Introduction: Since the publication of the International Subarachnoid Aneurysm Trial (ISAT) in 2002, endovascular treatment has been increasingly preferred to open surgical clipping for a majority of ruptured aneurysms1-4. Although subsequent studies have supported the role of endovascular therapy for ruptured aneurysms, many questions remain, including the effect of treatment modality on secondary outcomes such as shunt dependency. Here, we review data from the Nationwide Inpatient Sample to assess rates of cerebrospinal fluid (CSF) diversion following subarachnoid hemorrhage (SAH) treatment and evaluate outcomes in a dataset representing current, broad clinical practice.

Methods: Data were extracted from the 2004-2014 Nationwide Inpatient Sample from all patients who underwent endovascular aneurysm treatment (International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure codes 39.72, 39.75, 39.76, and 88.41) or aneurysm clipping (39.51). Within this group, patients who underwent a CSF diversion procedure were identified using the ICD-9-CM procedure code 02.3x. Weighted survey counts of the two groups were used to compare mortality in this population.

Results: There was no difference in rates of CSF diversion between the endovascular and open surgical treatment groups (15.06% for surgical vs. 14.93% endovascular; p=0.56). However, among patients who required CSF diversion, those managed endovascularly had a higher mortality (7.46% endovascular vs 5.69% surgical; Odds Ratio 1.33, 95% CI 1.16-1.56, p<0.0001).

Conclusions: Although the proportion of patients undergoing CSF diversion was similar between open and endovascular treatment groups, we found that the mortality rates in those patients with shunt-dependent hydrocephalus was significantly higher in the endovascular cohort as compared to the group managed surgically. This may help direct treatment for SAH patients, especially if their initial presentation includes acute hydrocephalus for which a shunt may be required long term. Future directions include time trend analysis of mortality with regards to treatment modality.

Patient Care: The outcomes of this study may help guide future neurosurgeons when they are choosing to treat SAH patients with surgery versus endovascular coiling – especially in the setting of acute hydrocephalus.

Learning Objectives: Mortality rates in shunt-dependent hydrocephalus are increased in SAH patients treated with endovascular coiling.

References: 1. Molyneux, Andrew. International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised trial. The Lancet , Volume 360 , Issue 9342 , 1267 – 1274. 2. Thomas, Ajith J et al. ISAT: equipoise in treatment of ruptured cerebral aneurysms? The Lancet , Volume 385 , Issue 9969 , 666 – 668. 3. E.G. Klompenhouwer, J.T.A. Dings, R.J. van Oostenbrugge, S. Oei, J.T. Wilmink and W.H. van Zwam. Single-Center Experience of Surgical and Endovascular Treatment of Ruptured Intracranial Aneurysms. American Journal of Neuroradiology March 2011, 32 (3) 570-575. 4. Laurent Pierot, MD, PhD; Ajay K. Wakhloo, MD, PhD. Endovascular Treatment of Intracranial Aneurysms Current Status. Stroke. 2013;44:2046-2054.