Evidence Hub

Haemorrhage pattern and clinical outcomes after angiogram negative subarachnoid haemorrhage: a systematic review and meta analysis

Munasinghe T, Senanayake H, Arulshankar S, Slater LA, Lai L

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2026

5,921 participants

Abstract

BACKGROUND: Angiogram-negative subarachnoid haemorrhage accounts for approximately 15% of spontaneous subarachnoid haemorrhage, yet surveillance practices and the role of repeat vascular imaging remain inconsistent. The extent to which haemorrhage pattern predicts clinical complications and delayed vascular lesion detection is uncertain.

METHODS: We conducted a systematic review and meta-analysis in accordance with PRISMA guidelines. Studies reporting clinical outcomes in angiogram-negative subarachnoid haemorrhage were included. Outcomes were pooled using random-effects generalised linear mixed models and stratified by haemorrhage pattern, including perimesencephalic, non-perimesencephalic, diffuse, and convexity haemorrhage.

RESULTS: Sixty-seven studies comprising 5,921 patients were included. Favourable functional outcome at 3-6 months occurred in 95-97% of patients across all haemorrhage patterns. Rebleeding was uncommon, occurring in 1% of perimesencephalic, 2% of non-perimesencephalic, and 3% of diffuse haemorrhage. Clinical vasospasm occurred in 3%, 11%, and 13%, respectively, while acute hydrocephalus requiring external ventricular drainage occurred in 7%, 29%, and 44%. Among studies reporting repeat vascular imaging, 82 vascular lesions were identified, predominantly in non-perimesencephalic haemorrhage. No lesions were detected on imaging performed within 7 days of ictus; all reported lesions were identified at or beyond 7 days, although repeat imaging was…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 5,921 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free