Knowing When to Ignore the Numbers: Single-Center Experience Transplanting Deceased Donor Kidneys with Poor Perfusion Parameters.

Background: Hypothermic machine perfusion is frequently used in evaluating marginal kidneys with poor perfusion parameters (PPP) contributing to delays in kidney placement or discard. We examined outcomes in deceased donor kidney transplants with PPP compared with those with optimal perfusion parameters (OPP).

Study Design: We conducted a retrospective single-center cohort study from 2001 to 2021 comparing PPP (n = 91) with OPP (n = 598) deceased donor kidney transplants. PPP was defined as terminal flow ≤80 mL/min and terminal resistance ≥0.40 mmHg/mL/min. OPP was defined as terminal flow ≥120 mL/min and terminal resistance ≤0.20 mmHg/mL/min.

Results: Mean terminal flow was PPP 66 ± 16 vs OPP 149 ± 21 mL/min and resistance was PPP 0.47 ± 0.10 vs OPP 0.15 ± 0.04 mmHg/mL/min (both p < 0.001). Donor age, donation after cardiac death, and terminal serum creatinine levels were similar between groups. Mean Kidney Donor Profile Index was higher among PPP donors (PPP 65 ± 23% vs OPP 52 ± 27%, p < 0.001). The PPP transplant group had more females and lower weight and BMI. Delayed graft function was comparable (PPP 32% vs OPP 27%, p = 0.33) even though cold ischemia times trended toward longer in PPP kidneys (PPP 28 ± 10 vs OPP 26 ± 9 hours, p = 0.09). One-year patient survival (PPP 98% vs OPP 97%, p = 0.84) and graft survival (PPP 91% vs OPP 92%, p = 0.23) were equivalent. PPP did predict inferior overall and death-censored graft survival long-term (overall hazard ratio 1.63, 95% CI 1.19 to 2.23 and death-censored hazard ratio 1.77, 95% CI 1.15 to 2.74). At 1 year, the estimated glomerular filtration rate was higher with OPP kidneys (PPP 40 ± 17 vs OPP 52 ± 19 mL/min/1.73 m 2 , p < 0.001).

Conclusions: Short-term outcomes in PPP kidneys were comparable to OPP kidneys despite higher Kidney Donor Profile Index and longer cold ischemia times, suggesting a role for increased utilization of these organs with careful recipient selection.