Association between the donor to recipient ICG-PDR variation rate and the functional recovery of the graft after orthotopic liver transplantation: A case series

Use of Fluorescence Imaging in Liver Transplant Surgery

Liver transplant surgery is a complex procedure that demands high knowledge of surgical anatomy and the precise recognition and preservation of structures. To address this, the use of fluorescence imaging has facilitated the identification of anatomical structures such as biliary ducts, arteries, and liver segmentation. Indocyanine green is among the most commonly utilized fluorescent agents, not just during surgery but also in the pre- and postoperative phases, where it is used to assess graft failure by measuring the plasma disappearance rate. New advancements such as artificial intelligence paired with fluorescence imaging have the potential to enhance patient outcomes. Additionally, technologies such as augmented reality and mixed reality could be integrated into surgical procedures, broadening the scope of possibilities for improving patient safety.

ICG-mediated fluorescence-assisted debridement to promote wound healing

The purpose of this study was to examine the efficacy of ICG-mediated fluorescence molecular imaging (FMI) in debridement of necrotic tissue. 96 wound-infected rats were randomly divided into control group, ICG group, excitation light (EL)group and FMI group for debridement of necrotic tissue (n = 24). (I) Control group: only debridement; (II) ICG group: ICG injection before debridement; (III) EL group: Debridement under EL; (IV) FMI group: Debridement guided by ICG-mediated FMI. On the 3rd, 6th, and 9th days, the wound tissues of the rats in each group were collected for histological examination, and the levels of serum interleukin-4 (IL-4) and interferon-γ (INF-γ) were analyzed. The wound healing rate, wound score and body weight of the rats in each group were followed up until the wound healed. The results showed that the infected wounds of the rats in the FMI group had significant fluorescence development. The level of serum IL-4 in the FMI group was higher than that in the other three groups on the 6th day (p<0.01), while the level of INF-γ was lower than that in the other three groups on the 6th and 9th day (p<0.05). The results of dynamic wound tissue H&E staining indicated that the wound healing in the FMI group was better than the other three groups. The in vivo follow-up results showed that the wound healing rate and wound score of the FMI group were better than the other three groups, and the growth of rats had no difference with the other groups. ICG-mediated FMI can achieve accurate imaging of necrotic tissue for debridement, and so can accelerate wound healing, which has good clinical application prospects.

Indocyanine green clearance test in liver transplantation: defining cut-off levels for graft viability assessment during organ retrieval and for the prediction of post-transplant graft function recovery - the Liver Indocyanine Green (LivInG) Trial Study Protocol

INTRODUCTION

Viability assessment of the graft is essential to lower the risk of liver transplantation (LT) failure and need for emergency retransplantation, however, this still relies mainly on surgeon's experience. Post-LT graft function recovery assessment is also essential to aid physicians in the management of LT recipients and guide them through challenging decision making.This study aims to trial the use of indocyanine green clearance test (IGT) in the donor as an objective tool to assess graft viability and in the recipient to assess graft function recovery after LT.

METHODS AND ANALYSIS

This is an observational prospective single-centre study on consecutive liver transplant donors and recipients.

PRIMARY OBJECTIVE

To determine the capability of IGT of predicting graft viability at the time of organ retrieval. Indocyanine green will be administered to the donor and the plasma disappearance rate (PDR) measured using the pulsidensitometric method. Some 162 IGT donor procedures will be required (α, 5%; β, 20%) using an IGT-PDR cut-off value of 13% to achieve a significant discrimination between viable and non-viable grafts.

SECONDARY OBJECTIVE

IGT-PDR will be measured at different time-points in the LT recipient: during the anhepatic phase, after graft reperfusion, at 24 hours, on day 3 and day 7 after LT. The slope of IGT values from the donor to the recipient will be evaluated for correlation with the development of early allograft dysfunction.

ETHICS AND DISSEMINATION

This research protocol was approved by Fondazione Policlinico Universitario Agostino Gemelli IRCCS Ethics Committee (reference number: 0048466/20, study ID: 3656) and by the Italian National Transplant Center (CNT) (reference number: Prot.11/CNT2021). Liver recipients will be required to provide written informed consent. Results will be published in international peer-reviewed scientific journals and presented in congresses.

TRIAL REGISTRATION NUMBER

NCT05228587.