Blood flow occluder

Abstract

A system for regulating blood flow within a heart includes a stent sized for placement in a blood vessel of the heart. A lumen of the stent is adjustable for cyclically obstructing the flow of the blood through the stent and thereby improving the efficiency of the heart. In one example, an elongate member extends into a chamber of the heart and pressure changes within the heart chamber are communicated to the stent for altering a diameter of the lumen. The elongate member may be a tube for allowing a fluid to move between the stent and the heart chamber. The elongate member may be anchored within the heart, such as along an atrial septum.

Description

BLOOD FLOW OCCLUDERRELATED APPLICATION^ )

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 552,036, filed on February 9, 2024, the complete disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND

[0002] The present invention relates generally to the field of medical devices and procedures.

[0003] Redistribution of blood from the splanchnic venous circulation to the inferior vena cava (IVC) and / or superior vena cava (SVC) can contribute to increases in central venous pressure (CVP), pulmonary artery pressure, and / or pulmonary capillary wedge pressure (PCWP), particularly during periods of elevated sympathetic tone (e.g., exercise) in heart failure patients.SUMMARY

[0004] For purposes of summarizing the disclosure, certain aspects, advantages and novel features have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, the disclosed embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Various embodiments are depicted in the accompanying drawings for illustrative purposes and should in no way be interpreted as limiting the scope of the inventions. In addition, various features of different disclosed embodiments can be combined to form additional embodiments, which are part of this disclosure. Throughout the drawings, reference numbers may be reused to indicate correspondence between reference elements. However, it should be understood that the use of similar reference numbers in connection with multiple drawings does not necessarily imply similarity between respective embodiments associated therewith. Furthermore, it should be understood that the features of the respective drawings are not necessarily drawn to scale, and the illustrated sizes thereof are presented for the purpose ofillustration of inventive aspects thereof. Generally, certain of the illustrated features may be relatively smaller than as illustrated in some embodiments or configurations.

[0006] Figure 1 provides a schematic representation of portions of the splanchnic circulation.

[0007] Figure 2 provides another schematic representation of the splanchnic circulation, illustrating blood flow from the aorta to the inferior vena cava (IVC).

[0008] Figure 3 illustrates portions of the splanchnic venous circulation acting as a blood reservoir between the aorta and the IVC.

[0009] Figures 4A-4D illustrate an example pressure-induced modulation system in accordance with one or more examples.

[0010] Figures 5A and 5B illustrate another example stent for use in a pressure- induced modulation system in accordance with one or more examples.

[0011] Figures 6A and 6B illustrate another example pressure-induced modulation system in accordance with one or more examples.

[0012] Figures 7A and 7B illustrate another example pressure-induced modulation system in accordance with one or more examples.

[0013] Figures 8A and 8B illustrate another example pressure-induced modulation system in accordance with one or more examples.

[0014] Figures 9A and 9B illustrate another example pressure-induced modulation system in accordance with one or more examples.

[0015] Figure 10 provides a flowchart illustrating a process for modulating and / or regulating blood flow within a heart in accordance with one or more examples.DETAILED DESCRIPTION

[0016] The headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0017] Although certain preferred embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise herefrom is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certainembodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.Overview

[0018] The following includes a general description of human cardiac anatomy that is relevant to certain inventive features and embodiments disclosed herein and is included to provide context for certain aspects of the present disclosure.

[0019] Figure 1 provides a schematic representation of portions of the splanchnic circulation 100. The term “splanchnic circulation” refers to blood flow originating from the celiac, superior mesenteric, and inferior mesenteric arteries to the abdominal gastrointestinal organs. The splanchnic circulation 100 receives approximately 25% of the cardiac output and holds a similar percentage of the total blood volume under normal conditions. The splanchnic circulation 100 can act as a site of cardiac output regulation and / or as a blood reservoir. Multiple regulatory pathways are involved in the distribution of the splanchnic circulation.

[0020] Total flow to the splanchnic viscera is controlled by resistance vessels in the mesenteric and hepatic arterial systems. The venous effluents from the splanchnic viscera converge to form the portal vein 3, which supplies approximately 75% of the total blood supply to the liver 24. The portal blood not only is high in substrate concentrations resulting from intestinal absorption but also tends to contain bacteria and endotoxin.

[0021] Renal veins 12 drain blood from the right kidney 14 and left kidney 16 and connect to the inferior vena cava 10 (IVC). The superior mesenteric vein 6 is a major venous tributary of the abdominal cavity that lies laterally to the superior mesenteric artery and serves to drain the vast majority of the organs of the abdominal cavity. The inferior mesenteric vein 8 drains blood from the large intestine. The splenic vein 12 is a blood vessel that drains blood from the spleen, the stomach fundus, and part of the pancreas.

[0022] The portal vein 3 receives blood from the stomach, intestines, pancreas, and spleen 7 and carries it into the liver 24 through the porta hepatis. The porta hepatis serves asthe point of entry for the portal vein 3 and the proper hepatic artery and is the point of exit for the bile passages.

[0023] Following processing of the blood by the liver 24, the blood collects in the central vein at the core of the lobule. Blood from these central veins ultimately converges in the right and left hepatic veins 9, which exit the superior surface of the liver 24 and empty into the IVC 10 to be distributed to the rest of the body.

[0024] The splanchnic venous circulation 100 is highly compliant and can act as a blood reservoir that can be recruited in order to support the need for increased stressed blood volume during periods of elevated sympathetic tone, such as exertion, in order to support increased cardiac output and vasodilation of peripheral vessels supporting active muscles. However, heart failure patients can have multiple comorbidities that prevent them from using that additional blood volume. Such comorbidities can include chronotropic incompetence, inability to increase stroke volume, and / or peripheral microvascular dysfunction. This can lead to venous congestion and / or abrupt rises in pulmonary capillary wedge pressure (PCWP).

[0025] Figure 2 provides another schematic representation of the splanchnic circulation 200, illustrating blood flow from the aorta 8 to the IVC 10. Blood travels from the aorta 8 to the abdominal gastrointestinal organs including the stomach 11, liver 24, spleen, 7, pancreas 13, small intestine 15, and large intestine 17. The splanchnic circulation 200 comprises three major branches of the abdominal aorta 9, including the coeliac artery 19, the superior mesenteric artery 21 (SMA), and the inferior mesenteric artery 23 (IMA). The hepatic portal circulation (e.g., the hepatic artery 18 and / or portal vein 3) delivers the majority of blood flow to the liver 24.

[0026] The coeliac artery 19 is the first major division of the abdominal aorta 8, branching at T12 in a horizontal direction ~1.25 cm in length. It shows three main divisions such as the left gastric artery, common hepatic artery 18, and splenic artery and is the primary blood supply to the stomach 11, upper duodenum, spleen 7, and pancreas 13.

[0027] The SMA 21 arises from the abdominal aorta 8 anteriorly at LI, usually 1 cm inferior to the coeliac artery 19. The five major divisions of the SMA 21 are the inferior pancreaticoduodenal artery, intestinal arteries, ileocolic, right colic, and middle colic arteries. The SMA 21 supplies the lower part of the duodenum, jejunum, ileum, caecum, appendix, ascending colon, and two-thirds of the transverse colon. It is the largest of the splanchnic arterial vessels delivering >10% of the cardiac output and therefore has significant implications for embolic mesenteric ischaemia.

[0028] The IMA 23 branches anteriorly from the abdominal aorta 8 at L3, midway between the renal arteries and the iliac bifurcation. The main branches of the IMA 23 are the left colic artery, the sigmoid branches, and the superior rectal artery. It forms a watershed with the middle colic artery and supplies blood to the final third of the transverse colon, descending colon, and upper rectum.

[0029] Blood flow is conveyed into the liver 24 via the portal vein 3 into sinusoids 25 of the liver 24. The hepatic veins 9 convey the blood from the liver 24 to the IVC 10.

[0030] Figure 3 illustrates portions of the splanchnic venous circulation 300 acting as a blood reservoir 30 between the aorta 8 and the IVC 10. The portal vein 30 conveys blood between the splanchnic organs 27 (e.g., the stomach, spleen, etc.) and the liver sinusoids 25. The liver sinusoids 25 also receive blood from the hepatic artery 18. The splanchnic organs 27 receive blood from the aorta 8 via various splanchnic arteries 29 (e.g., the SMA, IMA, etc.). The amount of blood contained in the portal vein 3 at any given time can be variable.

[0031] For some patients (especially patients experiencing heart failure) fluid redistribution from the splanchnic venous reservoir 30 to the IVC 10 and / or stressed blood volume can contribute to increases in central venous pressure (CVP), pulmonary artery pressure, and / or PCWP. This can be especially problematic during periods of elevated sympathetic tone, such as exertion, and / or can lead to pulmonary congestion that can impact a patient’s quality of life and / or can lead to acute decompensation.

[0032] The splanchnic venous circulation 300, and particularly the portal vein 3, can advantageously provide a blood reserve to support the need for increased stressed blood volume during periods of elevated sympathetic tone. Because blood flow from the splanchnic venous circulation 300 is directed through the hepatic veins 9 and into the IVC 10, devices placed into the hepatic veins 9 and / or IVC 10 to limit blood flow can allow the reservoir 30 to expand with increased blood volume.

[0033] Embodiments described herein can relate to devices and / or methods that can advantageously limit, stagnate, and / or impede blood flow into the IVC 10 from the hepatic veins 9 to increase the pressure gradient between the IVC 10 and the liver and / or splanchnic venous circulation 300. In some embodiments, one or more flow-regulating implants may be configured for placement at least partially within the hepatic veins 9 and / or IVC 10 and / or at one or more junctions between the hepatic veins 9 and the IVC 10. As a result, blood flowing from the splanchnic venous reservoir 30 into the hepatic veins 9 can be slowed to increase blood volume in the splanchnic venous reservoir 30.

[0034] Some approaches to reducing volume redistribution can involve placing fixed orifice flow restrictors at or near the I VC 10. However, while restricting the flow from the hepatic veins 9 can be beneficial in preventing volume redistribution, too much restriction can cause hepatic congestion. It would therefore be advantageous to modulate the response and increase restriction only during volume redistribution.

[0035] Some examples presented herein relate to methods and / or devices for increasing the restriction of blood flow from the hepatic veins 9 and / or IVC 10 into the right atrium as pressures increase in the left atrium. In some instances, a device can comprise two or more interconnected balloons and / or similar devices. The term “balloon” is used herein in accordance with its plain and ordinary meaning and may refer to any inflatable, deflatable, compressible, expandable, and / or fillable device. A balloon may be configured to be inflated and / or filled with a gas, liquid, and / or similar substance.

[0036] In some examples, a first balloon may be disposed at least partially within the left atrium and / or a second balloon may be disposed at least partially in the IVC 10. One or more balloons within the IVC 10 may be disposed at or near a level of one or more hepatic veins 9. One or more balloons can be filled with fluid and / or gas and / or can modulate preload pressures in the heart by alternately expanding and / or compressing. In some examples, one balloon may be inflated while another balloon is deflated.

[0037] The various devices can be implanted using a transcatheter transvenous approach, for example entering through the femoral vein. With a transeptal puncture, the left atrium may be accessed, and one or more balloons can be deployed in the left atrium. Alternatively, one or more balloons may be deployed in the left atrium via navigation through the coronary sinus. The delivery system can then be progressively unsheathed, and other components of the device can be sequentially implanted under fluoroscopic and echo guidance, if necessary.Blood Flow Modulation

[0038] Figures 4A-4D illustrate an example pressure-induced modulation system in accordance with one or more examples. The system can comprise an anchor 402 tethered and / or attached to a stent 404 (e.g., occlusion device). In some examples, the anchor 402 may be disposed at least partially in the left atrium 2 and / or the stent 404 may be disposed at least partially in the IVC 10 and / or right atrium 5. However, the stent 404 may additionally or alternatively be disposed at least partially in the SVC. The anchor 402 and stent 404 may be tethered and / or attached together via one or more tethers 405 (e.g., sutures, wires, and / or lines),which can include a first tether 405 a and / or a second tether 405b. In some examples, the first tether 405a and the second tether 405b may comprise a single tether 405. For example, the tether 405 may form a loop.

[0039] In some examples, the anchor 402 may be disposed adjacent to and / or in contact with an atrial septum 101. For example, the anchor 402 may be disposed against a left atrium 2 side of the atrial septum 101. The anchor 402 may have any suitable shape and / or size. In some examples, the anchor 402 may have a circular shape and / or may be configured to extend along the atrial septum 101 to increase surface coverage between the atrial septum 101 and the anchor 402. A width of the anchor 402 (e.g., extending away from the atrial septum 101) may be less than a diameter of the anchor 402 (e.g., extending along the atrial septum 101). In some examples, the anchor 402 may comprise a pledget and / or similar device and / or may be configured to at least partially seal an opening through the atrial septum 101. The tether 405 may be configured to extend through an opening in the atrial septum 101 to couple to the anchor 402.

[0040] The stent 404 may comprise a frame 403 forming an outer wall 412 and / or an inner wall 414. The stent 404 may also comprise a covering 406 (e.g., skirt) extending at least partially along the frame 403 (e.g., along the inner wall 414). The covering 406 may be at least partially fluid-tight and / or may be configured to occlude the IVC 10 and / or branching blood vessels 9 (e.g., hepatic veins) and / or to prevent fluid from passing through openings and / or cells of the inner wall 414. The tethers 405 may be configured to pull the inner wall 414 and / or covering 406 away from the outer wall 412 to reduce and / or prevent occlusion of the IVC 10 and / or branching blood vessels 9 by the covering 406.

[0041] The anchor 402 may be configured to move in response to movement of the atrial septum 101. For example, the anchor 402 may be configured to harvest deflecting movements of the septum 101 during contractions of the left atrium 2 and / or right atrium 5. The anchor 402 may be at least partially flexible and / or may be sized and / or otherwise constructed to have no or minimal impact on the natural deflection of the septum 101. In some examples, the anchor 402 may be disposed at a point on the septum 101 to maximize the amount of deflection harvested by the anchor 402.

[0042] The tether 405 may form a functional connection between the stent 404 and the anchor 402. The tether 405 can comprise any suitable means for transferring deflection of the septum 101 to the stent 404 via the anchor 402. When the right atrium 5 contracts, the septum 101 can deflect towards the left atrium 2, which can in turn pull the tethers 405 taut. When the left atrium 2 contracts, the septum 101 can deflect towards the right atrium 5,providing slack in the tethers 405. In some examples, the anchor 402 may comprise a spring to provide a threshold to overcome.

[0043] The stent 404 may be deployed in the IVC 10 and / or can include an outer sealing covering 406 along, for example, an interior portion of the stent 404. In some examples, the covering 406 may attach to and / or extend form a distal end 418 of the stent 404. The stent 404 may comprise a frame 403 including an outer wall 412 and / or an inner wall 414 which may be coupled together at the distal end 418 of the stent 404 and / or may be separate at a proximal end 416 of the stent 404.

[0044] The frame 403 may comprise a wire and / or mesh structure. For example, the inner wall 414 and / or outer wall 412 may comprise a network of struts forming one or more open cells (e.g., openings, apertures, etc.). The covering 406 can comprise fabric and / or other suitable materials and / or may be configured to occluding blood flow. In some examples, the covering 406, inner wall 414, and / or outer wall 412 may be biased such that the covering 406 may lay generally flatly against the inner wall 414 to cause occlusion of the hepatic veins 9. In some examples, the inner wall 414 may be configured to bend towards the outer wall 412 (e.g., at the proximal end 416) and / or away from the outer wall 412. For example, the inner wall 414 may be biased to bend into contact and / or close proximity with the outer wall 412 to extend the covering 406 (which may be attached to the inner wall 414) across the hepatic veins 9. The covering 406, inner wall 414, and / or outer wall 412 may be attached to the tethers 405 at or near the proximal end 416 of the stent 404. For example, the tethers 405 may be attached the inner wall 414 to pull the inner wall 414 away from the outer wall 412 and / or may be attached to the covering 406 to pull the covering away from the outer wall 412. When there is slack in the tethers 405, the inner wall 414 and / or covering 406 may sag against and / or towards the outer wall 412. When the tethers 405 are pulled taut, the inner wall 414 and / or covering 406 may be pulled away from the outer wall 412 to allow blood to flow from the hepatic veins 9 into the IVC 10 and / or right atrium 5.

[0045] In some examples, the tether(s) 405 can comprise a lasso-like mechanism configured to cinch the inner wall 414 and / or covering 406 when pulled taut. For example, the tether(s) 405 may form a loop extending circumferentially around the inner wall 414 and / or covering 406. As the tether(s) 405 become taut, the tether(s) 405 may apply force to a full circumference of the inner wall 414 and / or covering 406.

[0046] Figures 4B-1 and 4B-2 provide isolated views of the anchor 402 deployed within the left atrium 2 and / or at the atrial septum 101. As shown in Figure 4B-1, pressure changes in the left atrium 2 and / or right atrium 5 can cause shifting of the atrial septum 101and / or anchor. For example, decreased pressure in the left atrium 2 may push the atrial septum 101 and / or anchor 402 away from right atrium 5 and / or away from a default septum position 438 and / or a default anchor position 432 and / or increased pressure in the left atrium 2 may push the atrial septum 101 and / or anchor 402 towards the right atrium 5 and / or towards the default septum position 438 and / or default anchor position 432. As a result, slack may be created in the tether(s) 405, allowing the inner wall 414 and / or covering 406 of the stent 404 to occlude the hepatic veins 9. Similarly, increased pressure in the right atrium 5 may push the anchor 402 and / or atrial septum 101 towards the left atrium 2, causing the tether(s) to become taught and / or pulling the inner wall 414 and / or covering 406 away from the hepatic veins 9 to remove and / or mitigate occlusion of the hepatic veins 9 and / or other blood vessels.

[0047] As shown in Figure 4B-2, the anchor 402 may be configured to expand and / or compress in response to pressure changes in the left atrium 2 and / or right atrium 5. In some examples, the anchor 402 may be fluid- fdled and / or may be configured to contain a fluid and / or gas. For example, the anchor 402 may be configured to be filled with saline and / or other substance that may be exchanged between the anchor 402, the stent 404 (e.g., a fluid balloon at the stent 404), and / or the tether 405. For example, the tether(s) 405 may comprise one or more tubes configured to receive and / or transfer fluid between ends of the tether(s). In some examples, pressure decrease in the left atrium 2 may cause fluid to enter the anchor and / or may cause a distal wall 407 of the anchor 402 to move away from the atrial septum 101 and / or away from a default distal wall position 433. Similarly, increased pressure in the left atrium 2 may press fluid out of the anchor 402 and / or into the tether(s) 405 and / or the distal wall 407 may move towards the atrial septum 101 and / or towards the default distal wall position 433.

[0048] The anchor 402 may comprise a balloon and / or drum. In some examples, the distal wall 407 of the anchor 402 may have a generally flexible and / or elastic structure and / or may be configured to flex, bend, and / or move in response to fluid changes within the anchor 402 and / or pressure changes in the left atrium 2 and / or right atrium 5. Some walls and / or portions of the anchor 402 may be generally rigid. For example, in response to the anchor 402 filling with fluid, only the distal wall 407 may be configured to bend and / or change shape to accommodate the incoming fluid. The anchor 402 may be configured to remain attached to the atrial septum 101 even while the distal wall 407 extends away from the atrial septum 101. As the distal wall 407 extends away from the atrial septum 101, the distal wall 407 may experience tension that may allow the distal wall 407 to elastically recoil and / or return to the default distal wall position 433 as fluid and / or pressure changes relax to allow the anchor 402 to return to the default form.

[0049] Figures 4C and 4D provide isolated views of the stent 404 deployed within the IVC 10 in accordance with one or more examples. Figure 4C illustrates the stent 404 in a relaxed state in which the tether(s) 405 have slack in response to movement of the anchor 402 towards the right atrium 5. In the relaxed state, the inner wall 414 and / or covering 406 may extend towards the outer wall 412 to create occlusion of the hepatic veins. The inner wall 414 may be shape set to the relaxed state.

[0050] Figure 4D illustrates the stent 404 in a modified state in which the tether(s) 405 become taut and pulls the inner wall 414 and / or covering 406 away from the outer wall 412 and / or away from the vessel walls. In some examples, the tether(s) 405 may cinch in a drawstring manner about the inner wall 414 and / or covering 406.

[0051] The tether(s) 405 in Figures 4A-4D and / or in other examples described herein may be sized to extend from the stent 404 and / or various occlusion devices described herein to one or more chambers of a heart 1. In some examples, the tether(s) 405 may provide a fluid connection between the stent 404 and / or other devices (e.g., caval devices) and the one or more chambers of the heart 1. The tether(s) 405 may provide for periodic and / or alternating movement of the stent 404 and / or other device(s) in response to blood pressure changes within the heart 1. For example, blood pressure changes may cause compression, filling, and / or movement of the anchor 402 and / or compression devices disposed at a heart chamber. Such movement, compression, and / or filling may be translated to the stent 404 and / or other device(s) via the tether(s) 405. For example, blood pressure changes in the heart may cause periodic and / or alternating obstruction of one or more lumens of the stent 404 and / or other device(s) via tightening, slackening, and / or transmission of fluids between the stent 404 (or other caval device) and the anchor 402 (or other heart chamber device).

[0052] Figures 5 A and 5B illustrate another example stent 504 for use in a pressure- induced modulation system in accordance with one or more examples. The stent 504 may be attached to one or more tethers 505, which may extend between the stent 504 and an anchor deployed in the left atrium and / or right atrium.

[0053] In some examples, the stent 504 may be disposed at least partially in the IVC 10 and / or right atrium 5. The stent 504 may comprise a frame 503 forming an outer wall 512 and / or an inner wall 514. The stent 504 may also comprise a covering 506 (e.g., skirt) extending at least partially along the frame 503. The covering 506 may be at least partially fluid-tight and / or may be configured to occlude the IVC 10 and / or branching blood vessels 9 (e.g., hepatic veins) while disposed adjacent to and / or in contact with the outer wall 512. The tethers 505 may be configured to pull the covering 506 away from the outer wall 512 and / ortowards the inner wall 514 to reduce and / or prevent occlusion of the IVC 10 and / or branching blood vessels 9 by the covering 506.

[0054] The tether 505 may be configured to harvest deflecting movements of the atrial septum during contractions of the left atrium and / or right atrium. The tether 505 may form a functional connection between the stent 504 and an anchor. The tether 505 can comprise any suitable means for transferring deflection of the septum to the stent 504.

[0055] The stent 504 may be deployed in the IVC 10 and / or can include an outer sealing covering 506 along, for example, an interior portion of the stent 504. In some examples, the covering 506 may attach to and / or extend form a distal end 518 of the stent 504. The stent504 may comprise a frame 503 including an outer wall 512 and / or an inner wall 514 which may be coupled together at the distal end 518 of the stent 504 and / or may be separate at a proximal end 516 of the stent 504.

[0056] The frame 503 may comprise a wire and / or mesh structure. The covering 506 can comprise fabric and / or other suitable materials and / or may be configured to occluding blood flow. In some examples, the covering 506, inner wall 514, and / or outer wall 512 may be biased such that the covering 506 may lay generally flatly against the outer wall 512 to cause occlusion of the hepatic veins 9. In some examples, the inner wall 514 may be configured to bend towards the outer wall 512 (e.g., at the proximal end 516) and / or away from the outer wall 512. For example, the inner wall 514 may be biased to bend into contact with the outer wall 512 to extend the covering 506 (which may be attached to the inner wall) across the hepatic veins 9. The covering 506, inner wall 514, and / or outer wall 512 may be attached to the tethers505 at or near the proximal end 516 of the stent 504. For example, the tethers 505 may be attached the inner wall 514 to pull the inner wall 514 away from the outer wall 512 and / or may be attached to the covering 506 to pull the covering away from the outer wall 512. When there is slack in the tethers 505, the inner wall 514 and / or covering 506 may sag against the outer wall 512. When the tethers 505 are pulled taut, the inner wall 514 and / or covering 506 may be pulled away from the outer wall 512 to allow blood to flow from the hepatic veins 9 into the IVC 10 and / or right atrium 5.

[0057] In some examples, the tether(s) 505 can comprise a lasso-like mechanism configured to cinch the inner wall 514 and / or covering 506 when pulled taut. For example, the tether(s) 505 may form a loop extending circumferentially around the inner wall 514 and / or covering 506. As the tether(s) 505 become taut, the tether(s) 505 may apply force to a full circumference of the inner wall 514 and / or covering 506.

[0058] The stent 504 can comprise a ring 510, which can include a balloon and / or other inflatable device. For example, the ring 510 may be configured to inflate with saline and / or other substance passed to the ring 510 via the tether 505 (e.g., fluid tube). The ring 510 may be attached to the inner wall 514 and / or covering 506. In some examples, the inner wall 514 and / or the covering 506 may be attached to an inner side of the ring 510.

[0059] Figure 5A illustrates the stent 504 in a relaxed and / or expanded state in which the ring 510 is expanded and / or inflated with a fluid in response to low pressure in the right atrium 5 and / or high pressure in the left atrium 2. In the relaxed state, the ring 510 may expand to fill space between the inner wall 514 and the outer wall 512 to occlude blood flow from the hepatic veins 9. The ring 510 may be configured to extend from the inner wall 514 and / or into contact with the outer wall 512 to seal against the vessel walls and / or against the outer wall 512. In some examples, the ring 510 may be configured to press the outer wall 512 outwardly towards the vessel walls.

[0060] Figure 5B illustrates the stent 504 in a deflated and / or modified state in which the ring 510 is deflated and / or fluid has exited the ring 510 via the tether 505 and / or towards an anchor (e.g., disposed in the left atrium 2). For example, increase in pressure in the right atrium 5 and / or decrease in pressure in the left atrium 2 may cause fluid to be pressed into an anchor disposed at a distal end of the tether 505 and / or within the left atrium 2. Deflation of the ring 510 may create openings between the outer wall 512 and the inner wall 514 (and / or the covering 506) to allow blood flow from the hepatic veins 9 to move upwards towards the right atrium 5.

[0061] Figures 6A and 6B illustrate another example pressure-induced modulation system in accordance with one or more examples. The system may comprise a compression device 602 (e.g., anchor) disposed in the left atrium 2 and an occlusion device 614 (e.g., stent) disposed in the SVC 22. However, the occlusion device 614 may additionally or alternatively be disposed at least partially in the IVC 10. The occlusion device 614 can comprise a stent. The term “stent” is used herein in accordance with its plain and ordinary meaning and can refer to any device (e.g., cylindrical device) configured for placement in a blood vessel. The occlusion device 614 can comprise an inner lumen configured to allow blood flow at least partially through the occlusion device 614. The compression device 602 and the occlusion device 614 may be interconnected via a tube 605, which may include any suitable device configured for conveying a piston 607 (e.g., rod, bar, wire, means for conveying force) between the compression device 602 and the occlusion device 614. The term “piston” is used herein in accordance with its plain and ordinary meaning and may include any rod, bar, wire, and / orelongate member configured to extend through the tube 605 and / or between the compression device 602 and the occlusion device 614. The piston 607 may be configured to convey force between the compression device 602 and the occlusion device 614. For example, the compression device 602 may be configured to drive the piston 607 into the occlusion device 614 and / or the occlusion device 614 may be configured to drive the piston 607 into the compression device 602. Figure 6A illustrates a compressed form of the compression device 602, which may cause extension of the piston 607 to block an opening 611 of the occlusion device 614. Figure 6B illustrates a relaxed form of the compression device 602, which may allow blood flow in the SVC 22 to press the piston 607 away from the opening 611 and / or extend the piston 607 further into the compression device 602.

[0062] The piston 607 may comprise a head 609 at a distal end of the piston 607. The head 609 may have a larger width relative to other portions of the piston 607. The head 609 may be movable towards and / or away from the occlusion device 614. For example, the compression device 602 may be configured to compress in response to high pressure in the left atrium 2 and / or compression of the compression device 602 may cause movement of the piston 607 towards the occlusion device 614. When the piston 607 moves towards the occlusion device 614, the head 609 may be configured to seal an opening 611 of the occlusion device 614 and / or prevent blood from flowing through the SVC 22 into the right atrium 5. As a result, blood flow from the IVC into the right atrium 5 may increase and / or the compression device 602 may relax and / or spring back, thus pulling the piston 607 away from the opening 611 to allow blood flow from the SVC 22 into the right atrium 5. Increased blood flow to the right atrium 5 from the IVC 10 caused by occlusion of the SVC 22 may lead to reduction of renal venous pressure. In some examples, movement of the septal wall 101 may cause movement of the compression device 602 and / or of the piston 607 towards and / or away from the occlusion device 614, thus opening and / or closing the opening 611.

[0063] The opening 611 of the occlusion device 614 may form a constricted neck that may be narrower than other portions of the inner lumen of the occlusion device 614. The head 609 may be sized to fit into a body portion 613 of the occlusion device 614 while sized not to fit into the opening 611 of the occlusion device 614. The opening 611 may form a cylindrical cavity at a proximal and / or distal end of the occlusion device 614 to allow reduced blood flow relative to other end(s) of the occlusion device 614.

[0064] In some examples, the compression device 602 may comprise a spring and / or spring-like mechanism configured to facilitate expansion of the compression device 602 in response to a decrease of pressure in the left atrium 2. The compression device 602 may bebiased to the relaxed and / or free configuration illustrated in Figure 6B. The compression device 602 may have a spring-constant such that when the pressure inside the left atrium 2 exceeds a certain threshold, the compression device 602 may be compressed, moving the piston 607 until the head 609 of the piston 607 seals (or at least significantly constricts) the opening 611.

[0065] The piston 607 may comprise flexible push wire and / or rod. In some examples, at least a portion of the piston 607 may be encased and / or enclosed by a flexible tube 605. The piston may be activated and / or extended by movement of the compression device 602. A relatively large surface area of the compression device 602 may serve to magnify the force compared to the smaller-dimensioned piston 607, transmitting the force by the piston 607. In some examples, activation of the piston 607 can be carried out by hydraulic transmission of internal fluid between the compression device 602 and the piston 607.

[0066] When pressure in the left atrium 2 is sufficiently decreased to a value below the threshold required to keep the compression device 602 compressed, the compression device 602 may be configured to spring and / or relax back to its extended free state, pulling the piston 607 therewith and exposing the opening 611 to renew flow from the SVC 22 into the right atrium 5, and the process can repeatedly cycle between these states in response to left atrial pressure.

[0067] In some examples, elevated SVC 22 pressure can also push the piston 607 to uncover the opening 611 to initiate blood flow and / or push the compression device 602 to the initial open state of Figure 6B. The piston 607 may be small relative to the SVC 22, thus the forces acting against the piston 607 may be relatively low and / or may require high SVC 22 pressure values to be reached to open the piston 607.

[0068] In some examples, the compression device 602 can comprise a locking mechanism to maintain the compression device 602 in the expanded form of Figure 6B until a significant reduction of SVC 22 and / or right atrium 5 pressure is reached prior to removing the head 609 from the opening 611. The piston can be configured to open in a differential manner and / or responsive to changes in pressure in the SVC 22 and / or right atrium 5, such that the piston 607 can be partially closed or open in relation to the pressure value. The occlusion device 614 can comprise a body portion 613 which may be semi-occluded at normal conditions.

[0069] In adults, SVC 22 flow can account for approximately 30% of total venous flow into the heart 1, which can increase to over 50% with hypoxia, hypotension, and / or cardiac dysfunction. In valves (such as the aortic or mitral valves), effective orifice area (EOA) higher than 1.5cm2(150mm2) may be considered to be non-restrictive, and stenosis usually occurs when EOA is lower than this cut-off value. Thus, an open area of the body portion 613 higherthan 150mm2may not inflict symptoms, particularly when the SVC 22 flow is in the range of about 30-50% of the total venous flow.

[0070] Since flow depends on the area and flow velocity, and assuming that the flow through the SVC 22 is about half of the total flow, an EOA of at least 75mm2may be clinically acceptable. Thus, given that typical SVC 22 diameter is approximately 20mm, a passage hole having a diameter of approximately 10mm can have an EOA which may be greater than 75mm2, which may be clinically sufficient for the SVC 22.

[0071] In some examples, the compression device 602, occlusion device 614, and / or other components of the system may be delivered and / or deployed via a catheter and / or minimally invasive approach and / or may have a relatively low profile. In some examples, the compression device 602 and / or occlusion device 614 may be crimpable and / or at least partially flexible.

[0072] The system may be at least partially hemodynamically compatible / compliant and / or may not overly restrict blood flow and / or can avoid risks of promoting thrombus formation and hemolysis. For example, the components of the system can have rounded comers and / or smooth material surfaces and / or can be made from hemocompatible materials.

[0073] The system can comprise any suitable components for selectively occluding the SVC 22 and / or other blood vessel. For example, the occlusion device 614 can comprise a mechanical cam that can close a small door and / or hinge (similar to a leaflet). In some examples, the piston 607 may not be located at a center of the blood stream but rather may be positioned at a side of the blood vessel to reduce interaction with central blood flow. In some examples, the occlusion device 614 can comprise two cones and / or similar mechanisms having holes and / or apertures. The cones may be movable relative to each other and / or configured to close a blood flow passage when contacting each other.

[0074] The compression device 602 may be secured to the septum 101 in any suitable manner. In some examples, a support anchor 606 may be configured to anchor the compression device 602 in place. The anchor 606 may comprise a generally solid and / or hollow structure configured to be disposed opposite the compression device 602 in the right atrium 5 and / or against the septum 101 on the right atrium 5 side. At least a portion of the septum 101 may be sandwiched between the anchor 606 and the compression device 602. In some examples, the anchor 606 may comprise an inflatable balloon and / or other expandable device. The anchor 606 may be connected to the compression device 602 and / or may be an extension of the compression device 602. Alternatively, the anchor 606 may be a separate device and / ormay be joined to the compression device 602 via the tube 605 and / or other tethering device. In some examples, the anchor 606 may comprise a disc and / or similar device and / or may have a generally circular and / or ring-shaped form.

[0075] In some examples, the tube 605 and / or piston 607 may be configured to extend at least partially through the anchor 606 and / or through the septum 101 as the piston 607 extends from the compression device 602 towards the SVC 22. The anchor 606 and / or compression device 602 may comprise apertures and / or openings configured to receive and / or accommodate the tube 605 and / or piston 607.

[0076] The occlusion device 614 may be delivered into the heart 1 separately and / or together with the compression device 602. In some examples, the occlusion device 614 may have a generally cylindrical form and / or may be configured to approximate a cross-sectional shape of the SVC 22. The tube 605 and / or piston 607 may have a suitable length.

[0077] The compression device 602, occlusion device 614, and / or anchor 606 may have any suitable structure. In some examples, the compression device 602 and / or anchor 606 may comprise an outer layer and / or an inner layer. The inner layer may comprise a generally flexible, stretchy, and / or elastic material, which can include rubber, latex, and / or similar materials. The outer layer may have a generally rigid and / or bendable structure and / or may comprise one or more interwoven wires and / or lines of material. The outer layer may be at least partially composed of Nitinol and / or other shape memory alloys.

[0078] The compression device 602 and / or anchor 606 may be configured to be filled with an incompressible fluid. In some examples, the compression device 602, anchor 606, and / or occlusion device 614 may be implanted through an endovascular transeptal approach.

[0079] In some examples, the compression device 602 may comprise various features configured to regulate inflation and / or deflation and / or to regulate a rate of inflation and / or deflation of the compression device 602. For example, one or more springs, coils, and / or similar elements (e.g., Nitinol wire forms) may be attached to an exterior of the compression device 602 and / or may be placed inside the compression device 602 to regulate the rate of deflation and / or inflation.

[0080] While Figures 6A and 6B illustrate an occlusion device 614 in an SVC 22, systems may include multiple occlusion devices and / or similar devices. For example, the occlusion device 614 may be used in series with one or more devices disposed in an IVC 10. In some examples, the occlusion device 614 (and / or other occlusion devices described herein) may be placed in the SVC 22 while a second device (e.g., the stent 404 of Figure 4 A) may beplaced in the IVC 10 to further promote blood flow into the right atrium 5 via the IVC 10. Multiple devices may be coupled to and / or connected to the compression device 602 and / or various anchors described herein that may be disposed at the left atrium 2, right atrium 5, and / or other chamber of the heart 1.

[0081] Figures 7A and 7B illustrate another example pressure-induced modulation system in accordance with one or more examples. The system may comprise a compression device 702 (e.g., anchor) disposed in the left atrium 2 and an occlusion device 714 disposed in the SVC 22 and / or IVC 10. The compression device 702 and the occlusion device 714 may be interconnected via a tube 705, which may include any suitable device configured for conveying a piston 707 (e.g., rod, bar, wire, means for conveying force) between the compression device 702 and the occlusion device 714. The piston 707 may be configured to convey force between the compression device 702 and the occlusion device 714. For example, the compression device 702 may be configured to drive the piston 707 into the occlusion device 714 and / or the occlusion device 714 may be configured to drive the piston 707 into the compression device 702. Figure 7A illustrates a compressed form of the compression device 702, which may cause extension of the piston 707 to block an opening 711 of the occlusion device 714. Figure 7B illustrates a relaxed form of the compression device 702, which may allow blood flow in the SVC 22 to press the piston 707 away from the opening 711 and / or extend the piston 707 further into the compression device 702.

[0082] The piston 707 may comprise a head 709 at a distal end of the piston 707. The head 709 may have a larger width relative to other portions of the piston 707. The head 709 may be movable towards and / or away from the occlusion device 714. For example, the compression device 702 may be configured to compress in response to high pressure in the left atrium 2 and / or compression of the compression device 702 may cause movement of the piston 707 towards the occlusion device 714. When the piston 707 moves towards the occlusion device 714, the head 709 may be configured to seal an opening 711 of the occlusion device 714 and / or prevent blood from flowing through the SVC 22 into the right atrium 5. As a result, blood flow from the IVC into the right atrium 5 may increase and / or the compression device 702 may relax and / or spring back, thus pulling the piston 707 away from the opening 711 to allow blood flow from the SVC 22 into the right atrium 5. Increased blood flow to the right atrium 5 from the IVC 10 caused by occlusion of the SVC 22 may lead to reduction of renal venous pressure.

[0083] In some examples, the compression device 702 may comprise a spring and / or spring-like mechanism configured to facilitate expansion of the compression device 702in response to a decrease of pressure in the left atrium 2. The compression device 702 may be biased to the relaxed and / or free configuration illustrated in Figure 7B. The compression device 702 may have a spring-constant such that when the pressure inside the left atrium 2 exceeds a certain threshold, the compression device 702 may be compressed, moving the piston 707 until the head 709 of the piston 707 seals (or at least significantly constricts) the opening 711.

[0084] The piston 707 may comprise flexible push wire and / or rod. In some examples, at least a portion of the piston 707 may be encased and / or enclosed by a flexible tube 705. The piston may be activated and / or extended by movement of the compression device 702. A relatively large surface area of the compression device 702 may serve to magnify the force compared to the smaller-dimensioned piston 707, transmitting the force by the piston 707. In some examples, activation of the piston 707 can be carried out by hydraulic transmission of internal fluid between the compression device 702 and the piston 707.

[0085] When pressure in the left atrium 2 is sufficiently decreased to a value below the threshold required to keep the compression device 702 compressed, the compression device 702 may be configured to spring and / or relax back to its extended free state, pulling the piston 707 therewith and exposing the opening 711 to renew flow from the SVC 22 into the right atrium 5, and the process can repeatedly cycle between these states in response to left atrial pressure.

[0086] In some examples, elevated SVC 22 pressure can also push the piston 707 to uncover the opening 711 to initiate blood flow and / or push the compression device 702 to the initial open state of Figure 7B. The piston 707 may be small relative to the SVC 22, thus the forces acting against the piston 707 may be relatively low and / or may require high SVC 22 pressure values to be reached to open the piston 707.

[0087] In some examples, the compression device 702 can comprise a locking mechanism to maintain the compression device 702 in the expanded form of Figure 7B until a significant reduction of SVC 22 and / or right atrium 5 pressure is reached prior to removing the head 709 from the opening 711. The piston can be configured to open in a differential manner and / or responsive to changes in pressure in the SVC 22 and / or right atrium 5, such that the piston 707 can be partially closed or open in relation to the pressure value. The occlusion device 714 can comprise a body portion 713 which may be semi-occluded at normal conditions.

[0088] The system can comprise any suitable components for selectively occluding the SVC 22 and / or other blood vessel. For example, the occlusion device 714 can comprise a mechanical cam that can close a small door and / or hinge (similar to a leaflet). In some examples, the piston 707 may not be located at a center of the blood stream but rather may bepositioned at a side of the blood vessel to reduce interaction with central blood flow. In some examples, the occlusion device 714 can comprise two cones and / or similar mechanisms having holes and / or apertures. The cones may be movable relative to each other and / or configured to close a blood flow passage when contacting each other.

[0089] The compression device 702 may be secured to the septum 101 in any suitable manner. In some examples, a support anchor 706 may be configured to anchor the compression device 702 in place. The anchor 706 may comprise a generally solid and / or hollow structure configured to be disposed opposite the compression device 702 in the right atrium 5 and / or against the septum 101 on the right atrium 5 side. At least a portion of the septum 101 may be sandwiched between the anchor 706 and the compression device 702. In some examples, the anchor 706 may comprise an inflatable balloon and / or other expandable device. The anchor 706 may be connected to the compression device 702 and / or may be an extension of the compression device 702. Alternatively, the anchor 706 may be a separate device and / or may be joined to the compression device 702 via the tube 705 and / or other tethering device. In some examples, the anchor 706 may comprise a disc and / or similar device and / or may have a generally circular and / or ring-shaped form.

[0090] In some examples, the tube 705 and / or piston 707 may be configured to extend at least partially through the anchor 706 and / or through the septum 101 as the piston 707 extends from the compression device 702 towards the SVC 22. The anchor 706 and / or compression device 702 may comprise apertures and / or openings configured to receive and / or accommodate the tube 705 and / or piston 707.

[0091] The occlusion device 714 may be delivered into the heart 1 separately and / or together with the compression device 702. In some examples, the occlusion device 714 may have a generally cylindrical form and / or may be configured to approximate a cross-sectional shape of the SVC 22. The tube 705 and / or piston 707 may have a suitable length.

[0092] The compression device 702, occlusion device 714, and / or anchor 706 may have any suitable structure. In some examples, the compression device 702 and / or anchor 706 may comprise an outer layer and / or an inner layer. The inner layer may comprise a generally flexible, stretchy, and / or elastic material, which can include rubber, latex, and / or similar materials. The outer layer may have a generally rigid and / or bendable structure and / or may comprise one or more interwoven wires and / or lines of material. The outer layer may be at least partially composed of Nitinol and / or other shape memory alloys.

[0093] The compression device 702 and / or anchor 706 may be configured to be filled with an incompressible fluid. In some examples, the compression device 702, anchor706, and / or occlusion device 714 may be implanted through an endovascular transeptal approach.

[0094] In some examples, the compression device 702 may comprise various features configured to regulate inflation and / or deflation and / or to regulate a rate of inflation and / or deflation of the compression device 702. For example, one or more springs, coils, and / or similar elements (e.g., Nitinol wire forms) may be attached to an exterior of the compression device 702 and / or may be placed inside the compression device 702 to regulate the rate of deflation and / or inflation.

[0095] Figures 8A and 8B illustrate another example pressure-induced modulation system in accordance with one or more examples. The system may comprise a compression device 802 (e.g., anchor) disposed in the left atrium 2 and an occlusion device 814 disposed in the SVC 22 and / or IVC 10. The compression device 802 and the occlusion device 814 may be interconnected via an outer tube 805, which may include any suitable device configured for conveying and / or sealing an inner tube 817 (e.g., means for conveying gas and / or fluid) between the compression device 802 and the occlusion device 814. The inner tube 817 may be configured to convey gas and / or fluid between the compression device 802 and the occlusion device 814. For example, the compression device 802 may be configured to drive gas and / or fluid into the inner tube 817 and / or into a balloon 819 (e.g., inflation and / or inflatable device) disposed at a distal end of the inner tube 817. Figure 8A illustrates a compressed form of the compression device 802, which may cause inflation of the balloon 819, which may in turn block and / or occlude an opening 811 of the occlusion device 814. Figure 8B illustrates a relaxed form of the compression device 802, in which the balloon 819 may at least partially deflate to allow at least partial blood flow through the opening 811. The occlusion device 814 may comprise a support member (e.g., arm, tube, bowl) configured to position the balloon 819 at or aligned with the opening 811.

[0096] The balloon 819 may be configured to inflate to a width and / or diameter that is greater than a corresponding width and / or diameter of the opening 811. Moreover, the balloon 819 may be configured to extend at least partially towards the opening 811 as the balloon 819 inflates. The compression device 802 may be configured to compress in response to high pressure in the left atrium 2 and / or compression of the compression device 802 may cause movement of gas and / or fluid from the compression device 802 into the balloon 819 via the inner tube 817. When the balloon 819 inflates with gas and / or fluid, the balloon 819 may be configured to seal an opening 811 of the occlusion device 814 and / or prevent blood from flowing through the SVC 22 into the right atrium 5. As a result, blood flow from the IVC intothe right atrium 5 may increase and / or the compression device 802 may relax and / or spring back, thus pulling gas and / or fluid from the balloon 819 to allow blood flow from the SVC 22 into the right atrium 5.

[0097] In some examples, the compression device 802 may comprise a spring and / or spring-like mechanism configured to facilitate expansion of the compression device 802 in response to a decrease of pressure in the left atrium 2. The compression device 802 may be biased to the relaxed and / or free configuration illustrated in Figure 8B. The compression device 802 may have a spring-constant such that when the pressure inside the left atrium 2 exceeds a certain threshold, the compression device 802 may be compressed, inflating the balloon 819 until the balloon 819 seals (or at least significantly constricts) the opening 811. Expansion of the compression device 802 may be configured to cause suction through the inner tube 817 and / or may pull gas and / or fluid from the balloon 819 to cause deflation of the balloon 819.

[0098] In some examples, at least a portion of the inner tube 817 may be encased and / or enclosed by an outer tube 805. In some examples, elevated SVC 22 pressure can also push gas and / or fluid out of the balloon 819 and / or into the inner tube 817 to uncover the opening 811 to initiate blood flow and / or push the compression device 802 to the initial open state of Figure 8B.

[0099] In some examples, the compression device 802 can comprise a locking mechanism to maintain the compression device 802 in the expanded form of Figure 8B until a significant reduction of SVC 22 and / or right atrium 5 pressure is reached prior to suctioning gas and / or fluid from the balloon 819. The balloon 819 can be configured to inflate and / or deflate in a differential manner and / or responsive to changes in pressure in the SVC 22 and / or right atrium 5, such that the balloon 819 can be inflated and / or deflated in relation to the pressure value. The occlusion device 814 can comprise a body portion 813 which may be semioccluded at normal conditions. The occlusion device 814 may comprise a support member 818 (e.g., arm and / or tube) configured to guide and / or align the balloon 819 and / or piston (see, e.g., Figures 6-7) with the opening 811.

[0100] The system can comprise any suitable components for selectively occluding the SVC 22 and / or other blood vessel. For example, the occlusion device 814 can comprise a mechanical cam that can close a small door and / or hinge (similar to a leaflet). In some examples, the inner tube 817 and / or balloon 819 may not be located at a center of the blood stream but rather may be positioned at a side of the blood vessel to reduce interaction with central blood flow.

[0101] The compression device 802 may be secured to the septum 101 in any suitable manner. In some examples, a support anchor 806 may be configured to anchor the compression device 802 in place. The anchor 806 may comprise a generally solid and / or hollow structure configured to be disposed opposite the compression device 802 in the right atrium 5 and / or against the septum 101 on the right atrium 5 side. At least a portion of the septum 101 may be sandwiched between the anchor 806 and the compression device 802. In some examples, the anchor 806 may comprise an inflatable balloon and / or other expandable device. The anchor 806 may be connected to the compression device 802 and / or may be an extension of the compression device 802. Alternatively, the anchor 806 may be a separate device and / or may be joined to the compression device 802 via the outer tube 805 and / or other tethering device. In some examples, the anchor 806 may comprise a disc and / or similar device and / or may have a generally circular and / or ring-shaped form.

[0102] In some examples, the outer tube 805 and / or inner tube 817 may be configured to extend at least partially through the anchor 806 and / or through the septum 101. The anchor 806 and / or compression device 802 may comprise apertures and / or openings configured to receive and / or accommodate the outer tube 805 and / or inner tube 817.

[0103] The occlusion device 814 may be delivered into the heart 1 separately and / or together with the compression device 802. In some examples, the occlusion device 814 may have a generally cylindrical form and / or may be configured to approximate a cross-sectional shape of the SVC 22. The outer tube 805 and / or inner tube 817 may have a suitable length.

[0104] The compression device 802, occlusion device 814, and / or anchor 806 may have any suitable structure. In some examples, the compression device 802 and / or anchor 806 may comprise an outer layer and / or an inner layer. The inner layer may comprise a generally flexible, stretchy, and / or elastic material, which can include rubber, latex, and / or similar materials. The outer layer may have a generally rigid and / or bendable structure and / or may comprise one or more interwoven wires and / or lines of material. The outer layer may be at least partially composed of Nitinol and / or other shape memory alloys.

[0105] The compression device 802, balloon 819, and / or anchor 806 may be configured to be filled with an incompressible fluid. In some examples, the compression device 802, anchor 806, and / or occlusion device 814 may be implanted through an endovascular transeptal approach.

[0106] In some examples, the compression device 802 may comprise various features configured to regulate inflation and / or deflation and / or to regulate a rate of inflation and / or deflation of the compression device 802. For example, one or more springs, coils, and / orsimilar elements (e.g., Nitinol wire forms) may be attached to an exterior of the compression device 802 and / or may be placed inside the compression device 802 to regulate the rate of deflation and / or inflation.

[0107] Figures 9A and 9B illustrate another example pressure-induced modulation system in accordance with one or more examples. The system may comprise a compression device 902 (e.g., anchor) disposed in the left atrium 2 and an occlusion device 914 disposed in the SVC and / or IVC. The compression device 902 and the occlusion device 914 may be interconnected via an outer tube 905, which may include any suitable device configured for conveying and / or sealing an inner tube 917 (e.g., means for conveying gas and / or fluid) between the compression device 902 and the occlusion device 914. The inner tube 917 may be configured to convey gas and / or fluid between the compression device 902 and the occlusion device 914. For example, the compression device 902 may be configured to drive gas and / or fluid into the inner tube 917 and / or into a balloon 919 (e.g., inflation and / or inflatable device) disposed at a distal end of the inner tube 917. Figure 9A illustrates a compressed form of the compression device 902, which may cause inflation of the balloon 919, which may in turn block and / or occlude an opening 911 of the occlusion device 914. Figure 9B illustrates a relaxed form of the compression device 902, in which the balloon 919 may at least partially deflate to allow at least partial blood flow through the opening 911. The occlusion device 914 may comprise a support member 918 (e.g., arm and / or tube) configured to guide and / or align the balloon 919 with the opening 911.

[0108] The balloon 919 may be configured to inflate to a width and / or diameter that is greater than a corresponding width and / or diameter of the opening 911. Moreover, the balloon 919 may be configured to extend at least partially towards the opening 911 as the balloon 919 inflates. The compression device 902 may be configured to compress in response to high pressure in the left atrium 2 and / or compression of the compression device 902 may cause movement of gas and / or fluid from the compression device 902 into the balloon 919 via the inner tube 917. When the balloon 919 inflates with gas and / or fluid, the balloon 919 may be configured to seal an opening 911 of the occlusion device 914 and / or prevent blood from flowing through the SVC 22 into the right atrium 5. As a result, blood flow from the IVC into the right atrium 5 may increase and / or the compression device 902 may relax and / or spring back, thus pulling gas and / or fluid from the balloon 919 to allow blood flow from the SVC 22 into the right atrium 5.

[0109] In some examples, the compression device 902 may comprise a spring and / or spring-like mechanism configured to facilitate expansion of the compression device 902in response to a decrease of pressure in the left atrium 2. The compression device 902 may be biased to the relaxed and / or free configuration illustrated in Figure 9B. The compression device 902 may have a spring-constant such that when the pressure inside the left atrium 2 exceeds a certain threshold, the compression device 902 may be compressed, inflating the balloon 919 until the balloon 919 seals (or at least significantly constricts) the opening 911. Expansion of the compression device 902 may be configured to cause suction through the inner tube 917 and / or may pull gas and / or fluid from the balloon 919 to cause deflation of the balloon 919.

[0110] In some examples, at least a portion of the inner tube 917 may be encased and / or enclosed by an outer tube 905. In some examples, elevated SVC 22 pressure can also push gas and / or fluid out of the balloon 919 and / or into the inner tube 917 to uncover the opening 911 to initiate blood flow and / or push the compression device 902 to the initial open state of Figure 9B.

[0111] In some examples, the compression device 902 can comprise a locking mechanism to maintain the compression device 902 in the expanded form of Figure 9B until a significant reduction of SVC 22 and / or right atrium 5 pressure is reached prior to suctioning gas and / or fluid from the balloon 919. The balloon 919 can be configured to inflate and / or deflate in a differential manner and / or responsive to changes in pressure in the SVC 22 and / or right atrium 5, such that the balloon 919 can be inflated and / or deflated in relation to the pressure value. The occlusion device 914 can comprise a body portion 913 which may be semioccluded at normal conditions.

[0112] The system can comprise any suitable components for selectively occluding the SVC 22 and / or other blood vessel. For example, the occlusion device 914 can comprise a mechanical cam that can close a small door and / or hinge (similar to a leaflet). In some examples, the inner tube 917 and / or balloon 919 may not be located at a center of the blood stream but rather may be positioned at a side of the blood vessel to reduce interaction with central blood flow.

[0113] The compression device 902 may be secured to the septum 101 in any suitable manner. In some examples, a support anchor 906 may be configured to anchor the compression device 902 in place. The anchor 906 may comprise a generally solid and / or hollow structure configured to be disposed opposite the compression device 902 in the right atrium 5 and / or against the septum 101 on the right atrium 5 side. At least a portion of the septum 101 may be sandwiched between the anchor 906 and the compression device 902. In some examples, the anchor 906 may comprise an inflatable balloon and / or other expandable device. The anchor 906 may be connected to the compression device 902 and / or may be an extensionof the compression device 902. Alternatively, the anchor 906 may be a separate device and / or may be joined to the compression device 902 via the outer tube 905 and / or other tethering device. In some examples, the anchor 906 may comprise a disc and / or similar device and / or may have a generally circular and / or ring-shaped form.

[0114] In some examples, the outer tube 905 and / or inner tube 917 may be configured to extend at least partially through the anchor 906 and / or through the septum 101. The anchor 906 and / or compression device 902 may comprise apertures and / or openings configured to receive and / or accommodate the outer tube 905 and / or inner tube 917.

[0115] The occlusion device 914 may be delivered into the heart 1 separately and / or together with the compression device 902. In some examples, the occlusion device 914 may have a generally cylindrical form and / or may be configured to approximate a cross-sectional shape of the SVC 22. The outer tube 905 and / or inner tube 917 may have a suitable length.

[0116] The compression device 902, occlusion device 914, and / or anchor 906 may have any suitable structure. In some examples, the compression device 902 and / or anchor 906 may comprise an outer layer and / or an inner layer. The inner layer may comprise a generally flexible, stretchy, and / or elastic material, which can include rubber, latex, and / or similar materials. The outer layer may have a generally rigid and / or bendable structure and / or may comprise one or more interwoven wires and / or lines of material. The outer layer may be at least partially composed of Nitinol and / or other shape memory alloys.

[0117] The compression device 902, balloon 919, and / or anchor 906 may be configured to be filled with an incompressible fluid. In some examples, the compression device 902, anchor 906, and / or occlusion device 914 may be implanted through an endovascular transeptal approach.

[0118] In some examples, the compression device 902 may comprise various features configured to regulate inflation and / or deflation and / or to regulate a rate of inflation and / or deflation of the compression device 902. For example, one or more springs, coils, and / or similar elements (e.g., Nitinol wire forms) may be attached to an exterior of the compression device 902 and / or may be placed inside the compression device 902 to regulate the rate of deflation and / or inflation.

[0119] Figure 10 provides a flowchart illustrating a process 1000 for modulating and / or regulating blood flow within a heart in accordance with one or more examples. Steps of the process 1000 can be performed in any reasonable order.

[0120] At a step 1002, the process 1000 involves advancing a delivery system (e.g., a catheter) percutaneously and / or surgically into a heart and / or at or near a right atrium of aheart. For example, the delivery system may be delivered into the left atrium and / or right atrium. The delivery system may be configured to carry and / or deploy one or more anchors (e.g., compression devices), occlusion devices, and / or tethers (e.g., sutures, tubes, etc.).

[0121] At a step 1004, the process 1000 involves deploying and / or placing an anchor at or near the atrial septum. In some examples, at least a portion of the anchor may be deployed within the left atrium (e.g., at a left atrium side of an atrial septum). The anchor may comprise one or more portions configured to extend through the atrial septum and / or configured to be deployed at the right atrium side of the atrial septum.

[0122] The anchor can comprise a pledget and / or fillable and / or inflatable device (e.g., compression device). In some examples, the compression device can comprise a piston configured to extend out of a fillable portion of the compression device and / or through a tether (e.g., tube) coupled to the compression device. The compression device may be configured to convey gas, fluid, and / or a piston out of the compression device and / or towards an occlusion device. In some examples, the anchor may be configured to move (e.g., laterally) with the atrial septum during cardiac cycles (e.g., towards and / or away from the IVC and / or SVC). The anchor may be configured to move (e.g., expand / inflate and / or compress / deflate) in response to pressure changes in the heart.

[0123] At a step 1006, the process 1000 involves deploying and / or placing an occlusion device at least partially in the IVC and / or SVC. In some examples, the occlusion device may be configured to extend at least partially into the right atrium. The occlusion device can comprise a stent and / or similar device configured to selectively occlude and / or allow blood flow through the IVC and / or SVC and / or one or more branching blood vessels. In some examples, the occlusion device can comprise a skirt and / or covering configured to selectively occlude openings (e.g., cells) of a frame of the occlusion device. The occlusion device may comprise one or more openings into a lumen of the occlusion device.

[0124] At a step 1008, the process involves tethering the anchor to the occlusion device to translate movement of the anchor to movement and / or occlusion at the occlusion device. For example, one or more tubes, sutures, and / or lines may be configured to interconnect the anchor and the occlusion device. In some examples, a tether interconnecting the anchor and the occlusion device may be configured to convey gas, fluid, and / or mechanical elements between the anchor and the occlusion device. The tether, anchor, and / or occlusion device can comprise and / or be used in combination with one or more pistons, inner tubes, and / or outer tubes. Example tethers can be configured to translate movement harvested at the anchor to the occlusion device. For example, a tether (e.g., outer tube) may be configured to convey gasand / or fluid pushed out of and / or suctioned from the anchor (e.g., compression device) and / or pushed out of and / or suctioned from the occlusion device via an inner tube. In another example, a tether (e.g., outer tube) may be configured to convey a piston comprising a head portion, which may be pressed towards the occlusion device to occlude an opening of the occlusion device and / or which may be pressed towards the anchor to open the opening of the occlusion device. In some examples, a tether may comprise one or more sutures configured to slacken and / or become taut in response to movement (e.g., lateral movement) of the anchor to selectively cinch and / or relax a skirt and / or covering of the occlusion device.

[0125] Described herein are various example medical implants and / or delivery methods. Some examples described herein may be used in combination and / or may be used independently.

[0126] Example 1 : A system comprising: an anchor configured for placement at an atrial septum of a heart; a stent configured for placement in a blood vessel of the heart and comprising an inner lumen; and a tether coupled to the anchor and the stent, wherein movement of the anchor is translated to movement at the stent via the tether.

[0127] Example 2: The system of any example herein, in particular example 1, wherein the anchor is configured to move with the atrial septum.

[0128] Example 3: The system of any example herein, in particular example 1, wherein the tether is configured to become slack or become taut in response to movement of the anchor.

[0129] Example 4: The system of any example herein, in particular example 1, wherein the stent comprises: an outer wall comprising one or more open cells; an inner wall; and a skirt configured to extend at least partially along the inner wall.

[0130] Example 5: The system of any example herein, in particular example 4, wherein the inner wall is shape-set to extend towards the outer wall at a proximal end of the inner wall.

[0131] Example 6: The system of any example herein, in particular example 4, wherein the tether is configured to become taut to pull the inner wall away from the outer wall and mitigate obstruction of the one or more open cells of the outer wall.

[0132] Example 7: The system of any example herein, in particular example 4, wherein the tether forms a loop around the inner wall.

[0133] Example 8: The system of any example herein, in particular example 1, wherein the anchor is configured for placement at least partially in a left atrium.

[0134] Example 9: The system of any example herein, in particular example 8, wherein the anchor is configured to extend at least partially into a right atrium.

[0135] Example 10: The system of any example herein, in particular example 1, wherein the anchor is configured to expand and compress in response to blood pressure changes in the heart, and wherein the tether comprises a tube.

[0136] Example 11: The system of any example herein, in particular example 10, further comprising a piston extending at least partially through the tether.

[0137] Example 12: The system of any example herein, in particular example 11, wherein compression of the anchor is configured to press the piston against an opening into the inner lumen of the stent.

[0138] Example 13: The system of any example herein, in particular example 11, wherein expansion of the anchor is configured to pull the piston away from an opening into the inner lumen of the stent.

[0139] Example 14: The system of any example herein, in particular example 11, wherein the piston comprises a head portion and a body portion, the head portion having a greater width relative to the body portion.

[0140] Example 15: The system of any example herein, in particular example 10, further comprising an inner tube extending at least partially through the tether, the inner tube comprising a balloon at a distal end of the inner tube.

[0141] Example 16: The system of any example herein, in particular example 15, wherein compression of the anchor is configured to convey a gas or fluid from the anchor to the balloon via the inner tube.

[0142] Example 17: The system of any example herein, in particular example 15, wherein expansion of the anchor is configured to convey a gas or fluid from the balloon to the anchor.

[0143] Example 18: The system of any example herein, in particular example 15, wherein the balloon is configured to expand in response to receiving gas or fluid to at least partially occlude an opening into the inner lumen of the stent.

[0144] Example 19: A method comprising: percutaneously delivering an anchor to an atrial septum of a heart; percutaneously delivering a stent to an inferior vena cava (IVC) or superior vena cava (SVC) of the heart, the stent comprising an inner lumen; and tethering the anchor to the stent to translate movement of the anchor to occlusion of the inner lumen of the stent.

[0145] Example 20: The method of any example herein, in particular example 19, wherein the stent comprises: an outer wall comprising one or more open cells; an inner wall; and a skirt configured to extend at least partially along the inner wall.

[0146] Example 21: The system of any example herein, in particular example 11, wherein the stent comprises a constricted neck at an end of the stent.

[0147] Example 22: The system of any example herein, in particular example 21, wherein the piston is sized to fit into the stent and is sized not to fit into the constricted neck of the stent.

[0148] Example 23: A system for regulating blood flow within a heart, the system comprising: a stent sized for placement in a blood vessel of the heart and comprising an inner lumen; and a tether coupled to the stent, the tether being sized to extend into a chamber of the heart and cause periodic obstruction of the inner lumen of the stent in response to blood pressure changes within the heart.

[0149] Example 24: The system of any example herein, in particular example 23, wherein the tether comprises a tube in fluid communication with the stent and the chamber of the heart.

[0150] Example 25: The system of any example herein, in particular example 23, further comprising an anchor sized for placement at an atrial septum of a heart, the anchor being coupled to the tether.Additional Embodiments

[0151] Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, may be added, merged, or left out altogether. Thus, in certain embodiments, not all described acts or events are necessary for the practice of the processes.

[0152] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is intended in its ordinary sense and is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and / or steps. Thus, such conditional language is not generally intended to imply that features, elements and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” andthe like are synonymous, are used in their ordinary sense, and are used inclusively, in an open- ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or’' is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is understood with the context as used in general to convey that an item, term, element, etc. may be either X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z to each be present.

[0153] It should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Moreover, any components, features, or steps illustrated and / or described in a particular embodiment herein can be applied to or used with any other embodiment(s). Further, no component, feature, step, or group of components, features, or steps are necessary or indispensable for each embodiment. Thus, it is intended that the scope of the inventions herein disclosed and claimed below should not be limited by the particular embodiments described above but should be determined only by a fair reading of the claims that follow.

[0154] It should be understood that certain ordinal terms (e.g., “first” or “second”) may be provided for ease of reference and do not necessarily imply physical characteristics or ordering. Therefore, as used herein, an ordinal term (e.g., “first,” “second,” “third,” etc.) used to modify an element, such as a structure, a component, an operation, etc., does not necessarily indicate priority or order of the element with respect to any other element, but rather may generally distinguish the element from another element having a similar or identical name (but for use of the ordinal term). In addition, as used herein, indefinite articles (“a” and “an”) may indicate “one or more” rather than “one.” Further, an operation performed “based on” a condition or event may also be performed based on one or more other conditions or events not explicitly recited.

[0155] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning thatis consistent with their meaning in the context of the relevant art and not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0156] Although certain preferred embodiments and examples are disclosed below, inventive subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise herefrom is not limited by any of the particular embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain embodiments; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

[0157] The spatially relative terms “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” and similar terms, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device shown in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations.

[0158] Unless otherwise expressly stated, comparative and / or quantitative terms, such as “less,” “more,” “greater,” and the like, are intended to encompass the concepts of equality. For example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”

[0159] Delivery systems as described herein may be used to position catheter tips and / or catheters to various areas of a human heart. For example, a catheter tip and / or cathetermay be configured to pass from the right atrium into the coronary sinus. However, it will be understood that the description can refer or generally apply to positioning of catheter tips and / or catheters from a first body chamber or lumen into a second body chamber or lumen, where the catheter tips and / or catheters may be bent when positioned from the first body chamber or lumen into the second body chamber or lumen. A body chamber or lumen can refer to any one of a number of fluid channels, blood vessels, and / or organ chambers (e.g., heart chambers). Additionally, reference herein to “catheters,” “tubes,” “sheaths,” “steerable sheaths,” and / or “steerable catheters” can refer or apply generally to any type of elongate tubular delivery device comprising an inner lumen configured to slidably receive instrumentation, such as for positioning within an atrium or coronary sinus, including for example delivery catheters and / or cannulas. It will be understood that other types of medical implant devices and / or procedures can be delivered to the coronary sinus using a delivery system as described herein, including for example ablation procedures, drug delivery and / or placement of coronary sinus leads.

Claims

WHAT IS CLAIMED IS:

1. A system for regulating blood flow, the system comprising: an anchor sized for placement at an atrial septum of a heart; a stent sized for placement in a blood vessel of the heart and comprising an inner lumen; and a tether coupled to the anchor and the stent, wherein movement of the anchor is translated to movement at the stent via the tether.

2. The system of claim 1, wherein the anchor is positioned to move with the atrial septum.

3. The system of claim 1 or claim 2, wherein the tether is sized to become slack or become taut in response to movement of the anchor.

4. The system of claim 1 or claim 2, wherein the stent comprises: an outer wall comprising one or more open cells; an inner wall; and a skirt sized to extend at least partially along the inner wall.

5. The system of claim 4, wherein the inner wall is shape-set to extend towards the outer wall at a proximal end of the inner wall.

6. The system of claim 4, wherein the tether is sized to become taut to pull the inner wall away from the outer wall and mitigate obstruction of the one or more open cells of the outer wall.

7. The system of claim 4, wherein the tether forms a loop around the inner wall.

8. The system of claim 1 or claim 2, wherein the anchor is sized for placement at least partially in a left atrium.

9. The system of claim 8, wherein the anchor is positioned to extend at least partially into a right atrium.

10. A system for regulating blood flow, the system comprising: an anchor sized for placement at an atrial septum of a heart;a stent sized for placement in a blood vessel of the heart and comprising an inner lumen; and a tether coupled to the anchor and the stent, wherein movement of the anchor is translated to movement at the stent via the tether; wherein the anchor is positioned to expand and compress in response to blood pressure changes in the heart, and wherein the tether comprises a tube.

11. The system of claim 10, further comprising a piston extending at least partially through the tether.

12. The system of claim 11, wherein compression of the anchor presses the piston against an opening into the inner lumen of the stent.

13. The system of claim 11 or claim 12, wherein expansion of the anchor pulls the piston away from an opening into the inner lumen of the stent.

14. The system of claim 11 or claim 12, wherein the piston comprises a head portion and a body portion, the head portion having a greater width relative to the body portion.

15. The system of claim 11 or claim 12, wherein the stent comprises a constricted neck at an end of the stent.

16. The system of claim 15, wherein the piston is sized to fit into the stent and is sized not to fit into the constricted neck of the stent.

17. A system for regulating blood flow, the system comprising: an anchor sized for placement at an atrial septum of a heart; a stent sized for placement in a blood vessel of the heart and comprising an inner lumen; a tether coupled to the anchor and the stent, wherein movement of the anchor is translated to movement at the stent via the tether; and an inner tube extending at least partially through the tether, the inner tube comprising a balloon at a distal end of the inner tube.

18. The system of claim 17, wherein compression of the anchor conveys a gas or fluid from the anchor to the balloon via the inner tube.

19. The system of claim 17 or claim 18, wherein expansion of the anchor conveys a gas or fluid from the balloon to the anchor.

20. The system of claim 17 or claim 18, wherein the balloon is flexible to expand in response to receiving gas or fluid to at least partially occlude an opening into the inner lumen of the stent.

21. A system for regulating blood flow within a heart, the system comprising: a stent sized for placement in a blood vessel of the heart and comprising an inner lumen; and a tether coupled to the stent, the tether being sized to extend into a chamber of the heart and cause periodic obstruction of the inner lumen of the stent in response to blood pressure changes within the heart.

22. The system of claim 21, wherein the tether comprises a tube in fluid communication with the stent and the chamber of the heart.

23. The system of claim 21 or claim 22, further comprising an anchor sized for placement at an atrial septum of a heart, the anchor being coupled to the tether.

24. The system of claim 23, wherein the anchor is positioned to move with the atrial septum.

25. The system of claim 23, wherein the tether is sized to become slack or become taut in response to movement of the anchor.

26. The system of claim 23, wherein the stent comprises: an outer wall comprising one or more open cells; an inner wall; and a skirt sized to extend at least partially along the inner wall.

27. The system of claim 26, wherein the inner wall is shape-set to extend towards the outer wall at a proximal end of the inner wall.

28. The system of claim 26, wherein the tether is sized to become taut to pull the inner wall away from the outer wall and mitigate obstruction of the one or more open cells of the outer wall.

29. The system of claim 23, further comprising a piston extending at least partially through the tether.

30. The system of claim 29, wherein compression of the anchor presses the piston against an opening into the inner lumen of the stent.

31. The system of claim 29, wherein expansion of the anchor pulls the piston away from an opening into the inner lumen of the stent.

32. The system of claim 29, wherein the piston comprises a head portion and a body portion, the head portion having a greater width relative to the body portion.

33. The system of claim 29, wherein the stent comprises a constricted neck at an end of the stent.

34. The system of claim 33, wherein the piston is sized to fit into the stent and is sized not to fit into the constricted neck of the stent.