Abstract WP273: Off-Hour and Weekend Effects in Stroke-Related Brain Death Diagnosis and Organ Donation - A Nationwide Analysis from Germany

Introduction: Stroke is the leading cause of brain death (BD) and the main source of postmortem organ donors. Ancillary tests often support the clinical diagnosis, but their use may vary with structural and temporal factors. While off-hour effects are well described in acute stroke care, their impact on BD determination remains unclear. We investigated temporal patterns in ancillary test use and BD determination in a nationwide stroke cohort. Methods: We analyzed all patients with guideline-confirmed BD after stroke reported to the German Organ Procurement Organization from 04/2020 to 08/2025. Variables included age, sex, stroke subtype (acute ischemic stroke [AIS], intracerebral hemorrhage [ICH], subarachnoid hemorrhage [SAH]), ventilation duration, ancillary test modality (computed tomography angiography [CTA], transcranial Doppler sonography [TCD], electroencephalography [EEG], scintigraphy, brainstem auditory evoked potentials [BAEP], and somatosensory evoked potentials [SSEP]), timing of determination (off-hours [5pm-8am] vs. regular hours, weekdays vs. weekends) and postmortem organ donation. Results: Overall, 3,491 patients were included (median age 62 years [IQR 52–72], 45% male): 1,550 (44.4%) with ICH, 666 (19.1%) with AIS and 1,275 (36.5%) with SAH. Ancillary testing was performed in 2,910 cases (84.1%) and organ donation was realized in 2,647 cases (75.8%). Donation rates were higher during off-hours (79.4% vs. 75.2%, p=0.006) and weekends (80.7% vs. 74.5%, p< 0.001). In multivariable models, both off-hour (OR 1.28, 95%CI 1.07–1.52; p=0.006) and weekend determinations (OR 1.36, 95%CI 1.11–1.67; p=0.003) independently predicted higher donation rates, alongside younger age and stroke subtype. Ancillary practice shifted over the years with increasing CTA use (OR 1.07/year, 95%CI 1.02–1.11; p=0.003) and declining EEG (OR 0.94 per year, 95%CI 0.90–0.98; p=0.009). On weekends, CTA was more frequent (OR 1.21, 95%CI 1.03–1.43; p=0.023), but CTA itself was unrelated to donation (OR 0.97, p=0.69). Conclusions: Off-hour and weekend determinations of brain death after stroke were associated with higher organ donation rates. Although ancillary practice shifted toward CTA, this did not mediate the temporal donation effect. Instead, the off-hour and weekend effects appeared to act independently, suggesting that organizational/structural factors during these periods may facilitate donation and reflect system-level resilience in stroke-related neurocritical care.