Surveillance kidney biopsies deemed safe for monitoring pediatric transplant recipients
Study results indicated that surveillance biopsies offer a safe way for health care providers to monitor pediatric kidney transplant recipients, allowing for the identification of modifiable pathologies such as subclinical rejection.
Before the publication of this report, there were only eight publications on the topic of surveillance kidney biopsies in this patient population, according to Bradley A. Warady, MD, of the division of pediatric nephrology at Children’s Mercy Kansas City.
“We have been conducting surveillance biopsies for a number of years and wanted to evaluate the risk-benefit ratio of the procedure so that we could properly inform patients and families,” Warady told Healio Nephrology. “This study provides evidence to clinicians caring for pediatric kidney transplant patients on the safety and value of the procedure.”
Warady added that the study is the largest of its kind conducted in North America.
For the investigation, Warady and colleagues conducted a retrospective review of 215 kidney surveillance biopsies that were obtained from 97 pediatric patients (younger than 22 years of age at time of transplant) who were transplanted at Children’s Mercy Kansas City between 2008 and 2015. Patients transplanted with both deceased and living donor allografts were included.
The researchers wrote that while all patients received an induction immunosuppression of methylprednisolone and basiliximab, the standard maintenance immunosuppressive regimen of tacrolimus, mycophenolate mofetil and prednisone could be altered.
The safety of the procedure was determined by complications that occurred within 3 months of each surveillance biopsy (major complications included formation of AV fistulas, loss of allograft, infection, intestinal perforation and death; minor complications consisted of “anything that prolonged hospitalization beyond the post-procedural observational stay, including macroscopic hematuria, self-limited perinephric hematomas, transient fever and pain associated with the procedure”).
Of total surveillance biopsies performed, 34.4% occurred at 6 months after transplantation, 36.3% at 12 months and 29.3% at 24 months.
Researchers observed potentially modifiable histologic changes in 38.1% of all surveillance biopsies (36.5% in those performed at 6 months, 30.8% at 12 months and 49.2% at 24 months).
They also determined that subclinical rejection occurred with increasing frequency across all time points, with an estimated 49% increase in the odds of a subclinical rejection finding per additional 6 months post-transplantation (adjusted OR = 1.49).
When examining follow-up biopsies in patients who underwent treatment for subclinical rejection, the researchers found 50% had no subclinical rejection and 18.8% showed histologic improvement.
Regarding the safety of the procedure, the complication rate associated with surveillance biopsy was 1.9% (four out of 215) and consisted of only minor complications.
“Parents and patients have readily accepted performance of the procedure as they recognize that the results of the surveillance biopsy may positively impact the management of their child’s transplant, and the procedure itself is safe with only rare, minor complications,” Warady said.
He noted that researchers from his institution will continue to collect information on the outcomes of these biopsies, while evaluating the impact of the procedure and the subsequent modifications of therapy on long-term transplant outcomes.
“We will also continue to analyze our data to help define the optimal timing of these biopsies,” he added.