Frozen Section Evaluation of Preimplantation Donor Kidneys

Abstract

The benefits of renal transplantation for patients with endstage renal disease on hemodialysis are well established, but currently there is a significant shortage of organs available for transplantation. In an effort to increase the size of the donor pool, donors that may have been excluded from donating previously are currently accepted. Frozen section evaluation of preimplantation donor kidney biopsies is particularly important for organs from these expanded criteria donors, both to determine organ suitability and as a tool to predict short-and long-term graft survival. Although significant progress has been made in the field, controversy still remains regarding the predictive value of the individual pathologic parameters to predict graft outcome. The Maryland Aggregate Pathology Index score is based on the identification of 5 histologic parameters and is used to stratify donor organs into low-, intermediate-, and high-risk groups, which correlate with overall graft survival. Irrespectively of the transplant donor population, preimplantation donor kidney frozen section evaluation is an invaluable tool for optimal use of the available organs.A 62-year-old white woman with a 15-year history of type 2 diabetes mellitus, obesity, and hypertension was admitted for an ischemic cerebral stroke and ultimately died despite appropriate medical treatment. After discussion with the family, it became clear that the patient wished to be an organ donor, and both kidneys were harvested for further evaluation. During the course of the disease, the patient had a good renal function with a terminal serum creatinine level of 1.5 mg/dL. On the basis of the clinical information, the patient was categorized as an expanded criteria donor (ECD; refer to the next sections). Pathologic EvaluationWedge biopsies of each kidney were submitted for frozen section preimplantation analysis. The biopsies measured a mean of 1.4 Â 0.8 Â 0.4 cm. The specimens were blotted dry and snap frozen in liquid nitrogen. Routinely prepared 5-Km-thick sections, stained with hematoxylin and eosin, were evaluated.Global evaluation of the frozen sections at low magnification demonstrated preserved renal cortex with an adequate number of glomeruli (mean, 62 per section). Similar findings were observed in the left and right kidneys, with global glomerular sclerosis of 17% and 20%, respectively. There were small scattered areas of tubulointerstitial atrophy (scarring) that affected up to 15% of the overall cortical surface.Two to 4 interlobular arteries were present in each section, and in the most affected arteries, there was moderate narrowing due to arteriosclerosis (wall-to-lumen ratios [WLRs], Q0.5). Many arterioles (glomerular-size, preglomerular) had thickening of their walls due to hyalinosis.