Weight loss interventions in living donor liver transplantation as a tool in expanding the donor pool: A systematic review and meta-analysis

The Impact of Donor Body Mass Index on Safety and Outcomes in Living Donor Liver Transplantation: An Analysis of the National United States Database

Background

The prevalence of obesity is rising in the general population. Donor obesity (body mass index ≥30 kg/m2) may potentially reduce the donor pool and impact outcomes in living donor liver transplantation (LDLT).

Methods

We utilized the national transplant database to investigate the impact of donor obesity on donor and recipient outcomes. This was a retrospective cohort study of all LDLTs performed in the United States between January 2010 and June 2023. Outcomes of interest were analyzed by univariable and multivariable logistic regression. Patient and graft survival was evaluated using Kaplan-Meier and Cox proportional analysis.

Results

Six hundred seventy-four donors with obesity and 3498 donors without obesity were analyzed. Donors with obesity had higher rates of readmission within 1 y of donation (15.9% versus 11.6%; P = 0.003). The risk of readmission was significantly different between 6 wk and 6 mo of donation (8.8% versus 5.9%; P = 0.036). Donor body mass index (odds ratio [OR], 1.460; 95% confidence interval [CI], 1.129-1.999; P = 0.004) and preoperative alkaline phosphatase levels (OR, 1.005; 95% CI, 1.000-1.011; P = 0.038) were independent predictors of donor readmission. High LDLT center volume was associated with reduced odds of donor readmission (OR, 0.509; 95% CI, 0.373-0.694; P < 0.001). Graft and recipient survival was comparable.

Conclusions

Selection of living donors with obesity may be a potential avenue to increase the available donor pool without compromising recipient outcomes; however, they are at an increased risk for readmission between 6 wk and 6 mo of donation. The reason for readmission requires further study.

Indications and results of right-lobe living donor liver transplantation

The shortage of deceased liver donor organs over the years has always posed the need to expand the donor pool. A viable alternative to deceased donors is that of the living donor. Indeed, the living donor in liver transplantation, initially in pediatric transplantation, but for several years now also in adult transplantation, is a more than viable alternative to deceased liver donation. In fact, right liver lobe donation has proven to be a surgical procedure with low impact on the donor's life in terms of morbidity and mortality, with excellent results in recipients of such organs. In recent years, an increasing number of studies have been published that show excellent results in right-lobe living donor liver transplantation, encouraging this practice not only in countries that have historically had a shortage of deceased donor organs, such as Asian countries, but making it a practice of increasing use in Western countries as well. In addition, thanks to improvements in surgical technique and the experience of high-volume centers, this surgery has also begun to be performed using minimally invasive surgical techniques, allowing us to envision ever better outcomes for both donor and recipient in the coming years.

Current Understanding of Marginal Grafts in Liver Transplantation

End-stage liver disease (ESLD), stemming from a spectrum of chronic liver pathologies including chronic liver failure, acute cirrhosis decompensation and hepatocellular carcinoma, imposes a significant global healthcare burden. Liver transplantation (LT) remains the only treatment for ESLD. However, the escalating mortality on transplant waitlists has prompted the utilization of marginal liver grafts in LT procedures. These grafts primarily encompass elderly livers, steatotic livers, livers from donation after circulatory death, split livers and those infected with the hepatitis virus. While the expansion of the donor pool offers promise, it also introduces concomitant risks. These encompass graft failure, biliary and cardiovascular complications, the recurrence of liver disease and reduced patient and graft survival. Consequently, various established strategies, ranging from improved donor-recipient matching to surgical interventions, have emerged to mitigate these risks. This article undertakes a comprehensive assessment of the current landscape, evaluating the viability of diverse marginal liver grafts. Additionally, it synthesizes approaches aimed at enhancing the quality of such marginal liver grafts. The overarching objective is to augment the donor pool and ameliorate the risk factors associated with the shortage of liver grafts.

Mitigating Health Disparities in Transplantation Requires Equity, Not Equality

Despite decades of research and evidence-based mitigation strategies, disparities in access to transplantation persist for all organ types and in all stages of the transplant process. Although some strategies have shown promise for alleviating disparities, others have fallen short of the equity goal by providing the same tools and resources to all rather than tailoring the tools and resources to one's circumstances. Innovative solutions that engage all stakeholders are needed to achieve equity regardless of race, sex, age, socioeconomic status, or geography. Mitigation of disparities is paramount to ensure fair and equitable access for those with end-stage disease and to preserve the trust of the public, upon whom we rely for their willingness to donate organs. In this overview, we present a summary of recent literature demonstrating persistent disparities by stage in the transplant process, along with policies and interventions that have been implemented to combat these disparities and hypotheses for why some strategies have been more effective than others. We conclude with future directions that have been proposed by experts in the field and how these suggested strategies may help us finally arrive at equity in transplantation.

Preventing Small-for-size Syndrome in Living Donor Liver Transplantation: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) is a well-recognized complication following liver transplantation (LT), with up to 20% developing this following living donor LT (LDLT). Preventing SFSS involves consideration of factors before the surgical procedure, including donor and recipient selection, and factors during the surgical procedure, including adequate outflow reconstruction, graft portal inflow modulation, and management of portosystemic shunts. International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplant Society of India Consensus Conference was convened in January 2023 to develop recommendations for the prediction and management of SFSS in LDLT. The format of the conference was based on the Grading of Recommendations, Assessment, Development, and Evaluation system. International experts in this field were allocated to 4 working groups (diagnosis, prevention, anesthesia, and critical care considerations, and management of established SFSS). The working groups prepared evidence-based recommendations to answer-specific questions considering the currently available literature. The working group members, independent panel, and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and evidence-based recommendations provided by working group 2 that can be implemented to prevent SFSS in LDLT patients.

Practice patterns and considerations in liver transplantation from living donors with high BMI: A review

Living Donor Liver Transplantation (LDLT) is a valuable solution to the shortage of donor organs for patients with end-stage liver disease. However, the eligibility of obese donors for LDLT remains a subject of debate. This literature review explores global practices and perceptions of LDLT, identifies donor eligibility criteria, and discusses special considerations and ethical caveats. The review highlights the need for standardized guidelines for donor selection, considering the global distribution of Body mass index and variations in population-specific criteria. It also emphasizes the importance of non-invasive testing and pre-operative optimization of liver steatosis for select obese donors. Furthermore, the review examines the outcomes and complications associated with obese donors in LDLT. The findings of this review contribute to the ongoing discussion on the inclusion of obese donors in LDLT and provide insights for future research and guideline development.

Subcutaneous Fat Obesity in a High Body Mass Index Donor Is Not a Contraindication to Living Donor Hepatectomy

Background

Living donor liver transplantation (LDLT) has revolutionized the field of transplantation without compromising donor safety. Donor safety is of paramount concern to the transplant team. BMI >35 kg/m2 is mostly considered a contraindication to liver donation. Here, we present a successful right donor hepatectomy from a donor with a BMI of 36.5 kg/m2. Case Summary. A 39-year-old wife donated her right lobe of liver to her 43-year-old husband with nonalcoholic steatohepatitis-related chronic liver disease (CLD). His indications were refractory ascites, hepatic encephalopathy, acute kidney injury, recurrent elbow and urine infections leading to cachexia. She was initially rejected due to a high BMI but failed to lose weight over the next 2 months, and the need for a transplant in her husband was imminent. With no other potential living donors, we decided to proceed with donor evaluation as she had no other comorbidity. We were surprised to find normal liver function tests and a good liver attenuation index (LAI) of +16 on a computed tomography (CT) scan. Magnetic resonance (MR) imaging revealed a fat fraction of 3%. Volumetry confirmed a remnant of 37.9% and a potential graft-to-recipient weight ratio of 1.23. V/S ratio on CT scan (visceral fat area/subcutaneous fat area at L4-level) was <0.4 confirming subcutaneous fat obesity. Both surgeries were uneventful and both donor and recipient recovered well except recipient re-exploration on postoperative day (POD)-1 due to surgical bleeding. The donor was discharged on POD-6 and recipient was discharged on POD-15. At 3 weeks of follow-up, the donor's wound is clean and well-healed, and she is already back to doing her daily life activities without any pain with normal laboratory parameters.

Conclusion

Subcutaneous fat obesity should not be considered as a contraindication to liver donation even with a BMI >35 kg/m2. A small percentage of healthy individuals will not have visceral fat obesity and may not have steatotic livers. The CT scan and MR fat fraction estimation can confirm the findings. Biopsy may be avoided if MR fat estimation is <10% in obese donors. Intraoperative visualization in these donors remains the gold standard to decide the need for biopsy. Living donor hepatectomy may be safely performed in a select group of high BMI patients (>35 kg/m2) with pure subcutaneous fat obesity in the absence of other suitable living donors.

Paired Exchange Living Donor Liver Transplantation: A Nine-year Experience From North India

BACKGROUND

Paired exchange liver transplantation is an evolving strategy to overcome ABO blood group incompatibility and other barriers such as inadequate graft-to-recipient weight ratio and low remnant liver volume in donors. However, for the transplant team to carry 4 major operations simultaneously is a Herculean effort. We analyzed our experience with liver paired exchange (LPE) program over the past 9 y.

METHODS

This prospective study included 34 of 2340 (1.45%) living donor liver transplantations performed between May 2012 and April 2021. The reason for LPE was ABO incompatibility in all (n = 34) patients included in the study. After donor reassignment through 2-by-2 paired exchange with directed donors, the ABO matching status changed from A to A (n = 17) and B to B (n = 17), which made all matches ABO-identical. Recipients (R) and donors (D) of each swap pair were prospectively divided into R1/D1 and R2/D2 groups for comparative and survival analyses.

RESULTS

The recipients (n = 34) had a median age of 45.5 y (11-59 y), and 31 were men. LPEs were performed in 4 operating rooms running simultaneously by 2 independent surgical teams. Donor survival was 100%. Baseline clinical and perioperative parameters, postoperative complications, median intensive care unit/hospital stay, and early deaths were comparable (P > 0.1) between the R1 and R2 groups. The median follow-up period was 27 mo (1-108 mo). The 30-d and 1-y survivals were 88.2% (n = 30) and 85.3% (n = 29), respectively.

CONCLUSIONS

Our experience suggests that with careful attention to ethical and logistical issues, the LPE program can expand the living donor liver pool and facilitate a greater number of living donor liver transplantations.

The impact of liver steatosis on the postoperative evolution after right lobe living-donor hepatectomy

Background

Living donor liver transplantation has become a feasible treatment modality for end-stage liver disease. The obesity epidemic worldwide has made it increasingly common to encounter liver steatosis in living donor candidates. The aim of study was to analyze the impact of moderate hepatic steatosis on the postoperative evolutions after right lobe living-donor hepatectomy.

Methods

Living donors who underwent donor hepatectomy during the period 2000 to 2020 in two medical centers were included in this study. We distinguished 3 groups based on the degree of steatosis: Group O - 0%, Group I - 1-10% and Group II >10%.

Results

A total number of 157 living donors underwent surgery, of whom 112 (71.34%) were right lobe liver donors. There were 62 without steatosis, 31 - with steatosis 1-10% and 19 with steatosis >10%. No difference has been found in proportion of men, median of age, body mass index and left lobe/total liver volume ration in compared groups. Total liver volume was significantly higher in the Group I than in the Group O (p=0.028). The moderate hepatic steatosis (HS) group presented significant higher volume of intraoperative hemorrhage than no-HS group (p=0.041). No differences were observed in the postoperative liver function between the groups. The minimal HS group comprised a significantly higher proportion of postoperative complications than no-HS group (67.7% vs 40.3%, p=0.043). The longer postoperative length of hospital stay in ICU was observed in Group I than in Group O (p=0.024).

Conclusion

Moderate HS does not importantly impair living liver donors' safety.