Introduction Due to the risk of early rebleeding, current aneurysmal subarachnoid hemorrhage guidelines call for aneurysm repair as early as is feasible. Emergent overnight aneurysm repair is not currently the standard of care at most institutions. However, recent studies have suggested that 24-hour availability of emergent aneurysm repair may reduce the incidence of rebleeding. At our institution, aneurysmal subarachnoid hemorrhage patients who arrive overnight are typically managed in the Neurosurgical ICU (NICU) prior to definitive repair in the morning. Consequently, we sought to review our subarachnoid hemorrhage cases to determine if a protocol of 24-hour emergent aneurysm repair would reduce the rate of rebleeding.

Methods We retrospectively reviewed a prospectively collected database of all non-traumatic subarachnoid hemorrhage patients admitted to the University of Michigan between January 1, 2010 and April 1, 2014. Clinical characteristics including aneurysm size and location, Hunt-Hess grade, Modified Fisher score, and complications such as rebleeding were collected prospectively. Rebleeding was diagnosed by the presence of new or expanded hemorrhage on CT scan. Charts were reviewed for all patients with rebleeding to determine the timing of rebleeding and whether rebleeding may have been prevented by emergent overnight aneurysm repair.

Results Of 323 cases, 17 (5.3%) experienced rebleeding a median of 12 h after symptom onset. Of these, 1 may have been preventable by emergent aneurysm repair, a 0.3% reduction in the rate of rebleeding. Rebleeds were not preventable in the other 16 patients for the following reasons: 6 occurred prior to transfer to our institution; 2 occurred intraoperatively; 3 occurred during endovascular coiling; 2 had negative initial angiograms and subsequently rebled from presumed aneurysms; 1 experienced rebleeding several hours after attempted coiling of a giant basilar tip aneurysm; 1 had unsuccessful attempted coiling at an outside hospital and family declined definitive surgical intervention at our institution; and 1 had a fusiform basilar aneurysm that was not amenable to intervention. The patient whose rebleed was potentially preventable presented overnight with basal ganglia and intraventricular hemorrhage that was thought likely to be due to hypertension. She then experienced rebleeding several hours after arriving to the NICU and was found to have a left ICA aneurysm that was surgically clipped.

Discussion This retrospective case series suggests that the presence of a protocol of 24-hour emergent aneurysm repair could have resulted in a 0.3% reduction in our institution’s rate of rebleeding. Potential explanations for the small risk reduction include the large number of patients that are transferred to our institution, as well as improvements in the neurosurgical ICU management of patients with unsecured aneurysms. It is unclear if such a protocol would positively impact neurological outcomes. The risks of implementing 24-hour aneurysm repair include provider fatigue and decreased availability of experienced neurosurgical anesthesiologists and OR staff overnight. The cost-effectiveness of such an approach at our institution is also uncertain and requires further study. These findings suggest that studies showing a significant reduction in rebleeding by  emergency aneurysm treatment may not generalize to all institutions.

Disclosures C. Williamson: None. A. Pandey: None.