Left lobe living donor liver transplantation in adults: What is the safety limit?

Trends of liver transplantation in Asia

Liver transplantation (LT) in Asia started comparatively early in 1964, just 1 year after Starzl's trail-blazing first attempt. Despite the quick start, LT was slow to develop in this region. Limited access to universal healthcare, lack of public understanding and support as well as the absence of strong legislation, on a backdrop of a wide range of diverse social, religious, economic and cultural background are all contributory factors. Through strong administrative efforts, the number of DDLTs in selected Asian countries has been slowly rising in recent years. However, Asians are generally still less likely to donate organs than Caucasians after death. The strong demand for LT with limited access to deceased organs has, therefore, led to constant need for innovation in LT this region, with the pioneering of various LDLT techniques and safe expansion of donor pool being driven primarily by Asian centers. Familiarity and the development of technical expertise in donor surgery have also resulted in Asian centers repeatedly pushing the boundaries on minimally invasive donor and recipient surgery. In this article, we focus on the past and present states of LT in Asia and explore the future trends of LT in this region.

Is preoperative weight reduction of living-donor liver transplant recipients and donors harmful to postoperative outcomes?

PURPOSE

Although the incidence of recipients and donors with overweight and obesity is increasing worldwide, few reports have focused on outcomes of preoperative weight reduction (WR) in living-donor liver transplantation (LDLT). Therefore, we examined the outcomes and the impact of WR on the postoperative course.

METHODS

We analyzed 217 consecutive LDLT procedures performed from 2017 to 2022. We divided the recipients and donors into a WR group and non-WR group.

RESULTS

Twenty-two recipients (10.1%) achieved WR (preoperative recipient WR [RWR] group), reducing their weight by 6.8% ± 6.0% within 2.2 ± 1.4 months with a significant decrease in body mass index (BMI) (P < .0001). The RWR group showed no significant differences in short-term postoperative outcomes (operative factors, postoperative liver function tests, amount of ascites, and morbidity) or in the graft survival rate as a long-term outcome (P = .24) compared with the non-RWR group. Forty-one donors (18.9%) achieved WR (preoperative donor WR [DWR] group), reducing their weight by 9.7% ± 6.3% within 3.2 ± 5.8 months with a significant decrease in BMI (P < .0001). Compared with the non-DWR group, the DWR group showed no significant differences in short-term postoperative outcomes between themselves and recipients or in the graft survival rate (P = .49). Furthermore, WR resulted in an increase to 32 donor-eligible and 6 recipient-eligible patients.

CONCLUSION

WR in LDLT recipients and donors had no harmful effect on postoperative outcomes and should lead to increase recipients' chance of undergoing LDLT and to expand the donor pool.

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

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

Feasible living donor liver transplantation for patients on chronic hemodialysis: a multicenter study in East Asian countries

PURPOSES

End-stage liver and kidney disease is an indication for simultaneous liver and kidney transplantation. However, in countries where deceased donor transplantation is not well established, living donor liver transplantation (LDLT) is a realistic option for patients on hemodialysis (HD). We investigated the outcomes of LDLT for patients on HD.

METHODS

We conducted a retrospective multicenter survey of patients on chronic HD who underwent LDLT in East Asian countries. The characteristics of donors and recipients and the short and long-term outcomes were analyzed.

RESULTS

Between 2001 and 2021, 45 patients on HD underwent LDLT and 11 of these patients also underwent kidney transplantation (KT). The overall survival rate at 5 years of the 34 patients who underwent only LDLT was 44.5%. Multivariate analysis identified a low graft recipient weight ratio (< 1%) (p = 0.048) and long HD duration (≥ 10 years) (p = 0.046) as independent predictors of poor overall survival. The major complication was posttransplant bleeding, which occurred in12 patients (35%).

CONCLUSION

It is important to establish the indications for LDLT, taking into consideration graft size and HD duration in candidate patients on HD.

Living Donor Liver Transplantation: Left Lobe or Right Lobe

Living Donor Liver Transplantation (LDLT) has seen great advancements since its inception in 1988. Herein, the nuances of LDLT are discussed spanning from donor evaluation to the recipient operation. Special attention is given to donor anatomy and graft optimization techniques in the recipient.

Increasing practice and acceptable outcomes of high-MELD living donor liver transplantation in the USA

Recent deceased-donor allocation changes in the United States may have increased high-Model for End-Stage Liver Disease (MELD) living donor liver transplantation (LDLT); however, outcomes in these patients remain poorly defined. We aimed to examine the impact of the MELD score on LDLT outcomes. Using UNOS data (January 1, 2010-December 31, 2021), LDLT recipients were identified and stratified into low-MELD (<15), intermediate-MELD (15-24), and high-MELD (≥25) groups. We compared outcomes between MELD-stratified LDLT groups and between MELD-stratified LDLT and donation after brain death liver transplantation recipients. We used Kaplan-Meier analysis to compare graft survival rates and multivariable Cox proportional hazards modeling to identify factors associated with graft outcomes. Of 3558 LDLTs, 1605 (45.1%) were low-MELD, 1616 (45.4%) intermediate-MELD, and 337 (9.5%) high-MELD. Over the study period, the annual number of LDLTs increased from 282 to 569, and the proportion of high-MELD LDLTs increased from 3.9% to 7.7%. Graft survival was significantly higher in low-MELD versus high-MELD LDLT recipients (adjusted HR = 1.36, 95% CI: 1.03-1.79); however, 5-year survival exceeded 70.0% in both groups. We observed no significant difference in graft survival between high-MELD LDLT and high-MELD donation after brain death liver transplantation recipients (adjusted HR: 1.25, 95% CI:0.99-1.58), with a 5-year survival of 71.5% and 77.3%, respectively. Low LDLT center volume (<3 LDLTs/year) and recipient life support requirement were both associated with inferior graft outcomes among high-MELD LDLT recipients. While higher MELD scores confer graft failure risk in LDLT, high-MELD LDLT outcomes are acceptable with similar outcomes to MELD-stratified donation after brain death liver transplantation recipients. Future practice guidance should consider the expansion of LDLT recommendations to high-MELD recipients in centers with expertise to help reduce donor shortage.

An Analysis of 10,000 Cases of Living Donor Liver Transplantation in Japan: Special Reference to the Graft-Versus-Recipient Weight Ratio and Donor Age

OBJECTIVE

To analyze 10,000 cases of living donor liver transplantation (LDLT) recipient data to elucidate outcomes with special reference to the graft-versus-recipient weight ratio (GRWR), based on the Japanese Liver Transplantation Society (JLTS) registry.

BACKGROUND

The JLTS registry has been accurate and complete in characterizing and following trends in patient characteristics and survival of all patients with LDLT.

METHODS

Between November 1989 and August 2021, 10,000 patients underwent LDLT in Japan. The procedures performed during the study period included pediatric liver transplantation (age <18 years, n = 3572) and adult liver transplantation (age ≥18 years, n=6428). Factors related to patient survival (PS) and graft survival (GS) were also analyzed.

RESULTS

The GRWR was <0.7, 0.7 to <0.8, 0.8 to <3, 3 to <5, and ≥5 in 0.2%, 2.0%, 61.8%, 31.8%, and 2.6% of pediatric patients and <0.6, 0.6 to <0.7, 0.7 to <0.8, and ≥0.8 in 8.0%, 12.7%, 17.7%, and 61.5% of adult patients, respectively. Among pediatric recipients, the PS rate up to 5 years was significantly better in cases with a GRWR ≤5 than in those with a GRWR >5. When the GRWR and donor age were combined, among adult recipients 50 to 60 years old, the early PS and GS up to 5 years were significantly better in cases with a GRWR ≥0.7, than in those with a GRWR <0.7. (P = 0.02). In adults, a multivariate analysis showed that GRWR <0.6, transplant era (<2011), donor age (>60 years), recipient age (>60 years), model for end-stage liver disease score (≥20), and center volume (<10) were significant prognostic factors for long-term PS.

CONCLUSION

Although a satisfactory long-term PS and GS, especially in the recent era (2011-2021), was achieved in the JLTS series, a GRWR ≥5 in pediatric cases and relatively old donors with a GRWR <0.7 in adult cases should be managed with caution.

Post Living Donor Liver Transplantation Small-for-size Syndrome: Definitions, Timelines, Biochemical, and Clinical Factors for Diagnosis: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

BACKGROUND

When a partial liver graft is unable to meet the demands of the recipient, a clinical phenomenon, small-for-size syndrome (SFSS), may ensue. Clear definition, diagnosis, and management are needed to optimize transplant outcomes.

METHODS

A Consensus Scientific committee (106 members from 21 countries) performed an extensive literature review on specific aspects of SFSS, recommendations underwent blinded review by an independent panel, and discussion/voting on the recommendations occurred at the Consensus Conference.

RESULTS

The ideal graft-to-recipient weight ratio of ≥0.8% (or graft volume standard liver volume ratio of ≥40%) is recommended. It is also recommended to measure portal pressure or portal blood flow during living donor liver transplantation and maintain a postreperfusion portal pressure of <15 mm Hg and/or portal blood flow of <250 mL/min/100 g graft weight to optimize outcomes. The typical time point to diagnose SFSS is the postoperative day 7 to facilitate treatment and intervention. An objective 3-grade stratification of severity for protocolized management of SFSS is proposed.

CONCLUSIONS

The proposed grading system based on clinical and biochemical factors will help clinicians in the early identification of patients at risk of developing SFSS and institute timely therapeutic measures. The validity of this newly created grading system should be evaluated in future prospective studies.

Preventing Small-for-size Syndrome in Living Donor Liver Transplantation: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) is a well-recognized complication following liver transplantation (LT), with up to 20% developing this following living donor LT (LDLT). Preventing SFSS involves consideration of factors before the surgical procedure, including donor and recipient selection, and factors during the surgical procedure, including adequate outflow reconstruction, graft portal inflow modulation, and management of portosystemic shunts. International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplant Society of India Consensus Conference was convened in January 2023 to develop recommendations for the prediction and management of SFSS in LDLT. The format of the conference was based on the Grading of Recommendations, Assessment, Development, and Evaluation system. International experts in this field were allocated to 4 working groups (diagnosis, prevention, anesthesia, and critical care considerations, and management of established SFSS). The working groups prepared evidence-based recommendations to answer-specific questions considering the currently available literature. The working group members, independent panel, and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and evidence-based recommendations provided by working group 2 that can be implemented to prevent SFSS in LDLT patients.

Management of Established Small-for-size Syndrome in Post Living Donor Liver Transplantation: Medical, Radiological, and Surgical Interventions: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) following living donor liver transplantation is a complication that can lead to devastating outcomes such as prolonged poor graft function and possibly graft loss. Because of the concern about the syndrome, some transplants of mismatched grafts may not be performed. Portal hyperperfusion of a small graft and hyperdynamic splanchnic circulation are recognized as main pathogenic factors for the syndrome. Management of established SFSS is guided by the severity of the presentation with the initial focus on pharmacological therapy to modulate portal flow and provide supportive care to the patient with the goal of facilitating graft regeneration and recovery. When medical management fails or condition progresses with impending dysfunction or even liver failure, interventional radiology (IR) and/or surgical interventions to reduce portal overperfusion should be considered. Although most patients have good outcomes with medical, IR, and/or surgical management that allow graft regeneration, the risk of graft loss increases dramatically in the setting of bilirubin >10 mg/dL and INR>1.6 on postoperative day 7 or isolated bilirubin >20 mg/dL on postoperative day 14. Retransplantation should be considered based on the overall clinical situation and the above postoperative laboratory parameters. The following recommendations focus on medical and IR/surgical management of SFSS as well as considerations and timing of retransplantation when other therapies fail.

Left Lobe First With Purely Laparoscopic Approach: A Novel Strategy to Maximize Donor Safety in Adult Living Donor Liver Transplantation

OBJECTIVE

Evaluate outcome of left-lobe graft (LLG) first combined with purely laparoscopic donor hemihepatectomy (PLDH) as a strategy to minimize donor risk.

BACKGROUND

An LLG first approach and a PLDH are 2 methods used to reduce surgical stress for donors in adult living donor liver transplantation (LDLT). But the risk associated with application LLG first combined with PLDH is not known.

METHODS

From 2012 to 2023, 186 adult LDLTs were performed with hemiliver grafts, procured by open surgery in 95 and PLDH in 91 cases. LLGs were considered first when graft-to-recipient weight ratio ≥0.6%. Following a 4-month adoption process, all donor hepatectomies, since December 2019, were performed laparoscopically.

RESULTS

There was one intraoperative conversion to open (1%). Mean operative times were similar in laparoscopic and open cases (366 vs 371 minutes). PLDH provided shorter hospital stays, lower blood loss, and lower peak aspartate aminotransferase. Peak bilirubin was lower in LLG donors compared with right-lobe graft donors (1.4 vs 2.4 mg/dL, P < 0.01), and PLDH further improved the bilirubin levels in LLG donors (1.2 vs 1.6 mg/dL, P < 0.01). PLDH also afforded a low rate of early complications (Clavien-Dindo grade ≥ II, 8% vs 22%, P = 0.007) and late complications, including incisional hernia (0% vs 13.7%, P < 0.001), compared with open cases. LLG was more likely to have a single duct than a right-lobe graft (89% vs 60%, P < 0.01). Importantly, with the aggressive use of LLG in 47% of adult LDLT, favorable graft survival was achieved without any differences between the type of graft and surgical approach.

CONCLUSIONS

The LLG first with PLDH approach minimizes surgical stress for donors in adult LDLT without compromising recipient outcomes. This strategy can lighten the burden for living donors, which could help expand the donor pool.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

HPi: A Novel Parameter to Predict Graft-related Outcome in Adult Living Donor Liver Transplant

BACKGROUND

Portal hyperperfusion is frequently associated with early allograft dysfunction (EAD). It is imperative to identify patients who would require portal inflow modulation. We aimed to identify factors associated with hyperperfusion-related graft injury and develop a predictive index for the same.

METHODS

Prospectively maintained database was queried to identify 135 adult living donor liver transplant recipients between September 2016 and July 2020. According to the calculated sample size, 96 patients were randomly selected for "test cohort". The remaining 39 patients made the "validation cohort." EAD was defined according to the A2ALL study. "Hyperperfusion index (HPi)," defined as posttransplant portal pressure gradient (ΔPpost)/graft-to-recipient splenic volume ratio (GRSVR), was devised on the basis of laws of flow dynamics and regression analysis.

RESULTS

Overall, 40 patients (29.6%) had EAD, six 90-d mortalities (4.4%) were attributable to EAD. In the test cohort, EAD patients (n = 29, 30.2%) had lower GRSVR (1.00 versus 2.22, P < 0.001), higher ΔPpost (14.8 versus 11.9, P = 0.004), and HPi (20.89 versus 8.67, P < 0.001). Multivariate analysis revealed GRSVR, ΔPpost, and HPi as significant factors to predict EAD. Receiver operating characteristic determined cutoff of HPi ≥9.97 could predict EAD with sensitivity of 90% and specificity of 73% (F-score = 0.712). HPi ≥16.25 predicted 90-d mortality with sensitivity of 100% and specificity of 78.9%. Patients with higher HPi had delayed graft-related recovery. Non-EAD patients had a higher 1-y (96% versus 79%) and 2-y (88% versus 79%) survival. The cutoff of HPi was validated well in the validation cohort (F-score = 0.645) (Hosmer-Lemeshow test, P = 0.89).

CONCLUSIONS

While predicted GRSVR may help identify at-risk patients preoperatively, intraoperatively calculated HPi is more accurate in identifying patients who would require portal inflow modulation. Achieving an HPi below target cutoff significantly decreases the risk of EAD even in low-GRSVR patients.

Is 0.6% Reasonable as the Minimum Requirement of the Graft-to-recipient Weight Ratio Regardless of Lobe Selection in Adult Living-donor Liver Transplantation?

BACKGROUND

Several studies reported favorable outcomes of small-for-size grafts with graft-to-recipient weight ratio (GRWR) <0.8% in living-donor liver transplantation (LDLT). However, their indications should be carefully determined because they must have been indicated for low-risk cases over larger grafts with 0.8% ≤ GRWR. Furthermore, evidence for minimum requirements of GRWR remains inconclusive. We investigated the safety of small-for-size grafts against larger grafts by adjusting for confounding risk factors, and minimum requirement of graft volume in adult LDLT.

METHODS

We enrolled 417 cases of primary adult-to-adult LDLT in our center between 2006 and 2019. The outcomes of small grafts (0.6% ≤ GRWR < 0.8%, n = 113) and large grafts (0.8% ≤ GRWR, n = 289) were mainly compared using a multivariate analysis and Kaplan-Meier estimates.

RESULTS

The multivariate analysis showed that small grafts were not a significant risk factor for overall graft survival (GS). In the Kaplan-Meier analysis, small grafts did not significantly affect overall GS regardless of lobe selection (versus large grafts). However, GRWR < 0.6% was associated with poor overall GS. Although there were no significant differences between the 2 groups, unadjusted Kaplan-Meier curves of small grafts were inferior to those of large grafts in subcohorts with ABO incompatibility, and donor age ≥50 years.

CONCLUSIONS

Similar outcomes were observed for small and large graft use regardless of lobe selection. 0.6% in GRWR was reasonable as the minimum requirement of graft volume in LDLT. However, small grafts should be indicated carefully for high-risk cases.

Ex vivo liver resection followed by autotransplantation in radical resection of gastric cancer liver metastases: A case report

BACKGROUND

Radical resection of gastric cancer liver metastases (GCLM) can increase the 5-year survival rate of GCLM patients. However, patients may lose the theoretical feasibility of surgery due to the critical location of liver metastasis in some cases.

CASE SUMMARY

A 29-year-old woman had a chief complaint of chronic abdominal pain for 1 year. Abdominal computed tomography and magnetic resonance imaging examinations suggested a mass of unknown pathological nature located between the first and second hila and the margin of the lower segment of the right lobe of the liver. The anterior wall of the gastric antrum was unevenly thickened. The diagnosis of (gastric antrum) intramucosal well-differentiated adenocarcinoma was histopathologically confirmed by puncture biopsy with gastroscopy guidance. She underwent radical resection (excision of both gastric tumors and ex vivo liver resection followed by autotransplantation simultaneously) followed by XELOX adjuvant chemotherapy. Without serious postoperative complications, the patient was successfully discharged on the 20^th day after the operation. Pathological examination of the excised specimen indicated that gastrectomy with D2 lymph node dissection for primary gastric tumors and R0 resection for liver metastases were achieved. The resected mass was confirmed to be poorly differentiated gastric carcinoma (hepatoid adenocarcinoma with neuroendocrine differentiation) with liver metastases in segments VIII. No recurrence or metastasis within the liver was found during a 7.5-year follow-up review that began 1 mo after surgery.

CONCLUSION

Application of ex vivo liver resection followed by autotransplantation in radical resection for GCLM can help selected patients with intrahepatic metastases located in complex sites obtain a favorable clinical outcome.

Donor-Recipient Height Mismatch Is Associated With Decreased Survival in Pediatric-to-Adult Liver Transplant Recipients

Liver grafts from pediatric donors represent a small fraction of grafts transplanted into adult recipients, and their use in adults requires special consideration of donor size to prevent perioperative complications. In the past, graft weight or volume ratios have been adopted from the living donor liver transplant literature to guide clinicians; however, these metrics are not regularly available to surgeons accepting deceased donor organs. In this study, we evaluated all pediatric-to-adult liver transplants in the United Network for Organ Sharing Standard Transplant Analysis and Research database from 1987 to 2019, stratified by donor age and donor-recipient height mismatch ratio (HMR; defined as donor height/recipient height). On multivariable regression controlling for cold ischemia time, age, and transplantation era, the use of donors from ages 0 to 4 and 5 to 9 had increased risk of graft failure (hazard ratio [HR], 1.81 [P < 0.01] and HR, 1.16 [P < 0.01], respectively) compared with donors aged 15 to 17. On Kaplan-Meier survival analysis, a HMR < 0.8 was associated with inferior graft survival (mean, 11.8 versus 14.6 years; log-rank P < 0.001) and inferior patient survival (mean, 13.5 versus 14.9 years; log-rank P < 0.01) when compared with pairs with similar height (HMR, 0.95-1.05; ie, donors within 5% of recipient height). This study demonstrates that both young donor age and low HMR confer additional risk in adult recipients of pediatric liver grafts.

Heterotopic segmental liver transplantation on splenic vessels after splenectomy with delayed native hepatectomy after graft regeneration: A new technique to enhance liver transplantation

We describe a patient with liver metastases from colorectal cancer treated with chemotherapy and hepatic resection, who developed unresectable multifocal liver recurrence and who received liver transplantation using a novel planned technique: heterotopic transplantation of segment 2-3 in the splenic fossa with splenectomy and delayed hepatectomy after regeneration of the transplanted graft. We transplanted a segmental liver graft after in-situ splitting without any impact on the waiting list, as it was previously rejected for pediatric and adult transplantation. The volume of the graft was insufficient to provide liver function to the recipient, so we performed this novel operation. The graft was anastomosed to the splenic vessels after splenectomy, and the native liver portal flow was modulated to enhance graft regeneration, leaving the native recipient liver intact. The volume of the graft doubled during the next 2 weeks and the native liver was removed. After 8 months, the patient lives with a functioning liver in the splenic fossa and without abdominal tumor recurrence. This is the first case reported of a segmental graft transplanted replacing the spleen and modulating the portal flow to favor graft growth, with delayed native hepatectomy.

Small-for-size graft, small-for-size syndrome and inflow modulation in living donor liver transplantation

The extended application of living donor liver transplantation (LDLT) has revealed the problem of graft size mismatching called "small-for-size syndrome (SFSS)." The initial trials to resolve this problem involved increasing the procured graft size, from left to right, and even extending to include a right lobe graft. Clinical cases of living right lobe donations have been reported since then, drawing attention to the risks of increasing the liver volume procured from a living donor. However, not only other modes of increasing graft volume (GV) such as auxiliary or dual liver transplantation, but also control of the increased portal pressure caused by a small-for-size graft (SFSG), such as a porto-systemic shunt or splenectomy and optimal outflow reconstruction, have been trialed with some positive results. To establish an effective strategy for transplanting SFSG and preventing SFSS, it is essential to have precise knowledge and tactics to evaluate graft quality and GV, when performing these LDLTs with portal pressure control and good venous outflow. Thus, we reviewed the updated literature on the pathogenesis of and strategies for using SFSG.

Small-for-size syndrome in liver transplantation: Definition, pathophysiology and management

BACKGROUND

Since the first success in an adult patient, living donor liver transplantation (LDLT) has become an universally used procedure. Small-for-size syndrome (SFSS) is a well-known complication after partial LT, especially in cases of adult-to-adult LDLT. The definition of SFSS slightly varies among transplant physicians. The use of a partial liver graft has risks of SFSS development. Persistent portal vein (PV) hypertension and PV hyper-perfusion after LT were identified as the main factors. Hence, various approaches were explored to modulate PV flow and decrease PV pressure in order to alleviate this syndrome. Herein, the definition, clinical symptoms, pathophysiology, basic research, as well as preventive and treatment strategies for SFSS are reviewed based on an extensive review of the literature and on our own experiences.

DATA SOURCES

The articles were collected through PubMed using search terms "liver transplantation", "living donor liver transplantation", "living liver donation", "partial graft", "small-for-size graft", "small-for-size syndrome", "graft volume", "remnant liver", "standard liver volume", "graft to recipient body weight ratio", "sarcopenia", "porcine", "swine", and "rat". English publications published before March 31, 2020 were included in this review.

RESULTS

Many transplant surgeons performed PV flow modulation, including portocaval shunt, splenic artery ligation and splenectomy. With these techniques, patient outcome has been improved even when using a "small" graft. Other factors, such as preoperative recipients' nutritional and skeletal muscle status, graft congestion, and donor factors, were also identified as risk factors which all have been addressed using various strategies.

CONCLUSIONS

The surgical approach controlling PV flow and pressure could help to prevent SFSS especially in severely ill recipients. In the absence of efficacious medications to resolve SFSS, conservative treatments, including aggressive fluid balance correction for massive ascites, anti-microbiological therapy to prevent or control sepsis and intensive nutritional therapy, are all required if SFSS could not be prevented.

Living donor liver transplantation in small-for-size setting

Small-for-Size Syndrome (SFSS) is one of the most feared complication of adult split liver and living donor liver transplantation. SFSS stems from a disproportionate/excessive portal vein flow relative to the volume of the implanted liver graft, and is currently one of the major practical limits to partial liver grafts' transplantation. In the last few decades many graft inflow modulation (GIM) techniques have been proposed to curtail the portal vein flow, allowing for successful transplantation of small partial liver grafts. Graft inflow modulation techniques span from Splenic Artery Ligation (SAL), to Splenectomy, Porto-Systemic Shunts and the lately proposed Splenic Devascularization. A patient tailored approach balancing the risk of SFSS with GIM specific morbidity, is more important than identifying the ideal GIM technique. Here we summarize the most recently published data to provide general indications in the challenging preoperative choice of a GIM techniques.

Post-transplant inflow modulation for early allograft dysfunction after living donor liver transplantation

Background

To treat small-for-size syndrome (SFSS) after living donor liver transplantation (LDLT), many procedures were described for portal flow modulation before, during, or after transplantation. The selection of the procedure as well as the best timing remains controversial.

Case presentation

A 43-year-old female with end-stage liver disease underwent LDLT with extended left with caudate lobe graft from her donor who was her 41-year-old brother (graft volume/standard liver volume (GV/SLV), 35.7%; graft to recipient weight ratio (GRWR), 0.67%). During the surgery, splenectomy could not be performed owing to severe peri-splenic adhesions to avoid the ruined bleedings. The splenic artery ligation was not also completely done because it was dorsal to the pancreas and difficult to be approached. Finally, adequate portal vein (PV) inflow was confirmed after portal venous thrombectomy. As having post-transplant optional procedures that are accessible for PV flow modulation, any other procedures for PV modulation during LDLT were not done until the postoperative assessment of the graft function and PV flow for possible postoperative modulation of the portal flow accordingly. Postoperative PV flow kept as high as 30 cm/s. By the end of the 1st week, there was a progressive deterioration of the total bilirubin profile (peak as 19.4 mg/dL) and ascitic fluid amount exceeded 1000 mL/day. Therefore, splenic artery embolization was done effectively and safely on the 10th postoperative day (POD) to reverse early allograft dysfunction as PV flow significantly decreased to keep within 20 cm/s and serum total bilirubin levels gradually declined with decreased amounts of ascites below 500 mL on POD 11 and thereafter. The patient was discharged on POD 28 with good condition.

Conclusions

SFSS can be prevented or reversed by the portal inflow modulation, even by post-transplant procedure. This case emphasizes that keeping accessible angiographic treatment options for PV modulation, such as splenic artery embolization, after LDLT is quite feasible.

Current status of liver transplantation in Asia

In spite of early adoption of the brain death legislation, and all efforts at promoting deceased donation, various social, economic and cultural factors have acted as road blocks to the furthering of deceased donor liver transplantation (DDLT) in most Asian societies. On the other hand, Asian liver transplant centers have been the pioneers, innovators, and technical advancement catalysts for the world to follow, especially with regards to living donor liver transplantation (LDLT). With some high volume centers performing more than 200 LDLTs a year with good outcomes in the donor and recipient, techniques to expand the living donor pool have also been adopted like ABO-incompatible, paired exchange and dual lobe living donor liver transplants. Although large multicenter, and registry data as regards safety and outcomes of minimally invasive donor hepatectomy are awaited, expert centers have pioneered, and now regularly perform purely laparoscopic and robotic living donor hepatectomies, especially in Korea.

Prognostic index consisting of early post-transplant variables <2 weeks in adult living-donor liver transplantation

AIM

Six-month recipient mortality after adult-to-adult living-donor liver transplantation (LDLT) remains high. Early and accurate prediction of recipient outcome and continuous monitoring of recipient severity after surgery are both essential for guiding appropriate care. This study was designed to identify early post-transplant parameters associated with 6-month mortality, and thereby to construct a discriminatory prognostic index (PI).

METHODS

We retrospectively analyzed 400 consecutive primary adult-to-adult LDLTs in our center (2006-2017). Perioperative variables were comprehensively analyzed for their accuracy in predicting recipient mortality by comparing the area under the receiver operating characteristic (AUROC) of each factor.

RESULTS

The AUROCs of preoperative predictive factors, for example, Model for End-stage Liver Disease (MELD) score and donor age, were 0.56 and 0.64, respectively, whereas those of post-transplant platelet count (PLT), total bilirubin (T-BIL), and prothrombin time - international normalized ratio (INR) on postoperative day (POD)-7-14 were 0.71/0.84, 0.68/0.82, and 0.71/0.78, respectively. Logistic regression analysis provided a formula: PI_POD-14  = 3.39 + 0.12 × PLT_POD-14  - 0.09 × T-BIL_POD-14  - 1.23 × INR_POD-14 , indicating a high AUROC of 0.87. Recipient 6-month survival with PI_POD-14  < 2.38 (n = 173) was 71.7%, whereas that with PI_POD-14  ≥ 2.38 (n = 222) was 97.7% (P < 0.001). The AUROCs of PI_POD-7 were as high as 0.8 in the subgroups with younger donors (<50 years of age), right lobe grafts, ABO-identical/compatible combinations, or low MELD score (<20), indicating usefulness of PI to identify unexpectedly complicated cases within the first week.

CONCLUSIONS

A novel, post-transplant survival estimator, PI, accurately predicts recipient 6-month mortality within 1-2 weeks after adult LDLT. Daily monitoring of PI could facilitate early interventions including retransplantation in critically ill patients.

A systematic review of small for size syndrome after major hepatectomy and liver transplantation

BACKGROUND

Major hepatectomy (MH) and particular types of liver transplantation (LT) (reduced size graft, living-donor and split-liver transplantation) lead to a reduction in liver mass. As the portal venous return remains the same it results in a reciprocal and proportionate rise in portal venous pressure potentially resulting in small for size syndrome (SFSS). The aim of this study was to review the incidence, diagnosis and management of SFSS amongst recipients of LT and MH.

METHODS

A systematic review was performed in accordance with the 2010 Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The following terms were used to search PubMed, Embase and Cochrane Library in July 2019: ("major hepatectomy" or "liver resection" or "liver transplantation") AND ("small for size syndrome" or "post hepatectomy liver failure"). The primary outcome was a diagnosis of SFSS.

RESULTS

Twenty-four articles met the inclusion criteria and could be included in this review. In total 2728 patients were included of whom 316 (12%) patients met criteria for SFSS or post hepatectomy liver failure (PHLF). Of these, 31 (10%) fulfilled criteria for PHLF following MH. 8 of these patients developed intractable ascites alongside elevated portal venous pressure following MH indicative of SFSS.

CONCLUSION

SFSS is under-recognised following major hepatectomy and should be considered as an underlying cause of PHLF. Surgical and pharmacological therapies are available to reduce portal congestion and reverse SFSS.

Impact of middle hepatic artery reconstruction after living donor liver transplantation using the left lobe

INTRODUCTION

The aim of this study was to clarify the impact of middle hepatic artery reconstruction on the outcomes of duct-to-duct biliary anastomosis after living donor liver transplantation (LDLT) using the left lobe.

MATERIALS AND METHODS

Among 258 patients who underwent LDLT using the left lobe, 216 patients who underwent hepatic artery reconstruction and one hepatic duct reconstruction with duct-to-duct interrupted anastomosis were divided into three groups: Group A (n = 123), one arterial stump with left hepatic artery reconstruction; Group B (n = 32), two arterial stumps with only left hepatic artery reconstruction; and Group C (n = 61), two arterial stumps with reconstruction of the left and middle hepatic arteries. The outcomes after LDLT were compared among the three groups.

RESULTS

No hepatic artery complications occurred. Group B had a significantly greater incidence of anastomotic biliary stricture than Group C. A multivariate analysis with Cox regression revealed that being in Group B was the only significant independent risk factor for postoperative anastomotic biliary stricture after LDLT.

CONCLUSIONS

Middle and left hepatic artery reconstruction is safe in LDLT and may prevent biliary stricture caused by dual hepatic artery reconstruction when the graft has left and middle hepatic artery stumps.

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.

Is Portal Inflow Modulation Always Necessary for Successful Utilization of Small Volume Living Donor Liver Grafts?

Although the well-accepted lower limit of the graft-to-recipient weight ratio (GRWR) for successful living donor liver transplantation (LDLT) remains 0.80%, many believe grafts with lower GRWR may suffice with portal inflow modulation (PIM), resulting in equally good recipient outcomes. This study was done to evaluate the outcomes of LDLT with small-for-size grafts (GRWR <0.80%). Of 1321 consecutive adult LDLTs from January 2012 to December 2017, 287 (21.7%) had GRWR <0.80%. PIM was performed (hemiportocaval shunt [HPCS], n = 109; splenic artery ligation [SAL], n = 14) in 42.9% patients. No PIM was done if portal pressure (PP) in the dissection phase was <16 mm Hg. Mean age of the cohort was 49.3 ± 9.1 years. Median Model for End-Stage Liver Disease score was 14, and the lowest GRWR was 0.54%. A total of 72 recipients had a GRWR <0.70%, of whom 58 underwent HPCS (1 of whom underwent HPCS + SAL) and 14 underwent no PIM, whereas 215 had GRWR between 0.70% and 0.79%, of whom 51 and 14 underwent HPCS and SAL, respectively. During the same period, 1034 had GRWR ≥0.80% and did not undergo PIM. Small-for-size syndrome developed in 2.8% patients. Three patients needed shunt closure at 1 and 4 weeks and 60 months. The 1-year patient survival rates were comparable. In conclusion, with PIM protocol that optimizes postperfusion PP, low-GRWR grafts can be used for appropriately selected LDLT recipients with acceptable outcomes.

Bilateral proficiency over time leads to reduced donor morbidity in living donor hepatectomy

Background

Although left-lobe donation is considered safer, right-sided donor hepatectomy predominates in adult living donor liver transplantation (LDLT). We hypothesized that bilateral proficiency with donor hepatectomy reduces overall donor complications.

Methods

A retrospective review of 834 adult LDLT donors (221 left lobes) from January 2004 to December 2014 was performed, dividing cases into two eras based on left-graft experience. Donor complications within 6 months were investigated, focusing on graft side and surgical era.

Results

The overall complication rate was 17.6%, and was higher in right-lobe donors. In Era 2, during which left-lobe donation rates were three times higher, total complications decreased (14.7% vs. 20.9%, P=0.02). A significant reduction in postoperative ascites accounted for the lower overall complication rate. The proportion of major biliary complications (BCs) was halved from 62.5% to 25.0%. Right-lobe donor complications also decreased significantly (15.8% vs. 22.9%, P=0.032), demonstrating that it was not only increased left-lobe donations leading to lowered complication rates, but also greater experience with donor hepatectomy in general.

Conclusions

Accumulating experience with bilateral donor hepatectomy leads to decreased donor morbidity and comparable outcomes for right and left lobes, further enhancing the goal of donor safety while balancing recipient needs.

Remnant Liver-to-Standard Liver Volume Ratio Below 40% is Safe in Ex Vivo Liver Resection and Autotransplantation

BACKGROUND

The successful application of ex vivo liver resection and autotransplantation (ERAT) has gained widespread attention for the treatment of end-stage hepatic alveolar echinococcosis, which is considered to be unresectable by conventional methods due to extensive invasion of the extra- and intrahepatic vasculature. However, data on remnant liver volume (RLV) are limited, and the safe volume limit of remnant liver is still unclear.

METHODS

To determine the effect of liver volume in the technically developed era, we investigated the impact of the remnant liver-to-standard liver volume ratio (RLV/SLV) on the outcomes of ERAT.

RESULTS

From February 2014 to May 2018, 56 ERAT procedures were performed. Eleven patients with an RLV/SLV < 40% (group S) were compared with 45 patients with an RLV/SLV ≥ 40% (group L). Serial changes in postoperative serum total bilirubin, alanine aminotransferase, aspartate aminotransferase, and international normalized ratio were comparable in both groups. The incidences of postoperative complications did not significantly differ between the two groups. Three patients died of intra-abdominal bleeding, acute cerebral hemorrhage, and severe liver dysfunction. In RLV estimation analysis, the actual RLV and RLV/SLV were significantly smaller than the expected RLV and RLV/SLV as determined by preoperative three-dimensional reconstruction software in patients with hepatic venous outflow obstruction.

CONCLUSION

Patients with a smaller RLV/SLV did not have outcomes inferior to those with a larger RLV/SLV. Further studies are warranted to clarify the factors that contribute to preoperative volumetric estimation and the safe lower limits for ERAT.

Secondary non-resectable liver tumors: A single-center living-donor and deceased-donor liver transplantation case series

BACKGROUND

During the last decades, deceased-donor liver transplantation (DDLT) has gained a place in the therapeutic algorithm of well-selected patients harbouring non-resectable secondary liver tumors. Living-donor LT (LDLT) might represent a valuable means to further expand this indication for LT.

METHODS

Between 1985 and 2016, twenty-two adults were transplanted because of neuroendocrine (n = 18, 82%) and colorectal metastases (n = 4, 18%); 50% received DDLT and 50% LDLT. In LDLT, 4 (36%) right and 7 (64%) left grafts were used; the median graft-to-recipient-weight ratios (GRWR) were 1.03% (IQR 0.86%-1.30%) and 0.59% (IQR 0.51%-0.91%), respectively. Median post-LT follow-up was 64 months (IQR 17-107) in the DDLT group and 40 months (IQR 35-116) in the LDLT group. DDLT and LDLT recipients were compared in terms of overall survival, graft survival, postoperative complications and recurrence.

RESULTS

The 1- and 5-year actuarial patient survivals were 82% and 55% after DDLT, 100% and 100% after LDLT, respectively (P < 0.01). One- and 5-year actuarial graft survivals were 73% and 36% after DDLT, 91% and 91% after LDLT (P < 0.01). The outcomes of right or left LDLT were comparable. Donor hepatectomy proved safe, and one donor experienced a Clavien IIIb complication. Bilirubin peak was significantly lower after left hepatectomy compared with that after right hepatectomy [1.3 (IQR 1.2-2.2) vs. 3.3 (IQR 2.3-5.2) mg/dL; P = 0.02].

CONCLUSIONS

The more recent LDLT series compared favorably to our DDLT series in the treatment of secondary liver malignancies. The absence of portal hypertension and the use of smaller left grafts make recipient and donor surgeries safe. The safety of the procedures and lack of interference with the scarce allograft pool are expected to lead to a more frequent use of LDLT in the field of transplant oncology.

Impact of small-for-size liver grafts on medium-term and long-term graft survival in living donor liver transplantation: A meta-analysis

BACKGROUND

Small-for-size grafts (SFSGs) in living donor liver transplantation (LDLT) could optimize donor postoperative outcomes and also expand the potential donor pool. Evidence on whether SFSGs would affect medium-term and long-term recipient graft survival is lacking.

AIM

To evaluate the impact of small-for-size liver grafts on medium-term and long-term graft survival in adult to adult LDLT.

METHODS

A systematic review and meta-analysis were performed by searching eligible studies published before January 24, 2019 on PubMed, EMBASE, and Web of Science databases. The primary outcomes were 3-year and 5-year graft survival. Incidence of small-for-size syndrome and short term mortality were also extracted.

RESULTS

This meta-analysis is reported according to the guidelines of the PRISMA 2009 Statement. Seven retrospective observational studies with a total of 1821 LDLT recipients were included in the meta-analysis. SFSG is associated with significantly poorer medium-term graft survival. The pooled odds ratio for 3-year graft survival was 1.58 [95% confidence interval 1.10-2.29, P = 0.014]. On the other hand, pooled results of the studies showed that SFSG had no significant discriminatory effect on 5-year graft survival with an odds ratio of 1.31 (95% confidence interval 0.87-1.97, P = 0.199). Furthermore, incidence of small-for-size syndrome detected in recipients of SFSG ranged from 0-11.4% in the included studies.

CONCLUSION

SFSG is associated with inferior medium-term but not long-term graft survival. Comparable long-term graft survival based on liver graft size shows that smaller grafts could be accepted for LDLT with appropriate flow modulatory measures. Close follow-up for graft function is warranted within 3 years after liver transplantation.

Naturally-Derived Biomaterials for Tissue Engineering Applications

Naturally-derived biomaterials have been used for decades in multiple regenerative medicine applications. From the simplest cell microcarriers made of collagen or alginate, to highly complex decellularized whole-organ scaffolds, these biomaterials represent a class of substances that is usually first in choice at the time of electing a functional and useful biomaterial. Hence, in this chapter we describe the several naturally-derived biomaterials used in tissue engineering applications and their classification, based on composition. We will also describe some of the present uses of the generated tissues like drug discovery, developmental biology, bioprinting and transplantation.

Adult-to-adult living-donor liver transplantation: The experience of the Université catholique de Louvain

BACKGROUND

Liver transplantation is the treatment for end-stage liver diseases and well-selected malignancies. The allograft shortage may be alleviated with living donation. The initial UCLouvain experience of adult living-donor liver transplantation (LDLT) is presented.

METHODS

A retrospective analysis of 64 adult-to-adult LDLTs performed at our institution between 1998 and 2016 was conducted. The median age of 29 (45.3%) females and 35 (54.7%) males was 50.2 years (interquartile range, IQR 32.9-57.5). Twenty-two (34.4%) recipients had no portal hypertension. Three (4.7%) patients had a benign and 33 (51.6%) a malignant tumor [19 (29.7%) hepatocellular cancer, 11 (17.2%) secondary cancer and one (1.6%) each hemangioendothelioma, hepatoblastoma and embryonal liver sarcoma]. Median donor and recipient follow-ups were 93 months (IQR 41-159) and 39 months (22-91), respectively.

RESULTS

Right and left hemi-livers were implanted in 39 (60.9%) and 25 (39.1%) cases, respectively. Median weights of right- and left-liver were 810 g (IQR 730-940) and 454 g (IQR 394-534), respectively. Graft-to-recipient weight ratios (GRWRs) were 1.17% (right, IQR 0.98%-1.4%) and 0.77% (left, 0.59%-0.95%). One- and five-year patient survivals were 85% and 71% (right) vs. 84% and 58% (left), respectively. One- and five-year graft survivals were 74% and 61% (right) vs. 76% and 53% (left), respectively. The patient and graft survival of right and left grafts and of very small (<0.6%), small (0.6%-0.79%) and large (≥0.8%) GRWR were similar. Survival of very small grafts was 86% and 86% at 3- and 12-month. No donor died while five (7.8%) developed a Clavien-Dindo complication IIIa, IIIb or IV. Recipient morbidity consisted mainly of biliary and vascular complications; three (4.7%) recipients developed a small-for-size syndrome according to the Kyushu criteria.

CONCLUSIONS

Adult-to-adult LDLT is a demanding procedure that widens therapeutic possibilities of many hepatobiliary diseases. The donor procedure can be done safely with low morbidity. The recipient operation carries a major morbidity indicating an important learning curve. Shifting the risk from the donor to the recipient, by moving from the larger right-liver to the smaller left-liver grafts, should be further explored as this policy makes donor hepatectomy safer and may stimulate the development of transplant oncology.

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.

Outcomes of right-lobe and left-lobe living-donor liver transplantations using small-for-size grafts

AIM

To analyze the outcomes of living-donor liver transplantation (LDLT) using left-lobe (LL) or right-lobe (RL) small-for-size (SFS) grafts.

METHODS

Prospectively collected data of adult patients who underwent LDLT at our hospital in the period from January 2003 to December 2013 were reviewed. The patients were divided into the RL-LDLT group and the LL-LDLT group. The two groups were compared in terms of short- and long-term outcomes, including incidence of postoperative complication, graft function, graft survival, and patient survival. A SFS graft was defined as a graft with a ratio of graft weight (GW) to recipient standard liver volume (RSLV) (GW/RSLV) of < 50%. The Urata formula was used to estimate RSLV.

RESULTS

Totally 218 patients were included for analysis, with 199 patients in the RL-LDLT group and 19 patients in the LL-LDLT group. The two groups were similar in terms of age (median, 53 years in the RL-LDLT group and 52 years in the LL-LDLT group, P = 0.997) but had significantly different ratios of men to women (165:34 in the RL-LDLT group and 8:11 in the LL-LDLT group, P < 0.0001). The two groups were also significantly different in GW (P < 0.0001), GW/RSLV (P < 0.0001), and graft cold ischemic time (P = 0.007). When it comes to postoperative complication, the groups were comparable (P = 0.105). Five patients died in hospital, 4 (2%) in the RL-LDLT group and 1 (5.3%) in the LL-LDLT group (P = 0.918). There were 38 graft losses, 33 (16.6%) in the RL-LDLT group and 5 (26.3%) in the LL-LDLT group (P = 0.452). The 5-year graft survival rate was significantly better in the RL-LDLT group (95.2% vs 89.5%, P = 0.049). The two groups had similar 5-year patient survival rates (RL-LDLT: 86.8%, LL-LDLT: 89.5%, P = 0.476).

CONCLUSION

The use of SFS graft in LDLT requires careful tailor-made surgical planning and meticulous operation. LL-LDLT can be a good alternative to RL-LDLT with similar recipient outcomes but a lower donor risk. Further research into different patient conditions is needed in order to validate the use of LL graft.

Preconditioning by portal vein embolization modulates hepatic hemodynamics and improves liver function in pigs with extended hepatectomy

BACKGROUND

Portal vein embolization is performed weeks before extended hepatic resections to increase the future liver remnant and prevent posthepatectomy liver failure. Portal vein embolization performed closer to the operation also could be protective, but worsening of portal hyper-perfusion is a major concern. We determined the hepatic hemodynamic effects of a portal vein embolization performed 24 hours prior to hepatic operation.

METHODS

An extended (90%) hepatectomy was performed in swine undergoing (portal vein embolization) or not undergoing (control) a portal vein embolization 24 hours earlier (n = 10/group). Blood tests, hepatic and systemic hemodynamics, hepatic function (plasma disappearance rate of indocyanine green), liver histology, and volumetry (computed tomographic scanning) were assessed before and after the hepatectomy. Hepatocyte proliferating cell nuclear antigen expression and hepatic gene expression also were evaluated.

RESULTS

Swine in the control and portal vein embolization groups maintained stable systemic hemodynamics and developed similar increases of portal blood flow (302 ± 72% vs 486 ± 92%, P = .13). Portal pressure drastically increased in Controls (from 9.4 ± 1.3 mm Hg to 20.9 ± 1.4 mm Hg, P < .001), while being markedly attenuated in the portal vein embolization group (from 11.4 ± 1.5 mm Hg to 16.1 ± 1.3 mm Hg, P = .061). The procedure also improved the preservation of the hepatic artery blood flow, liver function, and periportal edema. These effects occurred in the absence of hepatocyte proliferation or hepatic growth and were associated with the induction of the vasoprotective gene Klf2.

CONCLUSION

Portal vein embolization preconditioning represents a potential hepato-protective strategy for extended hepatic resections. Further preclinical studies should assess its medium-term effects, including survival. Our study also supports the relevance of hepatic hemodynamics as the main pathogenetic factor of post-hepatectomy liver failure.