Chapter 53: Specific Considerations for Organ Preservation Techniques

INTRODUCTION

Liver transplantation is dependent on preservation techniques that maintain the viability of explanted organs until their revascularization in the recipient.

PRESERVATION INJURY

During the process of brain death, organ procurement and preservation liver grafts are submitted to injurious insults that are collectively referred to as preservation injury:

• Pre-preservation injury

• Cold preservation injury

• Rewarming injury

• Reperfusion injury

Liver grafts from non-heart-beating donors (donation after cardiac death [DCD]) experience an additional warm ischemia injury between cardiac death and cold flushing at procurement.

Preservation injury increases:

• Primary graft nonfunction and primary dysfunction

• Graft rejection

• Morbidity

• Discarding of liver grafts due to outcome concerns

The current standard technique of liver preservation is static cold preservation using hypothermia and special preservation solutions.

STATIC COLD PRESERVATION

The main principle of static cold preservation is the reduction of the core temperature of the liver to 4°C, which diminishes enzyme activity and reduces the metabolism to approximately 10% in the majority of cells. Nevertheless, during cold preservation, cellular homeostasis is lost. Major alterations occur in electrolytes, pH, intracellular enzymes and proteins, and intracellular water. Preservation solutions are therefore composed to counteract these processes.

The main ingredients of the preservative solutions in use today are electrolytes, colloids, buffers, and antioxidants (Table 53-1). These components are added to minimize cellular edema, acidosis, and production of reactive oxygen species (ROS) after reperfusion. Nutritional substrates are usually added to provide the energy requirement for the synthesis of adenosine triphosphate (ATP).