Would routine avoidance of veno-veno bypass be possible during liver transplantation?

Abstract

CC Primary failure of the liver is associated with the secondary dysfunction of virtually all other organ systems, including the cardiovascular, pulmonary, renal, and central nervous systems. Furthermore, liver transplantation is a major surgical procedure with accompanying life-threatening hemorrhage, massive transfusion, and shifts in body fluids. Such patients suffer from additional insult caused by clamping of the great vessels, including the inferior vena cava (IVC) and portal vein (PV) during the anhepatic stage. As a result, additional circulatory insufficiency to organs including the kidney, and acidosis, hypoxia, intestinal edema, and changes in gut mucosal capillary permeability may occur. To reduce these non-physiologic insults resulting from the clamping of great vessels, veno-veno bypass (VVB) has been used during the anhepatic stage. This technique involves cannulating the inferior vena cava and the portal vein, and diverting their blood flow away from the liver and back to the right heart, usually via an axillary vein or a subclavian vein. By doing so, decompression of the portal circulation, and a reduction of congestion in the lower extremities and splanchnic circulation can be achieved. However, the use of VVB has its own adverse effects, such as accidental decannulation, circuit clots, embolic events, prolongation of operation time, vessel injury, and coagulopathy [1]. Massive pulmonary thromboembolism resulting in fatal right heart failure, and congestion of the transplant liver has been reported [2]. Several studies have reported no clear advantage for the routine use of VVB in liver transplantation surgery [3,4]. Furthermore, the piggyback technique, which just tangentially clamps the recipient’s suprarenal caval segment, is becoming widely used for liver transplantation surgery and allows the hemodynamic disturbances during anhepatic stage to be minimised [5]. Accordingly, the regularity of use of VVB appears to vary across institutions. Although some centers never use the technique at all, and all surgeries are performed by using a piggyback technique with no complete clamping of the IVC, many use VVB in selected cases; others use the technique on every case routinely, the exception being small