Systemic Inflammatory Response in Spontaneous Subarachnoid Hemorrhage from Aneurysmal Rupture versus Subarachnoid Hemorrhage of Unknown Origin

A Mediation Analysis of the Association Between Systemic Inflammation Response Index, in-Hospital Complications, and Poor Long-Term Functional Outcomes in Patients with Aneurysmal Subarachnoid Hemorrhage: Insights from a Large Prospective Cohort Study

Purpose

Early systemic inflammatory changes are increasingly recognized as factors influencing outcomes after aneurysmal subarachnoid hemorrhage (aSAH). Systemic inflammation response index (SIRI), an inflammation biomarker, was thought to be associated with adverse outcomes in many other diseases. However, in aSAH, research on SIRI remains limited. Thus, our objective was to investigate the association between SIRI and poor long-term functional outcomes while evaluating the mediating role of in-hospital complications in this association.

Patients and Methods

SIRI was defined as neutrophil count × monocyte count/lymphocyte count. Patients were categorized according to SIRI quartiles. Stabilized inverse probability of treatment weighting (sIPTW) was utilized to minimize group differences. The association between SIRI and in-hospital complications as well as poor 90-day functional outcomes (mRS 3-6) was estimated by multivariable logistic regression analyses. Mediation analysis was performed to investigate the relationship between SIRI and poor functional outcomes mediated by in-hospital complications.

Results

A total of 650 patients were prospectively included. After sIPTW, compared to the lowest quartile, an elevated SIRI was associated with delayed cerebral ischemia (DCI) (OR 2.12, 95% CI 1.20-3.74), post-operative pneumonia (POP) (OR 2.16, 95% CI 1.29-3.62) and poor 90-day functional outcomes (OR 3.03, 95% CI 1.55-5.91). In-hospital complications including DCI (mediation proportion, 18.18% before sIPTW and 20.0% after sIPTW) and POP (mediation proportion, 18.18% before sIPTW and 26.7% after sIPTW) partially mediated the association between SIRI and poor 90-day functional outcomes. Mediation analysis yielded comparable results in subgroups stratified by age and sex.

Conclusion

In this study, SIRI was associated with poor long-term functional outcomes in aSAH, which was partially mediated by DCI and POP with a mediation proportion exceeding 18%. Our findings might underscore the potential utility of SIRI in prompting physicians to address systemic inflammatory status timely to prevent in-hospital complications, including DCI and POP, and ultimately improve long-term functional outcomes.

HDL anti-inflammatory function is impaired and associated with high SAA1 and low APOA4 levels in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease with high morbidity and mortality rates. Within 24 hours after aSAH, monocytes are recruited and enter the subarachnoid space, where they mature into macrophages, increasing the inflammatory response and contributing, along with other factors, to delayed neurological dysfunction and poor outcomes. High-density lipoproteins (HDL) are lipid-protein complexes that exert anti-inflammatory effects but under pathological conditions undergo structural alterations that have been associated with loss of functionality. Plasma HDL were isolated from patients with aSAH and analyzed for their anti-inflammatory activity and protein composition. HDL isolated from patients lost the ability to prevent VCAM-1 expression in endothelial cells (HUVEC) and subsequent adhesion of THP-1 monocytes to the endothelium. Proteomic analysis showed that HDL particles from patients had an altered composition compared to those of healthy subjects. We confirmed by western blot that low levels of apolipoprotein A4 (APOA4) and high of serum amyloid A1 (SAA1) in HDL were associated with the lack of anti-inflammatory function observed in aSAH. Our results indicate that the study of HDL in the pathophysiology of aSAH is needed, and functional HDL supplementation could be considered a novel therapeutic approach to the treatment of the inflammatory response after aSAH.

A prospective cohort study on decreased serum apelin-13 levels after human aneurysmal subarachnoid hemorrhage: associations with severity and prognosis

Apelin-13 may have neuroprotective effects. We aimed to determine whether serum apelin-13 could serve as a potential biomarker for severity, delayed cerebral ischemia (DCI), and prognosis after human aneurysmal subarachnoid hemorrhage (aSAH). In this prospective, observational, cohort, single-center study of 139 patients with aSAH and 139 healthy individuals, serum apelin-13 levels were determined. The indicators of stroke severity were the Hunt-Hess scale and the modified Fisher grading scale. The prognostic parameters were DCI and 6-month worse prognosis (Extended Glasgow Outcome Scale scores of 1-4). Using binary logistic regression analysis, the relationship between serum apelin-13 levels and prognosis was reported as odds ratios (ORs) with 95% confidence intervals (CIs). Under the receiver operating characteristic curve, prognostic abilities were shown as areas under the curve (AUCs) with 95% CIs. Serum apelin-13 levels were substantially lower in patients than in controls (median, 28.8 versus 48.6 ng/ml; P < 0.001), in patients with DCI than in non-DCI patients (median, 14.9 versus 31.6 ng/ml; P < 0.001), and in patients with worse prognosis than in those with good prognosis (median, 16.3 versus 33.7 ng/ml; P < 0.001). Serum apelin-13 levels were independently correlated with Hunt-Hess scores (beta, -6.836; 95% CI, -8.963-4.708; VIF, 2.219; P = 0.001) and modified Fisher scores (beta, -3.350; 95% CI, -6.151-0.549; VIF, 1.562; P = 0.019). Serum apelin-13 levels were an independent predictor of DCI (OR, 0.951; 95% CI, 0.914-0.990; P = 0.022) and worse prognosis (OR, 0.954; 95% CI, 0.916-0.993; P = 0.013). Serum apelin-13 levels significantly differentiated DCI and poor prognosis, with AUCs of 0.753 (95% CI, 0.656-0.850) and 0.791 (95% CI, 0.713-0.868) respectively. Using the Youden method, serum apelin-13 levels < 19.3 ng/ml distinguished the risk of DCI with 64.7% sensitivity and 77.1% specificity, and serum apelin-13 levels < 30.2 ng/ml discriminated the development of worse prognosis with 89.1% sensitivity and 63.4% specificity. Serum apelin-13 levels combined with Hunt-Hess scores and modified Fisher scores displayed a significantly higher AUC than any one of them for prognostic prediction (all P < 0.05). Decreased serum apelin-13 levels, which are strongly correlated with disease severity, independently predicted poor outcomes following aSAH, substantializing serum apelin-13 as a useful prognostic biomarker of aSAH.

Inflammatory Burden Index: Association Between Novel Systemic Inflammatory Biomarkers and Prognosis as Well as in-Hospital Complications of Patients with Aneurysmal Subarachnoid Hemorrhage

Purpose

Systemic inflammation plays an important role in the pathophysiology and progression of aneurysmal subarachnoid hemorrhage (aSAH). In this study, we aimed to investigate the association between a new biomarker, the inflammatory burden index (IBI) and the prognosis as well as in-hospital complications of aSAH patients.

Patients and Methods

We analyzed data from patients with aSAH between January 2019 and September 2022 who were included in the LongTEAM (Long-term Prognosis of Emergency Aneurysmal Subarachnoid Hemorrhage) registry study. The IBI was formulated as C-reactive protein × neutrophils/lymphocytes. The unfavorable functional prognosis was assessed by the modified Rankin Scale (mRS). Receiver operating characteristic (ROC) curve analysis was conducted to determine the optimal cut-off values for IBI to distinguish the unfavorable functional prognosis. Multivariate logistic regression was applied to investigate the association between IBI and in-hospital complications. Propensity score matching was adjusted for imbalances in baseline characteristics to assess the effect of IBI on prognosis.

Results

A total of 408 consecutive patients with aSAH enrolled in the study, of which 235 (57.6%) were female patients and the mean age was 55.28 years old. An IBI equal to 138.03 was identified as the best cut-off threshold to distinguish the unfavorable prognosis at 3 months (area under the curve [AUC] [95% CI] 0.637 [0.568-0.706]). ln IBI was independently associated with 3-month functional prognosis (OR [95% CI] 1.362 [1.148-1.615]; P<0.001), pneumonia (OR [95% CI] 1.427 [1.227-1.659]; P<0.001) and deep venous thrombosis (DVT). (OR [95% CI] 1.326 [1.124-1.564]; P=0.001). After propensity score matching (57:57), an increased proportion of patients with IBI ≥138.03 had a poor functional prognosis at 3 months and in-hospital complications including developed pneumonia and DVT.

Conclusion

In patients with aSAH, high IBI level at admission was associated with unfavorable functional prognosis as well as pneumonia and deep vein thrombosis.