The optimal time between clinical brain death diagnosis and confirmation using CT angiography: a retrospective study.

BACKGROUND: In several countries, a computed tomography angiography (CTA) is used to confirm brain death (BD). A six-hour interval is recommended between clinical diagnosis and CTA acquisition despite the lack of strong evidence to support this interval. The aim of this study was to determine the optimal timing for CTA in the confirmation of BD. METHODS: This retrospective observational study enrolled all adult patients admitted between January 2009 and December 2013 to the intensive care units of a French university hospital with clinically diagnosed BD and at least one CTA performed as a confirmatory test. The CTAs were identified as conclusive (e.g. yielding confirmation of BD) or inconclusive (e.g. showing persistent brain circulation). RESULTS: One hundred and four patients (sex ratio M/F 1.8; age 55 years [41-64]) underwent 117 CTAs. CTAs confirmed cerebral circulatory arrest in 94 cases yielding a sensitivity of 80%. Inconclusive CTAs were performed earlier than conclusive ones (2 hours [1-3] vs. 4 hours [2-9], P= 0.03) and were associated with decompressive craniectomy (5 cases [23%] vs. 6 cases [7%], P= 0.05) and the failure to complete full neurological examination (5 cases [23%] vs. 4 cases [5%], P= 0.02). Six hours after BD clinical diagnosis, the proportion of conclusive CTA was only 51%, with progressive increase overtime with more than 80% of conclusive CTA after 12 hours. CONCLUSIONS: A 12-hour interval might be appropriate in order to limit the risk of inconclusive CTAs.