Prolonged Cold Ischemia Time Offsets the Benefit of Human Leukocyte Antigen Matching in Deceased Donor Kidney Transplant.

BACKGROUND

The consequences of prolonging cold ischemia time (CIT) to facilitate HLA matching in kidney transplantation are not known.

METHODS

Patients with a history of kidney transplant in the United States (2000-2016) with 0 HLA mismatch (MM) were categorized based on CIT (< 10; 10 to < 15; 15 to < 20; 20 to < 25; 25 to < 30; and ≥ 30 hours). Time to graft loss was compared for each CIT category to a reference group of individuals with > 0 HLA MM and short CIT (< 10 hours) using a multivariable Cox proportional hazards model.

RESULTS

The adjusted risk of graft failure was significantly lower for 0 HLA MM with the shortest CIT compared to the reference group (hazard ratio, 0.82; 95% confidence interval, 0.72-0.94), and this survival advantage persisted to a threshold of < 20 hours of CIT. No survival advantage was observed for the 0 HLA MM group once CIT was > 20 hours. This trend persisted after excluding highly sensitized recipients (panel reactive antibody > 98%) where shipping of organs occurs to achieve more equitable access to organs rather than optimize HLA match.

CONCLUSIONS

CIT > 20 hours offsets the benefit of 0 HLA MM in kidney transplantation. This may have implications in organ shipping to facilitate immunologic match.