Liver transplantation in children with hyper-reduced grafts - a single-center experience

"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.

Reduced-Size Left Lateral Segment Grafts in Infants Weighing <10 kg

BACKGROUND

Live donor liver transplantation for infants weighing <10 kg has unique complexities, as patient/graft size discrepancies may cause vascular perfusion deficiencies. Failure of the abdominal closure further complicates this already challenging procedure. To overcome these potential problems, several techniques for graft size reduction-either anatomic or nonanatomic-have been proposed in the literature. Technically easier and less time-consuming, nonanatomic size reductions have the advantage of avoiding the risk of injury to the portal pedicle. This study aimed to evaluate and compare the effects of nonanatomic graft size reduction in infants weighing <10 kg with a large estimated preoperative graft recipient weight ratio.

METHODS

We enrolled 106 infants weighing <10 kg. Of these infants, 50 received reduced-size grafts. The outcomes were compared between the groups.

RESULTS

No difference was observed between the groups according to survival and vascular or biliary complications. None of the patients required an open abdomen or mesh closure.

CONCLUSION

Nonanatomic size reduction of left lateral segment grafts can be safely applied without compromising vascular supply, graft function, and patient survival with comparable vascular and biliary complication rates. This technique is safe and efficient in overcoming the complications caused by large-for-size syndrome in infants weighing <10 kg.

Outcome of split-liver transplantation from pediatric donors weighing 25 kg or less

The lower limit of body weight for "splitable" liver grafts remains unknown. To examine the outcome of split-liver transplantation (SLT) from pediatric donors ≤25 kg relative to conventional graft-type liver transplantation from deceased donors under corresponding conditions, a total of 158 patients who received primary liver transplantation, including 22 SLTs from donors ≤25 kg, 46 SLTs from donors >25 kg, 76 whole-liver transplantations, and 14 reduced-liver transplantations in donors ≤25 kg between January 2018 and December 2019, were included in the study. There was no significant difference in the complications, patient survival, and graft survival between each of the latter three groups and the SLT ≤25 kg group. Pediatric End-Stage Liver Disease (PELD) score was the independent predictor of graft loss (death or retransplantation). Graft weight was the independent predictor of hepatic artery thrombosis. SLT using well-selected pediatric donors ≤25 kg is an effective strategy to increase organ availability, especially for low-body-weight recipients, compared with conventional graft type from deceased donors under the condition of corresponding donor weight without increasing morbidity and mortality.

Large for size in pediatrics liver transplant using left lateral segment grafts: A single center experience

BACKGROUND

There are still controversies in using the large left lateral segment in pediatrics LT, with the possibility of the problem of LFS grafts, and the use of monosegmental or reduced liver grafts in small infants. This study aimed to evaluate our experience with LFSG in pediatrics LT.

METHODS

A cohort retrospective analysis was conducted including pediatric recipients who underwent LT between January 2011 and October 2019. We compared recipients with GRWR ≥ 4% (LFS) vs GRWR < 4% as an average for size grafts.

RESULTS

There were 331 pediatric LT, 74 patients with GRWR ≥ 4%, and 257 patients with GRWR < 4%. In the group of LFS grafts, temporary abdominal closure by silicon patch was done in 39 patients (52.7%), 2 patients (2.7%) had postoperative HAT, 3 patients (4.1%) early PVT, 1 patient (1.3%) bile leak, and 3 patients (4.1%) had wound infection, with no significant difference in these complications between the 2 groups. In patients with LFS- grafts, the 1-, 3-, 5-, and 7-year patients survival rates were 94.6%, 91.7%, 91.7%, and 91.7%, respectively, while the survival rates in patients of the other group were 96.1%, 92.6%, 91.9%, and 91.9%, respectively, with no significant difference (p = .85).

CONCLUSION

Using LFS graft by left lateral segment in pediatric LT with potential delayed abdominal closure is a safe and feasible option with good outcomes and unnecessary need for graft reduction if performed by an experienced multidisciplinary team.

Pediatric liver transplantation with hyperreduced left lateral segment graft

Backgrounds/Aims

To prevent large-for-size graft-related complications in small infant patients, the size of a left lateral segment (LLS) graft can be reduced to be a hyperreduced LLS (HRLLS) graft.

Methods

This study was intended to describe the detailed techniques for harvesting and implanting HRLLS grafts developed in a high-volume liver transplantation (LT) center.

Results

The mean recipient age was 4.0±1.7 months (range: 3-6) and body weight was 5.3±1.4 kg (range: 4.1-6.9). Primary diagnoses of the recipients were progressive familial intrahepatic cholestasis in 2 and biliary atresia in 1. The types of LT were living donor LT in 1 and split deceased donor LT in 2. Non-anatomical size reduction was performed to the transected LLS grafts. The mean weight of the HRLLS grafts was 191.7±62.1 g (range: 120-230) and graft-recipient weight ratio was 3.75±1.57% (range: 2.45-5.49). Widening venoplasty was applied to the graft left hepatic vein outflow orifice. Vein homograft interposition was used in a case with portal vein hypoplasia. Types of the abdomen wound closure were one case of primary repair, one of two-staged closure with a mesh, and one of three-staged repair with a silo and a mesh. All three patients recovered uneventfully from the LT operation and are doing well to date for more than 6 years after transplantation.

Conclusions

Making a HRLLS graft through non-anatomical resection during living donor LT and split deceased donor LT can be a useful option for treating small infant patients.

Pediatric split liver transplantation using a hyperreduced left lateral segment graft in an infant weighing 4 kg

We present a case of successful split liver transplantation (LT) using a hyperreduced left lateral segment (LLS) graft in a 106-day-old female infant patient weighing 4 kg. The patient was diagnosed with progressive familial intrahepatic cholestasis. Her general condition and liver function deteriorated progressively and she was finally allocated for a split LT under status 1. The deceased donor was a 20-year-old female weighing 63.7 kg. We performed in situ liver splitting and in situ size reduction sequentially. The weight of the hyperreduced LLS graft was 225 g, with a graft-recipient weight ratio of 5.5%. We performed recipient hepatectomy and graft implantation according to the standard procedures for pediatric living-donor LT. Since the graft was too large for primary abdomen closure, the abdominal wall was closed in three stages to make a prosthetic silo, temporary closure with a xenograft sheet, and final primary repair over 2 weeks. The patient has been doing well for more than 6 years after transplantation. In conclusion, split LT using a hyperreduced LLS graft can be a useful option for treating small infants. However, large-for-size graft-related problems, particularly in terms of graft thickness, still remain to be solved.

Short- and Long-Term Outcomes After Live-Donor Transplantation with Hyper-Reduced Liver Grafts in Low-Weight Pediatric Recipients

OBJECTIVE

To evaluate short- and long-term outcomes after live-donor liver transplantation (LT) with hyper-reduced grafts in low-weight pediatric recipients. LT is an established curative therapy for children with end-stage chronic liver disease or acute liver failure. A major problem in pediatric LT has been the lack of size-matched donor organs. The disadvantage of the use of large-for-size grafts is the insufficient tissue oxygenation and graft compression, which result in poor outcomes. The shortage of suitable donors is most notable in children under 10 kg. To overcome such obstacle, in situ hyper-reduced live-donor liver grafts have been introduced. Available articles in the literature are based on small samples and are deficient in long-term follow-up.

METHODS

A single-cohort, retrospective analysis was conducted including 59 pediatric patients under 10 kg who underwent hyper-reduced (in situ "a la carte" left lateral segment reduction) live-donor LT (LDLT) between February 1994 and February 2018.

RESULTS

The most frequent cause of liver failure was biliary atresia (70%). Median recipient weight was 8 kg. Vascular complications were confirmed in 15% of the sample, while 45% presented biliary complications. Median follow-up time was 40.3 months. Ten-year overall survival rate was 74%. Pediatric end-stage liver disease score > 23 was associated with a higher risk of post-operative complications.

CONCLUSION

LDLT can be undertaken in children with body weight < 10 kg achieving good results in high-volume centers by experienced surgeons.

Outcomes of Liver Transplantation in Small Infants

Liver transplantation (LT) for small infants remains challenging because of the demands related to graft selection, surgical technique, and perioperative management. The aim of this study was to evaluate the short-term and longterm outcomes of LT regarding vascular/biliary complications, renal function, growth, and patient/graft survival in infants ≤3 months compared with those of an age between >3 and 6 months at a single transplant center. A total of 64 infants ≤6 months underwent LT and were divided into 2 groups according to age at LT: those of age ≤3 months (range, 6-118 days; XS group, n = 37) and those of age >3 to ≤6 months (range, 124-179 days; S group, n = 27) between 1989 and 2014. Acute liver failure was the main indication for LT in the XS group (n = 31, 84%) versus S (n = 7, 26%). The overall incidence of hepatic artery thrombosis and portal vein thrombosis/stricture were 5.4% and 10.8% in the XS group and 7.4% and 11.1% in the S group, respectively (not significant). The overall incidence of biliary stricture and leakage were 5.4% and 2.7% in the XS group and 3.7% and 3.7% in the S group, respectively (not significant). There was no significant difference between the 2 groups in terms of renal function. No significant difference was found between the 2 groups for each year after LT in terms of height and weight z score. The 1-, 5-, and 10-year patient survival rates were 70.3%, 70.3%, and 70.3% in the XS group compared with 92.6%, 88.9%, and 88.9% in the S group, respectively (not significant). In conclusion, LT for smaller infants has acceptable outcomes despite the challenges of surgical technique, including vascular reconstruction and graft preparation, and perioperative management.

Biliary reconstruction before clamp removal to avoid portal vein thrombosis in pediatric living-donor liver transplantation using hyper-reduced left lateral segment grafts: A novel technical strategy

LT has become the treatment of choice for children with end-stage liver disease. The scarcity of donors and the considerable mortality on waiting lists have propelled the related living-donor techniques, especially in small children. This population need smaller and good quality grafts and are usually candidates to receive a LLS from a related donor. Many times this grafts are still large and do not fit in the receptor's abdomen, so a further hyper-reduction may be required. Despite all advances in LT field, vascular complications still occur in a considerable proportion remaining as a significant cause of morbidity, graft loss, and mortality. Technical issues currently play an essential role in its genesis. The widely spread technique for biliary and vascular reconstruction in living donor LT (LDLT) nowadays implies removal of the portal vein (PV) clamp after the venous anastomosis, then the arterial reconstruction is done, followed by the biliary reconstruction. However, due to the posterior location of the LLS bile duct, for its reconstruction, a rotation of the liver is required risking a potential transient PV occlusion leading to thrombosis afterward. We describe a new technique that involves performing biliary reconstruction after the PV anastomosis and before removing the vascular clamp, thus allowing to freely rotate the liver with less risk of PV occlusion and thrombosis.

Is size the only determinant of delayed abdominal closure in pediatric liver transplant?

The aim was to determine the factors associated with the use of delayed abdominal closure in pediatric liver transplantation (LT) and whether this affected outcome. From a prospectively maintained database, transplants performed in children (≤18 years) were identified (October 2010 to March 2015). Primary abdominal closure was defined as mass closure performed at time of transplant. Delayed abdominal closure was defined as mass closure not initially performed at the same time as transplant; 230 children underwent LT. Of these, 176 (76.5%) had primary closure. Age was similar between the primary and delayed groups (5.0 ± 4.9 versus 3.9 ± 5.0 years; P = 0.13). There was no difference in the graft-to-recipient weight ratio (GRWR) in the primary and delayed groups (3.4 ± 2.8 versus 4.1 ± 2.1; P = 0.12). Children with acute liver failure (ALF) were more likely to experience delayed closure then those with chronic liver disease (CLD; P < 0.001). GRWR was similar between the ALF and CLD (3.4 ± 2.4 versus 3.6 ± 2.7; P = 0.68). Primary closure children had a shorter hospital stay (P < 0.001), spent fewer days in pediatric intensive care unit (PICU; P = 0.001), and required a shorter duration of ventilation (P < 0.001). Vascular complications (arterial and venous) were similar (primary 8.2% versus delayed 5.6%; P = 0.52). Graft (P = 0.42) and child survival (P = 0.65) in the primary and delayed groups were similar. Considering timing of mass closure after transplant, patients in the early delayed closure group (<6 weeks) were found to experience a shorter time of ventilation (P = 0.03) and in PICU (P = 0.003). In conclusion, ALF was the main determinant of delayed abdominal closure rather than GRWR. The optimal time for delayed closure is within 6 weeks. The use of delayed abdominal closure does not adversely affect graft/child survival. Liver Transplantation 23 352-360 2017 AASLD.

Dorsal approach plus branch patch technique is the preferred method for liver transplanting small babies with monosegmental grafts

PURPOSE

When living donor liver transplantation (LDLT) is performed on small infant patients, the incidence of hepatic artery complications (HACs) is high. Here, we present a retrospective analysis that focuses on our surgical procedure for hepatic arterial reconstruction and the outcomes of monosegmental LDLT.

METHODS

Of the 275 patients who underwent LDLT between May 2001 and December 2015, 13 patients (4.7 %) underwent monosegmental LDLT. Hepatic artery reconstruction was performed under a microscope. The size discrepancy between the graft and the recipient's abdominal cavity was defined as the graft to recipient distance ratio (GRDR) between the left hepatic vein and the portal vein (PV) bifurcation on a preoperative computed tomography scan. HACs were defined as hepatic arterial hypoperfusion.

RESULTS

Recipient hepatic arteries were selected for the branch patch technique in five cases (38.5 %), and the diameter was 2.2 ± 0.6 mm. The anastomotic approaches selected were the dorsal position of the PV in seven cases (53.8 %) and the ventral position in six, and the GRDRs were 2.8 ± 0.4 and 1.9 ± 0.5, respectively (p = 0.012). The incidence rate of HACs caused by external factors, such as compression or inflammation around the anastomotic site, was significantly higher in monosegmental than in non-monosegmental graft recipients (15.4 vs. 1.1 %, p < 0.001).

CONCLUSION

Although monosegmental graft recipients experienced HACs caused by external factors around the anastomotic field, hepatic arterial reconstruction could be safely performed. Important components of successful hepatic arterial reconstructions include the employment of the branch patch technique and the selection of the dorsal approach.

Living-donor liver transplantation with hyperreduced left lateral segment grafts: a single-center experience

BACKGROUND

In the setting of liver transplantation in small infants who receive left lateral segment (LLS) grafts, problems are encountered related to graft-size mismatching in the form of so-called "large-for-size" grafts. To address these problems, the feasibility of further reducing the size of LLS grafts to form hyperreduced LLS (HRLLS) grafts was investigated.

METHODS

Of the 175 pediatric living-donor liver transplantations performed between November 2005 and December 2011 at our institute, 31 cases were performed using HRLLS grafts. The medical records were reviewed and data were collected retrospectively.

RESULTS

The graft-to-recipient body weight ratio was successfully reduced from 5.2% ± 2.0% to 2.9% ± 0.5%. Portal vein thrombosis was observed in one case, and biliary stenosis was seen in two cases. No hepatic artery thrombosis was encountered. The graft and patient 2-year survival rate was 87%. When the results categorized according to the original disease were verified, patients with fulminant hepatic failure (FHF) weighed less and had smaller abdominal cavities compared with patients with cholestatic or metabolic disease. Patients with FHF frequently required skin or partial skin closure to avoid graft compression. For this reason, the anteroposterior diameters in the recipients' abdominal cavities were not adequately large to accommodate the graft thickness, especially in patients with FHF.

CONCLUSIONS

In conclusion, living-donor liver transplantation using HRLLS grafts offers a safe and useful option for treating smaller infants.

Pediatric liver transplantation using reduced and hyper-reduced left lateral segment grafts: a 10-year single-center experience

Few studies have examined the long-term outcomes and prognostic factors associated with pediatric living living-donor liver transplantation (LDLT) using reduced and hyper-reduced left lateral segment grafts. We conducted a retrospective, single-center assessment of the outcomes of this procedure, as well as clinical factors that influenced graft and patient survival. Between September 2000 and December 2009, 49 patients (median age: 7 months, weight: 5.45 kg) underwent LDLT using reduced (partial left lateral segment; n = 5, monosegment; n = 26), or hyper-reduced (reduced monosegment grafts; n = 18) left lateral segment grafts. In all cases, the estimated graft-to-recipient body weight ratio of the left lateral segment was more than 4%, as assessed by preoperative computed tomography volumetry, and therefore further reduction was required. A hepatic artery thrombosis occurred in two patients (4.1%). Portal venous complications occurred in eight patients (16.3%). The overall patient survival rate at 1, 3 and 10 years after LDLT were 83.7%, 81.4% and 78.9%, respectively. Multivariate analysis revealed that recipient age of less than 2 months and warm ischemic time of more than 40 min affected patient survival. Pediatric LDLT using reduced and hyper-reduced left lateral segment grafts appears to be a feasible option with acceptable graft survival and vascular complication rates.

A formula for determining the standard liver volume in children: a special reference for neonates and infants

Accurately evaluating the ratio of GV to the SLV (GV/SLV) is important in successful pediatric liver transplantation. However, the formula used to calculate the SLV of children, including neonates and infants, has not yet been established. The aim of the current study was to estimate the SLV of children, including neonates, and to establish an accurate formula. The LV of 100 children (including 7 neonates and 15 infants) were measured using thin slice (3-5 mm) helical CT images. Their BSA was calculated from height and weight. A new formula to estimate the SLV was established as follows: SLV (mL) =689.9 × BSA (m(2)) -24.7. The SLV of children was significantly lower than that in previous reports (p < 0.001). A formula for calculating the SLV of children including neonates was established. This new formula will be useful in pediatric liver transplantation.

Implications for the usage of the left lateral liver graft for infants ≤10 kg, irrespective of a large-for-size situation--are monosegmental grafts redundant?

Organ donor shortage for infant liver transplant recipients has lead to an increase in splitting and living donation. For cases in which even transplantation of the left lateral graft (Couinaud's segments II + III) results in a "large for size situation" with an estimated graft body weight ratio (GBWR) of >4%, monosegmental liver transplantation was developed. This, however, bears complications because of greater parenchymal surface and suboptimal vascular flow. We exclusively use the left lateral graft from living donors or split grafts. Temporary abdominal closure is attempted in cases of increased pressure. We report of 41 pediatric transplants in 38 children ≤10 kg. Within this group, there were 23 cases with a GBWR of ≥4, and 15 cases with a GBWR <4. There was no statistical difference in vascular or biliary complications. Despite a more frequent rate of temporary abdominal closure, we did not find a higher rate of intra-abdominal infections. Overall, patient and graft survival was excellent in both groups (one death, three re-transplants). We noticed, however, that the ventro-dorsal diameter of the graft appears to be more relevant to potential graft necrosis than the actual graft size. In conclusion, the usage of monosegmental grafts seems unnecessary if transplantation of left lateral grafts is performed by an experienced multidisciplinary team, and temporary abdominal closure is favored in cases of increased abdominal pressure.