Investigating the threshold for early renal allograft biopsy: A South African single-centre perspective.

Background: The most common clinical indication for renal biopsy in the early post-transplant period is early graft dysfunction (EGD), which may present either as delayed graft function (DGF) or acute graft dysfunction. Even though it is a valuable diagnostic tool, renal allograft biopsy is not without risk of major complications. Recent studies have suggested that, with modern immunosuppressive induction regimens and more accurate ways to determine high immunological risk transplants, early acute rejection (AR) is uncommon and routine biopsy for EGD does not result in a change in management.

Objectives: To describe the histological findings and complications of renal allograft biopsies for EGD in our setting, and to determine whether our current threshold for biopsy is appropriate.

Methods: This study was a retrospective audit that included all patients who underwent renal allograft biopsy within the first 30 days of transplantation at Groote Schuur Hospital, Cape Town, South Africa, from 1 June 2010 to 30 June 2018. The indication for biopsy was any patient who showed significant EGD, characterised by acute graft dysfunction or DGF with dialysis dependence.

Results: During the study period, 330 patients underwent renal transplantation, of whom 105 (32%) had an early biopsy and were included in the study. The median age of recipients was 39 (range 17 - 62) years, with 65% males and 35% females. The majority of donors were deceased donations after brain death (70%), with an overall median cold ischaemic time of 9 hours (interquartile range (IQR) 4 - 16). The average number of human leukocyte antigen mismatches was 5 (IQR 4 - 7). A donor-specific antibody was recorded for 18% of recipients and a panel-reactive antibody score of >30% was recorded for 21%. The median duration after transplant for biopsy was 8 (IQR 6 - 10) days. During the first month of EGD, AR was diagnosed in 42% of patients who underwent biopsies. In 21% of these patients, there was acute cellular rejection, in 16% antibody-mediated rejection, and in 5% both of these. Acute tubular necrosis was the primary finding in 32%, with acute interstitial nephritis in 8%, and acute calcineurin toxicity in 4% of cases. A significant biopsy-related complication was recorded in 3 patients: 1 small-bowel perforation repaired via laparotomy, and 2 vascular injuries successfully embolised by interventional radiology.

Conclusions: Considering the relative safety and high rate of detection of AR, a liberal approach to renal biopsy for EGD remains justifiable in our setting.