Time-Dependent Outcomes of Computed Tomography Angiography after Clinically Apparent Brain Death: A Retrospective Cohort Study

Aim of our study was to verify the impact of the time interval between appearance of BBA and CTA testing on the sensitivity of CTA applied for the confirmation of CCA during DNC determination procedures.
Material and methods: We recruited 118 ICU patients who underwent DNC determination including CTA. CTA data were acquired using two different techniques: conventional two-phase or timing-invariant CTA. To ascertain CCA during CTA, a 4-point scoring system introduced by the French Society of Neuroradiology was applied. According to time from BBA to CTA patients were divided in following groups: <6 h, 6-12 h, 12-18 h, 18-24 h, 24-48 h, 48-72 h, 72-96 h and >96 h.
Results: CTA was negative (non-confirmatory of CCA) in 15 out of 118 patients which yielded an overall sensitivity of 87.3% (95% CI: 78.6-91.1). Analysis of false-negative CTA results by timing after BBA indicated that 93% (14/15) of false negatives occurred within 12 hours. Based on these findings, a threshold of 12 hours emerged, dividing the study population into early (up to 12 hours; sensitivity of 61.1%) and late (>12 hours; sensitivity of 98.7%; p<0.001) groups for CTA performance after BBA.
Conclusions: In summary, this is the first publication directly illustrating relationship between time elapse after appearance of BBA and CTA sensitivity used for confirmation of CCA during DNC diagnostic procedures. We conclude that time elapse over 12 h after BBA appearance with sensitivity of 98,7% seems to be optimal for CTA testing and range between 6-12 h is still acceptable despite of lower sensitivity of 69,4%.