The Concept of Functional Graft Size: An Eternal Theme of Maximizing Donor Safety and Recipient Survival in Living Donor Liver Transplantation

Recipient 3-Hepatic Vein Technique with Graft Venoplasty to Maximize Venous Outflow in Left Lobe Living Donor Liver Transplantation

Background

Augmentation of hepatic venous outflow is crucial in living donor liver transplantation (LDLT) to maximize functional graft size and prevent venous complications. We present details of our outflow augmentation technique for left lobe grafts (LLG) in adult LDLTs, which uses all recipient 3 hepatic veins and venoplasty of graft left and middle hepatic veins. This study examines the effectiveness of our technique in preventing outflow complications and the correlation between anatomical variations of the graft hepatic veins and surgical outcomes.

Methods

We retrospectively reviewed 88 patients who underwent LLG-LDLT between 2012 and 2023. The patients were classified into 3 groups based on the graft hepatic vein anatomy and usage of venoplasty: group 1 (n = 10, common trunk without venoplasty), group 2 (n = 62, common trunk with venoplasty), and group 3 (n = 16, no common trunk with venoplasty).

Results

No patient developed clinically significant venous outflow complications or graft loss related to venous outflow. There were no significant differences in complication rates or ascites production among the groups. Five-year graft survival was comparable among the groups (P = 0.43). Multiple regression analysis revealed that the model for end-stage liver disease score was the only independent risk factor for increased ascites after transplant (standardized beta, 0.546; t value,4.20; P < 0.001; 95% confidence interval, 0.287-0.804), but anatomical variations of the graft hepatic veins did not influence ascites output.

Conclusions

The recipient 3 hepatic vein outflow augmentation technique with graft venoplasty can be applied to various graft hepatic venous anatomy and effectively prevents outflow-related graft loss in LLG-LDLT.

The aim of donor safety: surgical approaches and current results

Living liver donation (LLD) has been suggested as a potential solution to reduce the waitlist mortality for liver transplantation (LT) recipients by facilitating living donor liver transplantation (LDLT). Ensuring both donor and recipient safety is a critical aspect of LDLT. An accurate understanding of the complexity and extend of safety outcomes of the donor is imperative to maintain the high-quality standard this medical program requires. This review seeks to outline safety outcome parameters of interest for donors. Early postoperative mortality is very low with no significant differences comparing left lobe to right lobe LLD. Complications most commonly are biliary (leakage or strictures), bleeding, respiratory or pulmonary, gastrointestinal or infectious. Return to full-time work and quality of life are essential parameters in the mid and long term. As evidence continues to accumulate, outcomes may evolve with the expansion of minimal invasive surgery practice and currently laparoscopic approach is recommended in large experienced centers. By offering safer operations that require fewer incisions or liver resections, living liver donations can be further encouraged, and the perception of the procedure can be improved. Rational consideration of the safety of the donor and in-depth discussion and evaluation with the patient is of utmost importance.

Outcomes of living donor liver transplant recipients receiving grafts with the graft-to-recipient weight ratio less than 0.6%: A matched pair analysis

We sometimes experience living donor liver transplantation (LDLT) involving very small grafts with graft-to-recipient weight ratio (GRWR) < 0.6% when the actual graft size is smaller than predicted. The outcomes in this situation have not been fully investigated. The present study aimed to determine the graft outcomes of LDLT with GRWR < 0.6%. We retrospectively reviewed 280 cases of adult LDLT performed at our institution between January 2000 and March 2021. In our institution, the lower limit for graft volume/standard liver volume ratio was 30%. The patients were divided into 2 groups according to the cutoff value of 0.6% for actual GRWR. Graft survival and surgical outcomes, including small-for-size syndrome (SFSS), were compared between the groups using propensity score matching analysis. Risk factors associated with SFSS in recipients with GRWR < 0.6% were also evaluated. Fifty-nine patients received grafts with GRWR < 0.6%. After propensity score matching, similar graft survival rates were observed for GRWR < 0.6% (n = 53) and GRWR ≥ 0.6% (n = 53) ( p = 0.98). However, patients with GRWR < 0.6% had a significantly worse 3-month graft survival rate (86.8% vs. 98.1%, p = 0.03) and higher incidence of SFSS ( p < 0.001) than patients with GRWR ≥0.6%. On multivariate analysis, Model for End-Stage Liver Disease score and donor age were associated with SFSS in patients with GRWR < 0.6%. The same factors were also associated with graft survival. In conclusion, although similar overall graft survival rates were observed for LDLT with GRWR < 0.6% and GRWR ≥ 0.6%, GRWR < 0.6% was associated with an increased risk of SFSS. Appropriate donor and recipient selection is important for successful LDLT with very small grafts.

Three-dimensional Liver Model Application for Liver Transplantation

BACKGROUND

Children are removed from the liver transplant waitlist because of death or progressive illness. Size mismatch accounts for 30% of organ refusal. This study aimed to demonstrate that 3-dimensional (3D) technology is a feasible and accurate adjunct to organ allocation and living donor selection process.

METHODS

This prospective multicenter study included pediatric liver transplant candidates and living donors from January 2020 to February 2023. Patient-specific, 3D-printed liver models were used for anatomic planning, real-time evaluation during organ procurement, and surgical navigation. The primary outcome was to determine model accuracy. The secondary outcome was to determine the impact of outcomes in living donor hepatectomy. Study groups were analyzed using propensity score matching with a retrospective cohort.

RESULTS

Twenty-eight recipients were included. The median percentage error was -0.6% for 3D models and had the highest correlation to the actual liver explant (Pearson's R = 0.96, P < 0.001) compared with other volume calculation methods. Patient and graft survival were comparable. From 41 living donors, the median percentage error of the allograft was 12.4%. The donor-matched study group had lower central line utilization (21.4% versus 75%, P = 0.045), shorter length of stay (4 versus 7 d, P = 0.003), and lower mean comprehensive complication index (3 versus 21, P = 0.014).

CONCLUSIONS

Three-dimensional volume is highly correlated with actual liver explant volume and may vary across different allografts for living donation. The addition of 3D-printed liver models during the transplant evaluation and organ procurement process is a feasible and safe adjunct to the perioperative decision-making process.

Evaluation of living donors for hereditary liver disease (siblings, heterozygotes)

Living donor liver transplantation (LDLT) is recognised as an alternative treatment modality to reduce waiting list mortality and expand the donor pool. Over recent decades, there have been an increasing number of reports on the use of LT and specifically LDLT for familial hereditary liver diseases. There are marginal indications and contraindications that should be considered for a living donor in paediatric parental LDLT. No mortality or morbidity related to recurrence of metabolic diseases has been observed with heterozygous donors, except for certain relevant cases, such as ornithine transcarbamylase deficiency, protein C deficiency, hypercholesterolemia, protoporphyria, and Alagille syndrome, while donor human leukocyte antigen homozygosity also poses a risk. It is not always essential to perform preoperative genetic assays for possible heterozygous carriers; however, genetic and enzymatic assays must hereafter be included in the parental donor selection criteria in the aforementioned circumstances.

Living Donor Liver Transplantation With Augmented Venous Outflow and Splenectomy: A Promised Land for Small Left Lobe Grafts

OBJECTIVE

Living donor liver transplantation (LDLT) using small grafts, especially left lobe grafts (H1234-MHV) (LLG), continues to be a challenge due to small-for-size syndrome (SFSS). We herein demonstrate that with surgical modifications, outcomes with small grafts can be improved.

METHODS

Between 2012 and 2020, we performed 130 adult LDLT using 61 (47%) LLG (H1234-MHV) in a single Enterprise. The median graft-to-recipient weight ratio was 0.84%, with graft-to-recipient weight ratio <0.7% accounting for 22%. Splenectomy was performed in 72 (56%) patients for inflow modulation before (n=50) or after (n=22) graft reperfusion. In LLG-LDLT, venous outflow was achieved using all three recipient hepatic veins. In right lobe graft (H5678) (RLG)-LDLT, the augmented graft right hepatic vein was anastomosed to the recipient's cava with a large cavotomy. Outcome measures include SFSS, early allograft dysfunction (EAD), and survival.

RESULTS

Graft survival rates at 1, 3, and 5 years were 94%, 90%, and 83%, respectively, with no differences between LLG (H1234-MHV) and RLG (H5678). Splenectomy significantly reduced portal flow without increasing the complication rate. Despite the aggressive use of small grafts, SFSS and EAD developed in only 1 (0.8%) and 18 (13.8%) patients, respectively. Multivariable logistic regression revealed model for end-stage liver disease score and LLG (H1234-MHV) as independent risk factors for EAD and splenectomy as a protective factor (odds ratio: 0.09; P =0.03). For LLG (H1234-MHV)-LDLT, patients who underwent prereperfusion splenectomy tended to have better 1-year graft survival than those receiving postreperfusion splenectomy.

CONCLUSIONS

LLG (H1234-MHV) are feasible in adult LDLT with excellent outcomes comparable to RLG (H5678). Venous outflow augmentation and splenectomy help lower the threshold of using small-for-size grafts without compromising graft survival.