Vena caval occlusion

An apparatus, comprising:

• an occlusion element configured to reduce cardiac preload of a subject by being placed in a vena cava of the subject at an infra-renal location, and to partially occlude the subject's vena cava at the infra-renal location;
• one or more sensors configured to monitor one or more physiological parameters of the subject selected from the group consisting of:
• lower body venous pressure, central venous pressure, central venous blood flow, renal venous pressure, cardiac diameter, cardiac volume, arterial pressure, and arterial blood flow;
• a computer processor configured to modulate an extent to which the occlusion element occludes the vena cava at the infra-renal location, responsively to the one or more physiological parameters;
• and
• a blood pump configured to be placed at a location within the vena cava that is downstream of junctions of the vena cava with all renal veins of the subject, the blood pump being configured to reduce the subject's renal venous pressure relative to the subject's central venous pressure by pumping blood in an antegrade direction through the vena cava from the location, and
• wherein the computer processor is further configured to modulate the rate at which the blood pump pumps blood in the antegrade direction responsively to the one or more physiological parameters in coordination with modulating the extent to which the vena cava is occluded at the infra-renal location responsively to the one or more physiological parameters, so as to:
• maintain a first ratio between the subject's renal venous pressure and the subject's lower body venous pressure, and
• maintain a second ratio between the subject's central venous pressure and the subject's lower body venous pressure,
• the second ratio being different from the first ratio.