Patient selection
We retrospectively reviewed prospectively collected data regarding intracerebral aneurysms from a single institution’s database. In total, 196 consecutive patients were diagnosed with aSAH between January 2014 and March 2018 (Fig. 1). The inclusion criteria of this study were as follows: (1) SAH was caused by the rupture of intracerebral aneurysm; (2) aSAH was accompanied by IVH at the time of diagnosis; (3) the ruptured aneurysm was treated either by microsurgery or by an endovascular method; (4) follow-up brain computed tomography (CT) was performed within 7 days to assess the IVH CCR and; (5) modified Rankins Scale (mRS) score at 3 months after discharge was identifiable via medical records. The exclusion criteria were as follows: (1) patients with any history of stroke that may affect the prognosis of aSAH other than IVH, such as a history of treatment for a ruptured or unruptured aneurysm, or a history of ischemic stroke; (2) patients presenting with any stroke-related lesion that may affect the prognosis of aSAH other than IVH, such as intracerebral hemorrhage, cerebral infarction, or vascular malformation; (3) patients who died within 7 days of admission, and; (4) patients with clinical deterioration due to rebleeding of the aneurysm. Intraventricular hemorrhage was confirmed in 80 of 173 patients, and 23 patients did not undergo follow-up CT within 7 days of aneurysmal rupture. After excluding 13 patients according to the exclusion criteria, 67 patients were finally included in the study.
Demographic, clinical, and radiographic data of the patients were collected based on electrical medical records, and data obtained from the aneurysm database were reviewed and compared for each group. The clinical condition on admission was graded according to the Hunt and Hess (H-H) grading system and radiologic condition on admission was assessed by SAH thickness on initial CT. The main outcome variable was the mRS score at 3-month follow-up, which was dichotomized between mRS scores of 0–2 and 3–6. The included patients were divided into two groups according to the mRS score at 3-month follow up (good outcome group, mRS score of 0–2 vs. poor outcome group, mRS score of 3–6). Delayed ischemic neurologic deficit (DIND), delayed infarction, and shunt-dependent hydrocephalus were investigated along with IVH CCR as prognostic factors for aSAH. Delayed ischemic neurologic deficit refers to symptomatic vasospasm that requires treatment identified by angiography, based on Kramer's criteria [1]. Delayed infarction was diagnosed if permanent cerebral infarction caused by DIND was confirmed by imaging. Shunt-dependent hydrocephalus was determined by clinical and radiologic signs of hydrocephalus which requires permanent CSF diversion within the follow-up period. This retrospective study was approved by the institutional review board of Severance hospital at Yonsei University College of Medicine (subject number: 4-2021-0828) and Bucheon St. Mary's hospital at the Catholic University of Korea (subject number: HC21RASI0072), and the requirement for informed consent was waived.
Treatment strategies for aneurysmal subarachnoid hemorrhage
All aSAH cases included in this study were treated according to the following protocol: (1) ruptured cerebral aneurysms were repaired within 48 hours by microsurgery or endovascular method; (2) the treatment plan was determined by multidisciplinary discussions among experienced neurosurgeons, neurointerventionists, and radiologists; (3) optimal medical treatment for preventing post-aSAH complications such as cerebral edema, vasospasm, and hydrocephalus were performed including close monitoring in intensive care units, administration of Nimodipine, and regular follow-up via transcranial doppler ultrasonography; (4) in case of acute hydrocephalus with clinical deterioration despite treatment, extraventricular drainage (EVD) was considered; (5) the EVD was maintained for up to two weeks, and if the EVD was intended to be maintained for more than two weeks, a change of EVD or permanent CSF diversion was considered contextually and; (6) the injection of intraventricular tissue plasminogen activator for the purpose of clot lysis was not considered.
Assessment of the clot clearance rate of intraventricular hemorrhage
The mGS was calculated by the method introduced by Morgan et al. [19]. The mGS incorporates IVH scores in relation to its anatomical extension. The maximum score of 32 indicates that every compartment is filled with blood and expanded. A score of 0 indicates no IVH. To evaluate the IVH CCR, initial and follow-up mGS was assessed by initial and 7-day follow-up brain CT, respectively. The IVH CCR was calculated as follows:
IVH CCR (%): [(initial mGS – follow up mGS) / initial mGS] x 100
All mGS values were measured by two independent investigators. If the measurements of the two investigators differed considerably, another neuroradiologist reviewed the data and a final consensus was reached by the three investigators regarding the results.
Statistical analysis
A univariate analysis was performed to determine the association of poor outcome with factors and characteristics associated to aSAH with IVH. The Student’s t-test was used for analyses of continuous variables and Pearson χ2 test was used for the analyses of categorical variables. Continuous variables were described as mean ± standard deviation (SD) and categorical variables were summarized as frequencies and percentages (%). A multivariate logistic regression analysis was performed for variables with an unadjusted effect, and p values <0.05 in the univariate analysis was used to determine independent associations between poor outcome and characteristics of aSAH with IVH. The threshold value for the cut-off point of the continuous variable among the outcome predictors for aSAH with IVH was determined using the receiver operating characteristics (ROC) analysis, and the diagnostic performance of the each variable was assessed. Pearson’s rank correlation coefficient was used to extrapolate the relationships between the continuous variable among the outcome predictors and IVH CCR. All p values <0.05 were considered statistically significant. All statistical analyses were performed using SPSS Statistics 23.0 (IBM Corp., Amonk, NY, USA).