Respiration driven caval obstruction devices and methods

A method of regulating blood flow in a patient, the method comprising:

• implanting a compressible bladder within a body cavity of a patient such that the compressible bladder is exposed to cyclical pressure changes within the cavity during inhalation and exhalation, wherein the body cavity is a thoracic cavity or an abdominal cavity;
• implanting an occluding device within a blood vessel, the occluding device including an expandable member, wherein the blood vessel is a superior vena cava or an interior vena cava;
• fluidly or mechanically coupling the compressible bladder to the expandable member;
• and
• allowing the cyclical pressure changes within the body cavity to actuate the compressible bladder, which in turn actuates the expandable member to modulate blood flow through the blood vessel.

A method of modulating venous blood flow in a patient, the method comprising:

• implanting a compressible bladder within a thoracic cavity of the patient such that the compressible bladder is exposed to pressure changes in the thoracic cavity caused by respiration;
• implanting an occluding device within a lumen of a vena cava of the patient, the vena cava comprising a superior vena cava or an inferior vena cava, the occluding device comprising a stent and an expandable member disposed within the stent, wherein the implanting the occluding device comprises anchoring the stent against an inner surface of the vena cava;
• fluidly coupling the compressible bladder to the expandable member through a closed fluid pathway containing an inflation fluid;
• and
• allowing respiratory-induced increases in pressure in the thoracic cavity to compress the compressible bladder and drive the inflation fluid into the expandable member to increase occlusion of the vena cava, and allowing respiratory-induced decreases in pressure in the thoracic cavity to permit decompression of the compressible bladder and withdrawal of the inflation fluid from the expandable member to decrease occlusion of the vena cava,
• thereby cyclically modulating venous blood flow through the superior vena cava or the inferior vena cava in response to pressure changes in the thoracic cavity caused by respiration.