Cold ischemia time in liver transplantation: An overview

Abstract

The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold ischemia time (CIT). This simple definition reveals a multifactorial time frame that depends on donor hepatectomy time, transit time, and recipient surgery time, and is one of the most important donor-related risk factors which may influence the graft and recipient's survival. Recently, the growing demand for the use of marginal liver grafts has prompted scientific exploration to analyze ischemia time factors and develop different organ preservation strategies. This review details the CIT definition and analyzes its different factors. It also explores the most recent strategies developed to implement each timestamp of CIT and to protect the graft from ischemic injury.

Keywords: Cold ischemia time; Donation after cardiac death; Liver transplantation; Machine perfusion; Organ donation; Warm ischemia time.

Figure 1

The different phases during liver procurement and transplantation. In donation after brain death donor, warm ischemia time (WIT) is very short, and it starts at the time of cross clamping until flush of cold perfusion. Donation after circulatory death donor is more complex: WIT starts when either SpO₂ or blood pressure drop below a certain threshold and lasts until the start of cold perfusion or the start of normothermic regional perfusion. For every donor, cold ischemia time (CIT) starts at cold perfusion, after aortic cross-clamp, and continues during graft removal, graft transportation and back table preparation until removal from ice for implantation in the recipient. Transport time is a part of CIT unless the organ undergoes some form of normothermic organ perfusion. CIT: Cold ischemia time; DBD: Donation after brain death; DCD: Donation after circulatory death.