Naoya Yamada

Jichi Medical University, Totigi, Tochigi, Japan

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Publications (32)44.7 Total impact

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    ABSTRACT: Background In the field of pediatric living donor liver transplantation (LDLT), physicians soetimes must reduce the volume of left lateral segment (LLS) grafts to prevent large-for-size syndrome. There are two established methods for decreasing the size of an LLS graft: the use of a segment 2 (S2) monosegment graft or that 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 <6kg.Patients and Methods Among 225 LDLTs conducted between May 2001 and December 2012, 15 were performed in patients weighing <6kg. We selected S2 monosegment grafts and reduced-LLS grafts if the preoperative computed tomography (CT)-volumetry value of the LLS graft was >5% and 4-5% of the graft recipient weight ratio, respectively. The mean follow-up period was 3.9 ± 2.2 years.ResultsWe used LLS grafts in 7 recipients, S2 monosegment grafts in 5, reduced-S2 monosegment grafts in 2, and a reduced-LLS graft in 1. The reduction rate of S2 monosegment graft for use as an LLS graft 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 stricture in 2, and portal vein thrombosis in 1.Conclusion Our graft selection strategy based on preoperative CT-volumetry is highly useful in patients weighing <6kg. S2 monosegment grafts are effective and safe in very small infants, particularly neonates. This article is protected by copyright. All rights reserved.
    Liver Transplantation 11/2014; · 3.94 Impact Factor
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    ABSTRACT: 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.
    Pediatric Transplantation 09/2014; · 1.50 Impact Factor
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    ABSTRACT: Abstract We report a 71-year-old man who had undergone pylorus-preserving pancreatoduodenectomy (PPPD) using PPPD-IV reconstruction for cholangiocarcinoma. For 6 years thereafter, he had suffered recurrent cholangitis, and also a right liver abscess (S5/8), which required percutaneous drainage at 9 years after PPPD. At 16 years after PPPD, he had been admitted to the other hospital because of acute purulent cholangitis. Although medical treatment resolved the cholangitis, the patient was referred to our hospital because of dilatation of the intrahepatic biliary duct (B2). Peroral double-balloon enteroscopy revealed that the diameter of the hepaticojejunostomy anastomosis was 12 mm, and cholangiography detected intrahepatic stones. Lithotripsy was performed using a basket catheter. At 1 year after lithotripsy procedure, the patient is doing well. Hepatobiliary scintigraphy at 60 minutes after intravenous injection demonstrated that deposit of the tracer still remained in the upper afferent loop jejunum. Therefore, we considered that the recurrent cholangitis, liver abscess, and intrahepatic lithiasis have been caused by biliary stasis due to nonobstructive afferent loop syndrome. Biliary retention due to nonobstructive afferent loop syndrome may cause recurrent cholangitis or liver abscess after hepaticojejunostomy, and double-balloon enteroscopy and hepatobiliary scintigraphy are useful for the diagnosis of nonobstructive afferent loop syndrome.
    International surgery. 07/2014; 99(4):426-431.
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    ABSTRACT: β-D glucan in the portal vein blood is processed by the hepatic reticuloendothelial system, and therefore, it is possible that the β-D glucan kinetics of the peripheral vein blood may be useful as a biological index. In this study, the β-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. The subjects comprised 20 patients who underwent living donor liver transplantation. In the perioperative period, the β-D glucan levels were measured before liver transplantation, during surgical procedure, then on postoperative days 5, 14 and 21. The portal vein blood showed a significantly higher level of β-D glucan than the peripheral blood (p<0.001). A significant difference of β-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 β-D glucan level and the period of postoperative hospitalization (p<0.001). The patients with fungal infections (35.0%) had a significantly longer period of hospitalization (p=0.019). The β-D glucan kinetics accurately reflects the liver function and fungal infections. The β-D glucan level before liver transplantation can be used to
    Hepato-gastroenterology 07/2014; 61(133):1368-73. · 0.77 Impact Factor
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    ABSTRACT: To assessed the clinical significance of protocol liver biopsy (PLB) in pediatric liver transplantation (LT).
    World journal of gastroenterology : WJG. 06/2014; 20(21):6638-50.
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    ABSTRACT: Iron is an essential nutrient for living cells; however, an excessive accumulation of iron leads to organ damage and directly affects systemic immunity. Iron overload is clinically classified as hereditary or secondary. Most of secondary iron overload is caused by frequent blood transfusions because there is no active mechanism to excrete iron from the body. As recommended in various guidelines, chelation therapy is effective for reducing iron burden and improving organ function. There have been few reports on iron overload through blood transfusion during the perioperative period of liver transplantation. This report presents a case of iron overload due to repeated transfusions after pediatric liver transplantation managed by chelation therapy. The patient, an 11-month-old female with biliary atresia, underwent living donor liver transplantation. She revealed refractory anemia and required frequent blood transfusion. Both serum ferritin and transferrin saturation tended to increase after repeated transfusions, leading to secondary iron overload. Iron chelation therapy was started to prevent progression to organ failure and infection due to iron overload, and yielded a favorable outcome. It is crucial to consider the possibility of secondary iron overload and to achieve early detection and treatment to avoid progression to irreversible organ damage.
    Transplantation Proceedings 04/2014; 46(3):973-6. · 0.95 Impact Factor
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    ABSTRACT: Anastomotic stricture of the choledochojejunostomy is a common complication after living donor liver transplantation. Most anastomotic strictures can be treated by percutaneous transhepatic cholangiodrainage and/or double balloon endoscopy. However, in severe cases and/or in small infants, neither of these is possible. Our new technique, cholangiography accompanied by cholangioscopy, enabled successful guidewire placement and balloon dilatation in cases with severe anastomotic stricture.
    Transplantation Proceedings 04/2014; 46(3):999-1000. · 0.95 Impact Factor
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    ABSTRACT: 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.
    European Journal of Pediatric Surgery 03/2014; · 0.84 Impact Factor
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    ABSTRACT: 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 BA patients. This article is protected by copyright. All rights reserved.
    Transplant International 01/2014; · 3.16 Impact Factor
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    ABSTRACT: The development of late-onset hepatic venous outflow obstruction (LOHVOO) following pediatric living donor liver transplantation (LDLT) can lead to uncontrollable fibrotic damage in liver grafts, even long-term patency of the graft outflow is achieved with appropriate therapeutic modalities. The aim of this study was to verify our hypothesis that some immunological responses, particularly cellular and/or antibody-mediated rejection, are associated with LOHVOO, which occurs following damage to liver sinusoidal endothelial cells in zone 3 of liver grafts. One hundred and eighty-nine patients underwent LDLT between May 2001 and December 2010 at our institute. Nine patients (4.8%) were identified as having LOHVOO. The preoperative factors, operative factors and mortality, morbidity and survival rates were examined and compared between the groups with and without LOHVOO. No statistical differences were observed between the groups with regard to preoperative factors, technical factors or postoperative complications. However, FlowPRA reactivity was found to be a statistically significant risk factor for LOHVOO (P=0.006). The patients with both class I and class II reactive antibodies also had a significant risk of developing LOHVOO (P=0.03) and exhibited significantly higher retransplant rates. In conclusion, although further studies are needed to clarify this phenomenon, the pathophysiological mechanism underlying the development of LOHVOO after LDLT may be explained by immune-mediated responses that facilitate damage in zone 3 of liver grafts. This article is protected by copyright. All rights reserved.
    Transplant International 12/2013; · 3.16 Impact Factor
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    ABSTRACT: 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. 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. 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). 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.
    Journal of hepato-biliary-pancreatic sciences. 10/2013;
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    ABSTRACT: Abnormalities of liver function tests are frequently documented in patients with Kawasaki disease, but the mechanism responsible for this has not yet been established. Described herein is the case of a 1-year-10-month-old girl who underwent liver transplantation at 11 months of age. Eleven months after transplantation the patient was diagnosed with Kawasaki disease, which was associated with some portal flow reduction, and received i.v. immunoglobulin, after which fever abated with improvement of portal flow to its pre-fever level. Abnormalities of liver function tests in Kawasaki disease patients may occur as a result of inflammation of both the biliary and portal systems. There are no reports on the potential relationship between Kawasaki disease and the portal vein, and accumulation of further data is necessary to better examine this relationship.
    Pediatrics International 10/2013; 55(5):e119-22. · 0.88 Impact Factor
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    ABSTRACT: OBJECTIVES: Treatment for patients with biliary atresia is a Kasai hepatic portoenterostomy; however, the efficacy of repeat Kasai hepatic portoenterostomy is unclear. This study sought to examine the effect of a prior Kasai hepatic portoenterostomy, especially a repeat Kasai hepatic portoenterostomy, on the outcomes of living-donor liver transplant. MATERIALS AND METHODS: One hundred twenty-six of 170 children that underwent a living-donor liver transplant between May 2001, and March 2010, received a living-donor liver transplant for biliary atresia. These patients were divided into 2 groups according to the number of previous portoenterostomies: 1 (group A, n=100) or 2 or more Kasai hepatic portoenterostomies (group B, n=26). Portoenterostomy was performed twice in 24 patients in group B, 3 times in 1, and 4 times in 1. Preoperative, operative factors, mortality, morbidity, and survival rates were examined and compared between groups. RESULTS: The surgical factors such as operative time, blood loss per weight, cold ischemia time, and weight of the native liver were significantly greater in group B than they were in group A. The patient survival rates were comparable in the 2 groups (94.5% in group A and 93.3% in group B), and the difference was not statistically significant. No statistically significant difference was observed between the groups with regard to vascular complications, biliary complications, and other factors including postoperative variables. Bowel perforation requiring surgical repair was more frequent in group B than it was in group A. CONCLUSIONS: Repeat Kasai hepatic portoenterostomy might have a negative effect on patients who undergo living-donor liver transplant for biliary atresia patients with potential lethal complications such as bowel perforation. More biliary atresia patients could have a liver transplant, with improved survival and better life expectancy, if they have inadequate biliary drainage after the initial Kasai hepatic portoenterostomy.
    Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation. 03/2013;
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    ABSTRACT: There are currently 2 major therapeutic options for the treatment of hepatic artery complications: endovascular intervention and open surgery. We herein report a retrospective analysis of 14 pediatric patients with hepatic artery complications after pediatric living donor liver transplantation (LDLT) at our institution. We divided them into an open surgery group and an endovascular intervention group based on their primary treatment, and compared the results and outcomes. We then evaluated which procedure is more effective and less invasive. In the open surgery group, recurrent stenosis or spasm of the hepatic artery occurred in 3 of the 8 patients (37.5%). In the endovascular intervention group, 5 of the 6 patients were technically successfully treated by only endovascular treatment. Of the 5 successfully treated patients, 3 developed recurrent stenosis (60%). There were significant differences in the mean length of the operation for the first treatment of hepatic artery complications (open surgery, 428 minutes vs endovascular intervention, 160 minutes; P = .01) and in the mean value of the posttreatment aspartate aminotransferase (AST)/alanine aminotransferase (ALT) (open surgery > endovascular intervention; P = .04/.05). Although endovascular intervention needs to be examined in further studies to reduce the rate of relapse, it is a less invasive method for the patient and graft than open surgery.
    Transplantation Proceedings 01/2013; 45(1):323-9. · 0.95 Impact Factor
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    ABSTRACT: Fluid collection is common after living donor liver transplantation (LDLT), and can include hematomas, bilomas, abscesses, and seromas. Although accumulated fluid rarely becomes infected and usually remains localized, localized ascites can sometimes be sufficiently extensive to induce vascular complications. This report presents three such cases in pediatric patients that underwent LDLT. A 33-month-old patient showed an increase in the volume of localized ascites around the hepatic vein anastomoses together with low hepatic vein flow on postoperative day (POD) 47. An 82-month-old patient showed an increase in the volume of localized ascites around the portal vein anastomoses together with low portal vein flow on POD 71. A 63-month-old patient showed an increase in the size of a localized abscess around the hepaticojejunostomy with dilatation of all of the intrahepatic bile ducts on POD 20. These cases illustrate the need for awareness of possible vascular or biliary complications due to compressive localized ascites after LDLT.
    Surgery Today 10/2012; · 0.96 Impact Factor
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    ABSTRACT: The pediatric end-stage liver disease (PELD) score is not a direct index that reflects the degree of hepatocellular injury. Beta-D glucan (BDG) in the portal vein blood is processed by the hepatic reticuloendothelial system. It is possible that the hepatic clearance of BDG may be used as a biological index to assess the liver function. In this study, the relationship between PELD score and hepatic clearance of BDG was made clear in order to study the efficacy of measurement of the serum BDG. This study including 21 patients with biliary atresia (BA) who underwent liver transplantation (LT) was performed. The BDG was measured in the preoperative peripheral vein blood and the portal vein blood at the time of LT. The portal vein blood showed a significantly high level of BDG than the peripheral vein blood (p < 0.01). There was a significant negative correlation between the PELD score and the hepatic clearance of BDG in the 10 patients who were indicated for LT due to liver failure (p < 0.01). The serum BDG can be used as a biological index in place of liver metabolism and should be measured in BA patients as a non-invasive indicator of the degree of progression of liver failure.
    Pediatric Surgery International 08/2012; 28(10):993-6. · 1.22 Impact Factor
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    ABSTRACT: In the field of pediatric living donor liver transplantation, the indications for apheresis and dialysis, and its efficacy and safety are still a matter of debate. In this study, we performed a retrospective investigation of these aspects, and considered its roles. Between January 2008 and December 2010, 73 living donor liver transplantations were performed in our department. Twenty seven courses of apheresis and dialysis were performed for 19 of those patients (19/73; 26.0%). The indications were ABO incompatible-liver transplantation in 11 courses, fluid management in seven, acute liver failure in three, renal replacement therapy in two, endotoxin removal in two, cytokine removal in one, and liver allograft dysfunction in one. Sixteen courses of apheresis and dialysis were performed prior to liver transplantation for 14 patients. The median IgM antibody titers before and after apheresis for ABO blood type-incompatible liver transplantation was 128 and eight, respectively (P < 0.05). Eleven courses of apheresis and dialysis were performed post liver transplantation for 10 patients. The median PaO2/FiO2 ratio before and after dialysis for fluid overload was 159 and 339, respectively (P < 0.05). No bleeding or technical complications attributable to apheresis and dialysis occurred. The 1-year survival rate of the patients was 100%. Apheresis and dialysis in pediatric living donor liver transplantation are effective for antibody removal in ABO-incompatible liver transplantation, and fluid management for acute respiratory failure.
    Therapeutic apheresis and dialysis: official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy 08/2012; 16(4):368-75. · 1.53 Impact Factor
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    ABSTRACT: Posttransplant portosystemic shunts may result in severe fatty changes, portal vein complications, or graft liver failure because they reduce the effectiveness of portal perfusion through a portal steal phenomenon. However, the indications and timing of surgical and interventional treatments for posttransplant portosystemic shunts are still a matter of debate. We performed a retrospective investigation of the present state of long-term outpatients with posttransplant portosystemic shunts. This study comprised 150 outpatients who underwent liver transplantation between October 1988 and August 2006 in our department and other facilities. The diagnosis was based on the presence of any portosystemic shunts with the diameter of more than 5 mm indicated by computed tomography. A total of 16 patients (16/150, 10.7 %) were diagnosed as having posttransplant portosystemic shunt. Among them, eight patients (8/16, 50.0 %) developed portal vein complications, and 1 (1/16, 6.3 %) developed graft liver failure. The persistence of posttransplant portosystemic shunts results in portal vein complications or graft liver failure. Therefore, surgical and interventional treatment for patients with posttransplant portosystemic shunts should be performed based on the clinical and radiologic findings.
    World Journal of Surgery 06/2012; 36(10):2449-54. · 2.23 Impact Factor
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    ABSTRACT: Acute cellular rejection (ACR) is a common cause of morbidity following liver transplantation. Several reports have evaluated the predictive value of peripheral blood eosinophilia as a simple noninvasive diagnostic marker for ACR. This study examined whether the relative eosinophil counts (REC) predicted ACR in pediatric living donor liver transplantation (LDLT). One hundred three patients underwent LDLT between May 2001 and December 2007. ACR were diagnosed based on the pathological findings. The incidence of ACR was 46.6% (48/103); ACR was diagnosed an average of 13.5 days after LDLT. The average REC at 4 and 2 days before the onset ACR (n = 39) within 30 postoperative day (POD) was 4.3% and 7.3%, respectively, and 9.0% at the onset. Patients with ACR showed significantly higher levels of REC compared with those free of ACR (P = .039). REC thresholds of 10% at POD 7 displayed a sensitivity and specificity of ACR detection of 80% and 75%, respectively. Moreover, the accumulated morbidity ratio of ACR within 30 POD was significantly higher with REC >10% at POD 7 (P = .007). ACR within POD 30 should be considered when REC is >10% at POD 7 after LDLT.
    Transplantation Proceedings 06/2012; 44(5):1341-5. · 0.95 Impact Factor
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    ABSTRACT: BACKGROUND: Endotoxin (Et) in the portal vein blood is processed by the hepatic reticuloendothelial system. Thus, it is possible that the Et kinetics of the peripheral venous blood may be useful as a biological index that can be used to evaluate liver function. In this study, we measured Et using the endotoxin activity assay in peripheral venous blood during living donor liver transplantation (LDLT), to study its clinical significance. METHODS: Subjects were 17 patients who underwent LDLT. In the perioperative peripheral venous blood, was measured Et activity (EA) using the endotoxin activity assay at 1 or 2 d before LT, and then on 1, 5, 7, 14, and 21 postoperative days. RESULTS: Patients with infections had significantly higher EA levels compared with those without complications before LDLT and 14 postoperative days (P = 0.038 and 0.027, respectively). The average EA level of patients with infections and without complications before LT was 0.22 and 0.08, respectively (P = 0.038). Patients with an EA level higher than 0.20 before LDLT had a significantly longer period of hospitalization compared with those without complications (P = 0.038). CONCLUSIONS: A preoperative EA level more than 0.20 is a high risk factor for post-transplant infection and a prolonged period of hospitalization.
    Journal of Surgical Research 05/2012; · 2.02 Impact Factor