overloaded a patient is, the effects of the cardiac cycle on venous flows will be seen further and further away from the right atrium, as a more congested venous system propagates a fluid wave more efficiently. These flow patterns are related to the cardiac cycle, so a single lead EKG could be housed within the control unit or another location on or within the patient to better characterize IVC flow patterns. Based on where the sampling occurs, these flow patterns can then be used as an input for training an Al -enabled algorithm for optimal pre-load management achieve by determining the optimal balloon size or optimal reduction of cross-sectional area by external compression. Flow pattern alterations can also be seen in changes in body position and activity levels, which can further optimize algorithmic control of pre-load. These flow patterns can be sampled and interpreted in real-time to make rapid changes to balloon size to maintain appropriate venous return and cardiac output. Pulse wave doppler sampling of IVC flows gives an indication of varying degrees of fluid overload. The IVC pulse wave doppler sampling can also be used in conjunction with the gyrometer and accelerometer to detect body position changes resulting in rapid changes to IVC venous flows. Finally, the IVC sampling will be used in the periodic calibration protocol, where IVC flows are sampled after a balloon inflation / deflation series. This allows diuretic therapy to be tailored by the patient and their clinician. In order to synthesize this data and determine the appropriate management response, a processing unit will be contained within the control unit on the patients flank. This processing unit will be able to interpret the real time data from the pulse wave and continuous wave dopplers, EKG, and gyrometer / accelometer to determine the appropriate changes to make to the balloon size via the contained pump and drive line connected to the balloon. This control unit will be able to be accessed via cell phone application or Bluetooth or Wi-Fi enabled proprietary' monitoring device so that the patient and their clinician can monitor the device’s function, measurements of patient’s fluid balance, and to make alterations to the device on an as needed basis. Alternatively, assessment of a patient’s preload can be made with pressure sensors in the device which measure both pre and post device venous pressures. These can be correlated to systemic blood pressure or surrogates of cardiac output to determine individual preload needs. Other modalities of assessment of preload include volume measurements, flow measurements, patient weight, and peripheral or central venous waveform analysis, all of which may be used in this device to determine an individual’s preload needs.Continuous or Pulse Wave Doppler Oriented along Abdominal Aortic Flow to Determine Effects on Cardiac Output:

[0051] In conjunction with monitoring pressure differential, IVC blood velocities, waveforms or other assessments of preload, our device utilizes a second set of piezoelectric crystals whose beams are oriented along the flow axis of the abdominal aorta, which is immediately adjacent to the IVC where our device is located, making the IVC an ideal location for placement of the device. Utilizing continuous or pulse wave doppler at this location allows the device to monitor the velocity of blood in the aorta throughout the cardiac cycle in real time. Calculating the area under the curve of the blood’s velocity vs. time, allows the device to monitor the height (or distance) of the column of blood moving through the abdominal aorta with each beat of the heart. This velocity -time integral (VTI) varies with preload, contractility, and afterload. The abdominal aortic VTI fluctuates proportionally with the VTI at the Left Ventricular Outflow Tract (the last section of the heart blood passes through before exiting via the aortic valve) and is therefore an excellent surrogate for monitoring the effects of balloon changes on cardiac output. Changes seen in abdominal aortic VTI can then be used to optimize preload and cardiac output via the balloon or flow restriction mechanism. Alternatively, other surrogates of cardiac output such as systemic blood pressure. VTI in other locations, or bioreactance mechanisms might be used in conjunction with other modalities to estimate the device’s effects on cardiac output.

[0052] Along with monitoring the balloon’s effects on cardiac output (via monitoring the abdominal aorta velocity -time integral) this aspect of the device allows the Al-enabled algorithm to monitor for the need of a “Demand” mode. As the abdominal aortic VTI fluctuates with changes to myocardial contractility, heart rate, and cardiac preload, its measurement can aid in identifying states of high physiologic metabolic demand. Essentially, an increase in heart rate and VTI typically corresponds with high demand physiologic states such as exercise. When a patient begins to engage in physical activity, their heart rate and contractility should increase, thus generating higher VTI’s and higher heart rates, both of which are monitored by the doppler function of our device, when this set of parameters is encountered, our device can then be able to modulate balloon size to allow for more preload to return to the heart to facilitate exercise. In order to differentiate between these states of high metabolic demand and other causes of higher heart rates, such as increasing levels of volume overload, cardiac arrhythmias, or myocardial ischemia, models will need to be created in order to train the decision making mechanism on appropriateballoon inflation states. Different patients will need different levels of preload to maintain optimal cardiac output, as they have different filling pressures required to achieve different end diastolic volumes. As such, utilizing a strictly algorithmic approach is likely insufficient, and the decision making model will likely need to be trained utilizing individual patient data in order to achieve optimal outcomes via optimal cardiac filling.

[0053] Gyroscope / Accelerometer: As the third prong of feedback mechanism, within the battery / control / reservoir unit can be a gy roscope and accelerometer which enable the device to determine body position and activity level changes. Placement of this system should be able to distinguish between various states of patient positioning, whether they are supine, sitting, or standing. Therefore, there may need to be multiple sets of sensors to differentiate between certain body positions. Preferably this system can be integrated into the device to minimize potentional connectivity issues associated with sourcing this data from external devices. One of the highest risk periods for drops in cardiac output secondary to low preload states (potentially causing falls) is when a patient can move from supine to standing positions relatively quickly, thus leading to a drop in preload. A gy roscope / accelerometer should provide our control mechanism with immediate feedback to alter the balloon’s size. If the control unit relied on falling abdominal aortic VTI measurement (or other surrogates of cardiac output) it can potentially lead to delays in management or an increased risk of falls, as falling cardiac output is a “late” indication of decreased preload. In addition to moving from recumbent to standing positions as vice-versa, an accelerometer could also aid in the “Demand” function of the algorithm, aiding in identifying increases in physical activity', or other physiologic states requiring higher venous return. In response to these states which require more venous return, the algorithim should decrease the size of the balloon allowing for increased flow back to the heart.

[0054] EKG: A single lead EKG will be contained within the device to serve several functions. In detecting changes in heart rate and variability, it aids in the algorithm which detects increased physiologic demand necessitating greater venous return. In identifying various points in the cardiac cycle (atrial depolarization, ventricular depolarization, ventricular repolarization) the EKG works in tandem with pulse wave doppler of the venous system in order to detect varying degrees of volume overload.

[0055] The system can provide in-patient or out-patient management of acute, chronic, or acute on chronic heart failure by mechanical control of venous return by IVC balloon or compression in order to optimize cardiac preload, filling pressures, and cardiac output.

[0056] In certain embodiments, algorithms and models can determine the ideal balloon size or compression to optimize cardiac preload. The algorithm can also be utilized to determined optimal patterns of inflation and deflation to protect against thrombus formation, optimal diuretic management, reduction in patient falls, and reductions in sequelae of device usage such as reducing the stimulus for venous remodeling that may limit the effective duration of treatment. The algorithm can utilize data generated by the inherent pulse and continuous wave Doppler systems, accelerometers, gy roscopes, pressure sensors, volume analysis, patient weight, and / or EKG to determine whether more or less venous return is needed at any- given moment and then utilize a pump to inflate or deflate the IVC balloon or reduce compression. As various patients have different filling needs, an Al-enabled decision model can be trained with individual patient data after the implantation process.

[0057] A calibration procedure can determine when lower extremity venous pressures and fluid levels are increasing to the point that alterations in medical therapy, through the alterations of diuretic therapy by the patient or their clinician, are needed to optimize the patient’s fluid balance.

[0058] In certain embodiments, a demand function associated with the device can determine physiologic states requiring higher venous return and adjust the size of the balloon or compression appropriately in response.Extravascular IVC Compression Device

[0059] In another embodiment of the device, the method of IVC flow" modulation moves from being an intravascular device, to being an extravascular IVC compression mechanism. The mechanism could be but isn’t limited to, an extravascular balloon or snare which either completely or partially encircles the distal IVC in a similar position as described above. When the mechanism is activated, it causes external compression of the IVC leading to reduced flow, similar to inflating an intravascular balloon. When the device is “relaxed” to allow more IVC flow-, the balloon or snare reduced the amount of external compression applied allowing for more venous return to the heart.

[0060] In this embodiment, the control mechanisms remain the same, IVC pulse wave doppler, aortic continuous / pulse wave doppler, pressure sensors, waveform analysis, patient weight, volume analysis, EKG, accelerometer, and gyroscope. However, because this device can require surgical implantation, this allows the components to be separated out from a single intravascular catheter. This reduces the mechanical complexity of the device and alsoallows the doppler ultrasound crystals to be placed directly onto the IVC and aorta to improve the reliability of their signals.

[0061] FIGS. 5 A-5B feature the following:1. IVC2. Renal Vein3. Aorta4. Renal Artery5. Iliac Artery6. Iliac Vein7. Extravascular Compression Device8. Extravascular Pulse Wave Doppler Device on IV C9. Extravascular Continuous / Pulse Wave Doppler Device on Aorta10. Control mechanisms / pumps / software / EKG / accelerometer / gyroscope / battery implanted into flank.

[0062] FIGS. 6A-6D feature the following:1. IVC (decompressed vs. compressed)2. Aorta3. Vertebral Body4. Frame of Compressive Device5. Inflatable portion of compressive device (deflated vs. inflated)

[0063] FIGS. 7A-7B feature the following:1. IVC (decompressed vs. compressed)2. Aorta3. Vertebral Body4. Snare encircling IVC (Relaxed vs. applying compression)

[0064] FIGS. 8A-8B feature the following:1. IVC2. Renal Vein3. Aorta4. Renal Artery5. Iliac Artery6. Iliac Vein7. Extravascular Compression Device8. Extravascular Pulse Wave Doppler Device on IVC9. Extravascular Continuous / Pulse Wave Doppler Device on Aorta10. Vertebral Body

[0065] FIGS. 9A-9D illustrate wholly intravascular or remote components for the device. Nothing permanently crosses a vascular wall. All components are either integral to an intravascular flow restriction device or exert effect data wirelessly. The device can be inactive or active. For example, balloon compression can create shape change that causes more flow restriction. This can negate a need for extravascular fluid or gas reservoir and transmission conduit. FIGS. 9A features device 10 contained within the inferior vena cava 12 and having a wireless control unit 40 and either implanted or external Doppler or pressure sensors 50. Device 10 shows a flow restriction mechanism or balloon 24 in inflated state. Stabilization hooks or struts 30 hold device 10 in place. Control unit 40 functions as described to take input from sensors and other sources. FIG. 9B features a coronal view of the device, depicting a compresson mechanism 80 that can activate flow restriction mechanism 24. FIG. 9C features an axial view of device 10 with flow restriction mechanism or balloon 24 an inactive state, showing device 10 held by struts 30 in the inferior vena cava 12. FIG. 9D features an axial view of device 10 with flow restriction mechanism or balloon 24 an active state in the inferior vena cava 12.

[0066] It should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific implementations described above. The specific implementations described above are disclosed as examples only.

Claims

CLAIMSWhat is claimed is:

1. A device comprising: a catheter or implanted device having a tip configured to be located within the distal IVC, between the confluence of the common iliac veins and the testicular / ovarian veins; and a flow restriction mechanism at or near the tip of the catheter or implanted device configured to be inflated with fluid or gas. and deflated by a control unit in order to optimize cardiac preload and cardiac output.

2. The device of claim 1, wherein the flow restriction mechanism includes a retrieveable and adjustable structure.

3. The device of claim 1, wherein the catheter tip or implanted device contains piezoelectric crystals or one or more pressure sensors to sample IVC and arterial blood flows or pressures as feedback mechanisms to determine optimal flow restriction.

4. The device of claim 1, further comprising piezoelectric crystals or one or more pressure sensors to estimate preload and cardiac output is configured to be surgically implanted into the adventitia of the IVC and aorta to sample flow patterns.

5. The devices of claim 1, further comprising a combination of accelerometers and gyroscopes located within the device that are configured to relay body position in space including supine, sitting, or standing, and a spectrum of activity levels, including still, low- level, or high-level activity, in real-time.

6. The device of claim 1, futher comprising an EKG which determines heart rate and heart rate variability to aid in the determination of a physiologic state requiring increased venous return.

7. The device of claim 1, wherein the catheter or a retrieveable strut system of the device has a surface compostition, both in terms of materials and shape, configured to mitigate the risk of thrombosis or fibrosis on a foreign device located in the blood stream or body cavity.

8. The device of claim 1, wherein the balloon or other flow restrictive mechanism is completely intravascular and stabilized with a set of radially expanding struts.

9. A method comprising controlling blood flow and limiting negative sequelae of the device via activation / inactivation patterns in a subject using the device of any one of claims 1-8.

10. A device comprising: a compressive device located adjacent to the extravascular distal IVC, between the confluence of the common iliac veins and the testicular / ovarian veins or another major venous structure; and a compressive mechanism configured to reduce the cross-sectional area of the IVC or other large venous structure when activated in order to optimize cardiac preload and cardiac output.

11. The device of claim 10, wherein the compressive device includes piezoelectric crystals, pressure sensors, volume analysis, weight, or waveform analysis to sample IVC and arterial blood flows, pressures, or other variables as feedback mechanisms to determine optimal balloon size.

12. The device of claim 10, further comprising piezoelectric crystals, pressure sensors, or other sensors essential to the function of the device to estimate preload, cardiac output, and optimal device activation patterns are surgically implanted into the adventitia of the IVC and aorta to sample flow patterns.

13. The device of claim 10, further comprising a combination of accelerometers and gyroscopes located within the device that are configured to relay body position in space including supine, sitting, standing, and a spectrum of activity levels including still, low-level, high-level activity in real-time.

14. The device of claim 10, futher comprising an EKG which can determine heart rate and heart rate variability to aid in the determination of a physiologic state requiring increased venous return (such as exercise).

15. The device of claim 10, wherein the compressive device has a surface compostition, both in terms of materials and shape, configured to mitigate the risk of thrombosis or fibrosis on a foreign device located in the blood stream or body cavity.

16. A method comprising controlling blood flow and limiting negative sequelae of the device via activation / inactivation patterns in a subject using the device of any one of claims

Images