Predictors of Adverse Outcome in Patients Treated for Low-Grade Aneurysmal Subarachnoid Hemorrhage: A Cohort Study

Objectives: To evaluate the correlation between demographic, clinical, radiological and treatment-related variables and functional outcome 1 year after the event in patients presenting with low-grade aneurysmal SAH.

Methods: We retrospectively reviewed clinical, morphological and treatment-related characteristics in patients treated in our institution with a diagnosis of low-grade (i.e., WFNS grade I-III) aneurysmal SAH over an 11 year-period. Univariate and multivariate regression models were used to test the association between poor functional outcome (i.e., neurological deterioration leading to a mRS>2, including death) at 1 year and the following characteristics: gender, age, history of smoking, WFNS grade, cardiopulmonary arrest prior to treatment, posterior circulation aneurysm location, maximum aneurysm diameter superior than 7 mm, associated intraparenchymal hematoma, associated acute hydrocephalus, Fisher SAH grade, early aneurysmal treatment (first 24 hours) and treatment modality (endovascular versus clipping).

Results: 212 consecutive cases were reviewed. 149 (70.3%) cases were women. Mean age at the time of SAH diagnosis was 52.2 ± 14.7 years-old. WFNS grade at the time of admission was I in 120, II in 72 and III in 20 cases, respectively. Aneurysms were treated surgically in 142 (67%) and endovascularly in 70 (33%) cases. 50 (23.6%) cases presented with SAH-related acute hydrocephalus. 29 (13.7%, 95%CI: 9.7-19.0) cases experienced a neurological deterioration leading to a modified Rankin score (mRS) > 2 at 1 year, including 16 (7.5%, 95%CI: 4.6-12.0) cases of mortality. In multivariate analysis, acute hydrocephalus (OR 4.8; 95%CI: 2.0-11.3) and WFNS grade at the time of admission (OR 2.0; 95%CI: 1.1-3.7) were the only independent characteristics significantly associated with poor functional outcome.

Conclusion: Acute hydrocephalus is a strong independent risk factor for development of poor functional outcome following treatment for aneurysmal low-grade SAH. Prompt cerebrospinal fluid flow diversion strategies should be considered in patients experiencing SAH-related hydrocephalus, independent of their initial clinical presentation.