Art of Medicine: The Pre-Implantation Kidney Biopsy
The painting above shows normal glomeruli, tubulointerstitium, and a normal artery from a pre-implantation wedge biopsy. Pre-implantation wedge biopsies, also known as donor biopsies, procurement biopsies, or harvest biopsies, are performed for extended criteria donor kidneys, high risk recovered donor kidneys, or at the request of the transplant surgeon, to evaluate for suitability for transplantation. Over 40% of procured kidneys are discarded prior to transplantation. The use of preimplantation kidney biopsies, performed as frozen sections at transplant centers, may reduce the discard rate by accepting kidneys that are histopathologically acceptable, as well as to avoid transplantation of sub-optimal organs.
“Extended criteria donor” kidneys include those from decedents greater than 60 years of age, decedents greater than 50 years of age with a history of hypertension, a serum creatinine of greater than 1.5 mg/dL, or the cause of death being a cerebrovascular accident. Donor kidneys considered to be high risk by the kidney donor profile index (KDPI) include those with a score greater than 85%. The KDPI provides a weighted risk estimate based on the decedent’s age, height, weight, ethnicity, history of diabetes, history of hypertension, cause of death, serum creatinine, HCV status, and donor after circulatory death status (Rao et al, 2009). The predictive value of KDPI on allograft function and lifespan is approximately 60%, therefore, histopathologic assessment in conjunction with the KDPI is helpful in determining if a donor organ is suitable for transplantation.
A pre-implantation wedge biopsy should have at least 25 glomeruli and contain sampling of arteries. The Banff working group evaluated multiple histopathologic parameters in a study of 124 pre-implantation biopsies, which included the percentage of global glomerulosclerosis, interstitial fibrosis, tubular atrophy, arterial intimal fibrosis, arteriolar hyalinosis, glomerular fibrin thrombi, and acute tubular injury or acute tubular necrosis. There was poor concordance among pathologists for acute tubular injury in pre-implantation biopsies, particularly in frozen sections which have freezing artifacts. In addition, glomerular fibrin thrombi often resolve post-transplantation in recipients. They concluded that the percentage of global glomerulosclerosis, interstitial fibrosis, and arteriosclerosis should be assessed. The percentage of global glomerulosclerosis had the greatest correlation with graft function, with biopsies with greater than 20 percent global glomerulosclerosis having inferior graft function (Liapis et al, 2016). It is recommended, however, not to automatically discard donor kidneys with greater than 20 percent global glomerulosclerosis, but to evaluate in conjunction with clinical parameters on a case-by-case basis.
Liapis H, Gaut JP, Klein C, Bagnasco S, Kraus E, Farris III AB, Honsova E, Perkowska-Ptasinska A, David D, Goldberg J, Smith M, Mengel M, Haas M, Seshan S, Pegas KL, Howedel T, Paliwa Y, Gao X, Landsittel D, Randhawa P, and Banff Working Group. Banff Histopathological Consensus Criteria for Preimplantation Kidney Biopsies. American Journal of Transplantation 2016; 17 (1):
Rao PS, Schaubel DE, Guidinger MK, Andreoni KA, Wolfe RA, Merion RM, Port FK, Sung RS. A comprehensive risk quantification score for deceased donor kidneys: The kidney donor risk index. Transplantation. 2009;88(2):231-236.
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