An Exceptional Series: 5000 Living Donor Liver Transplantations at Asan Medical Center, Seoul, Korea

Defining Surgical Difficulty During Open Right Lobe Donor Hepatectomy and its Prediction Using Preoperative Donor Computed Tomography Morphometry

Background

There is no accepted way to define difficult donor hepatectomy (DiffDH) during open right live donor hepatectomy (ORLDH). There are also no studies exploring association between DiffDH and early donor outcomes or reliable pre-operative predictors of DiffDH.

Methods

Consecutive ORLDH performed over 18 months at a single center were included. Intraoperative parameters were used to develop an objective definition of DiffDH. The impact of DiffDH on early postoperative outcomes and achievement of textbook outcome (TO) was evaluated. Donor morphometry data on axial and coronal sections of donor computed tomography (CT) at the level of portal bifurcation were collected. Donor and graft factors predictive of DiffDH were evaluated using univariate and multivariate logistic regression.

Results

One-hundred-eleven donors (male: 40.5%, age: 34 ± 9.5 years) underwent ORLDH during the study period. The difficulty score was constructed using five intraoperative parameters, i.e., operating time, transection time, estimated blood loss, need for intraoperative vasopressors, and need for Pringle maneuver. Donors were classified as DiffDH (score ≥ 2) or standard donor hepatectomy (StDH) (score <2). Twenty-nine donors (26%) were classified as DiffDH. DiffDH donors suffered greater all-cause morbidity (P = 0.004) but not major morbidity (Clavien-Dindo score >2; P = 0.651), more perioperative transfusion (P = 0.013), increased postoperative systemic inflammatory response syndrome (P = 0.034), delay in achieving full oral diet (P = 0.047), and a 70% reduced chance of achieving TO as compared to StDH (P = 0.007). On logistic regression analysis, increasing right lobe anteroposterior depth (RLdepth) was identified as an independent predictor of DiffDH (Odds ratio: 2.0 (95% confidence interval = 1.2, 3.3), P < 0.006). Receiver operating characteristic curve analysis identified an RLdepth of >14 cm as the best predictor of DiffDH (sensitivity:79%, specificity: 66%, area under curve = 0.803, P < 0.001).

Conclusion

We report a novel definition of DiffDH and show that it is associated with worse postoperative outcomes, including a lesser chance of achieving TO. We also report that DiffDH can be predicted from readily available donor CT parameters.

Temporal evolution of living donor liver transplantation survival-A United Network for Organ Sharing registry study

Living donor liver transplantation (LDLT) is a curative treatment for various liver diseases, reducing waitlist times and associated mortality. We aimed to assess the overall survival (OS), identify predictors for mortality, and analyze differences in risk factors over time. Adult patients undergoing LDLT were selected from the United Network for Organ Sharing database from inception (1987) to 2023. The Kaplan-Meier method was used for analysis, and multivariable Cox proportional hazard models were conducted. In total, 7257 LDLT recipients with a median age of 54 years (interquartile range [IQR]: 45-61 years), 54% male, 80% non-Hispanic White, body mass index of 26.3 kg/m2 (IQR: 23.2-30.0 kg/m2), and model for end-stage liver disease score of 15 (IQR: 11-19) were included. The median cold ischemic time was 1.6 hours (IQR: 1.0-2.3 hours) with 88% right lobe grafts. The follow-up was 4.0 years (IQR: 1.0-9.2 years). The contemporary reached median OS was 17.0 years (95% CI: 16.1, 18.1 years), with the following OS estimates: 1 year 95%; 3 years 89%; 5 years 84%; 10 years 72%; 15 years 56%; and 20 years 43%. Nine independent factors associated with mortality were identified, with an independent improved OS in the recent time era (adjusted hazards ratio: 0.53; 95% CI: 0.39, 0.71). The median center-caseload per year was 5 (IQR: 2-10), with observed center-specific improvement of OS. LDLT is a safe procedure with excellent OS. Its efficacy has improved despite an increase of risk parameters, suggesting its limits are yet to be met.

Outcomes of 6000 living donor liver transplantation procedures: a pioneering experience at ASAN Medical Center

Living donor liver transplantation (LDLT) has emerged as a favorable alternative to deceased donor liver transplantation, significantly reducing waitlist mortality, particularly in Asian countries with very low deceased organ donation rates. Asan Medical Center (AMC) in South Korea has pioneered innovative LDLT surgical techniques and become established as an extremely high-volume center for LDLT. This retrospective study analyzed 6000 consecutive LDLT procedures, including 510 dual-graft procedures, performed at AMC between December 1994 and January 2021. Of these, 312 LDLT procedures were performed in children aged < 18 years. In adult recipients, liver cirrhosis (LC) related to viral hepatitis was the most common indication, occurring in 69.8% of cases. Biliary atresia (46.8%) was the most common indication for pediatric LDLT. This study demonstrated outstanding long-term outcomes, with patient survival rates at 1, 5, 10, and 20 years of 92.7%, 85.9%, 82.1%, and 70.9%, respectively, in LDLT group for adults aged 50 and under at the time of LDLT, and 92.9%, 89.0%, 88.1%, and 81.9%, respectively, in the pediatric group. The in-hospital mortality rate of adult recipients was 3.8% (n = 214/5688). This study demonstrates the importance of refined surgical techniques, selection of grafts tailored to the recipient, and comprehensive multidisciplinary perioperative patient care in expanding the scope of LDLT and improving recipient outcomes.

Achieving 400 Living Donor Liver Transplantations Annually During the COVID-19 Pandemic: A Single-Center Experience

BACKGROUND

The COVID-19 pandemic has had a major impact on liver transplantation (LT) and living donor programs globally.

PURPOSE

In this study, we aimed to present the principles and strategies of our LT program during the pandemic period and describe its achievements.

BASIC PROCEDURES

We retrospectively reviewed the outcomes of 1417 LTs performed at Asan Medical Center, Seoul, Korea, from 2020 to 2022. Of these, 216 recipients who received transplants from deceased donors were excluded, and 1201 recipients who received transplants from 1268 live donors were included in the study, including 38 children <18 years old.

MAIN FINDINGS

Among the 1201 living donor LT (LDLT) recipients, the most common indication for LT was unresectable hepatocellular carcinoma (315/1163, 27.1%) in adults and biliary atresia (29/38, 76.3%) in pediatric recipients. Emergency LDLT was performed in 40 patients (3.3%). The median model of end-stage liver disease and pediatric end-stage liver disease scores were 13.9 ± 7.2 and 13.8 ± 7.1, respectively. In-hospital mortality of recipients was higher than usual at 2.2%, but the cause of death was not related to COVID-19 infection. Of the 1268 live donors who underwent hepatectomy for liver donation, 660 (52.1%) underwent hepatectomy using a minimally invasive approach. Although 17 (1.3%) live donors experienced major complications, there were no serious life-threatening complications and no mortality.

CONCLUSION

Even in a pandemic era, a team with well-established infection control protocols, patient-tailored surgical strategies, and thorough perioperative care can maintain LDLT at a similar quantitative and qualitative level as in a non-pandemic era.

Application of attenuation imaging for the detection of fatty liver in potential liver donors

PURPOSE

In living donor liver transplantation (LDLT), fatty liver adversely affects the outcome in donors or in recipients. The attenuation imaging (ATI) may be valuable for detecting fatty liver in potential liver donors. We aimed to investigate the role of ATI in screening liver donors.

METHOD

In this prospective study, potential liver donors undergoing MR examination, including proton MR spectroscopy (1H-MRS), were enrolled between January 2020 and December 2021 (study identifier: KCT0004486). All participants underwent ATI examinations to assess fatty liver disease. The reference standard for fatty liver was the hepatic fat fraction (HFF) on 1H-MRS, with 8% defined as the threshold for significant fatty liver. The correlation between attenuation coefficient (AC) and HFF was evaluated using Spearman's correlation coefficient. The diagnostic performance of AC for the detection of fatty liver disease was evaluated using receiver operating characteristic curve analysis.

RESULTS

A total of 102 participants (median age, 37 [range, 20-61] years; 65 men) were enrolled. Nineteen participants (18.6%) had significant fatty liver on 1H-MRS. AC significantly correlated with HFF on 1H-MRS (ρ = 0.674, P < 0.001), and was significantly higher in patients with HFF on 1H-MRS ≥ 8% than in patients with HFF on 1H-MRS < 8% (0.76 vs. 0.59, P < 0.001). By using the cutoff value of 0.66, the area under the curve of AC for the detection of significant fatty liver on 1H-MRS was 0.923 (95% confidence interval [CI]: 0.853-0.967), with sensitivity, specificity, and negative predictive values of 89.5% (95% CI: 66.9-98.7%), 83.1% (95% CI: 73.3-90.5%), and 97.2% (95% CI: 90.3-99.2%), respectively.

CONCLUSIONS

ATI showed good diagnostic performance with a high negative predictive value for the detection of significant fatty liver among potential liver donors.

Surgical Strategies for Recurrent Hepatocellular Carcinoma after Resection: A Review of Current Evidence

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, and both liver resection and liver transplantation are considered potentially curative options. However, high recurrence rates affect the prognosis depending both on the primary HCC pathology characteristics or on the type and time of the relapse. While great attention has been usually posted on treatment algorithms for the first HCC, treatment algorithms for recurrent HCC (rHCC) are lacking. In these cases, surgery still represents a curative option with both redo hepatectomy and/or salvage liver transplantation, which are considered valid treatments in selected patients. In the current era of personalised medicine with promises of new systemic-targeted immuno-chemotherapies, we wished to perform a narrative review of the literature on the role of surgical strategies for rHCC.

Low utilization of adult-to-adult LDLT in Western countries despite excellent outcomes: International multicenter analysis of the US, the UK, and Canada

BACKGROUND & AIMS

Adult-to-adult living donor liver transplantation (LDLT) offers an opportunity to decrease the liver transplant waitlist and reduce waitlist mortality. We sought to compare donor and recipient characteristics and post-transplant outcomes after LDLT in the US, the UK, and Canada.

METHODS

This is a retrospective multicenter cohort-study of adults (≥18-years) who underwent primary LDLT between Jan-2008 and Dec-2018 from three national liver transplantation registries: United Network for Organ Sharing (US), National Health Service Blood and Transplantation (UK), and the Canadian Organ Replacement Registry (Canada). Patients undergoing retransplantation or multi-organ transplantation were excluded. Post-transplant survival was evaluated using the Kaplan-Meier method, and multivariable adjustments were performed using Cox proportional-hazards models with mixed-effect modeling.

RESULTS

A total of 2,954 living donor liver transplants were performed (US: n = 2,328; Canada: n = 529; UK: n = 97). Canada has maintained the highest proportion of LDLT utilization over time (proportion of LDLT in 2008 - US: 3.3%; Canada: 19.5%; UK: 1.7%; p <0.001 - in 2018 - US: 5.0%; Canada: 13.6%; UK: 0.4%; p <0.001). The 1-, 5-, and 10-year patient survival was 92.6%, 82.8%, and 70.0% in the US vs. 96.1%, 89.9%, and 82.2% in Canada vs. 91.4%, 85.4%, and 66.7% in the UK. After adjustment for characteristics of donors, recipients, transplant year, and treating transplant center as a random effect, all countries had a non-statistically significantly different mortality hazard post-LDLT (Ref US: Canada hazard ratio 0.53, 95% CI 0.28-1.01, p = 0.05; UK hazard ratio 1.09, 95% CI 0.59-2.02, p = 0.78).

CONCLUSIONS

The use of LDLT has remained low in the US, the UK and Canada. Despite this, long-term survival is excellent. Continued efforts to increase LDLT utilization in these countries may be warranted due to the growing waitlist and differences in allocation that may disadvantage patients currently awaiting liver transplantation.

LAY SUMMARY

This multicenter international comparative analysis of living donor liver transplantation in the United States, the United Kingdom, and Canada demonstrates that despite low use of the procedure, the long-term outcomes are excellent. In addition, the mortality risk is not statistically significantly different between the evaluated countries. However, the incidence and risk of retransplantation differs between the countries, being the highest in the United Kingdom and lowest in the United States.

Identification of hepatic steatosis in living liver donors by machine learning models

Selecting an optimal donor for living donor liver transplantation is crucial for the safety of both the donor and recipient, and hepatic steatosis is an important consideration. We aimed to build a prediction model with noninvasive variables to evaluate macrovesicular steatosis in potential donors by using various prediction models. The study population comprised potential living donors who had undergone donation workup, including percutaneous liver biopsy, in the Republic of Korea between 2016 and 2019. Meaningful macrovesicular hepatic steatosis was defined as >5%. Whole data were divided into training (70.5%) and test (29.5%) data sets based on the date of liver biopsy. Random forest, support vector machine, regularized discriminant analysis, mixture discriminant analysis, flexible discriminant analysis, and deep neural network machine learning methods as well as traditional logistic regression were employed. The mean patient age was 31.4 years, and 66.3% of the patients were men. Of the 1652 patients, 518 (31.4%) had >5% macrovesicular steatosis on the liver biopsy specimen. The logistic model had the best prediction power and prediction performances with an accuracy of 80.0% and 80.9% in the training and test data sets, respectively. A cut-off value of 31.1% for the predicted risk of hepatic steatosis was selected with a sensitivity of 77.7% and specificity of 81.0%. We have provided our model on the website (https://hanseungbong.shinyapps.io/shiny_app_up/) under the name DONATION Model. Our algorithm to predict macrovesicular steatosis using routine parameters is beneficial for identifying optimal potential living donors by avoiding superfluous liver biopsy results.

Twenty-year longitudinal follow-up after liver transplantation: a single-center experience with 251 consecutive patients

Background

The outcomes of liver transplantation (LT) have improved, but actual 20-year survival data have rarely been presented.

Methods

Longitudinal follow-up data of 20-year LT survivors were retrospectively analyzed. The LT database of our institution was searched to identify patients who underwent primary LT from January 2000 to December 2001. The study cohort of 251 patients was divided into three groups 207 adults who underwent living donor LT (LDLT), 22 adults who underwent deceased donor LT (DDLT), and 22 pediatric patients who underwent LT.

Results

Hepatitis B virus-associated liver cirrhosis and biliary atresia were the most common indications for adult and pediatric LT, respectively. Seven patients required retransplantation, including six who underwent DDLT and one who underwent LDLT. Twenty-two patients died within 3 months after LT and 69 died at later intervals. The overall survival rates at 1, 3, 5, 10, and 20 years were 86.4%, 79.6%, 77.7%, 72.8%, and 62.6%, respectively, in the adult LDLT group; 86.4%, 72.7%, 72.7%, 72.7%, and 68.2%, respectively, in the adult DDLT group; and 86.4%, 86.4%, 81.8%, 81.8%, and 77.3%, respectively, in the pediatric LT group (P=0.545). Common immunosuppressive regimens at 20 years included tacrolimus monotherapy, tacrolimus-mycophenolate dual therapy, cyclosporine monotherapy, and mycophenolate monotherapy.

Conclusions

The present study is the first report of actual 20-year survival data from a Korean high-volume LT center. The graft and patient survival outcomes reflected the early experiences of LT in our institution, with long-term outcomes being similar regardless of graft type and patient age.

Robotic donor hepatectomy: A major breakthrough in living donor liver transplantation

Living donation in many countries is the main resource of organs. Healthy, volunteering individuals deserve the highest safety standards possible in addition to the least invasive technique to procure the organs. Since the introduction of living donor liver transplantation, many efforts have been made to minimize the surgical trauma inherent to living donor surgery. The journey started with a large Mercedes incision and evolved to reverse L-shaped and small upper midline incisions before the introduction of minimally invasive laparoscopic techniques originated. The technical difficulties of the laparoscopic approach due to suboptimal instrumentation, challenging ergonomics, and the long learning curve limited the application of the fully laparoscopic approach to a few centers. The recent introduction of the robotic platform with its superb optical system and advanced instruments allows for the first time, a genuine emulation of open donor surgery in a closed abdomen, thus allowing all liver donors to benefit from minimally invasive surgery (better cosmesis, less pain and morbidity, and better quality of life) without compromising donor safety. This attribute in combination with the ubiquitous presence of the robot in major transplant centers may well lead to the desired endpoint of this technology, namely, the widespread dissemination of minimally invasive donor surgery.

Recipient liver splitting to facilitate piggyback hepatectomy in adult living donor liver transplantation

Recipient hepatectomy for an enlarged stony-hard liver is a demanding procedure, thus it is often accompanied by massive blood loss. Recipient liver splitting under prolonged hepatic inflow occlusion would facilitate the piggyback recipient hepatectomy. We herein present a case of recipient liver splitting, which was used for living donor liver transplantation (LDLT). A 48-year-old male patient diagnosed with acute-on-chronic liver failure underwent LDLT. During the recipient operation, the native liver was stony-hard and heavily adherent to the retrohepatic inferior vena cava (IVC). During liver mobilization, diffuse oozing occurred due to disseminated intravascular coagulation. As a change in the concept, we decided to perform in situ liver splitting of the recipient liver to facilitate dissection of the retrohepatic IVC. Under hepatic inflow occlusion, right-left liver splitting was performed along the usual plane of extended left hepatectomy. The procedures time for recipient liver splitting and removal was 60 minutes. A modified right liver graft recovered from his daughter was implanted according to the standard procedures of LDLT. We think that recipient liver splitting is a feasible technical option for coping with difficult recipient hepatectomy, especially in patients with an enlarged stony-hard liver and heavy adhesion around the IVC.

Clinical impact of mild to moderate pulmonary hypertension in living-donor liver transplantation

Severe pulmonary hypertension (PHT) is a contraindication to liver transplantation (LT); however, the prognostic implication of mild to moderate PHT in living-donor LT (LDLT) is unknown. The study cohort retrospectively included 1307 patients with liver cirrhosis who underwent LDLT. PHT was defined as a mean pulmonary artery pressure (PAP) of ≥25 mmHg, measured intraoperatively just before surgery. The primary endpoint was graft failure within 1 year after LDLT, including retransplantation or death from any cause. The secondary endpoints were in-hospital adverse events. In the overall cohort, the median Model for End-stage Liver Disease-Sodium (MELD-Na) score was 19, and 100 patients (7.7%) showed PHT. During 1-year follow-up, graft failure occurred in 94 patients (7.2%). Patients with PHT had lower 1-year graft survival (86% vs. 93.4%, P = 0.005) and survival rates (87% vs. 93.6%, P = 0.011). Mean PAP was associated with a high risk of in-hospital adverse events and 1-year graft failure. Adding the mean PAP to the clinical risk model improved the risk prediction. In conclusion, mild to moderate PHT was associated with higher risks of 1-year graft failure and in-hospital events, including mortality after LDLT in patients with liver cirrhosis. Intraoperative mean PAP can help predict the early clinical outcomes after LDLT.

Salvage living donor liver transplantation for hepatocellular carcinoma recurrence after hepatectomy: Quantitative prediction using ADV score

BACKGROUND

Salvage liver transplantation is a definite treatment for recurrent hepatocellular carcinoma (HCC) after hepatectomy. ADV score is calculated by multiplying α-fetoprotein and des-γ-carboxyprothrombin concentrations and tumor volume. Prognostic accuracy of ADV score was assessed in patients undergoing salvage living donor liver transplantation (LDLT) and their outcomes were compared with patients undergoing primary LDLT.

METHODS

This study was a retrospective, single-center, case-controlled study. Outcomes were compared in 125 patients undergoing salvage LDLT from 2007 to 2018 and in 500 propensity score-matched patients undergoing primary LDLT.

RESULTS

In patients undergoing salvage LDLT, median intervals between hepatectomy and tumor recurrence, between first HCC diagnosis and salvage LDLT, and between hepatectomy and salvage LDLT were 12.0, 37.2, and 29.3 months, respectively. Disease-free survival (DFS, P = .98) and overall survival (OS, P = .44) rates did not differ significantly in patients undergoing salvage and primary LDLT. Pretransplant and explant ADV scores were significantly predictive of DFS and OS in patients undergoing salvage and primary LDLT (P < .001). DFS after prior hepatectomy (P = .52) and interval between hepatectomy and LDLT (P = .82) did not affect DFS after salvage LDLT. Milan criteria and ADV score were independently prognostic of DFS and OS following salvage LDLT, and prognosis of patients within and beyond Milan criteria could be further stratified by ADV score.

CONCLUSIONS

Risk factors and posttransplant outcomes were similar in patients undergoing salvage and primary LDLT. ADV score is surrogate biomarker for posttransplant prognosis in salvage and primary LDLT recipients. Prognostic model incorporating ADV scores can help determine whether to perform salvage LDLT.