Abstract 210: Brain death ancillary testing after the 2023 AAN guidelines: The need for CTA & DSA to focus on the brainstem arteries and veins.

Purpose We propose CTA as a stewarding screen and bridge to DSA, TCD or SPECT, for better resource‐utilization in establishing cerebral circulatory arrest (CCA) in scenarios of death by neurologic criteria (DNC) but incomplete clinical exam. French scoring systems focusing on brainstem perfusion are best‐suited to cases with apnea test unavailable, pediatric or trauma cases, or skull base fractures. Methods We critically appraised the current American Academy of Neurology (AAN) guidelines advocating for specific brain death ancillary testing (BDAT). Complementing with the World Brain Death Project (WBDP) Lewis A et al. JAMA 2020 and Srairi M et al. report in Eur J Radiol. 2020, our study establishes that a focus on arteries perfusing and veins draining the brainstem on CTA or DSA can yield accuracy with CCA gold standard. We substantiate this viewpoint with illustrations from clinical experience at a level 1 trauma center with clinical pearls and pitfalls in open skull cases, with pediatric and trauma challenges. Results The 2023 AAN DNC guidelines specify adult and pediatric metabolic abnormality ranges, but we posit in this scenario that neurophysiologic modalities may be preferred over DSA or SPECT. Trauma and pediatrics with open skull cases are left with DSA as sole accepted modality, with CTA deemed unacceptable by the guidelines, yet DSA is quite resource‐intensive. Preservation of cortical branches on CTA or DSA, SPECT islands of viable tissue under craniectomy sites, TCD not recommended in open skull situations, making angiographic nuclear and sonographic tests illogical choices in many cases in our experience. Skull base fractures and unsafe apnea tests represent the vast majority of scenarios requiring BDAT. In these cases, we used TCD of the VBJ, or CTA‐CTV focusing on the absence of brainstem venous drainage using the French scoring system, as more topographically pertinent and well‐suited. Conclusions BDATs have high false positive or negative rates due to particular clinical pitfalls. Our study proposes a new paradigm with topography‐based selection of the BDAT. This appraisal criticizes the guidelines for their blanket exclusion of EEG, N20, BAERs and CTA, especially in pediatric and trauma cases. Our experience applying French scores to CTA‐CTV focusing on the brainstem, when this is the cerebral region at play and clinically appropriate, allowed us to make DNC determinations more accurate and pertinent to each case. We call for a revalidation of CTA and comparison to DSA with same preconceived focus on brainstem arteriovenous flow. further, we look to subsequently prove that DSA is a superfluous tool in this redefined framework.