Hypothermic Machine Perfusion Allows Safe Delay in Kidney Transplantation After Cold Storage

Area of Science:

• Nephrology
• Transplantation immunology
• Surgical innovation

Background:

• Static cold storage (SCS) is the standard for kidney preservation.
• Prolonged hypothermic machine perfusion (HMP) is increasingly used to extend preservation times.
• The impact of sequential SCS followed by HMP (SCS+HMP) on kidney transplant outcomes requires further definition.

Purpose of the Study:

• To compare transplant outcomes between kidneys preserved with SCS followed by prolonged HMP (SCS+HMP) and SCS alone.
• To evaluate the incidence of primary graft non-function (PNF) and delayed graft function (DGF).
• To assess patient and death-censored graft survival and renal function over 24 months.

Main Methods:

• Single-center retrospective study of 200 adult kidney transplant recipients from brain-dead donors.
• Comparison of SCS+HMP (n=67) versus SCS alone (n=133) groups.
• Propensity score matching was used to adjust for baseline differences; outcomes analyzed included PNF, DGF, survival, and renal function.

Main Results:

• The SCS+HMP group experienced longer total cold ischemia times (1545 vs. 1104 min).
• After matching, DGF was significantly lower in the SCS+HMP group (17.6% vs. 39.2%, p=0.027).
• HMP was independently associated with lower odds of DGF (OR 0.34). PNF, patient survival, death-censored graft survival, and renal function were comparable between groups at 24 months.

Conclusions:

• Sequential HMP following initial SCS is a feasible strategy for extended kidney preservation.
• This approach is associated with a reduced incidence of delayed graft function.
• The SCS+HMP strategy does not compromise long-term patient survival, graft survival, or renal function.