Effects of intraluminal and extracorporeal inferior vena caval bypass on canine hemodynamics

Objective: To compare inferior vena cave-right atrial extracorporeal bypass with intraluminal atriocaval shunting during hepatic vascular isolation. Design: Prospective, randomized, controlled animal study. Setting: 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 shunting, 20- and 24-Fr intraluminal shunts were inserted into the inferior vena cava via right atriotomy. For extracorporeal bypass, each animal underwent inferior vena cave, portal vein, and right atrial cannulation for venovenous bypass, utilizing a centrifugal pump. Hemodynamic data were recorded at baseline and at intervals after caval occlusion, Pringle maneuver, and caval occlusion with Pringle maneuver. Measurements and Main Results: Isolated Pringle maneuver and caval occlusion with Pringle maneuver produced significant reductions in mean arterial pressure (MAP) and cardiac output, irrespective of pulmonary artery occlusion pressure. Extracorporeal bypass, including both caval end portal venous return, produced significant increases in MAP and cardiac output during caval occlusion with Pringle maneuver, while atriocaval shunting and extracorporeal bypass without portal venous return did not improve MAP or cardiac output. Conclusion: Venovenous extracorporeal bypass with portal return, acting as a right ventricular assist device, is superior to intraluminal atriocaval shunting in maintaining hemodynamic stability during hepatic vascular isolation.