Platelet factor 4 and stromal cell-derived factor are novel prognostic biomarkers for cerebral vasospasm and mortality after subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition associated with high rates of morbidity and mortality, mainly due to post-hemorrhagic complications such as cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI). Recent evidence implicates platelet activation and inflammatory mediators in the cascade of secondary injury following aSAH. Monitoring and timely treatment of post-SAH complications is critical to improve clinical outcomes. Current methods of radiological diagnostic for monitoring are laborious and bound to multiple risks, including radiation exposure. Point-of-care blood biomarkers early after SAH are urgently needed to timely detect and treat post-SAH complications. This prospectively designed cohort study aimed to search for novel predictive biomarkers for vasospasm and clinical outcome with overarching goal to improve treatment decision during intensive care treatment. In this prospective study conducted from 2020 to 2022, 63 aSAH patients (16 male and 47 female) were enrolled. Blood samples were collected to measure platelet factor 4 (PF4) and stromal cell derived factor (SDF) levels. To detect vasospasm, computed tomography (CT) perfusions at day 0, 4, 7 and 11 after the SAH was performed and mean transient time (MTT) was quantified as a measure of cerebral perfusion. Clinical outcome was analysed using modified rankin scale (mRS). Clinical and radiological data was recorded prospectively. The association between PF4 levels and CVS was assessed using receiver operating characteristic (ROC) curve analysis and logistic regression, while linear regression analyses were performed to examine the correlations of PF4 with mean transit times (MTT) and of SDF with the day of death among non-survivors. Logistic regression revealed that each 1 ng/mL increase in PF4 was associated with a 38% increase in the odds of developing CVS (OR = 1.38; 95% CI: 1.07-1.79; p = 0.01). Moreover, elevated PF4 levels were significantly correlated with longer MTT (β = 0.107 per ng/mL; 95% CI: 0.02-0.19; p = 0.02), suggesting impaired cerebral perfusion. Additionally, among non-surviving patients, higher SDF levels were significantly associated with a later occurrence of death (β = 0.01 per pg/mL; 95% CI: 0.001-0.019; p = 0.03). The findings indicate that PF4 and SDF are promising biomarkers in aSAH. Elevated PF4 levels are associated with an increased risk of CVS and impaired cerebral perfusion, while higher SDF levels correlate with mortality. These biomarkers may offer valuable insights for early risk stratification and pave the way for targeted therapeutic interventions in patients with aSAH.