Adjustable interatrial shunts and associated systems and methods

A system for shunting blood between a left atrium and a right atrium of a patient, the system comprising:

• a flow path extending between the left atrium and the right atrium;
• an expandable flow control element positioned proximate and/or within the flow path, wherein the expandable flow control element is transitionable between a first geometry imparting a first flow resistance through the flow path and a second geometry imparting a second flow resistance through the flow path that is different than the first flow resistance;
• and
• a fluid reservoir coupled to the expandable flow control element and spaced apart from the flow path,
• wherein the system is configured to (i) transfer fluid from the fluid reservoir toward the expandable flow control element to transition the expandable flow control element from the first geometry toward the second geometry, and (ii) transfer fluid from the expandable flow control element to the fluid reservoir to transition the expandable flow control element from the second geometry toward the first geometry.

A system for shunting blood between a left atrium and a right atrium of a patient, the system comprising:

• a frame having a generally fixed outer diameter and configured to engage a septal wall of the patient when the system is implanted in the patient;
• and
• a toroid-shaped expandable member positioned within the frame, the toroid-shaped expandable member having a lumen extending therethrough, wherein, when implanted within the patient, the lumen is configured to fluidly connect the left atrium and the right atrium of the patient,
• wherein increasing a volume of the toroid-shaped expandable member decreases a cross-sectional area of the lumen, and
• wherein decreasing a volume of the toroid-shaped expandable member increases a cross-sectional area of the lumen.

An adjustable shunt system for moving blood between a left atrium and a right atrium of a patient, the adjustable shunt system comprising:

• an external surface facing radially outward, wherein the external surface has a generally fixed diameter;
• an internal surface facing radially inward, wherein the internal surface defines a lumen extending through the adjustable shunt, wherein, wherein the shunt system is implanted in the patient, the lumen is configured to fluidly couple the left atrium and the right atrium;
• and
• a flow control element configured to change a shape and/or size of the internal surface to adjust a cross-sectional area of the lumen.