Outcomes of donor evaluation in adult-to-adult living donor liver transplantation

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.

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.

Enhanced Role of Multi-Pair Donor Swaps in Response to Size Incompatibility: The First Two 5-Way and the First 6-Way Liver Paired Exchanges

A significant portion of liver transplantations in many countries is conducted via living-donor liver transplantation (LDLT). However, numerous potential donors are unable to donate to their intended recipients due to factors such as blood-type incompatibility or size incompatibility. Despite this, an incompatible donor for one recipient may still be a viable donor for another patient. In recent decades, several transplant centers have introduced liver paired exchange (LPE) programs, facilitating donor exchanges between patients and their incompatible donors, thereby enabling compatible transplants. Initially, LPE programs in Asia primarily involved ABO-i pairs, resulting in 2-way exchanges mainly between blood-type A and B recipients and donors. This practice has led to a modest 1-2% increase in LDLTs at some centers. Incorporating size incompatibility alongside blood-type incompatibility further enhances the efficacy and significance of multiple-pair LPEs. Launched in July 2022, a single-center LPE program established at Inönü University Liver Transplant Institute in Malatya, Türkiye, has conducted thirteen 2-way, nine 3-way, four 4-way, two 5-way, and one 6-way LPEs until February 2024. In 2023 alone, this program facilitated 64 LDLTs, constituting 27.7% of the total 231 LDLTs performed. This paper presents the world's first two 5-way LPEs and the first 6-way LPE.

Characteristics of living liver donors in a national referral hospital in Indonesia: a 13-year experience with living donor liver transplantation

Background

Hepatocellular carcinoma and biliary atresia lead to end-stage liver disease, which requires liver transplantation and is linked to increased mortality. Dr. Cipto Mangunkusumo Hospital is the national referral center in Indonesia and is the only center that routinely performs living donor liver transplantation (LDLT). This study presents the characteristics of living liver donors (LLDs) in Indonesia.

Methods

Using the LDLT registry, we conducted a retrospective analysis of all approved donors from 2010 to 2022. The variables included clinical characteristics of the donors, graft types, and intraoperative and postoperative characteristics.

Results

The LDLT rate has increased from 5.8 to 8.8 procedures/year in the last 8 years. The average age of the 76 LLDs was 31.8 years. They were predominantly female (59%) and lived within a family relationship (90%). Pediatric LDLT was more frequent than adult LDLT (88% vs. 12%, respectively). Most grafts (86%) were obtained by left lateral sectionectomy, with a median ratio of remnant liver volume to total liver volume of 79.5% (range, 47.7%-85.8%) and a mean graft-to-recipient weight ratio of 2.65%±1.21%. The median intensive care unit length of stay (LOS) was 2 days (range, 1-5 days) and the total hospital LOS was 7 days (range, 4-28 days). The complication rate was 23%. No donor mortality was reported.

Conclusions

LDLT in Indonesia has increased over the years. The shortage of donors for adult-to-adult liver transplantation is due to cultural differences and challenges in finding eligible donors. This study aims to explain the eligibility criteria of LLDs and contribute to creating a national policy.

Imaging Evaluation of the Living Liver Donor: A Systems-Based Approach

Liver transplant is the definitive treatment of end-stage liver disease and early hepatocellular carcinoma. The number of liver transplant surgeries done is highly affected by the number and availability of deceased donor organs. Living donor liver transplantation has emerged as an alternative source of donors, increasing the availability of organs for transplant. Many factors must be considered when choosing living donor candidates to maintain a high level of donor safety and organ survival. To that end, potential donors undergo a rigorous pre-donation workup.

Is it Possible to Avoid Liver Biopsy in Living Donors for Liver Transplantation by Using Two-Dimensional Shear Wave Elastography?

PURPOSE

The present study aims to evaluate the correlation of two-dimensional shear wave elastography results with histopathological findings performed simultaneously with liver biopsy (LB) in healthy liver transplant donors.

METHODS

A total of 53 living donors, 35 male and 18 female, were included in this prospective, observational, single-center study. Patients with abnormal liver function tests were not included in our study. Hepatosteatosis, fibrosis, and inflammation were evaluated with the Fatty Liver Inhibition of Progression and Steatosis, Activity, and Fibrosis algorithm of donor LB.

RESULTS

The mean age of the donors was 33.04 ± 9.07 years and the mean body mass index was 23.41 ± 6.23 kg/m². The mean elastography kilo pascal (kPA) value of all donors was determined as 6.03 ± 2.32 kPa. The mean LB activity scores of the donors were found to be 1.64 ± 1.18 and ranged from 0 to 5. There was no significant correlation between elastography kPa value and pathologic activity score, steatosis score, balloon degeneration, and inflammation grade fibrosis scores (P > .05).

CONCLUSION

Shear wave elastography measurements showed that the predictive power of pathologic findings in donor LB was not sufficient.

Practice patterns of the medical evaluation of living liver donors in the United States

Living donor liver transplantation (LDLT) can help address the growing organ shortage in the United States, yet little is known about the current practice patterns in the medical evaluation of living liver donors. We conducted a 131-question survey of all 53 active LDLT transplant programs in the United States to assess current LDLT practices. The response rate was 100%. Donor acceptance rate was 0.33 with an interquartile range of 0.33-0.54 across all centers. Areas of high intercenter agreement included minimum age cutoff of 18 years (73.6%) and the exclusion of those with greater than Class 1 obesity (body mass index, 30.0-34.9 m/kg 2 ) (88.4%). Diabetes mellitus was not an absolute exclusion at most centers (61.5%). Selective liver biopsies were performed for steatosis or iron overload on imaging (67.9% and 62.3%, respectively) or for elevated liver enzymes (60.4%). Steatohepatitis is considered an exclusion at most centers (84.9%). The most common hypercoagulable tests performed were factor V Leiden (FVL) (88.5%), protein C (73.1%), protein S (71.2%), antithrombin III (71.2%) and prothrombin gene mutation (65.4%). At 41.5% of centers, donors were allowed to proceed with donation with FVL heterozygote status. Most programs discontinue oral contraceptive pills at least 28 days prior to surgery. At most centers, the need for cardiovascular ischemic risk testing is based on age (73.6%) and the presence of one or more cardiac risk factors (68.0%). Defining areas of practice consensus and variation underscores the need for data generation to develop evidence-based guidance for the evaluation and risk assessment of living liver donors.

Positive autoantibodies in living liver donors

BACKGROUND

There is a nationwide shortage of organs available for liver transplantation. Living donors help meet this growing demand. Not uncommonly, donors will have positive autoantibodies. However, it is unclear whether donor positive autoantibodies are correlated with worse outcomes following living liver donor transplantations.

AIM

To analyze the significance of positive autoantibodies in donors on post-transplant outcomes in recipients.

METHODS

We performed a retrospective review of living liver donors who had undergone liver transplantation between January 1, 2012 and August 31, 2021. Demographic characteristics and pre-transplant data including antinuclear antibodies (ANA) and anti-smooth muscle antibody titers were collected in donors. Outcomes of interest were post-transplantation complications including mortality, biliary strictures, biliary leaks, infection, and rejection. Pediatric recipients and donors without measured pre-transplant autoantibody serologies were excluded from this study.

RESULTS

172 living donor liver transplantations were performed during the study period, of which 115 patients met inclusion criteria. 37 (32%) living donors were autoantibody-positive with a median ANA titer of 1:160 (range 1:80 to 1:1280) and median anti-SMA titer of 1:40 (range 1:20 to 1:160). There were no significant differences in baseline demographics between the autoantibody positive and negative donors. Post-transplantation rates of death (P value = 1), infections (P value = 0.66), and overall rates of complications (P value = 0.52) were similar between the autoantibody positive and negative groups. Higher incidences of anastomotic strictures and rejection were observed in the autoantibody positive group; however, these differences were not statistically significant (P value = 0.07 and P value = 0.30 respectively).

CONCLUSION

Isolated pre-transplant autoantibody positivity is not correlated to worse post-transplant outcomes in living liver donor transplants.

Survival Benefit of Living-Donor Liver Transplant

Importance

Despite the acceptance of living-donor liver transplant (LDLT) as a lifesaving procedure for end-stage liver disease, it remains underused in the United States. Quantification of lifetime survival benefit and the Model for End-stage Liver Disease incorporating sodium levels (MELD-Na) score range at which benefit outweighs risk in LDLT is necessary to demonstrate its safety and effectiveness.

Objective

To assess the survival benefit, life-years saved, and the MELD-Na score at which that survival benefit was obtained for individuals who received an LDLT compared with that for individuals who remained on the wait list.

Design, Setting, and Participants

This case-control study was a retrospective, secondary analysis of the Scientific Registry of Transplant Recipients database of 119 275 US liver transplant candidates and recipients from January 1, 2012, to September 2, 2021. Liver transplant candidates aged 18 years or older who were assigned to the wait list (N = 116 455) or received LDLT (N = 2820) were included. Patients listed for retransplant or multiorgan transplant and those with prior kidney or liver transplants were excluded.

Exposures

Living-donor liver transplant vs remaining on the wait list.

Main Outcomes and Measures

The primary outcome of this study was life-years saved from receiving an LDLT. Secondary outcomes included 1-year relative mortality and risk, time to equal risk, time to equal survival, and the MELD-Na score at which that survival benefit was obtained for individuals who received an LDLT compared with that for individuals who remained on the wait list. MELD-Na score ranges from 6 to 40 and is well correlated with short-term survival. Higher MELD-Na scores (>20) are associated with an increased risk of death.

Results

The mean (SD) age of the 119 275 study participants was 55.1 (11.2) years, 63% were male, 0.9% were American Indian or Alaska Native, 4.3% were Asian, 8.2% were Black or African American, 15.8% were Hispanic or Latino, 0.2% were Native Hawaiian or Other Pacific Islander, and 70.2% were White. Mortality risk and survival models confirmed a significant survival benefit for patients receiving an LDLT who had a MELD-Na score of 11 or higher (adjusted hazard ratio, 0.64 [95% CI, 0.47-0.88]; P = .006). Living-donor liver transplant recipients gained an additional 13 to 17 life-years compared with patients who never received an LDLT.

Conclusions and Relevance

An LDLT is associated with a substantial survival benefit to patients with end-stage liver disease even at MELD-Na scores as low as 11. The findings of this study suggest that the life-years gained are comparable to or greater than those conferred by any other lifesaving procedure or by a deceased-donor liver transplant. This study's findings challenge current perceptions regarding when LDLT survival benefit occurs.

The use of nondirected donor organs in living donor liver transplantation: Perspectives and guidance

Interest in anonymous nondirected living organ donation is increasing in the United States and a small number of transplantation centers are accumulating an experience regarding nondirected donation in living donor liver transplantation. Herein, we review current transplant policy, discuss emerging data, draw parallels from nondirected kidney donation, and examine relevant considerations in nondirected living liver donation. We aim to provide a consensus guidance to ensure safe evaluation and selection of nondirected living liver donors and a schema for just allocation of nondirected grafts.

Perioperative management of living donor liver transplantation: Part 2 - Donors

Living donor liver transplantation was first developed to mitigate the limited access to deceased donor organs in Asia in the 1990s. This alternative liver transplantation method has become a widely practiced and established transplantation option for adult patients suffering with end-stage liver disease, and it has successfully helped address the shortage of deceased donors. The Society for the Advancement of Transplant Anesthesia and the Korean Society of Transplantation Anesthesiologists jointly reviewed published studies on the perioperative management of adult live liver donors undergoing donor hemi-hepatectomy. The goal of the review is to offer transplant anesthesiologists and critical care physicians a comprehensive overview of the perioperative management of adult live donors. We featured the current status, donor selection process, outcomes and complications, surgical procedure, anesthetic management, Enhanced Recovery After Surgery protocols, avoidance of blood transfusion, and considerations for emergency donation. Recent surgical advances, including laparoscopic donor hemi-hepatectomy and robotic laparoscopic donor surgery, are also addressed.

Healthy Spouses can be Considered as Living Liver Donors

BACKGROUND

Spousal donors have gradually been accepted as an alternative living liver donors to alleviate the organ shortage and prevent donations from children. No information is available regarding the effects of spousal donation on donor safety and recipient outcomes. Our purpose in this study was to determine how spousal liver grafts in living donor liver transplantation (LDLT) affect donor safety and recipient outcomes compared with those of LDLT from children.

METHODS

We retrospectively analyzed 656 patients, including spouses and children, who underwent a right or extended right hepatectomy for living liver donation between January 2009 and December 2018.

RESULTS

Spouses represented 18.8% (n = 123) of living liver donors. Female donors comprised 78.9% (n = 97) of spousal donors, and the proportion of male donors in the children group was 72.6% (n = 387). The mean donor operation time of the spousal group was shorter than that of the children group (330 min vs. 358 min; P = 0.011), and the complication rate in the spousal group was lower than that in the children group (12.2% vs. 22.9%; P = 0.006). However, there were no differences in severe complication rates, hospitalization, or liver function tests between the 2 groups at 3 months after donor surgery. The overall survival of recipients in the spousal group was not reduced compared to that of recipients in the children group.

CONCLUSION

The present study suggests that, with careful selection, spousal donation is feasible and safe in LDLT.

The Landscape of Nondirected Living Liver Donation in the United States

BACKGROUND

Living donor liver transplants (LDLTs) including those from nondirected donors (NDDs) have increased during the past decade, and center-level variations in LDLTs have not yet been described. We sought to quantify changes in the volume of NDD transplants over time and variation in NDD volume between transplant centers. We further examined characteristics of living liver donors and identified factors potentially associated with receiving an NDD liver transplant.

METHODS

Using Scientific Registry of Transplant Recipients data between March 01, 2002, and December 31, 2020, we compared 173 NDDs with 5704 DLDs and 167 NDD recipients with 1153 waitlist candidates.

RESULTS

NDDs increased from 1 (0.4% of LDLTs) in 2002 to 58 (12% of LDLTs) in 2020. Of 150 transplant centers, 35 performed at least 1 NDD transplant. Compared with waitlist candidates, adult NDD recipients were less frequently males (39% versus 62%, P < 0.001), had a lower model for end-stage liver disease (16 versus 18, P = 0.01), and spent fewer days on the waitlist (173 versus 246, P = 0.02). Compared with waitlist candidates, pediatric NDD recipients were younger (50% versus 12% age <2 y, P < 0.001) and more often diagnosed with biliary atresia (66% versus 41%, P < 0.001). Compared with DLDs, NDDs were older (40 versus 35 y, P < 0.001), college educated (83% versus 64%, P < 0.001), White (92% versus 78%, P < 0.001), and more frequently donated left-lateral segment grafts (32.0% versus 14%, P < 0.001).

CONCLUSIONS

Liver NDD transplants continue to expand but remain concentrated at a few centers. Graft distribution favors female adults and pediatric patients with biliary atresia. Racial inequities in adult or pediatric center-level NDD graft distribution were not observed.

Increasing Living Donor Liver Transplantation Using Liver Paired Exchange

BACKGROUND

Living donor liver transplantation (LDLT) continues to be the primary modality of liver transplantation in Asia, but it accounts for about 5% of all liver transplantations in the US. ABO incompatibility is the primary reason motivated donors are declined. Although kidney paired exchanges are common, liver paired exchange (LPE) is still evolving in the US.

STUDY DESIGN

This is a retrospective review (between January 1, 2019, and July 31, 2021) of our initial experience with LPE.

RESULTS

A total of 10 LPEs (20 LDLTs) were performed during the study period. Seven LPEs were initiated by a nondirected O donor. The other 3 pair sets involved 1 ABO compatible and 1 ABO incompatible pair. Transplantations in a pair set were completed within a mean of 4.8 (range 1-14) days of each other. All 20 donors are doing well with no major complications at 12.7 (range 1-20) months. Seventeen of 20 recipients are alive and have good allograft function. One recipient died in the early postoperative period. Two late deaths of patients with functioning allografts were due to COVID-19 (at 8 months) and peritoneal carcinomatosis and gram-negative sepsis (at 9 months).

CONCLUSIONS

LPE is feasible in a high-volume LDLT center and is a useful option to increase LDLT by overcoming ABO incompatibility. Nondirected donors can be utilized to initiate an LPE.

Left lateral segment liver volume is not correlated with anthropometric measures

BACKGROUND

Liver transplantation is definitive therapy for end stage liver disease in pediatric patients. Living donor liver transplantation (LDLT) with the left lateral segment (LLS) is often a feasible option. However, the size of LLS is an important factor in donor suitability - particularly when the recipient weighs less than 10 kg. In the present study, we sought to define a formula for estimating left lateral segment volume (LLSV) in potential LLS donors.

METHODS

We obtained demographic and anthropometric measurements on 50 patients with Computed Tomography (CT) scans to determine whole liver volume (WLV), right liver volume (RLV), and LLSV. We performed univariable and multivariable linear regression with backwards stepwise variable selection (p < 0.10) to determine final models.

RESULTS

Our study found that previously reported anthropometric and demographics variables correlated with volume were significantly associated with WLV and RLV. On univariable analysis, no demographic or anthropometric measures were correlated with LLSV. On multivariable analysis, LLSV was poorly predicted by the final model (R2 = 0.10, Coefficient of Variation [CV] = 42.2) relative to WLV (R2 = 0.33, CV = 18.8) and RLV (R2 = 0.41, CV = 15.8).

CONCLUSION

Potential LLS living donors should not be excluded based on anthropometric data: all potential donors should be evaluated regardless of their size.

Circuitous Path to Live Donor Liver Transplantation from the Coordinator's Perspective

Background: The live donor liver transplantation (LDLT) process is circuitous and requires a considerable amount of coordination and matching in multiple aspects that the literature does not completely address. From the coordinators’ perspective, we systematically analyzed the time and risk factors associated with interruptions in the LDLT process. Methods: In this retrospective single center study, we reviewed the medical records of wait-listed hospitalized patients and potential live donors who arrived for evaluation. We analyzed several characteristics of transplant candidates, including landmark time points of accompanied live donation evaluation processes, time of eventual LDLT, and root causes of not implementing LDLT. Results: From January 2014 to January 2021, 417 patients (342 adults and 75 pediatric patients) were enrolled, of which 331 (79.4%) patients completed the live donor evaluation process, and 205 (49.2%) received LDLT. The median time from being wait-listed to the appearance of a potential live donor was 19.0 (interquartile range 4.0–58.0) days, and the median time from the appearance of the donor to an LDLT or a deceased donor liver transplantation was 68.0 (28.0–188.0) days. The 1-year mortality rate for patients on the waiting list was 34.3%. Presence of hepatitis B virus, encephalopathy, and hypertension as well as increased total bilirubin were risk factors associated with not implementing LDLT, and biliary atresia was a positive predictor. The primary barriers to LDLT were a patient’s critical illness, donor’s physical conditions, motivation for live donation, and stable condition while on the waiting list. Conclusions: Transplant candidates with potential live liver donors do not necessarily receive LDLT. The process requires time, and the most common reason for LDLT failure was critical diseases. Aggressive medical support and tailored management policies for these transplantable patients might help reduce their loss during the process.

Non-alcoholic fatty liver disease and obesity among adult donors are major challenges to living donor liver transplantation: A single-centre experience

OBJECTIVES

Obesity and non-alcoholic fatty liver disease (NAFLD) are rampant in South East Asia. There is paucity of data exploring its' impact on donor suitability for living donor liver transplantation (LDLT). We aimed to describe and examine the factors related to non-utilization of potential donors in our LDLT programme.

METHODS

This is an analysis of prospectively collected data on potential donors for an adult LDLT programme, between January 2017 and December 2019.

RESULTS

Fifty-five donors for 33 potential recipients were evaluated. The mean age was 31.6 ± 8.5 years, 52.7% were female and the ethnic divisions were: Chinese (50.9%), Indian (25.5%) and Malay (23.6%). The mean body mass index (BMI) among potential donors was 25.1 ± 4.0 kg/m²; 25.5% of donors had normal BMI, 23.6% were overweight and 50.9% were obese. Using the CAP modality of Fibroscan®, we identified the following grades of hepatic steatosis: 36.6% S0, 19.5% S1, 2.4% S2 and 41.5% S3. The non-utilization rate of our donors was 74.5% (41/55) and the main reasons were significant hepatic steatosis and/or obesity. Compared to suitable donors, unsuitable donors had significantly greater mean BMI, mean CAP scores, higher rates of dyslipidaemia and NAFLD.

CONCLUSION

NAFLD and obesity represent major challenges to an emerging LDLT programme in Malaysia.

Outcomes of living liver donor candidate evaluations in the Living Donor Collective pilot registry

BACKGROUND

To gather information on long-term outcomes after living donation, the Scientific Registry of Transplant Recipients (SRTR) conducted a pilot on the feasibility of establishing a comprehensive donor candidate registry.

METHODS

A convenience sample of 6 US living liver donor programs evaluated 398 consecutive donor candidates in 2018, ending with the March 12, 2020, COVID-19 emergency.

RESULTS

For 333/398 (83.7%), the donor or program decided whether to donate; 166/333 (49.8%) were approved, and 167/333 (50.2%) were not or opted out. Approval rates varied by program, from 27.0% to 63.3% (median, 46%; intraquartile range, 37.3-51.1%). Of those approved, 90.4% were white, 57.2% were women, 83.1% were < 50 years, and 85.5% had more than a high school education. Of 167 candidates, 131 (78.4%) were not approved or opted out because of: medical risk (10.7%); chronic liver disease risk (11.5%); psychosocial reasons (5.3%); candidate declined (6.1%); anatomical reasons increasing recipient risk (26.0%); recipient-related reasons (33.6%); finances (1.5%); or other (5.3%).

CONCLUSIONS

A comprehensive national registry is feasible and necessary to better understand candidate selection and long-term outcomes. As a result, the US Health Resources and Services Administration asked SRTR to expand the pilot to include all US living donor programs.

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

BACKGROUND

With increasing rates of liver transplantation and a stagnant donor pool, the annual wait list removals have remained high. Living donor liver transplantation (LDLT) is an established modality in expanding the donor pool and is the primary method of liver donation in large parts of the world. Marginal living donors, including those with hepatic steatosis, have been used to expand the donor pool. However, due to negative effects of steatosis on graft and recipient outcomes, current practice excludes overweight or obese donors with more than 10% macro vesicular steatosis. This has limited a potentially important source to help expand the donor pool. Weight loss is known to improve or resolve steatosis and rapid weight loss with short-term interventions have been used to convert marginal donors to low-risk donors in a small series of studies. There is, however, a lack of a consensus driven standardized approach to such interventions.

AIM

To assess the available data on using weight loss interventions in potential living liver donors with steatotic livers and investigated the feasibility, efficacy, and safety of using such donors on the donor, graft and recipient outcomes. The principal objective was to assess if using such treated donor livers, could help expand the donor pool.

METHODS

We performed a comprehensive literature review and meta-analysis on studies examining the role of short-term weight loss interventions in potential living liver donors with hepatic steatosis with the aim of increasing liver donation rates and improving donor, graft, and recipient outcomes.

RESULTS

A total of 6 studies with 102 potential donors were included. Most subjects were males (71). All studies showed a significant reduction in body mass index post-intervention with a mean difference of -2.08 (-3.06, 1.10, I² = 78%). A significant reduction or resolution of hepatic steatosis was seen in 93 of the 102 (91.2%). Comparison of pre- and post-intervention liver biopsies showed a significant reduction in steatosis with a mean difference of -21.22 (-27.02, -15.43, I² = 56%). The liver donation rates post-intervention was 88.5 (74.5, 95.3, I² = 42%). All donors who did not undergo LDLT had either recipient reasons or had fibrosis/steatohepatitis on post intervention biopsies. Post-operative biliary complications in the intervention group were not significantly different compared to controls with an odds ratio of 0.96 [(0.14, 6.69), I² = 0]. The overall post-operative donor, graft, and recipient outcomes in treated donors were not significantly different compared to donors with no steatosis.

CONCLUSION

Use of appropriate short term weight loss interventions in living liver donors is an effective tool in turning marginal donors to low-risk donors and therefore in expanding the donor pool. It is feasible and safe, with comparable donor, graft, and recipient outcomes, to non-obese donors. Larger future prospective studies are needed.

Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) is a viable alternative to liver biopsy for steatosis quantification in living liver donor transplantation

This study aimed to investigate whether magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) can be a viable noninvasive alternative to liver biopsy for the quantification of living liver donor steatosis. Hepatic steatosis for 143 donors was graded by MRI-PDFF. Study endpoints included liver volume regeneration in donors, recipient outcomes including length of hospital stay, deaths, primary non-function (PNF), early allograft dysfunction (EAD), and small for size syndrome (SFSS). Correlation between MRI-PDFF determined donor steatosis and endpoints were analyzed. Donors had lower steatosis grade than non-donors. Donor remnant liver regenerated to an average of 82% of pre-donation volume by 101 ± 24 days with no complications. There was no correlation between percent liver regeneration and steatosis severity. Among recipients, 4 underwent redo-transplantation and 6 died, with no association with degree of steatosis. 52 recipients (36%) fulfilled criteria for EAD (driven by INR), with no difference in hepatic steatosis between groups. MRI-PDFF reliably predicted donor outcomes. Living donors with no or mild steatosis based on MRI-PDFF (ie, <20%) and meeting other criteria for donation can expect favorable post-surgical outcomes, including liver regeneration. Recipients had a low rate of death or retransplantation with no association between mild hepatic steatosis and EAD.

Current status of left lobe adult to adult living donor liver transplantation

PURPOSE OF REVIEW

This review describes the history and current state of left lobe living donor liver transplantation (LDLT). The transplant community continues to face an organ shortage on a global scale, and the expansion of LDLT is attractive because it allows us to provide life-saving liver transplants to individuals without drawing from, or depending on, the limited deceased donor pool. Donor safety is paramount in LDLT, and for this reason, left lobe LDLT is particularly attractive because the donor is left with a larger remnant.

RECENT FINDINGS

This article reviews the donor and recipient evaluations for left lobe LDLT, discusses small for size syndrome and the importance of portal inflow modification, and reviews recipient outcomes in right lobe versus left lobe LDLT.

SUMMARY

Left lobe LDLT was the first adult-to-adult LDLT ever to be performed in Japan in 1993. Since that time, the use of both right and left lobe LDLT has expanded immensely. Recent work in left lobe LDLT has emphasized the need for inflow modification to reduce portal hyperperfusion and early graft dysfunction following transplant. Accumulating evidence suggests, however, that even though early graft dysfunction following LDLT may prolong hospitalization, it does not predict graft or patient survival.

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.

LIVER TRANSPLANTATION: WILL XENOTRANSPLANTATION BE THE ANSWER TO THE DONOR ORGAN SHORTAGE?

Since the first report of a successful liver transplant in 1968, access to this operation has dramatically improved. In 2018, 8,250 patients underwent liver transplantation in the United States. Despite this remarkable advance, a persistent shortage of donor organs remains the primary obstacle to optimal utilization of this life-saving operation. Over the past two decades, transplant professionals have pursued two broad strategies to overcome this roadblock: increasing the number of donor organs and decreasing the number of patients requiring transplantation through advances in medical interventions. Despite these efforts, more than 13,500 patients remained on liver transplant waiting lists at the end of 2018. Almost 1,200 died while waiting, and 1,350 were removed from wait lists because they had become too sick to survive the operation. Clearly, a dramatic new approach to the donor organ shortage is needed. One effort, first attempted by surgeons in the 1960s, was to utilize donor organs from other species (xenotransplantation). The major obstacle to xenotransplantation acceptance has been the fear of transmitting new infectious diseases from animals to humans. As the twentieth century came to a close, national moratoria on xenotransplantation ended both research and clinical activities in this field. The recent discoveries that modern gene-editing techniques can be used to eliminate the retrovirus that is ubiquitous in pigs and that retrovirus-free pigs can be cloned has reopened the possibility that xenotransplantation may be a potentially game-changing approach to eliminating the donor shortage for liver and other solid organ transplant recipients. In response to these advances, the FDA has released comprehensive industry guidelines regarding all aspects of xenotransplantation. This release has resulted in numerous preclinical studies in which organs from genetically modified pigs are transplanted into various nonhuman primates (NHPs). Use of a variety of gene-editing and immunosuppressive techniques has greatly increased the survival of recipient animals in the past few years. Survival of NHP renal transplant recipients has been extended to 435 days, functional cardiac transplant recipients to 195 days, and liver transplant recipients to 29 days. Current research studies using various gene modification strategies combined with newer immunosuppressive protocols are attempting to further extend the survival of these experimental animals. These encouraging results have raised the possibility that clinical xenotransplantation in humans is just beyond the horizon. The most likely candidates for initial clinical studies probably will be kidney transplant recipients who are difficult to crossmatch for human organs, neonates with severe congenital heart disease, and liver transplant candidates with acute liver failure.

Offspring Versus Nonoffspring to Parent Living Donor Liver Transplantation: Does Donor Relationship Matter?

BACKGROUND

Offspring (donor) to parent (recipient) transplant is the most common form of living donor liver transplant in the United States. In kidney transplantation, it has been suggested that female recipients of offspring living donor kidney allografts have inferior outcomes. It is unknown whether such a phenomenon also occurs following living donor liver transplantation.

METHODS

A retrospective analysis was completed of recipients of a living donor liver transplant from January 1998 to January 2018 in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Patients were grouped as having received a living donor liver allograft from either an offspring or a nonoffspring, with exactly 3 HLA matches, as would be expected between an offspring and parent. Graft and patient survival were analyzed using Cox proportional hazards modeling.

RESULTS

A total of 279 offspring to parent and 241 nonoffspring donor liver transplants were included in the analysis. Female recipients of offspring liver allografts had both inferior 10-year graft (52% versus 72%; P < 0.001) and patient survival (52% versus 81%; P < 0.001) compared with female recipients of nonoffspring allografts. No such difference in outcomes was discovered among male recipients. A stratified analysis of sex of offspring donors to female recipients demonstrated that donor male gender was associated with graft failure (HR = 2.87; P = 0.04) and mortality (hazard ratio = 3.89; P = 0.03). Again, this association was not seen with male recipients.

CONCLUSIONS

Among female recipients, offspring to parent living donor liver transplantation yields inferior long-term graft and patient survival. Furthermore, among offspring donors, male sex was strongly associated with inferior outcomes. These findings have significant implications for donor selection.

Considerations of Ultrasound Scanning Approaches in Non-alcoholic Fatty Liver Disease Assessment through Acoustic Structure Quantification

Non-alcoholic fatty liver disease (NAFLD) is a risk factor for hepatic fibrosis and cirrhosis. Acoustic structure quantification (ASQ), based on statistical analysis of ultrasound echoes, is an emerging technique for hepatic steatosis diagnosis. A standardized measurement protocol for ASQ analysis was suggested previously; however, an optimal ultrasound scanning approach has not been concluded thus far. In this study, the suitability of scanning approaches for the ASQ-based evaluation of hepatic steatosis was investigated. Hepatic fat fractions (HFFs; liver segments VIII, III and VI) of 70 living liver donors were assessed with magnetic resonance spectroscopy. A clinical ultrasound machine equipped with a 3-MHz convex transducer was used to scan each participant using the intercostal, epigastric and subcostal planes to acquire raw data for estimating two ASQ parameters (C_m² and focal disturbance [FD] ratio) of segments VIII, III and VI, respectively. The parameters were plotted as functions of the HFF for calculating the values of the correlation coefficient (r) and probability value (p). The diagnostic performance of the parameters in discriminating between the normal and steatotic (≥5 and ≥10%) groups was also compared using receiver operating characteristic (ROC) curves. The C_m² and FD ratio values measured using the epigastric and subcostal planes did not correlate with the severity of hepatic steatosis. However, intercostal imaging exhibited a higher correlation between the ASQ parameters and HFF (r = -0.64, p < 0.001). The diagnostic performance of C_m² and FD ratio in detecting hepatic steatosis using intercostal imaging was also satisfactory (areas under ROC curves >0.8). Intercostal imaging is an appropriate scanning approach for ASQ analysis of the liver.

Living Donor Liver Transplantation: Overview, Imaging Technique, and Diagnostic Considerations

OBJECTIVE. The purpose of this article is to discuss the process of becoming a liver donor, describe the surgical methods used for transplantation, and critically review preoperative and intraoperative imaging techniques. CONCLUSION. Radiologists play a vital role in ensuring the safety of living liver donors; however, consensus guidelines do not exist for imaging protocol or reporting. Standardization would provide more consistent image quality across centers, improve communication with the transplant team, and facilitate data mining for quality assurance and research.

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.

Status of Adult Living Donor Liver Transplantation in the United States: Results from the Adult-To-Adult Living Donor Liver Transplantation Cohort Study

This article reviews the Adult-to-Adult Living Donor Liver Transplant Cohort Study (A2ALL). The findings show that the number of adult-to-adult living donor liver transplants is consistently increasing. Living donor liver transplantation has an important benefit for patients with acute liver failure, does not compromise donor safety, and has lower rates of acute cellular rejection in biologically related donor and recipient. The conclusions from the A2ALL consortium have been critical in transplant advancement, supporting increased use to help decrease waitlist death and improve long-term survival of transplant recipients.

Liver paired exchange: Can the liver emulate the kidney?

Kidney paired exchange (KPE) constitutes 12% of all living donor kidney transplantations (LDKTs) in the United States. The success of KPE programs has prompted many in the liver transplant community to consider the possibility of liver paired exchange (LPE). Though the idea seems promising, the application has been limited to a handful of centers in Asia. In this article, we consider the indications, logistical issues, and ethics for establishing a LPE program in the United States with reference to the principles and advances developed from experience with KPE. Liver Transplantation 24 677-686 2018 AASLD.

Living donor liver transplantation: eliminating the wait for death in end-stage liver disease?

Adult-to-adult living donor liver transplantation (A2ALDLT), outside of Asia, remains an important yet underutilized gift of life. For patients with end-stage liver disease, A2ALDLT is a proven transplantation option, with lower waiting list mortality and suffering, and equivalent or better allograft and patient survival than deceased-donor liver transplantation (DDLT). The risks to living donors and the benefit to their recipients have been carefully defined with long-term level 1 and 2 evidence-based study. An overview of the development and practice of living donor liver transplant (LDLT), including donor and recipient surgical allograft innovation, is provided. The issues of recipient selection, outcomes and morbidity, including disease-variable study and challenges past and present are presented in comparison with DDLT cohorts, and future insights are described. Central to practice is the careful and concise review of donor evaluation and selection and donor outcome, morbidity, quality of life and present and future strategies for donor advocacy and growth of the technique.

Summary of the British Transplantation Society UK Guidelines for Living Donor Liver Transplantation

The British Transplantation Society Guidelines for Living Donor Liver Transplantation was published in July 2015 and is the first national guideline in the field of living donor liver transplantation. The guideline aims to review the evidence relating to the evaluation process of both recipient and donor candidates; address the moral and ethical issues surrounding the procedure; outline the technical aspects of the procedure, including the middle hepatic vein controversy and the "small for size syndrome"; review donor and recipient outcomes and complications including donor mortality; and examine evidence relating to the advantages and disadvantages of living donor liver transplantation. In line with previous guidelines published by the BTS, the guideline has used the Grading of Recommendations Assessment, Development and Evaluation system to rate the strength of evidence and recommendations. This article summarizes the Statements of Recommendation contained in the guideline, which provide a framework for the delivery of living liver donation in the United Kingdom and may be of wide international interest. It is recommended that the full guideline document is consulted for details of the relevant references and evidence base. This may be accessed at http://www.bts.org.uk/BTS/Guidelines_Standards/Current/BTS/Guidelines_Standards/Current_Guidelines.aspx?hkey=e285ca32-5920-4613-ac08-fa9fd90915b5.

Evaluation of donor workups and exclusions in a single-center experience of living donor liver transplantation

The process of evaluating potential donors in liver transplantation is important to ensure donor safety and provide optimal recipient outcomes. However, there has been no report about donor exclusion rates and reasons for such exclusion in Korea. In this study, we aimed to elucidate the outcomes of potential living liver donor evaluation in a major living donor liver transplantation center. From July 2011 to June 2015, prospectively collected data of 726 potential donors for 588 matched recipients were subsequently evaluated. Among 726 potential donors, 374 potential donors (51.5%) finally reached donation; 352 potential donors (48.5%) were excluded for various reasons. Donor reasons were 29.8%, including medical problems, withdrawal of consent, graft volume issues, and identification of a better suitable donor. Recipient reasons were 20.7%, including recipient death or recovery, allocation to deceased donor, and progressions of hepatocellular carcinoma. A total of 38 (5.2%) potential donors had a fatty liver. Among them, 15 (39.5%) potential donors tried short-term weight reduction and eventually were able to donate. In conclusion, the main reasons for donor exclusion were medical problems and withdrawal of consent. Therefore, thorough medical screening and careful examination for donor voluntarism are important in the donor evaluation process. Liver Transplantation 23 614-624 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.

Robust sound speed estimation for ultrasound-based hepatic steatosis assessment

Hepatic steatosis is a common condition, the prevalence of which is increasing along with non-alcoholic fatty liver disease (NAFLD). Currently, the most accurate noninvasive imaging method for diagnosing and quantifying hepatic steatosis is MRI, which estimates the proton-density fat fraction (PDFF) as a measure of fractional fat content. However, MRI suffers several limitations including cost, contra-indications and poor availability. Although conventional ultrasound is widely used by radiologists for hepatic steatosis assessment, it remains qualitative and operator dependent. Interestingly, the speed of sound within soft tissues is known to vary slightly from muscle (1.575 mm · µs^-1) to fat (1.450 mm · µs^-1). Building upon this fact, steatosis could affect liver sound speed when the fat content increases. The main objectives of this study are to propose a robust method for sound speed estimation (SSE) locally in the liver and to assess its accuracy for steatosis detection and staging. This technique was first validated on two phantoms and SSE was assessed with a precision of 0.006 and 0.003 mm · µs^-1 respectively for the two phantoms. Then a preliminary clinical trial (N  =  17 patients) was performed. SSE results was found to be highly correlated with MRI proton density fat fraction (R ²  =  0.69) and biopsy (AUROC  =  0.952) results. This new method based on the assessment of spatio-temporal properties of the local speckle noise for SSE provides an efficient way to diagnose and stage hepatic steatosis.

Spousal hematopoietic stem cell transplantation

We report a pilot series of five patients who received stem cell transplantation (SCT) from a spouse for post-transplant relapse or rejection. The inclusion criterion regarding HLA disparities was three or fewer antigen mismatches in the graft-versus-host direction at the HLA-A, B, and DR loci. Four patients received spousal SCT as a third transplant attempt after post-transplant relapse and one as rescue for graft rejection. The reduced intensity conditioning (RIC) regimen consisted of fludarabine, melphalan, and anti-thymocyte globulin (ATG) with 3 Gy of total body irradiation (TBI) for relapse cases and ATG plus 4 Gy of TBI for the rejection case. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus, methylprednisolone, and mycophenolate mofetil. Peripheral blood stem cells were transplanted. Granulocyte engraftment was achieved in all cases between days 9 and 11 (median, 10) with complete spousal chimerism. In three of the five patients, no acute GVHD was observed, while one case developed grade III GVHD and one case grade IV. All four patients evaluable for the anti-leukemic effect achieved complete remission; however, all relapsed between 106 and 334 day post-transplant, and died between days 152 and 548. We suggest that spousal SCT can be performed as a repetitive SCT using a RIC regimen with low-dose ATG and steroid-containing GVHD prophylaxis.

Two-stage liver transplantation using auxiliary laparoscopically harvested grafts in adults: Emphasizing the concept of "hypersmall graft nursing"

BACKGROUND

Living donor liver transplantation is limited by the donor's risk in case of right liver donation and by the risk of small-for-size syndrome on the recipient in case of left lobe transplantation. This study aimed at evaluating the feasibility and results of two-stage liver transplantation using auxiliary hyper small grafts harvested laparoscopically and discussing relevant technical insights and issues that still need to be overcome.

METHODS

Retrospective analysis involving two patients operated at a tertiary referral center. The recipients underwent left lateral sectionectomy and then auxillary liver transplantation using laparoscopically harvested left lateral section. The native right liver was transiently left in place to sustain the initially small functional graft functional during its hypertrophy.

RESULTS

No donor experienced postoperative complication. After 7days, the hypertrophy rate was 112% (105-120). Doppler assessments during the first two postoperative weeks showed progressive portal vein inflow decrease in the right native livers and portal vein inflow increase in the grafts. Liver biopsies on postoperative day 7 showed no lesion of overperfusion. No recipient experienced liver failure or small-for-size syndrome. Second stage hepatectomy of the native liver was undertaken in one patient. In the other patient, biliary stenosis on postoperative day 30 precluded second stage hepatectomy. This patient required retransplantation after one year.

CONCLUSIONS AND RELEVANCE

The current strategy increases donor safety and may allow increasing the pool of available grafts. Refinements in the management of the native right liver are however required to improve the feasibility rate of this strategy.

Declining liver graft quality threatens the future of liver transplantation in the United States

National liver transplantation (LT) volume has declined since 2006, in part because of worsening donor organ quality. Trends that degrade organ quality are expected to continue over the next 2 decades. We used the United Network for Organ Sharing (UNOS) database to inform a 20-year discrete event simulation estimating LT volume from 2010 to 2030. Data to inform the model were obtained from deceased organ donors between 2000 and 2009. If donor liver utilization practices remain constant, utilization will fall from 78% to 44% by 2030, resulting in 2230 fewer LTs. If transplant centers increase their risk tolerance for marginal grafts, utilization would decrease to 48%. The institution of "opt-out" organ donation policies to increase the donor pool would still result in 1380 to 1866 fewer transplants. Ex vivo perfusion techniques that increase the use of marginal donor livers may stabilize LT volume. Otherwise, the number of LTs in the United States will decrease substantially over the next 15 years. In conclusion, the transplant community will need to accept inferior grafts and potentially worse posttransplant outcomes and/or develop new strategies for increasing organ donation and utilization in order to maintain the number of LTs at the current level.

Recipient factors associated with having a potential living donor for liver transplantation

Because of a persistent discrepancy between the demand for liver transplantation (LT) and the supply of deceased donor organs, there is an interest in increasing living donation rates at centers trained in this method of transplantation. We examined a large socioeconomically heterogeneous cohort of patients listed for LT to identify recipient factors associated with living donation. We retrospectively reviewed 491 consecutive patients who were listed for LT at our center over a 24-month period. Demographic, medical, and socioeconomic data were extracted from electronic records and compared between those who had a potential living donor (LD) volunteer for assessment and those who did not; 245 patients (50%) had at least 1 potential LD volunteer for assessment. Multivariate logistic regression analysis identified that patients with a LD were more likely to have Child-Pugh C disease (odds ratio [OR], 2.44; P = 0.02), and less likely to be older (OR, 0.96; P = 0.002), single (OR, 0.34; P = 0.006), divorced (OR, 0.53; P = 0.03), immigrants (OR, 0.38; P = 0.049), or from the lowest income quintile (OR, 0.44; P = 0.02). In conclusion, this analysis has identified several factors associated with access to living donation. More research is warranted to define and overcome barriers to living donor liver transplantation through targeted interventions in underrepresented populations.

Review of anesthesia in liver transplantation

Liver transplantation (LT) is a well-accepted treatment modality of many end-stage liver diseases. The main issue in LT is the shortage of deceased donors to accommodate the needs of patients waiting for such transplants. Live donors have tremendously increased the pool of available liver grafts, especially in countries where deceased donors are not common. The main ethical concern of this procedure is the safety of healthy donors, who undergo a major abdominal surgery not for their own health, but to help cure others. The first part of the review concentrates on live donor selection, preanesthetic evaluation, and intraoperative anesthetic care for living liver donors. The second part reviews patient evaluation, intraoperative anesthesia monitoring, and fluid management of the recipient. This review provides up-to-date information to help improve the quality of anesthesia, and contribute to the success of LT and increase the long-term survival of the recipients.