Biopsy Best in Pediatric Liver Transplant Dysfunction

Kate Johnson

March 19, 2014

VIENNA — Ultrasound-guided liver biopsy is safe and informative, and should be performed in all children with liver dysfunction who have undergone liver transplantation, a new study suggests.

"Our study is one of the few available that confirms the safety of biopsy in pediatric liver transplant patients," said researcher Kelvin Cortis, MD, from the Mediterranean Institute for Transplantation and Advanced Specialized Therapies in Palermo, Italy.

Because biopsy is an invasive procedure, there is always interest in less invasive investigations, such as liver function tests and ultrasound, he told Medscape Medical News.

"These data justify the continued use of biopsy, given the potential impact on management," he said. "Keep in mind that a biopsy is only done in problematic cases, where graft function is suboptimal. If we detect any potentially reversible problem early, it might change the prognosis for these children very significantly."

First results of the retrospective study, presented here at the European Congress of Radiology 2014, were published in the Journal of Pediatric Gastroenterology and Nutrition (Published online February 5, 2014).

The researchers evaluated 219 biopsies from 85 children who had undergone liver transplantation. The mean age of the patients was 7 years.

The reason for biopsy was suspected rejection with cholestasis in 43% of the cohort, altered liver function tests in 27%, suspected rejection in 24%, and protocol in 6%.

The 58% of biopsies performed more than a year after transplantation were considered late biopsies; the 42% performed within a year were considered early.

The day before biopsy, all patients underwent ultrasound liver function testing to measure total bilirubin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase. They also underwent ultrasound testing.

The ultrasound parameters analyzed included portal vein velocity, main hepatic arterial resistance index, hepatic vein flow pattern, and the presence of bile duct dilatation.

The biopsies were performed with a percutaneous substernal spring-loaded automatic biopsy needle under real-time ultrasound guidance. The puncture site was manually compressed for 10 minutes after each procedure.

Patients were under heavy sedation with spontaneous respiration and additional anesthesia was administered at the puncture site.

No patient required surgical or radiological intervention because of biopsy complications, Dr. Cortis noted. Two patients required transfusion after experiencing a drop in hematocrit, "but we didn't do any intervention to stop the bleeding; it stopped spontaneously," he reported.

The biopsies revealed a wide range of pathologies. Cholestasis (P = .003) and acute rejection (P = .027) were significantly more common in those who underwent early biopsy, and chronic rejection (P = .017) was significantly more common in those who underwent late biopsy.

Table. Biopsy Findings

Outcome Early Biopsy, % Late Biopsy, %
No pathology 16 24
Fibrotic diseases 4 12
Inflammatory diseases 15 15
Cholestasis 36 18
Acute rejection 13 5
Indeterminate acute rejection 11 7
Chronic rejection 4 14
Other 0 5

 

The researchers found no strong correlation between histopathology and either liver function tests or ultrasound parameters.

"Ultrasound-guided percutaneous liver biopsy in pediatric liver transplant recipients is routinely motivated by the possibility of allograft rejection, which is not rare. In fact, it's quite common," said Dr. Cortis.

"The rate of complications after ultrasound-guided liver biopsy in children is low. This is quite important, given that we are dealing with small liver grafts, and that most of the data available on complications after liver biopsy come from adult cohorts," he added.

"Histology consolidates the diagnosis of transplant rejection, and can yield more information that could have an effect on the management of these children, as a whole," Dr. Cortis explained. "Nonhistologic data, including liver biochemistry and ultrasound findings, do not predict the histopathologic outcome, and cannot replace liver biopsy as yet."

These findings offer "no real data to change practice," noted Khalid Khan, MD, a pediatric gastroenterologist and transplant specialist at the Transplant Institute and International Center for Liver Diseases at Georgetown University Hospital in Washington, DC.

"They tell us only that the complication rate is low with this method," he told Medscape Medical News.

However, the fact that the complication rate with ultrasound-guided biopsy was low in these children is worth investigating, Dr. Khan added.

"There are situations where an ultrasound-guided biopsy is technically warranted," he said. "For instance, in very small infants when the biopsy needle is much longer than the size of the liver and needs to be guided to prevent injury to other organs and when biopsy is required of a specific part of the liver."

Adult liver biopsy, however, is routinely done without any ultrasound guidance. "It would be useful to know if there is any benefit to using ultrasound, such as a lower complication rate," said Dr. Khan.

Dr. Cortis and Dr. Khan have disclosed no relevant financial relationships.

European Congress of Radiology (ECR) 2014: Abstract B-0793. Presented March 10, 2014.

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