Correlation between CVS and SII in Aneurysmal Subarachnoid Hemorrhage and Construction of Risk Assessment System

This study aimed to investigate the correlation between cerebral vasospasm (CVS) and systemic im-mune-inflammation index (SII) in aneurysmal subarachnoid hemorrhage (aSAH) patients and to construct a risk assessment system based on SII.

This study included 230 eligible patients with aSAH from June 1, 2021, through December 30, 2024. By retrospective analysis method, clinical information and laboratory data of the patients were collected. Patients were divided into two groups: those with CVS (CVS+) and those without CVS (CVS-). The clinical characteristics of patients were compared, and the correlation between SII index and CVS was analyzed. The risk assessment system was constructed using a Cox regression model, which analyzed independent variables with significant differences.

Age of CVS+ patients was significantly higher than that of CVS- patients. The CVS+ group exhibited higher proportions of patients with medium-sized aneurysms, more severe CT imaging features of hemorrhage, increased electrolyte disturbances, and elevated immune system markers compared to the CVS- group. The median time for CVS onset was 7.5 days when SII was at least 1.58, considerably shorter than the 16 days for SII less than 0.64 and 15 days for SII between 0.64 and 0.93 (p < 0.0001). When the SII index was elevated, the risk of CVS increased. The SII-based risk assessment system reduced the significance of age and modified Fisher grade in endpoint event prediction, while increasing the overall predictive value of the model.

This study revealed a significant correlation between CVS and SII index in aSAH patients and successfully constructed a risk assessment system based on SII. This system can more accurately predict the risk of CVS in aSAH patients and provides an important reference for clinical decision-making.