Michail Makris, Eleftheria Ztriva, Eleni Gavriilaki, Vasileios Patriarcheas, Vasiliki Gougoula, Michail Giannakakis, Alexandros Tselepis, Georgios Ntaios, Christos Savopoulos, Georgia Kaiafa
Background: Endothelial dysfunction is a key player in stroke pathophysiology. The Endothelial Activation and Stress Index (EASIX) is a biomarker of endothelial injury validated in hematology, sepsis, and cardiovascular cohorts; however, its prognostic role in stroke remains unclear. This retrospective cohort study aims to provide preliminary evidence on the potential utility of EASIX levels as a biomarker for assessing stroke severity and predicting outcomes. Methods: We retrospectively studied 100 patients aged ≥ 18 years admitted with acute ischemic stroke (AIS) or transient ischemic attack (TIA) between January 2020 and July 2024. EASIX was calculated on admission as LDH × creatinine/platelets. Outcomes included in-hospital and 12-month mortality, stroke severity assessed by the NIHSS score, and disability assessed as a modified Rankin score (mRS). Results: Median age was 82 years; 56% were female. The in-hospital and 12-month mortality rates were 47.9% in patients with AIS and 17.2% in patients with TIA, respectively. Overall, EASIX was not associated with NIHSS, mRS, or mortality in the total cohort. Ιn the subgroup of patients with small vessel disease (n = 10), higher EASIX was associated with worse mRS at 12 months (β = 2.383, p = 0.02) and increased mortality (β = 0.653, p = 0.02). EASIX correlated positively with WBC (p < 0.001) and CRP (p = 0.01). Female sex was associated with lower EASIX values. Conclusions: EASIX was not associated with outcomes in the overall AIS/TIA cohort, but it demonstrated potential prognostic relevance in small vessel disease (SVD), which has not been reported previously in the literature. Further prospective research is warranted to validate the potential association between systemic endothelial stress and small vessel disease before the implementation of EASIX as a prognostic tool in patients with stroke due to SVD.