The first case of ischemia-free organ transplantation in humans: A proof of concept

Simplified ischemia-free liver transplantation by providing alternating flow of the portal vein and hepatic artery: Applicability, efficiency, and safety

Conventional ischemia-free liver transplantation (CIFLT) represents a pioneering procedure that circumvents ischemia-reperfusion injury to livers throughout the transplant procedure. However, its complexity has limited its widespread adoption. This study introduced a simplified ischemia-free liver transplantation (SIFLT) technique by providing an alternating flow of the portal vein and hepatic artery, demonstrating its efficacy and safety. In this retrospective study, 32 patients who received SIFLT and 32 who received CIFLT were included between January 2021 and January 2024. The intraoperative and postoperative outcomes were collected and elevated. Patients who underwent SIFLT had a shorter anhepatic phase (44.0±2.4 vs. 51.6±2.4 min, p =0.03), along with a comparatively reduced intraoperative blood loss compared to those who underwent CIFLT. Furthermore, the SIFLT group exhibited significantly lower peak AST levels within postoperative 7 days (413.1±62.6 vs. 707.5±110.7 U/L, p =0.02). The incidence of early allograft dysfunction, primary nonfunction, and transplant-related complications were similar across both groups. There were no significant differences in the number of Clavien-Dindo classification of surgical complications and comprehensive complication index at 3 months after transplantation. Kaplan-Meier analysis confirmed similar patient and graft survival rates. The subgroup analysis of extended criteria donor demonstrated that SIFLT can effectively reduce anhepatic phase and intraoperative blood loss and can achieve a clinical prognosis similar to CIFLT. Additionally, histological analysis revealed that both groups demonstrated well-preserved livers and bile ducts. The SIFLT simplifies the intricate surgical procedure while ensuring the protection of livers from ischemia-reperfusion injury. This technique holds promise for enabling patients to achieve clinical outcomes comparable to those of CIFLT.

Protective value of ischemia-free liver transplantation on post-transplant acute kidney injury

Background & Aims

Ischemia-free liver transplantation (IFLT) completely avoids ischemia-reperfusion injury (IRI), thus potentially reducing acute kidney injury (AKI) after liver transplantation (LT). Therefore, this study investigated whether IFLT has a protective effect against AKI after LT.

Methods

In total, 862 patients who had undergone LT between 2017 to 2022 were divided into an ischemia-free liver transplantation group (IFLT group) and conventional liver transplantation group (CLT group) based on the surgical methods used. Propensity score matching (PSM) was used for post hoc randomization in the 1:1 matching between the groups. Post-transplant kidney function, graft function, and patient survival were compared between the groups. Multivariate logistic regression analysis was used to identify the risk factors of AKI after LT.

Results

Overall, 745 out of 862 patients were finally enrolled, of whom 98 underwent IFLT. PSM created 94 pairs of patients. IFLT resulted in a significant reduction in Stage-3 AKI (3.2% vs. 16.0%, p = 0.003), severe AKI (SAKI) (13.8% vs. 25.5%, p = 0.044), and renal replacement therapy (RRT) ratio (3.2% vs. 12.8%, p = 0.015) compared with the CLT group. The early allograft dysfunction (EAD) incidence of the IFLT group significantly decreased (8.5% vs. 44.7%, p <0.001). Livers from the extended criteria donation (ECD) were received in 49 patients who underwent IFLT and 46 patients who underwent CLT. Compared with the ECD-CLT group, the Stage-3 AKI and SAKI incidence in the ECD-IFLT group were both decreased (p <0.05). Multivariate logistic regression analysis further confirmed that both using IFLT and avoiding ECD were protective factors for post-transplant Stage-3 AKI.

Conclusions

IFLT significantly reduces the incidence of post-transplant SCKI, Stage-3 AKI, and RRT. Importantly, this protective effect is also present in patients receiving ECD livers.

Impact and implications

Ischemia-free liver transplantation significantly reduces the incidence of severe acute kidney injury, Stage-3 acute kidney injury and renal replacement therapy after liver transplantation. Importantly, this protective effect is also present in patients receiving extended criteria donation livers.

Clinical trial number

ChiCTR2400081755.

A comparison of hemodynamic measurement methods during orthotopic liver transplantation: evaluating agreement and trending ability of PiCCO versus pulmonary artery catheter techniques

BACKGROUND

Significant hemodynamic changes occur during liver transplantation, emphasizing the importance of precious and continuous monitoring of cardiac output, cardiac index, and other parameters. Although the monitoring of cardiac output by pulse indicator continuous cardiac output (PiCCO) was statistically homogeneous compared to the clinical gold standard pulmonary artery catheterization (PAC) in previous studies of liver transplantation, there are fewer statistical methods for the assessment of its conclusions, and a lack of comparisons of other hemodynamic parameters (e.g., SVRI, systemic vascular resistance index). Some studies have also concluded that the agreement between PiCCO and PAC is not good enough. Overall, there are no uniform conclusions regarding the agreement between PiCCO and PAC in previous studies. This study evaluates the agreement and trending ability of relevant hemodynamic parameters obtained with PiCCO compared to the clinical gold standard PAC from multiple perspectives, employing various statistical methods.

METHODS

Fifty-two liver transplantation patients were included. Cardiac output (CO), cardiac index (CI), SVRI and stroke volume index (SVI) values were monitored at eight time points using both PiCCO and PAC. The results were analyzed by Bland-Altman analysis, Passing-bablok regression, intra-class correlation coefficient (ICC), 4-quadrant plot, polar plot, and trend interchangeability method (TIM).

RESULTS

The Bland-Altman analysis revealed high percentage errors for PiCCO: 54.06% for CO, 52.70% for CI, 62.18% for SVRI, and 51.97% for SVI, indicating poor accuracy. While Passing-Bablok plots showed favorable agreement for SVRI overall and during various phases, the agreement for other parameters was less satisfactory. The ICC results confirmed good overall agreement between the two devices across most parameters, except for SVRI during the new liver phase, which showed poor agreement. Additionally, four-quadrant and polar plot analyses indicated that all agreement rate values fell below the clinically acceptable threshold of over 90%, and all angular deviation values exceeded ± 5°, demonstrating that PiCCO is unable to meet the acceptable trends. Using the TIM, the interchangeability rates were found to be quite low: 20% for CO and CI, 16% for SVRI, and 13% for SVI.

CONCLUSIONS

Our study revealed notable disparities in absolute values of CO, CI, SVRI and SVI between PiCCO and PAC in intraoperative liver transplant settings, notably during the neohepatic phase where errors were particularly pronounced. Consequently, these findings highlight the need for careful consideration of PiCCO's advantages and disadvantages in liver transplantation scenarios, including its multiple parameters (such as the encompassing extravascular lung water index), against its limited correlation with PAC.

Application of extended criteria donor grafts in liver transplantation for acute-on-chronic liver failure: A retrospective cohort study

BACKGROUND

There is no consensus on the usage of extended criteria donor (ECD) grafts in liver transplantation (LT) for acute-on-chronic liver failure (ACLF) patients.

AIM

To summarize the experience of using ECD livers in ACLF-LT.

METHODS

A retrospective cohort study was conducted, enrolling patients who underwent LT at the First Affiliated Hospital of Sun Yat-Sen University from January 2015 to November 2021. The patients were divided into ECD and non-ECD groups for analysis.

RESULTS

A total of 145 recipients were enrolled in this study, of which ECD and non-ECD recipients accounted for 53.8% and 46.2%, respectively. Donation after cardiac death (DCD) recipients accounted for the minority compared with donation after brain death (DBD) recipients (16.6% vs 83.4%). Neither overall survival nor graft survival significantly differed between ECD and non-ECD and DCD and DBD recipients. ECD grafts were associated with a significantly higher incidence of early allograft dysfunction (EAD) than non-ECD grafts (67.9% vs 41.8%, P = 0.002). Postoperative outcomes between DCD and DBD recipients were comparable (P > 0.05). ECD graft (P = 0.009), anhepatic phase (P = 0.034) and recipient gamma glutamyltransferase (P = 0.016) were independent risk factors for EAD. Recipient preoperative number of extrahepatic organ failures > 2 (P = 0.015) and intraoperative blood loss (P = 0.000) were independent predictors of poor post-LT survival.

CONCLUSION

Although related to a higher risk of EAD, ECD grafts can be safely used in ACLF-LT. The main factors affecting post-LT survival in ACLF patients are their own severe preoperative disease and intraoperative blood loss.

Changing liver utilization and discard rates in clinical transplantation in the ex-vivo machine preservation era

Liver transplantation is a well-established treatment for many with end-stage liver disease. Unfortunately, the increasing organ demand has surpassed the donor supply, and approximately 30% of patients die while waiting for a suitable liver. Clinicians are often forced to consider livers of inferior quality to increase organ donation rates, but ultimately, many of those organs end up being discarded. Extensive testing in experimental animals and humans has shown that ex-vivo machine preservation allows for a more objective characterization of the graft outside the body, with particular benefit for suboptimal organs. This review focuses on the history of the implementation of ex-vivo liver machine preservation and how its enactment may modify our current concept of organ acceptability. We provide a brief overview of the major drivers of organ discard (age, ischemia time, steatosis, etc.) and how this technology may ultimately revert such a trend. We also discuss future directions for this technology, including the identification of new markers of injury and repair and the opportunity for other ex-vivo regenerative therapies. Finally, we discuss the value of this technology, considering current and future donor characteristics in the North American population that may result in a significant organ discard.

Machine perfusion of the liver: applications in transplantation and beyond

The shortage of donor livers considered suitable for transplantation has driven the development of novel methods for organ preservation and reconditioning. Machine perfusion techniques can improve the quality of marginal livers, extend the time for which they can be preserved and enable an objective assessment of their quality and viability. These benefits can help avoid the needless wastage of organs based on hypothetical concerns regarding quality. As machine perfusion techniques are gaining traction in clinical practice, attention has now shifted to their potential applications beyond transplantation. As well as providing an update on the current status of machine perfusion in clinical practice, this Perspective discusses how this technology is being used as a tool for therapeutic interventions including defatting of steatotic livers, immunomodulation and gene therapies.

Ex Situ Machine Perfusion of Human Donor Livers via the Surgically Reopened Umbilical Vein: A Proof of Concept

BACKGROUND

Machine perfusion of donor livers is typically performed via the portal vein main stem. Instead, cannulation of a reopened umbilical vein could allow machine perfusion during organ procurement and subsequent implantation in the recipient without interruption of the portal venous circulation. We aimed to assess the feasibility of portal venous machine perfusion via the umbilical vein.

METHODS

During back table inspection of 5 human livers declined for transplantation, the umbilical vein was surgically reopened, dilated, and cannulated. Hypothermic and normothermic oxygenated machine perfusion (NMP) were performed using the umbilical vein for portal inflow. Three livers were perfused with hypothermic machine perfusion, 1 full liver graft underwent NMP for 4 hours, and 1 left lateral split procedure was performed under continuous NMP with portal perfusion via the umbilical vein.

RESULTS

In all livers, access to the portal venous system via the umbilical vein was successfully achieved with good portal flows and macroscopically homogeneous perfusion. The full liver graft that underwent NMP via the umbilical vein for 4 hours showed good lactate clearance, normalized pH, and achieved good bile production with pH >7.55. During the split procedure under continuous NMP via the umbilical vein, the left lateral segment and extended right lobe remained equally perfused, as demonstrated by Doppler ultrasound.

CONCLUSIONS

Machine perfusion with portal perfusion via the umbilical vein is feasible. Portal venous flows were similar to those obtained after cannulation of the portal vein main stem. This technique enables continuous oxygenated perfusion of liver grafts during procurement, splitting, and implantation.