Introduction: In recent years, advances have continued to prolong kidney graft survival, and the population of long-term survivors has grown. Information concerning clinical care and management of this unique population, however, is lacking.
Methods: A retrospective cohort analysis was conducted on kidney transplants performed at our institution between November 1988 and December 2002. In this period, 135 transplantation (Tx) procedures were performed here. Recipients with primary non-functioning or early graft loss within 6 months (n = 10), recipients transferred to other hospitals (n =6) and pediatric patients less than 15 years of age (n =2), were excluded. Enrolled patients were followed until the end of the observation period in December 2023. Medical records regarding the recipient and donor demographics, the issues concerning Tx, clinical event following Tx, graft function modulation, and histopathological findings of the graft biopsy just prior to graft failure were collected and analyzed.
Results: Thirty-six of 117 recipients studied (30.8%) were alive with functioning grafts for 20 years or more. Among this population, living donor grafts were used in 75% of recipients. Mean estimated glomerular filtration rate (eGFR) of the 36 survivors at 20 years after Tx was significantly lower than eGFR at base-line (48.1 ± 18.7 versus 62.8 ± 18.5 mL/min/1.73 m2, respectively: p < 0.001). Antibodies against human leucocyte antigens were found in 10 of 36 (27.8%) and in 3 patients, these antibodies were identified with donor specificity. Patients were evaluated for a mean period of 27.0 ± 0.4 (median, 26.7) years. Twenty years after Tx during the observation period, 8 grafts failed, including 1 recipient with a functioning graft (graft survival rate: 77.8%). The Cox proportional hazard multivariate analysis revealed that the eGFR rate of decline (eGFR rate of decline = baseline eGFR - eGFR at 20 years after Tx / baseline eGFR × 100) was only a risk factor for graft loss after Tx (relative risk = 1.040; 95% confidence interval; 1.006 - 1.074; p = 0.019). In graft biopsies performed in 7 patients with subsequent death-censored graft failure, the main histopathological diagnosis was interstitial fibrosis/tubular atrophy of more than grade Ⅱ in 4 patients, recurrent or de novo glomerulonephropathy in 2 patients and chronic active antibody-mediated rejection in 1 patient.
Conclusion: Seven grafts in the cohort we studied failed after two decades because of chronic irreversible pathophysiology, glomerulonephritis, or antibody-mediated rejection. However, only one patient died with a functioning graft. Graft failure was not as rare during those periods. These results suggest careful monitoring of both patient and graft, including an appropriate histopathological evaluation, would be needed to improve graft survival, even 20 years after kidney Tx.