Adjustable shunts and associated systems and methods

Abstract

To provide adjustable shunts and associated systems and methods.SOLUTION: The present technology is directed to adjustable interatrial shunting systems that selectively control blood flow between the left atrium and the right atrium of a patient. Adjustable interatrial devices include a shunting element having an outer surface configured to engage native tissue and an inner surface defining a lumen that enables blood to flow from the left atrium to the right atrium when the system is deployed across the septal wall. The systems can include an actuation assembly for selectively adjusting a geometry of the lumen and / or a geometry of a lumen orifice to control the flow of blood through the lumen.SELECTED DRAWING: Figure 28A

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATION(S) This application claims the benefit of the following pending applications: (a) U.S. Provisional Patent Application No. 62 / 897,943, filed September 9, 2019; (b) U.S. Provisional Patent Application No. 62 / 907,696, filed September 29, 2019; (c) U.S. Provisional Patent Application No. 62 / 907,700, filed September 29, 2019; (d) U.S. Provisional Patent Application No. 62 / 907,698, filed September 29, 2019; (e) U.S. Provisional Patent Application No. 62 / 929,608, filed November 1, 2019; (f) U.S. Provisional Patent Application No. 62 / 959,792, filed January 10, 2020; (g) U.S. Provisional Patent Application No. 62 / 976,665, filed February 14, 2020; (h) U.S. Provisional Patent Application No. 62 / 977,933, filed February 18, 2020; (i) U.S. Provisional Patent Application No. 62 / 994,010, filed March 24, 2020; (j) U.S. Provisional Patent Application No. 63 / 002,050, filed March 30, 2020; (k) U.S. Provisional Patent Application No. 63 / 003,594, filed on April 1, 2020, and (l) U.S. Provisional Patent Application No. 63 / 003,632, filed on April 1, 2020.

[0002] All of the aforementioned applications are incorporated herein by reference in their entirety. Furthermore, the elements and features of the embodiments disclosed in the applications incorporated by reference may be combined with various elements and features disclosed and claimed in the present application.

[0003] The present technology relates generally to implantable medical devices, and more particularly to an implantable interatrial system and associated methods for selectively controlling blood flow between the right and left atria of the heart. [Background technology]

[0004] Heart failure is a medical condition associated with the inability of the heart to efficiently pump blood to the body. Heart failure affects millions of people worldwide and can result from multiple underlying causes, but is commonly associated with myocardial stiffness, myocardial remodeling, and / or abnormal cardiovascular dynamics. Chronic heart failure is a progressive disease that worsens considerably over time. Initially, the body's autonomic nervous system adapts to heart failure by altering the sympathetic and parasympathetic balance. These adaptations, while helpful in the short term, can function to exacerbate the disease in the long term.

[0005] Heart failure (HF) is a medical term that includes both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Both HFpEF and HFrEF have poor prognoses, with 1-year mortality rates of 26% and 22%, respectively, according to an epidemiological study. Despite the high prevalence of HFpEF, options for HFpEF patients are limited. Although pharmacological therapy has been shown to affect mortality in HFrEF patients, there are no similarly effective evidence-based drug therapies to treat HFpEF patients. The current practice is to manage and support patients as their health deteriorates.

[0006] A common symptom in patients with heart failure is elevated left atrial pressure. In the past, clinicians have treated patients with elevated left atrial pressure by creating a shunt between the left and right atria using a blade or balloon septal dehiscence. The shunt decompresses the left atrium (LA) by relieving pressure on the right atrium (RA) and systemic veins. However, over time, the shunt typically closes or decreases in size. More recently, percutaneous interatrial shunt devices have been developed that have been shown to effectively reduce left atrial pressure. However, these percutaneous devices often contain annular passages with fixed diameters, which fail to account for the changing physiology and condition of the patient. For this reason, existing percutaneous shunt devices may have reduced clinical effectiveness after a period of time. Moreover, many existing percutaneous shunt devices are typically only available in a single size, which may work well for one patient but not another. Also, the amount of shunt created during the initial procedure may later be determined to be suboptimal after several months. Thus, there is a need for improved devices, systems, and methods for treating heart failure patients, particularly those with elevated left atrial pressure. Summary of the Invention [Means for solving the problem]

[0007] The present technology is directed to an adjustable interatrial shunt system that selectively controls blood flow between the LA and RA of a patient. For example, in many embodiments disclosed herein, an adjustable interatrial device includes a shunt element that includes an outer surface configured to engage autologous tissue and an inner surface defining a lumen that allows blood to flow from the LA to the RA when the device is deployed across the septal wall. In many embodiments, the system includes an actuation assembly that can adjust the geometry of the lumen and / or the geometry of the lumen orifice to control the flow rate of blood through the lumen. In many embodiments described herein, the actuation assembly includes one or more actuation elements that are constructed from a shape memory material and are configured to undergo a material phase transition when heated above a transition temperature that is greater than body temperature. The present invention provides, for example, the following: (Item 1) A frame, a fluid passage extending through at least a portion of the frame and configured to extend between a first body region of a patient and a second body region of the patient to shunt a fluid therebetween, the fluid passage including an adjustable orifice configured to be in fluid communication with the first body region and / or the second body region; at least one shape memory actuating element configured to adjust a geometry of the adjustable orifice, the at least one shape memory actuating element being transitionable from a first material state to a second material state when heated above a transition temperature, the transition temperature being a temperature above body temperature, and transitioning the at least one shape memory actuating element from the first material state to the second material state adjusts the geometry of the adjustable orifice; and an adjustable shunt assembly including: (Item 2) 2. The adjustable shunt assembly of claim 1, wherein the at least one shape memory actuating element is a first actuating element, and the adjustable shunt further comprises a second shape memory actuating element, the second shape memory actuating element configured to adjust the geometry of the adjustable orifice, and the second shape memory actuating element is transitionable from the first material state to the second material state when heated above the transition temperature. (Item 3) 3. The adjustable shunt assembly of claim 2, wherein the first shape memory actuating element is configured to expand a cross-sectional area of ​​the adjustable orifice when heated above its transition temperature, and the second shape memory actuating element is configured to contract a cross-sectional area of ​​the adjustable orifice when heated above its transition temperature. (Item 4) 4. The adjustable shunt assembly of claim 3, wherein when the adjustable shunt assembly is implanted within a patient such that the flow path fluidly connects the first body region and the second body region, (i) increasing the cross-sectional area of ​​the adjustable orifice increases the flow rate of fluid from the first body region to the second body region, and (ii) decreasing the cross-sectional area of ​​the adjustable orifice decreases the flow rate of the fluid from the first body region to the second body region. (Item 5) 3. The adjustable shunt assembly of claim 2, wherein the first shape memory operating element has a first manufactured geometry and the second shape memory operating element has a second manufactured geometry that is different from the first manufactured geometry, and the first shape memory operating element is coupled to the second shape memory operating element such that, at body temperature, the first shape memory operating element is deformed relative to the first manufactured geometry and the second shape memory operating element is deformed relative to the second manufactured geometry. (Item 6) 6. The adjustable shunt assembly of claim 5, wherein the first shape memory actuating element is configured to move toward the first manufactured geometry when heated above the transition temperature, and the second shape memory actuating element is configured to move toward the second manufactured geometry when heated above the transition temperature. (Item 7) 3. The adjustable shunt assembly of claim 2, wherein the first shape memory actuating element is thermally isolated from the second shape memory actuating element. (Item 8) 3. The adjustable shunt assembly of claim 2, wherein the first shape memory operating element and the second shape memory operating element are thermally insulated from tissue and blood adjacent to the first shape memory operating element and the second shape memory operating element when the adjustable shunt assembly is implanted in a patient. (Item 9) 9. The adjustable shunt assembly of claim 8, wherein the first shape memory actuating element is electrically isolated from the second shape memory actuating element. (Item 10) 10. The adjustable shunt assembly of claim 9, wherein the first shape memory actuating element and the second shape memory actuating element are electrically insulated from tissue and blood adjacent to the first shape memory actuating element and the second shape memory actuating element. (Item 11) 2. The adjustable shunt assembly of item 1, further comprising a membrane, said membrane at least partially defining said flow passage and / or said orifice. (Item 12) Item 12. The adjustable shunt assembly of item 11, wherein the at least one shape memory actuation element is disposed within or otherwise coupled to the membrane and has a generally conical or cylindrical stent-like structure. (Item 13) Item 12. The adjustable shunt assembly of item 11, wherein the membrane includes a first membrane portion coupled to the frame and a second membrane portion configured to extend into the first body region or the second body region, the second membrane portion defining the adjustable orifice. (Item 14) Item 14. The adjustable shunt assembly of item 13, wherein the at least one shape memory actuation element is disposed within and / or coupled to the second membrane portion. (Item 15) 2. The adjustable shunt assembly of claim 1, wherein the at least one shape memory actuation element is radially disposed about the orifice. (Item 16) 2. The adjustable shunt assembly of claim 1, wherein the at least one shape memory working element is comprised of a Nitinol or an alloy derivative thereof, the first material state is a martensite or R-phase material state, and the second material state is an R-phase or austenitic material state. (Item 17) 2. The adjustable shunt assembly of item 1, wherein the frame is constructed from a superelastic material. (Item 18) 2. The adjustable shunt assembly of claim 1, wherein the transition temperature is greater than 40 degrees Celsius. (Item 19) 2. The adjustable shunt assembly of item 1, wherein the first body region is the left atrium of the heart and the second body region is the right atrium of the heart. (Item 20) A frame, a membrane coupled to the frame, the membrane at least partially defining a lumen, the lumen configured to extend between the first body region and the second body region to provide a fluid shunt therebetween; at least one shape memory actuating element configured to change the geometry of the lumen, the at least one shape memory actuating element being capable of transitioning from a first material state to a second material state when heated above a transition temperature, the transition temperature being a temperature above body temperature, and transitioning the at least one shape memory actuating element from the first material state to the second material state changes the geometry of the lumen; and an adjustable shunt assembly including: (Item 21) 21. The adjustable shunt assembly of claim 20, wherein the at least one shape memory operating element is a first operating element, and the adjustable shunt further comprises a second shape memory operating element, the second shape memory operating element configured to adjust the geometry of the lumen, and the second shape memory operating element is transitionable from the first material state to the second material state when heated above the transition temperature, which is greater than body temperature. (Item 22) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory operating element is configured to expand a cross-sectional area of ​​the lumen when heated above its transition temperature, and the second shape memory operating element is configured to contract a cross-sectional area of ​​the lumen when heated above its transition temperature. (Item 23) 23. The adjustable shunt assembly of claim 22, wherein when the adjustable shunt assembly is implanted within a patient such that the lumen fluidly connects the first body region and the second body region, (i) expanding the cross-sectional area of ​​the lumen increases the flow rate of fluid from the first body region to the second body region, and (ii) reducing the cross-sectional area of ​​the lumen decreases the flow rate of the fluid from the first body region to the second body region. (Item 24) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory actuating element is configured to expand the cross-sectional area along the length of the lumen and the second shape memory actuating element is configured to reduce the cross-sectional area of ​​the lumen along the length of the lumen. (Item 25) Item 25. The adjustable shunt assembly of item 24, wherein the first shape memory actuating element is configured to expand the cross-sectional area along the entire length of the lumen and the second shape memory actuating element is configured to reduce the cross-sectional area along the entire length of the lumen. (Item 26) 26. The adjustable shunt assembly of claim 25, wherein the cross-sectional area expansion is generally constant along the entire length of the lumen and the cross-sectional area reduction is generally constant along the entire length of the lumen. (Item 27) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory operating element has a first manufactured geometry and the second shape memory operating element has a second manufactured geometry that is different from the first manufactured geometry, and the first shape memory operating element is coupled to the second shape memory operating element such that, at body temperature, the first shape memory operating element is deformed relative to the first manufactured geometry and the second shape memory operating element is deformed relative to the second manufactured geometry. (Item 28) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory actuating element is configured to move toward the first manufactured geometry when heated above the transition temperature, and the second shape memory actuating element is configured to move toward the second manufactured geometry when heated above the transition temperature. (Item 29) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory element is concentrically nested within the second shape memory element. (Item 30) the first shape memory element has a first end and a second end generally opposite the first end; the second shape memory element has a third end and a fourth end generally opposite the third end; 22. The adjustable shunt assembly of claim 21, wherein the first end of the first shape memory element is coupled to the third end of the second shape memory element and the second end of the first shape memory element is spaced from the fourth end of the second shape memory element. (Item 31) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory actuating element is thermally insulated from the second shape memory actuating element. (Item 32) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory operating element and the second shape memory operating element are thermally insulated from tissue adjacent to the first shape memory operating element and the second shape memory operating element when the adjustable shunt assembly is implanted within a patient. (Item 33) 22. The adjustable shunt assembly of claim 21, wherein the first shape memory actuating element is electrically insulated from the second shape memory actuating element. (Item 34) 21. The adjustable shunt assembly of claim 20, wherein the at least one shape memory actuation element is disposed within or otherwise coupled to the membrane and has a generally conical or cylindrical stent-like structure. (Item 35) 21. The adjustable shunt assembly of claim 20, wherein the at least one shape memory working element is comprised of a derivative of Nitinol or an alloy thereof, the first material state being a martensite or R-phase material state, and the second material state being an R-phase or austenitic material state. (Item 36) 21. The adjustable shunt assembly of claim 20, wherein the frame is constructed from a superelastic material. (Item 37) 21. The adjustable shunt assembly of claim 20, wherein the transition temperature is greater than 40 degrees Celsius. (Item 38) 21. The adjustable shunt assembly of claim 20, wherein the first body region is the left atrium of the heart and the second body region is the right atrium of the heart. (Item 39) 1. An actuation assembly for varying a flow of a fluid through a conduit configured for implantation within a human patient, the actuation assembly comprising: a first shape memory element having a generally cylindrical shape and capable of transitioning between a first state and a second state when heated above a first transition temperature, the first transition temperature being a first temperature greater than body temperature; a second shape memory element having a generally cylindrical shape and capable of transitioning between a third state and a fourth state when heated above a second transition temperature, the second transition temperature being a second temperature greater than body temperature; and Including, The first shape memory element is attached to the second shape memory element. the first shape memory element is coupled to radially compress relative to a first manufactured geometry and the second shape memory element is coupled to radially expand relative to a second manufactured geometry; heating the first shape memory element above the first transition temperature, causing the first shape memory element to move toward the first fabrication geometry and the second shape memory element to deform radially outward; an actuation assembly, wherein heating the second shape memory element to a temperature greater than the second transition temperature causes the second shape memory element to move toward the second manufacturing geometry and the first shape memory element to deform radially inward. (Item 40) Item 40. The actuation assembly of item 39, wherein the first shape memory element is concentrically nested within the second shape memory element. (Item 41) the first shape memory element has a first end and a second end generally opposite the first end; the second shape memory element has a third end and a fourth end generally opposite the third end; 40. The actuation assembly of claim 39, wherein the first shape memory element is coupled to the second shape memory element such that the first end is coupled to the third end and the second end is spaced from the fourth end. (Item 42) 40. The actuation assembly of claim 39, wherein the first state and / or the third state comprises a martensitic material state. (Item 43) 40. The actuation assembly of claim 39, wherein the first state and / or the third state comprises an R-phase material state. (Item 44) 40. The actuation assembly of claim 39, wherein the second state and / or the fourth state comprises an R-phase material state. (Item 45) 40. The actuation assembly of claim 39, wherein the second state and / or the fourth state comprises an austenitic material state. (Item 46) 40. The actuation assembly of claim 39, wherein the first actuation element is thermally insulated from the second actuation element. (Item 47) Item 47. The actuation assembly of item 46, wherein the first shape memory actuating element and the second shape memory actuating element are thermally insulated from tissue and blood adjacent to the first shape memory actuating element and the second shape memory actuating element. (Item 48) 40. The actuation assembly of claim 39, wherein the first actuation element is electrically isolated from the second actuation element. (Item 49) Item 49. The actuation assembly of item 48, wherein the first shape memory actuating element and the second shape memory actuating element are electrically insulated from tissue and blood adjacent to the first shape memory actuating element and the second shape memory actuating element. (Item 50) Item 40. The actuation assembly of item 39, wherein the first temperature and the second temperature are the same. (Item 51) Item 40. The actuation assembly of item 39, wherein both the first temperature and the second temperature are greater than 40 degrees Celsius. (Item 52) 1. An adjustable shunt assembly, comprising: a frame, the frame exhibiting superelastic material properties at body temperature; a lumen extending through the frame and configured to fluidly couple and shunt fluid between a first body region and a second body region when the adjustable shunt assembly is implanted within a patient; an actuation element constructed from a shape memory material and configured to adjust the geometry of the lumen; Including, the actuating element is in a first material state at body temperature; the actuation element is configured to transition to a second material state different from the first material state and move toward a manufacturing geometry when heated above a transition temperature, the transition temperature being above body temperature; Translating the actuation element toward the manufacturing geometry adjusts the geometry of the lumen to vary the flow rate of the fluid therethrough. Adjustable shunt assembly. (Item 53) Item 53. The adjustable shunt assembly of item 52, wherein the operating element is a first operating element, the transition temperature is a first transition temperature, and the manufacturing geometry is a first manufacturing geometry, and the adjustable shunt assembly further includes a second operating element coupled to the first operating element, the second operating element having (i) a second transition temperature, the second transition temperature being a second temperature higher than body temperature, and (ii) a second manufacturing geometry different from the first manufacturing geometry. (Item 54) Item 54. The adjustable shunt assembly of item 53, wherein the first transition temperature and the second transition temperature are the same. (Item 55) Item 54. The adjustable shunt assembly of item 53, wherein the first actuating element is thermally isolated from the second actuating element. (Item 56) Item 54. The adjustable shunt assembly of item 53, wherein the first actuating element and the second actuating element are coupled together to form a composite actuator such that, at body temperature, the composite actuator assumes a third geometry that is different from the first manufactured geometry and the second manufactured geometry. (Item 57) Item 53. The adjustable shunt assembly of item 52, wherein the actuating element is constructed from a Nitinol or alloy derivative thereof. (Item 58) Item 53. The adjustable shunt assembly of item 52, wherein at least a portion of the frame is configured to receive heat in the form of energy, the received heat at least partially driving actuation of the actuation element between the first material state and the second material state. (Item 59) Item 53. The adjustable shunt assembly of item 52, wherein the first material state is a martensite or R-phase material state. (Item 60) Item 53. The adjustable shunt assembly of item 52, wherein the second material state is an R-phase or austenitic material state. (Item 61) Item 53. The adjustable shunt assembly of item 52, wherein the body element is configured to retain a generally stable geometry upon application of heat. (Item 62) 1. A method of controlling a flow of a fluid through a conduit extending between a first body region of a patient and a second body region of the patient, comprising: inducing a phase change in a first shape memory actuating element coupled to the conduit to move the first shape memory actuating element toward a first manufacturing geometry; Including, The method of claim 1, wherein a second shape memory actuating element is dragged toward the first manufacturing geometry by moving the first shape memory actuating element toward the first manufacturing geometry to change a dimension of the conduit. (Item 63) Item 63. The method of item 62, wherein inducing the phase change in the first shape memory actuating element comprises heating the first shape memory actuating element above a transition temperature, the transition temperature being a temperature greater than body temperature. (Item 64) Item 64. The method of item 63, wherein heating the first shape memory actuating element comprises resistively heating the first shape memory actuating element. (Item 65) Item 64. The method of item 63, wherein inducing the phase change comprises inducing a change in a material state of the first shape memory actuating element from a first material state to a second material state. (Item 66) Item 63. The method of item 62, wherein the first material state is a martensite or R-phase material state and the second material state is an R-phase or austenitic material state. (Item 67) Item 63. The method of item 62, wherein altering a dimension of the conduit comprises adjusting a cross-sectional area of ​​the conduit. (Item 68) Item 63. The method of item 62, further comprising inducing a phase change in the second shape memory actuating element and moving the second shape memory actuating element toward a second manufacturing geometry different from the first manufacturing geometry, wherein moving the second shape memory actuating element toward the second manufacturing geometry drags the first shape memory actuating element toward the second manufacturing geometry and adjusts the dimension of the conduit. (Item 69) 63. The method of claim 62, wherein the first body region is the left atrium of the patient's heart and the second body region is the right atrium of the patient's heart. (Item 70) 1. A method of controlling a flow of a fluid through a shunt having a first shape memory actuating element coupled to a second shape memory actuating element, comprising: adjusting the geometry of a lumen and / or a lumen orifice fluidly connecting the first body region to the second body region; Including, Adjusting the geometry of the lumen and / or the lumen orifice may include activating a first shape memory actuating element to expand a size of the lumen and / or the lumen orifice and increase a flow rate of the fluid through the lumen, whereby actuating the first shape memory actuating element causes the first shape memory actuating element and the second shape memory actuating element to radially expand; and / or activating a second shape memory actuating element to reduce a size of the lumen and / or the lumen orifice and decrease a flow rate of the fluid through the lumen, wherein actuating the second shape memory actuating element causes the second shape memory actuating element and the first shape memory actuating element to radially compress; A method comprising: (Item 71) Item 71. The method of item 70, wherein the first shape memory actuating element is concentrically nested within the second shape memory actuating element. (Item 72) activating the first shape memory actuating element includes heating the first shape memory actuating element above a first transition temperature, the first transition temperature being a first temperature greater than body temperature; Item 71. The method of item 70, wherein actuating the second shape memory actuating element comprises heating the second shape memory actuating element above a second transition temperature, the second transition temperature being a second temperature above body temperature. (Item 73) 73. The method of claim 72, wherein the first transition temperature is the same as the second transition temperature. (Item 74) activating the first shape memory actuating element includes transitioning the first shape memory actuating element from a first material state to a second material state; Item 71. The method of item 70, wherein actuating the second shape memory actuating element comprises transitioning the second shape memory actuating element from a third material state to a fourth material state. (Item 75) 1. A method of forming an actuator assembly for selectively controlling a flow of a fluid through a conduit configured to be implanted within a human patient, comprising: providing a first shape memory actuating element having a first manufactured geometry; providing a second shape memory actuating element having a second manufactured geometry different from the first manufactured geometry; coupling the first shape memory actuating element to the second shape memory actuating element such that the first shape memory actuating element radially compresses relative to the first manufactured geometry and the second shape memory actuating element radially expands relative to the second manufactured geometry; A method comprising: (Item 76) Item 76. The method of item 75, wherein coupling the first shape memory actuating element to the second shape memory actuating element comprises nesting the first shape memory actuating element within the second shape memory actuating element. (Item 77) Item 76. The method of item 75, wherein coupling the first shape memory operating element to the second shape memory operating element comprises coupling a first end of the first shape memory operating element to a second end of the second shape memory operating element such that the first shape memory operating element and the second shape memory operating element do not substantially overlap. (Item 78) Item 76. The method of item 75, wherein providing the first shape memory actuating element comprises cutting the first shape memory actuating element from a sheet of Nitinol or an alloy thereof, and providing the second shape memory actuating element comprises cutting the second shape memory actuating element from a sheet of Nitinol or an alloy thereof. (Item 79) 76. The method of claim 75, wherein coupling the first shape memory operating element to the second shape memory operating element is performed when the first shape memory operating element and / or the second shape memory operating element are in a martensite and / or R-phase material state. (Item 80) a frame including a scaffold formed from a shape memory material, the scaffold including a first end and a second end; a membrane around a portion of the scaffold and at least partially defining a fluid lumen positioned between the first end and the second end; Including, The adjustable shunt, wherein the scaffold is configured to change between a first geometry and a second geometry when subjected to a shape memory change by application of heat. (Item 81) Item 81. The shunt of item 80, wherein the lumen is defined by an inlet orifice, the first geometry having an orifice with a larger diameter than the second geometry. (Item 82) Item 81. The shunt of item 80, wherein the lumen is defined by an inlet orifice, the first geometry having an orifice with a smaller diameter than the second geometry. (Item 83) Item 81. The shunt of item 80, wherein the lumen is defined by an outlet orifice, the first geometry having an orifice with a larger diameter than the second geometry. (Item 84) Item 81. The shunt of item 80, wherein the lumen is defined by an outlet orifice, the first geometry having an orifice with a smaller diameter than the second geometry. (Item 85) Item 81. The shunt of item 80, wherein a cross-section of the lumen is different in the first geometry as compared to the second geometry. (Item 86) Item 81. The shunt of item 80, wherein the lumen has a generally cylindrical section, the diameter of the cylindrical section being different in the first geometry as compared to the second geometry. (Item 87) Item 81. The shunt of item 80, wherein the frame is formed entirely from the scaffold. (Item 88) Item 81. The shunt of item 80, wherein the scaffold is configured to change to the second geometry at a transition temperature above a patient's body temperature. (Item 89) Item 81. The shunt of item 80, wherein the scaffold is configured to change to the second geometry at a temperature greater than 40 degrees Celsius. (Item 90) Item 81. The shunt of item 80, wherein the frame further comprises an anchor for fixing within a target location in the patient. (Item 91) Item 81. The shunt of item 80, wherein the frame is expandable. (Item 92) Item 81. The shunt of item 80, wherein when the frame is in the expanded configuration, the width of the fluid lumen is less than 150 microns. (Item 93) Item 81. The shunt of item 80, wherein the width of the fluid lumen is less than 30 Fr (10 mm) when the frame is in the expanded configuration. (Item 94) 1. A method for adjusting an implantable shunt, comprising: non-invasively transmitting a signal to an implanted shunt, the shunt including a shape memory scaffold having a portion defining a fluid lumen; changing the fluid lumen from a first geometry to a second geometry by heating the shape memory scaffold in response to the signal; A method comprising: (Item 95) 95. The method of claim 94, wherein the heating comprises heating an inlet of the fluid lumen to change the inlet from a first geometry to a second geometry. (Item 96) Item 95. The method of item 94, wherein the heating comprises heating an outlet of the fluid lumen to change the outlet from a first geometry to a second geometry. (Item 97) Item 95. The method of item 94, wherein the heating is resistive heating. (Item 98) 95. The method of claim 94, wherein the signal is one of an RF or a magnetic signal. (Item 99) receiving said signal; converting said signal into electrical energy; 99. The method of claim 98, further comprising: (Item 100) 1. A method of adjusting an implantable shunt for treating heart failure, comprising: evaluating a shunt for providing therapy to a patient, the shunt having a fluid lumen facilitating fluid flow between a left side and a right side of the patient's heart; determining an adjustment to a flow resistance provided through the fluid lumen based on said evaluating; and conditioning the shunt by exerting a radially inward force on the shunt to reduce a cross-sectional area of ​​at least a portion of a fluid lumen of the shunt; A method comprising: (Item 101) Item 101. The method of item 100, wherein adjusting the shunt comprises adjusting a cross-section of an outflow end of the fluid lumen. (Item 102) Item 101. The method of item 100, wherein adjusting the shunt comprises adjusting a cross-section of an inflow end of the fluid lumen. (Item 103) Item 101. The method of item 100, wherein the fluid lumen includes an inflow end, an outflow end, and a body between the inflow end and the outflow end, and adjusting the shunt includes adjusting a cross-section of a portion of the body. (Item 104) Item 101. The method of item 100, wherein the shunt comprises a shape memory element, and conditioning the shunt comprises delivering energy to the shape memory element to induce a change in a material state of the shape memory element, further wherein the change in material state imparts the radially inward force on the shunt. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an interatrial device implanted in the heart and configured in accordance with an embodiment of the present technology; [Figure 2A] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 2B] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 2C] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 2D] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 2E] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 2F] 1 is a series of schematic diagrams illustrating an adjustable inter-atrial shunt assembly constructed in accordance with selected embodiments of the present technology. [Figure 3A] 1 is a schematic diagram of coupled working element members forming part of an inter-atrial shunt assembly, constructed in accordance with selected embodiments of the present technology; [Figure 3B] 1 is a schematic diagram of coupled working element members forming part of an inter-atrial shunt assembly, constructed in accordance with selected embodiments of the present technology; [Figure 4] 1A-C are schematic diagrams of an inter-atrial shunt system including a nested working element and configured in accordance with selected embodiments of the present technology. [Figure 5A] 1 is a schematic diagram of combined working elements for use with an adjustable inter-atrial shunt system and configured in accordance with selected embodiments of the present technology. [Figure 5B]1 is a schematic diagram of combined working elements for use with an adjustable inter-atrial shunt system and configured in accordance with selected embodiments of the present technology. [Figure 6] 5C is a series of schematic diagrams illustrating the operation of the shunt system shown in FIGS. 5A and 5B. FIG. [Figure 7] 1 is a schematic diagram of combined working elements for use with an adjustable inter-atrial shunt system and configured in accordance with selected embodiments of the present technology. [Figure 8A] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 8B] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 8C] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 8D] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 8E] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 8F] 1 is a schematic diagram of an adjustable inter-atrial shunt system including an elongated working element and configured in accordance with selected embodiments of the present technology. [Figure 9] 1 is a schematic diagram of an adjustable inter-atrial shunt system including a helical shaped working element and configured in accordance with selected embodiments of the present technology. [Figure 10] 1A and 1B are schematic diagrams of another adjustable inter-atrial shunt system including a helical shaped working element and configured in accordance with selected embodiments of the present technology. [Figure 11] FIG. 1 is a schematic diagram of an adjustable inter-atrial shunt system including multiple individual working elements and configured in accordance with selected embodiments of the present technology. [Figure 12] 1A and 1B are schematic diagrams of serially coupled operative elements forming part of an inter-atrial shunt system constructed in accordance with selected embodiments of the present technology. [Figure 13] 1A-D show various embodiments of working elements positioned within an inter-atrial shunt system constructed in accordance with an embodiment of the present technology. [Figure 14] 1A-C show an adjustable inter-atrial shunt system in a first configuration and configured in accordance with selected embodiments of the present technology. [Figure 15] 14A-14C show the adjustable inter-atrial shunt system shown in FIGS. 14A-14C in a second configuration different from the first configuration. [Figure 16A] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 16B] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 16C] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 16D] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 17A] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 17B] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 17C] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 18A] 17A-17C illustrate the operation of the adjustable inter-atrial shunt system. [Figure 18B] 17A-17C illustrate the operation of the adjustable inter-atrial shunt system. [Figure 18C]17A-17C illustrate the operation of the adjustable inter-atrial shunt system. [Figure 19A] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 19B] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 19C] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 19D] 1 illustrates another adjustable inter-atrial shunt system, constructed in accordance with selected embodiments of the present technology. [Figure 20] 1A-C show another adjustable inter-atrial shunt system constructed in accordance with selected embodiments of the present technology. [Figure 21A] 1 illustrates an adjustable inter-atrial shunt system with a mechanical adjustment mechanism and configured in accordance with selected embodiments of the present technology. [Figure 21B] 1 illustrates an adjustable inter-atrial shunt system with a mechanical adjustment mechanism and configured in accordance with selected embodiments of the present technology. [Figure 21C] 1 illustrates an adjustable inter-atrial shunt system with a mechanical adjustment mechanism and configured in accordance with selected embodiments of the present technology. [Figure 21D] 1 illustrates an adjustable inter-atrial shunt system with a mechanical adjustment mechanism and configured in accordance with selected embodiments of the present technology. [Figure 22] 21A-21C show the adjustable interatrial shunt system of FIGS. 21A-21D implanted across the septal wall. [Diagram 23] 21A-C illustrate operations for invasively deploying the adjustable inter-atrial shunt system of FIGS. 21A-21D. [Figure 24] FIG. 1 is a partial isometric view of an adjustable inter-atrial shunt system including radially arranged working elements and configured in accordance with selected embodiments of the present technology. [Figure 25A]25 illustrates additional features of the radially disposed working elements of the adjustable interatrial shunt system of FIG. 24. [Figure 25B] 25 illustrates additional features of the radially disposed working elements of the adjustable interatrial shunt system of FIG. 24. [Figure 25C] 25 illustrates additional features of the radially disposed working elements of the adjustable interatrial shunt system of FIG. 24. [Figure 25D] 25 illustrates additional features of the radially disposed working elements of the adjustable interatrial shunt system of FIG. 24. [Figure 26] FIG. 13 is a partial isometric view of another adjustable inter-atrial shunt system including radially disposed working elements and configured in accordance with selected embodiments of the present technology. [Figure 27] FIG. 13 is a partial isometric view of another adjustable inter-atrial shunt system including radially disposed working elements and configured in accordance with selected embodiments of the present technology. [Figure 28A] FIG. 1 is a partial isometric view of an adjustable inter-atrial shunt system including a stent-like working element and configured in accordance with selected embodiments of the present technology. [Figure 28B] FIG. 1 is a partial isometric view of an adjustable inter-atrial shunt system including a stent-like working element and configured in accordance with selected embodiments of the present technology. [Figure 28C] FIG. 1 is a partial isometric view of an adjustable inter-atrial shunt system including a stent-like working element and configured in accordance with selected embodiments of the present technology. [Figure 28D] FIG. 1 is a partial isometric view of an adjustable inter-atrial shunt system including a stent-like working element and configured in accordance with selected embodiments of the present technology. [Figure 28E] FIG. 28B is a partial schematic diagram of a stent-like working element of the adjustable inter-atrial shunt system of FIGS. 28A-28D. [Figure 28F] FIG. 28B is a partial schematic diagram of a stent-like working element of the adjustable inter-atrial shunt system of FIGS. 28A-28D. [Figure 28G] FIG. 28B is a partial schematic diagram of a stent-like working element of the adjustable inter-atrial shunt system of FIGS. 28A-28D. [Fig. 28H] FIG. 28B is a partial schematic diagram of a stent-like working element of the adjustable inter-atrial shunt system of FIGS. 28A-28D. [Figure 29] 11A-D show an adjustable interatrial system constructed in accordance with a further embodiment of the present technology. [Figure 30A] 1 illustrates an adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 30B] 1 illustrates an adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 30C] 1 illustrates an adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 30D] 1 illustrates an adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 30E] 1 illustrates an adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 31A] 1 illustrates another adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Figure 31B] 1 illustrates another adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Diagram 32] 1 illustrates yet another adjustable inter-atrial shunt system including a linear actuation mechanism and configured in accordance with selected embodiments of the present technology. [Diagram 33] 1 is a graph illustrating the relationship between aperture diameter and translational motion of a linear actuation mechanism in an inter-atrial shunt system configured in accordance with an embodiment of the present technology; [Diagram 34]1A-D are schematic illustrations of various anchor scaffolds for use with an adjustable inter-atrial shunt system configured in accordance with selected embodiments of the present technology. [Diagram 35] 1A and 1B are schematic diagrams of an adjustable inter-atrial shunt system having both superelastic and shape memory properties and constructed in accordance with selected embodiments of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The terms used in the description presented below are intended to be interpreted in the broadest reasonable manner, although they are used in conjunction with the detailed description of certain specific embodiments of the present technology. Certain terms may be emphasized below. However, any terms intended to be interpreted in a limiting manner are expressly and specifically defined as such in this "Description of the Preferred Embodiments" section. Furthermore, the present technology may include other embodiments that are within the scope of the claims but are not described in detail with respect to Figures 1-35B. In various respects, the terms used to describe shape memory behavior may adopt the conventions set forth in ASTM F2005 (Standard Terminology for Nickel-Titanium Shape Memory Alloys).

[0010] Throughout this specification, reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the technology. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, particular features or characteristics may be combined in any suitable manner in one or more embodiments.

[0011] Throughout this specification, references to relative terms such as, for example, "about" and "approximately" are used herein to mean plus or minus 10% of the stated value.

[0012] As used herein, in various embodiments, the terms "interatrial device", "interatrial shunt device", "IAD", "IASD", "interatrial shunt", and "shunt" are used interchangeably and refer, in at least one configuration, to a shunt element that provides blood flow between a first region (e.g., the LA of the heart) and a second region (e.g., the RA or coronary sinus of the heart) of a patient. Although described in terms of a shunt between the atrium, i.e., the LA and the RA, it will be understood that the present technology can be applied to other medical devices as well. For example, a shunt may be positioned between other chambers and channels of the heart, or other parts of the cardiovascular system. For example, any of the shunts described herein, including those referred to as "interatrial", may nevertheless be used and / or modified to shunt between the LA and the coronary sinus, or between the right pulmonary vein and the superior vena cava. Additionally, while the disclosure herein primarily describes shunting of blood from the LA to the RA, the present technology can be readily adapted to shunt blood from the RA to the LA to treat certain conditions, such as pulmonary hypertension. For example, a particular patient may have blood shunted from RA to LA using a mirror image, or possibly the same embodiment, of the embodiment used to shunt blood from LA to RA. In another example, a shunt may be used to facilitate flow between organs, between organs and blood vessels, etc. Shunts may also be used for fluids other than blood. The technology described herein may be used for ophthalmic shunts to flow aqueous solutions or fluids to treat gastrointestinal disorders. The technology described herein may be used to control the delivery of other fluids, such as saline, drugs, or medications.

[0013] As used herein, the term "geometry" can include the size and / or shape of an element. Thus, when the present disclosure describes a change in geometry, it can refer to a change in the size of an element (e.g., moving from a small circle to a large circle), a change in the shape of an element (e.g., moving from a circle to an ellipse), and / or a change in the shape and size of an element (e.g., moving from a small circle to a large ellipse). In various embodiments, "geometry" refers to the relative placement and / or position of elements in a respective system.

[0014] As used herein, the term "manufactured geometry" can refer to a preferred geometric configuration of a shape memory component. For example, a shape memory component generally assumes a manufactured geometry in the absence of mechanical stress or other deformation. A manufactured geometry can include an "as cut" geometry, a temperature set geometry, a shape set geometry, etc.

[0015] The headings provided herein are for convenience only and do not interpret the scope or meaning of the technology claimed herein.

[0016] A. Interatrial shunts for the treatment of heart failure Heart failure can be classified into one of at least two categories based on the ejection fraction experienced by the patient: (1) HFpEF, historically referred to as diastolic heart failure, or (2) HFrEF, historically referred to as systolic heart failure. One definition of HFrEF is a left ventricular ejection fraction lower than 35%-40%. The underlying pathophysiology and treatment regimens for each classification of heart failure, although related, can be quite different. For example, there are established pharmacologic therapies that can treat the symptoms of HFrEF and sometimes be useful in slowing or reversing disease progression, but pharmacologic therapies available for HFpEF are limited and of only questionable efficacy.

[0017] In patients with heart failure, abnormal functioning in the left ventricle (LV) leads to increased pressure in the LA. This directly translates to higher pressure in the pulmonary venous system, which is then fed into the LA. As pulmonary venous pressure increases, fluid is forced out of the capillaries and into the lungs. This fluid accumulation causes many of the symptoms of heart failure, including pulmonary congestion and signs of shortness of breath and exertion even with light physical activity. Risk factors for HF include renal impairment, hypertension, hyperlipidemia, diabetes, smoking, obesity, older age, and obstructive sleep apnea. HF patients may have increased LV stiffness, which can lead to reduced LV relaxation during diastole, resulting in increased pressure and insufficient ventricular filling. HF patients may also be at higher risk for atrial fibrillation and pulmonary hypertension, and usually have other comorbidities that may complicate treatment options.

[0018] Interatrial shunts have recently been proposed as a way to reduce elevated left atrial pressure, and this new class of cardiovascular therapeutic intervention has demonstrated significant clinical promise. For example, FIG. 1 shows a conventional shunt placement in the septal wall between the LA and RA. Most conventional interatrial shunts (e.g., shunt 10) involve creating a fluid communication path between the LA and RA by creating a hole or by inserting an implant with a lumen into the atrial septal wall. Thus, elevated left atrial pressure may be partially alleviated by unloading the LA to the RA. Early clinical trials have shown that this approach improves symptoms of heart failure.

[0019] One of the challenges with many conventional interatrial shunts is determining the most appropriate size and shape of the shunt lumen. If the lumen is too small, the LA may not be properly unloaded and symptoms may not be relieved. If the lumen is too large, the RA and right heart may be generally overloaded, creating new problems for the patient. Furthermore, due in part to an incomplete understanding of the pathophysiology of HFpEF (and to a lesser extent HFrEF), the association between pressure reduction and clinical outcome, and the degree of pressure reduction required for optimized outcomes, are not yet fully understood. As such, clinicians are forced to make their best guess when selecting an appropriately sized shunt (based on limited clinical evidence) and typically cannot adjust the size over time. To make matters worse, clinicians must select shunt size and / or available device design based on general factors (e.g., size of patient anatomy, hemodynamic measurements of the patient taken in one snapshot at a time, etc.) rather than on the health and predicted response of the individual patient. With conventional devices, clinicians do not have the ability to adjust or dose therapy once the device is implanted in response to changes in the patient's condition, such as disease progression. In contrast, an inter-atrial shunt system configured in accordance with embodiments of the present technology allows the clinician to select size peri-operatively or post-implant based on the patient.

[0020] B. Shape Memory Actuation Assembly As mentioned above, the present technology is generally directed to inter-atrial shunt systems. Such systems include a shunt element implantable in a patient at or adjacent to the septal wall. In some embodiments, the shunt element includes a frame configured to interface with the septal wall, and a membrane coupled to the frame to define a lumen. The shunt element (e.g., the lumen) can fluidly connect the LA and RA of the patient to facilitate blood flow therebetween. In some embodiments, the shunt element includes and / or is operably coupled to an actuating assembly, which is invasively and / or non-invasively adjustable to selectively control blood flow between the LA and RA. In some embodiments, the system can further include, among others, an energy receiving component, an energy storing component, and / or one or more sensors.

[0021] In some embodiments, the interatrial shunt system includes an actuating assembly having one or more actuating elements. As described in detail below, the actuating elements are configured to change the geometry or other characteristics of the lumen extending through the shunt element to alter the flow rate of fluid through the lumen. For example, in some embodiments, the actuating elements can selectively change the size and / or shape of the lumen to alter the flow rate of fluid through the lumen. In particular, the actuating elements can be configured to selectively enlarge the diameter of the lumen (or a portion of the lumen) and / or selectively reduce the diameter of the lumen (or a portion of the lumen) in response to an input. Throughout this disclosure, references to adjusting a diameter (e.g., enlarging a diameter, reducing a diameter, etc.) can refer to adjusting the hydraulic or equivalent diameter of the lumen, adjusting the diameter at a particular location of the lumen, and / or adjusting the diameter along the length (e.g., the entire length) of the lumen. In other embodiments, the actuating elements are configured to affect the shape or geometry of the lumen in other ways. In some embodiments, the actuating element is configured to adjust the geometry (e.g., cross-sectional area, diameter, size) of an orifice or aperture of the lumen (e.g., an inflow or outflow orifice positioned in or adjacent to the LA or RA, respectively). For example, the actuating element can be configured to selectively enlarge the cross-sectional area of ​​the outflow orifice in the RA and / or selectively reduce the cross-sectional area of ​​the outflow orifice in the RA in response to an input. In some embodiments, the actuating element can selectively change the geometry of both the lumen and the lumen orifice.

[0022] Thus, the actuating element can be coupled to and / or included within the shunt element to drive a geometric change in the lumen and / or orifice. In some embodiments, the actuating element is part of the shunt element and at least partially defines the lumen. For example, the actuating element can be disposed within or otherwise coupled to a membrane that at least partially defines the lumen of the shunt element. In other embodiments, the actuating element is spaced apart from the shunt element but operably coupled thereto.

[0023] In some embodiments, at least a portion of the actuating element can include a shape memory element. The shape memory portion can include a shape memory metal or alloy, such as Nitinol, a shape memory polymer, a pH-based shape memory material, or any other suitable material configured to move or otherwise adjust in response to an input. For example, the actuating element can include one or more Nitinol elements configured to change shape in response to the application of heat that raises the temperature of the Nitinol element above a transformation temperature of the material. In such embodiments, the actuating element can be selectively actuated by the application of energy to heat the Nitinol element(s). In some embodiments, the shape memory material can extend around at least a portion of the lumen. In some embodiments, the shape memory material can extend around at least a portion of the lumen orifice. In some embodiments, the shape memory material can be separate from but operably coupled to the lumen and / or lumen orifice.

[0024] Movement of the actuating element can be caused by an externally applied input and / or by use of a shape memory effect (e.g., driven by a change in temperature). The shape memory effect allows a deformation that has altered the element from its original or preferred shaped geometric configuration (also referred to herein as the "manufactured geometry" or "temperature-set geometry") to be largely or entirely reversed during operation of the actuating element. For example, sufficient heating can cause a change in material state (e.g., a phase change) in the actuator material, inducing a temporarily elevated internal stress that drives the shape change toward the original shaped geometric configuration, thereby reversing the deformation. In the case of a shape memory alloy, the change in state can be from a martensite phase (alternatively, R-phase) at low temperature to an austenite phase (alternatively, R-phase) at high temperature. In the case of a shape memory polymer, the change in state can be due to a glass transition or melting temperature. The change in material state allows the material's deformation(s) (e.g., relative to its manufactured geometry) to be restored without any external stress being applied to the actuator element. That is, the deformation present in the material at a first temperature (e.g., body temperature) can be restored and / or altered by raising the material to a second (e.g., higher) temperature. Upon cooling (and re-changing state, e.g., back to the martensitic phase), the actuator element can retain approximately its manufactured geometry. However, because the material is in this relatively cool state, the force or stress required to thermoelastically deform the material can be lower, and any subsequent application of external stress can cause the actuator element to re-deform away from the manufactured geometry.

[0025] The shape memory alloy actuating element can be processed such that the transition temperature (e.g., austenite start temperature, austenite finish temperature, etc.) at which a change in state occurs is higher than a threshold temperature (e.g., body temperature). For example, the transition temperature can be set to about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, or another higher or lower temperature. In some embodiments, as a result of heating the actuator material from body temperature to a temperature higher than the austenite start temperature (or alternatively, a temperature higher than the R-phase start temperature), the upper plateau stress (e.g., "UPS_body temperature") of the material in the first state (e.g., the thermoelastic martensite phase or the thermoelastic R-phase at body temperature) becomes lower than the upper plateau stress (e.g., "UPS_operating temperature") of the material in the heated state (e.g., the superelastic state), whereby partial or complete free recovery is achieved. For example, the actuator material can be heated such that UPS_operating temperature > UPS_body temperature. In some embodiments, as a result of heating the actuator material from body temperature to a temperature higher than the austenite start temperature (or alternatively, a temperature higher than the R-phase start temperature), the upper plateau stress of the material in the first state (e.g., the thermoelastic martensite or the thermoelastic R-phase) becomes lower than the lower plateau stress (e.g., "LPS") of the material in the heated state, whereby partial or complete free recovery is achieved. For example, the actuator material can be constructed such that LPS_activation temperature > UPS_body temperature. In some embodiments, as a result of heating the actuator material from body temperature to a temperature higher than the austenite start temperature (or alternatively, a temperature higher than the R-phase start temperature), the upper plateau stress of the material in the first state (e.g., the thermoelastic martensite or the thermoelastic R-phase) becomes higher than the lower plateau stress of the material in the heated state, whereby partial free recovery is achieved. For example, the actuator material can be constructed such that LPS_activation temperature < UPS_body temperature.

[0026] In some embodiments, the actuating assembly is formed by combining at least two actuating elements (e.g., having different manufacturing geometries) to form a composite actuating element (which may also be referred to as an "actuating assembly"). In some embodiments, at least one of the elements that comprise the composite actuating element is a shape memory element. In some embodiments, both elements that comprise the composite actuating element are shape memory elements. In some embodiments, the combining is performed with at least one actuating element in a thermoelastically deformable (e.g., thermoelastic martensite or thermoelastic R-phase) state at implantation temperature. In some embodiments, the combining is performed with at least one actuating element(s) in a superelastic state. In some embodiments, the flow control element comprises an expanding or contracting element, the deformation of which can be achieved by applying a force (e.g., balloon expansion) at a lower temperature (e.g., body temperature) and / or by applying heat (e.g., electrical resistance heating) at a higher temperature (e.g., a temperature above the austenite start or R-phase start temperature). In some embodiments, the shape memory component is constructed in a manner that includes a geometry (e.g., cross-sectional area, diameter, length, radius of curvature, or circumference). In some embodiments, at least two actuation elements have a geometric configuration (e.g., diameter) D A0 and D. B0 (D A0 >D B0 In some embodiments, the actuation assemblies are arranged in substantially the same geometric configuration (e.g., D A0 =D B0 The flow control element is formed from at least two actuating elements constructed with a casing such that prior to introduction (i.e., implantation) into a patient or upon introduction into a patient, at least one of the two or more coupled actuating elements is deformed relative to their original geometric configuration (e.g., D A1 ≠D A0 , and / or D. B1 ≠D B0 In some embodiments, the geometry (e.g., diameter) of the first actuation element can be reduced (e.g., compressed) relative to its original configuration (e.g., DA1 <D A0 ) and the geometry (e.g., diameter) of the second actuating element increases (e.g., expands) relative to its original configuration (e.g., D B1 >D B0 ), the at least two coupled actuating elements can be deformed prior to or during implantation. With the shape memory components in a first (e.g., martensitic) material state, thermoelastic deformation of the actuating elements to a desired configuration can occur. At a given temperature (e.g., at equilibrium), the coupled and deformed actuating elements can form a composite geometry (e.g., cross-sectional area) having dimensions different from either of the shaped configurations of the first and second actuating elements. For example, the composite geometry (e.g., diameter, D) of the flow control element can be determined by the shape memory components in a first (e.g., martensitic) material state. C0 ) can be between the configured configurations of the first and second actuation elements (e.g., D A0 >D C0 >D B0 ).

[0027] The actuation assembly may be configured such that its composite geometry and / or dimensions change (e.g., D C1 ≠D C0The flow control element can cause a change in the overall dimension of the flow passage (e.g., lumen). For example, the overall dimension can include an overall cross-sectional area, diameter, length, circumference, or another attribute. In one embodiment, the first and second actuating elements are arranged to be joined to form a composite element such that a movement of the first actuating element (e.g., achieving free recovery via a thermoelastic martensitic transformation) is accompanied (e.g., causes) by a complementary full or partial movement of the second actuating element, such as inducing a thermoelastically recoverable deformation of a relatively malleable second actuating element while the second actuating element is at least partially in a thermoelastic martensite (or thermoelastic R-phase) material state. (For brevity herein, in various embodiments, the term "relatively malleable" is used to describe a material state in which a component requires a lower force or stress to deform it when compared to another component or compared to the same component in a different material state). The movement(s) can include a compression (e.g., contraction) or expansion (e.g., opening) of the composite element. The movement can have a deflection or deformation that can be fully or partially recoverable. The complementary movement of the second actuating element can include (a) movement along the same axis, (b) movement about the same axis, or (c) movement along the same dimension (e.g., radial) as the primary movement of the first actuating element, or another movement. In some embodiments, actuation of the first actuating element from a compressed geometry toward a geometry of a larger shaped configuration expands a composite geometry due to coupling of the first actuating element with the second actuating element. In some embodiments, this expansion places the composite geometry at a size larger than its equilibrium state but smaller than the size of the original configuration of the first actuating element (e.g., D A0 >D C1 >D C0). In some embodiments, actuation of the second actuating element from an expanded geometry toward a smaller original configuration geometry contracts (e.g., compresses) the composite geometry due to coupling of the second actuating element with the first actuating element. In some embodiments, this compression places the composite geometry at a size smaller than its equilibrium state but larger than the size of the second actuating element's original configuration (e.g., D C0 >D C1 >D B0 ).

[0028] In a method of operation of one embodiment of the present technology, selective heating of a first actuating element of a flow control element causes the first actuating element to move toward its original geometric configuration (e.g., D A1 From D A0 The actuation can be caused by increasing the temperature of the first actuating element to at least a threshold transition temperature. The transition temperature can be a phase transition temperature (e.g., an R-phase start temperature, an austenite start temperature, an R-phase finish temperature, or an austenite finish temperature). An increase in temperature above the transition temperature can induce a material to change from a first phase (e.g., martensite or R-phase) to a second phase (e.g., R-phase or austenite). During actuation of the first actuating element, the second actuating element remains in a first (e.g., martensite or R-phase) material state because it is generally not heated (e.g., remains at or near body temperature). As such, the second actuating element can be relatively malleable in this material state such that an increased force due to partial or full free recovery of the first actuating element can drive a change in the shape and / or geometry of the coupled second element (e.g., a compressive or contractive movement). Due to the relatively malleable nature of the second actuating element in this material state, the second actuating element is able to largely retain this induced shape and / or geometry change without substantial recovery (e.g., with only generally linear elastic recovery).

[0029] Following completion of the heating period of the first actuating element, the first actuating element is cooled and transformed into a relatively malleable low temperature phase (e.g., martensite or R-phase). To reverse the induced change in the configuration (e.g., its geometry) of the composite flow control element, the second actuating element is heated above its transformation temperature to induce a phase change (e.g., R-phase or austenite) and thereby transform the geometry toward its original geometric configuration (e.g., D B1 From D B0 During this time, the flow control element can undergo a partial or complete free recovery (e.g., shrink in size) as the second actuating element returns to its original geometric configuration because the first actuating element is not selectively heated and is relatively non-malleable. In some embodiments, the geometry of the flow control element can be toggled repeatedly (e.g., between expansion and contraction) by repeating the aforementioned operations. Heating of the actuating element can be achieved by applying incident energy (e.g., by laser, resistive heating, or inductive coupling). The source of incident energy can be either internal to the patient (e.g., delivered by a catheter) or external (e.g., RF energy delivered non-invasively).

[0030] In some embodiments, the first actuating element can be thermally and / or electrically isolated from the second actuating element. Further, in some embodiments, the first and second actuating elements can be thermally and / or electrically isolated from tissue and blood adjacent to the implantation site.

[0031] Thus, the present technology provides an actuation assembly including two or more shape memory material actuation elements, which are fabricated in different geometric configurations and bonded together. In additional embodiments, the geometric configurations may be similar because the two or more actuation elements function in an antagonistic or complementary manner to manipulate the geometric features of the actuation assembly. In some embodiments, the actuation elements may be fabricated with similar chemical compositions and / or thermomechanical post-treatments, i.e., they may have similar phase transition temperature profiles. In further embodiments, the actuation assembly may include two or more actuation elements, which are fabricated with different chemical compositions and / or thermomechanical post-treatments, such that they do not share the same phase transition temperature profile. In operation of such embodiments, energy may be provided to the entire composite actuation assembly (e.g., comprised of two or more individual actuation elements), and all the individual actuation elements may not deform similarly toward their original geometric configurations. For example, a first actuation element may have a first transition temperature profile, and a second actuation element may have a higher second transition temperature profile. Heating the composite actuating assembly to a temperature above the first transition temperature but below the second transition temperature (e.g., an R-phase start, austenite start, R-phase finish, or austenite finish temperature) induces more substantial thermoelastic recovery in the first actuating element than in the second actuating element, which results in a change in the first geometry of the actuating assembly. Heating the composite actuating assembly to a temperature above both the first and second transition temperatures (e.g., an R-phase start, austenite start, R-phase finish, or austenite finish temperature) can induce significant thermoelastic recovery and actuation in both actuating elements, which results in a change in the second geometry of the actuating assembly, which may be different from the change in the first geometry.

[0032] In embodiments, the change in geometry of the actuation assembly can be toggled between several states in response to actuation of one or more actuation elements. In embodiments, reversal of the change in geometry (e.g., making the lumen larger after it had previously been made smaller) is accomplished by utilizing multiple shape-memory actuation elements coupled to function in an antagonistic manner. In embodiments, other mechanisms (e.g., springs, ratchets, elastic materials such as silicone, etc.) may additionally or alternatively be utilized in combination with the actuation elements to affect the change in geometry of the actuation assembly by providing complementary or counterforces to the actuation elements.

[0033] In an embodiment, the actuating assembly can expand thermoelastically to a cross-sectional geometry larger than the largest actuating element in the composite structure. For example, one actuating element may have an initial diameter D A0 and the other actuating element may have an initial diameter D B0 (e.g., D A0 >D B0 In such a composite system, actuation of any one of the actuating elements causes the composite actuating assembly to B0 ~D A0 For example, if a physician drives the actuation assembly to a diameter within the range of D A0 When tool crossing is permitted (e.g., during transcatheter deployment of the mitral valve) by inflating (e.g., using a balloon) to a larger diameter, the lumen of the actuating assembly may be expanded to allow subsequent actuation of any of the actuating elements (e.g., by application of heat) to restore the diameter of the actuating assembly to its original range D. B0 ~D A0 In various embodiments, the actuation assembly can be thermoelastically recovered by driving it to D A0 Expanding to a larger diameter allows for the crossing of a catheter, e.g., a diagnostic catheter or a therapeutic catheter. In an embodiment, the plastic deformation of either (or both) working elements is A0 This can be attributed to the expansion into a larger lumen. As a result, the achievable operable lumen range is D B1 ~DA1 (Here, taking into account permanent plastic deformation, D B1 >D B0 and D. A1 >D A0 ).

[0034] C. Shunt Assembly with Adjustable Flow Lumen The present technology provides an inter-atrial shunt assembly with an adjustable flow lumen. For example, Figures 2A-2F show an adjustable inter-atrial shunt system 200 ("system 200") configured in accordance with selected embodiments of the present technology. As one of ordinary skill in the art will appreciate, Figures 2A-2F are provided solely to demonstrate the adjustable nature of the shunt systems described herein. Additional details of the various components of the present technology are described in more detail with reference to specific embodiments of Figures 3A-35B.

[0035] 2A, system 200 includes a frame 210 and an anchor 230 extending from frame 210. System 200 further includes a shunt element 215 comprised of a membrane 220 defining a lumen 225 extending therethrough. As discussed below, when shunt system 200 is implanted across a septal wall S in a patient's heart, lumen 225 is configured to fluidly connect LA and RA and shunt blood therebetween. In FIG. 2A, lumen 225 has a first diameter D L1 As shown, in the first configuration, the lumen 225 can have a generally constant diameter along its entire length, or substantially its entire length.

[0036] The geometry of the lumen 225 can be adjusted to vary the flow rate of blood therethrough. In some embodiments, the diameter of the lumen 225 at a particular location is adjusted. For example, referring to FIG. 2B, the diameter of the lumen 225 is reduced in a central portion of the lumen 225 compared to the first configuration shown in FIG. 2A, resulting in an hourglass-shaped configuration. The diameter of the lumen at the narrowest part of the hourglass is D. L2This is the first diameter D L1 Generally smaller than

[0037] In other embodiments, the diameter of lumen 225 is adjusted along its entire length. For example, referring to FIG. 2C, the diameter of lumen 225 is reduced along its entire axial length as compared to the first configuration shown in FIG. 2A, thereby maintaining a generally cylindrical shape but having a second configuration that is smaller in diameter than the first configuration. The diameter of lumen 225 is generally constant along its length and is adjusted to D L3 This is the first diameter D L1 Generally smaller than the diameter D L2 The diameter of lumen 225 can be the same as or different from that of lumen 225. The geometry of lumen 225 can be adjusted in other ways as well. For example, in other embodiments, the diameter of lumen 225 generally remains the same, but the diameter of one or more lumen orifices is reduced.

[0038] In some embodiments, the geometry of lumen 225 can be adjusted to increase the flow of blood therethrough. For example, the diameter of lumen 225 can be enlarged. As shown in FIG. 2D, the diameter of lumen 225 can be enlarged from a first diameter D L1 Diameter D is larger than L4 2D, lumen 225 is shown to have a generally constant diameter along its entire axial length, however, lumen 225 may alternatively have an inverted hourglass shape (e.g., the diameter of lumen 225 at the midsection is larger than the diameter of the lumen orifice).

[0039] As shown in FIG. 2E, when the system 200 is implanted across the septal wall S in a first configuration (e.g., the configuration shown in FIG. 2A), the lumen 225 allows a first amount (e.g., flow rate, volume, etc.) of blood to flow between the LA and the RA. FIG. 2F shows the system 200 implanted across the septal wall S in a second configuration (i.e., the configuration shown in FIG. 2C). Compared to the first configuration (i.e., the configuration shown in FIG. 2A), the second configuration results in a decrease in blood flow between the LA and the RA. As one skilled in the art can appreciate, in some embodiments, the system 200 can assume an hourglass configuration (i.e., the configuration shown in FIG. 2B) to decrease blood flow. Similarly, the system 200 can assume a configuration shown in FIG. 2D to increase the flow rate of blood between the LA and the RA.

[0040] Thus, the present technology provides adjustable inter-atrial shunt systems that can adjust the geometry of the flow lumen and / or lumen orifice to vary the flow rate of blood therethrough. In particular, Figures 3A-23C illustrate adjustment of the lumen geometry, and Figures 24-32 illustrate adjustment of the orifice geometry. The systems can be adjusted using a variety of actuation mechanisms, which are described in more detail below.

[0041] i. Stent-Like Actuating Assembly 3A is a schematic diagram of coupled working elements (first working element 305 and second working element 310) forming part of an inter-atrial shunt device configured in accordance with an embodiment of the present technology. The first working element 305 can have an original geometric configuration (e.g., D1) different from that of the second working element 310 (D2). As provided above, D1 can refer to the hydraulic diameter or equivalent diameter of the first working element 305, the diameter of the first working element 305 at a particular location (e.g., the orifice of the lumen, the center point of the lumen, etc.), the diameter of the first working element 305 along a portion of its length, and / or another dimension. Similarly, D2 can refer to the hydraulic diameter or equivalent diameter of the second working element 310, the diameter of the second working element 310 at a particular location, the diameter of the second working element 310 along a portion of its length, and / or another dimension. The first and second working elements 305, 310 can be coupled together to form a working assembly 300. Direct coupling of the at least two actuating elements can be achieved by sutures, adhesives / glues, crimps / rivets, interference fits, welding / soldering, or other techniques known to those skilled in the art. Indirect coupling of the at least two actuating elements can be achieved by direct coupling of each actuating element to a common intermediate element. Following assembly, the actuating assembly 300 may be configured at a first temperature (e.g., room temperature, body temperature, etc.) to assume a geometry that is in equilibrium between the original geometric configurations of the individual actuating elements (e.g., D1>D C Actuation of the first actuating element 305 can cause the flow control element to have a geometry (D L For example, actuation of the first actuation element causes the geometry of the flow control element to expand (e.g., D L >D C Actuation of the second actuating element 310 causes the flow control element to move to a second geometry (D S For example, actuation of the second actuation element causes the geometry of the flow control element to shrink (e.g., D S <D C ).

[0042] In some embodiments, at least one actuation element includes an insulating element. For example, the actuation element can be coated with an electrically insulating material and / or a thermally insulating material. In some embodiments, the insulating element is flexible. The insulating element can be a polyimide (e.g., Kapton®), a synthetic polymer (e.g., polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE)), a thin-film ceramic coating (e.g., TiO x ), or urethane (e.g., ChronoFlex®), or another suitable material known to one of skill in the art. The polymeric insulating elements can have dimensions (e.g., coating thickness) that are, for example, about 50 microns, about 75 microns, about 100 microns, about 150 microns, about 300 microns, or about 1 millimeter. The ceramic insulating elements can have dimensions (e.g., layer thickness) that are, for example, about 5 nm, about 10 nm, about 100 nm, about 200 nm, about 300 nm, about 400 nm, or about 500 nm. The insulating elements can have dimensions greater than, less than, or between any of the foregoing dimensions.

[0043] FIG. 3B is a schematic diagram of coupled working elements forming part of an inter-atrial shunt device configured in accordance with an embodiment of the present technology. In the example of FIG. 3B, the working elements are coupled by nesting one inside the other (e.g., an element with a larger original geometric configuration nests within an element with a smaller original geometric configuration). In some embodiments, the first and second actuators comprise elongate members (e.g., stents, scaffolds, etc.). The geometries (e.g., cross-sectional areas) of the elongate members can be constructed to have different sized configurations. For example, the first member has a cross-sectional diameter (D B ) larger than the cross-sectional diameter (D A) to form an adjustable composite element (e.g., a flow control element or portion thereof). The larger member 305a can be deformed and positioned (e.g., compressed) within the smaller member 310a. The coupling of the first and second members can form a nested arrangement 300a. In some embodiments, the nested arrangement includes a coaxial or concentric arrangement of multiple stents. The geometry of the flow control element can have an equilibrium geometry (e.g., D A >D 入れ子式 >D B Like, D 入れ子式 ). The larger member 305a is actuated (e.g., heated) to return it to its original geometric configuration (D A ) the composite actuation assembly 300a will change in size, e.g., by inducing a thermoelastic recovery that is intended to return the composite actuation assembly 300a to a size of, e.g., D 入れ子式 Bigger, D A Similarly, the smaller member 310a is actuated (e.g., heated) to induce thermoelastic recovery, causing it to return to its original geometric configuration (D B ), the composite flow control element 300a changes in size, e.g., to D 入れ子式 Smaller, D Bor greater. In some embodiments, an increase in granularity of geometry change is achieved by combining more than two actuating elements into the composite structure (e.g., multiple stents nested within one another). Actuating any one (or any combination) of the elements (e.g., stents) drives the composite structure to a different, predefined geometric configuration. In one embodiment, the actuating elements can be assembled as they progress from inside to outside the composite structure (e.g., from a maximum to a minimum of original geometric configurations). For example, the assembly can be such that the minimum original geometric configuration is the outermost actuating member within the composite structure. The outermost element (e.g., the element with the smallest geometry shaped), when actuated, exerts a force on the composite structure that causes it to reduce to its minimum geometric configuration. This can be achieved because the non-actuated (e.g., non-heated) elements can be in a relatively malleable state and therefore can experience a complementary movement as a result of the increased force exerted by the actuated elements. When the intermediate elements are actuated, the composite structure achieves an intermediate geometry configuration with the non-actuated (i.e., slave) elements being driven by the actuated elements and moving to objects complementary to the actuated elements. When the innermost elements are actuated, the composite structure can achieve a maximum geometry configuration with the non-actuated (i.e., slave) elements being driven by the actuated elements and moving to objects complementary to the actuated elements. In some embodiments, at least two actuating elements are actuated substantially simultaneously. In some embodiments, the simultaneous actuation of at least two actuating elements provides greater granularity and / or precision in the movement of the flow control elements than is possible with respect to actuation of a single actuating element.

[0044] 4A-4C are schematic diagrams of combined working element portions forming part of an inter-atrial shunt device configured in accordance with an embodiment of the present technology. The individual working elements can be constructed from shape memory material and can be manufactured to have similar overall shapes, patterns, and / or dimensions. With joint reference to FIGS. 4A-4C, the working elements (e.g., stents) can be formed by wire forming, laser cutting, or another suitable process. A first working element 405 can be manufactured into a first (original) geometric configuration and has a first cell size C. A and a series of repeating cells 406 having a total (e.g., cumulative) unwrapped length LA (e.g., circumference when constructed into a cylindrical shape). When wrapped about a central axis, the first actuating element 405 has a first cross-sectional diameter D A The second actuation element 407 can be fabricated in a second geometric configuration and can include a geometric configuration having a second cell size C B and the total (e.g., cumulative) unwrapped length L B (e.g., a circumference when constructed in a cylindrical shape). When wrapped about a central axis, the second actuating element 407 has a second cross-sectional diameter D B In some embodiments, the first and second actuating elements include a geometric configuration having a different geometric configuration, for example, C A >C B , L > L B , D A >D B etc. In an embodiment, the first and second actuating elements 405, 407 have similar patterns to facilitate direct coupling or features to promote indirect coupling via one or more intermediate members.

[0045] The first and second actuating elements 405, 407 can include segments (404 and 409) configured to allow for coupling to another actuating element or to another component of the device. In some embodiments, the portions for coupling include longitudinal struts. In embodiments, the segments for coupling can be maintained at a substantially fixed dimension (e.g., length) before and after construction of the actuating elements. In embodiments, two or more actuating elements can be coupled together by sutures, adhesives / glues, rivets / crimps, welding, encapsulating sleeves, or via other methods. In some embodiments, at least one of the coupling portions (e.g., 404 or 409) includes an insulating element. In some embodiments, the insulating element provides electrical and / or thermal insulation between the coupled actuating elements. By coupling two or more actuating elements, as best seen in FIG. 4C, a composite element 415 can be created, which at a given temperature (e.g., room temperature) has a composite cell size C C and having an equilibrium geometric configuration characterized by at least a series of repeating cells 412 having a total (e.g., cumulative) unwrapped length L C When wrapped about the central axis, the compound actuating element 415 has a compound cross-sectional diameter D C In embodiments, this wrapped compound working element can function as a flow control element forming part of an inter-atrial shunt device, configured in accordance with an embodiment of the present technology. In embodiments featuring one relatively large and one relatively small working element, the geometry of the compound element can have a size (i.e., C) that is between the values ​​of the individual elements. A >C C >C B ;D A >D C >D B ;L A >L C >L B )

[0046] One or more elements of a composite flow control element can be actuated to impart a change in the geometry of the composite structure. For example, as an actuated element grows, the geometric characteristics of the composite element change to a new cross-sectional diameter D N1 (herein, D N1 >D C Conversely, when the actuating elements become smaller, the geometric properties of the composite elements change with the new cross-sectional diameter D N2 (Here, D N2 <D C ).

[0047] FIG. 5A is a flat pattern view of interlocking actuating elements that can be combined to form a part of an interatrial shunt device, configured in accordance with an embodiment of the present technology. In particular, FIG. 5A shows a first actuating element 505 and a second actuating element 510. In some embodiments, the first actuating element 505 and / or the second actuating element 510 are stents or stent-like structures that are combined to form an actuating assembly. In embodiments, the first actuating element 505 and / or the second actuating element 510 are constructed from a shape memory material. The actuating assembly can be actuated to move through two or more geometric configurations to change the characteristics of the flow rate of fluid through the shunt device. The first actuating element 505 includes both an arm element 502 and a jig element 503, where the arm element 502 terminates in an eyelet opening 518 and the jig element 503 terminates in an eyelet opening 515. Similarly, the second actuating element 510 includes both an arm element 507 and a jig element 508, with the arm element 507 terminating in an eyelet opening 519 and the jig element 508 terminating in an eyelet opening 516. The patterns and / or shapes of the first and second actuating elements 505, 510 may be similar. The shapes and / or geometries of the first and second actuating elements 505, 510 can be constructed into different configurations during pre-processing steps, as described in more detail below. Prior to bonding of the first and second actuating elements 505, 510, the first and second actuating elements 505, 510 can be manipulated into shapes and / or geometries different from their original geometric configurations (e.g., by flattening the shape memory alloy structures while they are at a temperature where the material is at least partially in the martensite or R-phase and thus relatively malleable). In an embodiment, the first and second actuating elements 505, 510 may be joined along a backbone that corresponds to the peaks of the jig elements 503 and 508 (e.g., by fastening a series of eyelets 515 and 516 together using sutures or another connecting means).4A-4C, the first and second working elements 505, 510 are coupled back-to-back, or "end-to-end," where a first end of the first working element 505 is coupled to a second end of the second working element 510, and the first working element 505 is not nested within (e.g., does not generally overlap with) the second working element 510. This operation represents an initial coupling operation, which is a step in a process of using the first and second working elements 505, 510 to create a working assembly that is part of an inter-atrial shunt device.

[0048] Additional bonding steps can be performed to create an actuating assembly from the first and second actuating elements 505, 510. For example, during a secondary bonding step, the flat configuration of the stent structure (i.e., as shown in FIG. 5A) can be wrapped around a central axis and attached to itself to create a structure defining a lumen or passageway. For example, the area defined by eyelet openings 504 and 509 (already bonded / joined) is then bonded to the area defined by eyelet openings 520 and 521 (also already bonded / joined). Following this operation, the composite element can assume a rounded profile (e.g., a cylindrical profile).

[0049] FIG. 5B provides additional schematic views of the first and second actuating elements 505, 510 before they are coupled together to form an actuating assembly, thereby illustrating their manufacturing geometry (e.g., their preferred geometry). In particular, FIG. 5B illustrates a single element pair isometric view, a dual element pair 2D view, a front view, a side view, and an isometric view of the first and second actuating elements 505, 510. As noted above, the first and second actuating elements 505, 510 can be constructed (e.g., formed or manufactured) in different configurations prior to coupling. The illustrated geometric configurations include arm elements 502 and 507 that bend off-axis (i.e., in the "off-page" direction when viewing FIG. 5A ) from jig elements 503 and 508. In some embodiments, the off-axis bend angle for arm element 502 can be different relative to the off-axis bend angle for arm element 507 of second actuating element 510. For example, referring to a 2D view of the dual element pair, arm elements 502 and 507 are bent off-axis, with arm 502 of first actuating element 505 bent at a relatively larger (e.g., more open) angle and arm 507 of second actuating element 510 bent at a relatively smaller / tighter (e.g., more closed) angle. As a result, eyelet openings 518 of first actuating element 505 are relatively closer together (defining a smaller diameter) and eyelet openings 519 of second actuating element 510 are relatively further apart (defining a larger diameter).

[0050] In some embodiments, a third coupling operation can be performed to form a composite actuation assembly including both the first and second actuation elements 505, 510. In some embodiments, this operation involves coupling the bent arms 502 and 507 of the first and second actuation elements 505, 510 using a flexible connection (e.g., an elastic polymer, a stretchable / flexible material, etc.). For example, a flexible suture material can be utilized to couple the eyelet opening 518 on the first actuation element 505 with its assembled mating eyelet opening 519 on the second actuation element 510. Upon completion of this third coupling operation, the bending angles of the arms 502 and 507, respectively, can change and reach an equilibrium angular position. As with other coupling operations described herein, in embodiments, the coupling can be performed in a manner that maintains and / or establishes electrical and / or thermal insulation between the first actuation element 505 and the second actuation element 510. After or before this third bonding operation, a membrane material (not shown) can be joined at the interface with the composite structure to provide an enclosed channel (e.g., an enclosed lumen) through which fluid can pass through the flow control element.

[0051] In one example of a method of use, following the third coupling operation described above, a composite actuating assembly (e.g., which may also be referred to as a "flow control element") comprised of the first and second actuating elements 505, 510 can be compressed into a delivery system (e.g., a catheter delivery system) (with or without integration into an interatrial shunt system) and delivered to a patient's body. In an embodiment, once positioned in a desired location, the composite actuating assembly can be deployed and manually expanded (e.g., using inflation of a catheter balloon) to a neutral position. In an embodiment, the composite actuating assembly is in a material state (e.g., at least partially in a martensite phase) that is relatively malleable such that it is deformable from a delivery configuration to a neutral configuration. In an embodiment, the composite actuating assembly is manufactured such that at least a portion of the composite actuating assembly remains in a material phase that is relatively malleable and deformable (e.g., a Nitinol alloy remains at least partially in a martensite or R-phase) at both a first temperature (e.g., room temperature) and a second temperature (e.g., body temperature) that is higher than the first temperature.

[0052] FIG. 6 provides schematic diagrams of various configurations of a composite actuation assembly formed by combining the first and second actuation elements 505, 510 shown in FIGS. 5A and 5B. FIG. 6 also illustrates generally one example of an operational mode that can be used to actuate the actuation assembly. Shown in FIG. 6 are an isometric view of a single element pair, a 2D view of a dual element pair, a front view of the complete structure, a side view of the complete structure, and an isometric view of the complete structure. In FIG. 6, the first row of the table shows the actuation assembly in a neutral configuration (e.g., after balloon inflation or other manipulation), the second row shows the actuation assembly in an expanded configuration that creates a relatively small lumen for fluid flow rate, and the third row of the table shows the actuation assembly in a retracted configuration that creates a relatively large lumen for fluid flow rate. For clarity, the first and second actuating elements 505, 510 are not shown as physically coupled (e.g., the actuating elements are shown slightly separated in the figures without stitches, welds, flexible connections, etc.), but the configuration of the first and second actuating elements 505, 510 in each figure represents the mechanical behavior of a coupled actuating assembly.

[0053] As shown in FIG. 6, the lumen of the working assembly can vary in shape along its elongated axis (i.e., the horizontal blood flow axis of FIG. 6 in the Dual Element 2D View and Full Front View). In a configuration where the minor axis cross-sectional diameter of the lumen is at its largest (FIG. 6, third row), the lumen is substantially cylindrical along its elongated axis (best visualized in the Dual Element 2D View and Full Side View). In a configuration where a portion of the lumen's minor axis cross-sectional diameter is relatively smaller, the lumen can assume different shapes (e.g., hourglass, funnel) along its major axis (as shown in the first and second rows of FIG. 6).

[0054] The functions of the exemplary embodiments shown in FIGS. 5A - 6 may be similar to those of other embodiments of the actuation assembly described herein. In a first state, for example, the actuation assembly may be configured such that its minimum minor - axis cross - sectional diameter is D1, as shown in the first row of FIG. 6. To change the configuration of the actuation assembly to a geometry that allows for a relatively low flow rate through the lumen, the first actuation element 505 can be actuated by applying energy to this element (e.g., by heating the element above its phase - transition temperature) in such a way that the arm 502 is moved towards a configuration shaped into a relatively more open geometry. Since these arms are coupled by a flexible connection to the arms 507 of the second actuation element 510, and since the second actuation element 510 is not substantially heated and remains in a relatively malleable material state, the arms 507 are operated to be in a position corresponding to the position of the arm 502, as shown in the second row of FIG. 6. This actuation causes the geometry of the lumen of the actuation assembly to change, and the minimum minor - axis cross - sectional diameter moves to a value of D2 (where, as shown in the second row of FIG. 6, D2 < D1). Similarly, to change the configuration of the actuation assembly to a geometry that allows for a relatively high flow rate through the lumen, the second actuation element 510 can be actuated by applying energy to this element (e.g., by heating the element above its phase - transition temperature) in such a way that the arm 507 is moved towards a configuration shaped into a relatively more closed geometry. Since these arms 507 are coupled by a flexible connection to the arms 502 of the first actuation element 505, and since the first actuation element 505 is not substantially heated and is in a relatively malleable material state, the arm 502 is operated to be in a position corresponding to the position of the arm 507, as shown in the third row of FIG. 6. This actuation causes the geometry of the lumen of the actuation assembly to change, and the minimum minor - axis cross - sectional diameter moves to a value of D3 (where, as shown in the third row of FIG. 6, D3 > D1).

[0055] In additional embodiments similar to those shown in FIGS. 5A-6, the coupling geometry / configuration between the individual actuation element structures 505 and 510 may be different. For example, the actuation elements may be coupled in a manner such that one element is substantially above the other (e.g., rather than being connected back to back). Alternatively, or in addition, one element may be nested within a bend in another element (e.g., within a corner created by bending the arm 502 relative to the jig element 503). Any number of actuation element structures may be coupled together and used. In some embodiments, utilizing a greater number of actuation elements is useful as it allows for greater precision and / or granularity in altering the geometry of the actuation assembly.

[0056] FIG. 7 is a schematic diagram of coupled actuating elements configured according to another embodiment of the present technology. The structure of FIG. 7 includes a first actuating element 750 and a second actuating element 760 (e.g., a stent-like structure). The first and second actuating elements 750, 760 each include arm elements 751 and 757, respectively, and jig elements 752 and 758, respectively. The arm elements 751 and 757 terminate in eyelet openings 759 and 769. The jig elements are comprised of both "peaks" 755 and "valleys" 756. As in the exemplary embodiment shown in FIG. 5A, the individual stent structures can be constructed into different geometric configurations during manufacturing and assembly and then manipulated away from their original geometry prior to coupling. The first and second actuating elements 750, 760 can be coupled together to form a composite actuating assembly structure by nesting the peaks 755 of the first actuating element 750 near the valleys 756 of the second actuating element 760. The composite structure can be affixed using sutures, adhesives / glues, crimps / rivets, welding, material coated sleeves, or other connection techniques known to those skilled in the art. This operation represents an initial bonding operation that is a step in the process of using the first and second working elements 750, 760 to create a working assembly that is part of an interatrial shunt device. The composite structure can be formed into a generally cylindrical working assembly that has a neutral configuration at body temperature and then manipulated through various configurations by selectively heating the first working element 750 or the second working element 760 above their respective transition temperatures, as described in detail above with respect to FIG.

[0057] ii. An actuation assembly having an elongated actuation element In addition to the stent-like actuating elements described with respect to Figures 3A-7, the present technology also includes actuating assemblies having other types of actuating elements. For example, the present technology includes adjustable shunts having elongated actuating elements (e.g., wires, cables, spindles, struts, etc.). In some embodiments, the elongated actuating elements are constructed from shape memory materials that can be thermally manipulated to adjust the geometry of the adjustable shunt to change the flow rate of fluid therethrough.

[0058] For example, FIGS. 8A-8F illustrate aspects of an adjustable interatrial system 800 ("system 800") including a plurality of spindle-like shape memory actuation elements and configured in accordance with selected embodiments of the present technology. Referring initially to FIG. 8A, which is a cross-sectional view of system 800 implanted across a septal wall S in a first configuration, system 800 includes a frame 820 deployable across the septal wall S. Frame 820 can include a first end positionable within the RA and a second end positionable within the LA. Frame 820 can include RA anchor element 824 and / or LA anchor element 826 that secure frame 820 to septal wall S. Frame 820 can include a superelastic material such as Nitinol or another suitable material (e.g., an alloy derivative of Nitinol, cobalt chrome, stainless steel, etc.). In embodiments in which the frame 820 is constructed from Nitinol, Nitinol has a transition temperature below body temperature such that the Nitinol is in an austenitic material state when implanted, making the frame 820 resistant to changes in geometry even when heated. Certain aspects of the frame 820 are omitted from FIG. 8A for clarity. For example, in some embodiments, the frame 820 can include an outer layer for engaging the septal wall S and an inner layer or membrane (e.g., similar to the outer and inner layers described below with respect to FIGS. 14-16D) that defines the lumen 802. In some embodiments, the frame 820 has a stent-like scaffold structure. When secured to the septal wall S, the system 800 fluidly couples the LA and RA and allows blood flow therebetween via the lumen 802.

[0059] The system 800 includes a plurality of first actuating elements 806 (only one is shown in FIG. 8A ) and a plurality of second actuating elements 808 (only one is shown in FIG. 8A ), which extend between the RA side and the LA side of the system 800. The first actuating element 806 and the second actuating element 808 can be disposed within a membrane (not shown) that defines the lumen 802. The first and second actuating elements 806, 808 can be wire-like spindles that extend generally linearly and parallel to the central longitudinal axis of the lumen 802. In some embodiments, the system 800 includes the same number of first actuating elements 806 (e.g., three first actuating elements 806) and second actuating elements 808 (e.g., three second actuating elements 808). However, in other embodiments, the number of first actuating elements 806 can be different from the number of second actuating elements 808. The first actuating element 806 and the second actuating element 808 can each include opposing ends that are secured to the frame 820 by welding, soldering, riveting, gluing, sewing, etc. For example, the first actuating element 806 and the second actuating element 808 can be secured to and extend between first and second ends of the frame.

[0060] 8B, which is a cross-sectional view of lumen 802 taken across its axial length, the first and second actuating elements 806, 808 can be disposed about lumen 802 in an alternating fashion between the first actuating element 806 and the second actuating element 808. In some embodiments, the first and second actuating elements 806, 808 can be encased in a biocompatible material and / or membrane 810 (e.g., ePTFE), which can at least partially define the periphery of lumen 802. The membrane 810 can be at least partially flexible to accommodate movement of the first and second actuating elements 806, 808 as they transition between their deformed and manufactured configurations, as described below.

[0061] The first and second actuating elements 806, 808 can be composed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the first and second actuating elements 806, 808 can be transitionable between a first material state (e.g., martensitic state, R-phase, etc.) and a second state (e.g., shape memory state, austenitic state, etc.). In the first state, the first and second actuating elements 806, 808 can be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the first and second actuating elements 806, 808 can have a preference for a particular manufacturing geometry (e.g., shape, length, and / or size). By applying energy to the spindle to heat the spindle above a transition temperature, the first and second actuating elements 806, 808 can transition between the first and second states. In some embodiments, the transition temperatures of both the first and second actuating elements 806, 808 are greater than average body temperature. Thus, both the first operative element 806 and the second operative element 808 are manufactured such that when the system 800 is implanted within the body, they are in a deformable first material state.

[0062] If the actuating elements (e.g., first actuating element 806) are deformed while in a first material state, heating the actuating elements (e.g., first actuating element 806) above their transition temperature will cause the actuating elements to transition from their deformed shape toward their manufactured geometry by transitioning to a second material state. Heat can be applied to the actuating elements by RF heating, resistive heating, etc. In some embodiments, the first actuating element 806 can be selectively heated independently of the second actuating element 808, and the second actuating element 808 can be selectively heated independently of the first actuating element 806 (e.g., the first and second actuating elements are thermally and / or electrically isolated). For example, in some embodiments, the first actuating element 806 is on a first electrical circuit for selectively and resistively heating the first actuating element 806, and the second actuating element 808 is on a second electrical circuit for selectively and resistively heating the second actuating element 808. As described in more detail below, selectively heating first actuating element 806 causes the diameter of lumen 802 to decrease, and selectively heating second actuating element 808 causes the diameter of lumen 802 to increase.

[0063] To drive the actuation of the system 800, the first actuating element 806 and the second actuating element 808 are generally fabricated to have different fabricated geometries. Referring now to FIG. 8E, in some embodiments, the first actuating element 806 can have a generally linear fabricated geometry having a length X. Thus, when the first actuating elements 806 are heated above their transition temperature, they move toward or assume a shape shown in solid lines in FIG. 8E having a length X, regardless of their shape prior to heating. However, while in a deformable first (e.g., martensitic) state and / or during attachment to the frame 820, the first actuating elements 806 can stretch to a distance D (shown in dashed lines) and have a second length greater than X (e.g., a length equal to X+D). As described above, after heating the first actuating elements 806 above their transition temperature, the first actuating elements contract and move toward or assume a fabricated geometry having a length X. The second actuating elements 808 can also have a manufactured geometry, which in some embodiments can have a length that is generally greater than or equal to the distance X+D. The second actuating elements 808 can be deformable when in a first (e.g., martensitic) state. However, as described below, the second actuating elements 808 can be manufactured to move toward or assume the manufactured geometry shown in FIG. 8E when heated above their transition temperature. The second actuating elements 808 can assume their manufactured geometry or another partially deformed shape when attached to the frame 820.

[0064] 8A and 8B, system 800 is shown in a first configuration in which lumen 802 has a first diameter D1 at its pinched portion (e.g., the narrowest portion of the generally hourglass shaped lumen). In this configuration, at least first actuating elements 806 are in a first (e.g., martensitic) state and are deformed (e.g., stretched) relative to their manufactured shape. In the illustrated configuration, lumen 802 has a generally circular cross-sectional area, although other configurations are possible without departing from the scope of the present technology.

[0065] 8C and 8D show the system 800 in a second configuration different from the first configuration. For example, FIG. 8C is a cross-sectional view of the system 800 implanted across the septal wall S in the second configuration, and FIG. 8D is a cross-sectional view of the lumen 802 taken across its axial length. In particular, in the second configuration, the system 800 has been actuated to transition the first actuating elements 806 from a first (e.g., martensite) material state to a second (e.g., austenite) material state relative to the first configuration shown in FIG. 8A. Because the first actuating elements 806 have stretched (e.g., lengthened) relative to their manufactured geometry while in the first state, heating the first actuating elements 806 above a transition temperature causes the first actuating elements 806 to contract in length and move toward their manufactured geometry (e.g., having a length X, as shown in FIG. 8E). As the first actuating elements 806 contract in length toward their manufactured geometry, they retract a portion of the frame 820 (shown in dashed lines) inwardly from a first position A to a second position B. This causes second actuating elements 808, still in their deformable first (e.g., martensitic) state because they have not been heated above their transition temperature, to hinge or otherwise bend inwardly toward the central longitudinal axis of lumen 802. This causes the diameter of lumen 802 at the pinch point to decrease to a second diameter D2 that is smaller than first diameter D1. When implanted in a human heart, the decrease in diameter of lumen 802 (e.g., by transitioning from the first configuration to the second configuration) is expected to reduce the flow of blood from the LA to the RA.

[0066] The system 800 can return to the first configuration shown in FIGS. 8A and 8B by returning the first actuating element 806 to the deformable first state (e.g., by allowing the first actuating element 806 to cool below a transition temperature) and heating the second actuating element 808 above their transition temperature. Heating the second actuating elements 808 above their transition temperature moves the second actuating elements 808 toward their manufactured geometry ( FIG. 8A ), which in turn pushes the frame 804 from the second position B to the first position A, causing the first actuating element 806 to deform (e.g., stretch) and expand the diameter of the lumen 802. Thus, the system 800 can selectively transition between various configurations / geometry by selectively actuating either the first actuating element 806 or the second actuating element 808. After actuation, the system 800 can be configured to substantially retain a given configuration until further actuation of the opposing actuating element. In some embodiments, additional sizes and / or geometries of the lumen 802 can be achieved by selectively heating a subset of the first actuating element 806 and / or the second actuating element 808. In some embodiments, the system 800 can include additional actuating elements (e.g., a third actuating element) that have a different manufactured geometry than either the first actuating element or the second actuating element and, therefore, can drive the lumen into additional configurations upon actuation.

[0067] FIG. 8F illustrates a delivery configuration of the system 800. In the delivery configuration, the overall profile of the system 800 can be reduced by folding, flattening, or otherwise crimping the frame 820 including the RA anchor element 824 and the LA anchor element 826. In the delivery configuration, the first actuating element 806 and the second actuating element 808 can retain their respective lengths that the device assumes when deployed in the first configuration. For example, the first actuating element 806 can have their deformed (e.g., stretched) geometry with a length equal to X+D (FIG. 8E), and the second actuating element 808 can also have their manufactured geometry with a length equal to X+D (FIG. 8E). In other embodiments, the first actuating element 806 and / or the second actuating element 808 can use other shapes or configurations while in the delivery configuration. The crimped system 800 can be inserted into a catheter (not shown) for transvascular delivery to the heart and deployment across the septal wall. Upon deployment of system 800 from a catheter, the superelastic properties of frame 820 allow system 800 to expand. For example, upon deployment of system 800, system 800 may assume a first configuration as shown with reference to Figures 8A and 8B.

[0068] FIG. 9 is a cross-sectional, partial schematic view of an adjustable inter-atrial shunt system 900 ("system 900") including a helically wrapped elongated working element and configured in accordance with selected embodiments of the present technology. System 900 includes a shunt element 910, an anchor element 920, an adjustable inner lumen 930, and a working assembly 940. The shunt element 910 is configured to extend between the LA and RA of the heart when implanted across the septal wall S. The shunt element 910 can have a generally toroidal shape including an outer surface 912, an inner surface 914, a proximal surface 916a, and a distal surface 916b. The outer surface 912 (which can also be referred to as a "frame") can engage native cardiac tissue when implanted in the heart. For example, in the illustrated embodiment, the system 900 is shown implanted in a human heart with the outer surface 912 engaging the septal wall S. The inner surface 914 can include a membrane that at least partially defines an adjustable lumen 930. As shown, when the system 900 is implanted in the heart, the lumen 930 fluidly connects the LA and the RA. The proximal surface 916a is configured to reside in the RA and the distal surface 916b is configured to reside in the LA. One or more portions of the shunt element 910 can be constructed from or coated with a biocompatible and / or anti-thrombogenic material (e.g., ePTFE). In some embodiments, one or more portions of the shunt element 910 (e.g., the membrane forming the inner surface 914) are constructed at least in part from a flexible or malleable material.

[0069] In some embodiments, the outer surface 912, the inner surface 914, the proximal surface 916a, and the distal surface 916b of the shunt element 910 define a generally toroidal shaped chamber 950. The chamber 950 can be fluidly insulated from the interior of the lumen 930. The chamber 950 can also be fluidly insulated from the environment surrounding the system 900 by the material encasing the shunt element 910. Thus, in some embodiments, the system 900 is configured to prevent blood from flowing into the chamber 950. In some embodiments, the chamber 950 can include a compressible and / or displaceable liquid, gas, and / or gel. Thus, when the diameter of the lumen 930 is adjusted (as described below), the liquid or gas can compress, expand, and / or displace. In other embodiments, the shunt element 910 is substantially solid throughout its cross section, such that the chamber 950 is not present. In such embodiments, the shunt element 910 comprises an at least partially compressible and expandable material to accommodate changes in diameter of the lumen 930. The anchor element 920 is configured to secure the system 900 at a desired location within the heart. For example, as shown, the anchor element 920 can secure the system 900 to native cardiac tissue, such as the septal wall S. In some embodiments, the anchor element 920 can include a right atrial anchor and / or a left atrial anchor. The anchor element 920 can extend from and / or be integral with one or more sides of the shunt element 910.

[0070] The actuating assembly 940 is configured to selectively adjust the diameter of the lumen 930 to control the flow rate of blood therethrough. In the illustrated embodiment, the actuating assembly 940 includes a first actuating element 942 and a second actuating element 944. The first actuating element 942 and the second actuating element 944 wrap around the lumen 930 defined by the inner surface 914. For example, the first actuating element 942 and the second actuating element 944 have a generally helical configuration with the lumen 930 disposed within the center of the helix. The first actuating element 942 and the second actuating element 944 can be embedded within a membrane defining the lumen and / or otherwise coupled to the inner surface 914 to drive radial movement of the inner surface 914. For example, in some embodiments, the inner surface 914 has a thickness and the first actuating element 942 and the second actuating element 944 are embedded within the thickness of the inner surface 914. In some embodiments, the system 900 includes one or more fluidly, thermally, and / or electrically isolated channels 946 that extend in a generally helical orientation around the inner lumen 930. The first actuating element 942 and the second actuating element 944 can be housed within the channels 946. The channels 946 can be positioned within the chamber 950, embedded within the thickness of the inner surface 914, and / or positioned within the lumen 930 itself. In some embodiments, the system 900 can include a first channel for housing the first actuating element 942 and a second channel for housing the second actuating element 944. In other embodiments, a single channel houses both the first actuating element 942 and the second actuating element 944. The one or more channels 946 can be sized and shaped to protect the actuating elements from an environment external to the system 900, and further can electrically and / or thermally insulate the first actuating element 942 from the second actuating element 944.

[0071] The first actuating element 942 includes a proximal end region 942a that is fixed to the system 900 and a distal end region 942b that is fixed to the system 900. Similarly, the second actuating element 944 includes a proximal end region 944a that is fixed to the system 900 and a distal end region 944b that is fixed to the system 900. The illustrated embodiment shows the proximal end regions 942a, 944a fixed to a portion of the anchor element 920 and the distal end regions 942b, 944b fixed to the shunt element 910. However, one skilled in the art will understand that the first actuating element 942 and the second actuating element 944 can be fixed to any number of structures of the system 900 without departing from the scope of the present technology.

[0072] The first and second actuating elements 942, 944 may be constructed of any material suitable for dynamically adjusting the diameter of the lumen 330. For example, in some embodiments, the first and second actuating elements 942, 944 may be constructed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the first and second actuating elements 806, 808 may be transitionable between a first material state (e.g., a martensitic state, R-phase, etc.) and a second material state (e.g., a shape memory state, an austenitic state, etc.). In the first state, the first and second actuating elements 806, 808 may be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the first and second actuating elements 806, 808 may have a preference for a particular manufacturing geometry (e.g., shape, length, and / or size). The first and second actuating elements 942, 944 can be transitioned between the first state and the second state by providing energy to the first actuating element 942 and / or the second actuating element 944 to heat (e.g., resistively heat) the first actuating element 942 and / or the second actuating element 944 above a transition temperature. In some embodiments, the transition temperature of both the first actuating element 942 and the second actuating element 944 is greater than average body temperature. Thus, when the system 900 is implanted within the body, both the first actuating element 942 and the second actuating element 944 are fabricated to be in a deformable first state until they are heated (e.g., activated).

[0073] At least one of the first actuating element 942 and the second actuating element 944 can be at least partially deformed relative to its manufactured geometry when implanted. For example, if the first actuating element 942 is deformed relative to its manufactured geometry, actuating the first actuating element 942 (e.g., by heating it above its transition temperature) can move the first actuating element 942 toward its manufactured geometry, tightening the first actuating element 942 and decreasing the diameter of the lumen 930. If the second actuating element 944 is deformed relative to its manufactured geometry, actuating the second actuating element 944 (e.g., by heating it above its transition temperature) can loosen the second actuating element 944 and increase the diameter of the lumen 930.

[0074] 10A and 10B show aspects of an adjustable inter-atrial system 1000 ("system 1000") configured in accordance with selected embodiments of the present technology. System 1000 is generally similar to system 900 described in detail above with reference to FIG. 9. For example, system 1000 can include a shunt element 1010 having an outer surface (not shown) and an inner surface 1014, an anchor element (not shown), an adjustable lumen 1030, and an actuation assembly 1040. The inner surface 1014 can include a flared proximal end 1014a configured to reside in the RA of the heart, and a flared distal end 1014b configured to reside in the LA of the heart.

[0075] 10A, the actuating assembly 1040 includes a first actuating element 1042 and a second actuating element 1044. Similar to system 900, the first actuating element 1042 and the second actuating element 1044 can be generally helical coils wrapped around a lumen 1030 defined by an inner surface 1014 (e.g., embedded within a membrane defining the inner surface 1014). For example, the first actuating element 1042 and the second actuating element 1044 have a generally spiral-shaped configuration with the lumen 1030 disposed within the center of the spiral. In the illustrated embodiment, the first actuating element 1042 and the second actuating element 1044 are disposed around the inner surface 1014, although other embodiments as described above with respect to system 900 are suitable. The first actuating element 1042 includes a proximal end segment 1042a and a distal end segment 1042b extending from a portion of the first actuating element 1042 wrapped around the lumen 1030. The second working element 1044 includes a proximal end 1044a and a distal end 1044b that extend from a portion of the second working element 1044 that is wrapped around the lumen 1030. The proximal end segments 1042a, 1044a and the distal end segments 1042b, 1044b can be secured to various structures (not shown) of the system 1000.

[0076] In some embodiments, the first and second actuating elements 1042, 1044 can be constructed from a shape memory material and can operate in a manner substantially similar to that described above with respect to the system 900. In other embodiments, the system 1000 can include an additional actuator (e.g., a motor (not shown), such as an electromagnetic motor, a mechanical motor, a MEMS motor, a piezoelectric-based motor, etc.) configured to selectively adjust the first actuating element 1042 and the second actuating element 1044. For example, the actuator can adjust the first actuating element 1042 by tightening the first actuating element 1042 about the inner surface 1014 by retracting the proximal end segment 1042a and / or the distal end segment 1042b of the first actuating element 1042. Tightening the first actuating element 1042 about the inner surface reduces the diameter of the lumen 1030. For example, with reference to FIG. 10A, the first actuating element 1042 includes a first configuration in which the adjustable lumen 1030 has a first diameter D1. To reduce the diameter of the lumen 1030, the actuator selectively tightens the first actuating element 1042, narrowing the diameter of the spiral formed by the first actuating element 1042 and squeezing the inner surface 1014. As a result, the lumen 1030 transitions to a second configuration having a second diameter D2 smaller than the first diameter D1, as shown in FIG. 10B. As the first actuating element 1042 extends from the proximal end 1014a to the distal end 1014b of the inner surface 1014, the lumen 1030 narrows along a substantial length of the system 1000. The first actuating element 1042 can be configured to retain its shape after actuation, thereby retaining the second diameter D2 until the actuator drives the system 1000 to a third configuration (not shown).

[0077] Actuating the second actuating element 1044 can have the opposite effect of actuating the first actuating element 1042. For example, actuating the second actuating element 1044 can expand the diameter of the lumen 1030 by the actuator and / or by its shape memory properties. More specifically, actuating the second actuating element 1044 can expand the inner surface 1014 radially outward by the second actuating element 1044 relaxing around the inner surface. This expands the diameter of the lumen 1030. The second actuating element 1044 can be configured to retain its shape after actuation, thereby retaining a desired diameter until the actuator is further activated. Thus, actuating the first actuating element 1042 can reduce the diameter of the lumen 1030, and actuating the second actuating element 1044 can expand the diameter of the lumen 1030. By having the opposite effect, a user can selectively adjust either the first actuating element 1042 or the second actuating element 1044 to achieve a desired lumen diameter.

[0078] In some embodiments, the first actuating element 1042 can be individually tightened and / or loosened by an actuator and / or a shape memory effect, and the second actuating element 1044 can be individually tightened and / or loosened by an actuator and / or a shape memory effect. In such embodiments, a single actuating element (e.g., the first actuating element 1042) can be sufficient to both expand and contract the diameter of the lumen 1030. However, additional actuating elements can still be included to further increase the control and maneuverability of the system 1000. Thus, some embodiments of the system 1000 include 1, 2, 3, 4, 5, 6, 7, and / or 8 or more actuating elements.

[0079] FIG. 11 is a cross-sectional, partial schematic view of an additional embodiment of an adjustable inter-atrial system 1100 ("system 1100") configured in accordance with selected embodiments of the present technology. System 1100 can include certain features that are generally similar to systems 900 and 1000 described with respect to FIGS. 9-10B. For example, system 1100 can include a shunt element 1110 having an outer surface 1112 and an inner surface 1114, a proximal (e.g., RA) surface 1116a and a distal (e.g., LA) surface 1116b. When system 1100 is implanted within a patient, outer surface 1112 (which can also be referred to as a "frame") can engage native cardiac tissue (e.g., septal wall S). Inner surface 1114 can include a membrane that at least partially defines a lumen 1130 configured to fluidly couple the LA and RA of the heart. Shunt element 1110 can have a generally toroidal shape. The shunt element 1110 can be hollow to define a chamber 1150. The system 1100 can also include an anchor element 1120 configured to secure the system 1100 in place by engaging native cardiac tissue (e.g., the septal wall S).

[0080] The system 1100 can include multiple actuating elements 1142. For example, the system can include a first actuating element 1142a, a second actuating element 1142b, a third actuating element 1142c, a fourth actuating element 1142d, a fifth actuating element 1142e, a sixth actuating element 1142f, and a seventh actuating element 1142g. Other embodiments can include additional or fewer actuating elements 1142. The actuating elements 1142 wrap around the lumen 1130 (e.g., within a membrane that defines the inner surface 1114) and are secured to the shunt element 1110. In some embodiments, an individual actuating element (e.g., the first actuating element 1142a) wraps around the lumen once. In other embodiments, an individual actuating element (e.g., the first actuating element 1142a) wraps around the lumen more than once. For example, each of the individual working elements can be wrapped around both the LA and RA sides of the lumen 1130 such that the diameter of the lumen 1130 is adjusted along a substantial length of the lumen 1130. As described above with respect to FIG. 9, the working elements 1142 can be housed within one or more channels 1146.

[0081] Each of the actuating elements 1142a-g can be individually actuated. More specifically, each of the actuating elements 1142a-g can be individually actuated to transition from a passive configuration to an active configuration. An individual actuating element (e.g., actuating element 1142a) does not dictate the diameter of the lumen 1130 when in the passive configuration. An individual actuating element (e.g., actuating element 1142a) adjusts the diameter of the lumen 1130 to a corresponding predetermined diameter when actuated to transition to the active configuration. Thus, each of the actuating elements 1142a-g can be configured to selectively adjust the diameter of the lumen 1130 to a specific predetermined diameter. For example, actuation of actuating element 1142a can adjust the diameter of lumen 1130 to about 12 mm, actuation of actuating element 1142b can adjust the diameter of lumen 1130 to about 5 mm, actuation of actuating element 1142c can adjust the diameter of lumen 1130 to about 6 mm, actuation of actuating element 1142d can adjust the diameter of lumen 1130 to about 7 mm, actuation of actuating element 1145e can adjust the diameter of lumen 1130 to about 8 mm, actuation of actuating element 1145f can adjust the diameter of lumen 1130 to about 9 mm, and actuation of actuating element 1145g can adjust the diameter of lumen 1130 to about 10 mm. Thus, a particular actuating element can be targeted to adjust the lumen 1130 to a desired diameter. Following actuation, the individual working elements can be configured to remain in their active configuration, thereby retaining the diameter of the corresponding lumen until another individual working element is actuated.

[0082] In some embodiments, the actuating element 1142 can be constructed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). As such, the actuating element 1142 can be transitionable between a first material state (e.g., martensitic state, R-phase, etc.) and a second material state (e.g., shape memory state, austenitic state, etc.). In the first state, the actuating element 1142 can be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the actuating element 1142 can have a preference for a particular manufacturing geometry (e.g., shape, length, and / or dimensions). The actuating element 1142 can be transitioned between the first state and the second state by providing energy to the actuating element 1142 to heat (e.g., resistively heat) the actuating element 1142 above a transition temperature. In some embodiments, the first material state corresponds to the passive configuration described above, and the second material state corresponds to the active configuration described above. Thus, in some embodiments, the diameter of the lumen 1130 can be adjusted by heating the individual working elements corresponding to the desired lumen diameter above their transition temperature, thereby transitioning the working elements from a passive configuration to an active configuration.

[0083] 12A and 12B show an actuation assembly 1220, which includes a generally circular actuation element and is configured in accordance with selected embodiments of the present technology. More specifically, FIG. 12A is an isometric view of the actuation assembly 1220, and FIG. 12B is a cross-sectional front view of the actuation assembly 1220 (in which the blood flow axis is horizontal). In some embodiments, the actuation assembly 1220 includes multiple actuation elements 1202-1204 disposed within a sleeve or membrane 1201. In some embodiments, the membrane 1201 can be insulating, e.g., thermally insulating and / or electrically insulating. In embodiments, at least a portion of the membrane 1201 is constructed from a compliant material (e.g., PTFE, ePTFE, silicone, urethane, nylon, etc.) and / or a non-compliant material (e.g., annealed stainless steel, cobalt chrome). The actuation elements 1202-1204 can be constructed from a shape memory material (e.g., Nitinol wire or tube). Each shape memory actuating element may be shaped to have a different geometric configuration. For example, the first actuating element 1202 may have a generally sinusoidal flat pattern and may be constructed to assume a generally circular geometric configuration having a first diameter D1 when wrapped about a central axis. The second actuating element 1203 may have a similar sinusoidal flat pattern and may be constructed to assume a second circular geometric configuration having a second diameter D2 when wrapped about a central axis. The third actuating element 1204 may have a similar sinusoidal flat pattern and may be constructed to assume a third circular geometric configuration having a third diameter D3 when wrapped about a central axis. In a similar manner, any number of additional actuating elements may be included. In further embodiments, the individual actuating elements may have different shapes, sizes, and / or geometric configurations.

[0084] In some embodiments, the actuating elements 1202-1204 are mechanically coupled. In some embodiments, the actuating elements 1202-1204 are thermoelastically manipulated (e.g., deformed) at least partially away from their original geometric configuration (e.g., manufactured geometry) before being mechanically coupled. In some embodiments, the actuating elements 1202-1204 are coupled in a manner such that they are continuously nested (e.g., aligning peaks and valleys of a sinusoidal pattern). The actuating elements 1202-1204 may be coupled using sutures, adhesives / glues, rivets / crimps, welding, etc., and / or may be partially coupled using a mechanical constraint / force applied by the membrane 1201. In some embodiments, the actuating assembly 1220 may include an insulating element 1205 that can have a similar shape, pattern, and / or geometric configuration as one or more of the actuating elements 1202-1204. In some embodiments, the insulating element 1205 is nested in series between the actuating elements 1202-1204. Additionally or alternatively, the insulating element 1205 can be located at the ends of the stack of composite elements (i.e., at the front and rear ends of the stack of consecutive nested elements, as shown in FIGS. 12A and 12B). The insulating element 1205 may provide electrical and / or thermal insulation, or other types of insulation. The insulating element 1205 may be constructed of materials such as low density polymers, PTFE, ePTFE, polyurethanes, silicones, silica, graphene, cellulose, ceramic, or other materials. In some embodiments, the insulating element 1205 is configured as a coating on one or more of the actuating elements 1202-1204 and not as a separate component. When the elements 1202-1205 are joined, the composite nested structure 1210 has an equilibrium composite geometry, e.g., a composite diameter D C The shape may be cylindrical having a

[0085] To adjust a geometric characteristic (e.g., shape, diameter, etc.) of the actuated assembly 1220, energy is applied to one or more of the actuating elements 1202-1204 to raise the temperature of the element(s) above a phase transition temperature of the material (e.g., above an R-phase start, austenite start, R-phase finish, or austenite finish temperature). The actuated element(s) undergoes thermoelastic recovery and as a result changes shape and / or size toward its original geometric configuration (e.g., its manufactured geometry). The remaining elements in the composite structure (which are not directly energized and therefore do not receive substantial heat) remain relatively malleable and therefore deform in a manner complementary to the movement of the actuated element(s) (e.g., in response to a force applied by the actuated elements to which they are attached). By selectively energizing the various actuating elements 1202-1204, or various combinations of actuating elements, the actuating assembly 1220 may change its geometric configuration (e.g., change shape, expand in cross-sectional area, or contract in cross-sectional area) in a manner that affects the flow of fluid therethrough. In an embodiment, the actuating assembly 1220 may function as the lumen of an inter-atrial shunt system. In other embodiments, the actuating assembly 1220 may be integrated with or interfaced with the lumen of the inter-atrial shunt system (e.g., the membrane 1201 may be disposed around a membrane of the shunt system that defines the shunt lumen).

[0086] In some embodiments, the plurality of actuator elements may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more individual actuating elements. In some embodiments, the possible granularity of the geometric change of the actuating assembly 1220 may be increased by increasing the number of actuating elements. In some embodiments, the geometric change of the actuating assembly 1220 may be achieved by partially transitioning a selected actuating element from an initial state to a second state that is between the initial state and the original geometric configuration of the element. For example, a pulse of energy may be delivered to heat the selected actuating element to a temperature between the austenite start temperature and the austenite finish temperature of the material (or alternatively, between the R-phase start temperature and the R-phase finish temperature). Alternatively, or in addition, a pulse of energy may be delivered to heat only a portion of the actuating element, while leaving the remaining portion of the actuating element at a temperature that does not induce thermoelastic recovery. This may be achieved, for example, by heating one or more attachments of the element (e.g., locally heating the element) instead of directly heating the element (e.g., heating the element globally).

[0087] 13A-13D illustrate various actuating assemblies integrated into an inter-atrial shunt system configured in accordance with selected embodiments of the present technology. For example, FIG. 13A illustrates a cross-sectional side view of an inter-atrial shunt assembly 1300. The shunt assembly 1300 includes a lumen 1301 through which a fluid (e.g., blood) can flow. Some embodiments of the shunt assembly 1300 also include anchor elements 1302 and 1304. The embodiments may also include a flow control element or actuating assembly 1303 that operates to control the flow rate of the fluid through the lumen 1301. In some embodiments, the anchor elements 1302 and 1304 are constructed from a superelastic material, such as Nitinol, that is manufactured to have an austenite start and / or finish temperature that is similar to or lower than body temperature. Additional components, such as sensors, energy storage components, electrical components, and data transmission components, may also be included in the shunt assembly 1300, but are not shown in FIGS. 13A-13D for clarity.

[0088] 13B-13D are enlarged cross-sectional views of various exemplary embodiments of an actuating assembly 1303 integrated into a shunt assembly 1300. In embodiments, the actuating assembly can include at least two coupled actuating elements (e.g., two shape-memory actuating elements). For example, in the example shown in FIG. 13B, the actuating assembly includes concentric nested actuating elements 1320 and 1321 (e.g., nested stents) in a manner similar to the embodiment shown in FIGS. 4A-4C. In a second example shown in FIG. 13C, the actuating assembly includes interlocking actuating elements 1330 and 1331 in a manner similar to the embodiment shown in FIGS. 5A-7. In a third example shown in FIG. 13D, the actuating assembly includes elongated wire-like actuating elements (e.g., rings) 1351-1354 in a manner similar to the embodiment shown in FIGS. 12A-12B. In some embodiments, the actuating assembly 1303 is integrated with (e.g., covered by, wrapped inside, surrounded by, or otherwise attached to) a material or membrane layer to create a lumen through which blood can flow. In embodiments, the membrane layer material is comprised of ePTFE, nylon, urethane, or another suitable material known to one of skill in the art. In some embodiments, the actuating assembly 1303 functions as the lumen of the shunt assembly 1300, with or without an integrated layer of material. In other embodiments, the actuating assembly 1303 does not itself constitute a lumen, but interfaces with and directly or indirectly affects the geometry of the lumen of the shunt assembly 1300.

[0089] The present technology also provides inter-atrial shunt systems that include an actuating element that does not directly interface with the shunt lumen. For example, unlike the embodiments described with respect to Figures 3-13D in which the actuating assembly defines, is integrated into, and / or otherwise directly acts on the shunt lumen, the present technology further provides embodiments in which the actuating element is spaced apart from the lumen and does not directly manipulate the lumen.

[0090] For example, Figures 14A-15C illustrate an adjustable inter-atrial shunt system 1400 ("system 1400") configured in accordance with selected embodiments of the present technology. System 1400 includes a shunt element 1401 (e.g., a generally tubular element) having a first end flow aperture 1402 and a second end flow aperture 1404. The shunt element includes a lumen 1405 extending between the first end flow aperture 1402 and the second end flow aperture 1404. When positioned across the septal wall (e.g., as shown in Figure 14B), the first end flow aperture 1402 can be in fluid communication with the RA and the second end flow aperture 1404 can be in fluid communication with the LA. Thus, lumen 1405 can fluidly connect the LA and the RA.

[0091] The shunt element 1401 can include a frame 1410 having an outer surface configured to engage natural tissue, such as a septal wall S. In some embodiments, the frame 1410 can define a chamber 1414 that can contain a gel, fluid, foam, gas, or other object that is compressible and / or displaceable. For example, in some embodiments, the object can compress and / or expand in response to a shape change in the lumen 1405, described in more detail below. In other embodiments, the object can displace and / or return to its original position in response to a shape change in the lumen 1405. The shunt element 1401 further includes an RA anchor 1424 and an LA anchor 1426 configured to secure the device to the septal wall when implanted in a patient.

[0092] The shunt element 1401 can further include a membrane 1406 that at least partially defines the lumen 1405. The membrane 1406 can define a portion of the chamber 1414 or can be coupled to a portion of the frame 1410 that defines the chamber 1414. The membrane 1406 can be constructed of any semi-flexible and biocompatible material, such as PTFE, ePTFE, silicone, nylon, polyethylene terephthalate (PET), polyether block amide (pebax), polyurethane, blends or combinations of these materials, or other suitable materials. In some embodiments, a plurality of spindles 1408 are disposed within or otherwise coupled to the membrane 1406. The spindles 1408 can extend at least partially between the first end flow aperture 1402 and the second end flow aperture 1404 and define the shape of the lumen 1405. In some embodiments, as described in more detail below, the spindle 1408 can be bendable and can be configured to adjust the diameter of the lumen 1405, thereby controlling the amount of blood flowing through the lumen 1405. In some embodiments, the spindle 1408 can be a Nitinol spindle and encased in a thin film polymer, such as ePTFE. In some embodiments, the spindle 1408 is hollow and thin to facilitate bending.

[0093] The system 1400 can further include a first end element 1416 adjacent the first end flow aperture 1402 and a second end element 1418 adjacent the second end flow aperture 1404. The first end element 1416 can be made generally circular or elliptical in shape to avoid blocking blood flow through the lumen 1405. The spindle 1408 can extend between and be coupled to the first end element 1416 and the second end element 1418. The system 1400 can further include an anchor element 1420 positioned adjacent the first end element 1416. As one skilled in the art will appreciate from the disclosure herein, the anchor element 1420 can be positioned adjacent the second end element 1418 and operate in a substantially similar manner. Thus, although the following description describes a system 1400 in which the anchor element 1420 is positioned adjacent to the first end element 1416, the present technology also includes a “mirror image” embodiment in which the anchor element 1420 is positioned adjacent to the second end element 1418.

[0094] In the illustrated embodiment, the anchor element 1420 and the second end element 1418 can be secured to a portion of the system 1400 that is affixed to the septal wall (e.g., the outer surface 1412) and / or can be secured directly to the septal wall. As described below, securing the anchor element 1420 and the second end element 1418 to the system 1400 or the septal wall prevents the anchor element 1420 and the second end element 1418 from moving during adjustment of the lumen diameter. The anchor element 1420 can be coupled to the first end element 1416 via one or more actuating elements 1422. The actuating elements 1422 can be springs, coils, or other elements configured to adjust the distance between the anchor element 1420 and the first end element 1416.

[0095] The first end element 1416 is movable relative to the anchor element 1420. For example, the first end element 1416 can be moved toward the anchor element 1420 to bend the spindles 1408 inward (e.g., toward the central longitudinal axis of the lumen 1405) and reduce the inner diameter of the lumen (e.g., from the configuration shown in FIGS. 14A-14C to the configuration shown in FIGS. 15A-15C). In some embodiments, for example, the spindles 1408 can be bent inward until they touch each other, thereby closing the lumen 1405 and generally blocking any flow through the lumen 1405. However, in other embodiments, the spindles 1408 cannot be bent inward enough to completely close the lumen 1405, so that the lumen remains partially open at all times. Additionally, the first end element 1416 can be moved away from the anchor element 1420 to straighten and / or bend the spindle 1408 outward (e.g., away from the central longitudinal axis of the lumen 1405) thereby expanding the inner diameter of the lumen 1405 (e.g., moving from the configuration shown in FIGS. 15A-15C to the configuration shown in FIGS. 14A-14C). As one of ordinary skill in the art will appreciate from the disclosure herein, the spindle 1408 can be bent to any number of positions to define any number of central inner diameters, not just those explicitly shown in FIGS. 14A-15C. In some embodiments, the length of the lumen 1405 and / or the shunt element 1401 can also change as the inner diameter of the lumen 1405 changes. For example, as the central inner diameter of the lumen 1405 decreases, the length of the lumen 1405 can also decrease. Similarly, as the central inner diameter of the lumen 1405 increases, the length of the lumen 1405 can also increase. However, even in embodiments in which the length of the shunt element 1401 varies, the outer diameter of the shunt element 1401 generally remains constant.

[0096] Various embodiments of the system 1400 provide different mechanisms for adjusting the distance between the anchor element 1420 and the first end element 1416. For example, in some embodiments, the actuating element 1422 can be composed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the actuating element 1422 can be transitionable between a first material state (e.g., a martensitic state, R-phase, etc.) and a second material state (e.g., a shape memory state, an austenitic state, etc.). In the first state, the actuating element 1422 can be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the actuating element 1422 can have a preference for a particular manufacturing geometry (e.g., shape, length, and / or dimensions). The actuating element 1422 can be transitioned between the first state and the second state by providing energy to the actuating element 1422 to heat (e.g., resistively heat) the actuating element 1422 above a transition temperature.

[0097] The actuating element 1422 can be used to adjust the diameter of the lumen 1405 by driving the movement of the first end element 1416 toward or away from the anchor element 1420. For example, as shown in FIGS. 14A-14C, the actuating elements can have a first neutral configuration in which they are lengthened relative to their manufactured geometry. Thus, heating the actuating elements 1422 above their transition temperature causes the actuating elements to compress toward their manufactured geometry. This draws the first end element 1416 toward the anchor element 1420, bending the spindle 1408 toward the central longitudinal axis of the lumen 1405 and reducing the diameter of the lumen (e.g., at the "pinch point" of an hourglass shape), as previously described. For example, FIGS. 15A-15C show the system 1400 in a second configuration after the actuating element 1422 is actuated to reduce the flow rate through the lumen 1405.

[0098] In some embodiments, the actuating element 1422 can operate without relying on shape memory properties. For example, in other embodiments, the actuating element 1422 is a spring having a first tension (e.g., a spring constant). The first tension can be adjusted to a second tension that dictates how tightly the first end element 1416 is retracted toward the anchor element 1420. For example, as the spring tension decreases, the distance between the anchor element 1420 and the first end element 1416 increases, thereby increasing the inner diameter of the lumen 1405. As the spring tension increases, the distance between the anchor element 1420 and the first end element 1416 decreases, thereby decreasing the inner diameter of the lumen 1405. In some embodiments, the spring tension can be adjusted by a magnet external to the patient. In other embodiments, the spring tension can be adjusted mechanically using an adjustment tool delivered through the catheter.

[0099] In another embodiment, the actuation element 1422 is a coil. Upon application of energy to the coil, the length of the coil can be adjusted. For example, upon application of radio frequency ("RF") energy, the length of the coil can be selectively adjusted to (a) adjust the distance between the anchor element 1420 and the first end element 1416, and (b) adjust the inner diameter of the lumen 1405. In some embodiments, the RF energy can be applied external to the patient to minimize the invasiveness of the adjustment procedure. In some embodiments, the RF energy is delivered at a low frequency to reduce signal attenuation and / or reduce tissue heating. Low frequency signals include signals having frequencies between about 20 kHz and 300 kHz. However, one skilled in the art will appreciate that other frequencies, such as less than 20 kHz or greater than 300 kHz, can be used in certain embodiments of the present technology. In some embodiments, the received RF energy can have a power of about 10-30 watts. However, due to scattering attenuation, the device may receive less power than it transmits. Thus, the device can be configured to operate at less power than it transmits, such as 1 watt.

[0100] In another embodiment, the system 1400 can include a mechanical adjustment element (e.g., a screw located on the first end element 1416 or the anchor element 1420). In such an embodiment, the system 1400 can be adjusted using an adjustment tool delivered to the system 1400 via a catheter. In another embodiment, the system 1400 can be adjusted using a balloon or other expandable element. For example, a balloon can be delivered to the lumen via a catheter. When the balloon is inflated, a force is applied that causes the spindle 1408 to bend outwardly, away from the central longitudinal axis of the lumen 1405, thereby expanding the inner diameter of the lumen 1405. The spindle 1408 can include a relatively malleable material such that following deflation and removal of the balloon, the lumen 1405 maintains a set inner diameter.

[0101] 16A-16D illustrate one embodiment of an adjustable inter-atrial system 1600 configured in accordance with selected embodiments of the present technology. The system 1600 includes a frame 1610 and a membrane 1606 positioned within the frame 1610. The frame 1610 can be constructed from a superelastic material (e.g., Nitinol, which has a phase transition temperature lower than body temperature). The membrane 1606 can be any semi-flexible and biocompatible material that forms a lumen 1605. A plurality of spindles 1608 can be embedded within or otherwise coupled to the membrane 1606 to provide structural integrity to the lumen 1605. The lumen 1605 extends between a first end flow aperture 1602 and a second end flow aperture 1604. Thus, when positioned across the septal wall of the heart, the first end flow aperture 1602 can be in fluid communication with the RA and the second end flow aperture 1604 can be in fluid communication with the LA, such that the lumen 1605 fluidly connects the LA and the RA. The system 1600 can also include an RA anchor 1624 and an LA anchor 1625 (e.g., extending from the frame 1610) that secure the system 1600 in place when implanted.

[0102] The system includes an actuation assembly 1620 extending from the frame 1610. The actuation assembly can include one or more rails 1628 and one or more actuation elements 1622. The membrane 1606 can be slidably coupled to one or more rails 1628, 1724 such that the first end flow aperture 1602 can move along the rails in a direction parallel to the longitudinal axis of the lumen 1605. The one or more actuation elements 1622 can be comprised of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the actuation elements 1622 can be transitionable between a first material state (e.g., a martensitic state, R-phase, etc.) and a second material state (e.g., a shape memory state, an austenitic state, etc.). In the first state, the actuation elements 1622 can be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the actuating element 1622 may have a preference for a particular manufacturing geometry (e.g., shape, length, and / or dimensions). The actuating element 1622 can be transitioned between the first state and the second state by providing energy to the actuating element 1622 to heat (e.g., resistively heat) the actuating element 1622 above a transition temperature.

[0103] In the illustrated embodiment, the actuating assembly 1620 includes a first actuating element 1622a and a second actuating element 1622b. The first actuating element 1622a extends from a proximal end 1620a of the actuating assembly 1620 and is coupled to a portion of the lumen 1605 at or adjacent to the first end flow aperture 1602. The second actuating element 1622b extends from a distal end 1620b of the actuating assembly 1620 and is coupled to a portion of the lumen 1605 at or adjacent to the first end flow aperture 1602. At least one of the first actuating element 1622a and the second actuating element 1622b is deformed relative to its manufactured geometry. For example, FIG. 16B shows that both the first actuating element 1622a and the second actuating element 1622b are deformed (e.g., lengthened) relative to their manufactured geometry. Heating the first actuating element 1622a above its transition temperature causes the first actuating element 1622a to transition from a first material state to a second material state and move toward its more compressed manufactured geometry shown in FIG. 16C. This causes the length of the lumen 1605 to decrease as the first inlet aperture 1602 is pulled toward the proximal end 1620a of the actuating assembly 1620, and causes the spindle 1608 (and thus the membrane 1606) to bend inwardly toward the central longitudinal axis of the lumen 1605, thereby decreasing the diameter of the lumen 1605. Conversely, heating the second actuating element 1622b above its transition temperature causes the second actuating element 1622b to transition from a first material state to a second material state and move toward its more compressed manufactured geometry shown in FIG. 16D. This causes the length of the lumen 1605 to expand as the first inlet aperture 1602 is pulled towards the distal end 1620b of the actuation assembly 1620, and causes the spindle 1608 (and thus the membrane 1606) to bend outward, away from the central longitudinal axis of the lumen 1605, thereby expanding the diameter of the lumen 1605. Thus, the first and second actuation elements 1622a, 1622b can be selectively heated to expand or contract the diameter of the lumen 1605 to regulate the flow of fluid therethrough.

[0104] FIG. 17A is an isometric, partial cutaway view of an adjustable inter-atrial shunt system 1700 ("system 1700") configured in accordance with an embodiment of the present technology. System 1700 includes a plate 1702, a shunt element 1710, and an actuating assembly 1720. The shunt element 1710 and the actuating assembly 1720 can be coupled to the plate 1702. To secure the system 1700 in a desired position, the plate 1702 can be secured to the septal wall or other anatomical structure when the system 1700 is implanted in a patient. The plate 1702 can have any number of shapes and sizes that allow the system 1700 to be delivered across and secured to the septal wall. For example, the plate 1702 can be smaller than illustrated to fit the approximate size profile of the shunt element 1710 and / or the actuating assembly 1720. In some embodiments, some and / or all of the actuating assembly 1720 can be spaced from the plate 1702 by a spacer element (not shown). For example, the working assembly 1720 can be spaced from the plate 1702 by about 1 mm or more. In such embodiments, the plate 1702 can be secured to the septal wall such that the working assembly 1720 extends at least partially into a heart chamber (e.g., the RA). In other embodiments, the plate 1702 can be omitted and the shunt element 1710 and / or working assembly 1720 can be secured to the septal wall, either directly or with other suitable anchoring mechanisms.

[0105] Plate 1702 is configured to reside on a first side (e.g., RA side) of the septal wall. In some embodiments, system 1700 may include an anchor (e.g., additional) configured to secure system 1700 to the septal wall. For example, FIGS. 17B and 17C show an embodiment of system 1700 including an optional anchoring mechanism. FIG. 17B illustrates system 1700 from the RA, and FIG. 17C illustrates system 1700 from the LA. As shown in FIG. 17B, plate 1702 can optionally include anchor port 1751. Anchor port 1751 can be configured to receive and secure anchor 1752 (e.g., a flared anchor) (FIG. 17C). 17C, the system 1700 is secured in place by the plate 1702 on the RA side of the septal wall and the flared anchor 1752 on the LA side of the septal wall, as the flared anchor 1752 can engage the septal wall. When implanted across the septal wall, the working assembly 1720 can be positioned on the RA or LA side of the septal wall. In some embodiments, the system 1700 can be collapsed into a delivery catheter having an outer diameter of about 30 Fr or less, or about 20 Fr or less, to facilitate delivery of the system 1700 to the heart.

[0106] Returning to FIG. 17A , the shunt element 1710 includes a lumen 1712 extending therethrough. In the illustrated embodiment, the shunt element 1710 has a generally tubular or cylindrical shape defining the lumen 1712. However, in other embodiments, the shunt element 1710 can have other suitable shapes. The shunt element 1710 can include at least a partially deformable and / or flexible material, which can allow the shape and / or size of the shunt element 1710 to change, as described in more detail below. When the system 1700 is implanted adjacent the septal wall, the shunt element 1710 fluidly couples the patient's LA to the patient's RA via the lumen 1712.

[0107] The actuation assembly 1720 includes a rim 1725 having a vertebrae 1725a with first and second anchor elements 1721a, 1721b extending generally perpendicularly from opposite ends of the vertebrae 1725a. The second anchor element 1721b can extend generally toward the shunt element 1710 to define a shunt element anchor 1726. In some embodiments, a portion of the shunt element anchor 1726 can engage an outer surface portion of the shunt element 1710. Part or all of the rim 1725 can be secured to the plate 1702 and / or the septal wall. Thus, the rim 1725 is configured to remain stationary when the actuation assembly 1720 is actuated to adjust the size and / or shape of the lumen 1712, as described in more detail below.

[0108] The actuation assembly 1720 further includes a movable element 1723, a first actuation element 1722a extending between the first anchor element 1721a and the movable element 1723, and a second actuation element 1722b extending between the second anchor element 1721b and the movable element 1723. In the illustrated embodiment, the first actuation element 1722a is in a compressed state and the second actuation element 1722b is in a partially expanded state. However, as described in more detail below with respect to FIGS. 18A-18C, the first actuation element 1722a and the second actuation element 1722b can expand and compress to change the configuration of the actuation assembly 1720. The movable element 1723 is generally between the first actuation element 1722a and the second actuation element 1722b. A movable arm 1724 extends from the movable element 1723 and can be generally parallel to the anchor 1726 of the shunt element. The movable arm 1724 extends generally adjacent to the shunt element 1710, but generally over an opposite side of the shunt element anchor 1726. Thus, the shunt element 1710 is generally positioned between the movable arm 1724 and the shunt element anchor 1726. The movable arm 1724 can engage the shunt element 1710 to change the size and / or shape of the lumen 1712, as described in more detail below.

[0109] In the illustrated embodiment, the actuating assembly 1720 has a relatively flat profile. For example, the actuating assembly 1720 may extend outwardly from the plate 1702 and / or the septal wall (when implanted) by less than about 10 mm (e.g., less than about 5 mm or less than about 2 mm). Thus, the actuating assembly 1720 may extend less than about 10 mm (e.g., less than about 5 mm or less than about 2 mm) into a heart chamber (e.g., RA) when implanted in a patient. Without wishing to be limited by theory, the relatively flat profile of the actuating assembly 1720 is expected to reduce the risk of thromboembolic events. Additionally, in some embodiments, the actuating assembly 1720 may also be positioned within a bladder or other membrane (not shown) such that the actuating assembly 1720 is fluidly isolated from the surrounding environment.

[0110] Various aspects of the actuation assembly 1720 can include shape memory material(s) and / or superelastic material(s) configured to transition at least partially from a martensite phase to an austenite phase upon application of energy. For example, at least the first actuation element 1722a and the second actuation element 1722b can be comprised of a shape memory alloy, such as Nitinol. Thus, the first actuation element 1722a and the second actuation element 1722b can undergo an increase in temperature above a transition temperature in the material and change shape (e.g., expand and / or compress its length, width, etc.) in response to exposure to energy, such as light and / or electric current. In such embodiments, the actuation assembly 1720 can be selectively actuated by directly or indirectly applying energy to the first actuation element 1722a and / or the second actuation element 1722b. In some embodiments, energy can be applied to individual bending regions of the spring elements (e.g., bending regions 1832a-d, FIG. 18B). As described in further detail below, targeting individual bend regions 1832a-d is expected to provide further control over adjustment of system 1700 by allowing a user to selectively dose treatment. In some embodiments, other aspects of actuating assembly 1720 may also include Nitinol or other suitable shape memory material(s) and / or superelastic material(s). For example, rim 1725 may be constructed from Nitinol, but configured to exhibit superelastic properties at body temperature. Thus, in some embodiments, actuating assembly 1720 may be laser cut from a single sheet of Nitinol or other suitable material.

[0111] FIG. 18A is a top view of the system 1700 in the configuration shown in FIG. 17A (i.e., the first configuration). In the illustrated state, the first actuating element 1722a is generally compressed and the second actuating element 1722b is at least partially expanded. Thus, the first actuating element 1722a has a length L1 and the second actuating element 1722b has a length L2 that is greater than the length L1. As described in more detail below with respect to FIGS. 18B and 18C, the lengths L1 and L2 can be varied by selectively expanding or compressing the first actuating element 1722a and / or the second actuating element 1722b. As in the illustrated configuration of FIG. 18A, when the second actuating element 1722b is at least partially expanded, the movable arm 1724 does not compress the lumen 1712 and the lumen 1712 has a generally circular cross-sectional shape. For example, lumen 1712 has a first diameter D1 (eg, a generally horizontal diameter) that is approximately equal to a second diameter D2 (eg, a generally vertical diameter).

[0112] 18B is a top view of the system 1700 in a second configuration following at least partial actuation of the actuation assembly 1720. In particular, the first actuation element 1722a expands from a compressed state to a partially expanded state in response to the application of energy E. In the illustrated embodiment, the energy E is applied to the second bending region 1732b of the first actuation element 1722a. This causes the first actuation element 1722a to transition from a first material state (e.g., martensite) to a second material state (e.g., austenite) at least in the second bending region 1732b when heated above its transition temperature. Thus, in some embodiments, the individual bending regions can be individually actuated. In other embodiments, more than one individual bending region actuates and / or expands in response to the application of energy E.

[0113] As the first working element 1722a expands, the first working element 1722a pushes the movable element 1723 toward the second anchor element 1721b because the first anchor element 1721a and the second anchor element 1721b are secured to each other via the vertebrae 1725a (e.g., they do not move as the working elements move). As a result, the second working element 1722b is pushed from the partially expanded state toward the compressed state because it remains in a relatively malleable material state. Thus, in the illustrated configuration of FIG. 18B, the length L1 of the first working element 1722a is approximately equal to the length L2 of the second working element 1722b. As the movable element 1723 is pushed toward the second anchor element 1721b, the movable arm 1724 also moves toward the shunt element anchor 1726 and engages the shunt element 1710. Since the shunt element anchor 1726 is also fixed (e.g., does not move as the spring element moves), the lumen 1712 is at least partially deformed (e.g., compressed, squeezed, tightened, etc.) between the movable arm 1724 and the shunt element anchor 1726. Thus, at least one of the size or shape contours of the lumen 1712 changes. In the illustrated embodiment, the lumen 1712 is compressed into a generally elliptical shape such that the first diameter D1 is smaller than the second diameter D2. While not wishing to be limited by theory, varying the shape and / or size of the lumen provides a determinable amount of therapy / shunting that can be tailored specifically to the needs of the patient. In some embodiments, the interaction of the movable arm 1724 with the shunt element 1710 causes the lumen 1712 to deform along the entirety or a majority of the working length of the element (e.g., its length in a direction perpendicular to the anchor 1726). In some variations, interaction of the movable arm 1724 with the shunt element 1710 causes local deformation of the lumen 1712 in a confined area near where the arm and element join at the interface.

[0114] 18C is a top view of the system 1700 in a third configuration following further actuation of the actuation assembly 1720. As energy E continues to be delivered to the first actuation element 1722a (either for a longer period of time or at additional locations), the first actuation element 1722a continues to expand until the second actuation element 1722b is generally in a compressed state (e.g., length L1 is greater than length L2). This causes the movable element 1723 and the movable arm 1724 to move further toward the second anchor element 1721b and the shunt element anchor 1726, respectively, further changing the shape and / or size of the lumen 1712. For example, the shunt element 1710 is further tightened such that the first diameter D1 continues to decrease and the second diameter D2 continues to increase, compared to the configurations shown in FIGS. 18A and 18B. When the desired shape and / or size of the lumen 1712 is achieved, the energy source can be turned off. Because the system 1700 can be constructed at least in part from a shape memory material, the first actuating element 1722a and / or the second actuating element 1722b can be configured to retain their shape upon cessation of energy input. For example, the system 1700 can retain the configuration shown in FIG. 18C until further energy is applied to the first actuating element 1722a and / or the second actuating element 1722b. Thus, once the desired lumen shape and / or size is achieved, the lumen 1712 is configured to retain the selected shape and / or size until further energy is applied.

[0115] In some embodiments, the system 1700 may include a locking mechanism (not shown) to further anchor the actuation assembly 1720 and / or the system 1700 to a desired lumen shape and / or size. In some embodiments, the locking mechanism can be engaged and / or disengaged using (i) the same energy source used to adjust the actuation assembly 1720, (ii) the same energy source operating at different parameter values ​​(e.g., frequency, temperature, etc.), and / or (iii) a different energy source. In some embodiments, the locking mechanism can automatically engage and lock the shunt element 1710 in a given configuration when the actuation assembly 1720 is not adjusted. In such embodiments, actuation of the actuation assembly 1720 can generate sufficient force to disengage the locking mechanism.

[0116] Altering the shape of the lumen 1712 of the shunt element 1710 can have several advantages, including quantifying blood flow rate, flow velocity, and / or other characteristics that are more optimized for the patient's needs. For example, as the shape of the lumen moves from a predominantly circular cross-section (e.g., as in FIG. 18A ) to a predominantly oval cross-section (e.g., as in FIG. 18C ), the circumference of the lumen 1712 can remain constant, but the cross-sectional area decreases, thereby decreasing the flow rate through the lumen 1712. Although described above with reference to three specific configurations, the system 1700 can be transitioned between any number of configurations using the actuation assembly 1720. 18A , energy can be applied to the second actuating element 1722b such that when the second actuating element 1722b is heated above its transition temperature, the second actuating element expands and pushes the movable element 1723 and the movable arm 1724 towards the first anchor element 1721a and away from the shunt element 1710. Thus, the size and shape of the lumen 1712 can be selectively and reversibly manipulated using the actuating assembly 1720.

[0117] When the first actuating element 1722a and the second actuating element 1722b are in a comparable state, the lengths L1 and L2 of the first actuating element 1722a and the second actuating element 1722b, respectively, can be the same or different. For example, the length L1 of the first actuating element 1722a when in a compressed state (FIG. 18A) can be generally the same as the length L2 of the second actuating element 1722b when in a compressed state (FIG. 18C). In other embodiments, the length L1 of the first actuating element 1722a when in a compressed state is not the same as the length L2 of the second actuating element 1722b when in a compressed state. Thus, as one skilled in the art will appreciate from the present disclosure herein, the system 1700 can be manufactured in a variety of sizes and configurations without departing from the scope of the present disclosure.

[0118] In some embodiments, the actuating assembly 1720 can be biased prior to implanting the system 1700 in a patient. For example, the actuating assembly 1720 can be biased toward the configuration shown in FIG. 18A or the configuration shown in FIG. 18C depending on the anticipated needs of the patient. However, if the biased position of the system 1700 is not desired, the actuating assembly 1720 can be actuated (e.g., either before or after implantation) to achieve a desired shape and / or size of the lumen 1712. In some embodiments, when adjusting the system 1700 after implantation, the energy E can be applied from an energy source (e.g., an ultrasonic or electromagnetic energy source) positioned outside the patient's body. Thus, the energy can be "non-invasive." In some embodiments, the energy E can be applied from an energy source positioned adjacent to the shunt, such as an energy source (e.g., a laser) delivered via a catheter. In some embodiments, the shunt can include one or more energy storage components that can be configured to store energy in or adjacent to the system 1700 and selectively release the energy to provide it to the actuation assembly 1720.

[0119] 19A is a top view of an adjustable inter-atrial shunt system 1900 ("system 1900") configured in accordance with an embodiment of the present technology. Certain aspects of system 1900 can be generally similar to system 1700. For example, system 1900 includes an actuation assembly 1920. Similar to actuation assembly 1720 described above, actuation assembly 1920 includes a first actuation element 1922a and a second actuation element 1922b. However, actuation assembly 1920 differs from actuation assembly 1720 in that actuation assembly 1920 includes a first resistor or control wire 1930a that extends along at least a portion of the first actuation element 1922a, and a second resistor or control wire 1930b that extends along at least a portion of the second actuation element 1922b. The first and second control wires 1930a, 1930b can be embedded within or positioned on the surfaces of the first and second actuating elements 1922a, 1922b, respectively. The control wires 1930a-b can be configured to deliver energy to the actuating elements 1922 to heat the actuating elements 1922 above their transition temperatures and induce a phase change (e.g., a transition from a martensite material phase to an austenite material phase). In some examples, using the control wires 1930a-b to deliver energy to the actuating elements 1922 can result in a more uniform distribution of heating along the corresponding actuating elements 1922.

[0120] The first control wire 1930a and the second control wire 1930b can be selectively actuated to provide energy (e.g., heat) to the first actuating element 1922a or the second actuating element 1922b. For example, the system 1900 can include a first actuator 1940a configured to provide energy to the first control wire 1920a and a second actuator 1940b configured to provide energy to the second control wire 1920b. The first actuator 1940a and the second actuator 1940b can be an electronic circuit or other suitable mechanism(s) capable of selectively producing an electric current or other energy. In some embodiments, the first actuator 1940a and the second actuator 1940b can include a coil that produces an electric current in response to magnetic energy. To adjust the shape or size of the lumen 1912, the first actuator 1940a can deliver energy to the first actuating element 1922a via the first control wire 1930a to expand the first actuating element 1922a, as described in detail above with respect to FIGS. 17A-18C. Similarly, the second actuator 1940b can deliver energy via the second control wire 1930b to the second actuating element 1922b, causing the second actuating element 1922b to expand.

[0121] In some embodiments, each actuation element may include multiple independently activatable control wires 1930. Each of the multiple independently activatable control wires 1930 may be configured to deliver energy to a particular bending region within the corresponding spring element. For example, a first control wire may deliver energy to a first bending region 1932a within the second actuation element 1922b, a second control wire may deliver energy to a second bending region 1932b within the second actuation element 1922b, a third control wire may deliver energy to a third bending region 1932c within the second actuation element 1922b, and a fourth control wire may deliver energy to a fourth bending region 1932d within the second actuation element 1922b. Similarly, the multiple independently activatable control wires may be configured to deliver energy to individual bending regions of the first actuation element 1922a. Having individual control wires for individual bending regions is expected to provide greater precision in control over the actuation of the system 1900 by allowing a user to selectively actuate separate portions of the actuation elements.

[0122] Figures 19B - 19D show schematic views of embodiments of the actuating element 1922 (which can be either the first actuating element 1922a or the second actuating element 1922b). As described above, the actuating element 1922 may be composed of a shape memory material constructed in the geometry configuration represented in FIG. 19D and a triangular wave-shaped member having a total length D3 of the protruding elements. At a given temperature (e.g., room temperature), the actuating element 1922 can be relatively malleable (e.g., at least partially in a martensite material state) and can be compressed along the axis, so the triangular wave pattern is characterized by a sharper (more acute) angle, and the total length of the protruding elements changes to D1 as shown in FIG. 19B (where D1 < D3). In an embodiment, the actuating element 1922 includes a plurality of energy exchange points (e.g., electrical connection interface points) 1951 - 1955 that enable selective actuation of the element 1922. In an exemplary operation, an electrical energy source such as the first or second actuator 1940a, b in FIG. 19A is configured to deliver current through a circuit path defined by connection points 1951 and 1953. Thus, resistive heating can preferably occur across the portion of the actuating element 1922 bounded by connection points 1951 and 1953. If the heating is sufficient to drive the material to the phase transition temperature (e.g., above the R-phase start temperature, austenite start temperature, R-phase end temperature, or austenite end temperature), this portion of the actuating element can expand towards its shape-set geometry configuration. The resulting geometry of the element is shown in FIG. 19B, where the total length of the element has increased to D2 (where D1 < D2 < D3). To return the actuating element 1922 to its original geometry configuration (protruding length D3) (or approximately so), electrical energy can be applied across the circuit between connection points 1951 and 1955. Alternatively, energy can be applied to the entire element 1922 (either simultaneously across the entire element or gradually across portions of the element sequentially), and it can be returned to approximately its length D3. Alternatively, energy can be applied only across those elements that have not yet released their thermoelastic energy (e.g., by electrically connecting the circuit between connection points 1953 and 1955).As shown, the addition of localized energy deposition zones can increase the granularity at which geometry changes can be induced in the actuating element. In an alternative embodiment, a second actuating element (e.g., an opposing actuating element) having a relatively compressed shape-set geometry configuration can be coupled to actuating element 1922 such that the composite element can be toggled back and forth between a relatively elongated geometry configuration and a relatively compressed geometry configuration, as previously described. Although described with reference to system 1900, one skilled in the art will understand that the discussion relating to resistively heating a shape memory actuating element can be applied to any of the embodiments described herein.

[0123] 20A-20C illustrate another adjustable inter-atrial shunt system 2000 ("system 2000") configured in accordance with selected embodiments of the present technology. With reference to FIG. 20A, system 2000 includes a first shunt element 2004 with a lumen 2003 on a first (e.g., RA) side of the septal wall S, and a second shunt element 2005 on a second (e.g., LA) side of the septal wall S. In some embodiments, the first shunt element 2004 and the second shunt element 2005 can be a continuous structure that traverses the septal wall S. In other embodiments, the first shunt element 2004 and the second shunt element 2005 can be separate components of the system 2000, but are still fluidly connected. System 2000 also includes an actuating assembly 2020 that is oriented approximately parallel to the first shunt element 2004. In some embodiments, the actuating assembly 2020 can be at least partially spaced from the septal wall (e.g., by a spacer plate 2012).

[0124] The actuation assembly 2020 can include a first shape memory component 2006, a second shape memory component 2007, a shuttle component 2008 that resides between the shape memory components 2006, 2007, and a restrictive band 2009 that is coupled to the shuttle component 2008. As best seen in FIGS. 20B and 20C, the restrictive band 2009 can at least partially wrap around the first shunt element 2004. The shape memory components 2006, 2007 and the shuttle component 2008 can be coupled (either by direct coupling or by additional intermediate connectors) at an interface with a stabilizing component 2013 that is generally parallel to the vertical axis of the diameter of the lumen 2003. The apex and bottom ends of the stabilizing component 2013 can include a linking arm 2010 that interfaces with a proximal side of a spacer plate 2012. In some embodiments, the distal side of the spacer plate 2012 is configured to interface with the septal wall S. The spacer plate 2012 can include an access notch 2011 allowing the restraining band 2009 to rotate approximately 90 degrees out of the plane containing the shuttle component 2008 and the shape memory components 2006 , 2007 and surround the first shunt element 2004 .

[0125] The first shape memory component 2006 and the second shape memory component 2007 can function in much the same manner as the actuating elements described above with respect to FIGS. 16A-19. Thus, the first shape memory component 2006 can be activated with energy to transition the first shape memory component from a relatively contracted martensite state to a relatively expanded austenite state. Similarly, the second shape memory component 2007 can be activated with energy to transition the second shape memory component from a relatively contracted martensite state to a relatively expanded austenite state. Heating the first shape memory component 2006 generally pushes the shuttle component 2008 toward the spacer plate 2012, and heating the second shape memory component 2007 generally pushes the shuttle component 2008 away from the spacer plate 2012. Moving the shuttle component 2008 can adjust the force on the restrictive band 2009 to affect the size of the shunt. For example, FIG. 20B is a front view of the system 2000 in a first state with a relatively high flow rate. 20C is a front view of the system 2000 in a second state, with a relatively low flow rate. The system 2000 can transition between the configurations shown in FIGS. 20B and 20C, among other configurations, following actuation of the actuation assembly 2020 to increase the force on the restraint band 2009.

[0126] FIG. 21A illustrates an adjustable inter-atrial shunt system 2100 ("system 2100") configured in accordance with selected embodiments of the present technology. System 2100 includes an outer frame 2110 and an adjustable inner lumen 2130. Frame 2110 includes a plurality of arms 2112 that define a scaffold for system 2100. Frame 2110 may further include a plurality of right atrial anchors 2122 and a plurality of left atrial anchors 2124, which in some embodiments may extend from the plurality of arms 2112. Right atrial anchors 2122 and left atrial anchors 2124 are configured to engage native heart tissue when system 2100 is implanted in the heart to secure system 2100 in place. Frame 2110 may be encased in an outer membrane 2114 suitable for engaging native heart tissue. For example, outer membrane 2114 may be a biocompatible and / or anti-thrombogenic material such as ePTFE. In some embodiments, the outer membrane 2114 is an elastomeric material that is at least partially stretchable and / or flexible.

[0127] The adjustable inner lumen 2130 includes a proximal end 2132 positionable within the RA of the human heart. The adjustable inner lumen 2130 extends from a longitudinal length of the system 2100 to a distal end (not shown). When the system 2100 is implanted, the distal end of the lumen 2130 is configured to reside within the LA of the heart. Thus, the lumen 2130 fluidly connects the LA and RA of the heart when implanted. The lumen 2130 is defined by a plurality of struts 2134 that extend along the axial length of the lumen 2130. The plurality of struts 2134 are generally parallel to a central axis of the lumen 2130. The struts 2134 may comprise a shape memory and / or superelastic material such as Nitinol, a malleable material such as annealed or unannealed stainless steel, cobalt chrome, or other suitable material. The struts 2134 can be connected to the frame 2110 (e.g., arms 2112) via one or more connecting struts 2140. In addition, the connecting struts 2140 can comprise a shape memory and / or superelastic material such as Nitinol, a malleable material such as annealed or unannealed stainless steel, cobalt chrome, or other suitable material. As described below with reference to Figures 21B-21D, the one or more connecting struts 2140 can be actuated to change the position of the struts 2134 and change the diameter of the lumen 2130.

[0128] The lumen 2130 is further defined by an inner membrane 2133. In some embodiments, the inner membrane 2133 forms a sheath around the struts 2134 (e.g., the struts 2134 can be embedded within the inner membrane 2133). In other embodiments, the struts 2134 can be positioned adjacent to the inner membrane 2133, but not encased in the inner membrane. For example, the struts 2134 can be inside the inner membrane 2133 (e.g., within the lumen 2130) or outside the inner membrane 2133 (e.g., outside the lumen 2130). When the struts 2134 are not encased in the inner membrane 2133, the struts 2134 can be connected to the inner membrane 2133 as they would be otherwise, although in other embodiments, the struts 2134 are not connected to the inner membrane 2133. Regardless of the relative positioning of the struts 2134 and the inner membrane 2133, the inner membrane 2133 may form a single and / or continuous membrane with the outer membrane 2114 of the frame 2110 (in such embodiments, the outer membrane 2114 and the inner membrane 2133 may collectively be referred to as a single or unitary membrane). The volume of space between the outer membrane 2114 and the inner membrane 2133 may form a generally toroidal shaped chamber 2150, as described in more detail below. The inner membrane 2133 may comprise the same material as the outer membrane 2114 of the frame 2110. For example, the inner membrane 2133 may be a biocompatible and / or anti-thrombogenic material, such as ePTFE, and / or an elastomeric material that is at least partially stretchable and / or flexible. For example, in one embodiment, the inner membrane 2133 is ePTFE and forms a sheath around the struts 2134. In some embodiments, the inner membrane 2133 and the outer membrane 2114 can comprise different materials. In some embodiments, the system 2100 includes 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and / or 12 struts 2134.As described in more detail with respect to Figures 21B-21D, the struts 2134 may be malleable and / or include one or more hinges such that the struts can dynamically change shape (e.g., expand, collapse, or otherwise bend) to change the diameter of the inner lumen 2130.

[0129] As described above, the volume between the outer membrane 2114 of the frame 2110 and the inner membrane 2133 of the adjustable inner lumen 2130 defines a generally toroidal shaped chamber 2150. The chamber 2150 can be fluidly isolated from the interior of the lumen 2130 via the inner membrane 2133. The chamber 2150 can also be fluidly isolated from the environment surrounding the system 2100 via the outer membrane 2114. Thus, in some embodiments, the system 2100 is configured to prevent blood from flowing into the chamber 2150. In some embodiments, the chamber 2150 can include a compressible and / or displaceable liquid, gas, and / or gel. Thus, as the diameter of the lumen 2130 is adjusted, the liquid or gas can either compress, expand, and / or displace. The chamber 2150 can also house one or more electronic components (e.g., a battery, a supercapacitor, etc.). In such embodiments, the electronic components can be electrically isolated from other system components.

[0130] 21B-21D are schematic illustrations of the adjustable inner lumen 2130 of the system 2100. FIGS. 22A-22C are schematic illustrations of the operational stages shown in FIGS. 21B-21D, but further show the system 2100 implanted across the septal wall S. Referring to FIG. 21B, the struts 2134 are coupled to the frame 2110 (e.g., the arms 2112 shown in FIG. 21A) via a first connecting strut 2140a at a proximal end (e.g., right atrium) and a second connecting strut 2140b at a distal end (e.g., LA) (collectively referred to as "connecting struts 2140"). As described above, the struts 2134 at least partially define the shape of the lumen 2130. The first connecting strut 2140a can connect the struts 2134 to the frame 2110 at a proximal connection 2136 on the RA side of the system 2100. The second connecting strut 2140b can connect the strut 2134 to the frame 2110 at a distal connection 2138 on the LA side of the system 2100. The transition between the first connecting strut 2140a and the strut 2134 can include a hinge or other bendable feature 2135a (hereinafter referred to as "hinge 2135a"). Similarly, the transition between the strut 2134 and the second connecting strut 2140b can also include a hinge or other bendable feature 2135b (hereinafter referred to as "hinge 2135b"). As described below, the hinge 2135 allows for dynamic adjustment of the diameter of the lumen 2130 by bending and / or folding the strut 2134 relative to the first and second connecting struts 2140.

[0131] 21B, the system 2100 is shown in a first configuration in which the lumen 2130 has a first inner diameter X1. The frame 2110 has a diameter D, and the proximal link 2136 and hinge 2135a are separated by a distance Y1. As the proximal end 2132 of the inner lumen 2130 is moved distally (e.g., toward LA) to reduce the inner diameter of the lumen 2130, the struts 2134 are bent at the hinges 2135a, 2135b. More specifically, in the illustrated embodiment, the angle defined by the first link strut 2140a and strut 2134 at hinge 2135a increases, and the angle defined by the second link strut 2140b and strut 2134 at hinge 2135b decreases. Thus, in various embodiments, the struts 2134 have a fixed length but are movable through a range of positions by the connecting struts 2140 to change the diameter of the lumen 2130. In such embodiments, the lumen 2130 defined by the struts 2134 remains a constant length (e.g., length L1 remains substantially the same) even as the diameter of the lumen 2130 changes.

[0132] FIG. 21C illustrates a second configuration of the system 2100, where the inner lumen 2130 has a second inner diameter X2 that is smaller than the first inner diameter X1. The proximal end 2132 and the hinge 2135a are separated by a distance Y2 that is smaller than the distance Y1. The diameter D of the frame 2110 does not change substantially. FIG. 21C illustrates a third configuration of the system 2100, where the inner lumen 2130 has a third inner diameter X3 that is smaller than the second inner diameter X2. The proximal end 2132 and the hinge 2135a are separated by a distance Y3 that is smaller than the distance Y2. The diameter D of the frame 2110 does not change. As discussed above, the struts 2134 and / or the connecting struts 2140 can include a shape memory material. Thus, once the struts 2134 and connecting struts 2140 have been moved to a desired position, the struts can retain their configuration and the lumen will retain a constant diameter until an active input is received (e.g., via an actuation mechanism, as discussed below).

[0133] In various embodiments, the system 2100 is configured to adjust from a first configuration to a second configuration. In the first configuration, the lumen 2130 has a substantially constant first diameter. In the second configuration, the lumen 2130 has a substantially constant second diameter that is different from the substantially constant first diameter. The lumen may have a substantially constant diameter along all or substantially all of its length. However, in other embodiments, the lumen may have a substantially constant diameter along only a majority of its length. For example, the lumen diameter may be substantially constant along the portion that extends through the septal wall. In another example, the lumen has a substantially constant diameter along its length and includes additional features adjacent the lumen at one or both ends, such as a flared, funnel-shaped, tapered, etc. For example, as described in more detail below, the system 2100 illustrates a lumen 2130 including a funnel-shaped inflow component 2137 configured for fluid communication with the left atrium of the heart (not shown) and a cylindrically-shaped outflow portion 2139 configured for fluid communication with the right atrium of the heart (not shown).

[0134] 21B-21D (and FIGS. 22A-22C) show only three lumen diameters, one skilled in the art will appreciate that the struts 2134 can be actuated through multiple configurations (not shown) resulting in multiple distinct lumen diameters. For example, the lumen can be any diameter between a fully open and a fully closed configuration. Further, in addition to decreasing the diameter of the lumen 2130 as shown, the struts 2134 can be selectively actuated through the connecting struts 2140 to increase the diameter of the lumen 2130. To increase the diameter of the inner lumen 2130, the proximal end 2132 of the inner lumen 2130 moves proximally (e.g., further within the RA) such that the angle defined by the first connecting strut 2140a and strut 2134 at hinge 2135a decreases, and the angle defined by the strut 2134 and the second connecting strut 2140b at hinge 2135b increases. Thus, the system 2100 allows the diameter of the lumen 2130 to be selectively adjusted to control the flow rate of blood through the lumen 2130. The particular diameter of the lumen 2130 can be selected based on the needs of the patient.

[0135] Once implanted within the heart, the system 2100 can be adjusted between the configurations shown in Figures 21B-21D. For example, Figure 22A shows the system 2100 implanted across the septal wall S and in a first configuration (e.g., the configuration shown in Figure 21A above). To reduce blood flow through the lumen 2130, the struts 2134 can be directed radially inward by bending at hinges 2135a, 2135b, as described in detail above, to assume a second configuration shown in Figure 22B (e.g., corresponding to the configuration shown in Figure 21C), and / or a third configuration shown in Figure 22C (e.g., corresponding to the configuration shown in Figure 21D).

[0136] In some embodiments, the system 2100 can be adjusted using an inflatable balloon delivered into a vessel near the system 2100. For example, a balloon (not shown) can be delivered via a catheter and positioned within the lumen 2130. Inflating the balloon can push the struts 2134 radially outward and expand the lumen (e.g., transition from the configuration shown in FIG. 22C to the configuration shown in FIG. 22A). The balloon can also be used to reduce the diameter of the lumen 2130 by pushing the proximal end 2132 distally, such as at the hinge 2135a. For example, FIGS. 23A-23C show deployment of the system 2100. The system 2100 can have a low profile delivery configuration, shown in FIG. 23A. The low profile delivery configuration facilitates transcatheter delivery of the system 2100. After delivery of the system 2100 to a desired position (e.g., across the septal wall), an inflatable element such as a balloon 2360 can be inserted into the inner lumen 2330 of the system 2100 while the system 2100 is still in a low profile delivery configuration. The balloon can then be inflated. Inflating the balloon expands the system 2100 to a deployed configuration, as shown in FIG. 23B. The balloon can then be deflated and removed. As shown in FIG. 23C, the system 2100 remains in the deployed position. Once deployed, the system 2100 can be selectively actuated to adjust the diameter of the inner lumen. In other embodiments, the system 2100 can be biased toward its deployed configuration so that upon deployment from a delivery catheter or sheath, the system 2100 automatically expands radially outward in the deployed configuration, without requiring mechanical inflation via the balloon 2360.

[0137] In some embodiments, the system 2100 can be adjusted using an actuation assembly implanted with the device (not shown). In some embodiments, an actuation assembly is included on the system 2100 to actively adjust the diameter of the inner lumen by actuating one or more connecting struts 2140, which in turn changes the position of the struts 2134. In some embodiments, for example, when actuated, the actuation assembly retracts the proximal ends 2132 distally, so that the struts 2134 are bent as described above with respect to FIGS. 21B-21D. The actuation assembly can also be configured to directly bend the struts 2134 to change the diameter of the lumen 2130. In some embodiments, the actuation assembly can be a motor. Additionally, other materials capable of converting energy into linear motion (e.g., Nitinol) can be used. In some embodiments, the Nitinol element is coupled to a pole or other mechanical element that is movable by actuation of the Nitinol element.

[0138] In addition to the diameter of the lumen, the shape of the lumen can also facilitate flow through the system 2100. For example, referring back to FIGS. 21B-21D, the second connecting strut 2140c can define a funnel-shaped inflow component 2137 configured for fluid communication with the LA (not shown) of the heart, and the lumen 2130 can include a cylindrically-shaped outflow portion 2139 configured for fluid communication with the RA (not shown) of the heart. As shown in FIG. 21C, the cylindrically-shaped outflow portion 2139 can have a length L1, and the adjacent funnel-shaped inflow component 2137 can have a length L2. The diameter of the lumen 2130 within the cylindrically-shaped outflow portion 2139 along the length L1 is substantially constant. The substantially constant diameter of the lumen 2130 along the length L1 is less than the variable diameter of the funnel-shaped inflow component 2137 along the length L2. In the illustrated embodiment, the length L1 is shown as greater than the length L2, but other embodiments have a length L2 greater than the length L1. In some embodiments, the length L1 extends along a majority of the length of the lumen 2130, and the length L2 extends along a minor portion of the length of the lumen 2130. In other embodiments, the struts 2134 defining the cylindrically shaped outflow portion 2139 extend between the distal inflow aperture and the proximal outflow aperture, and the funnel shaped inflow component 2137 is absent. Also, the cylindrically shaped outflow portion 2139 can have other non-circular cross-sectional shapes having substantially constant internal dimensions along the length L1. For example, the cross-sectional shape of the outflow portion having the length L1 can be elliptical, triangular, rectangular, pentagonal, etc.

[0139] When the system 2100 is implanted in the heart, blood flows into the lumen 2130 at the funnel-shaped inflow component 2137 (e.g., through the distal inflow aperture) and into the RA through the cylindrical outflow section 2139. In an exemplary embodiment, the combination of the funnel-shaped inflow component 2137 and the cylindrical outflow section 2139 is expected to provide the system 2100 with several beneficial flow characteristics. For example, the funnel-shaped inflow component 2137 can increase the blood flow rate from the LA into the lumen 2130. The relatively larger distal inflow aperture can allow for a larger blood volume to be collected. Blood then flows from the relatively larger diameter funnel-shaped inflow component 2137 to the relatively smaller diameter cylindrical outflow section 2139. Based on the Venturi effect (Bernoulli's principle in mathematical terms), pressure decreases downstream and flow velocity increases as blood flows from the funnel-shaped inlet component 2137 to the relatively small diameter cylindrical outlet section 2139. In an exemplary embodiment, the outlet section 2139 comprises a cylindrical shape having a substantially constant diameter along the length L1. The cylindrical outlet section 2139 maintains a flow rate therethrough. In contrast, the funnel-shaped outlet acts as a diffuser. Based on Bernoulli's principle, the expanding diameter at the outlet reduces the flow velocity. The exemplary cylindrical outlet reduces the swirl effect and turbulence from the inlet section while minimizing the pressure rise. The combination of these effects is expected to promote blood flow between the LA and RA. Additionally, as shown in FIGS. 21B-21D, the device retains the funnel-shaped inlet component 2137 and the cylindrical outlet section 2139 when transitioning between configurations.

[0140] Those skilled in the art will appreciate from the description herein that other lumen shapes are possible and within the scope of the present technology. In some embodiments, for example, the lumen does not include a funnel-shaped inlet component, but rather maintains a substantially constant diameter along substantially the entire length of the lumen. For example, the lumen can be substantially cylindrical with a substantially constant diameter extending between the distal and proximal ends. In other embodiments, the lumen is tapered and has a variable diameter extending between the distal and proximal ends. For example, the lumen can include a relatively large inflow aperture at the distal end and a relatively small outflow aperture at the proximal end, with the lumen tapering inwardly between the inflow and outflow apertures to form a funnel shape. In yet other embodiments, the lumen can have a generally hourglass shape with a central pinch point. As discussed above, varying the shape of the lumen can affect the blood flow rate through the lumen. Thus, the shape of the lumen provides an additional mechanism for facilitating improved control over the flow rate of blood between the LA and RA through a shunt configured in accordance with the present technology.

[0141] Those skilled in the art will further appreciate from the present disclosure herein that other flow control mechanisms can be used with the shunt systems described herein. For example, in some embodiments, the shunt system can include a gated valve that can be moved between a first position that blocks or at least partially blocks the flow lumen and a second position that unblocks or at least partially unblocks the flow lumen. In such embodiments, the gated valve can be coupled to one or more shape memory elements that can be operated using energy, such as energy stored in an energy storage component or energy directly applied to the shape memory elements via an energy source positioned external to the patient. As another example, the shunt system can include one or more shape memory coils wrapped around a portion of the shunt element that defines the flow lumen. The shape memory coils can be selectively wound or unwound to restrict (e.g., clamp) or loosen (e.g., unclamp) a portion of the flow lumen. In yet other embodiments, the shunt element can include a flexible bladder that is filled with a fluid or gas. The flexible bladder can be generally toroidal in shape to define a flow lumen therethrough. Fluid or gas can be directed into or out of the bladder to reduce or expand the size of the lumen. In yet other embodiments, the shunt element can incorporate at least partially passive concepts that can adjust the size or shape of the flow lumen based on the pressure differential between the two heart chambers. Thus, the systems described herein are not limited to the flow control mechanisms and / or shunt devices explicitly described herein. Other suitable shunt devices can be utilized and are within the scope of the present technology.

[0142] D. Shunt Assembly with Adjustable Inflow and / or Outflow Orifices FIG. 24 illustrates an inter-atrial shunt system / device 2400 ("device 2400") configured in accordance with selected embodiments of the present technology. The device 2400 includes a shunt element 2410 having a lumen 2401 extending therethrough. When the device 2400 is implanted across a septal wall (not shown), the lumen 2401 is configured to fluidly connect the LA and RA and facilitate blood flow therebetween. The shunt element 2410 can include a frame 2412 or other outer scaffold (e.g., a stent-like structure). The frame 2412 can extend circumferentially around a diameter of the shunt element 2410. In some embodiments, the frame 2412 is constructed from a material configured to be relatively flexible above body temperature (e.g., Nitinol in a material state exhibiting superelastic properties). The frame 2412 can include a central portion having a plurality of first struts 2411 arranged in a diamond shape, although other suitable strut shapes and configurations can be used. The frame 2412 can further include a plurality of second struts 2413, described in more detail below, that extend from the first struts 2411 and can be angled radially inward toward the orifice 2405 (e.g., the RA or outflow orifice) of the lumen 2401. In the illustrated embodiment, the orifice 2405 is generally circular, although other embodiments can have other shapes, such as oval, square, rectangular, polygonal, curved, etc.

[0143] The frame 2412 can further include a plurality of first anchor elements 2414 extending from a first end of the frame 2412 and a plurality of second anchor elements 2416 extending from a second end of the frame 2412 generally opposite the first end. In the illustrated embodiment, the plurality of first anchor elements 2414 and the plurality of second anchor elements 2416 extend around the entire circumference of the frame 2412, but other embodiments can have different suitable configurations. For example, in other embodiments, the anchor elements 2414 and / or 2416 can be a single element (e.g., a coil-shaped element). The first anchor element 2414 and the second anchor element 2416 can engage autologous tissue to secure the device 2400 in a desired position. For example, the first anchor element 2414 and the second anchor element 2416 can secure the device 2400 to the septal wall such that the lumen 2401 fluidly connects the LA and RA. In such embodiments, the first anchor element 2414 can be positionable in the RA and configured to engage the RA side of the septal wall, and the second anchor element 2416 can be positionable in the LA and configured to engage the LA side of the septal wall. A portion of the septal wall can be received between the first anchor element 2414 and the second anchor element 2416. In other embodiments, the orientation of the device can be reversed such that the first anchor element 2414 is positionable in the LA and the second anchor element 2416 is positionable in the RA. In some embodiments, the first anchor element 2414 and / or the second anchor element 2416 are integral with the frame 2412. In other embodiments, the first anchor element 2414 and / or the second anchor element 2416 are secured to the frame 2412 using techniques known in the art (e.g., welding, gluing, suturing, etc.).

[0144] The shunt element 2410 can include a membrane 2430 coupled (e.g., affixed, attached, or otherwise connected) to the frame 2412. In some embodiments, the membrane 2430 can be made of a material that is flexible and impermeable to or otherwise resistant to blood flow therethrough. In some embodiments, for example, the membrane 2430 can be made of a thin, elastic material, such as a polymer. For example, the membrane 2430 can be made of polytetrafluoroethylene (PTFE), ePTFE (ePTFE), silicone, nylon, polyethylene terephthalate (PET), polyether block amide (pebax), polyurethane, blends or combinations of these materials, or other suitable materials. The membrane 2430 can cover and / or encapsulate at least a portion of the shunt element 2410, such as an inner or outer surface of the shunt element 2410 between a first end positionable within the LA and a second end positionable within the RA. The membrane 2430 can extend circumferentially around the frame 2412 to at least partially surround and enclose the lumen 2401, thereby defining (at least in part) a blood flow path when implanted across the septal wall.

[0145] In some embodiments, the membrane 2430 includes a first membrane portion 2432 coupled to a second membrane portion 2434. The first membrane portion 2432 can be operatively coupled to and / or extending around a central portion of the frame 2412 (e.g., the portion including the first struts 2411). In some embodiments, the first membrane portion 2432 can also include a flange portion 2433 operatively coupled to and / or extending around the second anchor element 2416. The second membrane portion 2434 can be operatively coupled to and / or extending around a plurality of second struts 2413 that are angled radially inwardly towards the orifice 2405. The second membrane portion 2434 is at least partially cone- or funnel-shaped and can extend beyond the second strut 2413 such that at least a portion of the second membrane portion 2434 is positioned over and partially covers the lumen 2401, thereby defining the orifice 2405. The first membrane portion 2432 can be secured to the second membrane portion 2434 via suturing or other suitable techniques. In other embodiments, the membrane 2430 is a unitary membrane including both the first membrane portion 2432 and the second membrane portion 2434.

[0146] The device 2400 can further include an actuation assembly 2418 configured to change the geometry (e.g., size and / or shape) of the orifice 2405. The actuation assembly 2418 can include a flow control element 2420, a plurality of first actuation elements 2422a, and a plurality of second actuation elements 2422b. As described in more detail below, the first actuation element 2422a and / or the second actuation element 2422b can be selectively actuated to change the geometry of the flow control element 2420. This, in turn, adjusts (e.g., stretches and / or compresses) the second membrane portion 2434 that surrounds and defines the orifice 2405. As previously described, when the device 2400 is implanted across the septal wall, blood can flow between the LA and RA via the lumen 2401. Thus, changing the geometry of the orifice 2405 is expected to change the relative flow resistance and / or the amount of blood flowing between the LA and RA.

[0147] The flow control element 2420 of the device 2400 generally extends around the circumference of the orifice 2405 and at least partially defines the geometry of the orifice 2405. For example, the flow control element 2420 can be an annular (e.g., ring-like) structure coupled to the second membrane portion 2434. In embodiments in which the orifice 2405 has another shape (e.g., square), the flow control element 2420 can have a generally similar shape (e.g., square) such that the flow control element 2420 extends around the circumference of the orifice 2405. The flow control element 2420 can be flexible such that it can expand and contract to change the geometry (e.g., diameter) of the orifice 2405. For example, when the flow control element 2420 moves (e.g., expands) in a first manner, the diameter of the orifice 2405 increases, thereby reducing the flow resistance through the lumen 2401. When the flow control element 2420 moves in a second manner opposite the first manner (eg, contracts), the diameter of the orifice 2405 decreases, thereby increasing the flow resistance through the lumen.

[0148] The shape of the flow control element 2420 can be controlled at least in part via the plurality of first actuating elements 2422a and the plurality of second actuating elements 2422b. As described in detail with respect to Figures 25A-25D, the plurality of first actuating elements 2422a and the plurality of second actuating elements 2422b can be coupled to the flow control element 2420 at a first end and anchored to a frame 2412 or another suitable generally stationary structure at a second end. The plurality of first actuating elements 2422a and the plurality of second actuating elements 2422b can be positioned radially around the flow control element 2420 (e.g., in a "spoke-like" configuration, where the orifices form a central hub from which the actuating elements extend outward as spokes).

[0149] The first and second actuating elements 2422a and 2422b may be composed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the first and second actuating elements 2422a and 2422b may be transitionable between a first material state (e.g., martensitic state, R-phase, etc.) and a second material state (e.g., R-phase, austenitic state, etc.). In the first state, the first and second actuating elements 2422a and 2422b may be relatively deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the first and second actuating elements 2422a and 2422b may have a preference for a particular manufacturing geometry (e.g., shape, length, and / or size). The first and second actuating elements 2422a and 2422b may be transitionable between the first and second states by providing energy (e.g., heat) to the actuating elements to heat the actuating elements above a transition temperature. In some embodiments, the transition temperatures of both the first actuating element 2422a and the second actuating element 2422b are greater than average body temperature. Thus, both the first actuating element 2422a and the second actuating element 2422b are typically in a deformable first state when the device 2400 is implanted within the body until they are heated (e.g., activated).

[0150] If the actuating elements (e.g., first actuating element 2422a) are deformed relative to their manufactured geometry while in a first state, heating the actuating elements (e.g., first actuating element 2422a) above their transition temperature transitions the actuating elements from the deformed shape toward the manufactured shape by transitioning to a second state. As described in more detail below, heat can be applied to the actuating elements by RF heating, resistive heating, etc. In some embodiments, the first actuating element 2422a can be selectively heated independently from the second actuating element 2422b, and the second actuating element 2422b can be selectively heated independently from the first actuating element 2422a. In some embodiments, a portion of an actuating element (e.g., first nitinol portion 2422a1 or second nitinol portion 2422a2 (FIG. 3A)) can be heated independently from other portions of the same actuating element. As described in more detail below, selectively heating the first actuating element 2422a (or a portion of the first actuating element 2422a) causes the diameter of the lumen 2401 to decrease, and selectively heating the second actuating element 2422b (or a portion of the second actuating element 2422b) causes the diameter of the lumen 2401 to increase.

[0151] 25A-25D illustrate, among other things, how the first actuating element 2422a and the second actuating element 2422b can vary the diameter of the orifice 2405. Some features of the device 2400 are not shown in FIGS. 25A-25D for clarity. Referring initially to FIG. 25A, for example, the first actuating element 2422a and the second actuating element 2422b are shown prior to being secured to the shunt element 2410 and / or the frame 2412 (FIG. 24). In particular, the first actuating element 2422a and the second actuating element 2422b are in their manufactured configurations. As will be apparent to one of ordinary skill in the art from the disclosure herein, the first actuating element 2422a and the second actuating element 2422b generally have different manufactured configurations such that the flow control element 2420 can be driven through multiple configurations by actuating the actuating elements 2422a / 2422b. For example, in the illustrated configuration, the first actuating element 2422a generally has a longer length than the second actuating element 2422b when in their manufactured configuration.

[0152] Each first actuating element 2422a can further include (or be coupled to) a first clip element 2524a having a first fixation element 2526a. The first fixation element 2526a can fix the corresponding first actuating element 2422a to the frame 2412, or another suitable component of the device 2400 (FIG. 25B). For example, the first fixation element 2526a can include an aperture to facilitate suturing the first clip element 2524a to the frame 2412. The first clip element 2524a can further include a first hole 2525a. Together, the first clip element 2524a and the first hole 2525a form an electrical connection point that can receive and transmit electricity through the corresponding first actuating element 2422a to resistively heat the first actuating element 2422a. In the illustrated embodiment, each of the first actuating elements 2422a can generally form a "U" or "V" shape, such that a valley of the "U" or "V" is coupled to the flow control element 2420. For example, each of the first actuating elements 2422a can include a first nitinol portion 2522a1 coupled to a second nitinol portion 2522a2. The first nitinol portion 2522a1 and the second nitinol portion 2522a2 can be electrically coupled such that an electrical current delivered to the first nitinol portion 2522a1 also flows through the second nitinol portion 2522a2, and vice versa. Thus, the first nitinol portion 2522a1 and the second nitinol portion 2522a2 can form an electrical circuit for resistively heating the first actuating element 2422a. First nitinol portion 2522a1 and second nitinol portion 2522a2 can be comprised of a unitary (eg, single) structure or can include separate elements that are bonded together.

[0153] Similarly, each second actuation element 2422b can further include (or be coupled to) a second clip element 2524b having a second fixation element 2526b. The second fixation element 2526b can fix the corresponding second actuation element 2422b to the frame 2412, or another suitable component of the device 2400 (FIG. 24). For example, the second fixation element 2526b can include an aperture to facilitate suturing the second clip element 2524b to the frame 2412. The second clip element 2524b can further include a second hole 2525b. Together, the second clip element 2524b and the second hole 2525b form an electrical connection point that can receive electrical energy that can be directed through the corresponding second actuation element 2422b to resistively heat the second actuation element 2422b. In the illustrated embodiment, each of the second actuating elements 2422b can generally form a "U" or "V" shape, such that a valley of the "U" or "V" is coupled to the flow control element 2420. For example, each of the second actuating elements 2422b can include a first nitinol portion 2522b1 coupled to a second nitinol portion 2522b2. The first nitinol portion 2522b1 and the second nitinol portion 2522b2 can be electrically coupled such that an electrical current delivered to the first nitinol portion 2522b1 also flows through the second nitinol portion 2522b2, and vice versa. Thus, the first nitinol portion 2522b1 and the second nitinol portion 2522b2 can form an electrical circuit for resistively heating the second actuating element 2422b. The first nitinol portion 2522b1 and the second nitinol portion 2522b2 can be comprised of a unitary (eg, single) structure or can include separate elements that are bonded together.

[0154] FIG. 25B is a schematic diagram of an embodiment of the device 2400 after the first actuating element 2422a and the second actuating element 2422b have been secured to the shunt element 2410 via corresponding first and second fixation elements 2526a and 2526b (FIG. 2). In particular, FIG. 25B shows the device 2400 in a first configuration (e.g., a composite configuration) in which both the first actuating element 2422a and the second actuating element 2422b are at least partially deformed relative to their manufactured geometry configurations. To secure the first actuating element 2422a to the shunt element 2410 (FIG. 2), the first actuating element 2422a is compressed (e.g., shortened) relative to their manufactured geometry (FIG. 25A). To secure the second actuating element 2422b to the shunt element 2410 (FIG. 2), the second actuating element 2422b is stretched (e.g., lengthened) relative to their manufactured geometry (FIG. 25B). Both first actuating element 2422a and second actuating element 2422b are unheated (e.g., at room or body temperature) and therefore in a relatively malleable material state (e.g., a martensitic state) and therefore retain the deformed position shown in Figure 25B. In the first configuration shown in Figure 25B, the orifice 2405 defined by second membrane portion 2434 and / or flow control element 2420 has a first diameter D1.

[0155] FIG. 25C illustrates the device 2400 in a second configuration different from the first (e.g., composite) configuration. In particular, in the second configuration, the device 2400 is actuated relative to the first configuration illustrated in FIG. 25B, causing the first actuating elements 2422a to transition from a first (e.g., martensite) material state to a second (e.g., austenite) material state. Because the first actuating elements 2422a were deformed (e.g., compressed) relative to their manufactured geometry while in the first (e.g., composite) configuration, heating the first actuating elements 2422a above the transition temperature causes the first actuating elements 2422a to expand in length as they move toward their manufactured geometry ( FIG. 25A ). As described above, the first actuating elements 2422a are secured to the frame 2412, or another generally stationary structure on the shunt element 2410, via the first securing element 2526a. Thus, the first actuating elements 2422a compress the flow control elements 2420 radially inward as they expand in length toward their manufactured geometry. This causes the second membrane to move radially inward to deform (e.g., stretch, relax, etc.) and the orifice 2405 to assume a second diameter D2, which is smaller than the first diameter D1. Moreover, because the flow control element 2420 is coupled to the second actuating element 2422b, the expansion of the first actuating element 2422a (and the corresponding contraction of the flow control element 2420) also causes the second actuating elements 2422b, which are still in a deformable (e.g., martensitic) state due to not having been heated above their transition temperature, to also expand (e.g., expand in length). For example, the second actuating elements 2422b expand further from their manufactured geometry (FIG. 25A) than they were in the first (e.g., composite) configuration (FIG. 25B). When implanted in a human heart, the reduced diameter of orifice 2405 is expected to reduce the flow of blood from the LA to the RA.

[0156] FIG. 25D illustrates the device 2400 in a third configuration that is different from the first or second configurations. In particular, in the third configuration, the device 2400 is actuated relative to the first configuration illustrated in FIG. 25B, causing the second actuating elements 2422b to transition from a first (e.g., martensite) material state to a second (e.g., austenite) material state. Because the second actuating elements 2422b expanded relative to their manufactured geometry (e.g., when placed in either the first or second configuration), heating the second actuating elements 2422b above the transition temperature causes the second actuating elements 2422b to contract in length as they move toward their manufactured geometry (FIG. 25A). As described above, the second actuating elements 2422b are secured to the frame 2412, or another generally stationary structure on the shunt element 2410, via the second fixing element 2526b. Thus, the second actuating elements 2422b cause the flow control element 2420 to expand radially outward as they contract in length toward their manufactured geometry. Because the flow control element 2420 is coupled to the second membrane portion 2434, the second membrane portion 2434 is deformed (e.g., compressed, relaxed, etc.) to move radially outward, and the orifice 2405 assumes a third diameter D3 that is greater than the first diameter D1 and the second diameter D2. Moreover, because the flow control element 2420 is coupled to the first actuating element 2422a, the contraction of the second actuating element 2422b (and the corresponding expansion of the flow control element 2420) also causes the first actuating elements 2422a to contract (e.g., reduce in length) since they are still in a deformable (e.g., martensitic) state due to not having been heated above their transition temperature. For example, the first actuating elements 2422a are compressed further from their manufactured geometry (FIG. 25A) than they were in the first (e.g., composite) configuration (FIG. 25B). When implanted in a human heart, the enlarged diameter of orifice 2405 is expected to increase the flow of blood from the LA to the RA.

[0157] The device 2400 can be repeatedly transitioned between the second and third configurations. For example, the device 2400 can be transitioned from the third configuration back to the second configuration by heating the first actuating elements 2422a above their transition temperature, which transitions the second actuating elements 2422b back to their deformable first state (e.g., by heating the second actuating elements 2422b and then allowing them to cool below the transition temperature). Heating the first actuating elements 2422a above their transition temperature moves the first actuating elements toward their manufactured geometry, which in turn pushes the flow control elements 2420 radially inward, transitioning the device 2400 to the second configuration (FIG. 25C).

[0158] In some embodiments, the device 2400 can also transition to or from an intermediate configuration between the second and third configurations. In some embodiments, for example, the device 2400 can first transition from a first composite configuration to the second, third, or another configuration (e.g., the device may transition to the third or another configuration before actuating to the second configuration). In some embodiments, the configuration of the device 2400 can change without inducing a change in the material state of either the first actuating element 2422a or the second actuating element 2422b. This can be accomplished, for example, by direct mechanical methods of applying an external force to a component or portion of the device (e.g., by balloon inflation of the flow control element 2420, similar to that described above with respect to FIGS. 23A-23C).

[0159] Thus, the device 2400 can be selectively transitioned between various configurations by selectively activating some or all of either the first actuating element 2422a or the second actuating element 2422b. After actuation, the device 2400 can be configured to substantially retain a given configuration until further actuation of the opposing actuating element. In some embodiments, the device 2400 can be transitioned to an intermediate configuration between the second and third configurations (e.g., the first configuration) by heating some but not all of either the first actuating element 2422a or the second actuating element 2422b.

[0160] As defined above, heat can be applied to the actuating elements by RF heating, resistive heating, etc. In some embodiments, the first actuating element 2422a can be selectively heated independently of the second actuating element 2422b, and the second actuating element 2422b can be selectively heated independently of the first actuating element 2422a. For example, in some embodiments, the first actuating element 2422a is on a first electrical circuit for selectively and resistively heating the first actuating element 2422a, and the second actuating element 2422b is on a second electrical circuit for selectively and resistively heating the second actuating element 2422b. As described in detail above, selectively heating the first actuating element 2422a reduces the diameter of the orifice 2405, and selectively heating the second actuating element 2422b increases the diameter of the orifice 2405. In some embodiments, each individual first actuation element 2422a is on its own selectively and independently actuable electrical circuit and each individual second actuation element 2422b is on its own selectively and independently actuable electrical circuit. Without being limited by theory, this allows for a high granularity of potential adjustment to the diameter of the orifice 2405 through the selective actuation of the individual actuation elements.

[0161] In some embodiments, the actuating elements may be configured differently. For example, in some embodiments, both the first actuating element 2422a and the second actuating element 2422b compress (or alternatively expand) from their manufactured geometries when placed in an initial composite configuration. For example, each set of actuating elements may compress (or alternatively expand) a different amount. Alternative embodiments may include more than two sets of actuating elements that are manufactured to have two or more manufactured geometries.

[0162] 26 illustrates an adjustable interatrial device 2600 ("device 2600") configured in accordance with selected embodiments of the present technology. Device 2600 may include certain features generally similar to those described above with respect to device 2400. For example, device 2600 includes a shunt element 2610 including a frame 2612 and a membrane 2630 disposed about and / or coupled to the frame 2612. The shunt element 2610 defines a lumen 2601 that extends therethrough and fluidly connects the LA and RA. The membrane 2630 extends radially inward at a first (e.g., RA) end of the shunt element 2610 and defines an orifice 2605. As described below, the shape and / or size (e.g., diameter) of the orifice 2605 can be selectively adjusted via an actuation assembly 2618 to control the flow rate of blood through the lumen 2601. The actuation assembly 2618 can include an actuation element 2622 and a flow control element 2620.

[0163] However, in contrast to the device 2400 described above, the device 2600 incorporates an actuatable flow control element 2620 disposed around the orifice 2605 (e.g., the flow control element 2620 is an annular actuating element). For example, the flow control element 2620 can be constructed from a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the flow control element 2620 can be transitionable between a first material state (e.g., martensitic state, R-phase, etc.) and a second material state (e.g., R-phase, austenitic state, etc.). In the first state, the flow control element 2620 can be deformable (e.g., plastic, malleable, compressible, expansive, etc.). In the second state, the flow control element 2620 can have a preference for a particular manufacturing geometry (e.g., shape, diameter, and / or dimensions). The flow control element 2620 can be transitioned between the first state and the second state by applying energy to heat the flow control element 2620 above a transition temperature. Heating the flow control element 2620 above its transition temperature to transition the material to the second state causes the flow control element 2620 to move toward its manufactured geometry. If the flow control element 2620 is deformed relative to its manufactured geometry while in the first state, these deformations can be partially or fully restored when the material transitions to the second state. In some embodiments, the transition temperature of the flow control element 2620 is greater than average body temperature. In some embodiments, the flow control element 2620 can be heated by RF energy, resistive heating, or the like. The flow control element 2620 can be bonded to the membrane 2630 such that dimensional adjustments to the flow control element 2620 impart a corresponding dimensional change to the orifice 2605.

[0164] The device 2600 further includes a plurality of actuating elements 2622 arranged radially around the flow control element 2620. The plurality of actuating elements 2622 can be generally similar to the plurality of first actuating elements 2422a described above with respect to FIGS. 24-25D. However, because the flow control element 2620 is actuable, the device 2600 does not necessarily require a plurality of second actuating elements positioned radially around the flow control element 2620 (e.g., as opposed to the second actuating element 2422b of the device 2400). Instead, the flow control element 2620 takes over the function of the second actuating elements, as described below. The actuating element 2622 can be heated independently of the flow control element 2620. For example, in some embodiments, the actuating element 2622 can be on a different electrical circuit than the flow control element 2620.

[0165] The device 2600 can be transitioned between various configurations by selectively heating either the flow control element 2620 or the actuating element 2622 (or alternatively, by directly applying a mechanical force to the flow control element 2620 while it is in a relatively deformable (e.g., martensite) material state). The illustrated configurations may be composite configurations, for example, in which both the flow control element 2620 and the actuating element 2622 are deformed relative to their manufactured geometries. For example, the actuating element 2622 may be compressed (e.g., shortened) relative to their manufactured geometry, and the flow control element 2620 may be compressed (e.g., to have a smaller diameter) relative to its manufactured geometry. Thus, to enlarge the diameter of the orifice, the flow control element 2620 can be heated above its transition temperature (while the actuating element remains below the transition temperature), transitioning from a first state (e.g., a martensite state) to a second state (e.g., an austenite state), and a change in configuration toward its manufactured geometry can be induced by the shape memory effect. To reduce the diameter of the orifice, the actuating elements 2622 can be heated above a transition temperature (while the flow control element 2620 remains below its transition temperature) to transition from a first state (e.g., a martensitic state) to a second state (e.g., an austenitic state) and a shape memory effect can induce a change in configuration toward their manufactured geometry. In other embodiments, the actuating elements 2622 can expand (e.g., lengthen) relative to their manufactured geometry and the flow control element 2620 can expand (e.g., to have a larger diameter) relative to its manufactured geometry when the device 2600 is in the composite configuration. In such embodiments, the actuating element 2622 is selectively heated to increase the diameter of the orifice 2605 and the flow control element 2620 is selectively heated to decrease the diameter of the orifice 2605. In some embodiments, stabilizing features (not shown) may be included near the actuating element 2622 to restrict movement of the actuating element in a desired manner (e.g., restricting movement only or primarily to the plane of the element's long axis).Such features can facilitate the transfer of force and / or motion between various aspects of device 2600, such as between actuation element 2622, flow control element 2620, and membrane 2630. In embodiments, any number of sets of flow control elements and actuation elements may be used in combination with each other.

[0166] 27 illustrates an adjustable interatrial device 2700 ("device 2700") configured in accordance with selected embodiments of the present technology. Device 2700 may include certain features generally similar to those described above with respect to devices 2400 and 2600. For example, device 2700 includes a shunt element 2710 including a frame 2712 and a membrane 2730 disposed about and / or coupled to the frame 2712. The shunt element 2710 defines a lumen 2701 that extends therethrough and fluidly connects the LA and RA. The membrane 2730 extends radially inward at a first (e.g., RA) end of the shunt element 2710 and defines an orifice 2705. As described below, the shape and / or size (eg, diameter) of orifice 2705 can be selectively adjusted via actuation assembly 2718 to control the flow rate of blood through lumen 2701.

[0167] The actuation assembly 2718 includes two independently actuable flow control elements. In particular, the actuation assembly 2718 includes a first actuable flow control element 2720a and a second actuable flow control element 2720b. Thus, in some embodiments, the device 2700 does not include other actuating elements (e.g., actuating elements 2422a, 2422b, described with respect to FIGS. 24-25D, etc.) that are different from the flow control elements 2720a, 2720b. Rather, the flow control elements 2720a, 2720b are themselves actuating elements (and thus the flow control elements 2720a, b can also be referred to as first and second actuating elements). The first flow control element 2720a is disposed circumferentially around the second flow control element 2720b. Both the first flow control element 2720a and the second flow control element 2720b are coupled to the membrane 2730 such that adjustments to either the first flow control element 2720a or the second flow control element 2720b impart a corresponding dimensional change to the orifice 2705.

[0168] The first flow control element 2720a and the second flow control element 2720b can be composed of a shape memory material, such as a shape memory alloy (e.g., Nitinol). Thus, the first flow control element 2720a and the second flow control element 2720b can be transitionable between a first state (e.g., martensitic state, R-phase, etc.) and a second state (e.g., R-phase, austenitic state, etc.). In the first state, the first flow control element 2720a and the second flow control element 2720b can be deformable (e.g., malleable, compressible, expansive, etc.). In the second state, the first flow control element 2720a and the second flow control element 2720b can have a preference for a particular manufacturing geometry (e.g., shape, length, and / or dimensions). The first flow control element 2720a and the second flow control element 2720b can be transitioned between the first state and the second state by providing energy to an actuation element to heat the flow control element above a transition temperature. In some embodiments, the transition temperatures of both the first flow control element 2720a and the second flow control element 2720b are greater than average body temperature. Thus, both the first flow control element 2720a and the second flow control element 2720b are normally in a deformable first state when the device 2700 is implanted within the body, except when they are heated (e.g., activated).

[0169] When the flow control elements (e.g., first flow control element 2720a) are heated above their transition temperature, the flow control elements transition to the second state and thus toward their manufactured geometry. If the flow control elements (e.g., first flow control element 2720a) are deformed while in the first state, these deformations can be partially or fully restored when the material transitions to the second state. Heat can be applied to the flow control elements by RF heating, resistive heating, or the like. In some embodiments, the first flow control element 2720a can be selectively heated independently of the second flow control element 2720b, and the second flow control element 2720b can be selectively heated independently of the first flow control element 2720a. As described in more detail below, selective heating of the first flow control element 2720a reduces the diameter of the orifice 2705, and selective heating of the second flow control element 2720b increases the diameter of the orifice 2705. 27, in an embodiment, any number of flow control elements may be integrated into device 2700. One advantage of using more elements may be greater precision and / or granularity regarding the size and / or shape changes that can be induced at orifice 2705.

[0170] The device 2700 can be transitioned between various configurations by selectively heating either the first flow control element 2720a or the second flow control element 2720b. The illustrated configuration may be a composite configuration in which both the first flow control element 2720a and the second flow control element 2720b are deformed relative to their manufactured geometries. For example, the first flow control element 2720a may expand (e.g., to have a larger diameter) relative to its manufactured geometry, and the second flow control element 2720b may compress (e.g., to have a smaller diameter) relative to its manufactured geometry. Thus, to enlarge the size (e.g., diameter) of the orifice 2705, the second flow control element 2720b can transition from a relatively malleable first state (e.g., a martensitic state) to a second state (e.g., an austenitic state) and move toward its manufactured geometry when heated above its transition temperature (while the first flow control element remains below the transition temperature). To reduce the size (e.g., diameter) of the orifice 2705, the first flow control element 2720a can transition from a relatively malleable first state (e.g., a martensitic state) to a second state (e.g., an austenitic state) and move toward its manufactured geometry when heated above a transition temperature (while the second flow control element 2720b remains below its transition temperature).

[0171] 28A-28D illustrate an adjustable interatrial system 2800 ("system 2800") configured in accordance with selected embodiments of the present technology. More specifically, FIG. 28A is a partial isometric view of system 2800 in a first configuration from the RA side of the septal wall S, FIG. 28B is a partial isometric view of system 2800 in a first configuration from the LA side of the septal wall S, FIG. 28C is a partial isometric view of system 2800 in a second configuration from the RA side of the septal wall S, and FIG. 28D is a partial isometric view of system 2800 in a second configuration from the LA side of the septal wall S. System 2800 can include certain features generally similar to those described above with respect to devices 2400, 2600, and 2700. For example, system 2800 includes a shunt element 2810 including a frame 2812 and a membrane 2830 disposed about and / or coupled to frame 2812. The shunt element 2810 may further include one or more anchors 2814 for securing the shunt element 2810 in place. The shunt element 2810 defines a lumen 2801 that extends therethrough and fluidly connects the LA and RA. A membrane 2830 extends radially inward at a first (e.g., RA) end of the shunt element 2810 and defines an orifice 2805. As described below, the shape and / or size (e.g., diameter) of the orifice 2805 can be selectively adjusted via an actuation assembly 2818 to control the flow rate of blood through the lumen 2801.

[0172] 28E-28H show additional details of the actuating assembly 2818. The actuating assembly 2818 can include a first stent-like actuating element 2820 and a second stent-like actuating element 2822. The first and second actuating elements 2820, 2822 can be tapered or otherwise angled radially inward and extend from the frame 2812 toward the orifice 2805. Some aspects of the first and second actuating elements 2820, 2822 can be generally similar to the nested stent-like actuating elements described above with respect to FIGS. 3A-4C. For example, FIG. 29E shows the first and second actuating elements 2820, 2822 in their manufactured configurations (e.g., prior to deformation and bonding). FIG. 29F shows a composite configuration in which the first actuating element 2820 is nested within the second actuating element 2822 and both the first and second actuating elements 2820, 2822 are deformed relative to their manufactured geometries. Figure 29G shows the second configuration after the first actuating element 2822 has been heated above its transition temperature, thereby transitioning towards its manufactured geometry and causing the compound diameter of the nested actuating elements to expand (and thus the diameter of the orifice 2805 to expand, as shown in Figure 28C), and Figure 29H shows the third configuration after the second actuating element 2822 has been heated above its transition temperature, thereby transitioning towards its manufactured geometry and causing the compound diameter of the nested actuating elements to decrease (and thus the diameter of the orifice 2805 to decrease, as shown in Figure 28A).

[0173] 28A-28D, unlike the telescoping actuation elements described with respect to FIGS. 3A-4C, the first and second actuation elements 2820, 2822 are positioned within or coupled to a distal portion of the membrane 2830 that resides within the RA, rather than a central portion of the membrane 2830 that resides across the septal wall. By positioning the telescoping actuation elements within the distal portion of the membrane 2830, the geometry of the orifice 2805 can be adjusted while the geometry of the central portion of the lumen 2801 is maintained (e.g., as defined by the central portion of the membrane 2830). Thus, rather than adjusting the geometry of a substantial portion of the lumen 2801, the actuation assembly 2818 allows the user to selectively adjust the diameter of a portion of the lumen 2801 (e.g., at and adjacent to the orifice 2805). The system 2800 may also include one or more energy storage components 2850 (e.g., batteries, supercapacitors, etc.) to store energy that can be used to resistively heat the first and / or second actuating elements 2820, 2822.

[0174] 29A-29D illustrate an adjustable interatrial system 2900 ("system 2900") configured in accordance with further embodiments of the present technology. More specifically, FIG. 29A is a partial isometric view of system 2900 in a first configuration from the RA side of the septal wall S, FIG. 29B is a partial isometric view of system 2900 in a first configuration from the LA side of the septal wall S, FIG. 29C is a partial isometric view of system 2900 in a second configuration from the RA side of the septal wall S, and FIG. 29D is a partial isometric view of system 2900 in a second configuration from the LA side of the septal wall S. System 2900 can include certain features generally similar to those described above with respect to system 2800. For example, system 2900 includes a shunt element 2910 including a frame 2912 and a first membrane 2930 disposed about and / or coupled to the frame 2912. The shunt element 2910 defines a lumen 2901 that extends therethrough and fluidly connects the LA and RA. A first membrane 2930 extends radially inward at a first (e.g., RA) end of the shunt element 2910 and at least partially defines an orifice 2905. As previously described, the shape and / or size (e.g., diameter) of the orifice 2905 can be selectively adjusted via an actuation assembly to control the flow rate of blood through the lumen 2901.

[0175] In this embodiment, the system 2900 may further include a second membrane 2932 that is engaged with the frame 2912 and the first membrane 2930 and may extend at least partially over components of the system 2900 spaced from the shunt element 2910 (e.g., anchor(s), energy storage component(s), etc.). The second membrane 2932 may be constructed, for example, of a woven mesh or other suitable material. During operation of the system 2900, the second membrane 2932 is configured to at least partially insulate the energy storage component(s) from blood in the RA and LA. This arrangement is expected to further inhibit thrombus formation after implantation of the system 2900 in a patient. The second membrane 2932 is an optional component that may have a different configuration / arrangement than the embodiment shown in FIGS. 29A-29D. Additionally, in some embodiments, the second membrane 2932 may be omitted.

[0176] 30A-30E illustrate an inter-atrial shunt system 3000 ("system 3000") configured in accordance with selected embodiments of the present technology. More specifically, FIG. 30A is a perspective view of system 3000, FIG. 30B is a side view of system 3000, and FIGS. 30C-30E are schematic diagrams of an actuation assembly 3015 of system 3000 during various stages of operation. Referring initially to FIGS. 30A and 30B together, system 3000 includes a shunt element 3002 defining a lumen 3004 therethrough. Shunt element 3002 may include a first end 3003a configured to be positioned in or near the RA (not shown) and a second end 3003b configured to be positioned in or near the LA (not shown). Thus, system 3000, when implanted in a patient's septal wall (not shown), fluidly couples the LA and RA via lumen 3004. In some embodiments, the system 3000 functions as a subsystem that interfaces with additional structures (not shown), such as anchors and / or frame components, to form an inter-atrial shunt system configured in accordance with one embodiment of the present technology.

[0177] The shunt element 3002 can be a frame including a first annular element 3006a at a first end 3003a and a second annular element 3006b at a second end 3003b. The first and second annular elements 3006a-b can each extend circumferentially around the lumen 3004 to form a stent-like frame structure. In the illustrated embodiment, the first and second annular elements 3006a-b each have a serpentine shape including a plurality of respective vertices 3008a-b. The vertices 3008a-b can be curved or rounded. In other embodiments, the vertices 3008a-b can be pointed or angular such that the first and second annular elements 3006a-b have a zigzag shape. Optionally, the first and second annular elements 3006a-b can have different and / or irregular patterns of vertices 3008a-b or can be completely devoid of vertices 3008a-b. The first and second annular elements 3006a-b can be coupled to one another by a number of struts 3010 that extend longitudinally along the shunt element 3002. The struts 3010 can be positioned between the apexes 3008a-b of the first and second annular elements 3006a-b, respectively.

[0178] Additionally, the system 3000 includes a membrane 3012 operably coupled (e.g., affixed, attached, or otherwise connected) to the shunt element 3002. In some embodiments, the membrane 3012 can be made from a material that is flexible and impermeable or otherwise resistant to blood flow therethrough. In some embodiments, for example, the membrane 3012 can be made from a thin, elastic material, such as a polymer. For example, the membrane 3012 can be made from PTFE, ePTFE, silicone, nylon, PET, polyether block amide (pebax), polyurethane, blends or combinations of these materials, or other suitable materials.

[0179] The membrane 3012 can cover at least a portion of the shunt element 3002, such as an outer surface of the shunt element 3002 between the first end 3003a and the second end 3003b. The membrane 3012 can extend circumferentially around the shunt element 3002 to at least partially surround and enclose the lumen 3004. For example, in the illustrated embodiment, the membrane 3012 extends between the first annular element 3006a and the second annular element 3006b and over the struts 3010. The membrane 3012 can bond the first and second annular elements 3006a-b to one another in combination with, or as an alternative to, the struts 3010. The membrane 3012 can extend beyond the first end 3003a and / or the first annular element 3006a (e.g., as best seen in FIG. 30B) such that a portion of the membrane 3012 is positioned over and partially covers the lumen 3004. In some embodiments, the membrane 3012 does not extend beyond the second end 3003b and / or the second annular element 3006b.

[0180] The membrane 3012 includes an aperture 3014 formed therein. When the membrane 3012 is coupled to the shunt element 3002, the aperture 3014 can be at least generally aligned with or otherwise overlapping the lumen 3004 to allow blood flow therethrough. In some embodiments, the aperture 3014 is positioned at or near the first end 3003a of the shunt element 3002. In other embodiments, the aperture 3014 can be positioned at or near the second end 3003b. Additionally, although FIG. 30A illustrates the aperture 3014 as having an elliptical shape, in other embodiments, the aperture 3014 can have a different shape, such as a circle, a square, a rectangle, a polygon, or a curved shape.

[0181] The geometry (e.g., size and / or shape) of the aperture 3014 can be changed by deforming (e.g., stretching and / or compressing) or otherwise moving the portion of the membrane 3012 surrounding the aperture 3014. The change in the geometry of the aperture 3014 can affect the blood flow rate through the lumen 3004. In some embodiments, depending on the size of the aperture 3014 relative to the size of the lumen 3004, the blood flow through the lumen 3004 can be partially or totally blocked by the membrane 3012. Thus, an increase in the size (e.g., diameter, area) of the aperture 3014 can increase the blood flow rate through the lumen 3004, and a decrease in the size of the aperture 3014 can decrease the blood flow rate.

[0182] The system 3000 can include an actuation assembly 3015 operatively coupled to the aperture 3014 to selectively adjust the size of the aperture. The actuation assembly 3015 can include an actuation mechanism 3016 and a string element 3018 (e.g., a cord, thread, fiber, wire, tether, ligature, or other flexible elongated element). The actuation mechanism 3016 can be coupled to the string element 3018 around the aperture 3014 to control the size of the aperture. For example, the string element 3018 can include a loop portion 3020 that circumscribes the aperture 3014 and a linking portion 3022 that couples the loop portion 3020 to the actuation mechanism 3016. In some embodiments, the loop portion 3020 and the connecting portion 3022 are different portions of one adjacent elongated element (e.g., arranged similarly to a lasso or snare) and achieve their relative shape (e.g., an oval looped shape) as a result of how they are connected to the system 3000. In other embodiments, the loop portion 3020 and the connecting portion 3022 can be separate elements that are directly or indirectly coupled to one another.

[0183] One or more portions of the string element 3018 (e.g., loop portion 3020) can be coupled to a portion of the membrane 3012 near the aperture 3014. In the illustrated embodiment, the string element 3018 (e.g., loop portion 3020) passes through a number of openings or holes 3024 (e.g., eyelets) located near a peripheral portion of the aperture 3014. The openings 3024 can be coupled to the shunt element 3002 (e.g., first end 3003a and / or first annular element 3006a) via a number of flexible ribs 3026 (e.g., sutures, strings, threads, metallic structures, polymeric structures, etc.). In other embodiments, the openings 3024 are formed in or directly coupled to the membrane 3012 such that the ribs 3026 are omitted.

[0184] In some embodiments, the string element 3018 has a lasso-like or noose-like configuration in which the loop portion 3020 can be tightened to reduce its size or loosened to increase its size by making an adjustment (e.g., translating, rotating, tensioning, releasing, etc.) to the linking portion 3022. In some embodiments, the movement caused by the adjustment of the linking portion 3022 induces a movement in the loop portion 3020 (e.g., a movement that results in the loop portion 3020 shifting to a larger or smaller size). The bond between the string element 3018 and the membrane 3012 allows the size (e.g., diameter, area) of the aperture 3014 to change with the size of the loop portion 3020, such that the size of the aperture 3014 increases as the size of the loop portion 3020 increases and decreases as the size of the loop portion 3020 decreases. For example, as the loop portion 3020 decreases in size, the portion of the membrane 3012 surrounding the aperture 3014 may be tightened, stretched, or otherwise drawn together by the loop portion 3020, decreasing the size of the aperture 3014. Conversely, as the loop portion 3020 increases in size, the portion of the membrane 3012 surrounding the aperture may be released, loosened, stretched, or otherwise moved apart, increasing the size of the aperture 3014. Thus, the actuation mechanism 3016 can adjust the size of the loop portion 3020, and thus the size of the aperture 3014, by controlling the amount of force (e.g., tension) applied to the loop portion 3020 via the connection portion 3022. For example, in some embodiments, the actuation mechanism 3016 increases the size of the loop portion 3020 and the aperture 3014 by increasing the amount of force applied to the connecting portion 3022, and decreases the size of the loop portion 3020 and the aperture 3014 by decreasing the amount of force applied.

[0185] In other embodiments, the system 3000 can implement different mechanisms to mechanically and / or operatively couple the actuation mechanism 3016, the loop portion 3020, and the linking portion 3022. For example, there can be an inverse relationship between these components, such as the actuation mechanism 3016 can increase the size of the loop portion 3020 and the aperture 3014 by increasing the amount of force applied to the linking portion 3022, and can decrease the size of the loop portion 3020 and the aperture 3014 by decreasing the amount of force applied. In some embodiments, changes in the size of the loop portion 3020 and the aperture 3014 are caused via the actuation mechanism 3016 translating, rotating, or otherwise manipulating the linking portion 3022 in a manner that does not substantially increase or decrease the amount of force applied to the linking portion 3022. In other embodiments, adjustments made to the linking portion 3022 by the actuation mechanism 3016 can result in a change in the shape (but not the size) of the loop portion 3020 and the aperture 3014.

[0186] In some embodiments, the coupling portion 3022 can be surrounded by a relatively stiff conduit 3034 (e.g., a plastic or metal hypotube shown in FIGS. 30C-30E), which can facilitate the transmission of forces from the actuation mechanism 3016, as described further below. The conduit 3034 can be flexible or hinged such that it can move with one or more degrees of freedom relative to the actuation mechanism 3016 and / or aperture 3014.

[0187] The actuation mechanism 3016 can be configured in a number of different ways. In some embodiments, for example, the actuation mechanism 3016 includes one or more motors, such as electromagnetic motors, implantable battery and mechanical motors, MEMS motors, micro brushless DC motors, piezoelectric-based motors, solenoids, and other motors. In other embodiments, the actuation mechanism 3016 includes one or more shape memory elements. For example, referring together to FIGS. 30C-30E, in some embodiments, the actuation mechanism 3016 includes a first shape memory actuation element 3028a, a second shape memory actuation element 3028b, and a shuttle element 3030. The shuttle element 3030 can be positioned between and coupled to the first shape memory actuation element 3028a and the second shape memory actuation element 3028b. Also, the shuttle element 3030 can be coupled to the string element 3018 (e.g., coupled to the linking portion 3022). Optionally, the first shape memory actuating element 3028a, the second shape memory actuating element 3028b, and the shuttle element 3030 can be located within a housing 3032. The shuttle element 3030 can move within the housing 3032 to adjust the force on and / or the position of the linking portion 3022 and change the size of the loop portion 3020, as described in more detail below.

[0188] In some embodiments, the connecting portion 3022 can be received within a conduit 3034 (e.g., a flexible tube). The conduit 3034 can act as a guide for the connecting portion 3022. In some embodiments, the conduit 3034 also provides mechanical stabilization that affects how the loop portion 3020 and aperture 3014 move in response to manipulation of the connecting portion 3022. The conduit 3034 can be coupled to the housing 3032 or to another component of the system 3000 (e.g., in embodiments in which the housing 3032 is omitted).

[0189] Movement of the shuttle element 3030 can be actuated by first and second shape memory actuating elements 3028a-b. For example, the first and second shape memory actuating elements 3028a-b can each be configured to change its shape in response to a stimulus, such as heat or a mechanical load. In some embodiments, the first and second shape memory actuating elements 3028a-b are each manufactured or otherwise configured to approach (e.g., change shape, deform, transition, etc.) a relatively elongated configuration when heat is applied. In other embodiments, the first and second shape memory actuating elements 3028a-b are each manufactured or otherwise configured to approach (e.g., change shape, deform, transition, etc.) a relatively shortened configuration when heat is applied. Optionally, one shape memory actuating element can approach (e.g., change shape, deform, transition, etc.) a relatively shortened configuration when heat is applied. In some embodiments, at least one shape memory actuating element is manufactured to be relatively more thermoelastically deformable in response to a fixed force or stress at a first temperature (e.g., body temperature) than at a second temperature. The second temperature can be a temperature higher than the first temperature (eg, a temperature resulting from the application of heat to the element).

[0190] A shape change of the first and / or second shape memory actuation elements 3028a-b (e.g., due to deformation from an externally applied force, due to heating resulting in a deformation associated with a shape memory effect, etc.) can actuate movement of the shuttle element 3030 relative to the housing 3032. In some embodiments, the first and second shape memory actuation elements 3028a-b are relatively more thermoelastically deformable as described above when at an unheated temperature (e.g., at or near body temperature). In those such embodiments, actuation (e.g., expansion / elongation) of one shape memory actuation element by heating can move the shuttle element 3030 in a manner that causes the other shape memory actuation element to deform / compress.

[0191] Referring initially to FIG. 30C, in a first operational stage, the first and second shape memory actuating elements 3028a-b can exist in a neutral configuration in which both elements have been transformed from their original manufactured geometric configuration. As a result, the shuttle element 3030 can be positioned at or near the center of the housing 3032, and the loop portion 3020 can have a diameter D1. The size of the aperture (not shown) can be similar to the size of the loop portion 3020 (e.g., the aperture has a diameter the same as or similar to D1). The size of the aperture can allow a first blood flow rate through the lumen (not shown) of the shunt element.

[0192] 30D, at different stages of operation, the first shape memory actuating element 3028a has changed to a relatively shortened configuration, and the second shape memory actuating element 3028b has changed to a relatively elongated configuration. For example, the second shape memory actuating element 3028b can be heated to induce a change in shape to a longer configuration relative to its shape in the neutral position shown in FIG. 30C (e.g., toward its original manufactured geometry configuration). This shape change can apply a force to the shuttle element 3030 that moves the shuttle element along a first direction (e.g., away from the loop portion 3020). As a result, the shuttle element 3030 can apply an increased amount of tension to the connecting portion 3022 that draws the connecting portion at least partially into the housing 3032. Tension on the linking portion 3022 can cause the loop portion 3020 to tighten and / or decrease in size, decreasing the diameter D2 (e.g., by forcing a larger portion of the string element 3018 into the conduit 3034). As the loop portion 3020 decreases in size, the aperture size can also decrease (e.g., to a diameter equal to or similar to D2). As the aperture size decreases, the amount of blood flow through the lumen can decrease or be eliminated. In some embodiments, as a force is applied by the shape change of the second shape memory actuating element 3028b, the first shape memory actuating element 3028a (which is not heated and therefore can be relatively more thermoelastically deformable than when the temperature is increased) can also change shape to a relatively shortened configuration.

[0193] 30E, in a further stage of operation, the first shape memory actuating element 3028a has changed shape to a relatively elongated configuration and the second shape memory actuating element 3028b has changed shape to a relatively shortened configuration. For example, the first shape memory actuating element 3028a can be heated to induce a change in shape to a lengthened configuration (e.g., toward its original manufactured geometry configuration) relative to its shape in the neutral position shown in FIG. 30C and relative to its compressed shape shown in FIG. 30D. This shape change can apply a force to the shuttle element 3030 that moves the shuttle element along an opposing second direction (e.g., toward the loop portion 3020). As a result, the shuttle element 3030 can apply a reduced amount of tension to the connecting portion 3022 that at least partially releases the connecting portion from the housing 3032. When tension on the linking portion 3022 is reduced, the loop portion 3020 can relax and / or expand in size, increasing the diameter D3 (e.g., by allowing a larger portion of the string element 3018 to reside outside the conduit 3034). When the loop portion 3020 expands in size, the aperture size can also expand (e.g., to a diameter equal to or similar to D3). When the aperture size increases, blood flow through the lumen can increase. In some embodiments, when a force is applied by the shape change of the first shape memory actuating element 3028a, the second shape memory actuating element 3028b (which is not heated and therefore can be relatively more thermoelastically deformable than when the temperature is increased) can also change shape to a relatively shortened configuration.

[0194] It will be appreciated that the system 3000 can be configured in a number of different ways. In some embodiments, for example, the system 3000 can include multiple membrane structures and / or materials. For example, a first membrane can be connected at an interface with a first portion of the system 3000 (e.g., between the first annular element 3006a and the second annular element 3006b) and a second membrane can be connected at an interface with a second portion of the system 3000 (e.g., between the first annular element 3006a and the string element 3018). In such embodiments, the first and second membranes can be made of different materials having different material properties (e.g., flexibility, elasticity, permeability, tear strength, etc.). This approach is expected to be advantageous in embodiments where different material properties are optimal or otherwise beneficial for different regions of the system 3000. For example, in one region of the system 3000, flexibility may be an important property, and in a second region, lack of permeability may be more important than flexibility. The system 3000 can include any suitable number of membrane structures and / or materials. Optionally, some portions of the system 3000 may include multiple (eg, overlapping) membranes made from the same or different materials.

[0195] The actuation mechanism 3016 can be configured in a number of different ways. For example, in some embodiments, the first and / or second shape memory actuating elements 3028a-b can be manufactured or otherwise configured to approach a relatively shortened configuration rather than a relatively elongated configuration upon heating. As a result, applying heat to the first shape memory actuating element 3028a can draw more of the string elements 3018 into the housing 3032, and applying heat to the second shape memory actuating element 3028b can release more of the string elements 3018 from the housing 3032. Additionally, although FIGS. 30C-30E depict the first and second shape memory actuating elements 3028a-b as having a folded or zigzag shape, in other embodiments, the first and second shape memory actuating elements 3028a-b can have different shapes, such as a serpentine shape, a curved shape, a bent shape, or a coiled shape.

[0196] In some embodiments, the first and second shape memory actuating elements 3028a-b are positioned on the same side of the shuttle element 3030. In such embodiments, one shape memory actuating element can be fabricated to move toward a relatively elongated / expanded configuration when heated, and the second shape memory actuating element can be fabricated to move toward a relatively shortened / contracted configuration when heated. In other embodiments, any number of shape memory actuating elements fabricated to have similar or dissimilar original geometric configurations may be utilized.

[0197] In some embodiments, the string element 3018 itself functions as the actuation mechanism. In those embodiments, any additional actuation mechanism (e.g., actuation mechanism 3016) may be omitted. For example, one embodiment may consist of the string element 3018, which is composed entirely of the loop portion 3020 (e.g., lacking the connecting portion 3022) that interfaces with the opening or hole 3024 (e.g., eyelet). The loop portion 3020 may also directly or indirectly interface with the membrane 3012 to form the aperture 3014. The string element 3018 may include a shape memory material (e.g., Nitinol wire or struts). In an operating mode, the size and / or shape of the loop portion 3020 may change, thereby changing the shape of the aperture 3014. For example, the shape memory material that includes the loop portion 3020 may be manufactured to have a relatively small geometry (e.g., small diameter). Before or after implantation, a force (e.g., a radially outward force provided by inflating a balloon) can be applied to the loop portion 3020 to transform it into a configuration having a relatively large geometry. Heat can then be applied to the shape memory loop portion 3020 to induce a shape change toward the relatively small manufactured geometry of the shape memory loop portion. A series of similar operations can be performed over a period of time to allow the care provider to change the aperture size multiple times within the range of possible sizes. In other embodiments, the shape memory material comprising the loop portion 3020 can be manufactured to have a relatively large geometry. Before or after implantation, a force (e.g., a compressive force from a snare tool) can be applied to the loop portion 3020 to transform it into a configuration having a relatively small geometry. Heat can then be applied to the shape memory loop portion to induce a shape change toward the relatively large manufactured geometry of the shape memory loop portion.

[0198] In some embodiments, the string element 3018 includes two or more shape memory elements that are mechanically coupled together (e.g., welded, sewn, glue / adhesive, rivet / crimp, etc.) in such a way that the two or more elements are electrically and / or thermally insulated from one another. In such embodiments, for example, a first shape memory element may be manufactured with a relatively large geometry and a second shape memory element may be manufactured with a relatively small geometry. When the elements are mechanically coupled, a similar motion can be driven in the non-heated element by thermally driving actuation of one element toward its original geometric configuration, since the non-heated element remains in a relatively more thermoelastically deformable material phase. Thus, the size of the loop portion 3020, and therefore the size of the aperture 3014, can be adjusted to be larger as well as smaller using energy provided to different portions of the string element 3018. In such embodiments, the size of the loop portion 3020 can also be changed by applying an external force (e.g., by an inflatable balloon).

[0199] In embodiments of the present technology that utilize heat or another form of energy applied to the shape memory element, or another component of the system, the energy / heat can be applied both invasively (e.g., via a catheter delivering a laser, radio frequency, or another form of energy, via an internal stored energy source such as a supercapacitor, etc.), non-invasively (e.g., using radio frequency energy delivered by a transmitter outside the body, focused ultrasound, etc.), or by a combination of these methods.

[0200] 31A and 31B show a portion of an inter-atrial shunt system 3100 configured in accordance with another embodiment of the present technology. More specifically, FIG. 31A is an enlarged perspective view of a portion of the system 3100, and FIG. 31B is an enlarged perspective view of an actuation mechanism 3101 and a cross-sectional view of an adjustable structure 3102 of the system 3100. Components of the system 3100 can be implemented or combined with any of the other embodiments disclosed herein, such as the system 3000 described with respect to FIGS. 30A-30E.

[0201] Referring initially to FIG. 31A, the system 3100 includes an actuation mechanism 3101 coupled to an adjustable structure 3102. The adjustable structure 3102 can be operatively coupled to a membrane (e.g., membrane 3012 in FIGS. 30A-30B, omitted for clarity) and an aperture 3104. The aperture 3104 can at least partially overlap a lumen of a shunt element (not shown) and affect a fluid flow rate therethrough, as described above with respect to aperture 3014 in FIGS. 30A-30E. In the illustrated embodiment, the adjustable structure 3102 is a band, ring, or other annular structure that forms a perimeter of the aperture 3104. The adjustable structure 3102 can be coupled to the portion of the membrane surrounding the aperture 3104 using fasteners, adhesives, sutures, or any other suitable technique known to one of skill in the art.

[0202] The adjustable structure 3102 can be made from a flexible and / or relatively malleable material (e.g., a metal or polymer) that can be configured to flex and / or deform (e.g., elastically and / or plastically deform) when a force is applied thereto. In one particular example, the adjustable structure 3102 can be an annealed stainless steel wire. As another particular example, the adjustable structure 3102 can be a polyurethane string or suture. As a result, when a force is applied to the adjustable structure 3102 (e.g., by the actuation mechanism 3101), the geometry (e.g., size and / or shape) of the adjustable structure 3102 can change, resulting in a corresponding change in the geometry of the aperture 3104. For example, as the size (e.g., diameter) of the adjustable structure 3102 decreases, the portion of the membrane surrounding the aperture 3104 can be tightened, stretched, loosened, or otherwise drawn apart by the adjustable structure 3102, causing the aperture 3104 to decrease in size. Conversely, as the size of the adjustable structure 3102 increases, the portion of the membrane surrounding the aperture 3104 can be released, loosened, stretched, or otherwise drawn apart, causing the aperture 3104 to increase in size. In some embodiments, the adjustable structure 3102 is transitionable between a number of different configurations having different geometries, such as an expanded configuration having a relatively large size (e.g., as measured by diameter, cross-sectional area), and / or a compressed configuration having a relatively small size. When the adjustable structure 3102 is in the expanded configuration, the aperture 3104 can provide a relatively low resistance to the flow of fluid therethrough, thereby allowing a high flow rate of fluid. When the adjustable structure 3102 is in a compressed configuration, the apertures 3104 can provide a relatively high resistance to the flow of fluid therethrough, thereby partially or completely restricting the flow of fluid.

[0203] Optionally, the adjustable structure 3102 can be made from a shape memory material such as Nitinol. In such embodiments, for example, a change in size and / or geometry of the adjustable structure 3102 (and thus the aperture 3104) can be induced by applying an external stress to the adjustable structure 3102 and / or inducing an internal stress within the adjustable structure 3102 by applying energy (e.g., heating the adjustable structure 3102 above a transition temperature results in at least a temporary change in material state).

[0204] The actuation mechanism 3101 can be configured to selectively change the geometry of the adjustable structure 3102 to adjust the size of the aperture 3104 and therefore the relative flow rate of fluid therethrough. In some embodiments, the actuation mechanism 3101 is coupled to the adjustable structure 3102 via a lever element 3106. The lever element 3106 can be any elongated structure (e.g., strut, bar, rod, tube, etc.) and can be configured to transmit the force and / or motion applied to the adjustable structure 3102 by the actuation mechanism 3101. The lever element 3106 can be made from a superelastic material (e.g., Nitinol) or another suitable material (e.g., stainless steel, cobalt chrome, polymer, etc.). Optionally, the lever element 3106 can be made from a non-shape memory material. In other embodiments, the lever element 3106 can be made from a shape memory material, but the shape memory properties of the material are not used during actuation of the lever element 3106 (e.g., the lever element 3106 is not heated during actuation).

[0205] In some embodiments, the lever element 3106 includes a first end 3108a coupled to the actuation mechanism 3101 and a second end 3108b coupled to the adjustable structure 3102. The first end 3108a can be pivotally coupled to the actuation mechanism 3101 such that the lever element 3106 can pivot or otherwise rotate relative to the actuation mechanism 3101. The second end 3108b can be pivotally coupled to the adjustable structure 3102 such that the lever element 3106 can pivot or otherwise rotate relative to the adjustable structure 3102. The pivot coupling(s) can be implemented in a variety of ways known to those skilled in the art. For example, the first and / or second ends 3108a-b can be pivotally coupled using hinges or other rotating fasteners. As another example, the first and / or second ends 3108a-b can be configured to flex, such as by reducing the thickness and / or stiffness of these portions compared to other portions of the lever element 3106.

[0206] In some embodiments, the actuation mechanism 3101 is configured to change the geometry of the adjustable structure 3102 by pivoting the lever element 3106 (e.g., relative to the adjustable structure 3102 and / or the actuation mechanism 3101). For example, pivoting the lever element 3106 in a first direction D1 can apply an outward force and / or a tensile force to the adjustable structure 3102, expanding its size. Pivoting the lever element 3106 in an opposing second direction D2 can apply an inward force and / or a compressive force to the adjustable structure 3102, decreasing its size. In other embodiments, pivoting the lever element 3106 in one direction (e.g., D1 or D2) can release a force applied to the adjustable structure 3102 by pivoting the lever element 3106 in the opposing direction. Additional features of the actuation mechanism 3101 are described in more detail below.

[0207] The adjustable structure 3102 can be coupled to one or more struts 3110, which connect the adjustable structure 3102 to a shunt element (not shown). The struts 3110 can be made of a superelastic material (e.g., Nitinol) or another suitable material (e.g., stainless steel, cobalt chrome, polymer, etc.). Each strut can include a first end 3112a that is coupled to the adjustable structure 3102 and a second end 3112b that is coupled to the shunt element or to another portion of the system 3100. The struts 3110 can be arranged radially around the perimeter (e.g., circumference) of the adjustable structure 3102 in a spoke-like configuration. The struts 3110 can be configured to limit the extent to which the adjustable structure 3102 can move relative to the shunt element (e.g., along the longitudinal axis of the shunt element). As a result, when the lever element 3106 applies or releases a force to the adjustable structure 3102, the adjustable structure 3102 can expand or contract radially in a plane (e.g., a plane that includes or is parallel to the aperture 3104) rather than moving longitudinally (e.g., along the longitudinal axis of the shunt element). In some embodiments, the first and second ends 3112a-b of each strut 3110 are pivotally coupled to the adjustable structure 3102 and the shunt element, respectively, such that each strut 3110 pivots (e.g., relative to the adjustable structure 3102 and / or the shunt element) as the geometry of the adjustable structure 3102 changes. The pivot couplings of the struts 3110 can be implemented as hinges, bendable regions, or any other suitable structure known to one of skill in the art. Although FIG. 31A shows ten struts 3110, in other embodiments, the system 3100 can include a different number of struts (eg, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 15, or 20 struts).

[0208] In some embodiments, the adjustable structure 3102 can be coupled to one or more structural members 3114. The structural members 3114 can be arranged radially around the adjustable structure 3102 in a spoke-like configuration. In the illustrate...

Claims

1. An adjustable interatrial shunt for fluidly connecting a left atrium and a right atrium of a patient's heart across a septal wall of the patient, the adjustable interatrial shunt comprising: A first portion; and a second portion coupled to the first portion; a lumen extending at least partially through the first portion and / or the second portion, the lumen configured to fluidly couple the left atrium and the right atrium; Equipped with the first portion has a superelastic material state at body temperature, and is configured to automatically expand when the first portion is deployed from a delivery catheter; An adjustable inter-atrial shunt, wherein the second portion has a shape memory state at body temperature, and in response to the second portion being heated above a transition temperature above body temperature, the second portion transitions in shape and / or size, changing the resistance to flow through the lumen.

2. An adjustable inter-atrial shunt as described in claim 1, wherein the first portion and the second portion have a unitary structure.

3. An adjustable inter-atrial shunt as described in claim 1, wherein the first portion has a cylindrical or annular shape and the second portion has a funnel or truncated cone shape.

4. An adjustable inter-atrial shunt as described in claim 3, wherein the second portion includes a first end coupled to the first portion and a second end extending away from the first portion.

5. An adjustable inter-atrial shunt as described in claim 1, wherein the lumen and the first portion and the second portion have a common central axis.

6. An adjustable interatrial shunt as described in claim 1, wherein the first portion is sized and shaped to reside within an opening in the septal wall.

7. An adjustable inter-atrial shunt as described in claim 6, wherein the first portion is configured to stabilize the adjustable inter-atrial shunt within the opening across the septal wall.

8. An adjustable inter-atrial shunt as described in claim 1, wherein the first portion and / or the second portion at least partially define the lumen.

9. An adjustable inter-atrial shunt as described in claim 1, further comprising a membrane, the membrane at least partially defining the lumen.

10. The adjustable interatrial shunt of claim 1, wherein the first portion and the second portion are at least partially constructed from nitinol.

11. An adjustable shunt for fluidly coupling a first body region and a second body region of a patient, the adjustable shunt comprising: A first portion; and a second portion coupled to the first portion; a lumen extending at least partially through the first portion and / or the second portion, the lumen configured to fluidly couple the first body region and the second body region; Equipped with the first portion has a superelastic material state at body temperature, and is configured to automatically expand when the first portion is deployed from a delivery catheter; the second portion has a shape memory state at body temperature, and in response to the second portion being heated above a transition temperature above body temperature, the second portion transitions in shape and / or size to change the resistance to flow through the lumen; An adjustable shunt, wherein the lumen and the first and second portions have a common central axis.

12. An adjustable shunt as described in claim 11, wherein the second portion extends away from the first portion.

13. An adjustable shunt as described in claim 11, wherein the second portion is positioned at least partially within the first portion.

14. An adjustable shunt as described in claim 11, wherein the first portion has a cylindrical or annular shape and the second portion has a funnel or truncated cone shape.

15. The adjustable shunt of claim 11, wherein the first portion and the second portion have a unitary structure.

16. The adjustable shunt of claim 11, wherein the first portion and the second portion are at least partially constructed from Nitinol.

17. An adjustable shunt for fluidly coupling a first body region and a second body region of a patient, the adjustable shunt comprising: A first portion; and a second portion coupled to the first portion; a lumen extending at least partially through the first portion and / or the second portion, the lumen configured to fluidly couple the first body region and the second body region; Equipped with the first portion has a superelastic material state at body temperature, and is configured to automatically expand when the first portion is deployed from a delivery catheter; the second portion has a shape memory state at body temperature, and in response to the second portion being heated above a transition temperature above body temperature, the second portion transitions in shape and / or size to change the resistance to flow through the lumen; An adjustable shunt, wherein the first portion has a cylindrical or annular shape and the second portion has a funnel or frusto-conical shape.

18. An adjustable shunt as described in claim 17, wherein the second portion includes a first end coupled to the first portion and a second end extending away from the first portion.

19. An adjustable shunt as described in claim 17, wherein the second portion is positioned at least partially within the first portion.

20. An adjustable shunt as described in claim 17, wherein the first portion is sized and shaped to stabilize the adjustable shunt across patient tissue between the first body region and the second body region.

Images