Angiogram-negative subarachnoid hemorrhage: relationship between bleeding pattern and clinical outcome

Area of Science:

• Neurology
• Neurosurgery
• Radiology

Background:

• Angiogram-negative subarachnoid hemorrhage (anSAH) constitutes 15% of spontaneous SAH cases.
• Emerging evidence suggests that the diagnostic yield and patient outcomes in anSAH vary based on the initial bleeding pattern observed.
• This study details a single-center's experience managing SAH patients with initially negative digital-subtracted angiograms (DSA).

Purpose of the Study:

• To analyze the diagnostic yield, in-hospital complications, and clinical outcomes in patients with anSAH.
• To investigate the correlation between initial bleeding patterns on CT and patient outcomes.
• To determine the incidence of true aneurysms in the anSAH population.

Main Methods:

• A retrospective review of anSAH patients was conducted.
• Bleeding patterns were categorized using computed tomography (CT) as perimesencephalic (PMN), diffuse, cortical, or xanthochromia.
• Diagnostic yield, complications, and outcomes were analyzed, including additional imaging and interventions.

Main Results:

• Of 68 anSAH patients, 39.7% had PMN SAH, 48.5% diffuse SAH, 8.8% cortical SAH, and 2.9% xanthochromia.
• A structural bleeding cause was identified in 8.8% of patients, with two aneurysms (2.9%) found in those with diffuse SAH.
• Older age and diffuse bleeding patterns were significant predictors of unfavorable outcomes (mRS 3-6).
• 42.6% experienced medical complications, often treatment-related for non-diffuse patterns.

Conclusions:

• The incidence of aneurysms in anSAH is low at 2.9%.
• The initial bleeding pattern significantly influences diagnostic yield and clinical outcomes.
• Diffuse bleeding patterns correlate with higher diagnostic yield, increased complications, and worse outcomes compared to other patterns.