Return of the cold: How hypothermic oxygenated machine perfusion is changing liver transplantation

Hypothermic Oxygenated machine PErfusion (HOPE) has recently emerged as a preservation technique which can reduce ischemic injury and improve clinical outcomes following liver transplantation. First developed with the advent solid organ transplantation techniques, hypothermic machine perfusion largely fell out of favour following the development of preservation solutions which can satisfactorily preserve grafts using the cheap and simple method, static cold storage (SCS). However, with an increasing need to develop techniques to reduce graft injury and better utilise marginal and donation after circulatory death (DCD) grafts, HOPE has emerged as a relatively simple and safe technique to optimise clinical outcomes following liver transplantation. Perfusing the graft with cold, acellular, oxygenated perfusate either via the portal vein (PV) alone, or via both the PV and hepatic artery (HA), HOPE is generally commenced for a period of 1-2 h immediately prior to implantation. The technique has been validated by multiple randomised control trials, and pre-clinical evidence suggests HOPE primarily reduces graft injury by decreasing the accumulation of harmful mitochondrial intermediates, and subsequently, the severity of post-reperfusion injury. HOPE can also facilitate real time graft assessment, most notably via the measurement of flavin mononucleotide (FMN) in the perfusate, allowing transplant teams to make better informed clinical decisions prior to transplantation. HOPE may also provide a platform to administer novel therapeutic agents to ex situ organs without risk of systemic side effects. As such, HOPE is uniquely positioned to revolutionise how liver transplantation is approached and facilitate optimised clinical outcomes for liver transplant recipients.

Impact of geographical health disparities on outcomes following pelvic exenteration at a centralised quaternary referral centre

INTRODUCTION

Pelvic exenteration (PE) is an ultra-radical procedure performed for primary or recurrent malignancies confined to the pelvis. Health outcomes for rural Australian populations are generally inferior compared to those from metropolitan centres, however, the effect of geographical location on outcomes following PE is poorly defined. The aim of this study was to investigate how geographical location affects oncological, quality of life (QoL) and survival outcomes following PE.

METHODS

Consecutive patients undergoing PE between 1994 and 2022 at a single centre were included. Patient post codes were linked with the Australian Statistical Geography Standard Remoteness Structure to stratify patients into five groups based on the geographical location of their residence. Primary outcome measures included patient survival, QoL and oncological outcomes.

RESULTS

A total of 953 patients were included, of which 626 (65.7%) were from major cities, 227 (23.8%) inner regional, 84 (8.8%) outer regional, 9 (0.9%) remote, and 7 (0.7%) very remote areas. Rural patients were more likely to undergo PE for primary rectal cancer (p = 002) and less likely for recurrent, non-rectal carcinoma (p = 0.027). Rural patients less frequently had health insurance (p < 0.001) but were more likely to have undergone neoadjuvant radiotherapy (p = 0.022). No difference in length-of-admission, in-hospital complication rates, QoL at 36 months or survival was observed between groups.

CONCLUSIONS

Despite geographical disparities, rural populations undergoing PE achieved equally favourable outcomes as populations from metropolitan areas. Enhancing access to specialised care may facilitate better outcomes of patients residing in regional and remote areas.

Normothermic Ex Vivo Machine Perfusion for Liver Transplantation: A Systematic Review of Progress in Humans

BACKGROUND

Liver transplantation is a lifesaving procedure for patients with end-stage liver disease (ESLD). However, many patients never receive a transplant due to insufficient donor supply. Historically, organs have been preserved using static cold storage (SCS). However, recently, ex vivo normothermic machine perfusion (NMP) has emerged as an alternative technique. This paper aims to investigate the clinical progress of NMP in humans.

METHODS

Papers evaluating the clinical outcomes of NMP for liver transplantation in humans were included. Lab-based studies, case reports, and papers utilizing animal models were excluded. Literature searches of MEDLINE and SCOPUS were conducted. The revised Cochrane risk-of-bias tool for randomised trials (RoB 2) and the risk of bias in nonrandomised studies for interventions (ROBINS-I) tools were used. Due to the heterogeneity of the included papers, a meta-analysis was unable to be completed.

RESULTS

In total, 606 records were identified, with 25 meeting the inclusion criteria; 16 papers evaluated early allograft dysfunction (EAD) with some evidence for lower rates using NMP compared to SCS; 19 papers evaluated patient or graft survival, with no evidence to suggest superior outcomes with either NMP or SCS; 10 papers evaluated utilization of marginal and donor after circulatory death (DCD) grafts, with good evidence to suggest NMP is superior to SCS.

CONCLUSIONS

There is good evidence to suggest that NMP is safe and that it likely affords clinical advantages to SCS. The weight of evidence supporting NMP is growing, and this review found the strongest evidence in support of NMP to be its capacity to increase the utilization rates of marginal and DCD allografts.