Risk Factors for Shunt Dependency after Aneurysmal Subarachnoid Hemorrhage: A Meta-Analysis including 25 Years of Data

Object: Aneurysmal subarachnoid hemorrhage (aSAH) may be complicated by hydrocephalus in 6·5% to 67% of cases. 8–63% of hydrocephalic patients with aSAH develop shunt dependency, which is often managed by ventriculoperitoneal shunt placement. Our objective was to review all published literature regarding risk factors for shunt dependency in patients with aSAH and calculate the magnitude of each risk factor to better guide patient management.

Methods: We searched PubMed and MEDLINE for level A and level B articles published through December 31, 2014 that described factors affecting shunt dependency after aSAH, and performed a systematic review and meta-analysis, stratifying the existing data according to level of evidence.

Results: Based on the results of the meta-analysis, risk factors for shunt dependency include high Fisher grade (OR 7·74, 95% CI 4·47–13·41), acute hydrocephalus (OR 5·67, 95% CI 3·96–8·12), in-hospital complications (meningitis, pneumonia, vasospasm, or ischemic stroke; OR 4·91, 95% CI 2·79–8·64), presence of intraventricular blood (OR 3·93, 95% CI 2·80–5·52), high Hunt and Hess grade (OR 3·25, 95% CI 2·51–4·21), rehemorrhage (OR 2·21, 95% CI 1·24–3·95), posterior circulation aneurysm location (OR 1·85, 95% CI 1·35–2·53), and age ≥60 years (OR 1·81, 95% CI 1·50–2·19). The only risk factor included in our meta-analysis that did not reach statistical significance was female sex (OR 1·13, 95% CI 0·77–1·65).

Conclusions: We used highly powered data to identify several risk factors for shunt dependency in aSAH patients that help predict which patients are likely to require permanent shunting. Although some of these risk factors are not independent of each other, this information assists clinicians in identifying at-risk patients and managing their treatment without adding additional cost to current standards of care.