Live Donor Liver Transplantation With Older (≥50 Years) Versus Younger (<50 Years) Donors: Does Age Matter?

Liver paired exchange: A US single-center experience-Pairs, chains, and use of compatible pairs

In the United States, the discrepancy between organ availability and need has persisted despite changes in allocation, innovations in preservation, and policy initiatives. Living donor liver transplant remains an underutilized means of improving access to timely liver transplantation and decreasing waitlist mortality. Liver paired exchange (LPE) represents an opportunity to overcome living donor liver transplant pair incompatibility due to size, anatomy, or blood type. LPE was adopted as a strategy to augment access to liver transplantation at our institution. Specific educational materials, consent forms, and selection processes were developed to facilitate LPE. From 2019 through October 2023, our center performed 11 LPEs, resulting in 23 living donor liver transplant pairs. The series included several types of LPE: those combining complementary incompatible pairs, the inclusion of compatible pairs to overcome incompatibility, and the use of altruistic nondirected donors to initiate chains. These exchanges facilitated transplantation for 23 recipients, including 1 pediatric patient. LPE improved access to liver transplantation at our institution. The ethical application of LPE includes tailored patient education, assessment and disclosure of exchange balance, mitigation of risk, and maximization of benefit for donors and recipients.

Future of U.S. living donor liver transplant: Donor and recipient criteria, transplant indications, transplant oncology, liver paired exchange, and non-directed donor graft allocation

In the United States, living donor liver transplant (LDLT), from both directed and nondirected living donors, has expanded over the past several years. LDLT is viewed as an important opportunity to expand the overall donor pool for liver transplantation (LT), shorten waiting times for a life-prolonging LT surgery, and reduce LT waitlist mortality. The LT community's focus on LDLT expansion in the United States is fostering discussions around future opportunities, which include the safe expansion of donor and recipient candidate eligibility criteria, broadening indications for LDLT including applications in transplant oncology, developing national initiatives around liver paired exchange, and maintaining vigilance to living donor and recipient candidate risk/benefit equipoise. Potential opportunities for expanding living liver donor and recipient candidate criteria include using donors with more than minimal hepatic steatosis, evaluating older donors, performing LDLT in older recipients to facilitate timely transplantation, and providing candidates who would benefit from an LT, but may otherwise have limited access (ie, lower MELD scores), an avenue to receive a life-prolonging organ. Expansion opportunities for LDLT are particularly robust in the transplant oncology realm, including leveraging LDLT for patients with advanced HCC beyond Milan, intrahepatic cholangiocarcinoma, and nonresectable colorectal cancer liver metastases. With ongoing investment in the deliberate growth of LDLT surgical expertise, experience, and technical advances in the United States, the LT community's future vision to increase transplant access to more patients with end-stage liver disease and selected oncology patients may be successfully realized.

Utilization of older deceased donors for pediatric liver transplant may negatively impact long-term survival

BACKGROUND

Multiple adult studies have investigated the role of older donors (ODs) in expanding the donor pool. However, the impact of donor age on pediatric liver transplantation (LT) has not been fully elucidated.

METHODS

UNOS database was used to identify pediatric (≤18 years) LTs performed in the United States during 2002-22. Donors ≥40 years at donation were classified as older donors (ODs). Propensity analysis was performed with 1:1 matching for potentially confounding variables.

RESULTS

A total of 10,024 pediatric liver transplantation (PLT) patients met inclusion criteria; 669 received liver grafts from ODs. Candidates receiving OD liver grafts were more likely to be transplanted for acute liver failure, have higher Model End-Stage Liver Disease/Pediatric End-Stage Liver Disease (MELD/PELD) scores at LT, listed as Status 1/1A at LT, and be in the intensive care unit (ICU) at time of LT (all p < 0.001). Kaplan-Meier (KM) analyses showed that recipients of OD grafts had worse patient and graft survival (p < 0.001) compared to recipients of younger donor (YD) grafts. KM analyses performed on candidates matched for acuity at LT revealed inferior patient and graft survival in recipients of deceased donor grafts (p < 0.001), but not living donor grafts (p > 0.1) from ODs. Cox regression analysis demonstrated that living donor LT, diagnosis of biliary atresia and first liver transplant were favorable predictors of recipient outcomes, whereas ICU stay before LT and transplantation during 2002-12 were unfavorable.

CONCLUSION

Livers from ODs were used for candidates with higher acuity. Pediatric recipients of livers from ODs had worse outcome compared to YDs; however, living donor LT from ODs had the least negative impact on recipient outcomes.

Survival after LDLT in recipients ≥70 years old in the United States. An OPTN/UNOS liver transplant registry analysis

BACKGROUND

Living donor liver transplantation (LDLT) in the elderly population is currently not well studied. There are single-center studies indicating that patient age should not be a barrier to LDLT, with similar outcomes compared to younger recipients.

METHODS

Using UNOS/STAR data from 2010 to 2022 we retrospectively analyzed patients ≥70 years old receiving a living donor graft (LDLT ≥70y group) versus a deceased donor graft (DDLT ≥70y group). In addition, we compared recipients ≥70 years old undergoing LDLT versus patients 18-69 years old also undergoing LDLT. Donor and recipient baseline characteristics, as well as postoperative outcomes including graft and patient survival were analyzed and compared between groups.

RESULTS

Recipients in the LDLT ≥70y group showed less disease burden and spent significantly less time on the waitlist when compared to recipients in the DDLT ≥70y group (102 [49-201] days versus 170 [36-336] days) respectively; p = .004. With the exception of a longer length of stay (LOS) in the LDLT ≥70y group (p ≤ .001), postoperative outcomes were comparable with recipients in the DDLT ≥70y group, including similar graft and patient survival rates at 1-, 3-, and 5-years. When compared to younger recipients of a graft from a living donor, patients in the LDLT ≥70y group had similar post-transplant functional status, re-transplant rates and similar causes contributing to graft failure. However, significantly lower graft and patient survival rates were observed.

CONCLUSION

LDLT for recipients aged 70 or greater represents a faster access to transplantation in a safe and feasible manner when compared to similar- aged recipients undergoing DDLT.

Impact of Older Donor Age on Recipient and Graft Survival After LDLT: The US Experience

BACKGROUND

The impact of selecting older donors for living donor liver transplantation (LDLT) in the United States is incompletely studied, particularly in light of the recent expansion of LDLT nationally.

METHODS

Adult LDLTs from January 01, 2005 to December 31, 2019 were identified using the United Network for Organ Sharing database. Multivariable Cox models evaluated living donor (LD) age as a predictor of LDLT recipient and graft survival. The impact of increasing donor age on recipient outcomes was compared between LD and deceased donor recipients. Donor postoperative outcomes were evaluated.

RESULTS

There were 3539 LDLTs at 65 transplant centers during the study period. Despite the recent expansion of LDLT, the proportion of LDs aged ≥50 y was stable. There were no clinically significant differences in recipient or donor characteristics by LD age group. LD age ≥50 y was associated with an adjusted hazard ratio of 1.49 ( P = 0.012) for recipient survival and 1.61 ( P < 0.001) for graft survival (vs LDs aged 18-29 y). The negative impact of increasing donor age on graft survival was more profound after LDLT than deceased donor liver transplantation (interaction P = 0.019). There was a possible increased rate of early donor biliary complications for donors >55 y (7.1% versus 3.1% for age <40 y; P = 0.156).

CONCLUSIONS

Increasing LD age is associated with decreased recipient and graft survival, although older donors still largely yield acceptable outcomes. Donor outcomes were not clearly impacted by increasing age, though this warrants further study.

When is it safe for the liver donor to be discharged home and prevent unnecessary re-hospitalizations? - A systematic review of the literature and expert panel recommendations

BACKGROUND

Few data are available on discharge criteria after living liver donation (LLD).

OBJECTIVES

To identify the features for fit for discharge checklist after LLD to prevent unnecessary re-hospitalizations and to provide international expert recommendations.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. The critical outcomes included were complications rates and liver function (defined by elevated bilirubin and INR) (CRD42021260725).

RESULTS

Total 57/1710 studies were included in qualitative analysis and 28/57 on the final analysis. No randomized controlled trials were identified. The complications rate was reported in 20/28 studies and ranged from 7.8% to 71.2%. Post hepatectomy liver function was reported in 13 studies. The Quality of Evidence (QoE) was Low and Very-Low for complications rate and liver function test, respectively.

CONCLUSIONS

Monitoring and prevention of donor complications should be crucial in decision making of discharge. Pain and diet control, removal of all drains and catheters, deep venous thrombosis prophylaxis, and use routine imaging (CT scan or liver ultrasound) before discharge should be included as fit for discharge checklist (QoE; Low | GRADE of recommendation; Strong). Transient Impaired liver function (defined by elevated bilirubin and INR), a prognostic marker of outcome after liver resection, usually occurs after donor right hepatectomy and should be monitored. Improving trends for bilirubin and INR value should be observed by day 5 post hepatectomy and be included in the fit for discharge checklist. (QoE; Very-Low | GRADE; Strong).

Up-regulated LRRN2 expression as a marker for graft quality in living donor liver transplantation

The quality and size of liver grafts are critical factors that influence living‐donor liver transplantation (LDLT) function and safety. However, the biomarkers used for predicting graft quality are lacking. In this study, we sought to identify unique graft quality markers, aside from donor age, by using the livers of non‐human primates. Hepatic gene microarray expression data from young and elderly cynomolgus macaques revealed a total of 271 genes with significantly increased expression in the elderly. These candidate genes were then narrowed down to six through bioinformatics analyses. The expression patterns of these candidate genes in human donor liver tissues were subsequently examined. Importantly, we found that grafts exhibiting up‐regulated expression of these six candidate genes were associated with an increased incidence of liver graft failure. Multivariable analysis further revealed that up‐regulated expression of LRRN2 (encoding leucine‐rich repeat protein, neuronal 2) in donor liver tissue served as an independent risk factor for graft failure (odds ratio 4.50, confidence interval 2.08–9.72). Stratification based on graft expression of LRRN2 and donor age was also significantly associated with 6‐month graft survival rates. Conclusion: Up‐regulated LRRN2 expression of liver graft is significantly correlated with graft failure in LDLT. In addition, combination of graft LRRN2 expression and donor age may represent a promising marker for predicting LDLT graft quality.

Impact of Donor and Recipient Age on Outcomes After Living Donor Liver Transplant

BACKGROUND

Living donor liver transplant between elderly donors and recipients has gained popularity, but the effects of their age remain unknown. Our aim is to evaluate the effects of matching by donor and recipient age with special insights into their recovery periods.

METHODS

Ninety-five living donor liver transplant pairs, excluding the left lateral segment graft cases, who underwent surgery were enrolled. Median follow-up was 97 months (range, 1-212 months). Elderly recipients were classified as being 51 years or older. Donor-recipient pairs were divided into (1) nonelderly donor/nonelderly recipient (YY) (n = 26), (2) elderly donor/nonelderly recipient (n = 8), (3) nonelderly donor/elderly recipient (n = 38), and (4) elderly donor/elderly recipient (EE) (n = 23).

RESULTS

The 1-, 3-, and 5-year survival rates were 92.7%, 92.7%, and 88.9% (YY); 75.0%, 62.5%, and 62.5% (EY); 80.5%, 76.3%, and 67.9% (EY); and 86.9%, 82.6%, and 78.1% (EE) (P = .30), respectively. Perioperative parameters were comparable between the 4 groups. Liver grafts from the elderly population exhibited higher peaks of transaminases post-transplant regardless of recipient age (P ≤ .05). Postoperative recovery of total bilirubin in the EE group was relatively slower (P = .27). Required rates of plasma exchange postoperatively were relatively higher in the EE group (34.8% vs 15.4% in the YY group).

CONCLUSIONS

These findings suggest a modest and not statistically significant effect that elderly liver grafts exhibit slower recovery trajectories in the acute phase but finally achieve acceptable outcomes.

Which is better to use "body weight" or "standard liver weight", for predicting small-for-size graft syndrome after living donor liver transplantation?

AIM

Little evidence about whether to apply graft-to-recipient body weight ratio (GRWR) or graft weight to standard liver weight (GW/SLW) for graft selection has been published. The aim of the present study was to clarify the importance of the correct use of GRWR and GW/SLW for selecting graft according to the recipients' physique in living donor liver transplantation (LDLT).

METHODS

Data were collected for 694 recipients who underwent LDLT between 1997 and 2020.

RESULTS

One of the marginal grafts meeting GW/SLW ≥ 35% but GRWR < 0.7% has been used in more recipients with men and higher body mass index (BMI), and the other meeting GRWR ≥ 0.7% but GW/SLW < 35% has been used in more recipients with women with lower BMI. In the cohort of BMI > 30 kg/m2, the recipients with GRWR < 0.7% had a significantly higher incidence of small-for-size graft syndrome (SFSS) compared to those with GRWR ≥ 0.7% (P = 0.008, 46.2% vs 5.9%), and using the cutoff of GW/SLW < 35% could not differentiate. In contrast, in the cohort of BMI ≤ 30 kg/m2, the recipients with GW/SLW < 35% also had a significantly higher incidence of SFSS (P = 0.013, 16.9% vs 9.4%). Multivariate analysis showed that GRWR < 0.7% [odds ratio (OR) 14.145, P = 0.048] was the independent risk factor for SFSS in obese recipients, and GW/SLW < 35% [OR 2.685, P = 0.002] was the independent risk factor in non-obese recipients.

CONCLUSION

Proper use of the formulas for calculating GRWR and GW/SLW in choosing graft according to recipient BMI is important, not only to meet metabolic demand for avoiding SFSS but also to ameliorate donor shortages.

Living-donor liver transplantation: Right versus left

A dilemma of graft selection between right or left livers occurs during the planning of living-donor liver transplantation (LDLT) as well as splitting a whole liver graft into full right/full left grafts in deceased-donor liver transplantation. The right liver's relation to the whole liver could be considered as the trunk of a tree; it has a larger volume, the main axis of bile ducts, and the inferior vena cava mainly belongs to the right liver. Therefore, it was considered as the standard graft in LDLTs. Whether to procure the middle hepatic vein (MHV) with a right liver graft or to leave it attached to the left-liver remnant largely depends on the transplant institute. Recently, most transplant institutes tend to leave the MHV with the left liver for the sake of donor safety. Unlike hepatectomy for liver tumors, it is vital to preserve inflow and outflow for both the resected as well as the remaining livers. While procuring any graft type, the most important is to procure a liver graft with reconstructable portal veins, hepatic arteries, hepatic veins, and bile ducts, which should be well preoperatively planned using 3D-computed tomography with considerations given to graft volume and potential congestion areas.

Renal Dysfunction After Liver Transplantation: Effect of Donor Type

Recipients of donation after circulatory death (DCD) grafts are reportedly at higher risk of developing renal dysfunction after liver transplantation (LT). We compared the development of acute kidney injury (AKI) and chronic kidney disease (CKD) after LT in recipients of DCD versus donation after brain death (DBD) or living donor liver transplantation (LDLT) livers. Adult recipients of DBD, LDLT, and DCD between 2012 and 2016 at Toronto General Hospital were included. AKI was defined as a post-LT increase of serum creatinine (sCr) ≥26.5 µmol/L within 48 hours or a ≥50% increase from baseline, and CKD was defined as an estimated glomerular filtration rate <60 mL/minute for >3 months. A total of 681 patients (DCD, n = 57; DBD, n = 446; and LDLT, n = 178) with similar baseline comorbidities were included. Perioperative AKI (within the first 7 postoperative days) was observed more frequently in the DCD group (61%; DBD, 40%; and LDLT, 44%; P = 0.01) and was associated with significantly higher peak AST levels (P < 0.001). Additionally, patients in the DCD group had a significantly higher peak sCr (P < 0.001) and a trend toward higher rates of AKI stage 3 (DCD, 33%; DBD, 21%; LDLT, 21%; P = 0.11). The proportions of recovery from AKI (DCD, 77%; DBD, 72%; LDLT, 78%; P = 0.45) and patients developing CKD (DCD, 33%; DBD, 32%; LDLT, 32%; P = 0.99) were similar. Nevertheless, patients who received DCD or DBD LT and required perioperative renal replacement therapy showed significantly lower patient survival in multivariate analysis (hazard ratio, 7.90; 95% confidence interval, 4.51-13.83; P < 0.001). In conclusion, recipients of DCD liver grafts experience higher rates of short-term post-LT renal dysfunction compared with DBD or LDLT. Additional risk factors for the development of severe kidney injury, such as high Model for End-Stage Liver Disease score, massive transfusions, or donor age ≥60 years should be avoided.

Living donor liver transplantation

PURPOSE OF REVIEW

As experience grows, living donor liver transplantation (LDLT) has become an effective treatment option to overcome the deceased donor organ shortage.

RECENT FINDINGS

Donor safety is the highest priority in LDLT. Strict donor selection according to structured protocols and center experience are the main factors that determine donor safety. However, with increased experience, many centers have explored increasing organ availability within living donation by means of ABO incompatible LDLT, dual graft LDLT, and anonymous living donation. Also, this growing experience in LDLT has allowed the transplant community to cautiously explore the role of liver transplantation for hepatocellular carcinoma outside of Milan criteria and patients with unresectable colorectal liver metastases.

SUMMARY

LDLT has become established as a viable strategy to ameliorate the organ shortage experienced by centers around the world. Improved understanding of this technique has allowed the improved utilization of live donor graft resources, without compromising donor safety. Moreover, LDLT may offer some advantages over deceased donor liver transplantation and a unique opportunity to assess the broader applicability of liver transplantation.

Pediatric living donor liver transplantation with large-for-size left lateral segment grafts

Usage of "large-for-size" left lateral segment (LLS) liver grafts in children with high graft to recipient weight ratio (GRWR) is controversial due to concerns about increased recipient complications. During the study period, 77 pediatric living donor liver transplantations (LDLTs) with LLS grafts were performed. We compared recipients with GRWR ≥2.5% (GR-High = 50) vs GRWR <2.5% (GR-Low = 27). Median age was higher in the GR-Low group (40 vs 8 months, P> .0001). Graft (GR-High: 98%, 98%, 98% vs GR-Low: 96%, 93%, 93%) and patient (GR-High: 98%, 98%, 98% vs GR-Low: 100%, 96%, 96%) survival at 1, 3, and 5 years was similar between groups (P = NS). Overall complications were also similar (34% vs 30%; P = .8). Hepatic artery and portal vein thrombosis following transplantation was not different (P = NS). Delayed abdominal fascia closure was more common in GR-High patients (17 vs 1; P = .002). Subgroup analysis comparing recipients with GRWR ≥4% (GR-XL = 20) to GRWR <2.5% (GRWR-Low = 27) revealed that delayed abdominal fascia closure was more common in the GR-XL group, but postoperative complications and graft and patient survival were similar. We conclude that pediatric LDLT with large-for-size LLS grafts is associated with excellent clinical outcomes. There is an increased need for delayed abdominal closure with no compromise of long-term outcomes. The use of high GRWR expands the donor pool and improves timely access to the benefits of transplantation without extra risks.

Conceptual changes in small-for-size graft and small-for-size syndrome in living donor liver transplantation

Early series in living donor liver transplantation (LDLT) in adults demonstrated a lower safe limit of graft volume standard liver volume ratio 25%–45%. A subsequent worldwide large LDLT series proposed a 0.8 graft recipient weight ratio (GRWR) to define small-for-size graft (SFSG) in adult LDLT. Thereafter, researchers identified innate and inevitable factors including changes in liver volume during imaging studies and graft shrinkage due to perfusion solution. Although the definition of small-for-size syndrome (SFSS) advocated in the 2000s was mainly based on prolonged cholestasis and ascites output, the term SFSS was inadequate to describe clinical manifestations possibly caused by multiple factors. Thus, the term “early allograft dysfunction (EAD),” characterized by total bilirubin >10 mg/dL or coagulopathy with international normalized ratio >1.6 on day 7, has become prevalent to describe graft dysfunction including SFSS after LDLT. Although various efforts have been made to overcome EAD in LDLT, graft selection to maintain an expected GRWR >0.8 and full venous drainage, as well as inflow modulation using splenic artery ligation, have become standard in recent LDLT.

Donor outcomes in anonymous live liver donation

BACKGROUND & AIMS

Death rates on liver transplant waiting lists range from 5%-25%. Herein, we report a unique experience with 50 anonymous individuals who volunteered to address this gap by offering to donate part of their liver to a recipient with whom they had no biological connection or prior relationship, so called anonymous live liver donation (A-LLD).

METHODS

Candidates were screened to confirm excellent physical, mental, social, and financial health. Demographics and surgical outcomes were analyzed. Qualitative interviews after donation examined motivation and experiences. Validated self-reported questionnaires assessed personality traits and psychological impact.

RESULTS

A total of 50 A-LLD liver transplants were performed between 2005 and 2017. Most donors had a university education, a middle-class income, and a history of prior altruism. Half were women. Median age was 38.5 years (range 20-59). Thirty-three (70%) learned about this opportunity through public or social media. Saving a life, helping others, generativity, and reciprocity for past generosity were motivators. Social, financial, healthcare, and legal support in Canada were identified as facilitators. A-LLD identified most with the personality traits of agreeableness and conscientiousness. The median hospital stay was 6 days. One donor experienced a Dindo-Clavien Grade 3 complication that completely resolved. One-year recipient survival was 91% in 22 adults and 97% in 28 children. No A-LLD reported regretting their decision.

CONCLUSIONS

This is the first and only report of the characteristics, motivations and facilitators of A-LLD in a large cohort. With rigorous protocols, outcomes are excellent. A-LLD has significant potential to reduce the gap between transplant organ demand and availability.

LAY SUMMARY

We report a unique experience with 50 living donors who volunteered to donate to a recipient with whom they had no biological connection or prior relationship (anonymous living donors). This report is the first to discuss motivations, strategies and facilitators that may mitigate physical, social and ethical risk factors in this patient population. With rigorous protocols, anonymous liver donation and recipient outcomes are excellent; with appropriate clinical expertise and system facilitators in place, our experience suggests that other centers may consider the procedure for its significant potential to reduce the gap between transplant organ demand and availability.

Older Donor Age Is a Risk Factor for Negative Outcomes After Adult Living Donor Liver Transplantation Using Small-for-Size Grafts

Adult-to-adult living donor liver transplantation (ALDLT) using small-for-size grafts (SFSGs), ie, a graft with a graft-to-recipient weight ratio (GRWR) <0.8%, has been a challenge that should be carefully dealt with, and risk factors in this category are unclear. Therefore, we aimed to examine the risk factors and outcomes of ALDLT using SFSGs over a 13-year period in 121 patients who had undergone their first ALDLT using SFSGs. Small-for-size syndrome (SFSS), early graft loss, and 1-year mortality were encountered in 21.6%, 14.9%, and 18.4% of patients, respectively. By multivariate analysis, older donor age (≥45 years) was an independent risk factor for SFSS (odds ratio [OR], 4.46; P = 0.004), early graft loss (OR, 4.11; P = 0.02), and 1-year mortality (OR, 3.76; P = 0.02). Child-Pugh C class recipients were associated with a higher risk of SFSS development (P = 0.013; OR, 7.44). Despite no significant difference between GRWR categories in the multivariate outcome analysis of the whole population, in the survival analysis of the 2 donor age groups, GRWR <0.6% was associated with significantly lower 1-year survival than the other GRWR categories in the younger donor group. Moreover, in the high final portal venous pressure (PVP) group (>15 mm Hg), younger ABO-compatible donors showed 100% 1-year survival with a significant difference from the group of other donors. Older donor age was an independent risk factor for SFSS, early graft loss, and 1-year mortality after ALDLT using SFSGs. GRWR should not be <0.6%, and PVP modulation is indicated when grafts from older or ABO-incompatible donors are used.

Age and liver transplantation

The average age of liver transplant donors and recipients has increased over the years. Independent of the cause of liver disease, older candidates have more comorbidities, higher waitlist mortality and higher post-transplant mortality than younger patients. However, transplant benefit may be similar in older and younger recipients, provided older recipients are carefully selected. The cohort of elderly patients transplanted decades ago is also increasingly raising issues concerning long-term exposure to immunosuppression and aging of the transplanted liver. Excellent results can be achieved with elderly donors and there is virtually no upper age limit for donors after brain death liver transplantation. The issue is how to optimise selection, procurement and matching to ensure good results with elderly donors. The impact of old donor age is more pronounced in younger recipients and patients with a high model for end-stage liver disease score. Age matching between the donor and the recipient should be incorporated into allocation policies with a multistep approach. However, age matching may vary depending on the objectives of different allocation policies. In addition, age matching must be revisited in the era of direct-acting antivirals. More restrictive limits have been adopted in donation after circulatory death. Perfusion machines which are currently under investigation may help expand these limits. In living donor liver transplantation, donor age limit is essentially guided by morbidity related to procurement. In this review we summarise changing trends in recipient and donor age. We discuss the implications of older age donors and recipients. We also consider different options for age matching in liver transplantation that could improve outcomes.

Current Status of Living Donor Liver Transplantation in the United States

Adult-to-adult living donor liver transplantation (LDLT) was introduced in response to the shortage of deceased donor liver grafts. The number of adult living donor transplants is increasing due to improved outcomes and increasing need. Advantages of LDLT include optimization of the timing of transplant, better organ quality, and lower rates of recipient mortality compared to staying on the wait list for deceased donor liver transplant. Donor safety remains the major focus when considering LDLT. Recent advancements have supported the increased use of LDLT to help decrease wait list death and improve long-term survival of transplant recipients.

Living Donor Liver Transplantation Using Selected Grafts With 2 Bile Ducts Compared With 1 Bile Duct Does Not Impact Patient Outcome

The outcome after living donor liver transplantation (LDLT) using grafts with multiple bile ducts (BDs) remains unclear. We analyzed 510 patients who received an adult-to-adult right lobe LDLT between 2000 and 2015 and compared outcome parameters of those receiving grafts with 2 BDs (n = 169) with patients receiving grafts with 1 BD (n = 320). Additionally, patients receiving a graft with 3 BDs (n = 21) were analyzed. Demographic variables and disease severity were similar between the groups. Roux-en-Y reconstruction was significantly more common in the 2 BD group (77% versus 38%; P < 0.001) compared with the 1 BD group. No difference was found in biliary complication rates within 1 year after LDLT (1 BD versus 2 BD groups, 18% versus 21%, respectively; P = 0.46). In the 2 BD group, 82/169 (48.5%) patients were reconstructed with 2 anastomoses. The number of anastomoses did not negatively impact biliary complication rates. Recipients' major complication rate (Clavien ≥ 3b) was similar between both groups (1 BD versus 2 BD groups, 21% versus 24%, respectively; P = 0.36). Furthermore, no difference could be found between the 1 BD, the 2 BD, and the 3 BD groups in the frequency of developing biliary complications within 1 year (18%, 21%, 14%, respectively; P = 0.64), BD strictures (15%, 15%, 5%, respectively; P = 0.42), or BD leaks (10%, 11%, 10%, respectively; P = 0.98). In addition, the 1-year (90% versus 91%), 5-year (82% versus 77%), and 10-year (70% versus 66%) graft survival rates as well as the 1-year (92% versus 93%), 5-year (84% versus 80%), and 10-year (75% versus 76%) patient survival rates were comparable between the 1 BD and the 2 BD groups (P = 0.41 and P = 0.54, respectively). In conclusion, this study demonstrates that selected living donor grafts with 2 BDs can be used safely without negatively impacting biliary complication rates and graft or patient survival rates.

Donor biomarkers as predictors of organ use and recipient survival after neurologically deceased donor organ transplantation

PURPOSE

We sought to build prediction models for organ transplantation and recipient survival using both biomarkers and clinical information.

MATERIALS AND METHODS

We abstracted clinical variables from a previous randomized trial (n = 556) of donor management. In a subset of donors (n = 97), we measured two candidate biomarkers in plasma at enrollment and just prior to explantation.

RESULTS

Secretory leukocyte protease inhibitor (SLPI) was significant for predicting liver transplantation (C-statistic 0.65 (0.53, 0.78)). SLPI also significantly improved the predictive performance of a clinical model for liver transplantation (integrated discrimination improvement (IDI): 0.090 (0.009, 0.210)). For other organs, clinical variables alone had strong predictive ability (C-statistic >0.80). Recipient 3-years survival was 80.0% (71.9%, 87.0%). Donor IL-6 was significantly associated with recipient 3-years survival (adjusted Hazard Ratio (95%CI): 1.26(1.08, 1.48), P = .004). Neither clinical variables nor biomarkers showed strong predictive ability for 3-year recipient survival.

CONCLUSIONS

Plasma biomarkers in neurologically deceased donors were associated with organ use. SLPI enhanced prediction within a liver transplantation model, whereas IL-6 before transplantation was significantly associated with recipient 3-year survival. Clinicaltrials.gov: NCT00987714.

Feasibility of using marginal liver grafts in living donor liver transplantation

Liver transplantation (LT) is one of the most effective treatments for end-stage liver disease caused by related risk factors when liver resection is contraindicated. Additionally, despite the decrease in the prevalence of hepatitis B virus (HBV) over the past two decades, the absolute number of HBsAg-positive people has increased, leading to an increase in HBV-related liver cirrhosis and hepatocellular carcinoma. Consequently, a large demand exists for LT. While the wait time for patients on the donor list is, to some degree, shorter due to the development of living donor liver transplantation (LDLT), there is still a shortage of liver grafts. Furthermore, recipients often suffer from emergent conditions, such as liver dysfunction or even hepatic encephalopathy, which can lead to a limited choice in grafts. To expand the pool of available liver grafts, one option is the use of organs that were previously considered “unusable” by many, which are often labeled “marginal” organs. Many previous studies have reported on the possibilities of using marginal grafts in orthotopic LT; however, there is still a lack of discussion on this topic, especially regarding the feasibility of using marginal grafts in LDLT. Therefore, the present review aimed to summarize the feasibility of using marginal liver grafts for LDLT and discuss the possibility of expanding the application of these grafts.

Living Donor Liver Transplantation: Technical Innovations

Living donor liver transplantation (LDLT) has found a place to serve the end-stage liver disease community as the donor safety and recipient suitability has been elucidated. Donor safety is of paramount importance and transplant programs must continue endeavors to maintain the highest possible standards. At the same time, adequacy of grafts based on recipient clinical status via their model for end-stage liver disease (MELD) score and volumetric studies to achieve a GRBWR >0.8, along with special attention to anatomic tailoring and portal venous flow optimization are necessary for successful transplantation. Technical innovations have improved sequentially the utility and availability of LDLT.

Expanding the donor pool: Donation after circulatory death and living liver donation do not compromise the results of liver transplantation

Because of the shortfall between the number of patients listed for liver transplantation (LT) and the available grafts, strategies to expand the donor pool have been developed. Donation after circulatory death (DCD) and living donor (LD) grafts are not universally used because of the concerns of graft failure, biliary complications, and donor risks. In order to overcome the barriers for the implementation of using all 3 types of grafts, we compared outcomes after LT of DCD, LD, and donation after brain death (DBD) grafts. Patients who received a LD, DCD, or DBD liver graft at the University of Toronto were included. Between January 2009 through April 2017, 1054 patients received a LT at our center. Of these, 77 patients received a DCD graft (DCD group); 271 received a LD graft (LD group); and 706 received a DBD graft (DBD group). Overall biliary complications were higher in the LD group (11.8%) compared with the DCD group (5.2%) and the DBD group (4.8%; P < 0.001). The 1-, 3-, and 5-year graft survival rates were similar between the groups with 88.3%, 83.2%, and 69.2% in the DCD group versus 92.6%, 85.4%, and 84.7% in the LD group versus 90.2%, 84.2%, and 79.9% in the DBD group (P = 0.24). Furthermore, the 1-, 3-, and 5-year patient survival was comparable, with 92.2%, 85.4%, and 71.6% in the DCD group versus 95.2%, 88.8%, and 88.8% in the LD group versus 93.1%, 87.5%, and 83% in the DBD group (P = 0.14). Multivariate Cox regression analysis revealed that the type of graft did not impact graft survival. In conclusion, DCD, LD, and DBD grafts have similar longterm graft survival rates. Increasing the use of LD and DCD grafts may improve access to LT without affecting graft survival rates. Liver Transplantation 24 779-789 2018 AASLD.

Right lobe living donors ages 55 years old and older in liver transplantation

The evidence is insufficient for safe use of elderly donors in adult-to-adult living donor liver transplantation (LDLT). The aim of this study was to evaluate the outcomes of right lobe LDLT by donor age (≥55 versus < 55 years). All living donors who underwent right hepatectomy at the authors' institution between March 2008 and December 2015 were divided into 2 groups: group A with an age ≥ 55 years and group B with an age of <55 years. The selection criteria for elderly donor were preservation of middle hepatic vein, remnant liver volume ≥30%, and no or mild fatty liver. The matching criteria of recipients for the elderly donor grafts were Model for End-Stage Liver Disease score of <25, graft-to-recipient weight ratio of >0.8%, and body mass index of <25 kg/m² . Perioperative data, complications by the Clavien classification, and the outcomes with at least 12 months follow-up were compared. A total of 42 donors were enrolled in group A and 498 in group B. No significant differences in operative parameters were observed between the 2 groups. The peak postoperative aspartate aminotransferase, alanine aminotransferase, and total bilirubin levels made no difference between the 2 groups. The peak international normalized ratio level was significantly lower in group A than in group B (P = 0.001). All donors recovered completely with no significant differences in overall complications between the 2 groups. All recipients of grafts from donors in group A showed good initial function with no significant differences in 1-year graft and patient survival or biliary complications between 2 groups. These results provide clinical evidence for feasibility of right hepatectomy in living donors aged ≥ 55 years without compromising donor safety or recipient outcomes. Liver Transplantation 23 1305-1311 2017 AASLD.

Donor BMI >30 Is Not a Contraindication for Live Liver Donation

The increased prevalence of obesity worldwide threatens the pool of living liver donors. Although the negative effects of graft steatosis on liver donation and transplantation are well known, the impact of obesity in the absence of hepatic steatosis on outcome of living donor liver transplantation (LDLT) is unknown. Consequently, we compared the outcome of LDLT using donors with BMI <30 versus donors with BMI ≥30. Between April 2000 and May 2014, 105 patients received a right-lobe liver graft from donors with BMI ≥30, whereas 364 recipients were transplanted with grafts from donors with BMI <30. Liver steatosis >10% was excluded in all donors with BMI >30 by imaging and liver biopsies. None of the donors had any other comorbidity. Donors with BMI <30 versus ≥30 had similar postoperative complication rates (Dindo-Clavien ≥3b: 2% vs. 3%; p = 0.71) and lengths of hospital stay (6 vs. 6 days; p = 0.13). Recipient graft function, assessed by posttransplant peak serum bilirubin and international normalized ratio was identical. Furthermore, no difference was observed in recipient complication rates (Dindo-Clavien ≥3b: 25% vs. 20%; p = 0.3) or lengths of hospital stay between groups. We concluded that donors with BMI ≥30, in the absence of graft steatosis, are not contraindicated for LDLT.

Current challenges and future directions for liver transplantation

Liver transplantation is an effective and widely used therapy for several patients with acute and chronic liver diseases. The discrepancy between the number of patients on the waiting list and available donors remains the key issue and is responsible for the high rate of waiting list mortality. The recent news is that the majority of patients with hepatitis C virus related liver disease will be cured by new antivirals therefore we should expect soon a reduction in the need of liver transplantation for these recipients. This review aims to highlight, in two different sections, the main open issues of liver transplantation concerning the current and future strategies to the best use of limited number of organs. The first section cover the strategies to increase the donor pool, discussing the use of older donors, split grafts, living donation and donation after cardiac death and mechanical perfusion systems to improve the preservation of organs before liver transplantation. Challenges in immunosuppressive therapy and operational tolerance induction will be evaluated as potential tools to increase the survival in liver transplant recipients and to reducing the need of re-transplantation. The second section is devoted to the evaluation of possible new indications to liver transplantation, where the availability of organs by implementing the strategies mentioned in the first section and the reduction in the number of waiting transplants for HCV disease is realized. Among these new potential indications for transplantation, the expansion of the Milan criteria for hepatocellular cancer is certainly the most open to question.

Adult to adult right lobe living donor liver transplantation: does biological relationship matter?

The influence of the biological relationship between the donor and the recipient is rarely discussed in living donor liver transplantation (LDLT), although it is believed to be an important risk factor in other types of organ transplantations. A total of 272 consecutive patients undergoing adult to adult right lobe LDLT were retrospectively analyzed and stratified into a nonbiologically related (NBR) group (69 patients) and a biologically related (BR) group (203 patients). The preoperative data and postoperative outcomes of both recipients and donors were evaluated.More than two-thirds of the recipients had histories of HBV infection, and hepatocellular carcinoma (HCC) was the main reason for the patients undergoing LDLT in both groups. The percentage of female donors in the NBR group was more than the percentage in the BR group (P = 0.000). There were no differences between the groups in postoperative laboratory testing or daily immunosuppression dose, and the complication rates in both the recipient and donor surgeries showed no significant differences. For patients with benign diseases, the cumulative 1-, 3-, 5-, and 10-year survival rate were 92.9% in the 4 periods in the NBR group and 89.1%, 87.6%, 83.7%, and 83.7%, respectively, in BR group, while for the patients diagnosed as HCC, if patients exceeding the Milan criteria were involved, the 5-year survival rate was 41.2%, compared to 82% for patients within the Milan criteria, which was nearly the same as for those with the benign disease. In conclusion, our findings suggested that the biological relationship between the donor and the recipient in adult to adult LDLT was not associated with the short- and long-term outcomes of recipients diagnosed with benign liver diseases and early stage HCC. Moreover, the criteria for patients diagnosed with HCC to undergo LDLT should be restrictively selected.

Recent advances in understanding and managing liver transplantation

Liver transplantation (LT) has been established as the most effective treatment modality for end-stage liver disease over the last few decades. Currently, patient and graft survival after LT are excellent, with 1- and 5-year survival of 90% and 80%, respectively. However, the timing of referral to LT is crucial for improving survival benefit and outcome. The current shortage of donors and the increasing demand for LT currently lengthen the waiting time. Thus, waiting list mortality is about 10–15%, according to the geographical area. For this reason, over the last several years, alternatives to deceased donor LT and new options for prioritizing patients on the waiting list have been proposed.