平田 雄大

小児肝移植患者は、成人に比べ、グラフト不全や患者予後に直結する血管合併症や重症感染症のリスクが高い。小児肝移植患者の呼吸管理では、術前からの呼吸器合併症、過大グラフト、術中のover volumeなどの影響で抜管は遅れる傾向にある。また抜管可能であっても、術後に肝血流障害を認める症例では、肝血流が安定するまで抜管を遅らせるのが望ましい。循環管理では血管内脱水による肝機能障害や血栓症を防ぐため、心肺機能が許す範囲でハイドレーションをかける。大量腹水をもたらす重症急性拒絶反応の出現に注意する。肝移植周術期の敗血症は重篤であるため、発熱時の速やかな起炎菌・感染源の同定と抗菌薬治療、術後早期経腸栄養による感染症の予防が重要である。低体重の新生児や乳児における肝移植の成否には、肝移植のあらゆる術後合併症を理解し、新生児への血液浄化療法に精通したICU、PICUのスタッフの存在が不可欠である。(著者抄録)

The serum ferritin (SF) concentration is a widely available and objective laboratory parameter. SF is also widely recognized as an acute-phase reactant. The purpose of the present study was to identify the chronological changes in the recipient's SF concentration during liver transplantation (LT) and to clarify factors having an effect on the recipient's intraoperative SF level. In addition, the study retrospectively evaluated the usefulness of measuring SF during LT. Ninety-eight pediatric recipients were retrospectively analyzed. The data were analyzed and compared according to the SF level in the recipient. Patients were classified into 2 groups based on the intraoperative peak SF levels of ≤ 1000 ng/mL (low-SF group) or >1000 ng/mL (high-SF group). The SF value increased dramatically after reperfusion and fell to normal levels within the early postoperative period. The warm ischemia time (WIT) was significantly longer in the high-SF group (47.0 versus 58.5 minutes; P = 0.003). In addition, a significant positive correlation was observed between the peak SF value and WIT (r = 0.35; P < 0.001). There were significant positive correlations between the peak SF value and the donors' preoperative laboratory data, including transaminases, cholinesterase, hemoglobin, transferrin saturation, and SF, of which SF showed the strongest positive correlation (r = 0.74; P < 0.001). The multivariate analysis revealed that WIT and donor's SF level were a significant risk factor for high SF level in the recipient (P = 0.007 and 0.02, respectively). In conclusion, the SF measurement can suggest the degree of ischemia/reperfusion injury (IRI). A high SF level in the donor is associated with the risk of further acute reactions, such as IRI, in the recipient.

小児肝移植における服薬アドヒアランスの現状と課題について検討した。肝移植を施行した中学生以上で移植後1年以上経過した125例(男性48名、女性77名、現年齢13〜37歳、移植時0.8〜22.6歳)を対象とした。電子カルテに記載された内容をもとに後方視的に収集した。服薬アドヒアランス良好群は83例、服薬ノンアドヒアランス群は42例であった。服薬ノンアドヒアランス群において、移植時年齢と現年齢は有意に高く、服薬数に関しては、免疫抑制薬服薬数と全服薬数が有意に多かった。服薬ノンアドヒアランス群において有意に肝機能障害を認め、グラフト不全症例が多い傾向にあった。免疫抑制薬3剤内服開始時年齢は服薬ノンアドヒアランス群で高い傾向にあり、服薬ノンアドヒアランス群20例の全例に肝機能障害を認めた。社会的背景に関しては、服薬ノンアドヒアランス群において不定期通院、内服自己管理、家庭環境・家族形態の変化、不快な服薬体験を有意に多く認めた。現年齢19歳以上、移植時年齢中学生以上において服薬ノンアドヒアランス率は有意に高かった。

BACKGROUND: Hepatocellular nodules caused by congenital extrahepatic portosystemic shunts (CEPS) occur as a result of abnormal portal blood flow, and are mostly cases of benign focal nodular hyperplasia (FNH). However, hepatocellular adenomas (HCA) and hepatocellular carcinomas have been documented in the CEPS patients. HCA can now be immunohistochemically diagnosed; therefore, the concept of hepatocellular nodules resulting from CEPS should be revisited. In this study, we performed a retrospective immunohistochemical investigation of hepatocellular nodules from livers isolated from the CEPS patients undergoing living donor liver transplantation (LDLT). METHODS: Hepatocellular nodules from livers of five patients with CEPS who underwent LDLT between June 2004 and October 2012 at our institution were immunohistochemically investigated. HCA were classified into four subtypes (HNF1α-inactivated HCA (H-HCA); inflammatory HCA; β-catenin-activated HCA (b-HCA); unclassified HCA). RESULTS: Sixteen hepatocellular nodules were collected from livers of five patients with CEPS who underwent LDLT. Ten hepatocellular nodules were categorized as FNH (62.5%), five were categorized as b-HCA (31.3%), and one was categorized as H-HCA (6.2%). CONCLUSIONS: Some of the hepatocellular nodules resulting from CEPS were indicative of HCAs, especially the b-HCA subtype which has the potential for malignant transformation. Surgical or interventional treatments might have to be performed when hepatocellular nodules appear in the CEPS patients.

Studies suggest that prophylactic intra-abdominal drains are unnecessary for cadaveric liver transplantation using whole liver grafts because there is no benefit from drainage. However, no studies have investigated on the necessity of prophylactic drains after LDLT using split-liver grafts or reduced-liver grafts, which may present a high risk of post-transplant intra-abdominal infections. This retrospective study investigated whether the ascitic data on POD 5 after LDLT can predict intra-abdominal infections and on the post-transplant management of prophylactic drains. Between March 2008 and March 2013, 90 LDLTs were performed. We assessed the number of ascitic cells, biochemical examinations, and cultivation tests at POD1 and POD5. The incidence rates of post-transplant intra-abdominal infections were 24.4%. The multivariate analysis showed that left lobe and S2 monosegment grafts were a significant risk factor for intra-abdominal infections (p = 0.006). The patients with intra-abdominal infections had significantly higher acsitic LDH levels and the positive rate of ascitic culture at POD5 in comparison with patients without infections (p < 0.001 and p = 0.014, respectively). LDLT using left lobe and S2 monosegment grafts yields a high risk for post-transplant intra-abdominal infections, and ascitic LDH and cultivation tests at POD5 via prophylactic drains can predict intra-abdominal infections.

BACKGROUND: Although endotoxin (Et) has been used as a biological index of bacterial infections, Et can also be used to evaluate liver functions because Et present in the portal vein blood is processed by the hepatic reticuloendothelial system. In the field of posttransplant management, it is important for liver transplant recipients to monitor the presence of posttransplant bacterial infections and graft liver functions because these results are directly correlated with a graft prognosis. Therefore, the measurement of Et during liver transplantation (LT) may be the detection of posttransplant infections and graft liver functions. This retrospective study investigated whether Et measured by the Et activity assay (EAA) in the peripheral venous blood during living donor LT (LDLT) can predict the incidence of posttransplant bacterial infections and graft liver functions. MATERIALS AND METHODS: The study subjects consisted of 21 patients who underwent LDLT between April 2010 and February 2011. Et activity (EA) was measured using the EAA in peripheral venous blood samples collected 1 or 2 days before LDLT, and on postoperative days (PODs) 1, 5, 7, and 14. We included LDLT recipients with intra-abdominal infections, respiratory infections, and bacteremia in the group with posttransplant bacterial infections. RESULTS: The incidence rates of posttransplant bacterial infections or hyperbilirubinemia after LDLT were 57.1%. The LDLT recipients with posttransplant bacterial infections or hyperbilirubinemia had significantly higher levels of EA in comparison with patients without complications before LDLT (0.22 ± 0.10 vs. 0.07 ± 0.05, p < 0.001), but they had no statistically significant increase of EA between PODs 1 and 14. Based on a receiver operating characteristic curve analysis of pretransplant levels of EA in patients with posttransplant bacterial infections or hyperbilirubinemia, the recommended cutoff value to diagnose posttransplant bacterial infections or hyperbilirubinemia was set at 0.16 (sensitivity 83.3%, specificity 88.9%, and area under the curve 0.940). CONCLUSION: At a pretransplant level of EA greater than 0.16, patients had an augmented risk for developing posttransplant bacterial infections or hyperbilirubinemia.

Previous studies have demonstrated the safety of ABO-incompatible pediatric LDLT using preoperative plasmapheresis and rituximab; however, no reports have described the timing and dosage of rituximab administration for pediatric LDLT. This study aimed to describe a safe and effective dosage and timing of rituximab for patients undergoing pediatric ABO-incompatible LDLT based on the experience of our single center. A total of 192 LDLTs in 187 patients were examined. These cases included 29 ABO-incompatible LDLTs in 28 patients. Rituximab was used beginning in January 2004 in recipients older than two yr of age (first period: 375 mg/m(2) in two cases; second period: 50 mg/m(2) in two cases; and 200 mg/m(2) in eight cases). Two patients who received 375 mg/m(2) rituximab died of Pneumocystis carinii pneumonia and hemophagocytic syndrome. One patient who received 50 mg/m(2) rituximab required retransplantation as a consequence of antibody-mediated complications. All eight patients administered 200 mg/m(2) survived, and the mean CD20(+) lymphocyte count was 0.1% at the time of LDLT. In the preoperative management of patients undergoing pediatric ABO-incompatible LDLT, the administration of 200 mg/m(2) rituximab three wk prior to LDLT was safe and effective.

In the field of pediatric living donor liver transplantation (LDLT), physicians sometimes must reduce the volume of left lateral segment (LLS) grafts to prevent large-for-size syndrome. There are 2 established methods for decreasing the size of an LLS graft: the use of a segment 2 (S2) monosegment graft and the use of a reduced LLS graft. However, no procedure for selecting the proper graft type has been established. In this study, we conducted a retrospective investigation of LDLT and examined the strategy of graft selection for patients weighing ≤6 kg. LDLT was conducted 225 times between May 2001 and December 2012, and 15 of the procedures were performed in patients weighing ≤6 kg. We selected S2 monosegment grafts and reduced LLS grafts if the preoperative computed tomography (CT)-volumetry value of the LLS graft was >5% and 4% to 5% of the graft/recipient weight ratio, respectively. We used LLS grafts in 7 recipients, S2 monosegment grafts in 4 recipients, reduced S2 monosegment grafts in 3 recipients, and a reduced LLS graft in 1 recipient. The reduction rate of S2 monosegment grafts for use as LLS grafts was 48.3%. The overall recipient and graft survival rates were both 93.3%, and 1 patient died of a brain hemorrhage. Major surgical complications included hepatic artery thrombosis in 2 recipients, bilioenteric anastomotic strictures in 2 recipients, and portal vein thrombosis in 1 recipient. In conclusion, our graft selection strategy based on preoperative CT-volumetry is highly useful in patients weighing ≤6 kg. S2 monosegment grafts are effective and safe in very small infants particularly neonates.

The use of donors with coagulation FIX deficiency is controversial, and there are no current protocols for peri-transplant management. We herein describe the first reported case of a pediatric LDLT from an asymptomatic donor with mild coagulation FIX deficiency. A 32-yr-old female was evaluated as a donor for her 12-month-old daughter with biliary atresia. The donor's pretransplant coagulation tests revealed asymptomatic mild coagulation FIX deficiency (FIX activity 60.8%). Freeze-dried human blood coagulation FIX concentrate was administered before the dissection of the liver and 12 h afterwards by bolus infusion (40 U/kg) and was continued on POD 1. The bleeding volume at LDLT was 590 mL. On POD 1, 3, 5, and 13, the coagulation FIX activity of the donor was 121.3%, 130.6%, 114.6%, and 50.2%, respectively. The donor's post-transplant course was uneventful, and the recipient is currently doing well at 18 months after LDLT. The FIX activity of the donor and recipient at nine months after LDLT was 39.2% and 58.0%, respectively. LDLT from donors with mild coagulation FIX deficiency could be performed effectively and safely using peri-transplant short-term coagulation FIX replacement and long-term monitoring of the plasma FIX level in the donor.

Background/Aims: (beta-D glucan in the portal vein blood is processed by the hepatic reticuloendothelial system, and therefore, it is possible that the beta-D glucan kinetics of the peripheral vein blood may be useful as a biological index. In this study, the beta-D glucan levels in the peripheral and portal vein blood during liver transplantation were measured in order to study the clinical significance of the molecule. Methodology: The subjects comprised 20 patients who underwent living donor liver transplantation. In the perioperative period, the beta-D glucan levels were measured before liver transplantation, during surgical procedure, then on postoperative days 5, 14, and 21. Results: The portal vein blood showed a significantly higher level beta-D glucan than the peripheral blood (p&lt;0.001). A significant difference of beta-D glucan levels was observed between the pre-liver transplantation and postoperative days 5 (p=0.048). There was a significant positive correlation between the preoperative beta-D glucan level and the period of postoperative hospitalization (p&lt;0.001). The patients with fungal infections (35.0%) had a significantly longer period of hospitalization.(p=0.019). Conclusions: The beta-D glucan kinetics accurately reflects the liver function and fungal infections. The beta-D glucan level before liver transplantation can be used to predict the period of hospitalization.

BACKGROUND: Hepatic artery complications (HAC) are a serious complication in pediatric liver transplant recipients because its incidence is high and it can occasionally lead to graft liver failure. We herein present a retrospective analysis of our 10-year experience with pediatric living donor liver transplantation (LDLT) focusing on the risk factors and treatments for HAC. METHODS: Between May 2001 and November 2011, 209 LDLTs were performed for 203 pediatric recipients. We performed the multivariate analyses to identify the factors associated with HAC and showed the therapeutic strategy and outcome for HAC. RESULTS: The overall incidence of HAC was 7.2%, and the graft survival of recipients with HAC was 73.3%. The multivariate analysis showed that the pediatric end-stage liver disease score (≥20), post-transplant laparotomy except for HAC treatment and extra-anatomical hepatic artery reconstruction were independent risk factors for HAC (P = 0.020, P = 0.015 and P = 0.002, respectively). Eleven surgical interventions and 13 endovascular interventions were performed for 15 recipients with HAC. The serum aspartate aminotransferase levels pre- and post-treatment for HAC were significantly higher in the surgical group than in the endovascular group (P = 0.016 and P = 0.022, respectively). CONCLUSIONS: It is important for recipients with risk factors to maintain strict post-transplant management to help prevent HAC and detect it in earlier stages. Endovascular intervention can be a less invasive method for treating HAC than surgical intervention, and can be performed as an early treatment.

AIM: To assessed the clinical significance of protocol liver biopsy (PLB) in pediatric liver transplantation (LT). METHODS: Between July 2008 and August 2012, 89 and 55 PLBs were performed in pediatric patients at two and five years after LT, respectively. We assessed the histopathological findings using the Metavir scoring system, including activity (A) and fibrosis (F), and we identified factors associated with scores of ≥ A1 and ≥ F1. Our results clarified the timing and effectiveness of PLB. RESULTS: The incidences of scores of ≥ A1 and ≥ F1 were 24.7% and 24.7%, respectively, at two years after LT and 42.3% and 34.5%, respectively, at five years. Independent risk factors in a multivariate analysis of a score of ≥ A1 at two years included ≥ 2 h of cold ischemic time, no acute cellular rejection and an alanine amino transaminase (ALT) level of ≥ 20 IU/L (P = 0.028, P = 0.033 and P = 0.012, respectively); however, no risk factors were identified for a score of ≥ F1. Furthermore, no independent risk factors associated with scores of ≥ A1 and ≥ F1 at five years were identified using multivariate analysis. A ROC curve analysis of ALT at two years for a score of ≥ A1 demonstrated the recommended cutoff value for diagnosing ≥ A1 histology to be 20 IU/L. The incidence of scores of ≥ A2 or ≥ F2 at two years after LT was 3.4% (three cases), and all patients had an absolute score of ≥ A2. In contrast to that observed for PLBs at five years after LT, the incidence of scores of ≥ A2 or ≥ F2 was 20.0% (11 cases), and all patients had an absolute score of ≥ F2. In all cases, the dose of immunosuppressants was increased after the PLB, and all ten patients who underwent a follow-up liver biopsy improved to scores of ≤ A1 or F1. CONCLUSION: PLB at two years after LT is an unnecessary examination, because the serum ALT level reflects portal inflammation. In addition, immunosuppressive therapy should be modulated to maintain the ALT concentration at a level less than 20 IU/L. PLB at five years is an excellent examination for the detection of early reversible graft fibrosis because no serum markers reflect this finding.

Some studies have found that gender mismatch between donors and recipients are related to poor graft prognosis after liver transplantation. However, few studies have investigated the impact of gender mismatch on acute cellular rejection (ACR) in pediatric living donor liver transplantation (LDLT). This retrospective study investigated the clinical significance of these factors in ACR after pediatric LDLT. Between November 2001 and February 2012, 114 LDLTs were performed for recipients with biliary atresia (BA) using parental grafts. We performed univariate and multivariate analyses to identify the factors associated with ACR. The donor-recipient classifications included mother donor to daughter recipient (MD; n = 43), mother to son (n = 18), father to daughter (FD; n = 33), and father to son (n = 20) groups. The overall incidence rate of ACR in the recipients was 36.8%. Multivariate analysis showed that gender mismatch alone was an independent risk factor for ACR (P = 0.012). The FD group had a higher incidence of ACR than the MD group (P = 0.002). In LDLT, paternal grafts with gender mismatch were associated with a higher increased incidence of ACR than maternal grafts with gender match. Our findings support the possibility that maternal antigens may have an important clinical impact on graft tolerance in LDLT for patients with BA.