Clinical Impact of Subclinical Interstitial Fibrosis or Tubular Atrophy in 1-Hour Allograft Biopsy for Remnant Renal Function in Living Kidney Donors: A Prospective Observational Study.

ABSTRACT Background Preservation of remnant renal function (RRF) is one of the major concerns among living kidney donors (LKDs). A comprehensive assessment is needed to predict the RRF. In this prospective study, we investigated the roles of histologic findings from a 1-hour allograft biopsy in predicting the RRF. Methods Our prospective study included 116 LKDs who underwent donor nephrectomy (DN) at our institute. Clinical and radiographic data were obtained from their medical charts. Renal volume parameters were calculated using the preoperative computed tomographic images in the volume analyzer SYNAPSE VINCENT image analysis system. Tissues obtained from allograft biopsy were examined. RRF was defined as the estimated glomerular filtration rate (eGFR) 12 months after DN. Results Of 116 LKDs, 95 were finally evaluated. The median age of the LKDs at DN and the preoperative eGFR were 57 years and 80.0 mL/min/1.73 m2, respectively. In the histologic analysis, 68 allografts (71.6%) had nonspecific findings involving the glomerulus, vessel, and tubulointerstitium. Interstitial fibrosis or tubular atrophy (IF/TA) was the only significant predictive factor for RRF (P = .039). No significant association was found between renal volume parameters and IF/TA, whereas remnant renal volume adjusted by body weight (RRV/BW) tended to be relatively correlated with IF/TA (P = .072). Furthermore, LKDs with subclinical IF/TA tended to have decreased RRV/BW compared with those without subclinical IF/TA (P = .088). Conclusions Our findings suggested that the presence of IF/TA could be a predictive factor for RRF after DN. Further research establishing the predictive model for RRF is warranted to improve the outcomes of LKDs.