Impact of donor age on liver transplant outcomes in patients with hepatocellular carcinoma: analysis of the SRTR database

Outcomes of Patients with Hepatocellular Carcinoma Undergoing Liver Transplantation Utilizing Extended Criteria Donor Grafts

BACKGROUND

The deceased donor shortage in the United States has led to increased utilization extended criteria donor (ECD) liver grafts. Centers often utilize ECD grafts in patients with low Model for End-Stage Liver Disease (MELD) scores, like patients with hepatocellular carcinoma (HCC). However, few studies have directly examined the outcomes of using ECD grafts in patients with HCC.

METHODS

Adults receiving liver transplantation (LT) for HCC between 2010 and 2020 were identified in the Organ Procurement and Transplantation Network database. Recipients were categorized according to donor type: standard criteria donor (SCD), extended criteria donor, donation after brain death (ECD-DBD), and donation after circulatory death (DCD). Multivariable Cox regression analysis identified variables associated with overall or graft survival at 3 years post-LT.

RESULTS

Most patients received ECD-DBD grafts (51.4%); only 8.3% received DCD grafts. The time on the waitlist was similar for ECD and SCD recipients (P = .79). SCD recipients had higher 5-year overall survival post-LT than ECD-DBD or DCD recipients (79.1%, 77.1%, and 76.8%, respectively, P < .001). Similarly, 5-year graft survival was also highest in SCD recipients (SCD = 77.8%, ECD-DBD = 75.7%, and DCD = 72.2%, P < .001). In multivariable analysis, DCD grafts increased mortality risk (hazard ratio [HR] = 1.33, 95% confidence interval [CI] = 1.12-1.57, P = .001), but ECD-DBD grafts did not (HR = 1.10, 95% CI = 1.00-1.22, P = .052).

CONCLUSIONS

DCD and ECD-DBD recipients had significantly lower overall and graft survival. However, the survival benefit of LT for patients with HCC greatly outweighs the small differences in patient and graft survival from using ECD grafts. Further research should investigate whether treatment of ECD grafts with machine perfusion may ameliorate this discrepancy.

Machine Perfusion as a Strategy to Decrease Ischemia-Reperfusion Injury and Lower Cancer Recurrence Following Liver Transplantation

Liver transplantation (LT) is a key treatment for primary and secondary liver cancers, reducing tumor burden with concurrent improvement of liver function. While significant improvement in survival is noted with LT, cancer recurrence rates remain high. Mitochondrial dysfunction caused by ischemia-reperfusion injury (IRI) is known to drive tumor recurrence by creating a favorable microenvironment rich in pro-inflammatory and angiogenic factors. Therefore, strategies that decrease reperfusion injury and mitochondrial dysfunction may also decrease cancer recurrence following LT. Machine perfusion techniques are increasingly used in routine clinical practice of LT with improved post-transplant outcomes and increased use of marginal grafts. Normothermic (NMP) and hypothermic oxygenated machine perfusion (HOPE) provide oxygen to ischemic tissues, and impact IRI and potential cancer recurrence through different mechanisms. This article discussed the link between IRI-associated inflammation and tumor recurrence after LT. The current literature was screened for the role of machine perfusion as a strategy to mitigate the risk of cancer recurrence. Upfront NMP ("ischemia free organ transplantation") and end-ischemic HOPE were shown to reduce hepatocellular carcinoma recurrence in retrospective studies. Three prospective randomized controlled trials are ongoing in Europe to provide robust evidence on the impact of HOPE on cancer recurrence in LT.

The role of ischaemia-reperfusion injury and liver regeneration in hepatic tumour recurrence

The risk of cancer recurrence after liver surgery mainly depends on tumour biology, but preclinical and clinical evidence suggests that the degree of perioperative liver injury plays a role in creating a favourable microenvironment for tumour cell engraftment or proliferation of dormant micro-metastases. Understanding the contribution of perioperative liver injury to tumour recurrence is imperative, as these pathways are potentially actionable. In this review, we examine the key mechanisms of perioperative liver injury, which comprise mechanical handling and surgical stress, ischaemia-reperfusion injury, and parenchymal loss leading to liver regeneration. We explore how these processes can trigger downstream cascades leading to the activation of the immune system and the pro-inflammatory response, cellular proliferation, angiogenesis, anti-apoptotic signals, and release of circulating tumour cells. Finally, we discuss the novel therapies under investigation to decrease ischaemia-reperfusion injury and increase regeneration after liver surgery, including pharmaceutical agents, inflow modulation, and machine perfusion.

Evaluating the outcomes of donor-recipient age differences in young adults undergoing liver transplantation

The current liver allocation system may be disadvantaging younger adult recipients as it does not incorporate the donor-recipient age difference. Given the longer life expectancy of younger recipients, the influences of older donor grafts on their long-term prognosis should be elucidated. This study sought to reveal the long-term prognostic influence of the donor-recipient age difference in young adult recipients. Adult patients who received initial liver transplants from deceased donors between 2002 and 2021 were identified from the UNOS database. Young recipients (patients 45 years old or below) were categorized into 4 groups: donor age younger than the recipient, 0-9 years older, 10-19 years older, or 20 years older or above. Older recipients were defined as patients 65 years old or above. To examine the influence of the age difference in long-term survivors, conditional graft survival analysis was conducted on both younger and older recipients. Among 91,952 transplant recipients, 15,170 patients were 45 years old or below (16.5%); these were categorized into 6,114 (40.3%), 3,315 (21.9%), 2,970 (19.6%), and 2,771 (18.3%) for groups 1-4, respectively. Group 1 demonstrated the highest probability of survival, followed by groups 2, 3, and 4 for the actual graft survival and conditional graft survival analyses. In younger recipients who survived at least 5 years post-transplant, inferior long-term survival was observed when there was an age difference of 10 years or above (86.9% vs. 80.6%, log-rank p <0.01), whereas there was no difference in older recipients (72.6% vs. 74.2%, log-rank p =0.89). In younger patients who are not in emergent need of a transplant, preferential allocation of younger aged donor offers would optimize organ utility by increasing postoperative graft survival time.

The prognostic relationship between donor age and infectious risk in liver transplant patients with nonalcoholic steatohepatitis: Analysis of UNOS database

BACKGROUND & AIMS

We investigate the effects of advancing donor age on the prognostic outcomes of patients with NASH who undergo liver transplant (LT), with a specialized attention toward infectious outcomes post-LT.

METHODS

The UNOS-STAR registry was used to select 2005 to 2019 LT recipients with NASH, who were stratified by donor age into the following categories: recipients with younger donors (less than 50 years of age-reference), quinquagenarian donors, sexagenarian donors, septuagenarian donors, and octogenarian donors. Cox regression analyses were conducted for all-cause mortality, graft failure, infectious causes of death.

RESULTS

From a total of 8888 recipients, the quinquagenarian, septuagenarian, and octogenarian donor cohorts showed greater risk of all-cause mortality (quinquagenarian: aHR 1.16 95%CI 1.03-1.30; septuagenarian: aHR 1.20 95%CI 1.00-1.44; octogenarian: aHR 2.01 95%CI 1.40-2.88). With advancing donor age, there was an increased risk of death from sepsis (quinquagenarian: aHR 1.71 95% CI 1.24-2.36; sexagenarian: aHR 1.73 95% CI 1.21-2.48; septuagenarian: aHR 1.76 95% CI 1.07-2.90; octogenarian: aHR 3.58 95% CI 1.42-9.06) and infectious causes (quinquagenarian: aHR 1.46 95% CI 1.12-1.90; sexagenarian: aHR 1.58 95% CI 1.18-2.11; septuagenarian: aHR 1.73 95% CI 1.15-2.61; octogenarian: aHR 3.70 95% CI 1.78-7.69).

CONCLUSION

NASH patients who receive grafts from elderly donors exhibit higher risk of post-LT mortality, especially due to infection.

Liver transplantation for NAFLD cirrhosis: Age and recent coronary angioplasty are major determinants of survival

BACKGROUND AND AIMS

Liver transplantation (LT) is the treatment of end-stage non-alcoholic liver disease (NAFLD), that is decompensated cirrhosis and/or complicated by hepatocellular carcinoma (HCC). Few data on long-term outcome are available. The aim of this study was to evaluate overall patient and graft survivals and associated predictive factors.

METHOD

This retrospective multicentre study included adult transplant patients for NAFLD cirrhosis between 2000 and 2019 in participating French-speaking centres.

RESULTS

A total of 361 patients (69.8% of male) were included in 20 centres. The median age at LT was 62.3 years [57.4-65.9] and the median MELD score was 13.9 [9.1-21.3]; 51.8% of patients had HCC on liver explant. Between 2004 and 2018, the number of LT for NAFLD cirrhosis increased by 720%. A quarter of the patients had cardiovascular history before LT. Median follow-up after LT was 39.1 months [15.8-72.3]. Patient survival at 1, 5 and 10 years after LT was 89.3%, 79.8% and 68.1% respectively. The main causes of death were sepsis (37.5%), malignancies (29.2%) and cardiovascular events (22.2%). In multivariate analysis, three risk factors for overall mortality after LT were recipient pre-LT BMI < 32 kg/m² at LT time (OR: 2.272; p = .012), pre-LT angioplasty during CV check-up (OR: 2.916; p = .016), a combined donor and recipient age over 135 years (OR: 2.020; 95%CI: p = .035).

CONCLUSION

Survival after LT for NAFLD cirrhosis is good at 5 years. Donor and recipient age, and cardiovascular history, are major prognostic factors to consider.

Liver transplantation in patients with liver failure: Twenty years of experience from China

Liver transplantation (LT) is the only effective method of treating end-stage liver disease, such as various types of liver failure. China has the largest number of patients with hepatitis B virus-related disease, which is also the main cause of liver failure. From the first LT performed in 1977, and especially over the past two decades, LT has experienced rapid development as a result of continuous research and innovation in China. China performs the second-highest number of LTs every year worldwide, and the quality of LT continues to improve. Starting January 1, 2015, all donor's livers have been from deceased donors and familial donors. Thus, China entered into a new era of LT. However, LT is still a challenging procedure in China. In this review, we introduced the brief history of LT in China, the epidemiology, aetiology and clinical outcomes of LT for liver failure in China and summarized the experience of LT from Chinese LT surgeons and scholars. The future perspectives of LT were also discussed, and it is expected that China's LT research could be further integrated elsewhere in the world.

Small-For-Size Syndrome and Graft Inflow Modulation Techniques in Liver Transplantation

BACKGROUND

Partial liver transplantation has recently been proposed to alleviate organ shortages. However, transplantation of a small-for-size graft is associated with an increased risk of posttransplant hepatic dysfunction, commonly referred to as small-for-size syndrome (SFSS). This review describes the etiology, pathological features, clinical manifestations, and diagnostic criteria of SFSS. Moreover, we summarize strategies to improve graft function, focusing on graft inflow modulation techniques. Finally, unmet needs and future perspectives are discussed.

SUMMARY

In fact, posttransplant SFSS can be attributed to various factors such as preoperative status of the recipients, surgical techniques, donor age, and graft quality, except for graft size. With targeted improvement measures, satisfactory clinical outcomes can be achieved in recipients at increased risk of SFSS. Given the critical role of relative portal hyperperfusion in the pathogenesis of SFSS, various pharmacological and surgical treatments have been established to reduce or partially divert excessive portal inflow, and recipients will benefit from individualized therapeutic regimens after careful evaluation of benefits against potential risks. However, there remain unmet needs for further research into different aspects of SFSS to better understand the correlation between portal hemodynamics and patient outcomes.

KEY MESSAGES

Contemporary transplant surgeons should consider various donor and recipient factors and develop case-specific prevention and treatment strategies to improve graft and recipient survival rates.