"Reduced Size Liver Grafts in Pediatric Liver Transplantation; Technical Considerations".

Liver transplantation (LT) has become a vital treatment option for children with end-stage liver disease. Left lateral segment (LLS) grafts are particularly common in split and living donor LT for pediatric patients. However, challenges arise in small infants receiving LLS grafts, primarily due to graft-size mismatches, resulting in "large-for-size" grafts. To overcome this issue, the practice of further reducing grafts from the LLS to diminish graft thickness has been explored. Currently, the indication for reducing the thickness of LLS grafts includes recipients with a body weight (BW) under 5.0 kg, neonates with acute liver failure, or those with metabolic liver disease. At the National Center for Child Health and Development in Tokyo, Japan, among 131 recipients of reduced-size LLS grafts, a remarkable 15-year graft survival rate of 89.9% has been achieved in small infants. This success indicates that with experience and refinement of the technique, there's a trend towards improved graft survival in recipients with reduced-thickness LLS grafts. This advancement underscores the importance of BW-appropriate methods in graft selection to ensure exceptional outcomes in vulnerable pediatric patients in need of LT. These techniques' ongoing development and refinement are crucial in enhancing the survival rates and overall outcomes for these young patients.

Optimal graft size in pediatric living donor liver transplantation: How are children different from adults?

BACKGROUND: Pediatric liver transplantation is an established treatment for end-stage liver disease in children. However, it is still posing relevant challenges, such as optimizing the graft selection according to the recipient size. Unlike adults, small children tolerate large-for-size grafts and insufficient graft volume might represent an issue in adolescents when graft size is disproportionate. METHODS: Graft-size matching strategies over time were examined in pediatric liver transplantation. This review traces the measures/principles put in place to prevent large-for-size or small-for-size grafts in small children to adolescents with a literature review and an analysis of the data issued from the National Center for Child Health and Development, Tokyo, Japan. RESULTS: Reduced left lateral segment (LLS; Couinaud's segment II and III) was widely applicable for small children less than 5 kg with metabolic liver disease or acute liver failure. There was significantly worse graft survival if the actual graft-to-recipient weight ratio (GRWR) was less than 1.5% in the adolescent with LLS graft due to the small-for-size graft. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome. The suggested ideal graft selections in pediatric LDLT are: reduced LLS, recipient body weight (BW) < 5.0 kg; LLS, 5.0 kg ≤ BW < 25 kg; left lobe (Couinaud's segment II, III, IV with middle hepatic vein), 25 kg ≤ BW < 50 kg; right lobe (Couinaud's segment V, VI, VII, VIII without middle hepatic vein), 50 kg ≤ BW. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome. CONCLUSION: Age-appropriate and BW-appropriate strategies of graft selection are crucial to secure an excellent outcome in pediatric living donor liver transplantation.

The short- and long-term outcomes in living-donor liver transplantation using small-for-size graft: A systematic review and meta-analysis.

BACKGROUND: A standard graft-to-recipient weight ratio (GRWR) ≥0.8% is widely accepted in living-donor liver transplantation (LDLT); however, the potential donor pool is expanded to patients adopting small-for-size graft (SFSGs) with GRWR <0.8%. This study aimed to investigate the effect of SFSG on short- and long-term outcomes following LDLT. METHODS: Electronic databases were searched from January 1995 to January 2022 for studies comparing short- or long-term outcomes between patients with SFSG (GRWR <0.8%, SFSG group) and sufficient volume graft (GRWR ≥0.8%, non-SFSG group). The primary outcomes were one-, three-, and five-year overall survival (OS) and graft survival (GS), while the secondary outcome was postoperative complications. RESULTS: Twenty-four studies comprising 7996 patients were included. In terms of OS, SFSG group had poor three-year OS (HR: 1.48, 95% CI [1.01, 2.15], p = 0.04), but there were no significant differences between two groups in one-year OS (HR: 1.50, 95% CI [0.98, 2.29], p = 0.06) and five-year OS (HR: 1.40, 95% CI [0.95, 2.08], p = 0.02). In GS, there were no significant differences in one-year (HR 1.31, 95% CI [1.00, 1.72], p = 0.05), three-year (HR 1.33, 95% CI [0.97, 1.82], p = 0.07), and five-year GS (HR 1.17, 95% CI [0.95, 1.44], p = 0.13). The SFSG group had comparable postoperative complications, except for a high incidence of vascular complications and small-for-size syndromes. CONCLUSIONS: Expanding the potential donor pool in LDLT to SFSG with GRWR <0.8% can be acceptable in terms of comparable long-term OS and GS, despite the risk for vascular complications and small-for-size syndrome.

Small-For-Size Syndrome and Graft Inflow Modulation Techniques in Liver Transplantation.

BACKGROUND: Partial liver transplantation has recently been proposed to alleviate organ shortages. However, transplantation of a small-for-size graft is associated with an increased risk of posttransplant hepatic dysfunction, commonly referred to as small-for-size syndrome (SFSS). This review describes the etiology, pathological features, clinical manifestations, and diagnostic criteria of SFSS. Moreover, we summarize strategies to improve graft function, focusing on graft inflow modulation techniques. Finally, unmet needs and future perspectives are discussed. SUMMARY: In fact, posttransplant SFSS can be attributed to various factors such as preoperative status of the recipients, surgical techniques, donor age, and graft quality, except for graft size. With targeted improvement measures, satisfactory clinical outcomes can be achieved in recipients at increased risk of SFSS. Given the critical role of relative portal hyperperfusion in the pathogenesis of SFSS, various pharmacological and surgical treatments have been established to reduce or partially divert excessive portal inflow, and recipients will benefit from individualized therapeutic regimens after careful evaluation of benefits against potential risks. However, there remain unmet needs for further research into different aspects of SFSS to better understand the correlation between portal hemodynamics and patient outcomes. KEY MESSAGES: Contemporary transplant surgeons should consider various donor and recipient factors and develop case-specific prevention and treatment strategies to improve graft and recipient survival rates.

Successful living donor liver transplantation with a graft-to-recipient weight ratio of 0.41 without portal flow modulation: A case report.

BACKGROUND: There have been numerous efforts to lower the limit of minimum graft size to meet the metabolic demand of recipients in adult-to-adult living donor liver transplantation (LDLT). We experienced a successful case of LDLT using a very-small-for-size graft without portal flow modulation such as splenectomy or portocaval shunt. CASE SUMMARY: A 49-year-old man (weighing 91 kg) suffering hepatocellular carcinoma accompanied with hepatitis B virus related cirrhosis underwent LDLT. The one and only voluntary donor was his 17-year-old daughter whose body weight was 50 kg with a body mass index (BMI) of 18.3. The procured right liver graft was 411 g with a real graft-to-recipient weight ratio (GRWR) of 0.41%, the smallest to be reported in the literature. Both the recipient and donor had an uneventful recovery and were discharged on days 15 and 8, respectively, with normal liver function. The father and daughter have had no complication so far and are still in good health with normal liver function 81 mo after LDLT. CONCLUSION: Satisfactory outcomes can be achieved in LDLT with a GRWR as low as 0.41% even without using portal flow modulation in highly selected patients.

A systematic review of auxiliary liver transplantation of small-for-size grafts in patients with chronic liver disease.

Background & Aims: The shortage of liver grafts continues to worsen. Because the expanded use of small-for-size grafts (SFSGs) would substantially alleviate this shortage, we aimed to analyse the available knowledge on auxiliary liver transplantation (ALT) with SFSGs in patients with chronic liver disease (CLD) to identify opportunities to develop ALT with SFSGs in patients with CLD. Methods: This is a systematic review on ALT using SFSGs in patients with CLD. The review was completed by updates obtained from the authors of the retained reports. Results: Heterotopic ALT was performed in 26 cases between 1980 and 2017, none for SFGS stricto sensu, and auxiliary partial orthotopic liver transplantation (APOLT) in 27 cases (from 1999 to 2021), all for SFSG. In APOLT cases, partial native liver resection was performed in most of cases, whereas the second-stage remnant native liver hepatectomy was performed in 9 cases only. The median graft-to-body weight ratio was 0.55, requiring perioperative or intraoperative portal modulation in 16 cases. At least 1 complication occurred in 24 patients following the transplant procedure (morbidity rate, 89%). Four patients (4/27, 15%) died after the APOLT procedure. At the long term, 19 (70%) patients were alive and well at 13 months to 24 years (median, 4.5 years) including 18 with the APOLT graft in place and 1 following retransplantation. Conclusions: Despite high postoperative morbidity, and highly reported technical variability, the APOLT technique is a promising technique to use SFSGs in patients with CLD, achieving satisfactory long-term results. The results need to be confirmed on a larger scale, and a standardised technique could lead to even better results. Lay summary: At the cost of a high postoperative morbidity, the long-term results of APOLT for small-for-size grafts are good. Standardisation of the procedure and of portal modulation remain needed.

The impact of preformed donor-specific antibodies in living donor liver transplantation according to graft volume.

INTRODUCTION: The roles of preformed anti-HLA donor-specific antibodies (DSAs) in liver transplantation remain controversial. We evaluated the impact of preformed DSAs in living donor liver transplantation. METHODS: Adults who underwent living donor liver transplantation (n = 175) in our institute were included in this study. Lymphocyte cytotoxicity test (LCT), flow cytometric crossmatch (FCXM), and single-antigen bead assays were performed. RESULTS: Among adult living donor liver transplantation recipients, 27 (16.5%) and 14 (8.5%) had pretransplant FCXM-positive findings and LCT-positive findings, respectively. FCXM-positive patients displayed a significantly worse 5-year graft survival rate (77.3%; vs. DSA-negative, 91.6%). Six of 14 LCT-positive patients exhibited graft loss shortly after transplantation (5-year survival rate: 57.1%). All LCT-positive patients with graft loss underwent left lobe living donor liver transplantation. Significantly lower ratio of graft volume relative to standard liver volume (32.9 ± 5.7%) and smaller graft size (365.3 ± 57.9 g) were observed in patients with graft loss (p < .03, vs. surviving grafts). Significantly higher DSA-mean fluorescence intensity (MFI) values were present in patients with graft loss (p = .0012, vs. surviving grafts). CONCLUSIONS: Patients with preformed DSAs exhibited worse graft outcomes in living donor liver transplantation. Higher DSA-MFI values and smaller graft size were associated with worse outcomes in LCT-positive patients. High-risk patients with preformed DSAs should be considered for appropriate graft selection and application of a desensitization protocol.

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

AIM: Little evidence about whether to apply graft-to-recipient body weight ratio (GRWR) or graft weight to standard liver weight (GW/SLW) for graft selection has been published. The aim of the present study was to clarify the importance of the correct use of GRWR and GW/SLW for selecting graft according to the recipients' physique in living donor liver transplantation (LDLT). METHODS: Data were collected for 694 recipients who underwent LDLT between 1997 and 2020. RESULTS: One of the marginal grafts meeting GW/SLW ≥ 35% but GRWR < 0.7% has been used in more recipients with men and higher body mass index (BMI), and the other meeting GRWR ≥ 0.7% but GW/SLW < 35% has been used in more recipients with women with lower BMI. In the cohort of BMI > 30 kg/m2, the recipients with GRWR < 0.7% had a significantly higher incidence of small-for-size graft syndrome (SFSS) compared to those with GRWR ≥ 0.7% (P = 0.008, 46.2% vs 5.9%), and using the cutoff of GW/SLW < 35% could not differentiate. In contrast, in the cohort of BMI ≤ 30 kg/m2, the recipients with GW/SLW < 35% also had a significantly higher incidence of SFSS (P = 0.013, 16.9% vs 9.4%). Multivariate analysis showed that GRWR < 0.7% [odds ratio (OR) 14.145, P = 0.048] was the independent risk factor for SFSS in obese recipients, and GW/SLW < 35% [OR 2.685, P = 0.002] was the independent risk factor in non-obese recipients. CONCLUSION: Proper use of the formulas for calculating GRWR and GW/SLW in choosing graft according to recipient BMI is important, not only to meet metabolic demand for avoiding SFSS but also to ameliorate donor shortages.

Simultaneous splenectomy improves outcomes after adult living donor liver transplantation.

BACKGROUND & AIMS: Small-for-size graft (SFSG) syndrome is a major cause of graft loss after living donor liver transplantation (LDLT). Splenectomy (Spx) is an option to prevent this catastrophic complication, but its effect remains controversial. Herein, we aimed to elucidate the effect of simultaneous Spx on graft function and long-term outcomes after LDLT. METHODS: Three hundred and twenty patients were divided into 2 groups: those undergoing (n = 258) and those not undergoing (n = 62) simultaneous Spx. To overcome selection bias, propensity score matching (PSM) was performed (n = 50 in each group). RESULTS: Before PSM, recipients undergoing simultaneous Spx showed better graft function on post-operative day (POD) 7 and 14, as well as lower sepsis frequency within 6 months after LDLT and better graft survival rates compared to those not undergoing Spx. After PSM, compared to patients not undergoing Spx, those undergoing Spx had a lower frequency of early graft dysfunction on POD 7 (p = 0.04); a lower frequency of SFSG syndrome (p = 0.01), lower serum total bilirubin levels (p = 0.001), and lower international normalized ratio (p = 0.004) on POD 14; lower sepsis frequency within 6 months after LDLT (p = 0.02), and better graft survival rates (p = 0.04). Univariate analysis revealed that not undergoing Spx (hazard ratio 3.06; 95% CI 1.07-11.0; p = 0.037) was the only risk factor for graft loss after LDLT. CONCLUSIONS: Simultaneous Spx may prevent SFSG syndrome and is a predictive factor for graft survival after LDLT. Simultaneous Spx is recommended when a small graft (≤35% of standard liver weight) is predicted preoperatively, or for patients with portal hypertension or high portal pressure (above 20 mmHg) after reperfusion in LDLT. LAY SUMMARY: Living donor liver transplantation (LDLT) for patients with acute or chronic liver failure is an alternative to overcome the deceased donor shortage. The potential mismatch between graft and body size is a problem that needs to be solved for LDLT recipients. Herein, we evaluated the impact of simultaneous splenectomy and showed that it was associated with favorable outcomes in patients undergoing LDLT.

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.

[Impact of Non-middle Hepatic Vein Reconstruction on the Result of Low Graft-to-recipient Weight Ratio Living Donor Liver Transplantation].

OBJECTIVE: To analyze of the minimum graft-to-recipient weight ratio (GRWR) required for living donor liver transplantation (LDLT) without middle hepatic vein branch (MHVT) reconstruction. METHODS: We retrospectively collected the clinical data and outcomes of 303 LDLT patients over 16 years from 2001 to 2017. The minimum GRWR of non-middle hepatic vein reconstruction was analyzed by propensity score (PSM). RESULTS: With PSM analysis, no significant differences were observed in postoperative complications, SFSS, inpatient time, liver function, and coagulation function, but significant differences in 1-year, 3-year and 5-year survival between MHVT reconstruction and non-reconstruction group. The patients with MHVT reconstruction had better short-term and long-term survival than those without reconstruction. CONCLUSION: For LDLT patients without HMVT reconstruction, GRWR should be greater than 0.86%; for patients with HMVT reconstruction, GRWR is acceptable between 0.5% and 0.6%.

Outcomes of adult patients adopting small-for-size grafts in living donor liver transplantation: A systematic review and meta-analysis.

BACKGROUND: Small-for-size graft (SFSG) has emerged as one of the very contentions in adult-to-adult living donor liver transplantation (LDLT) as a certain graft size is related to recipients' prognosis. Graft-to-recipient weight ratio (GRWR) ≥0.8% was considered as a threshold to conduct LDLT. However, this also has been challenged over decades as a result of technique refinements. For a better understanding of SFSG in practice, we conducted this meta-analysis to compare the perioperative outcomes and long-term outcomes between patients adopting the grafts with a lower volume (GRWR < 0.8%, SFSG group) and sufficient volume (GRWR ≥ 0.8%, non-SFSG group) in adult-to-adult LDLT. DATA SOURCES: The studies comparing recipients adopting graft with a GRWR < 0.8% and ≥ 0.8% were searched by three authors independently in PubMed, Web of Science, Embase, the Cochrane Library, MEDLINE and Google Scholar databases until September 2018 and data were analyzed by RevMan 5.3.5. RESULTS: Sixteen studies with a total of 3272 subjects were included in this meta-analysis. In terms of small-for-size syndrome (SFSS), no significant difference was found in subjects enrolled after year 2010 (before 2010, OR=3.00, 95% CI: 1.69-5.35, P = 0.0002; after 2010, OR=1.23, 95% CI: 0.79-1.90, P = 0.36; P for interaction: 0.02). There was no significant difference in operative duration, blood loss, cold ischemia time, biliary complications, acute rejection, postoperative bleeding, hospitalization time, perioperative mortality, and 1-, 3- and 5-year overall survival rates between two groups. CONCLUSIONS: This meta-analysis suggested that adopting SFSG in adult LDLT has comparable outcomes to those with non-SFSG counterparts since 2010.

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.

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.

Living Donor Liver Transplantation Using Small-for-Size Grafts: Does Size Really Matter?

BACKGROUND: In living donor liver transplantation (LDLT), graft-to-recipient weight ratio (GRWR) > 0.8% is perceived as the critical graft size. This lower limit of GRWR (0.8%) has been challenged over the last decade owing to the surgical refinements, especially related to inflow and outflow modulation techniques. Our aim was to compare the recipient outcome in small-for-size (GRWR < 0.8) versus normal-sized grafts (GRWR > 0.8) and to determine the risk factors for mortality when small-for-size grafts (SFSG) were used. METHODS: Data of 200 transplant recipients and their donors were analyzed over a period of two years. Routine practice of harvesting middle hepatic vein (MHV) or reconstructing anterior sectoral veins into neo-MHV was followed during LDLT. Outcomes were compared in terms of mortality, hospital stay, ICU stay, and occurrence of various complications such as functional small-for-size syndrome (F-SFSS), hepatic artery thrombosis (HAT), early allograft dysfunction (EAD), portal vein thrombosis (PVT), and postoperative sepsis. A multivariate analysis was also done to determine the risk factors for mortality in both the groups. RESULTS: Recipient and donor characteristics, intraoperative variables, and demographical data were comparable in both the groups (GRWR < 0.8 and GRWR ≥ 0.8). Postoperative 90-day mortality (15.5% vs. 22.85%), mean ICU stay (10 vs. 10.32 days), and mean hospital stay (21.4 vs. 20.76 days) were statistically similar in the groups. There was no difference in postoperative outcomes such as occurrence of SFSS, HAT, PVT, EAD, or sepsis between the groups. Thrombosis of MHV/reconstructed MHV was a risk factor for mortality in grafts with GRWR < 0.8 but not in those with GRWR > 0.8. CONCLUSION: Graft survival after LDLT using a small-for-size right lobe graft (GRWR < 0.8%) is as good as with normal grafts. However, patency of anterior sectoral outflow by MHV or reconstructed MHV is crucial to maintain graft function when SFSG are used.

Impact of preserved collateral veins on small-for-size grafts in living donor liver transplantation.

AIM: Graft size is a critical issue in living donor liver transplantation (LDLT). We hypothesized that too much portal flow could possibly be diverted into pre-existing collateral veins, alleviating small-for-size syndrome (SFSS) in LDLT. This study evaluated the impact of the preserved collateral veins in the outcomes of LDLT using a small-for-size graft. METHODS: For patient safety, a graft-to-recipient weight ratio (GRWR) <0.8% was strictly confined to patients with collateral veins (group A), and the patient group was compared in a 1:3 ratio to a matched group of patients with GRWR ≥0.8% (group B) using propensity score analysis. RESULTS: Forty and 120 patients were included in group A and B, respectively. No significant differences in baseline patient characteristics were observed between the two groups except for graft weight and GRWR. The lowest GRWR was 0.4%. The graft portal inflow showed no significant differences for 7 days after graft implantation, ranging from 1668 to 5100 mL/min. Small-for-size syndrome occurred in no patients (0.0%) in group A and in 10 (8.3%) in group B (P = 0.067). Overall survival rates at 1, 3, and 5 years were not different between the two groups (85.0%, 82.5%, and 82.5% vs. 92.5%, 86.7%, and 85.0%, respectively; P = 0.670). CONCLUSION: Pre-existing collateral veins saved during surgery may have a reserve buffer for excessive portal flow to obviate SFSS in LDLT.