A technical modification to improve experimental production of hepatogenic ascites.

Constriction of the thoracic inferior vena cava is a useful experimental maneuver to reproduce massive ascites. Unfortunately, the margin of safety of this technique is narrow in that too much constriction overly restricts venous return with subsequent shock and death, and lesser constriction is often associated with extensive venous collateralization via the azygos system and failure to sustain hepatic congestion. By combining azygos vein ligation with 50% constriction of the supradiaphragmatic inferior vena caval circumference at the time of the initial thoracotomy, we have found that intense hepatic congestion is sustained and that dogs consistently develop massive ascites within 2-3 weeks.