Association between Reperfusion Renal Allograft Biopsy Findings and Transplant Outcomes

Abstract

Biopsy findings at the time of procurement of deceased donor kidneys remain the most common reason cited for kidney discard. To determine the value of renal allograft histology in predicting outcomes, we evaluated the significance of histologic findings, read by experienced renal pathologists, in 975 postreperfusion biopsy specimens collected from 2005 to 2009 after living donor (=427) or deceased donor (=548) renal transplant. We evaluated specimens for the degree of glomerulosclerosis, interstitial fibrosis and tubular atrophy, and vascular disease; specimens with a score of 0 or 1 (scale, 0-3) for each parameter were considered optimal. Overall, 66.3% of living donor kidneys and 50.7% of deceased donor kidneys received an optimal histology score (<0.001). Irrespective of donor status, suboptimal kidneys came from older donors with a higher incidence of diabetes mellitus, hypertension, and obesity and a higher mean kidney donor risk index (all <0.001). Death-censored outcomes after transplant differed significantly between optimal and suboptimal kidneys only in the deceased donor transplants (=0.02). Regardless of histologic classification, outcomes with deceased donor kidneys were inferior to outcomes with living donor kidneys. However, 73.2% of deceased donor kidneys with suboptimal histology remained functional at 5 years. Our findings suggest that histologic findings on postreperfusion biopsy associate with outcomes after deceased donor but not living donor renal transplants, thus donor death and organ preservation-related factors may be of greater prognostic importance. Discarding donated kidneys on the basis of histologic factors may be inappropriate and merits further study.

Procurement Biopsies in the Evaluation of Deceased Donor Kidneys

“…This finding is consistent with prior reports, and it underscores the concern that the tissue in wedge biopsies contains disproportionately subcapsular parenchyma and therefore, likely results in over-representation of the degree of glomerulosclerosis and interstitial fibrosis and tubular atrophy compared with needle core biopsies. This sampling issue is likely a contributor to the increased rate of discards attributed to biopsy findings, especially in instances of unilateral discards (18). However, research is needed on the effect of biopsy technique on risk of postimplantation bleeding, because a theoretical increase in the risk of bleeding with core needle biopsies (due to potentially higher risk of larger vessels) plays a large role in some centers' preference for wedge biopsies (21).…”

“…Both procurement and reperfusion biopsy reports were evaluated for degree of glomerulosclerosis, interstitial fibrosis and tubular atrophy, and vascular disease. For each of these histologic parameters, we assigned a rating of zero (best) to three (worst) on the basis of the pathologists' assessment (definitions are in Table 1) (18). Kidneys were further assigned an "optimal" rating if they had either zeroes or ones for each of the histologic parameters.…”

“…Kidneys were further assigned an "optimal" rating if they had either zeroes or ones for each of the histologic parameters. Kidneys that rated more than one on at least one of the three histologic parameters were assigned a "suboptimal" rating, consistent with prior data (18). We extracted additional DonorNet data from procurement biopsies when available, including biopsy location, wedge versus core, and staining/processing methodology, although these data were not consistently available.…”

“…We previously showed that reperfusion biopsies have prognostic value for deceased donor kidney transplant but not living donor kidney transplant recipients (18). Nevertheless, deceased donor allografts with suboptimal histology had reasonable intermediate-term outcomes, underscoring the value of these organs for at least a subset of patients (2,18). However, reperfusion biopsies performed at implantation are, by definition, unavailable before transplantation and thus, have no effect on the decision to accept/reject an organ.…”

“…However, reperfusion biopsies performed at implantation are, by definition, unavailable before transplantation and thus, have no effect on the decision to accept/reject an organ. In contrast to procurement biopsies, reperfusion biopsies are performed under ideal circumstances, and they are read by experienced kidney pathologists using multiple special stains (18). Procurement biopsies are frequently wedge biopsies, and due to time constraints, they are processed as frozen sections, typically using a single stain, and read frequently by on-call pathologists who may or may not have additional training in kidney pathology (5,10,18).…”