Pediatric liver transplantation: the Montreal experience

The Transition to Microsurgical Technique for Hepatic Artery Reconstruction in Pediatric Liver Transplantation

BACKGROUND

Hepatic artery thrombosis represents a potentially fatal complication following liver transplantation. Rates of hepatic artery thrombosis are significantly higher in children, with mortality reported up to 80 percent. Microsurgical anastomosis has been shown to decrease the rate of hepatic artery thrombosis and now represents the standard of care at the authors' institution. In this article, the authors present the largest study of its type directly comparing rates of hepatic artery thrombosis with and without microsurgical reconstruction of the hepatic artery.

METHODS

All pediatric patients who underwent primary orthotopic liver transplantation between 1989 and 2018 were included. Patients were divided into two cohorts: standard anastomosis with loupes, and microsurgical anastomosis under the operating microscope. The authors' primary outcome was the rate of hepatic artery thrombosis. Secondary outcomes were graft survival, patient survival, retransplantation rate, requirement for intraoperative blood products, and length of stay.

RESULTS

Two hundred thirty-one children met criteria for inclusion. One hundred eighty cases were performed with loupe magnification and 51 cases were performed under the microscope. The hepatic artery thrombosis rate was lower, but not significantly so (p = 0.114), in the microsurgical group [n = 1 (2.0 percent)] compared with the standard cohort [n = 15 (8.3 percent)]. Survival analysis revealed a significant increase in graft survival with microsurgical anastomosis (p = 0.020), but not patient survival (p = 0.196). The retransplantation rate was significantly lower with microsurgical anastomosis (p = 0.021).

CONCLUSIONS

Microsurgical anastomosis was associated with a clinically important decrease in hepatic artery thrombosis compared with standard loupe anastomosis. The graft survival rate was significantly higher in the microsurgical cohort, with a reduced retransplantation rate at 1 year. On this basis, the authors recommend microsurgical hepatic artery anastomosis in cases of pediatric liver transplantation. .

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Domino liver transplantation in maple syrup urine disease

Liver transplantation has been reported in a few cases of maple syrup urine disease (MSUD), but is controversial. Many patients with approved indications for liver transplantation die before grafts are available. A 25-yr-old man with MSUD underwent liver transplantation, and his liver was used as a domino graft for a 53-yr-old man with hepatocellular carcinoma who had low priority on the liver transplant waiting list and was unlikely to survive until routine organ procurement. Both transplants were performed as "piggy back" procedures, reconstructing the domino graft with caval segments from the cadaveric donor. Neither required veno-venous bypass. Whole body leucine oxidation was estimated by 13CO2 in breath after oral boluses of L-[1-13C]-leucine, before and after transplantation in both patients and a control subject. The surgical outcome was successful. The patient with MSUD had marked decreases in plasma branched-chain amino acids (BCAAs) and alloisoleucine (from 255 +/- 66 to 16 +/- 7 micromol/L), despite advancement of dietary protein from 6 to >40 gm/day. The domino recipient maintained near-normal levels of plasma amino acids with no detectable alloisoleucine on unrestricted diet. Leucine oxidation increased in the patient with MSUD (from 2.2 to 5.6% recovered in 4 hours) and decreased in the recipient (from 9.7 to 6.2%). Neither patient demonstrated any apparent symptoms of MSUD over more than 7 months. In conclusion, liver transplantation substantially corrects whole body BCAA metabolism in MSUD and greatly attenuates the disease. Livers from patients with MSUD may be considered as domino grafts for patients who might otherwise not survive until transplantation.

Supraceliac aortic pseudoaneurysms after liver transplantation in infants

BACKGROUND

Reconstruction of the hepatic artery in infants undergoing liver transplantation presents challenging vascular situations. Microvascular techniques ensure arterial blood flow via small caliber vessels but are insufficient when inflow is poor. In these situations, the use of allogeneic grafts to the supraceliac aorta have been advocated. The development of a pseudoaneurysm at the supraceliac aortic suture line requires urgent repair and restoration of arterial flow to the graft.

METHODS

Our study was based on case reports and review of the literature.

RESULTS

Definitive diagnosis and successful repair of supraceliac pseudoaneurysm was accomplished in two infants after transplantation.

CONCLUSION

We advocate a thoracoabdominal retroperitoneal approach, which provides safe control of the aorta and primary repair or patching of the diseased aortic segment, and also provides access for hepatic revascularization via placement of an infrarenal graft. Thrombosis of the artery and subsequent liver necrosis are indications for retransplantation.

Vascular complications after pediatric liver transplantation

From February 1986 to July 1994, 81 hepatic transplantations were performed in 73 children, with an overall patient survival rate of 83%. Forty-two patients received whole-liver grafts (WLG) and 39 had reduced-size grafts (RSG). The mean patient weight was 19.7 kg, with 29 patients weighing less than 10 kg. Seventeen vascular complications (21%) occurred in 13 children: 8 (10%) had hepatic artery thrombosis (HAT), 5 (6%) had portal vein thrombosis (PVT), 1 had both HAT and PVT (1%), and 3 (4%) had aortic conduit perforation (ACP). There was no significant difference in the incidence of HAT between RSG (5%) and WLG (14%) or between children weighing less than 10 kg (10%) and those weighing more than 10 kg (10%). The site of arterial reconstruction, end-to-end to the recipient common hepatic artery or end-to-side to the infrarenal aorta, had no significant effect on the occurrence of HAT (7% v 8%), but HAT occurred in 2 of 6 cases (33%) in which an aortic conduit was used. PVT documented in 5 cases (6%) was associated with technical complications (2), preduodenal portal vein (2), and a circulating cardiolipid antibody (1), and required thrombectomy, with no graft loss. Combined HAT and PVT was found in one patient 2 years postretransplantation for HAT. Although graft function is normal, portal hypertension persists. The aortic conduit, used in six patients, led to arterial perforation (3), HAT (2), and death (2). Of the 8 cases of HAT, 1 was diagnosed during autopsy and 7 occurred within 30 days and required retransplantation (6) or thrombectomy with rearterialization (1).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological correction of neonatal lethal hepatic dysfunction in a murine model of hereditary tyrosinaemia type I

Hereditary tyrosinaemia type I, a severe autosomal recessive metabolic disease, affects the liver and kidneys and is caused by deficiency of fumarylacetoacetate hydrolase (FAH). Mice homozygous for a FAH gene disruption have a neonatal lethal phenotype caused by liver dysfunction and do not represent an adequate model of the human disease. Here we demonstrate that treatment of affected animals with 2-(2-nitro-4-trifluoro-methylbenzyol)-1,3-cyclohexanedione abolished neonatal lethality, corrected liver function and partially normalized the altered expression pattern of hepatic mRNAs. The prolonged lifespan of affected animals resulted in a phenotype analogous to human tyrosinaemia type I including hepatocellular carcinoma. The adult FAH-/- mouse will serve as useful model for studies of the pathophysiology and treatment of hereditary tyrosinaemia type I as well as hepatic cancer.

Biliary tract complications in pediatric orthotopic liver transplantation

Biliary tract complications are reported in 15% to 30% of orthotopic liver transplantations (OLTs). Since 1986, 53 OLTs were done in 48 children with a mean age and weight of 5.3 years and 18.9 kg, respectively. Twenty-seven transplantations (51%) were reduced liver grafts (RLG) and 26 (49%) were whole liver grafts (WLG). Since 1988, 70% of transplantations have been RLG. Choledochocholedochostomy (mean weight, 25 kg) with a T-tube (CC) or choledochojejunostomy (CJ) (mean weight, 14.5 kg) were done in 24 (45%) and 29 (55%) cases, respectively. The overall mortality was 19% but none of the deaths were related to biliary problems. There were 13 biliary tract complications (24.5%) in 11 patients including 7 leaks, 5 obstructions, and 1 intrahepatic biloma. Leaks leading to bile peritonitis were managed with simple suture and drainage and were related to the T-tube (4), to the Roux-en-Y loop (2), and to the transection margin of a RLG (1). Obstruction was documented in 5 cases with none associated with hepatic artery thrombosis (HAT). Stenosis after CC reconstruction (2) required conversion to CJ. Two patients had revision of CJ because of kinking of the common bile duct after a left lateral segment graft and an anastomotic stricture 46 months after OLT. The last patient developed a vanishing bile duct syndrome 4 months posttransplant and is awaiting retransplantation. One patient had multiple episodes of cholangitis after HAT and was retransplanted. Neither the type of grafts (RLG 25.9% v WLG 23.1%) nor the type of biliary reconstruction (CC 25% v CJ 24%) influenced the rate of biliary complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Infectious complications of pediatric liver transplantation

Twenty-five pediatric orthotopic liver transplantations (OLTs) performed in 22 patients at Sainte-Justine Hospital were reviewed for infections complications. One patient died within 12 hours posttransplantation and is excluded. The patients had an average age of 6.1 years (range, 1.25 to 19 years) and an average weight of 20.4 kg (range, 11 to 55 kg). Two patients (9%) were cytomegalovirus (CMV) seropositive and 9 of 19 patients (48%) were Epstein-Barr virus (EBV) seropositive preoperatively. Five of the donors (20%) were CMV seropositive. The most common indications for OLT were biliary atresia (8) and tyrosinemia (7). There were 4 deaths, for an overall mortality rate of 19%. In 3 patients, deaths were related to infection (CMV hepatitis and duodenitis with aortoduodenal fistula, adult respiratory distress syndrome [ARDS] with Streptococcus viridans pneumonia, Escherichia coli cholangitis with progressive hepatic failure). Fifteen patients (72%) had 41 major infections, most of them bacterial, during the first month posttransplantation. These include pneumonia (25%), line sepsis (17%), cholangitis (14%), and tracheitis (14%). There was only one major viral infection, a CMV hepatitis that occurred in the first month posttransplantation. Three patients had fungal infections (8%) associated with hepatic artery thrombosis and recurrent cholangitis. All three patients required retransplantation. There was only one protozoal infection (Pneumocystis carinii pneumonia) causing life-threatening respiratory failure, from which patient recovered without sequelae. Infection still remains a serious complication of OLT. Bacterial infection is common and is usually associated with technical complications. The low rate of CMV infection is related to low incidence of CMV in the donor pool and the minimal use of strong immunosuppressants.