The venous delay phenomenon in computed tomography angiography: A novel imaging outcome predictor for poor cerebral perfusion after severe aneurysmal subarachnoid hemorrhage

OBJECTIVE Diverse treatment results are observed in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). Significant initial perfusion compromise is thought to predict a worse treatment outcome, but this has scant support in the literature. In this cohort study, the authors correlate the treatment outcomes with a novel poor-outcome imaging predictor representing impaired cerebral perfusion on initial CT angiography (CTA). METHODS The authors reviewed the treatment results of 148 patients with poor-grade aSAH treated at a single tertiary referral center between 2007 and 2016. Patients with the "venous delay" phenomenon on initial CTA were identified. The outcome assessments used the modified Rankin Scale (mRS) at the 3rd month after aSAH. Factors that may have had an impact on outcome were retrospectively analyzed. RESULTS Compared with previously identified outcome predictors, the venous delay phenomenon on initial CTA was found to have the strongest correlation with posttreatment outcomes on both univariable (p < 0.0001) and multivariable analysis (OR 4.480, 95% CI 1.565-12.826; p = 0.0052). Older age and a higher Hunt and Hess grade at presentation were other factors that were associated with poor outcome, defined as an mRS score of 3 to 6. CONCLUSIONS The venous delay phenomenon on initial CTA can serve as an imaging predictor for worse functional outcome and may aid in decision making when treating patients with poor-grade aSAH.