Methods are provided for effectively distinguishing the abilities of a human liver and an extracorporeal liver in an extracorporeal liver perfusion system to extract cholate and, thus, measure relative liver function.

Vascular blood flow modulation is disclosed using metallic compliance-enhancement devices that contain a sealed volume of fluid. The device includes a first elongated inflatable nitinol balloon and a second elongated inflatable nitinol balloon, each having an outer sealed terminus and an inner open fluid port, and a nitinol connector tube that fluidly couples the balloons and has a diameter smaller than the inflated diameters of the balloons. The first balloon is positioned within an arterial vessel and the second balloon is positioned within a venous vessel, with the connector tube spanning between the vessels. During systole, arterial pressure compresses the first balloon to drive fluid through the connector tube into the second balloon, thereby expanding the second balloon and increasing venous blood flow. Cyclic systolic and diastolic pressure variations cause fluid to shuttle between the balloons, producing a compliance-enhancing effect.

Vascular blood flow modulation is disclosed using metallic compliance-enhancement devices that contain a sealed volume of fluid. The device includes a first elongated inflatable nitinol balloon and a second elongated inflatable nitinol balloon, each having an outer sealed terminus and an inner open fluid port, and a nitinol connector tube that fluidly couples the balloons and has a diameter smaller than the inflated diameters of the balloons. The first balloon is positioned within an arterial vessel and the second balloon is positioned within a venous vessel, with the connector tube spanning between the vessels. During systole, arterial pressure compresses the first balloon to drive fluid through the connector tube into the second balloon, thereby expanding the second balloon and increasing venous blood flow. Cyclic systolic and diastolic pressure variations cause fluid to shuttle between the balloons, producing a compliance-enhancing effect.