EFFECTS OF INTRALUMINAL AND EXTRACORPOREAL INFERIOR VENA-CAVAL BYPASSON CANINE HEMODYNAMICS

Objective: To compare inferior vena cava-right atrial extracorporeal b ypass with intraluminal atriocaval shunting during hepatic Vascular is olation. Design: Prospective, randomized, controlled animal study. Set ting: University research laboratory. Subjects: Adult mongrel dogs (n = 5) weighing 20 to 27 kg. Interventions: Anesthetized dogs underwent laparotomy and sternotomy for vascular isolation. For atriocaval shunt ing, 20- and 24-Fr intraluminal shunts were inserted into the inferior Vena cava via right atriotomy. For extracorporeal bypass, each animal underwent inferior vena cava, portal vein, and right atrial cannulati on for venovenous bypass, utilizing a centrifugal pump. Hemodynamic da ta were recorded at baseline and at intervals after caval occlusion, P ringle maneuver, and caval occlusion with Pringle maneuver. Measuremen ts and Main Results: Isolated Pringle maneuver and caval occlusion wit h Pringle maneuver produced significant reductions in mean arterial pr essure (MAP) and cardiac output, irrespective of pulmonary artery occl usion pressure. Extracorporeal bypass, including both caval and portal venous return, produced significant increases in MAP and cardiac outp ut during caval occlusion with Pringle maneuver, while atriocaval shun ting and extracorporeal bypass without portal venous return did not im prove MAP or cardiac output. Conclusion: Venovenous extracorporeal byp ass with portal return, acting as a right ventricular assist device, i s superior to intraluminal atriocaval shunting in maintaining hemodyna mic stability during hepatic vascular isolation.