Liver transplantation as an alternative for the treatment of perihilar cholangiocarcinoma: A critical review.

BACKGROUND: Perihilar cholangiocarcinoma (phCCC) is a dismal malignancy. There is no consensus regarding the best treatment for patients with unresectable phCCC. The present review aimed to gather the current pieces of evidence for liver transplantation and liver resection as a treatment for phCCC and to build better guidance for clinical practice. DATA SOURCES: The search was conducted in PubMed, Embase, Cochrane, and LILACS. The related references were searched manually. Inclusion criteria were: reports in English or Portuguese literature that a) patients with confirmed diagnosis of phCCC; b) patients treated with a curative intent; c) patients with the outcomes of liver resection and liver transplantation. Case reports, reviews, letters, editorials, conference abstracts and papers with full-text unavailability were excluded from the analysis. RESULTS: Most of the current literature is based on observational retrospective studies with low grades of evidence. Liver resection has better long-term outcomes than systemic chemotherapy or palliation therapy and liver transplantation is a good alternative for selected patients with unresectable phCCC. All candidates for resection or transplantation should be medically fit and free of intrahepatic or extrahepatic diseases. As a general rule, patients presenting with a tumor having a longitudinal size > 3 cm or extending below the cystic duct, lymph node disease, confirmed extrahepatic dissemination; intraoperatively diagnosed metastatic disease; a history of other malignancies within the last five years, and did not complete chemoradiation regimen and were medically unfit should not be considered for transplantation. Some of these criteria should be individually assessed. Liver transplantation or resection should only be considered in highly experienced hepatobiliary centers, and any decision-making must be based on a multidisciplinary evaluation. CONCLUSIONS: phCCC is a complex condition with high morbidity. Surgical therapies, including hepatectomy and liver transplantation, are the best option for better long-term disease-free survival.

Liver transplant recipients infected with SARS-CoV-2 in the early postoperative period: Lessons from a single center in the epicenter of the pandemic.

The impact of coronavirus disease-19 (COVID-19) in liver recipients remains largely unknown. Most data derive from small retrospective series of patients transplanted years ago. We aimed to report a single-center case series of five consecutive patients in the early postoperative period of deceased-donor liver transplantation who developed nosocomial COVID-19. Two patients presented important respiratory discomfort and eventually died. One was 69 years old and had severe coronary disease. She rapidly worsened after COVID-19 diagnosis on 9th postoperative day. The other was 67 years old with non-alcoholic steatohepatitis, who experienced prolonged postoperative course, complicated with cytomegalovirus infection and kidney failure. He was diagnosed on 36th postoperative day and remained on mechanical ventilation for 20 days, ultimately succumbing of secondary bacterial infection. The third, fourth, and fifth patients were diagnosed on 10th, 11th, and 18th postoperative day, respectively, and presented satisfactory clinical evolution. These last two patients were severely immunosuppressed, since one underwent steroid bolus for acute cellular rejection and another also used anti-thymocyte globulin for treating steroid-resistant rejection. Our novel experience highlights that COVID-19 may negatively impact the postoperative course, especially in elder and obese patients with comorbidities, and draws attention to COVID-19 nosocomial spread in the early postoperative period.

The role of living donor liver transplantation in treating intrahepatic cholangiocarcinoma.

Introduction: Intrahepatic cholangiocarcinoma (iCC) is the liver's second most common neoplasm. Until now, surgery is the only curative option, but only 35% of the cases are considered resectable at the diagnosis, with a post-resection survival of around 30%. Advancements in surgical techniques and perioperative care related to liver transplantation (LT) have facilitated the expansion of indications for hepatic neoplasms. Method: This study is a comprehensive review of the global experience in living donor LT (LDLT) for treating iCC and describes our first case of LDLT for an unresectable iCC. Results: While exploring LT for intrahepatic cholangiocarcinoma dates to the 1990s, the initial outcomes were discouraging, marked by poor survival and high recurrence rates. Nevertheless, contemporary perspectives underscore a reinvigorated emphasis on extending the frontiers of LT indications within the context of the "oncologic era." The insights gleaned from examining explants, wherein incidental iCC was categorized as hepatocellular carcinoma in the preoperative period, have demonstrated comparable survival rates to small hepatocellular carcinoma. These findings substantiate the potential viability of LT as a curative alternative for iCC. Another investigated scenario pertains to "unresectable tumors with favorable biological behavior," LT presents a theoretical advantage by providing free margins without the concern of a small future liver remnant. The constraint of organ shortage persists, particularly in nations with low donation rates. LDLT emerges as a viable and secure alternative for treating iCC. Conclusion: LDLT is an excellent option for augmenting the graft pool, particularly in carefully selected patients.

Islet transplantation: overcoming the organ shortage.

BACKGROUND: Type 1 diabetes mellitus (T1D) is a condition resulting from autoimmune destruction of pancreatic ß cells, leading patients to require lifelong insulin therapy, which, most often, does not avoid the most common complications of this disease. Transplantation of isolated pancreatic islets from heart-beating organ donors is a promising alternative treatment for T1D, however, this approach is severely limited by the shortage of pancreata maintained under adequate conditions. METHODS: In order to analyze whether and how this problem could be overcome, we undertook a retrospective study from January 2007 to January 2010, evaluating the profile of brain-dead human pancreas donors offered to our Cell and Molecular Therapy NUCEL Center ( www.usp.br/nucel ) and the basis for organ refusal. RESULTS: During this time period, 558 pancreata were offered by the São Paulo State Transplantation Central, 512 of which were refused and 46 were accepted for islet isolation and transplantation. Due to the elevated number of refused organs, we decided to analyze the main reasons for refusal in order to evaluate the possibility of improving the organ acceptance rate. The data indicate that hyperglycemia, technical issues, age, positive serology and hyperamylasemia are the top five main causes for declination of a pancreas offer. CONCLUSIONS: This study underlines the main reasons to decline a pancreas offer in Sao Paulo-Brazil and provides some guidance to ameliorate the rate of eligible pancreas donors, aiming at improving the islet isolation and transplantation outcome. TRIAL REGISTRATION: Protocol CAPPesq number 0742/02/CONEP 9230.

Model for establishing a new liver transplantation center through mentorship from a university with transplantation expertise.

BACKGROUND: Setting up new liver transplant (LT) centers is essential for countries with organ shortages. However, good outcomes require experience, because LT learning depends on a high number of surgeries. This study aims to describe how a new center was set up from a partnership between the new center and an experienced one. The step-by-step preparation process, the time needed and the results of the new center are depicted. MATERIAL AND METHODS: The mentoring process lasted 40 months, in which half of the 52 patients included on the transplant list received LT. After the mentorship, a 22-month period was also analyzed, in which 46 new patients were added to the waiting list and nine were operated on. RESULTS: The 30-day survival rates during (92.3%) and after (66.7%) the partnership were similar to the other LT centers in the same region, as well as the rates of longer periods. The waiting time on the LT list, the characteristics of the donors and the ischemia times did not differ during or after the mentorship. CONCLUSION: The partnership between universities is a suitable way to set up LT centers, achieving good results for the institutions and the patients involved.

Endoscopic features in a model of multivisceral xenotransplantation.

INTRODUCTION: Xenotransplantation and multivisceral transplantation are advanced therapeutic methods that still require a scientific basis. There are no experimental models of multivisceral transplantation available, particularly not the monitoring by endoscopy. Here, we describe the endoscopic features in a model of multivisceral xenotransplantation. METHODS: The distal esophagus, stomach, intestine, colon, liver, pancreas, and the kidneys with a common vascular pedicle were harvested from rabbits and implanted in swine (group I, n = 9) or in rabbits (group II, n = 4). Endoscopy was performed in the stomach, jejunum, and ascending colon at four consecutive time points (immediate after surgery and 10, 90, and 180 min after reperfusion). Lesions were macroscopically graded as mild, moderate, and severe. Biopsies were taken following sacrifice at 180 min after reperfusion. RESULTS: In group I, the stomach, jejunum, and colon manifested a progression of lesions with predominance of mild lesions after 10 min, mild to moderate lesions after 90 min, and moderate to severe lesions after 180 min. In animals from group II, endoscopy showed normal features at all time points after reperfusion. Histopathologic analysis confirmed the diagnosis of hyperacute rejection in group I. Grafts from group II animals presented normal or mild ischemic/reperfusion injury. CONCLUSION: All animals subjected to multivisceral xenotransplantation showed a progression of endoscopic lesions with time after transplantation, while animals subjected to allotransplantation showed no aberrations in endoscopy. We conclude that endoscopy is a useful tool in the assessment of hyperacute rejection of a xenograft.

Experimental multivisceral xenotransplantation.

BACKGROUND: Organ shortage impairs the proposition of multivisceral transplantation to treat multiple organ failure. Interspecies (xeno) transplantation is a valid solution for organ shortage; however, suitable models of this advance are lacking. We describe an effective model of multivisceral xenotransplantation to study hyperacute rejection. METHODS: Under general anesthesia, we in block recovered the distal esophagus, stomach, small bowel, colon, liver, pancreas, spleen, and kidneys from donors and implanted heterotopically in the lower abdomen of recipients. Animals were divided into four groups: I-canine donor, swine recipient (n = 6); II - swine donor, canine recipient (n = 5); III-canine donor, canine recipient (n = 4); and IV-swine donor, swine recipient (n = 5). Groups I and II comprised experimental (xenotransplantation) and III and IV control groups (allotransplantation). During the experiment, we appraised recipient evolution and graft modification by sequential biopsy up to 3 h. At this time, we killed animals for autopsy (experimental end point). RESULTS: We accomplished all experiments successfully. Every grafts attained customary appearance and convenient urine output immediately after unclamp. Around 15 min after reperfusion, xenografts achieved signs of progressive hyperacute rejection and absence of urine output. At the end of experiments we observed moderate to severe hyperacute rejection at small bowel, colon, mesenteric lymph node, liver, spleen, pancreas, and kidney, while stomach and esophagus achieved mild lesions. In contrast, allograft achieved normal or minimum ischemia/reperfusion injury and constant urine output. CONCLUSION: The present procedure assembles a simple and effective model to study multivisceral xenotransplantation and may ultimately spread researches toward hyperacute rejection.

Arterial Pseudoaneurysm Associated with Pancreas and Kidney Transplantation: A Case Report.

BACKGROUND Pseudoaneurysm is a rare vascular complication in pancreas transplantation. This complication develops from a disruption of the arterial continuity, usually related to trauma, infection, vasculitis, or complications in vascular procedures. CASE REPORT A 43-year-old man underwent simultaneous pancreas and kidney transplantation for end-stage renal disease. He subsequently developed acute pancreatitis and acute kidney cellular rejection as late complications, thus returning to hemodialysis. A new, uneventful kidney transplantectomy and living donor kidney transplant was performed. One year after the last transplant, the patient presented with moderate abdominal pain, fever, and a pulsatile tumor located in the right iliac fossa. A pseudoaneurysm located in the pancreatic Y graft was observed. The patient was treated using an endovascular and surgical approach. CONCLUSIONS A combined procedure using an endovascular and surgical approach promoted a good vascular control with a lower risk of bleeding in a rare case of pseudoaneurysm in a transplant patient.

Orthotopic small intestine transplantation in dogs with systemic graft drainage.

BACKGROUND: Small intestine transplantation has been accepted worldwide to treat complex cases of intestinal failure. Canine intestinal transplantation model is important in training the surgical technique and to study the complications of this procedure. Systemic graft venous drainage is frequently performed in clinic, although the consequences of this partial meso-caval shunt have not been studied in detail. AIM: To describe the surgical technique and clinical outcome of a canine intestinal transplantation model using mesenteric-caval graft drainage. METHOD: Adult mongrel dogs from University of São Paulo Animal Facility, São Paulo, SP, Brazil, were used as donors and recipients in ten consecutives orthotopic intestinal transplantation with mesenteric-caval venous drainage. Clinical examination and body weight measurement were performed daily in all animals. Necropsy was performed in animals presenting moribund state (lethargic posture, diarrhea and loss of over 35% of body weight) to determine cause of death and histological changes. RESULTS: Three recipients died before day 2 from technical complications and were excluded from the experiment. The remaining seven animals developed signs of graft rejection with onset on days 3-4 and died or were sacrificed presenting severe graft rejection between days 7-9. Necropsy and histology of the graft confirmed the diagnosis of severe acute cellular rejection. CONCLUSION: Small intestine transplantation with systemic drainage in dogs courses with analogous and lethal outcome between postoperative day 7 to 9 due to strong graft rejection. This model serves as an excellent pre-clinical model to study the main complications related to this transplantation.

Adoption of MELD score increases the number of liver transplant.

BACKGROUND: Liver transplantation is performed at large transplant centers worldwide as a therapeutic intervention for patients with end-stage liver diseases. AIM: To analyze the outcomes and incidence of liver transplantation performed at the University of São Paulo and to compare those with the State of São Paulo before and after adoption of the Model for End-Stage Liver Disease (MELD) score. METHOD: Evaluation of the number of liver transplantations before and after adoption of the MELD score. Mean values and standard deviations were used to analyze normally distributed variables. The incidence results were compared with those of the State of São Paulo. RESULTS: There was a high prevalence of male patients, with a predominance of middle-aged. The main indication for liver transplantation was hepatitis C cirrhosis. The mean and median survival rates and overall survival over ten and five years were similar between the groups (p>0.05). The MELD score increased over the course of the study period for patients who underwent liver transplantation (p>0.05). There were an increased number of liver transplants after adoption of the MELD score at this institution and in the State of São Paulo (p<0.001). CONCLUSION: The adoption of the MELD score led to increase the number of liver transplants performed in São Paulo.

Hypoxia among patients on the liver-transplant waiting list.

BACKGROUND: Hepatopulmonary syndrome is formed by a triad of liver disease, intrapulmonary vascular dilatation and changes in blood gases. This condition is present in 4-32% of patients with cirrhosis. AIM: To analyze the blood gas changes data of patients in liver-transplant waiting list. METHOD: Clinical data of 279 patients in liver transplantation waiting list in May 2013 were studied. Overall patient was analyzed by the demographic aspects, laboratorial and image findings on exams that determine lung disease (hypoxemia) in these cirrhotic patients. The mean values and standard deviations were used to examine normally distributed variables. RESULTS: There was a high prevalence of male patients (68%); the mean age was 51(± 5,89) years, and the predominant reason for listing was hepatitis C cirrhosis. The MELD score mean was 16 ± 5,89, without prioritization or special situation. The most common blood type was O in 129 cases (46%) and the mean of body max index was 25,94 ± 4,58. Regarding arterial blood gas tests was observed 214 patients with PaO2 <90 mmHg, 80 with PaO2 <80 mmHg and 39 with PaO2 <50 mmHg. In relation to O2 saturation, 50 patients had <90%, 33 <80% and 10 <50%. CONCLUSION: Was observed a high rate of hypoxemia in patients on waiting list liver transplant. Due to the high severity and morbidity, is suggested better monitoring and therapeutic support to hypoxemic patients on liver transplant waiting list.

Artery reconstruction in liver transplantation: the best reconstruction of right hepatic artery variation.

INTRODUCTION: Variations on the anatomy of the hepatic artery are common, with incidence of 20-50%. In liver transplantation, back-table reconstruction is often necessary for an easier and prompt arterial anastomosis and so, the use of arterial patches has been related to lower the incidence of complications. However, when a right hepatic artery variation from the superior mesenteric artery is present, the reconstruction occasionally produces twisting and flow problems. METHODS: Is described a surgical alternative for right hepatic artery variation reconstruction using a Carrel-patch from the superior mesenteric artery. The patch is anastomosed with the splenic artery stump to allow vertical orientation and improve blood flow. RESULTS: Among 120 liver transplants, four consecutive cases of right hepatic artery variation were reconstructed using this technique. All of them showed good flow and patency in postoperative period. CONCLUSION: The proposed technique proved to be an interesting alternative for the reconstruction of right hepatic artery variation in liver transplantation.

Portal vein thrombosis in liver transplantation.

BACKGROUND: Portal vein thrombosis was considered a contraindication for liver transplantation in the past because of the high morbidity and mortality rates. Many advances made the results better. AIM: Review the advances and surgical strategies for liver transplantation in presence of portal vein thrombosis. METHOD: Survey of publications in Medline, Scielo and Lilacs databases. Headings crossed: portal vein thrombosis, liver transplantation, vascular complications, jump graft, graft failure, multivisceral transplant. Data analyzed were epidemiology, risk factors, classification, diagnosis, surgical strategies and outcomes. CONCLUSION: Portal vein thrombosis is not a contraindication for liver transplantation anymore. There are many strategies to perform the liver transplantation in this condition, depending on portal vein thrombosis grade. Regardless higher morbidity and re-trhombosis rates, the outcomes of liver transplantation in portal vein thrombosis are similar to series without portal vein thrombosis.

A mathematical model for shortening waiting time in pancreas-kidney transplantation.

AIM: To simulate a hypothetical increase of 50% in the number of pancreas-kidney (PK) transplantations using less-than-ideal donors by a mathematical model. METHODS: We projected the size of the waiting list by taking into account the incidence of new patients per year, the number of PK transplantations carried out in the year and the number of patients who died on the waiting list or were removed from the list for other reasons. These variables were treated using a model developed elsewhere. RESULTS: We found that the waiting list demand will meet the number of PK transplantation by the year 2022. CONCLUSION: In future years, it is perfectly possible to minimize the waiting list time for pancreas transplantation through expansion of the donor pool using less-than-ideal donors.

Adoption of MELD score increases the number of liver transplant / Adoção do escore MELD aumentou número de transplantes de fígado

BACKGROUND: Liver transplantation is performed at large transplant centers worldwide as a therapeutic intervention for patients with end-stage liver diseases. AIM: To analyze the outcomes and incidence of liver transplantation performed at the University of São Paulo and to compare those with the State of São Paulo before and after adoption of the Model for End-Stage Liver Disease (MELD) score. METHOD: Evaluation of the number of liver transplantations before and after adoption of the MELD score. Mean values and standard deviations were used to analyze normally distributed variables. The incidence results were compared with those of the State of São Paulo. RESULTS: There was a high prevalence of male patients, with a predominance of middle-aged. The main indication for liver transplantation was hepatitis C cirrhosis. The mean and median survival rates and overall survival over ten and five years were similar between the groups (p>0.05). The MELD score increased over the course of the study period for patients who underwent liver transplantation (p>0.05). There were an increased number of liver transplants after adoption of the MELD score at this institution and in the State of São Paulo (p<0.001). CONCLUSION: The adoption of the MELD score led to increase the number of liver transplants performed in São Paulo. .

RACIONAL: O transplante de fígado é realizado em grandes centros de transplante em todo o mundo como intervenção terapêutica para pacientes com doenças do fígado em fase terminal. OBJETIVO: Analisar os resultados e incidência de transplante de fígado realizado na Universidade de São Paulo e comparar com a do Estado de São Paulo antes e depois da adoção do Modelo para Doença Hepática Estágio Terminal (MELD). MÉTODO: Avaliação do número de transplantes de fígado antes e depois da adoção do escore MELD. Os valores médios e desvios-padrão foram utilizados para analisar variáveis ​​normalmente distribuídas. Os resultados de incidência foram comparados com os do Estado de São Paulo. RESULTADOS: Houve alta prevalência de homens, com predomínio na meia-idade. A principal indicação para o transplante de fígado foi cirrose por hepatite C. A média e as taxas de sobrevivência mediana e sobrevida global em dez e cinco anos, foram semelhantes entre os grupos (p>0,05). A pontuação MELD aumentou ao longo do período de estudo para os pacientes que se submeteram ao transplante de fígado (p>0,05). Houve aumento do número de transplantes de fígado após a adoção do escore MELD na Universidade de São Paulo e no Estado de São Paulo (p<0,001). CONCLUSÃO: A adoção da pontuação MELD levou ao aumento do número de transplantes de fígado realizados em São Paulo. .

Hypoxia among patients on the liver-transplant waiting list / Hipoxia entre os pacientes na lista de espera para transplante de figado

Background: Hepatopulmonary syndrome is formed by a triad of liver disease, intrapulmonary vascular dilatation and changes in blood gases. This condition is present in 4-32% of patients with cirrhosis. Aim : To analyze the blood gas changes data of patients in liver-transplant waiting list. Method: Clinical data of 279 patients in liver transplantation waiting list in May 2013 were studied. Overall patient was analyzed by the demographic aspects, laboratorial and image findings on exams that determine lung disease (hypoxemia) in these cirrhotic patients. The mean values and standard deviations were used to examine normally distributed variables. Results: There was a high prevalence of male patients (68%); the mean age was 51(±5,89) years, and the predominant reason for listing was hepatitis C cirrhosis. The MELD score mean was 16±5,89, without prioritization or special situation. The most common blood type was O in 129 cases (46%) and the mean of body max index was 25,94±4,58. Regarding arterial blood gas tests was observed 214 patients with PaO2 <90 mmHg, 80 with PaO2 <80 mmHg and 39 with PaO2 <50 mmHg. In relation to O2 saturation, 50 patients had <90%, 33 <80% and 10 <50%. Conclusion: Was observed a high rate of hypoxemia in patients on waiting list liver transplant. Due to the high severity and morbidity, is suggested better monitoring and therapeutic support to hypoxemic patients on liver transplant waiting list. .

Racional: A síndrome hepatopulmonar é formada por tríade clínica com doença do fígado, dilatação vascular intrapulmonar e alterações nos gases sanguíneos. Esta condição está presente em 4-32% dos pacientes com cirrose. Objetivo : Analisar as alterações gasométricas nos pacientes em lista de espera de transplante de fígado. Método: Foram estudados dados clínicos de 279 pacientes na lista de espera para transplante hepático em maio de 2013. Foram analisados aspectos demográficos, gasometria arterial e achados de imagem que determinam a doença pulmonar (hipoxemia) nestes pacientes cirróticos. Os valores médios e desvios-padrão foram utilizados para examinar as variáveis ​​normalmente distribuídas. Resultados: Houve alta prevalência de homens (68%); a idade média foi de 51 (±5,89) anos; e a razão predominante para listar para o transplante foi cirrose pelo vírus C. O MELD médio foi de 16±5,89, sem priorização ou situação especial. O tipo de sangue mais comum foi O, 129 casos (46%) e a média do índice de massa corporal foi 25,94±4,58. Com relação aos exames de gasometria arterial, observou-se 214 pacientes com PaO2 <90 mmHg, 80 com PaO2 <80 mmHg e 39 com PaO2 <50 mmHg, e em relação à saturação de O2, 50 pacientes <90%, 33 pacientes <80% e 10 pacientes <50%. Conclusão: Observou-se alta taxa de hipoxemia nos pacientes em lista de transplante de fígado; devido à elevada gravidade e morbidade, sugere-se melhor seguimento e suporte terapêutico aos doentes hipoxêmicos na lista de espera para o transplante de fígado. .

Reconstrução arterial no transplante hepático: a melhor reconstrução para variação da artéria hepática direita / Artery reconstruction in liver transplantation: the best reconstruction of right hepatic artery variation

INTRODUÇÃO: Variações na anatomia da artéria hepática são comuns, com incidência de 20-50%. No transplante hepático, reconstruções durante a operção de bandeja são frequentemente necessárias para proporcionar anastomoses arteriais adequadas. O uso de "patch" é frequente, visando reduzir a incidência de complicações. Entretanto, quando está presente a variação da artéria hepática direita, ramo da artéria mesentérica superior, a reconstrução ocasionalmente produz torções e problemas de fluxo. MÉTODOS: Descreve-se uma técnica cirúrgica alternativa para reconstrução da variação da artéria hepática direita usando um "patch de Carrel" da artéria mesentérica superior. O "patch" é anastomosado no coto da artéria esplênica permitindo orientação vertical e bom fluxo sanguíneo. RESULTADOS: Entre 120 transplantes hepáticos, quatro casos consecutivos de variação da artéria hepática direita foram reconstruídas utilizando essa técnica. Todos eles apresentaram patência e bom fluxo no pós-operatório. CONCLUSÃO: A técnica proposta mostra-se interessante método alternativo para reconstrução da variação da artéria hepática direita no transplante hepático.

INTRODUCTION: Variations on the anatomy of the hepatic artery are common, with incidence of 20-50%. In liver transplantation, back-table reconstruction is often necessary for an easier and prompt arterial anastomosis and so, the use of arterial patches has been related to lower the incidence of complications. However, when a right hepatic artery variation from the superior mesenteric artery is present, the reconstruction occasionally produces twisting and flow problems. METHODS: Is described a surgical alternative for right hepatic artery variation reconstruction using a Carrel-patch from the superior mesenteric artery. The patch is anastomosed with the splenic artery stump to allow vertical orientation and improve blood flow. RESULTS: Among 120 liver transplants, four consecutive cases of right hepatic artery variation were reconstructed using this technique. All of them showed good flow and patency in postoperative period. CONCLUSION: The proposed technique proved to be an interesting alternative for the reconstruction of right hepatic artery variation in liver transplantation.