Data from: Clinical complications and outcomes of angiographically negative subarachnoid hemorrhage

Objective: To define the in-hospital course, complications, short- and long-term functional outcomes of patients with angiographically negative subarachnoid hemorrhage (anSAH), particularly those with aneurysmal-pattern anSAH (aanSAH). Methods: Retrospective cohort study of patients with aneurysmal subarachnoid hemorrhage (aSAH), aanSAH and perimesencephalic-pattern anSAH (panSAH) treated at a single tertiary referral center between January 2006 and April 2018. Ninety-nine patients with anSAH (33 aanSAH and 66 panSAH) and 464 patients with aSAH were included in this study. Outcomes included symptomatic hydrocephalus requiring CSF drainage, need for ventriculoperitoneal shunt (VPS), radiographic vasospasm, delayed cerebral ischemia (DCI), radiographic infarction, disability level within one year of ictus and at last clinical follow-up as defined by modified Rankin Scale (mRS). Results: Patients with aanSAH and panSAH had similar rates of DCI and radiologic infarction, and patients with aanSAH had significantly lower rates compared to aSAH (P≤0.018). Patients with aanSAH were more likely than those with panSAH to require temporary CSF diversion and VPS (P≤0.03), with similar rates to those seen in aSAH. Only one patient with anSAH died in the hospital. Compared to those with aSAH, patients with aanSAH were significantly less likely to have a poor functional outcome within one year of ictus (OR 0.26, 95% CI 0.090 – 0.75) and at last follow-up (HR 0.30, 95% CI 0.19 – 0.49, P=0.002). Conclusions: DCI is very uncommon in anSAH, but patients with aanSAH have a similar need for short- and long-term CSF diversion to patients with aSAH. Nevertheless, patients with aanSAH have significantly better short- and long-term outcomes.