Chapter 52: Machine Preservation of Liver Grafts

INTRODUCTION

Liver transplantation is the only treatment option for patients with end-stage liver disease. However, the number of waiting list candidates exceeds by far the number of available grafts. Therefore, the use of marginal grafts has emerged as a very useful tool to increase the donor pool. These extended-criteria organs include grafts donated after circulatory death (DCD), steatotic livers, livers from elderly donors, and grafts with prolonged cold storage time. Unfortunately, extended-criteria grafts are more susceptible to ischemic injury during cold static storage and are more likely to develop graft dysfunction and biliary complications after transplantation.¹ In addition, cold static storage does not allow the assessment of organs during the preservation period and moreover does not allow the application of protective strategies. Currently, the decision to accept or decline a liver graft is mainly based on personal opinion rather than objective data. The shortcomings of cold static storage and advances in perfusion technology have resulted in an increased interest in normothermic perfused organ preservation as an alternative to cold static storage.^1–3

In this chapter we provide the reader with a comprehensive overview of the technical aspects of machine preservation of liver grafts.

TRICKS AND TIPS

Warm ex vivo perfusion consists of dual oxygenated perfusion of the liver through both the hepatic artery and portal vein.⁴ The perfusate is drained from the liver through the vena cava, constituting a closed circuit (Fig. 52-1).

Perfusion Setup

• The hepatic artery is set at a pressure of 60 mm Hg, resulting in a flow of 200 mL/min to 400 mL/min.

• Portal vein pressures are adjusted between 2 and 4 mmHg, generating a flow of 900 to 1100 mL/min.

Perfusate Composition

• Albumin-based solution that provides oncotic pressure to the perfusate

• Red blood cells that act as oxygen carriers

• O₂

• Nutrition

• Vasodilator

BACK TABLE PREPARATION

• Remove the gallbladder in situ and cauterize bleeders from the gallbladder bed before flushing the liver with preservation solution (this will minimize bleeding during the perfusion period).

• After retrieving the liver from the donor, place it in a bowl full of ice covered with an organ bag and prepare for a complete back table at the donor hospital.

• Start the back table by dissecting the vena cava, clearing it off the diaphragm (Fig. 52-2). Tie all branches and test for leakage.

• Dissect the portal vein up to its bifurcation into right and left, tie all small branches, and test for leakage.

• Create a patch of aorta in the celiac axis and dissect the common hepatic artery until the GDA. Tie all branches (including left gastric and splenic artery) and test ...