Histopathologic evaluation of pretransplant biopsy as a factor influencing graft function after kidney transplantation: a 1-year observation.

BACKGROUND

Many factors affect long-term results in kidney transplantation including histologic damage as a independent predictor, such as chronic allograft/nephropathy in protocol biopsies and age-dependent lesions. Histopathologic findings correlate with the incidence of delayed graft function, renal function, and allograft survival, allowing a rather precise prediction of graft outcome.

METHODS

We analyzed 92 renal thick needle preimplantation and 29 postexplantation biopsies. Biopsies were preserved in 4% formalin and immersed in paraffin. Optimal biopsies contained at least 10 glomeruli and at least 2 cross-sections of arteries. We analyzed tubulitis, intensity of acute tubular necrosis, inflammatory infiltration, glomerulonephritis, arterial hyalinization, arteritis, fibrosis, tubular atrophy, arterial intimal fibrosis, increase of mesangial matrix, and percentage of glomerulosclerosis. During the postoperative course we analyzed patients condition, exigency of postoperative dialysis, urine output, as well as serum concentrations of creatinine, urea, uric acid, and ions. During a 1-year observation period, we analyzed living recipients, graft loss, death with a functioning graft, incidence of nephropathy (CAN), and acute rejection episodes (ARE).

RESULTS

We observed a significant correlation between immediate graft function (IGF) and lack of ATN in the pre-0 biopsy. We observed no correlation between renal function and arterial hyalinization and fibrosis, inflammatory infiltration, tubular atrophy. In the postoperative period, we observed a significant correlation between IGF and lack of interstitial fibrosis with significantly lower levels of creatinine, urea, and potassium and higher urine output early after transplantation. IGF and better function of the right kidney was correlated with shorter time to reach a creatinine level of 2 mg%. In the postoperative periods, we also observed a difference between renal function depending on gender. The presence of acute tubular necrosis, arterial fibrosis, lack of inflammatory infiltration in the pre-0 biopsy correlated with worse late renal function. Among explantation biopsies 65.5% showed signs of CAN, and 37.93%, histologic marks of ARE.