System for selectively occluding peripheral vein vascular system to mitigate cardiac burden

Abstract

Systems and methods are provided for intermittently occluding a venous vascular system of a patient to mitigate cardiac burden while increasing cardiac output and improving perfusion of the patient's heart. The system may include first and second balloon catheters selectively actuatable to intermittently occlude first and second veins to increase venous vascular resistance, respectively, of lower and upper limbs of the patient, thereby selectively reducing arterial blood flow to the lower and upper limbs, at the same time, the arterial vascular resistance of the heart and central organs of the patient is maintained and perfusion to the heart and central organs of the patient is increased.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 365,941, filed on June 6, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to reducing cardiac workload to improve cardiac function in patients with heart failure, including patients with reduced ejection fraction, and to treat pulmonary hypertension. Background Art

[0004] Heart failure is the leading cause of mortality worldwide. Heart failure often leads to multiple long-term hospitalizations, especially in the advanced stages of the disease. Without a heart transplant, the long-term prognosis for these patients is dismal, and medical approaches are only palliative. Therefore, there are very few effective treatments to slow or reverse the progression of this disease.

[0005] Heart failure can be caused by any of a variety of initiating events. Heart failure can occur due to ischemic heart disease, hypertension, valvular heart disease, infection, inherited cardiomyopathy, pulmonary hypertension, or under conditions of metabolic stress (including pregnancy). Heart failure can also occur without a clear cause - also called idiopathic cardiomyopathy. The term heart failure encompasses left ventricular, right ventricular, or biventricular failure.

[0006] Although the heart can usually respond successfully to the increased workload caused by hypertension or loss of contractile tissue at first, over time, this pressure triggers compensatory myocardial cell hypertrophy and ventricular wall remodeling. Specifically, in the next few months after the initial heart injury, the damaged part of the heart will usually begin to remodel because the heart strives to continue pumping blood when the muscle mass is reduced or the contractility is reduced. This often leads to excessive work of the myocardium, causing the myocardium in the damaged area to gradually become thinner, enlarged and further overloaded. At the same time, the ejection fraction of the damaged ventricle decreases, resulting in a lower cardiac output and a higher average pressure and volume in the ventricle throughout the cardiac cycle, which is a characteristic of heart failure. Needless to say, once the patient's heart enters this gradually self-perpetuating spiral decline, the patient's quality of life is severely affected, and the risk of morbidity soars. Depending on several factors, including the patient's previous physical condition, age, gender and lifestyle, the patient may experience one or several hospitalizations, causing considerable costs to the patient and the social medical security system until the patient dies of cardiac arrest or any of several comorbidities, including stroke, renal failure, liver failure or pulmonary hypertension.

[0007] Pharmaceutical approaches are available as palliatives to alleviate the symptoms of heart failure, but there are no pharmaceutical approaches to prevent or reverse heart failure. Furthermore, existing pharmaceutical approaches are systemic in nature and do not address the local effects of remodeling on cardiac structure. Therefore, it would be desirable to provide systems and methods for treating heart failure that can prevent and, more preferably, reverse cardiac remodeling that leads to the cascade of effects associated with this disease.

[0008] Pulmonary hypertension (PH) is also a major cause of morbidity and mortality worldwide. Although heart failure is a common cause of pulmonary hypertension, as mentioned above, pulmonary hypertension can also be caused by primary lung disease. Nowadays, drug therapy can reduce pulmonary artery systolic pressure (PASP) and improve the symptoms and ultimately survival of patients with pulmonary hypertension. However, drug therapy has disadvantages, such as cost and side effects. Summary of the invention

[0009] The present disclosure overcomes the shortcomings of previously known systems and methods by providing a system for reducing the burden on a patient's heart to improve cardiac performance. The system may include: a first flow restriction element that can be selectively actuated to occlude a first vein in fluid communication with a first limb of the patient; a second flow restriction element that can be selectively actuated to occlude a second vein in fluid communication with a second limb of the patient; and a controller that is operably coupled to the first flow restriction element and the second flow restriction element. The controller can be programmed to expand the first and / or second flow restriction elements according to a predetermined actuation scheme to selectively occlude the first and / or second veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

[0010] In some embodiments, the first vein may be a contralateral crotch vein, and the second vein may be an ipsilateral crotch vein. The system may further include a third flow restriction element operably coupled to the controller, the third flow restriction element being selectively actuable to occlude the patient's superior vena cava (SVC). Thus, the controller may be programmed to expand the third flow restriction element according to a second predetermined actuation scheme to occlude the SVC and reduce cardiac preload. The system may further include a mechanical circulatory support (MCS) device.

[0011] The system may further include: a third flow restriction element operably coupled to the controller, the third flow restriction element selectively actuable to occlude the contralateral subclavian vein of the patient; and a fourth flow restriction element operably coupled to the controller, the fourth flow restriction element selectively actuable to occlude the ipsilateral subclavian vein of the patient. Thus, the controller may be programmed to expand the third and / or fourth flow restriction elements according to a second predetermined actuation scheme to selectively occlude the contralateral and / or ipsilateral subclavian veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

[0012] The system may further include a fifth flow restriction element operably coupled to the controller, the fifth flow restriction element being selectively actuable to occlude the superior vena cava (SVC) of the patient. Thus, the controller is configured to expand the fifth flow restriction element according to a third predetermined actuation scheme to occlude the SVC and reduce cardiac preload. The system may further include a catheter operably coupled to the controller, wherein the first flow restriction element and the second flow restriction element are disposed on a distal region of the catheter.

[0013] In some embodiments, the first vein may be the superior vena cava (SVC), and the second vein may be the inferior vena cava (IVC). Thus, the system may include a first catheter operably coupled to the controller and a second catheter operably coupled to the controller, wherein the first flow restriction element is disposed on a distal region of the first catheter, and the second flow restriction element is disposed on a distal region of the second catheter. The system may further include a mechanical circulatory support (MCS) device.

[0014] Furthermore, the predetermined actuation scheme may be programmed to: expand only the first flow restriction element for a first time period; expand the first flow restriction element and the second flow restriction element for a second time period after the first time period; expand only the second flow restriction element for a third time period after the second time period; and expand the first flow restriction element and the second flow restriction element for a fourth time period after the third time period. Thus, the predetermined actuation scheme may be programmed to occlude at least 70% of the first vein and the second vein during a treatment period. The predetermined actuation scheme may be programmed in the controller so that the first flow restriction element or the second flow restriction element or both remain occluded throughout a treatment session. Each occlusion period during a treatment session may be at least one minute.

[0015] The system may further include one or more sensors that can measure one or more parameters and generate one or more signals indicative of the one or more measured parameters. For example, a first sensor of the one or more sensors can be positioned proximate to the first flow restriction element, and a second sensor of the one or more sensors can be positioned proximate to the second flow restriction element. Additionally, the controller can be programmed to adjust the predetermined actuation scheme to selectively occlude the first and / or second vein in response to the one or more signals indicative of the one or more measured parameters.

[0016] According to another aspect of the present disclosure, a method for reducing the burden on a patient's heart to improve cardiac performance is provided. The method may include: positioning a first flow restriction element in a first vein in fluid communication with a first limb of the patient; positioning a second flow restriction element in a second vein in fluid communication with a second limb of the patient; and expanding the first and / or second flow restriction elements according to a predetermined actuation scheme to selectively occlude the first and / or second veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing arterial vascular resistance of the patient's limbs while maintaining arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs. For example, expanding the first and / or second flow restriction elements according to the predetermined actuation scheme may maintain occlusion of the first flow restriction element or the second flow restriction element or both throughout the course of treatment.

[0017] In some embodiments, positioning the first flow restriction element within the first vein of the patient may include positioning the first flow restriction element within the contralateral crotch vein of the patient, and positioning the second flow restriction element within the second vein of the patient may include positioning the second flow restriction element within the ipsilateral crotch vein of the patient. The method may further include: positioning a third flow restriction element within the contralateral subclavian vein of the patient; positioning a fourth flow restriction element within the ipsilateral subclavian vein of the patient; and inflating the third and / or fourth flow restriction elements according to a second predetermined actuation scheme to selectively occlude the contralateral and / or ipsilateral subclavian veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing arterial vascular resistance of the patient's limbs while maintaining arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

[0018] Alternatively, the method may include: positioning a third flow-restricting element within the superior vena cava of the patient; and intermittently actuating the third flow-restricting element according to a second predetermined actuation scheme to occlude the SVC and reduce cardiac preload. The method may further include: positioning a mechanical circulatory support (MCS) device within the heart of the patient; and actuating the MCS device. In some embodiments, positioning the first flow-restricting element within the first vein of the patient includes positioning the first flow-restricting element within the superior vena cava (SVC) of the patient, and positioning the second flow-restricting element within the second vein of the patient includes positioning the second flow-restricting element within the inferior vena cava (IVC) of the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A An exemplary system for improving cardiac function incorporating a dual balloon catheter constructed according to the principles of the present disclosure is described.

[0020] Figure 1B yes Figure 1A A cross-sectional view of a catheter of the system.

[0021] Figure 2 Description can be included in Figure 1A Some instance components in the controller of the system.

[0022] Figure 3 The present invention is a method for operating in the contralateral and ipsilateral crotch veins according to the principles of the present invention. Figure 1A A flow chart of exemplary steps for implementing a system to improve cardiac performance.

[0023] Figures 4A to 4D The invention is described according to the principle of the present invention. Figure 1A The system operates in the contralateral and ipsilateral crotchal veins.

[0024] Figure 5 The invention is a method for operating in the contralateral and ipsilateral subclavian veins according to the principles of the present invention. Figure 1A A flow chart of exemplary steps for implementing a system to improve cardiac performance.

[0025] Figures 6A to 6D The invention is described according to the principle of the present invention. Figure 1A The system is operated in the contralateral and ipsilateral subclavian vein.

[0026] Figure 7 Another exemplary system for improving cardiac function is described that includes two dual balloon catheters constructed according to the principles of the present disclosure.

[0027] Figure 8 The invention describes the method of inserting a needle into the contralateral and ipsilateral crotch vein and into the contralateral and ipsilateral subclavian vein according to the principles of the present invention. Figure 7 system.

[0028] Fig. 9 is a graph illustrating selective modulation of vascular resistance according to the principles of the present disclosure.

[0029] Fig.10 Another exemplary system for improving cardiac function is described that includes two balloon catheters constructed according to the principles of the present disclosure.

[0030] Fig.11 The present invention is a method for operating in the superior vena cava (SVC) and the inferior vena cava (IVC) according to the principles of the present invention. Fig.10 A flow chart of exemplary steps for implementing a system to improve cardiac performance.

[0031] Figures 12A to 12D The invention is described according to the principle of the present invention. Fig.10 The system operates within the SVC and IVC.

[0032] Fig.13 The invention can be used in accordance with the principle of the present disclosure Figure 1A , 7 and an additional system for improving cardiac performance when used in combination with the systems of 10. DETAILED DESCRIPTION

[0033] In human anatomy, deoxygenated blood returns to the heart through the vena cava, which includes the superior and inferior vena cava, which are coupled to the right atrium of the heart. From the right atrium, blood moves through the tricuspid valve to the right ventricle, where it is pumped to the lungs via the pulmonary artery. Oxygenated blood returns from the lungs to the left atrium via the pulmonary veins. The oxygenated blood then enters the left ventricle, which pumps blood to the rest of the body via the aorta.

[0034] Attempts have been made to address heart failure by treating various aspects of heart failure, but none have been intended or capable of reducing left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic pressure (LVEDP), left ventricular end-diastolic diameter (LVEDD), right ventricular end-diastolic volume (RVEDV), or right ventricular end-diastolic pressure (RVEDP) without causing potentially serious side effects. In view of the foregoing shortcomings of previously known systems and methods for regulating venous return to address heart failure, it would be desirable to provide systems and methods for treating acute and chronic heart failure that reduce the risk of worsening comorbidities associated with the disease, and prevent or reverse cardiac remodeling. It would be further desirable to provide systems and methods for reducing the workload on the heart while increasing cardiac output and improving perfusion to a patient's heart.

[0035] According to one aspect of the present disclosure, the applicant has determined that controlling the return of venous blood to the right ventricle by intermittent venous occlusion beneficially reduces RVEDP, RVEDV, LVEDP and LVEDV without adversely reducing left ventricular systolic pressure (LVSP). In theory, selective intermittent occlusion of the venous vascular system will further reduce the risk of worsening renal congestion. In patients with heart failure, congestion of the kidneys can impair renal function due to volume overload and neurohormonal activation. In cases where a weak heart is unable to pump as much blood, volume overload can occur, which leads to reduced blood flow through the kidneys. In the case of reduced blood flow through the kidneys, less blood is filtered by the kidneys, and less water is released via urination, resulting in excess volume being retained in the body. With excess volume, the heart pumps less and less efficiently, and as the body gradually becomes more congested, the patient eventually dies.

[0036] By reducing the flow into the right atrium, the volume within the left ventricle is ultimately reduced, allowing the muscle fibers to stretch within the normal range, naturally increasing the force of contraction, and allowing the heart to drive more fluid to the kidneys. The kidneys can then extract water, which can be removed from the body through urination. It is further understood that during venous occlusion (e.g., SVC occlusion), a negative pressure sink is generated in the right atrium caused by a sudden decrease in right atrial pressure and volume, for example, as described in U.S. Pat. No. 10,842,974 to Kapur et al., the entire contents of which are incorporated herein by reference. Therefore, the flow from the renal vein can be accelerated, thereby enhancing the kidneys to relieve congestion and promote blood flow through the kidneys, thereby increasing urine output. Therefore, venous occlusion can benefit patients with heart failure by reducing cardiopulmonary pressure and promoting decongestion.

[0037] Applicants understand that intermittent occlusion of the venous vasculature (i.e., unloading the cardiopulmonary burden) for a period of time (e.g., minutes, hours, days, weeks, or months) will beneficially allow the patient's heart to stop or recover from remodeling of the myocardium. The systems described herein enable the myocardium to transition from a pressure-stroke volume curve indicative of heart failure toward a pressure-stroke volume curve more similar to that of a healthy heart.

[0038] In general, the systems and methods of the present disclosure can be used to treat any disease to improve cardiac function by preventing or reversing myocardial remodeling, and in particular, in patients with heart failure. These conditions include, but are not limited to, for example, patients with systolic heart failure, diastolic (non-systolic) heart failure, decompensated heart failure (ADHF), chronic heart failure, acute heart failure and pulmonary hypertension, heart attack, heart failure with preserved ejection fraction, right heart failure, systolic and restrictive cardiomyopathy, and cardiorenal syndrome (types 1 to 5). The systems and methods of the present invention can also be used as preventive measures to alleviate the sequelae of acute right or left ventricular myocardial infarction, pulmonary hypertension, RV failure, post-cardiac shock, or rejection after orthotopic heart transplantation (OHTx), or can be used in other ways for cardiorenal applications and / or treatment of renal dysfunction, liver dysfunction, or lymphatic congestion. In addition, the systems and methods of the present disclosure can reduce the length of hospital stay caused by the various diseases described herein, including at least acute exacerbations.

[0039] The relationship between left ventricular pressure or left ventricular volume and stroke volume is often referred to as the Frank-Starling relationship or "Starling curve". The relationship shows that stroke volume depends on preload, contractility and afterload. Preload refers to the amount of blood returned to the heart; contractility is defined as the inherent ability of the myocardium to contract; and afterload is determined by vascular resistance and impedance. In heart failure due to diastolic or systolic dysfunction, reduced stroke volume leads to increased volume and increased pressure in the left ventricle, which can lead to pulmonary edema. Increasing ventricular volume and pressure also leads to increased workload and increased myocardial oxygen consumption. This overwork of the heart leads to worsening heart function because the heart becomes increasingly hypoxic due to a mismatch between supply and demand. In addition, as the volume and pressure inside the heart increase, contractile function deteriorates due to the stretching of the myocardium. This condition is called "congestive heart failure".

[0040] In the typical Starling curve of a normal heart, the stroke volume increases with the increase of LVEDP or LVEDV, and only begins to flatten at very high pressures or volumes, that is, the slope of the curve decreases. Patients who have just experienced acute myocardial infarction (AMI) will show a decrease in stroke volume at each value of LVEDV or LVEDP. However, since the heart has just begun to experience the overload caused by the local effects of the infarction, the myocardial contractility of the entire ventricle is still relatively good, and the stroke volume is still relatively high at low LVEDP or LVEDV. In contrast, patients who have experienced cardiac damage in the past may experience a gradual deterioration of cardiac function because the myocardium remodels over time to compensate for the increased workload and reduced oxygen availability. As mentioned above, this can cause the stroke volume to gradually decrease because the ventricle is dilated due to the generally higher volume and pressure during each stage of the cardiac cycle. Therefore, as LVEDP or LVEDV increases, the stroke volume continues to decline until the heart fails or the patient dies from a circulatory-related disease.

[0041] For a normal heart, as end-diastolic volume increases, cardiac output increases. However, for a healthy heart, beyond a certain point, increasing end-diastolic volume no longer results in increased cardiac output, and continued increases in end-diastolic volume do not result in further increases in cardiac output. In contrast, for patients with heart failure, further increases in end-diastolic volume do not result in a generally flat stroke volume, but instead a decrease in stroke volume. Thus, increasing EDV in patients with HF results in further decreases in SV, leading to a downward spiral of cardiac function and ultimately death. The phenomenon known as "diastolic ventricular interaction" arises in part due to the structural arrangement of the heart chambers. As discussed, for example, in J. Atherton et al., entitled "Diastolic ventricular interaction in chronic heart failure," Lancet 1997; 349: 1720-24, the pericardium limits the extent to which the ventricles of the failing heart can expand. Therefore, as the right ventricular end-diastolic volume increases, the left ventricular end-diastolic volume necessarily decreases. As reported in the literature, the reduction in right ventricular diastolic filling caused by external lower body suction allows augmentation of left ventricular diastolic filling.

[0042] Applicants understand that the aforementioned phenomena can be advantageously used in the context of the present disclosure to improve cardiac performance. Specifically, in the case of heart failure and the presence of pulmonary hypertension, right ventricular congestion can push the ventricular septum toward the left ventricular cavity due to increased volume overload, thereby reducing LV stroke volume and cardiac output. By occluding the veins flowing to the right atrium, right ventricular pressure and volume are reduced. This in turn will move the ventricular septum away from the LV cavity, allowing for increased left ventricular stroke volume and enhanced cardiac output. For these reasons, venous occlusion according to the principles of the present disclosure can advantageously alter diastolic ventricular interactions and enhance cardiac output. Specifically, with respect to diastolic heart failure, venous occlusion according to the principles of the present invention can provide a reduction in cardiac filling pressures, increase LV relaxation (tau), increase LV capacitance, increase diastolicity, reduce LV stiffness, and reduce cardiac strain. The disclosed system and method of inducing intermittent venous occlusion to reduce the volume and therefore pressure of blood that enters the right ventricle of a HF patient and then must be pumped by the left ventricle reduces the myocardial workload and wall stress throughout the cardiac cycle, reduces myocardial oxygen consumption, and improves contractile function. This improves cardiac function by moving the patient's cardiac contractility toward the healthy range of the patient's Frank-Starling curve.

[0043] Reference Figure 1A and 1B , an exemplary system 100 for vein occlusion is provided. The system 100 includes a balloon catheter 101, the balloon catheter 101 including: a catheter 106 having a proximal region 102 and a distal region 104 coupled to a controller 200; and one or more independently actuatable flow restriction elements, such as a first flow restriction element 108 and a second flow restriction element 110, disposed on the distal region 104. The first flow restriction element 108 and the second flow restriction element 110 are fluidly coupled to the controller 200, and the controller 200 is programmed to independently and intermittently actuate the first flow restriction element 108 and the second flow restriction element 110, such as according to a predetermined actuation scheme stored in a memory of the controller 200.

[0044] like Figure 1A, the second flow restriction element 110 is disposed on the catheter 106 proximal to the first flow restriction element 108. The first flow restriction element 108 and the second flow restriction element 110 can be sufficiently spaced along the catheter 106 so that the first flow restriction element 108 can be disposed in a first portion of a vein, such as the contralateral side of the vein, and the second flow restriction element 110 can be disposed in a second portion of the same vein, such as the same side of the same vein. For example, the first flow restriction element 108 can be sized and shaped to be disposed in the contralateral crotch vein, while the second flow restriction element 110 can be sized and shaped to be disposed in the ipsilateral crotch vein. In addition, the first flow restriction element 108 can be sized and shaped to be disposed in the contralateral subclavian vein, while the second flow restriction element 110 can be sized and shaped to be disposed in the ipsilateral subclavian vein, as described in further detail below.

[0045] In addition, the system 100 may include one or more sensors for measuring one or more parameters (e.g., heart rate, blood flow rate, blood volume, and / or pressure including cardiac filling pressure) across the system 100 and generating signals indicative of the measured parameters, such as sensors 103, 105, 107. For example, the sensor 103 may be disposed on the conduit 106 proximal to the second flow restriction element 110, the sensor 105 may be disposed on the conduit 106 between the first flow restriction element 108 and the second flow restriction element 110, and the sensor 107 may be disposed on the conduit 106 distal to the first flow restriction element 108, such as Figure 1A Alternatively, the one or more sensors may be one or more fluid columns within the conduit 106 such that pressure may be measured at the proximal region 102 of the conduit 106. The sensor 105 may be used to determine the degree of occlusion caused by the second flow restriction element 110, for example by monitoring the pressure drop across the second flow restriction element 110, and the sensor 107 may be used to determine the degree of occlusion caused by the first flow restriction element 108, for example by monitoring the pressure drop across the first flow restriction element 108.

[0046] The catheter 106 may include a flexible tube. The distal region 104 of the catheter 106 may be configured for placement in the patient's venous vasculature, such as the crotch vein, subclavian vein, SVC, or IVC, as described in further detail below. The distal end of the catheter 106 may include a tapered atraumatic tip. Figure 1A, the first flow restriction element 108 and the second flow restriction element 110 are illustrative expandable balloons that can be transformed between a contracted state that allows intracavitary placement and an expanded deployment state to selectively obstruct blood flow into the patient's right atrium. The first flow restriction element 108 and the second flow restriction element 110 can be sized and shaped to completely occlude the target vein in the expanded state. In addition, the catheter 106 can include an anchoring mechanism that is configured to anchor the flow distal region 104 to the target venous vasculature. For example, the anchoring mechanism can be contractible for delivery in a contracted state and expandable after being released from a delivery device (e.g., a sheath). The anchoring mechanism can be coupled to the catheter 106 close to the second flow restriction element 110, between the first flow restriction element 108 and the second flow restriction element 110, or away from the first flow restriction element 108, or a combination thereof.

[0047] Reference Figure 2 , an exemplary controller 200 is provided. The controller 200 may house: a drive mechanism 220 (e.g., a motor, a pump) for actuating the first flow restriction element 108 and the second flow restriction element 110; a processor 202 programmed to control signals to the drive mechanism 210; and additional optional sensors for monitoring physiological parameters of the patient, such as heart rate or blood pressure. The controller 200 may include or be fluidly coupled to a source of an inflation medium (e.g., a gas or fluid), for example, a first inflation source 212 fluidly coupled to the first flow restriction element 108 and a second inflation source 214 fluidly coupled to the second flow restriction element 110. In response to commands from the processor 202, the drive mechanism 210 may be actuated to transfer inflation medium between the first inflation source 212 and the second inflation source 214 and the first flow restriction element 108 and the second flow restriction element 110, respectively.

[0048] like Figure 1B , the catheter 106 may include a first gas-filled lumen 114 for fluidly coupling the first flow-restricting element 108 with the first gas-filled source 212 and a second gas-filled lumen 116 for fluidly coupling the second flow-restricting element 110 with the second gas-filled source 214. The proximal ends of the first gas-filled lumen 114 and the second gas-filled lumen 116 may each be connected to a side arm tube that terminates in, for example, a 3-way stopcock or a standard Luer lock fitting. Each side arm tube may have a clamp that is configured to enable / disable flow through the corresponding lumen. In addition, the proximal region 102 of the catheter 106 may include a hub that may be fixed to the patient, for example, via suture holes integrated in the hub or a through hole compatible with a stat lock. In addition, the catheter 106 may include a guidewire lumen 112 that may be sized and shaped to receive a guidewire therebetween to facilitate delivery of the distal region 104 of the catheter 106 to a target location within the venous vascular system of the patient.

[0049] When either or both of the first flow restriction element 108 and the second flow restriction element 110 are inflated with an inflation medium, they partially or completely occlude venous blood flow through the patient's corresponding vein, and when the inflation medium is withdrawn, the first flow restriction element 108 and / or the second flow restriction element 110 are deflated to remove the occlusion, thereby allowing flow to be restored in the corresponding vein. The flow restriction elements can each be a balloon, which preferably includes a compliant or semi-compliant material, such as nylon, which allows the degree of expansion of the balloon to be adjusted to achieve the desired degree of partial or complete occlusion of the venous vascular system. In addition, when partially external, the catheter 106 provides a fail-safe design because the flow restriction element can only be expanded to provide occlusion when the proximal end of the catheter 106 is coupled to the controller 200. This quick disconnect coupling at the proximal region 102 allows the catheter 106 to be quickly disconnected from the controller 200 for cleaning and / or emergency situations.

[0050] Reference again Figure 2 , the controller 200 preferably also includes a power source 206 (e.g., a battery) that provides the power required to operate the processor 202, the data transfer circuit 208, and the drive mechanism 210. When the controller 200 is implanted, the power source 206 can be charged via an external power source, for example, transcutaneously via a corresponding induction coil. The controller 200 can be sized and weighted so that it can be worn in a harness under the patient's clothing so that the system can be used while the patient is ambulatory, or so that the controller 200 can be implanted in the patient's body. As discussed below, the processor 202 includes a memory 204 for storing computer software for operating the controller 200. The controller 200 can be configured for implantation in a suitable location in the patient's body, for example, subcutaneously below the clavicle. In such an embodiment, the implantable controller is configured for bidirectional communication with an external controller (e.g., a computing device or a system-specific device). The external controller can be used, for example, to charge the battery of the implantable controller via a respective induction coil in or coupled to each controller, and can receive data indicative of sensed parameters resulting from the patient's ambulatory activity, including heart rate, blood flow rate, blood volume, pressures including cardiac filling pressures.

[0051] The processor 202 may be programmed to maintain partial or complete venous occlusion for a preset number of cardiac cycles according to a predetermined actuation scheme determined at the time of initial implantation of the catheter. For example, the predetermined actuation scheme may expand only the first flow restriction element 108 for a first time period, expand both the first flow restriction element 108 and the second flow restriction element 110 for a second time period after the first time period, deflate the first flow restriction element 108 so that only the second flow restriction element 110 expands for a third time period after the second time period, and expand both the first flow restriction element 108 and the second flow restriction element 110 for a fourth time period after the third time period. The predetermined actuation scheme may be repeated throughout a course of treatment. Thus, in a course of treatment according to the predetermined actuation scheme, at least one or both of the first flow restriction element 108 and the second flow restriction element 110 will expand throughout the course of treatment, thereby providing at least 70% to 90%, or preferably at least 80% overall occlusion throughout the course of treatment to thereby effectively reduce preload.

[0052] Each of the first, second, third, and fourth time periods may be between 1 and 15 minutes, or preferably between 5 and 10 minutes. For example, the predetermined actuation scheme may expand only the first flow restriction element 108 for five minutes, then cause both the first flow restriction element 108 and the second flow restriction element 110 to expand for five minutes, then expand only the second flow restriction element 110 for five minutes, and then cause both the first flow restriction element 108 and the second flow restriction element 110 to expand for five minutes.

[0053] In one embodiment, the data transmission circuit 208 monitors inputs from external sensors (e.g., sensors 103, 105, 107 positioned on the catheter 200) and provides the signals to the processor 200. The processor 200 may be programmed to receive inputs from the data transmission circuit 208 and adjust the time intervals during which the first flow restriction element 108 and the second flow restriction element 110 are maintained in an expanded state, or adjust the degree of occlusion caused by the first flow restriction element 108 and the second flow restriction element 110. Thus, for example, the sensors 103, 105, 107 positioned on the catheter 106 may measure parameters such as heart rate, blood flow rate, blood volume, pressures including cardiac filling pressure and central venous pressure. The outputs of the sensors 103, 105, 107 are relayed to the data transmission circuit 208 of the controller 200, which may pre-process the input signals before they are supplied to the processor 202, for example, extracting and digitizing the outputs of the sensors. The signals provided to processor 202 allow evaluation of the effectiveness of the flow restricting element, for example, by demonstrating reduced venous pressure during occlusion and during patency, and can be used by the patient or clinician to determine how much occlusion is needed to regulate venous return to the heart based on the severity of congestion in the patient.

[0054] As another example, at least one of the sensors 103, 105, 107 may be one or more electrodes for sensing the patient's heart rate. It may be desirable to adjust the predetermined actuation scheme in response to the patient's ambulatory activity, for example, the time interval for which the venous occlusion of each flow restriction element is maintained, which will generally be reflected in the patient's hemodynamic state by sensed physiological parameters (e.g., heart rate, blood flow rate, blood volume, pressures including cardiac filling pressure and / or central venous pressure). Thus, the electrodes may provide signals to the data transmission circuit 208, which in turn processes the signals for use by a programmed routine executed by the processor 202. For example, if the occlusion of the first flow restriction element 108 is maintained for a time programmed during initial system setup, such that the flow restriction element is deployed for 15 minutes and then released for 5 minutes before re-inflation, it may be desirable to reduce the occlusion time interval to 10 minutes or longer depending on the patient's physical activity level, as detected by changes in heart rate, blood flow rate, blood volume, pressures including cardiac filling pressure and / or central venous pressure above or below a predetermined threshold. Sensor inputs (e.g., hemodynamic status) provided to the data transmission circuit 208 may also be used to adjust the duty cycle of the flow restriction element in response to the detected activity level of the patient. In addition, the processor 202 may be programmed to maintain partial or complete occlusion in the corresponding vein for a preset number of cardiac cycles after adjusting the predetermined occlusion time interval.

[0055] The data transmission circuit 208 may also be configured to provide two-way data transmission, for example, by including wireless circuitry to transmit data from the controller 200 to an external unit for display, viewing or adjustment. For example, the data transmission circuit 208 may include a Bluetooth circuit that enables the controller 200 to communicate with an external controller, for example, a patient's computing device, such as a smart phone, laptop, smart watch or tablet computer, on which a dedicated application has been installed to communicate and / or control the controller 200. In this way, the controller 200 can use a properly configured mobile application to send information about the function of the system directly to the computing device to display important physiological or system parameters. In addition, the patient can view the data displayed on the screen of the computing device and determine whether he needs to seek medical assistance to resolve the fault or adjust the system parameters. In addition, the mobile application resident on the computing device can be configured to automatically initiate an alert to the clinician's monitoring service via a cellular telephone network.

[0056] Reference Figure 3 , provided for delivery and operation in the common crotch vein of the patient Figure 1A An exemplary method 300 of improving cardiac performance using the system 100 is provided. Figures 4A to 4D302, a guide wire may be inserted into a patient through a femoral vein, passed up the femoral vein toward a crotch vein, and across the crotch vein on the ipsilateral side to the contralateral side of the crotch vein. In step 304, a catheter 106 may be inserted into an introducer sheath such that the first flow restriction element 108 and the second flow restriction element 110 are in their contracted delivery states within the sheath. Next, the introducer sheath and the balloon catheter 101 disposed therein may be advanced over the guide wire, such as through a guide wire lumen 112 of the catheter 106, until the first flow restriction element 108 is positioned within the sheath within the contralateral crotch vein and the second flow restriction element 110 is positioned within the ipsilateral crotch vein. Next, the guide wire may be removed from the catheter 106. The guide wire lumen 112 may be flushed before closing the guide wire lumen 112 via a cap or clamp coupled to a side arm of the guide wire lumen 112. Next, the proximal end of the catheter 106 may be coupled to the controller 200 such that the first inflation lumen 114 is coupled to the first inflation source 212 and the second inflation lumen 116 is coupled to the second inflation source 214 .

[0057] At step 306, the sheath may be retracted relative to the catheter 106 such that the first flow restriction element 108 is deployed within the contralateral crotch vein and the second flow restriction element 110 is deployed within the ipsilateral crotch vein. At step 308, the first flow restriction element 108 and the second flow restriction element 110 may be actuated via the controller 200 to expand within respective portions of the common crotch vein according to a predetermined actuation scheme to intermittently occlude blood flow through the contralateral and ipsilateral crotch veins to thereby reduce cardiac preload and selectively increase arterial vascular resistance of the patient's limb in fluid communication with the occluded veins while increasing perfusion to the patient's heart and organs.

[0058] For example, for a first period of time, such as five minutes, the predetermined actuation scheme may cause only the first flow restricting element 108 to expand in the contralateral crotch vein, such as Figure 4A At a second time period after the first time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 108 and the second flow restriction element 110 to expand in the contralateral and ipsilateral crotch veins, respectively. Figure 4B For a third time period after the second time period, for example, five minutes, the predetermined actuation scheme may cause the first flow restriction element 108 to deflate so that only the second flow restriction element 110 remains inflated within the ipsilateral crotch vein, such as Figure 4C For a fourth time period after the third time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 108 and the second flow restriction element 110 to expand in the contralateral and ipsilateral crotch veins, respectively, such as Figure 4D. This actuation pattern may be repeated throughout the course of treatment. Thus, for a fifth time period after the fourth time period, for example, five minutes, the predetermined actuation scheme may cause the second flow restriction element 110 to deflate so that only the first flow restriction element 108 remains inflated within the contralateral crotch vein, and so on.

[0059] Reference Figure 5 , provided for delivery and operation within the patient's subclavian vein Figure 1A An exemplary method 500 of improving cardiac performance using the system 100 is provided. Figures 6A to 6D 5. In step 502, a guide wire may be inserted into a patient through the jugular vein, down the jugular vein toward the subclavian vein, and across the subclavian vein on the ipsilateral side to the contralateral subclavian vein. In step 504, the catheter 106 may be inserted into the introducer sheath so that the first flow restriction element 108 and the second flow restriction element 110 are in their contracted delivery states within the sheath. The introducer sheath and the balloon catheter 101 disposed therein may then be advanced over the guide wire, such as through the guide wire lumen 112 of the catheter 106, until the first flow restriction element 108 is positioned within the sheath within the contralateral subclavian vein and the second flow restriction element 110 is positioned within the ipsilateral subclavian vein. The guide wire may then be removed from the catheter 106. As described above, the guide wire lumen 112 can be flushed before being closed via a cap or clamp on a side arm coupled to the guide wire lumen 112, and the proximal end of the catheter 106 can then be coupled to the controller 106 such that the first inflation lumen 114 is coupled to the first inflation source 212 and the second inflation lumen 116 is coupled to the second inflation source 214.

[0060] At step 506, the sheath may be retracted relative to the catheter 106 such that the first flow restriction element 108 is deployed within the contralateral subclavian vein and the second flow restriction element 110 is deployed within the ipsilateral subclavian vein. At step 508, the first flow restriction element 108 and the second flow restriction element 110 may be actuated via the controller 200 to expand within respective portions of the subclavian vein according to a predetermined actuation scheme to intermittently occlude blood flow through the contralateral and ipsilateral subclavian veins to thereby reduce cardiac preload and selectively increase arterial vascular resistance of the patient's limb in fluid communication with the occluded veins, while increasing perfusion to the patient's heart and organs.

[0061] For example, for a first period of time, such as five minutes, the predetermined actuation scheme may cause only the first flow restriction element 108 to expand in the contralateral subclavian vein, such as Fig. 6A In a second time period after the first time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 108 and the second flow restriction element 110 to expand in the contralateral and ipsilateral subclavian veins, respectively. Figure 6B For a third time period after the second time period, for example, five minutes, the predetermined actuation scheme may cause the first flow restriction element 108 to deflate so that only the second flow restriction element 110 remains inflated in the ipsilateral subclavian vein, as shown in FIG. Figure 6C For a fourth time period after the third time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 108 and the second flow restriction element 110 to expand in the contralateral and ipsilateral subclavian veins, respectively. Fig.6D . This actuation pattern may be repeated throughout the course of treatment. Thus, for a fifth time period after the fourth time period, for example, five minutes, the predetermined actuation scheme may cause the second flow restriction element 110 to deflate so that only the first flow restriction element 108 remains inflated in the contralateral subclavian vein, and so on.

[0062] Reference Figure 7 , an exemplary system 700 for vein occlusion is provided. System 700 can be configured similarly to system 100, except that system 700 includes two balloon catheters (e.g., a first balloon catheter 101 and a second balloon catheter 101'). The first balloon catheter 101 of system 700 can be configured similarly to the balloon catheter of system 100, and the second balloon catheter 101' can be configured similarly to the first balloon catheter 101, with similar components having the same major element numbers. However, the second balloon catheter 101' differs from the first balloon catheter 101 in that the third flow restriction element 108' and the fourth flow restriction element 110' can be sized and shaped to completely occlude the contralateral and ipsilateral subclavian veins, respectively, while the first flow restriction element 108 and the second flow restriction element 110 can be sized and shaped to completely occlude the contralateral and ipsilateral crotch veins, respectively, or vice versa.

[0063] Therefore, if Figure 8, a first balloon catheter 101 can be inserted into a patient via the femoral vein using the method 300 described above, such that the first flow restriction element 108 is deployed in the contralateral crotch vein, and the second flow restriction element 110 is deployed in the ipsilateral crotch vein, and a second balloon catheter 101' can be inserted into a patient via the jugular vein using the method 500 described above, such that the third flow restriction element 108' is deployed in the contralateral subclavian vein, and the fourth flow restriction element 110' is deployed in the ipsilateral subclavian vein. The first flow restriction element 108 and the second flow restriction element 110 can be actuated via the controller 200 to expand in respective portions of the common crotch vein according to a predetermined actuation scheme to intermittently occlude blood flow through the contralateral and ipsilateral crotch veins, and the third flow restriction element 108' and the fourth flow restriction element 110' can be actuated via the controller 200' to expand in respective portions of the subclavian vein according to a predetermined actuation scheme to intermittently occlude blood flow through the contralateral and ipsilateral subclavian veins to thereby reduce cardiac preload and selectively increase arterial vascular resistance of the patient's limb in fluid communication with the occluded veins, while increasing perfusion to the patient's heart and organs. Although Figure 7 and 8 Two controllers are illustrated in FIG. 7 , but as will be understood by one skilled in the art, system 700 may include a single controller having a number of inflation sources corresponding to the number of flow restricting elements of system 700 such that both first balloon catheter 101 and second balloon catheter 101 ′ may be coupled to the controller.

[0064] Selective actuation of first balloon catheter 101 and second balloon catheter 101' provides corresponding selective occlusion of respective veins (e.g., common crotch vein and subclavian vein), thereby selectively increasing vascular resistance in the respective veins, which in turn can selectively reduce arterial blood flow to a limb in fluid communication with the occluded veins. Fig. 9 is a graph illustrating selective modulation of vascular resistance according to the principles of the present disclosure. Fig. 9 , Q1 represents arterial blood flow from the heart to the patient's upper limbs (e.g., head and arms), Q2 represents arterial blood flow from the patient's lungs to the heart H and central organs, and Q3 represents arterial blood flow from the heart to the patient's lower limbs (e.g., legs). In addition, R1 represents arterial vascular resistance to the patient's upper limbs, R2 represents arterial vascular resistance to the patient's heart and central organs, and R4 represents arterial vascular resistance to the patient's lower limbs.

[0065] In addition, R3 represents the venous vascular resistance caused by occluding the venous vascular system (e.g., the subclavian vein) in fluid communication with the patient's upper limbs through the second balloon catheter 101', and R5 represents the venous vascular resistance caused by occluding the venous vascular system (e.g., the common crotch vein) in fluid communication with the patient's lower limbs through the first balloon catheter 101. R6 represents the venous vascular resistance of the collateral return of blood flow from the patient's lower limbs, and R7 represents the venous vascular resistance of the collateral return of blood flow from the patient's upper limbs. Therefore, when the first balloon catheter 101 is actuated to occlude the common crotch vein, for example, via intermittent expansion of the first flow restriction element 108 and the second flow restriction element 110, R5 and accordingly R6 increase, which results in a corresponding increase in R4 and a corresponding decrease in Q3. Similarly, when the second balloon catheter 101 ' is actuated to occlude the subclavian vein, for example via intermittent inflation of the first and second flow restricting elements 108', 110', R3 and accordingly R7 increase, which results in a corresponding increase in R1 and accordingly a corresponding decrease in Q1.

[0066] Thus, the patient's mean arterial pressure (MAP) increases, similar to the result of "giving" a vasopressor to the patient. However, since there is no increase in R2 (arterial vascular resistance to the patient's heart and central organs), with the higher MAP, Q2 increases (i.e., perfusion to the patient's heart and organs increases), but the total flow to the body decreases. This is because the changes in Q1 and Q3 are greater than the change in Q2. Thus, while the patient's heart and central organs are kept perfused, the patient's heart is relieved in a manner equivalent to reducing the total flow to the system. Thus, assuming 30% of the blood flow is going to the patient's upper extremities and 20% of the blood flow is going to the patient's lower extremities, the patient's heart can be relieved of up to 50% of the load.

[0067] Thus, the system 700 can improve perfusion to the patient's heart and central organs by selectively and intermittently occluding the venous vasculature of the patient's lower and upper extremities (e.g., increasing R5 and / or R3), which reduces arterial blood flow to the patient's lower and / or upper extremities, e.g., reducing Q3 and / or Q1. Thus, arterial blood flow to the patient's extremities (e.g., lower extremities, such as the legs) can be selectively reduced to maintain or improve perfusion to the patient's heart and central organs. This can be critical for patients who are in situations requiring at least minimal / adequate perfusion to the heart and who can withstand a temporary reduction in arterial blood flow to the legs (e.g., patients who require less oxygen in the legs). As will be appreciated by those skilled in the art, selective modulation of vascular resistance can be achieved by using the system 100 in the common crotch vein according to method 300 or in the subclavian vein according to method 500, or by using the system 700 in both the common crotch vein and the subclavian vein. Furthermore, according to another aspect of the present disclosure, selective modulation of vascular resistance may be achieved by selectively and intermittently occluding a patient's superior vena cava (SVC) and inferior vena cava (IVC).

[0068] Reference Fig.10 , an exemplary system 1000 for vein occlusion is provided. The system 1000 includes a first balloon catheter 1001 and a second balloon catheter 1001'. The first balloon catheter 1001 includes: a catheter 1006 having a proximal region 1002 and a distal region 1004 coupled to the controller 200"; and an independently actuatable first flow restriction element 1008 disposed on the distal region 1004. Fig.10 , the first flow restriction element 1008 can be an inflatable balloon capable of transitioning between a deflated state that allows intraluminal placement and an inflated deployed state to thereby selectively obstruct blood flow into the right atrium of the patient. The first flow restriction element 1008 can be sized and shaped to completely occlude a target vein, such as the SVC, in the inflated state. Additionally, the first balloon catheter 1001 can include one or more sensors, such as a sensor 1003 disposed on the catheter 1006 proximal to the first flow restriction element 1008 and a sensor 1005 disposed on the catheter 1006 distal to the first flow restriction element 1008, for measuring one or more parameters across the system 1000 and generating a signal indicative of the measured parameters. In addition, the first flow restriction element 1008 is fluidly coupled to the controller 200", which can be constructed similarly to the controller 200, except that the controller 200" can have only a single inflation source. Therefore, the controller 200" is programmed to independently and intermittently actuate the first flow restriction element 1008 according to a predetermined actuation scheme stored in the memory of the controller 200".

[0069] Second balloon catheter 1001' may be constructed similarly to first balloon catheter 1001, having similar components with the same major reference numerals. However, second flow restriction element 1008' of second balloon catheter 1001' may be sized and shaped to completely occlude the IVC in the expanded state. Additionally, catheter 1006' of second balloon catheter 1001' may be coupled to controller 200'', which may be constructed similarly to controller 200'. Thus, controller 200'' is programmed to independently and intermittently actuate second flow restriction element 1008' according to a predetermined actuation scheme stored in a memory of controller 200''.

[0070] Reference Fig.11 , provided for delivery and operation within the patient's SVC and IVC Fig.10 An exemplary method 1100 of improving cardiac performance using the system 1000 is provided. Figures 12A to 12D 100. In step 1102, a guidewire may be inserted into a patient through the jugular vein, down the jugular vein toward the subclavian vein, and across the subclavian vein toward the SVC. In step 1104, a catheter 1006 may be inserted into an introducer sheath such that a first flow restriction element 1008 is in its contracted delivery state within the sheath. Next, the introducer sheath and the first balloon catheter 1001 disposed therein may be advanced over the guidewire through the guidewire lumen of the catheter 1006 until the first flow restriction element 1008 is positioned within the sheath within the SVC. Next, the guidewire may be removed from the catheter 1006, and the guidewire lumen of the catheter 1006 may be flushed before closing the guidewire lumen via a cap or clamp coupled to a side arm of the guidewire lumen. Next, the proximal end of the catheter 1006 can be coupled to the controller 200", such that the inflation lumen of the catheter 1006, which is fluidically coupled to the first flow restriction element 1008, can be coupled to an inflation source within or fluidly coupled to the controller 200". At step 1106, the sheath can be retracted relative to the catheter 1006, such that the first flow restriction element 1008 is deployed within the SVC.

[0071] At step 1108, a guidewire may be inserted into the patient through the femoral vein, up the femoral vein toward the common crotch vein, and across the common crotch vein toward the IVC. At step 1110, catheter 1006' may be inserted into the introducer sheath such that the first flow restriction element 1008' is in its contracted delivery state within the sheath. The introducer sheath and the second balloon catheter 1001' disposed therein may then be advanced over the guidewire via the guidewire lumen of catheter 1006' until the second flow restriction element 1008' is positioned within the sheath within the IVC. The guidewire may then be removed from catheter 1006', and the guidewire lumen of catheter 1006' may be flushed before closing the guidewire lumen via a cap or clamp coupled to a side arm of the guidewire lumen. Next, the proximal end of the catheter 1006' can be coupled to the controller 200'" such that the inflation lumen of the catheter 1006', which is fluidly coupled to the second flow restriction element 1008', can be coupled to an inflation source within or fluidly coupled to the controller 200'". At step 1112, the sheath can be retracted relative to the catheter 1006' such that the second flow restriction element 1008' is deployed within the IVC.

[0072] At step 1114, the first flow restriction element 1008 and the second flow restriction element 1008' may be actuated via the controllers 200", 200'" respectively to expand in the SVC and IVC according to a predetermined actuation scheme to intermittently occlude blood flow through the SVC and IVC to thereby reduce cardiac preload and selectively increase arterial vascular resistance of the patient's limb in fluid communication with the occluded vein, while increasing perfusion to the patient's heart and organs. For example, for a first time period, such as five minutes, the predetermined actuation scheme may cause only the second flow restriction element 1008' to expand in the IVC, such as Fig. 12A At a second time period after the first time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 1008 and the second flow restriction element 1008' to expand in the SVC and IVC, respectively, as shown in FIG. Fig. 12B For a third time period after the second time period, for example, five minutes, the predetermined actuation scheme may cause the second flow restriction element 1008' to deflate so that only the first flow restriction element 1008 remains inflated within the SVC, such as Fig. 12C For a fourth time period after the third time period, for example, five minutes, the predetermined actuation scheme may cause both the first flow restriction element 1008 and the second flow restriction element 1008' to expand in the SVC and IVC, respectively, as shown in FIG. Fig.12D . This actuation pattern may be repeated throughout the treatment session. Thus, for a fifth time period after the fourth time period, for example, five minutes, the predetermined actuation scheme may cause the first flow restriction element 1008 to deflate so that only the second flow restriction element 1008' remains inflated within the IVC, and so on.

[0073] As mentioned above about Fig. 9 As described, the selective intermittent occlusion of the SVC and IVC by the system 1000 can selectively modulate vascular resistance. For example, the intermittent occlusion of the SVC by the first flow restriction element 1008 of the system 1000 can achieve results equivalent to the intermittent occlusion of the contralateral and ipsilateral subclavian veins by the third flow restriction element 108' and the fourth flow restriction element 110' of the system 700, for example, increasing R3 and R7, and correspondingly increasing R1 and decreasing Q1. In addition, the intermittent occlusion of the IVC by the second flow restriction element 1008' of the system 1000 can achieve results equivalent to the intermittent occlusion of the contralateral and ipsilateral common crotch veins by the first flow restriction element 108 and the second flow restriction element 110 of the system 700, for example, increasing R5 and R6, and correspondingly increasing R3 and decreasing Q3. Therefore, with a higher MAP and no increase in R2, Q2 increases (i.e., perfusion to the patient's heart and organs increases), but the total flow of the body decreases. Thus, the patient's heart is relieved in a manner equivalent to reducing the total flow in the system while maintaining the patient's heart and central organs perfused.

[0074] Reference Fig.13 Additional systems for improving cardiac performance may be used in conjunction with the present disclosure in accordance with the principles of the present disclosure. Figure 1A , 7 and any one of the systems 10. For example, Fig.13 , a system 1000 having a first balloon catheter 1001 positioned within the SVC and a second balloon catheter 1001′ positioned within the IVC can be used with a mechanical circulatory support (MCS) device (e.g., Heart pumps (available from Danvers, Massachusetts) The MCS device includes: a pump, such as an impeller pump, disposed on a distal region of the catheter, wherein the pump can be selectively actuated to pump blood from the left ventricle through an inflow end and discharge the blood into the aorta via an outflow end; and an MCS device controller 200"" operably coupled to the MCS device to actuate the pump to pump blood from the left ventricle to the aorta, thereby relieving the burden on the left ventricle and increasing coronary and systemic perfusion. When the MCS device controller 200"" actuates the pump to pump blood from the left ventricle to the aorta, the MCS device controller 200"" can simultaneously regulate activation and deactivation of the first flow restriction element 1008 to at least partially occlude the SVC, and regulate activation and deactivation of the second flow restriction element 1008' to at least partially occlude the IVC. Alternatively, the first balloon catheter 1001 positioned within the SVC can be used in conjunction with the MCS device without the second balloon catheter 1001' positioned within the IVC to improve cardiac performance. Additionally, a second balloon catheter 1001' positioned in the IVC may be used in conjunction with the MCS device without the need for a first balloon catheter 1001 positioned in the SVC to improve cardiac performance. When any of the systems described herein are used with an MCS device, the size of the MCS may be reduced because the pump of the MCS device will need to provide less flow to provide complete unloading of the heart, thereby reducing arterial access size. Thus, the size of the delivery sheath may also be reduced without increasing vascular recoil to reduce insertion associated with vascular complications, ischemic risk, and compatibility with ostial closure. Additionally, vasodilators may be administered to the patient, which will further increase perfusion to the heart and organs, even for patients with low MAP, while vascular resistance in the arms, head, and legs will continue to be limited.

[0075] Alternatively or in addition, the system 1000 may further include an MCS device configured to be selectively actuated to pump blood from the SVC through an inflow end of the MCS device and to discharge the blood into the pulmonary artery via an outflow end of the MCS device. The controller may also be operably coupled to the MCS device to actuate the pump to pump blood from the SVC to the pulmonary artery, thereby relieving the right ventricle. For example, when the controller actuates the MCS device pump to pump blood from the SVC to the pulmonary artery, the controller may intermittently actuate the first flow restriction element 1008 to at least partially occlude the SVC and actuate the second flow restriction element 1008' to at least partially occlude the IVC.

[0076] Similarly, any of the systems 100 and 700 may also be used in conjunction with any or both of the MCS devices described above to improve cardiac performance in accordance with the principles of the present disclosure described herein. In addition, any of the systems 100 and 700 may also be used with a first balloon catheter 1001 positioned within the SVC and / or a second balloon catheter 1001' disposed within the IVC to improve cardiac performance. For example, the balloon catheter 101 of the system 100 may be positioned within the subclavian vein such that the first flow restriction element 108 is positioned within the contralateral subclavian vein, and the second flow restriction element 110 is positioned within the ipsilateral subclavian vein, and the first flow restriction element 1008 of the second balloon catheter 1001 may be positioned within the SVC. The balloon catheters 101 and the first balloon catheter 1001 may be intermittently actuated according to a predetermined actuation scheme to selectively modulate vascular resistance as described above to improve cardiac performance.

[0077] Although various illustrative embodiments of the present invention are described above, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the present invention. The appended claims are intended to cover all such changes and modifications as fall within the true scope of the present invention.

Claims

1. A system for reducing the workload on a patient's heart to improve cardiac performance, the system comprising: a first flow restricting element configured to be selectively actuated to occlude a first vein in fluid communication with a first limb of the patient; a second flow restricting element configured to be selectively actuated to occlude a second vein in fluid communication with a second limb of the patient; A controller operably coupled to the first flow restriction element and the second flow restriction element, the controller being configured to cause the first and / or second flow restriction elements to expand according to a predetermined actuation scheme to selectively occlude the first and / or second veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

2. The system of claim 1, wherein the first vein is a contralateral crotch vein and the second vein is an ipsilateral crotch vein.

3. The system of claim 2, further comprising a mechanical circulatory support (MCS) device.

4. The system according to claim 2, further comprising: a third flow restriction element operably coupled to the controller and configured to be selectively actuated to occlude a superior vena cava (SVC) of the patient, Wherein the controller is configured to cause the third flow restricting element to expand according to a second predetermined actuation scheme to occlude the SVC and reduce cardiac preload.

5. The system of claim 4, further comprising a mechanical circulatory support (MCS) device.

6. The system of claim 2, further comprising: a third flow restriction element operably coupled to the controller and configured to be selectively actuated to occlude a contralateral subclavian vein of the patient; and a fourth flow restriction element operably coupled to the controller and configured to be selectively actuated to occlude the patient's ipsilateral subclavian vein, The controller is configured to cause the third and / or fourth flow restricting elements to expand according to a second predetermined actuation scheme to selectively occlude the contralateral and / or ipsilateral subclavian veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

7. The system of claim 6, further comprising a mechanical circulatory support (MCS) device.

8. The system of claim 6, further comprising: a fifth flow restriction element operably coupled to the controller and configured to be selectively actuated to occlude a superior vena cava (SVC) of the patient, Wherein the controller is configured to cause the fifth flow restricting element to expand according to a third predetermined actuation scheme to occlude the SVC and reduce cardiac preload.

9. The system of claim 8, further comprising a mechanical circulatory support (MCS) device.

10. The system of claim 2, further comprising: a catheter operably coupled to the controller, The first flow restriction element and the second flow restriction element are disposed on a distal end region of the catheter.

11. The system of claim 1, wherein the first vein is the superior vena cava (SVC) and the second vein is the inferior vena cava (IVC).

12. The system of claim 11, further comprising a mechanical circulatory support (MCS) device.

13. The system of claim 11, further comprising: a first conduit operably coupled to the controller; and a second conduit operably coupled to the controller, The first flow restriction element is disposed on a distal region of the first conduit, and the second flow restriction element is disposed on a distal region of the second conduit.

14. The system of claim 1, wherein the predetermined actuation scheme is programmed to: expanding only the first flow restricting element for a first period of time; expanding the first flow restriction element and the second flow restriction element for a second time period after the first time period; expanding only the second flow restricting element for a third time period subsequent to the second time period; and The first and second flow restricting elements are expanded for a fourth time period after the third time period.

15. The system of claim 1, wherein the predetermined actuation protocol is programmed to occlude at least 70% of the first and second veins during a treatment period.

16. The system of claim 1, wherein the predetermined actuation scheme is programmed in the controller such that the first flow restriction element or the second flow restriction element or both remain occluded throughout a treatment session.

17. The system of claim 1, wherein each occlusion period during a treatment session is at least one minute.

18. The system of claim 1, further comprising one or more sensors configured to measure one or more parameters and to generate one or more signals indicative of the one or more measured parameters.

19. The system of claim 18, wherein a first sensor of the one or more sensors is disposed proximate to the first flow restricting element and a second sensor of the one or more sensors is disposed proximate to the second flow restricting element.

20. The system of claim 18, wherein the controller is configured to adjust the predetermined actuation protocol to selectively occlude the first and / or second vein in response to the one or more signals indicative of the one or more measured parameters.

21. A method for reducing the workload on a patient's heart to improve cardiac performance, the method comprising: positioning a first flow restriction element within a first vein in fluid communication with a first limb of the patient; positioning a second flow-restricting element within a second vein in fluid communication with a second limb of the patient; and The first and / or second flow restricting elements are expanded according to a predetermined actuation scheme to selectively occlude the first and / or second veins to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

22. The method of claim 21, wherein positioning the first flow restricting element within the first vein of the patient comprises positioning the first flow restricting element within a contralateral crotch vein of the patient, and Wherein positioning the second flow restricting element within the second vein of the patient includes positioning the second flow restricting element within an ipsilateral crotchal vein of the patient.

23. The method of claim 22, further comprising: positioning a third flow restricting element within a contralateral subclavian vein of the patient; positioning a fourth flow restriction element within the ipsilateral subclavian vein of the patient; and The third and / or fourth flow restricting elements are expanded according to a second predetermined actuation scheme to selectively occlude the contralateral and / or ipsilateral subclavian vein to reduce cardiac preload and increase mean arterial pressure, thereby selectively increasing the arterial vascular resistance of the patient's limbs while maintaining the arterial vascular resistance of the patient's heart and peripheral organs and increasing perfusion to the patient's heart and peripheral organs.

24. The method of claim 21, further comprising: positioning a third flow-restricting element within the superior vena cava of the patient; and The third flow restricting element is intermittently actuated according to a second predetermined actuation schedule to occlude the SVC and reduce cardiac preload.

25. The method of claim 21, further comprising: positioning a mechanical circulatory support (MCS) device within the patient's heart; and The MCS device is actuated.

26. The method of claim 21, wherein expanding the first and / or second flow restricting element according to the predetermined actuation protocol comprises maintaining the first flow restricting element or the second flow restricting element or both occluded throughout a treatment session.

27. The method of claim 21, wherein expanding the first and / or second flow restricting elements according to the predetermined actuation profile comprises: expanding only the first flow restricting element for a first period of time; expanding the first flow restriction element and the second flow restriction element for a second time period after the first time period; expanding only the second flow restricting element for a third time period subsequent to the second time period; and The first and second flow restricting elements are expanded for a fourth time period after the third time period.

28. The method of claim 21, wherein positioning the first flow-restricting element within the first vein of the patient comprises positioning the first flow-restricting element within the superior vena cava (SVC) of the patient, and Wherein positioning the second flow-restricting element within the second vein of the patient comprises positioning the second flow-restricting element within the inferior vena cava (IVC) of the patient.

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