Chronic heart failure device

Abstract

An apparatus includes: a catheter or implantable device having a tip configured to be located within a distal inferior vena cava (IVC), between the confluence of the common iliac veins and the testicular / ovarian vein; and a flow-limiting mechanism located at or near the tip of the catheter or implantable device, configured to be inflated with fluid or gas and deflated by a control unit to optimize cardiac preload and cardiac output.

Description

[0001] Priority Statement

[0002] 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 which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a device for treating chronic heart failure. Background Technology

[0004] Many symptoms and sequelae of heart failure are mediated by increased volume and pressure within the cardiac and venous systems. These lead to cardiac remodeling and progressive worsening of heart failure, while elevated venous pressure causes tachypnea via elevated pulmonary artery pressure, liver dysfunction via hepatic venous congestion, renal dysfunction via renal venous congestion, and numerous other problems. Heart failure patients are one of the leading sources of hospitalizations and are frequently readmitted due to acute exacerbations, placing a significant personnel and cost burden on hospital systems. Currently, there are no commercially available devices for managing preload in heart failure patients, but several are under development, including devices from preCARDIA, Doraya, and Venodynamics. However, all of these systems are designed for use during hospitalization. A functional preload management device, if applicable to outpatient management, could potentially reduce length of hospital stays and decrease admission frequency. Summary of the Invention

[0005] This summary presents some concepts in a simplified form, which will be further described in the detailed embodiments below. This summary is neither intended to identify key or essential features of the claimed subject matter nor to limit its scope.

[0006] In one aspect, a device may include a catheter or implantable 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 vein; and a flow-limiting mechanism, such as a balloon, at or near the tip of the catheter or implantable device, configured to be inflated with fluid or gas and deflated by a control unit to optimize cardiac preload and cardiac output.

[0007] On the other hand, a device may include a compression device located near the distal extravascular IVC, between the confluence of the common iliac vein and the testicular / ovarian vein or other major venous structures; and a compression mechanism (e.g., a balloon, a drawstring or snare, or other structure) configured to reduce the cross-sectional area of ​​the IVC or other major venous structures upon activation to optimize cardiac preload and cardiac output.

[0008] In another implementation, as an alternative to intravascular catheter-based balloon-based preload modulation, an implantable extravascular device, such as a balloon or drawstring / lasso, can be placed between the common iliac vein confluence and the testicular / ovarian vein along the IVC, or around other feasible vascular structures. Activation of this device can reduce the cross-sectional area of ​​the IVC or other large veins, thereby altering venous hemodynamics and allowing for optimization of cardiac preload.

[0009] In another embodiment, the device may include a retrievable and adjustable flow-limiting mechanism, such as a balloon, valve, or other structure. The device may be located in a distal IVC as described above. In this embodiment, the fixation mechanism may include radially expanding struts that stabilize the device in a preferred position. This fixation mechanism may be analogous to an IVC filter inserted for deep vein thrombosis (DVT). An important aspect of this embodiment is that the device can be designed for easy retrieval via a percutaneous mechanism, and all components of the flow-limiting mechanism are intravascular components, while all necessary extravascular components perform their functions wirelessly.

[0010] In some embodiments, the device may include a catheter tip containing a piezoelectric crystal or pressure sensor for sampling IVC and aortic blood flow as a feedback mechanism to determine optimal flow restriction. Flow restriction can be adjusted, for example, by changing the balloon size. The sensor may also include volumetric or waveform analysis to estimate changes in preload and cardiac output.

[0011] In some implementations, the compression device may include a piezoelectric crystal, pressure sensor, volumetric analysis, weight, or waveform analysis to sample IVC and arterial blood flow, pressure, or other variables as a feedback mechanism to determine the amount of reduction in the cross-sectional area of ​​the IVC or other large venous structures. The reduction in cross-sectional area can be adjusted, for example, by changing the balloon size.

[0012] If the device does not include an intravascular piezoelectric crystal contained within the catheter, the device control mechanism may include a piezoelectric crystal or one or more pressure sensors placed outside the blood vessel, on the IVC and the adventitia of the aorta, for the purpose of sampling the velocity patterns of blood flow in the IVC and the aorta to determine the optimal reduction in the cross-sectional area of ​​the IVC (or other large veins).

[0013] In some implementations, the compression device includes a piezoelectric crystal, a pressure sensor, or other sensors critical to the device's function for estimating preload, cardiac output, and optimal device activation mode. These sensors are surgically implanted into the adventitia of the IVC and aorta to sample blood flow patterns.

[0014] In some embodiments, the device may include a combination of an accelerometer and a gyroscope located within the device, configured to transmit in real time the body’s position in space (e.g., supine, sitting, standing) and a range of activity levels (e.g., stationary, low level, high level of activity).

[0015] In some implementations, the device may include an electrocardiogram (EKG) that can determine heart rate and heart rate variability to help identify physiological states that require increased venous return, such as exercise.

[0016] In some implementations, the assessment of preload is not based on the Doppler waveform as described above, but may be based on other modes, including but not limited to direct venous pressure, pressure changes or gradients before and after the device, IVC volume, weight changes, or peripheral venous waveform analysis.

[0017] In some embodiments, the device may include a catheter or a retrievable support system having a surface composition (including both material and shape) configured to mitigate the risk of thrombosis on a foreign device located in the bloodstream.

[0018] In some implementations, the balloon or flow-limiting device can be entirely intravascular and stabilized by a set of radially expanding struts. These struts may resemble the stabilization mechanism of a DVT filter. In this variant, no part of the device penetrates the vessel wall. All necessary components are either part of an intravascular assembly or function via remote mechanisms.

[0019] In other implementations, the materials should be optimized to reduce fibrosis around foreign bodies implanted around vascular structures.

[0020] In some implementations, a method may include using the device described herein to control blood flow to a subject.

[0021] In some implementations, a method may include using the device described herein to control blood flow to a subject via an activation / deactivation mode and limit adverse sequelae of the device.

[0022] The following detailed description refers to the accompanying drawings, which form part of this application, and illustrates specific exemplary embodiments by way of illustration. Other embodiments may be made without departing from the scope of this disclosure. Attached Figure Description

[0023] Figure 1 This is a schematic side view of the device described in this article in its inflated state.

[0024] Figure 2 This is a schematic side view of the device described in this article in the venting state.

[0025] Figure 3 This is a schematic top view of the device described in this article in its inflated state.

[0026] Figure 4 This is a schematic top view of the device described in this article in the venting state.

[0027] Figure 5A-9D An implementation scheme of the extravascular device described herein is shown. Detailed Implementation

[0028] This concept is a device designed to improve the treatment of acute, chronic, or acute-chronic heart failure. As described below, managing venous blood volume or pressure can improve symptoms of heart failure and reduce the sequelae of acute or chronic disease. A device capable of redistributing venous blood from the proximal IVC and cardiac chambers to the lower extremity vascular beds or other peripheral vascular beds would reduce pressure in the pulmonary, hepatic, mesenteric, and renal vascular systems, where disease-related sequelae should be less prevalent. After implementation, the redistribution of blood flow should position the failing heart more favorably on the Frank-Starling curve and improve cardiac output. It should also improve organ perfusion and urine output by improving cardiac output and reducing venous congestion. A device can achieve this by balloon inflation or adjustable mechanical structures (wings / valve / channel / drawstring / snatch) that reduce flow through back pressure or turbulence. Furthermore, extravascular balloons, drawstrings, snatches, or other compression devices can reduce the cross-sectional area of ​​the IVC or other large veins and achieve similar changes in venous hemodynamics. These flow-modulating mechanisms should be modulated via a wired or wireless external controller and can be adjusted based on activity level, symptoms, or data on pressure, flow rate, volume, waveform morphology, or body weight that may be obtained from the device itself. The device may self-regulate based on this data via an implanted wired control mechanism. The device can be placed within or on the IVC, between the iliac vein confluence and the renal vein to avoid congestion of the renal, hepatic, or mesenteric vessels. It can also be placed around another major vascular structure if deemed appropriate. It should be implanted and retrieved via the femoral or internal jugular vein approach by an interventional radiologist or interventional cardiologist, or surgically implanted by a vascular surgeon or cardiothoracic surgeon.

[0029] The devices currently under development have design flaws that limit their application in treating heart failure on an outpatient or non-hospitalized basis. For example, the Cardioflowtech device is a proximal IVC device. The balloon appears to be positioned proximal to the renal vein. The Venodynamics device appears to be similarly positioned to our proposed device, but the presence of external catheters and control mechanisms makes it unsuitable for outpatient management. The preCARDIA device is a superior vena cava (SVC) positioning device that may cause venous congestion in the head, leading to reduced cerebral perfusion. This design may not alleviate venous congestion in the kidneys, liver, and intestines. By positioning the flow-limiting device at a more distal IVC location, between the iliac vein confluence that forms the IVC and the renal vein, the device described herein provides additional benefits that existing mechanical preload management attempts have failed to offer. By positioning the balloon at this location, it both increases cardiac output by optimizing cardiac preload and reduces venous congestion in vital organs such as the liver, kidneys, intestines, and brain. These combined benefits enhance perfusion to these vital organs by improving perfusion pressure in the capillary bed. This should reduce non-cardiac sequelae of heart failure, including chronic kidney disease, liver dysfunction or cirrhosis, cardio-gut syndrome, pulmonary hypertension, and cognitive decline due to insufficient cerebral perfusion. RevampMedical's Doraya catheter, a flow-changing device, has a similar placement to the device proposed in this application, but it lacks feedback mechanisms that contribute to improved safety, applicability to a wider patient population, and outpatient management of heart failure, which this device possesses. Other devices are primarily designed to increase cardiac output by optimizing cardiac preload, but they may have minimal or even detrimental effects on venous congestion in vital organs outside the heart. Another advantage of this location is the ease of sampling venous and arterial blood flow, pressure, and volume to manage device setup. The IVC and aorta are directly adjacent in this location, allowing for easy sampling of Doppler ultrasound signals from both the IVC and aorta to provide feedback on the effects of device setup, body position, and activity level. For extravascular implementations, the relative proximity of the flow modulator implantation site to the Doppler signal site makes surgical exposure easier than in more dispersed locations.

[0030] Aside from optimizing the location of the flow regulation mechanism, other devices employ overly simplistic control mechanisms unsuitable for outpatient management of chronic heart failure. The preload requirements of outpatient chronic heart failure patients are quite complex and constantly changing. The device described in this article, along with its unique control mechanism, provides a unique approach suitable for both inpatient and outpatient heart failure management. Demand assessment is performed using accelerometer and EKG monitoring. Body posture assessment related to preload requirements is performed using a combination of accelerometers and gyroscopes, which can distinguish between supine, sitting, and standing patients. Assessment of venous blood flow, pressure, volume, and waveform analysis can be performed via pulse-wave Doppler or other sensor technologies sampled within the IVC, and the device can determine the relationship between these blood flow and other data points and the cardiac cycle. Estimation and assessment of changes in cardiac output or systemic pressure are performed through continuous or pulse-wave Doppler sampling of the abdominal aorta, or through direct or indirect pressure measurements.

[0031] To mitigate the effects of redistributing blood volume to the lower extremities, the device can also perform periodic calibration procedures while the patient is supine. By performing this procedure (potentially through a series of flow restrictions followed by release and assessment of subsequent flow), the device can signal to the patient or their clinician that additional volume management strategies, such as dietary changes or adjustments to the diuretic regimen, are needed.

[0032] In addition, the activation and deactivation modes, timing and extent of the device can be optimized to save battery life, reduce the risk of patient falls or sudden changes in cardiac output, reduce the risk of device-related thrombosis, and reduce lower extremity edema.

[0033] Figure 1 A schematic side view of the device described herein in its inflated state is shown. Figure 1 A coronal view of device 10 within the distal inferior vena cava 12 is depicted, with the flow-limiting mechanism or balloon 24 in an inflated state. Catheter 20 includes a tip 22 and a flow-limiting mechanism 24 proximal to the tip 22. A stabilizing hook or strut 30 secures device 10 in place. Control unit 40 functions as described above, receiving input from sensors and other sources. The balloon, filled with fluid or gas, can be in a maximally inflated state surrounding the distal tip of the device. The flow-limiting mechanism, such as a balloon, can be a spherical balloon (e.g., as shown in the image). Figure 1 (As shown), it can also be elliptical. In other embodiments of the device, the balloon may not cover the device tip containing the ultrasound components. The distal tip of the device may contain pulsed wave and continuous wave Doppler devices (shaded area). The Doppler devices can be oriented in a variety of different ways to optimize meaningful data collection.

[0034] Figure 2 A schematic side view of the device described herein in the vented state is shown. Figure 2 A coronal view of the device within the distal inferior vena cava is depicted, with the balloon in a deflated state. Catheter 20 includes a tip 22 and a flow-limiting mechanism 24 (shown in a deflated state) adjacent to the tip 22. A stabilizing hook or strut 30 secures the device 10 in place. Control unit 40 functions as described above, receiving input from sensors and other sources. Device 10 may include a sensor 50, which may be a piezoelectric crystal, pressure sensor, pulsed wave Doppler, continuous wave Doppler, aortic velocity-time integral (VTI), or other sensing method. Catheter 20 may include a catheter 60 for delivering saline, electrical, ultrasound signals, or other external stimulation. A balloon filled with fluid or gas may be in a deflated state surrounding the distal end of the device. The flow-limiting mechanism, such as the balloon, may be a spherical balloon (e.g., as shown in the image). Figure 2 (As shown), it can also be elliptical. In other embodiments of the device, the balloon may not cover the tip of the device containing the ultrasound components.

[0035] Figure 3 A schematic top view of the device described herein in its inflated state is shown. Figure 3 An axial view of the device within the distal inferior vena cava is depicted, with the balloon inflated. The catheter 20 includes a tip 22 and a flow-limiting mechanism 24 (shown inflated) near the tip 22. A stabilizing hook or strut 30 secures the device 10 in place. The control unit 40 functions as described above, receiving input from sensors and other sources. The balloon, filled with fluid or gas, can be inflated to its maximum position around the distal tip of the device.

[0036] Figure 4 A schematic top view of the device described herein in the vented state is shown. Figure 4 An axial view of the device within the distal inferior vena cava is depicted, with the balloon in a deflated state. The catheter 20 includes a tip 22 and a flow-limiting mechanism 24 near the tip 22 (shown in the deflated state). A stabilizing hook or strut 30 secures the device 10 in place. The control unit 40 functions as described above, receiving input from sensors and other sources. A balloon filled with fluid or gas can be in a deflated state surrounding the distal tip of the device.

[0037] The device may include conduits for fluid / gas inflation and deflation flow limiting mechanisms or balloons. Flexible conduits can serve as fluid / gas conduits between the reservoir and the balloon, as a means of anchoring the device within the IVC, or as data transmission channels from Doppler components and other data sources such as EKG and gyroscope / accelerometers. In other embodiments, the fluid or gas reservoir for balloon inflation is entirely contained within the device or balloon, and as a change in balloon shape, appropriate pressure gradients or flow limiting across the device can be created while maintaining the same volume.

[0038] In some implementations, a series of hooks or struts can restrict movement of the device tip or the entire device within the IVC. In some variations, struts are the only fixation mechanism because no structure penetrates the vessel wall after implantation.

[0039] In some embodiments, the control unit may be implanted in the patient's lateral abdomen and includes a fluid / gas reservoir for the balloon, processing capabilities for data interpretation and decision-making, possible location of the EKG and gyroscope / accelerometer, Bluetooth / Wi-Fi functionality for patient and clinician access and device management, and a battery. In other embodiments, the control unit, including the aforementioned functions, may be completely wireless and non-implantable.

[0040] Anchoring mechanism and location of the device:

[0041] The device is anchored within the distal abdominal intravascular coagulation (IVC), located between the confluence of the common iliac veins and the junction of the IVC and the right testicular / ovarian veins (also distal to the renal veins). This allows the device to reduce venous pressure from critical organs (liver, kidneys, intestines) and redistribute that volume to less affected areas of the body (both lower extremities). This allows the device to improve organ perfusion by both optimizing preload to improve cardiac output and by reducing venous pressure to improve organ perfusion pressure (mean arterial pressure - venous pressure). This redistribution allows patients and their physicians to optimize diuretic therapy, improve diuretic performance, and modify the patient's diet to restore their volume status to a more appropriate level.

[0042] In one embodiment, the device is anchored in place by 4-6 radially self-expanding hooks (similar to IVC filters) to secure it to the inferior vena cava wall. Alternatively, the device may be secured by a cable connecting the balloon portion of the device to its subcutaneously implanted power source. This cable also contains a connection for the ultrasound device and a catheter for delivering saline solution between the inflatable balloon and the reservoir within the battery pack. However, in some embodiments, the sole fixation device may include a self-expanding strut.

[0043] Another embodiment of the device is a fully endovascular design, which combines a flow-limiting balloon or valve with a self-expanding strut for securing the device in place. This embodiment can be retrieved via a percutaneous mechanism. The device's control and power mechanisms can operate wirelessly.

[0044] In extravascular implementations, the flow regulation mechanism may be anchored next to or around the IVC, as described above, or located around another major vascular structure. The anchoring mechanism itself may be, but is not limited to, a plate and screw device that secures the device to the vertebral body, or any other fixation mechanism relative to adjacent structures.

[0045] The device described herein requires the use of various specialized materials to achieve the goal of safely and effectively optimizing patient cardiac preload over extended periods in an outpatient setting. The balloon inflation / deflation mechanism requires a driving fluid or liquid. Other systems typically use gases for this purpose—helium, carbon dioxide, or air—all of which may be suitable for this system, depending on the ultimately desired characteristics: effective balloon control over extended periods with minimal physiological consequences in the event of balloon rupture. Biocompatible fluids may also be used. While fluids are expected to have slower inflation / deflation times due to greater resistance, this may be less relevant as the frequency of balloon changes is expected to be lower than in competing systems. The system surface needs to be designed to limit the risk of blood clot formation. This can be achieved in several ways. First, the shape of the catheter and flow-limiting mechanisms (e.g., the balloon) can be designed to limit blood stagnation. This surface can be coated with a variety of materials to achieve a bioactive or bioinert coating, typically albumin, heparin, or other proprietary compounds. The surface can also be designed to promote endothelialization, providing a surface similar to that of one's own blood vessels. Inflation and deflation patterns can also be used to limit blood flow stagnation, thereby reducing the risk of thrombosis around the device. The housing containing the ultrasound components, drive wire, and any other input / output mechanisms needs to be a flexible and biocompatible polymer. Where the ultrasound beam is intended to be transmitted, the housing needs to allow the beam to efficiently pass through the housing into surrounding tissue and return without significant signal loss. Finally, the balloon itself needs to be made of a durable, flexible, and biocompatible material capable of limiting clot formation while withstanding repeated inflation / deflation cycles without rupture. Ideally, the balloon should also limit leakage of the drive fluid, so the system may not require frequent replenishment of the drive fluid. Another form of thrombosis prevention could be repositioning the device and its control mechanisms from the intravascular IVC to adjacent extravascular tissue, thereby eliminating contact between the foreign implanted material and proteins in the coagulation cascade. In this case, the material could be designed to limit the formation of scar tissue or fibrosis around the device and vein, preventing permanent blood flow restriction.

[0046] The device can be placed in the distal intravenous venous cavity (IVC) using the Seldinger technique. The femoral vein can be punctured with a needle. A guidewire is then inserted into the IVC. Once proper guidewire positioning is confirmed by ultrasound or fluoroscopy, a series of catheter dilations are performed, culminating in the insertion of the device along the guidewire. The final position of the distal IVC can be confirmed by fluoroscopy and, if possible, intravenous contrast. Appropriate Doppler signals will be confirmed in the IVC and aorta before allowing the radial dilation hooks to deploy. Device positioning is then stabilized using the radial dilation hooks. The proximal end of the device is then subcutaneously tunneled to the lateral abdomen, where it is connected to a control device containing a drive fluid reservoir, a CPU for interpreting input and determining appropriate balloon changes, an accelerometer / gyroscope unit, and ECG leads. This control device is also implanted subcutaneously in the lateral abdomen.

[0047] Alternatively, the device can be placed similarly to the variations described above, but all necessary components are intravascular. This variation may not require a connecting catheter that necessitates a tunneled lead. The fluid or gas used to change the balloon size can also be intravascular and self-contained. It can either contain the entire control mechanism or communicate with the control device via Wi-Fi, near-field communication, or Bluetooth.

[0048] In extravascular implementations, surgical rather than percutaneous placement may be used. This is likely accomplished through a Pfannenstiel incision in the lower abdomen, followed by dissection and movement of organs and blood vessels to expose the abdominal IVC, aorta, and lumbar spine, in order to secure the device and control mechanisms there.

[0049] Balloon design:

[0050] One hypothetical balloon shape could be a biocompatible spherical balloon containing saline or gas, located near or around the device tip within the IVC. The device tip contains key components for controlling balloon size by monitoring IVC and aortic blood flow: piezoelectric crystals or other modalities such as pressure sensors for transmitting and receiving pulsed and continuous-wave Doppler. Monitoring of IVC and aortic blood flow or pressure can be performed in real time. Aortic blood flow at the level of the abdominal aorta can be readily sampled from the device located distally within the IVC. By utilizing continuous or pulsed-wave Doppler from a set of piezoelectric crystals in the device tip, a trajectory of aortic blood flow velocity over time can be created. The integral of these curves, or velocity-time integral (VTI), corresponds to the column height of blood passing through the abdominal aorta with each heartbeat. The abdominal aortic VTI fluctuates proportionally to the VTI at the left ventricular outflow tract, thus providing an excellent surrogate indicator for monitoring the effect of balloon changes on cardiac output. Changes in the abdominal aortic VTI can then be used to optimize preload via the balloon mechanism. Pulse-wave Doppler sampling of IVC blood flow can indicate varying degrees of fluid volume overload. Essentially, the more severe the patient's volume overload, the farther the cardiac cycle's effect on venous blood flow will be observed from the right atrium, as a more congested venous system propagates fluid waves more effectively. IVC pulse-wave Doppler sampling can also be used in conjunction with gyroscopes and accelerometers to detect rapid changes in IVC venous blood flow caused by changes in body position. Alternatively, instead of using Doppler signals, direct or indirect pressure, volume, flow, patient weight, or waveform analysis measurements from the IVC and aorta can be used as useful alternative indicators to guide device management. Finally, IVC sampling will be used for periodic calibration protocols, in which IVC blood flow or pressure is sampled after a series of balloon inflation / deflation cycles. This allows patients and their clinicians to adjust diuretic therapy. To synthesize this data and determine appropriate management responses, the processing unit will be contained in a control unit located on the patient's lateral abdomen or a wireless remote controller. The processing unit will be able to interpret real-time data from pulsed and continuous wave Doppler, EKG, gyroscope / accelerometer, or any other relevant sensors to determine appropriate changes to the balloon size via the included pump and drive line connected to the balloon. The control unit can be accessed via a mobile app or a proprietary monitoring device supporting Bluetooth or Wi-Fi, allowing patients and their clinicians to monitor device functionality and make changes as needed. The device is anchored to the IVC via a self-expanding hook and possibly a tether that connects the balloon and sensors housed in the device tip to the control unit and reservoir. The balloon size can be adjusted by injecting or withdrawing saline or gas from the reservoir housed in the control unit. The balloon shape is likely to be spherical or elliptical. However, the balloon can take various forms depending on its performance in maintaining laminar rather than turbulent flow. Laminar flow can be facilitated by several mechanisms.The balloon shape is designed to minimize the angle of incidence when blood contacts the balloon, thus achieving a more laminar flow pattern. This is achieved by using an elliptical rather than a spherical balloon shape. The catheter surface is also designed to reduce drag. This is achieved by using materials that reduce the buildup of proteins and other substances that increase surface irregularities. By minimizing drag, fewer eddies are formed, thus reducing turbulence. Ideally, a shape that maintains a degree of laminar flow in all inflation / deflation states should be chosen, as this minimizes the risk of thrombosis. See Appendix. Figure 1-4 .

[0051] In an extravascular implementation, a fully or partially circumferential compression device, likely a balloon or drawstring, can be secured adjacent to or around the abdominal IVC, between the iliac vein confluence and the renal vein. Upon activation, the compression device can engage with the outer surface of the IVC to reduce the cross-sectional area of ​​the vessel at that location. This allows for optimization of cardiac preload as described above. The surface of such an implantable device can be designed to limit the formation of tissue fibrosis that could lead to permanent restriction of venous blood flow.

[0052] Multi-fork feedback mechanism for controlling preload:

[0053] Pulsed-wave Doppler along IVC blood flow orientation to determine preload (sampling location is flexible): The proposed device utilizes a set of piezoelectric crystals whose ultrasound beams are oriented along the IVC axis. These allow the device to measure the blood flow velocity and direction at specific points within the IVC. Different levels of fluid balance (hypovolemia, normal volume, mild volume overload, and severe volume overload) exhibit different IVC blood flow patterns at different points within the IVC. Essentially, the more severe the patient's volume overload, the further away from the right atrium the cardiac cycle's influence on venous blood flow will be observed, as a more congested venous system propagates fluid waves more efficiently. These blood flow patterns are correlated with the cardiac cycle, thus allowing a single-lead EKG to be placed within the control unit, on the patient, or at another location within the body to better characterize the IVC blood flow patterns. Based on the location where sampling occurs, these blood flow patterns can then be used as input to train AI-driven algorithms for optimal preload management by determining the optimal balloon size or the optimal amount of reduction in cross-sectional area through external compression. Variations in blood flow patterns can also be observed in changes in body position and activity level, which can further optimize algorithmic control of preload. These blood flow patterns can be sampled and interpreted in real time to rapidly adjust balloon size, thereby maintaining adequate venous return and cardiac output. Pulse-wave Doppler sampling of IVC blood flow can indicate varying degrees of volume overload. IVC pulse-wave Doppler sampling can also be used in conjunction with gyroscopes and accelerometers to detect rapid changes in IVC venous blood flow caused by changes in body position. Finally, IVC sampling will be used for periodic calibration protocols in which IVC blood flow is sampled after a series of balloon inflation / deflation cycles. This allows patients and their clinicians to adjust diuretic therapy. To synthesize this data and determine an appropriate management response, a processing unit will be included in a control unit located on the patient's lateral abdomen. This processing unit will be able to interpret real-time data from pulse-wave and continuous-wave Doppler, EKG, and gyroscope / accelerometer measurements to determine appropriate changes to balloon size via the included pump and drive lines connected to the balloon. This control unit can be accessed via a mobile app or a proprietary monitoring device supporting Bluetooth or Wi-Fi, allowing patients and their clinicians to monitor device functionality, patient fluid balance measurements, and make device changes as needed. Alternatively, patient preload can be assessed using pressure sensors within the device that measure venous pressure before and after the device. These can be correlated with surrogate indicators such as systemic blood pressure or cardiac output to determine individual preload requirements. Other methods of assessing preload include volumetric measurements, flow measurements, patient weight, and peripheral or central venous waveform analysis, all of which can be used within the device to determine individual preload requirements.

[0054] Continuous or pulsed wave Doppler ultrasound along the direction of blood flow in the abdominal aorta to determine its effect on cardiac output:

[0055] By combining monitoring pressure differential, IVC blood flow velocity, waveform, or other preload assessments, our device utilizes a second set of piezoelectric crystals whose beams are oriented along the blood flow axis of the abdominal aorta, which is adjacent to the IVC where our device is located. This makes the IVC an ideal placement location for the device. Using continuous or pulsed wave Doppler at this location, the device allows for real-time monitoring of blood flow velocity in the aorta throughout the entire cardiac cycle. Calculating the area under the velocity-time curve allows the device to monitor the height (or distance) of the blood column passing through the abdominal aorta with each heartbeat. This velocity-time integral (VTI) varies with preload, myocardial contractility, and afterload. The abdominal aortic VTI fluctuates proportionally to the VTI at the left ventricular outflow tract (the last segment of the heart structure blood passes through before leaving the heart via the aortic valve), thus providing an excellent surrogate indicator for monitoring the effect of balloon changes on cardiac output. Changes in the abdominal aortic VTI can then be used to optimize preload and cardiac output via balloon or flow-limiting mechanisms. Alternatively, other surrogate measures of cardiac output, such as systemic blood pressure, VTI at other sites, or biological response mechanisms, can be used in combination with other methods to estimate the device’s effect on cardiac output.

[0056] In addition to monitoring the effect of the balloon on cardiac output (by monitoring the time integral of the abdominal aortic velocity), this aspect of the device allows AI-driven algorithms to monitor the need for “demand” patterns. Since the abdominal aortic VTI fluctuates with changes in myocardial contractility, heart rate, and cardiac preload, its measurement can help identify states of high physiological metabolic demand. Essentially, increases in heart rate and VTI generally correspond to high-demand physiological states, such as exercise. When a patient begins physical activity, their heart rate and myocardial contractility should increase, resulting in a higher VTI and a higher heart rate, both monitored by the Doppler function of our device. When this set of parameters is encountered, our device is then able to adjust the balloon size to allow more preload to flow back to the heart to facilitate exercise. To distinguish these states of high metabolic demand from other causes of increased heart rate, such as increased volume overload, arrhythmias, or myocardial ischemia, models need to be created to train the decision-making mechanism regarding appropriate balloon inflation states. Different patients require different preload levels to maintain optimal cardiac output because they require different filling pressures to achieve different end-diastolic volumes. Therefore, strictly using algorithmic methods may not be enough; decision models may need to be trained using individual patient data to achieve optimal results through optimal cardiac filling.

[0057] Gyroscope / Accelerometer: As a third part of the feedback mechanism, a gyroscope and accelerometer can be included within the battery / control / storage unit, enabling the device to determine changes in body position and activity level. The placement of this system should be able to distinguish various patient postures, whether supine, sitting, or standing. Therefore, multiple sets of sensors may be required to differentiate certain body postures. Preferably, the system can be integrated into the device to minimize potential connectivity issues associated with acquiring this data from external devices. One of the highest-risk periods for decreased cardiac output due to low preload (which can lead to falls) is when the patient moves relatively quickly from a supine position to a standing position, resulting in a decrease in preload. The gyroscope / accelerometer should provide immediate feedback to our control mechanism to adjust balloon size. If the control unit relies on a declining abdominal aortic VTI measurement (or other surrogate indicators of cardiac output), it may lead to management delays or an increased risk of falls, as declining cardiac output is a “late” indicator of preload reduction. In addition to moving between supine and standing positions, the accelerometer can also aid the algorithm's "demand" function, helping to identify increased physical activity or other physiological states that require higher venous return. In response to these states requiring more venous return, the algorithm should reduce the balloon size to allow more blood flow back to the heart.

[0058] Electrocardiogram (EKG): The device will include a single-lead EKG to serve multiple functions. By detecting changes in heart rate and heart rate variability, it helps detect algorithms that detect increased physiological demands for greater venous return. By identifying various points in the cardiac cycle (atrial depolarization, ventricular depolarization, ventricular repolarization), the EKG works in conjunction with pulse-wave Doppler of the venous system to detect varying degrees of volume overload.

[0059] This system can control venous return via an IVC balloon or compression mechanism to optimize cardiac preload, filling pressure, and cardiac output, thereby providing inpatient or outpatient management of acute, chronic, or acute-chronic heart failure.

[0060] In some implementations, algorithms and models can determine optimal balloon size or compression to optimize cardiac preload. The algorithm can also be used to determine optimal inflation and deflation patterns to prevent thrombosis, optimize diuretic management, reduce patient falls, and minimize sequelae of device use, such as reducing venous remodeling stimulation that could limit the effective duration of treatment. The algorithm can utilize data generated by inherent pulse and continuous wave Doppler systems, accelerometers, gyroscopes, pressure sensors, volumetric analysis, patient weight, and / or EKG to determine whether more or less venous return is needed at any given time, and then use a pump to inflate or deflate the IVC balloon or reduce compression. Because different patients have different inflation requirements, individual patient data can be used post-implantation to train AI-driven decision-making models.

[0061] The calibration procedure can determine when lower extremity venous pressure and fluid levels increase to a level requiring a change in medication therapy, such as altering diuretic treatment, to optimize the patient's fluid balance.

[0062] In some implementations, the demand function associated with the device can determine physiological states that require higher venous return and adjust the balloon size or compression accordingly.

[0063] Extravascular IVC compression device

[0064] In another embodiment of the device, the IVC blood flow modulation method shifts from an intravascular device to an extravascular IVC compression mechanism. This mechanism can be, but is not limited to, an extravascular balloon or snare that completely or partially surrounds the distal IVC located in a similar position as described above. When this mechanism is activated, it causes external compression of the IVC, resulting in reduced blood flow, similar to the inflation of an intravascular balloon. When the device “relaxes” to allow more IVC blood flow, the balloon or snare reduces the amount of external compression applied, allowing more venous return to the heart.

[0065] In this implementation, the control mechanisms remain unchanged: IVC pulsed-wave Doppler, aortic continuous / pulsed-wave Doppler, pressure sensor, waveform analysis, patient weight, volumetric analysis, EKG, accelerometer, and gyroscope. However, since the device may require surgical implantation, this allows the components to be separated from a single intravascular catheter. This reduces the mechanical complexity of the device and also allows the Doppler ultrasound crystal to be placed directly on the IVC and aorta to improve the reliability of its signal.

[0066] Figures 5A-5B The following content was displayed:

[0067] 1. IVC

[0068] 2. Renal vein

[0069] 3. Aorta

[0070] 4. Renal artery

[0071] 5. Iliac artery

[0072] 6. Iliac vein

[0073] 7. External vascular compression device

[0074] 8. Extravascular pulse-wave Doppler device on IVC

[0075] 9. Extravascular continuous / pulse-wave Doppler device on the aorta

[0076] 10. Control mechanism / pump / software / EKG / accelerometer / gyroscope / battery implanted in the lateral abdomen.

[0077] Figures 6A-6D The following content was displayed:

[0078] 1. IVC (Uncompressed vs. Compressed)

[0079] 2. Aorta

[0080] 3. Vertebrae

[0081] 4. Compression device frame

[0082] 5. The inflatable part of the compression device (uninflated vs. inflated)

[0083] Figures 7A-7B The following content was displayed:

[0084] 1. IVC (Uncompressed vs. Compressed)

[0085] 2. Aorta

[0086] 3. Vertebrae

[0087] 4. The snare around the IVC (relaxation vs. applying pressure)

[0088] Figures 8A-8B The following content was displayed:

[0089] 1. IVC

[0090] 2. Renal vein

[0091] 3. Aorta

[0092] 4. Renal artery

[0093] 5. Iliac artery

[0094] 6. Iliac vein

[0095] 7. External vascular compression device

[0096] 8. Extravascular pulse-wave Doppler device on IVC

[0097] 9. Extravascular continuous / pulse-wave Doppler device on the aorta

[0098] 10. Vertebrae

[0099] Figures 9A-9DThe device is demonstrated as a completely intravascular or remote assembly. No component permanently penetrates the vessel wall. All components are either integral parts of the intravascular flow-limiting device or transmit effect data wirelessly. The device can be in an inactive or active state. For example, balloon compression can produce a shape change, resulting in greater flow restriction. This can eliminate the need for extravascular fluid or gas reservoirs and delivery catheters. Figure 9A The device 10 is shown located within the inferior vena cava 12 and includes a wireless control unit 40 and an implantable or external Doppler or pressure sensor 50. The device 10 shows the flow-limiting mechanism or balloon 24 in an inflated state. A stabilizing hook or support 30 secures the device 10 in place. The control unit 40 functions as described above, receiving input from sensors and other sources. Figure 9B A coronal view of the device is shown, depicting a compression mechanism 80 that can activate the flow restriction mechanism 24. Figure 9C An axial view of the device 10 is shown, with the flow limiting mechanism or balloon 24 in an inactive state, and the device 10 is shown to be secured within the inferior vena cava 12 by a strut 30. Figure 9D An axial view of the device 10 is shown, with the flow limiting mechanism or balloon 24 in an activated state within the inferior vena cava 12.

[0100] It should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific embodiments described above. The specific embodiments described above are disclosed as examples only.

Claims

1. An apparatus comprising: A catheter or implantable device having a tip configured to be located in the distal inferior vena cava (IVC), between the confluence of the common iliac veins and the testicular / ovarian vein; as well as A flow-limiting mechanism, located at or near the tip of the catheter or implanted device, is configured to be filled with fluid or gas and deflated by a control unit to optimize cardiac preload and cardiac output.

2. The apparatus of claim 1, wherein the flow limiting mechanism comprises a recyclable and adjustable structure.

3. The device of claim 1, wherein the catheter tip or implanted device comprises a piezoelectric crystal or one or more pressure sensors for sampling IVC and arterial blood flow or pressure as a feedback mechanism to determine optimal flow restriction.

4. The device of claim 1 further includes a piezoelectric crystal or one or more pressure sensors for estimating preload and cardiac output, which are configured to be surgically implanted into the adventitia of the IVC and the aorta to sample blood flow patterns.

5. The apparatus of claim 1, further comprising a combination of an accelerometer and a gyroscope located within the apparatus, configured to transmit in real time the position of the body in space, including supine, sitting, or standing positions, and a range of activity levels, including stationary, low-level, or high-level activity.

6. The device of claim 1 further includes an electrocardiogram (EKG) which determines heart rate and heart rate variability to help determine physiological states requiring increased venous return.

7. The device of claim 1, wherein the catheter or the retrievable support system of the device has a surface composition, including both material and shape aspects, configured to mitigate the risk of thrombosis or fibrosis on foreign devices located in the bloodstream or body cavity.

8. The device of claim 1, wherein the balloon or other flow-limiting mechanism is entirely intravascular and stabilized by a set of radially expanding struts.

9. A method comprising using the device of any one of claims 1-8 to control blood flow to a subject via an activation / deactivation mode and limit adverse sequelae of the device.

10. An apparatus comprising: The compression device is located near the distal extravascular IVC, between the confluence of the common iliac vein and the testicular / ovarian vein or other major venous structures; as well as The compression mechanism is configured to reduce the cross-sectional area of ​​the IVC or other large venous structures when activated to optimize cardiac preload and cardiac output.

11. The device of claim 10, wherein the compression device comprises a piezoelectric crystal, a pressure sensor, volumetric analysis, weight or waveform analysis for sampling IVC and arterial blood flow, pressure or other variables as a feedback mechanism to determine the optimal balloon size.

12. The device of claim 10 further includes a piezoelectric crystal, a pressure sensor, or other sensors essential to the function of the device for estimating preload, cardiac output, and optimal device activation mode, which are surgically implanted in the adventitia of the IVC and the aorta to sample blood flow patterns.

13. The apparatus of claim 10, further comprising a combination of an accelerometer and a gyroscope located within the apparatus, configured to transmit in real time the position of the body in space, including supine, sitting, and standing positions, and a range of activity levels, including stationary, low-level, and high-level activities.

14. The device of claim 10 further includes an electrocardiogram (EKG) capable of determining heart rate and heart rate variability to help identify physiological states requiring increased venous return (such as exercise).

15. The device of claim 10, wherein the compression device has a surface composition, including both material and shape aspects, configured to mitigate the risk of thrombosis or fibrosis on a foreign device located in the bloodstream or body cavity.

16. A method comprising using the device of any one of claims 10-13 to control blood flow to a subject and limit adverse sequelae of the device via an activation / deactivation mode.

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