Center use of technical variant grafts varies widely and impacts pediatric liver transplant waitlist and recipient outcomes in the United States

Living Donor Whole and Partial Liver Grafts, Deceased Donor Whole Liver and SPLIT: Outcome Comparison

BACKGROUND

Currently, graft options for pediatric liver transplantation (PLT) include whole (WL) and partial (P) grafts, in the form of either deceased donor transplantation (DD) or living donor liver transplantation (LD). WL transplants from LD are commonly referred to as domino LT. The objective of this manuscript is to compare the outcomes of PLT performed with each of the available graft options.

METHODS

Retrospective cohort study from Jan. 2010 to Dec. 2022. The variables included data on the recipients' preoperative clinical status, intraoperative technical aspects, post-operative complications, and survival studies. There were 4 groups: SPLIT (17), DD-WL (55), LD-WL (824), and LD-P (22).

RESULTS

The median age and BW of the recipients was smaller in SPLIT, LD-P, and LD-WL compared to DDT-WL groups. HVOO (HR 15.87, 95% CI 1.89-133.06, P = 0.01), retransplantation (HR 7.94, 95% CI 2.63-24.02, P < 0.01), and malignancies (HR 3.08, 95% CI 1.29-7.37, P = 0.01) were independently associated with decreased patient survival. HAT (HR 27.54, 95% CI 10.44-72.68, P < 0.01) and malignancies (HR 2.42, 95% CI 1.10-5.34, P = 0.03) increased the risk of graft loss. The overall survival in this series was 91.4% (mean follow-up of 74.3 months). Patient and graft survival were not different among groups.

CONCLUSION

HAT and malignancies were associated with reduced graft survival. Whole liver from living donors with MSUD presented 100% patient survival at 120 months. Even without statistical differences in survival among the studied groups, LD-P and LD-WL recipients presented a trend towards better outcomes.

LEVEL OF EVIDENCE

LEVEL III.

Normothermic Liver Machine Perfusion and Successful Transplantation of Split Liver Grafts: From Proof of Concept to Clinical Implementation

BACKGROUND

Normothermic liver machine perfusion (NLMP) is advancing the field of liver transplantation (LT). Beyond improved preservation and organ assessment, NLMP helps to increase organ utilization. We herein address the feasibility and merit of NLMP in split liver transplantation (SLT) to postpone the transplantation of the second split graft to the following day.

METHODS

We analyzed the perfusion characteristics and outcomes of all consecutive adult recipients who underwent SLT following NLMP from February 1, 2018, to June 30, 2023. The primary endpoint was 90-d graft and patient survival. Secondary endpoints were posttransplant complications and 90-d morbidity.

RESULTS

Three right and 3 extended right SLT following NLMP have been performed. NLMP was uneventful in all cases. Perfusion characteristics differed according to graft volume. Mean perfusion time was 17:00 h (±05:13) and bile production ranged between 8 and 21 mL/h. All split grafts fulfilled predefined center viability criteria during NLMP and were transplanted on the following day. The 90-d graft and patient survival rate was 100%. Three patients (50%) required an early relaparotomy, and 2 patients (33.3%) developed biliary complications. The 90-d morbidity as recorded by the comprehensive complication index was 62.7 (±24.7).

CONCLUSIONS

NLMP of split liver grafts is technically feasible and safe. Through prolongation of preservation time, NLMP allows to safely postpone transplantation of the second split liver graft to the next day.

Optimizing pediatric liver transplantation: Evaluating the impact of donor age and graft type on patient survival outcome

BACKGROUND

We examined the combined effects of donor age and graft type on pediatric liver transplantation outcomes with an aim to offer insights into the strategic utilization of these donor and graft options.

METHODS

A retrospective analysis was conducted using a national database on 0-2-year-old (N = 2714) and 3-17-year-old (N = 2263) pediatric recipients. These recipients were categorized based on donor age (≥40 vs <40 years) and graft type. Survival outcomes were analyzed using the Kaplan-Meier and Cox proportional hazards models, followed by an intention-to-treat (ITT) analysis to examine overall patient survival.

RESULTS

Living and younger donors generally resulted in better outcomes compared to deceased and older donors, respectively. This difference was more significant among younger recipients (0-2 years compared to 3-17 years). Despite this finding, ITT survival analysis showed that donor age and graft type did not impact survival with the exception of 0-2-year-old recipients who had an improved survival with a younger living donor graft.

CONCLUSIONS

Timely transplantation has the largest impact on survival in pediatric recipients. Improving waitlist mortality requires uniform surgical expertise at many transplant centers to provide technical variant graft (TVG) options and shed the conservative mindset of seeking only the "best" graft for pediatric recipients.

Efficiency of machine perfusion in pediatric liver transplantation

Liver transplantation is the only life-saving procedure for children with end-stage liver disease. The field is however heterogenic with various graft types, recipient age, weight, and underlying diseases. Despite recently improved overall outcomes and the expanded use of living donors, waiting list mortality remains unacceptable, particularly in small children and infants. Based on the known negative effects of elevated donor age, higher body mass index, and prolonged cold ischemia time, the number of available donors for pediatric recipients is limited. Machine perfusion has regained significant interest in the adult liver transplant population during the last decade. Ten randomized controlled trials are published with an overall advantage of machine perfusion techniques over cold storage regarding postoperative outcomes, including graft survival. The concept of hypothermic oxygenated perfusion (HOPE) was the first and only perfusion technique used for pediatric liver transplantation today. In 2018 the first pediatric candidate received a full-size graft donated after circulatory death with cold storage and HOPE, followed by a few split liver transplants after HOPE with an overall limited case number until today. One series of split procedures during HOPE was recently presented by colleagues from France with excellent results, reduced complications, and better graft survival. Such early experience paves the way for more systematic use of machine perfusion techniques for different graft types for pediatric recipients. Clinical reports of pediatric liver transplants with other perfusion techniques are awaited. Strong collaborative efforts are needed to explore the effect of perfusion techniques in this vulnerable population impacting not only the immediate posttransplant outcome but the development and success of an entire life.

Technical Variant Liver Transplant Utilization for Pediatric Recipients: Equal Graft Survival to Whole Liver Transplants and Promotion of Timely Transplantation Only When Performed at High-volume Centers

BACKGROUND

Technical variant liver transplantation (TVLT) is a strategy to mitigate persistent pediatric waitlist mortality in the United States, although its implementation remains stagnant. This study investigated the relationship between TVLT utilization, transplant center volume, and graft survival.

METHODS

Pediatric liver transplant recipients from 2010 to 2020 (n = 5208) were analyzed using the Scientific Registry of Transplant Recipients database. Transplant centers were categorized according to the average number of pediatric liver transplants performed per year (high-volume, ≥5; low-volume, <5). Graft survival rates were compared using Kaplan-Meier curves and log-rank tests. Cox proportional hazards models were used to identify predictors of graft failure.

RESULTS

High-volume centers demonstrated equivalent whole liver transplant and TVLT graft survival ( P = 0.057) and significantly improved TVLT graft survival compared with low-volume centers ( P < 0.001). Transplantation at a low-volume center was significantly associated with graft failure (adjusted hazard ratio, 1.6; 95% confidence interval, 1.14-2.24; P = 0.007 in patients <12 y old and 1.8; 95% confidence interval, 1.13-2.87; P = 0.013 in patients ≥12 y old). A subset of high-volume centers with a significantly higher rate of TVLT use demonstrated a 23% reduction in waitlist mortality.

CONCLUSIONS

Prompt transplantation with increased TVLT utilization at high-volume centers may reduce pediatric waitlist mortality without compromising graft survival.

Revisiting the forgotten "full-right full-left" liver division: Simplified technique and new strategical considerations for clinical implementation in Italy

BACKGROUND

Full-right/full-left liver splitting was introduced early in the 90s as part of the great wave of technical innovations that characterized that decade. One approach was to divide the liver on the right of the Cantlie's line and leave the middle hepatic vein with the left graft, with both grafts allocated to adults. Both grafts had some functional disadvantages and exposed the adult recipients to some early hepatic dysfunction, and the results were not great. An alternative approach consisted of an ex situ division of the liver, exactly along Cantlie's line, thus sharing the middle hepatic vein between the two grafts. None of these two techniques were really adopted, and there has been nearly no transplantation of this type in the last decade worldwide.

METHOD AND RESULTS

The authors propose a variation of the latter technique that was used recently with success: The division of the liver is made simpler; the two grafts are prepared ex situ and need a simple vascular reconstruction (one venous patch on each graft); and the grafts can be implanted using very standard techniques.

CONCLUSION

Because candidates for liver transplantation weighing 25-60 kg (old children, teenagers, and some small adults) are often at some disadvantage in getting size-matched livers (this range of weight is less represented in the donor population), implementing the latter technique would help provide adequate grafts for them. In Italy, where many livers offered for splitting are not used, there would be ample room for implementing this option within the actual donor pool and allocation system.

Combined liver-kidney transplantation in pediatric patients

Combined liver-kidney transplantation (CLKT) is a surgical procedure that involves transplanting both liver and kidney organs. There are two types of CLKT: simultaneous liver-kidney transplantation (smLKT) and sequential LKT (sqLKT). CLKT accounts for a small percentage of liver transplantations (LTs), particularly in pediatric cases. Nevertheless, the procedure has demonstrated excellent outcomes, with high survival rates and lower rejection rates. The main indications for CLKT in pediatric patients differ somewhat from that in adults, in which end-stage kidney disease after LT is the major indication. In children, congenital diseases are common reason for performing CLKT; the examples of such diseases include autosomal recessive polycystic kidney disease with congenital hepatic fibrosis which equally affects both organs, and primary hyperoxaluria type 1, a primary liver disease leading kidney failure. The decision between smLKT or sqLKT depends on the dominant organ failure, the specific pathophysiology, and available organ sources. However, there remain significant surgical and societal challenges surrounding CLKT. Innovations in pharmacology and genetic engineering have decreased the necessity for CLKT in early-diagnosed cases without portal hypertension or kidney replacement therapy. Nonetheless, these advancements are not universally accessible. Therefore, decision-making algorithms should be crafted, considering region-specific organ allocation systems and prevailing medical environments.

Improving outcomes of in situ split liver transplantation in Italy over the last 25 years

BACKGROUND & AIMS

Split liver transplant(ation) (SLT) is still considered a challenging procedure that is by no means widely accepted. We aimed to present data on 25-year trends in SLT in Italy, and to investigate if, and to what extent, outcomes have improved nationwide during this time.

METHODS

The study included all consecutive SLTs performed from May 1993 to December 2019, divided into three consecutive periods: 1993-2005, 2006-2014, and 2015-2019, which match changes in national allocation policies. Primary outcomes were patient and graft survival, and the relative impact of each study period.

RESULTS

SLT accounted for 8.9% of all liver transplants performed in Italy. A total of 1,715 in situ split liver grafts were included in the analysis: 868 left lateral segments (LLSs) and 847 extended right grafts (ERGs). A significant improvement in patient and graft survival (p <0.001) was observed with ERGs over the three periods. Predictors of graft survival were cold ischaemia time (CIT) <6 h (p = 0.009), UNOS status 2b (p <0.001), UNOS status 3 (p = 0.009), and transplant centre volumes: 25-50 cases vs. <25 cases (p = 0.003). Patient survival was significantly higher with LLS grafts in period 2 vs. period 1 (p = 0.008). No significant improvement in graft survival was seen over the three periods, where predictors of graft survival were CIT <6 h (p = 0.007), CIT <6 h vs. ≥10 h (p = 0.019), UNOS status 2b (p = 0.038), and UNOS status 3 (p = 0.009). Retransplantation was a risk factor in split liver graft recipients, with significantly worse graft and patient survival for both types of graft (p <0.001).

CONCLUSIONS

Our analysis showed Italian SLT outcomes to have improved over the last 25 years. These results could help to dispel reservations regarding the use of this procedure.

IMPACT AND IMPLICATIONS

Split liver transplant(ation) (SLT) is still considered a challenging procedure and is by no means widely accepted. This study included all consecutive in situ SLTs performed in Italy from May 1993 to December 2019. With more than 1,700 cases, it is one of the largest series, examining long-term national trends in in situ SLT since its introduction. The data presented indicate that the outcomes of SLT improved during this 25-year period. Improvements are probably due to better recipient selection, refinements in surgical technique, conservative graft-to-recipient matching, and the continuous, yet carefully managed, expansion of donor selection criteria under a strict mandatory split liver allocation policy. These results could help to dispel reservations regarding the use of this procedure.

Comparative analysis of whole vs. split liver transplantation in infants

BACKGROUND

Liver transplantation (LT) in infants can be challenging due to their small size and small vasculature. Although both whole LT (WLT) and split LT (SLT) have been described in infants, the head-to-head comparison of these techniques in this population is sparse.

METHODS

We retrospectively analyzed the records of all patients with age ≤1 year at Indiana University between 2016 and 2022. All SLT were left lateral segment grafts split in situ.

RESULTS

A total of 24 infants were transplanted, with 11 SLT and 13 WLT. The median follow-up time was 52.1 months. Donor and recipient characteristics were comparable except for donor age (19 years vs. 2 years; p < .01) and weight (64 kg vs. 14.2 kg; p < .01). Early allograft dysfunction, primary nonfunction, and hepatic artery thrombosis developed more frequently in the WLT group. There were no biliary complications. There were two early deaths (2 and 4 days) in the WLT group. One-year graft survival (100% vs. 77%; p = .10) and patient survival (100% vs. 85%; p = .18) were numerically higher in the SLT group.

CONCLUSIONS

SLT with LLS offers a safe and viable option for liver transplantation in infants and is associated with a trend toward superior outcomes. SLT should be considered as a strategy to reduce waitlist times for infants in the absence of small, deceased donors for WLT.