The relationship between histological findings of preimplantation kidney biopsies and pump resistive index (RI) values during machine preservation and allograft survival remains unclear due to conflicting results between different studies.Objective
To determine the association between histological findings of preimplantation kidney biopsies and pump resistive index values and short-term graft survival (up to 3 years post-transplant).Methods
We performed a retrospective review of all patients who received a kidney-only transplant between January 1, 2009, and December 31, 2014, at our center and followed-up until December 1, 2016. Patients who died with a functioning allograft were excluded from analysis. Obsolete glomerulosclerosis was divided into 3 groups (< 10%, 10-20%, and > 20%), intimal arterial narrowing was divided into 3 groups (< 10%, 11-25% and > 25%) and RI was divided into 5 groups (0.00-0.09, 0.10-0.19, 0.20-0.29, 0.30-0.39 and 0.40=0.49). The log-rank test was used to test if there is a significant difference in different RI groups in terms of the probability of survival.Results
A total of 662 patients received kidney-only transplants in our study period. 506 of 662 received deceased donor kidneys and were included in our analysis with 21% Caucasian, 47% African American, and 31% Hispanic. The median age was 53.6 (range, 21.1-79.2) and 58% were male. 57% of deceased donors were standard, 31% expanded and 12% donation after cardiac death donors with a median KDPI of 62. During a median follow-up time of 36 months (range, 23-94), 51 patients lost their allografts (death-censored graft survival 90%). There was no difference in terms of patients’ age, sex, race, etiology of kidney disease, type of induction agent, and cold ischemia time when graft loss patients are compared to patients with functioning allograft. The graft loss group had higher KDPI (71 vs. 61, p=0.03) and received more expanded criteria donor (49% vs. 29%, p=0.01). Percent of obsolete glomerulosclerosis and arterial intimal narrowing in preimplantation biopsies showed no association with short-term allograft failure at 1, 2, and 3 years. RI was a strong predictive factor for short-term allograft failure. Kidneys in different RI categories have significantly different survival experiences in 1, 2, and 3 years (p=0.030, p=0.001, p=0.008, respectively). RI > 0.4 performed worse than other RI groups as seen in Figure 1 (Figure 1 shows 3 year Kaplan-Meier graft survival).Conclusions
Recipients of higher KDPI score and expanded criteria donor were at higher risk for allograft failure. Percent of obsolete glomerulus and arterial narrowing in preimplantation biopsies did not predict short-term allograft failure. However, RI was a strong predictive factor for short-term allograft failure.