Donor hemodynamic profile presages graft survival in donation after cardiac death liver transplantation

Abstract

Obligatory exposure to a period of warm ischemia is the defining feature of liver allografts from donation after cardiac death (DCD) donors. We explored novel methods for characterizing the dynamic aspects of donor warm ischemia that might be useful in assessing organ quality. The hemodynamic profile during donor warm ischemia was retrospectively studied for 110 Maastricht category III DCD donors. Three methods were used to summarize the hemodynamic changes after extubation: (1) the area under the systolic blood pressure curve (AUCSBP), (2) the slope of the systolic blood pressure regressed onto the time from extubation until cross-clamping, and (3) the slope of the systolic blood pressure regressed onto the time from extubation but calculated with only the values during the first 10 minutes after extubation (SBP10). Stepwise multivariate Cox models were created to study the association of these measures with graft survival. The duration of the donor warm ischemia time (23.6 ± 8.5 minutes) was not associated with graft survival (P = 0.35), although AUCSBP and SBP10 demonstrated significant associations (P = 0.02 and P = 0.05, respectively) in a univariate analysis. Multivariate regression models incorporating donor and recipient covariates indicated that among all covariates, SBP10 had the closest association with graft survival (hazard ratio = 1.08, P = 0.01). This association was even stronger when SBP10 was dichotomized into values above or below the median (-7.2 mm Hg/minute). Patients with SBP10s steeper than the median had an estimated 5-year graft survival rate of 76%, whereas patients with slopes less than the median had a 5-year survival rate of 45% (P < 0.007). In conclusion, the incorporation of novel methods for characterizing the donor warm ischemia time may help in selecting DCD liver allografts with favorable outcomes.