Analysis of risk factors following pediatric liver transplantation

Microvascular Hepatic Artery Anastomosis in Pediatric Living Donor Liver Transplantation: 73 Consecutive Cases Performed by a Single Surgeon

BACKGROUND

Living donor liver transplantation is an important strategy of procuring segmental liver allografts for pediatric patients with liver failure, as suitably sized whole donor organs are scarce. The early pediatric living donor liver transplantation experience was associated with high rates of hepatic artery thrombosis, graft loss, and mortality. Collaboration with microsurgeons for hepatic artery anastomosis in pediatric living donor liver transplantation has decreased rates of arterial complications; however, reported outcomes are limited.

METHODS

A 14-year retrospective review was undertaken of children at the authors' institution who underwent living donor liver transplantation with hepatic artery anastomosis performed by a single microsurgeon using an operating microscope. Data were collected on demographics, cause of liver failure, graft donor, vessel caliber, vessel anastomosis, arterial complications, and long-term follow-up.

RESULTS

Seventy-three children with end-stage liver failure underwent living donor liver transplantation with microvascular hepatic artery anastomosis. The commonest cause for liver failure was biliary atresia (63 percent). A total of 83 end-to-end hepatic artery anastomoses were completed using an operating microscope. Hepatic artery complications occurred in five patients, consisting of three cases of kinked anastomoses that were revised without complications and two cases of hepatic artery thrombosis (3 percent), of which one resulted in graft loss and patient death. Patient survival was 94 percent at 1 year and 90 percent at 5 years.

CONCLUSIONS

Microvascular hepatic artery anastomosis in pediatric patients undergoing living donor liver transplantation is associated with a low hepatic artery complication rate and excellent long-term liver graft function. Collaboration between microsurgeons and transplant surgeons can significantly reduce technical complications and improve patient outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Intra-operative portal hemodynamics in pediatric LDLT: Doppler ultrasound surveillance

Doppler ultrasonography is useful in monitoring intra-operative PV flow in LDLT. A retrospective cohort study included 550 pediatric recipients (<18 years) who underwent LDLT from October 2006 to August 2016 in our hospital. A total of 33 recipients (incidence 6%) were found to have insufficient intra-operative PV flow after PV reperfusion. The treatments included intra-operative stent placement (n=25), anticoagulation (n=3), thrombectomy and re-anastomosis (n=2), graft repositioning (n=1), collateral ligation (n=1), and replaced PV (n=1). The peak PV velocity, HAPSV, HARI, and HV velocity before and after the interventions were significantly improved 0(0,5.5) cm/s vs. 37.36±15.30 cm/s, 38.68±8.92 cm/s vs. 62.30±16.97 cm/s, 0.55±0.08 vs. 0.76±0.10, and 32.37±10.33 cm/s vs. 40.94±15.01 cm/s, respectively (P<.01). Insufficient PV flow and decreased HARI are two significant criteria indicating need for intra-operative PV management. Dramatic changes in the hepatic hemodynamics were detected after proper treatment. Immediate resolution of PV flow is feasible in pediatric LDLT.

Prediction of early hepatic artery thrombosis by intraoperative color Doppler ultrasound in pediatric segmental liver transplantation

Early hepatic artery thrombosis (eHAT) after transplantation is associated with a high incidence of graft failure and mortality in pediatric segmental liver transplantation (LT). The evaluation of intraoperative color Doppler ultrasound (CD-US) parameters and their sensitivity and specificity for the prediction of eHAT were important. Pediatric segmental LTs were performed in 49 consecutive patients from October 2006 to December 2010 in our hospital. A total of seven patients (14.3%) experienced eHAT (within one month) after LT. The intraoperative hepatic artery (HA) diameter (p = 0.026), hepatic arterial peak systolic velocity (HAPSV) (p = 0.006), and hepatic artery resistance index (HARI) (p = 0.000) had significant difference between eHAT group and non-eHAT group. Taking a HA diameter <2 mm, a HAPSV of <40 cm/s and a HARI of <0.6 as threshold to predict eHAT, the sensitivity and specificity were 85.7%, 85.7%, 85.7%, and 61.9%, 76.2%, 88.1%, respectively. A HARI of <0.6 was shown to be the most sensitive and specific single parameter for predicting eHAT.

Revisited impact of recipient age on the outcome of living donor liver transplantation for biliary atresia in the recent "transplantation era" in Japan

To re-evaluate the impact of recipient age on the outcome of LDLT for BA in an era in which LDLT is the established treatment for BA in Japan. Thirty-one patients with BA who underwent LDLT were divided into four groups regarding the age at LDLT: infants <1 yr old (group A; n = 14); young children 1 to 6 yr old (group B; n = 8); school children 6 to 15 yr old (group B; n = 5); and adults > or =15 yr old (group D; n = 4). Pre-, peri-, and postoperative factors were compared among the four groups. There was no significant difference in number of the previous laparotomy among the groups. Cholestasis was the dominant indication in group A. PELD score in group B was lower than that in the other groups, and blood loss in group B was significantly less than in groups A and D. Ratio of the graft weight to the recipient's body weight (GRWR) in group A was significantly higher than in other groups. Duration of operation in group D was lower than in groups A and B, but there was no significant difference in the length of postoperative hospital stay and graft survival. Although the case volume was not big, the age of the recipient did not have any significant impact on the outcome of LDLT in our series.

Remote ischemic preconditioning: a novel protective method from ischemia reperfusion injury--a review

BACKGROUND

Restoration of blood supply to an organ after a critical period of ischemia results in parenchymal injury and dysfunction of the organ referred to as reperfusion injury. Ischemia reperfusion injury is often seen in organ transplants, major organ resections and in shock. Ischemic preconditioning (IPC) is an adaptational response of briefly ischemic tissues which serves to protect against subsequent prolonged ischemic insults and reperfusion injury. Ischemic preconditioning can be mechanical or pharmacological. Direct mechanical preconditioning in which the target organ is exposed to brief ischemia prior to prolonged ischemia has the benefit of reducing ischemia-reperfusion injury (IRI) but its main disadvantage is trauma to major vessels and stress to the target organ. Remote (inter organ) preconditioning is a recent observation in which brief ischemia of one organ has been shown to confer protection on distant organs without direct stress to the organ.

AIM

To discuss the evidence for remote IPC (RIPC), underlying mechanisms and possible clinical applications of RIPC. METHODS OF SEARCH: A Pubmed search with the keywords "ischemic preconditioning," "remote preconditioning," "remote ischemic preconditioning," and "ischemia reperfusion" was done. All articles on remote preconditioning up to September 2006 have been reviewed. Relevant reference articles from within these have been selected for further discussion.

RESULTS

Experimental studies have demonstrated that the heart, liver, lung, intestine, brain, kidney and limbs are capable of producing remote preconditioning when subjected to brief IR. Remote intra-organ preconditioning was first described in the heart where brief ischemia in one territory led to protection in other areas. Translation of RIPC to clinical application has been demonstrated by the use of brief forearm ischemia in preconditioning the heart prior to coronary bypass and in reducing endothelial dysfunction of the contra lateral limb. Recently protection of the heart has been demonstrated by remote hind limb preconditioning in children who underwent surgery on cardiopulmonary bypass for congenital heart disease. The RIPC stimulus presumably induces release of biochemical messengers which act either by the bloodstream or by the neurogenic pathway resulting in reduced oxidative stress and preservation of mitochondrial function. Studies have demonstrated endothelial NO, Free radicals, Kinases, Opioids, Catecholamines and K(ATP) channels as the candidate mechanism in remote preconditioning. Experiments have shown suppression of proinflammatory genes, expression of antioxidant genes and modulation of gene expression by RIPC as a novel method of IRI injury prevention.

CONCLUSION

There is strong evidence to support RIPC. The underlying mechanisms and pathways need further clarification. The effective use of RIPC needs to be investigated in clinical settings.

Predictors of clinical outcome in children undergoing orthotopic liver transplantation for acute and chronic liver disease

The current United Network for Organ Sharing (UNOS) policy is to allocate liver grafts to pediatric patients with chronic liver disease based on the pediatric end-stage liver disease (PELD) scoring system, while children with fulminant hepatic failure may be urgently listed as Status 1a. The objective of this study was to identify pre-transplant variables that influence patient and graft survival in those children undergoing LTx (liver transplantion) for FHF (fulminant hepatic failure) compared to those patients transplanted for extrahepatic biliary atresia (EHBA), a chronic form of liver disease. The UNOS Liver Transplant Registry was examined for pediatric liver transplants performed for FHF and EHBA from 1987 to 2002. Variables that influenced patient and graft survival were assessed using univariate and multivariate analysis. Kaplan-Meier analysis of FHF and EHBA groups revealed that 5 year patient and graft survival were both significantly worse (P < 0.0001) in those patients who underwent transplantation for FHF. Multivariate analysis of 29 variables subsequently revealed distinct sets of factors that influenced patient and graft survival for both FHF and EHBA. These results confirm that separate prioritizing systems for LTx are needed for children with chronic liver disease and FHF; additionally, our findings illustrate that there are unique sets of variables which predict survival following LTx for these two groups.

Use of donor aorta for arterial reconstruction in paediatric liver and multivisceral transplantation

BACKGROUND

Arterial reconstruction remains the most important technical issue in paediatric transplantation. The arteries of paediatric donors as well as recipients are small and friable. The aim of this study was to assess the use of the donor aorta as a conduit for arterial reconstruction in paediatric liver and multivisceral transplantation.

METHODS

Between June 1994 and January 2002, 284 paediatric transplants, including 197 cadaveric liver and multivisceral transplants, were performed in children at this centre. Of these, 41 (20.8 per cent), including nine cadaveric liver transplants and 32 multivisceral transplants, were revascularized by donor aortic reconstruction. Patient demographics, types of donor arterial reconstruction, technical complications and incidence of hepatic artery thrombosis were reviewed.

RESULTS

None of the 41 donor aortic reconstructions used in revascularization of paediatric liver and multivisceral transplants thrombosed. There were no bleeding complications and no pseudoaneurysms developed.

CONCLUSION

Arterial reconstruction using donor aorta is a useful option with a low incidence of thrombosis in paediatric transplantation.

Treatment of Crigler-Najjar type 1 disease: relevance of early liver transplantation

BACKGROUND

Crigler-Najjar syndrome type 1 (CNS1) is characterized by severe unconjugated hyperbilirubinemia from birth, caused by total failure of UDP-glucuronyltransferase activity. Only orthotopic liver transplantation (OLT) offers the prospect of cure. However, because the onset of neurologic deficits is unpredictable, timing of OLT remains difficult.

METHODS

In our transplant center, 3 patients underwent early OLT for CNS1. Two of them (7 yr, 12 yr) showed mild to moderate neurologic deficits only few weeks before OLT, another patient (4 yr) had no signs of bilirubin encephalopathy. All patients required extensive phototherapy to control bilirubin levels. Thus, OLT was performed shortly after the onset of neurologic symptoms or as a prophylactic procedure, respectively.

RESULTS

OLT was uneventful in all recipients. One of the symptomatic patients (7 yr) completely recovered from neurologic deficits at 36 months on OLT, whereas the other patient (12 yr) significantly improved symptoms at 27 months of OLT. These patients, including the 4-year-old boy, attend school at appropriate grades now.

CONCLUSIONS

Irreversible brain damage (kernicterus) may occur in the course of CNS1 disease. Because no alternative treatment options are available at this time, OLT should be performed as a preventive procedure to counteract severe CNS-related complications.

Hepatic artery reconstruction in living-donor liver transplantation: a review of its techniques and complications

BACKGROUND

Hepatic arterial reconstruction is one of the most difficult procedures in living-donor liver transplantation (LDLT) because the artery used is generally small in diameter and has a short stalk. If hepatic artery thrombosis (HAT) occurs, the recipient clinical course will be unstable. The introduction of microvascular hepatic arterial reconstruction has significantly decreased the incidence of HAT.

METHODS

Fifty-two cases of LDLT were performed from October 1995 to May 2001 in our institution. Hepatic arterial reconstruction was performed under microscopic guidance.

RESULTS

HATs were recognized in 2 cases (3.8%), both of which needed reoperation.

CONCLUSIONS

Surgeons who perform hepatic arterial reconstruction in LDLT should be highly trained in microvascular techniques to decrease the incidence of HAT. This commentary reviews the surgical techniques of hepatic arterial reconstruction and possible complications that may arise in a reconstructed hepatic artery.