Patients with nontraumatic subarachnoid hemorrhage (SAH) with normal angiogram results, or nonaneurysmal SAH (anSAH), had better functional outcomes than patients with aneurysmal SAH (aSAH), according to a study published in Neurology.

The investigators of this retrospective cohort study sought to characterize the clinical course, vascular and hydrocephalic complications, and short- and long-term functional outcomes of patients with aneurysmal-pattern anSAH relative to those with perimesencephalic-pattern anSAH and aSAH.

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The study included 99 patients with anSAH, including aneurysmal-pattern anSAH (n=33) and perimesencephalic-pattern anSAH (n=66), and a comparison group of 464 patients with aSAH. All participants were treated in the neurointensive care unit at the Mayo Clinic, Rochester, Minnesota, between January 2006 and April 2018. Outcomes included the presence of delayed cerebral ischemia, radiographic infarction, radiographic vasospasm, the need for CSF diversion or a ventriculoperitoneal shunt, and modified Rankin Scale scores within 1 year of ictus and at last clinical follow up.

Frequency of radiographic vasospasm was higher in patients with aneurysmal-pattern anSAH (45.5%) versus patients with perimesencephalic-pattern anSAH (24.2%) and was comparable to patients with aSAH. Rates of delayed cerebral ischemia and radiologic infarction were similar between aneurysmal- and perimesencephalic-pattern anSAH but were significantly lower compared with aSAH rates (P =.003 and P ≤.018). Patients with aneurysmal-pattern anSAH were more likely to require temporary CSF diversion and a ventriculoperitoneal shunt than patients with perimesencephalic-pattern anSAH (P ≤.03), but they shared a similar need for CSF drainage from hydrocephalus as patients with aSAH. However, patients with aneurysmal-pattern anSAH were significantly less likely to report poor functional outcomes within 1 year of ictus (odds ratio 0.26; 95% CI, 0.090-0.75) and at last follow up (hazard ratio 0.3; 95% CI, 0.19-0.49; P =.002) compared with patients with aSAH.

Limitations to the study included heterogeneity in patient age, time to last clinical follow up, and radiographic follow up between groups. Variation of definitions used for inclusion criteria may have restricted the study to patients who had a more distinctive clinical course or who were symptomatic enough to require some form of drainage, excluding patients who were asymptomatic or had mildly symptomatic hydrocephalus in routine imaging.

Whereas patients with aneurysmal-pattern anSAH presented with more severe symptoms and had higher complication rates than patients with perimesencephalic-pattern anSAH, overall patients with anSAH had better clinical outcomes than patients with ruptured cerebral aneurysms.

Reference

Nesvick CL, Oushy S, Rinaldo L, Wijdicks EF, Lanzino G, Rabinstein AA. Clinical complications and outcomes of angiographically negative subarachnoid hemorrhage [published online April 17, 2019]. Neurology. doi:10.1212/WNL.0000000000007501