Trajectories of Systolic Blood Pressure Decline in Kidney Donors After Circulatory Death and Delayed Graft Function

Abstract Background: Kidneys donated after circulatory death (DCD) suffer a period of functional warm ischemia before death. This study aimed to assess the risk of delayed graft function (DGF) using patterns of trajectories of systolic blood pressure (BP) decline in DCD kidneys. Methods: We studied all Australian DCD kidneys transplanted between 2014 - 2019, divided in a derivation (n=462, April 2014-January 2018) and validation (n=324, January 2018-December 2019) cohort, using latent class models and two-stage linear mixed-effect models. Results: Eight different trajectories, with distinct patterns of systolic BP decline, were identified. Compared to recipients of donors with the fastest decline in systolic BP after withdrawal of cardio-respiratory support, the adjusted odds ratios (OR) (95%CI) for DGF in recipients who had received donors with the slowest systolic BP decline were 0.36 (0.16 – 0.80, random forest model) and 0.38 (0.17 – 0.86, least absolute shrinkage and selection operator models, LASSO), respectively. For every 1 mmHg per minute reduction in the rate of decline of systolic BP, the adjusted OR (95%CI) for DGF were 0.95 (0.91-0.99). Similar comparison was conducted in the validation cohort. Recipients who received donors with the slowest systolic BP decline from withdrawal of cardio-respiratory support till death did not experience an increased risk of DGF (Adjusted OR (95%): random forest: 1.01 (0.42-4.2) and LASSO: 1.17 (0.5-2.74)). Conclusions: In DCD kidney donors, a slow decline in systolic BP during the agonal phase was not associated with adverse short-term outcomes after transplantation.