Onset of Donor Warm Ischemia Time in Donation After Circulatory Death Liver Transplantation: Hypotension or Hypoxia?

Abstract

The aim of this study was to investigate the impact of hypoxia and hypotension during the agonal phase of donor warm ischemia time (DWIT) on hepatic ischemia/reperfusion injury (IRI) and complications in donation after circulatory death (DCD) liver transplantation. A retrospective single-center study of 93 DCD liver transplants (Maastricht type III) was performed. DWIT was divided into 2 periods: the agonal phase (from withdrawal of treatment [WoT] until circulatory arrest) and the asystolic phase (circulatory arrest until cold perfusion). A drop to <80% in peripheral oxygenation (SpO ) was considered as hypoxia in the agonal phase (SpO -agonal) and a drop to <50 mm Hg as hypotension in the agonal phase (SBP-agonal). Peak postoperative aspartate transaminase level >3000 U/L was considered as severe hepatic IRI. SpO dropped within 2 minutes after WoT <80%, whereas the systolic blood pressure dropped to <50 mm Hg after 9 minutes, resulting in a longer SpO -agonal (13 minutes) than SBP-agonal (6 minutes). In multiple logistic regression analysis, only duration of SpO -agonal was associated with severe hepatic IRI (P = 0.006) and not SBP-agonal (P = 0.32). Also, recipients with long SpO -agonal (>13 minutes) had more complications with a higher Comprehensive Complication Index during hospital admission (43.0 versus 32.0; P = 0.002) and 90-day graft loss (26% versus 6%; P = 0.01), compared with recipients with a short SpO -agonal (≤13 minutes). Furthermore, Cox proportional hazard modeling identified a long SpO -agonal as a risk factor for longterm graft loss (hazard ratio, 3.30; 95% confidence interval, 1.15-9.48; P = 0.03). In conclusion, the onset of hypoxia during the agonal phase is related to the severity of hepatic IRI and postoperative complications. Therefore, SpO <80% should be considered as the start of functional DWIT in DCD liver transplantation.

Evaluation of Liver Graft Donation After Euthanasia

“…Research has shown that an oxygen saturation of less than 80% should be considered as the start of the functional DWIT. 20 However, in LTs with DCD-V grafts, the donor oxygen saturation and blood pressure levels are often not measured. In the few cases in which these parameters were measured, it was done noninvasively to minimize harm to the patient.…”

“…Secondary outcomes were the occurrence of early allograft dysfunction, hepatic artery thrombosis, and nonanastomotic biliary strictures within the first year after the LT. As described, the DWIT can be divided into an agonal phase and an asystolic phase. 20 In an LT with DCD-V graft, the agonal phase was defined as the time between administration of euthanatics (coma-inducing drug and nondepolarizing neuromuscular blocking agent) and circulatory arrest. In an LT with DCD-III graft, the agonal phase was defined as the period between withdrawal of life-supporting treatment and circulatory arrest.…”

Disparities in DCD organ procurement policy from a national OPO survey: A call for standardization

“…Hypoperfusion longer than 20 minutes following withdrawal of care correlates with LT failure . Kalisvaart et al showed that hypoxia was a better indicator for graft loss and suggested SpO 2 below 80% for onset of WIT.…”

“…Other investigators have linked decreased oxygen during the agonal phase to poor outcomes for LT and KT . Specifically, a prolonged period with SpO 2 levels below 80% during the agonal phase is detrimental to graft quality and resulted in unsuccessful graft retrieval .…”

“…Other investigators have linked decreased oxygen during the agonal phase to poor outcomes for LT and KT . Specifically, a prolonged period with SpO 2 levels below 80% during the agonal phase is detrimental to graft quality and resulted in unsuccessful graft retrieval . Reports focused on kidney procurement suggest that even an agonal period as long as 5 hours can yield transplantable organs if able to pass machine perfusion viability screening .…”