Association between Endothelial Activation and Stress Index and mortality in coronary heart disease ICU patients: A retrospective cohort study

Background: Coronary heart disease (CHD) is a major cause of mortality in critically ill patients, with endothelial dysfunction playing a pivotal role in disease progression. The Endothelial Activation and Stress Index (EASIX), a composite biomarker reflecting endothelial injury and systemic stress, has demonstrated prognostic value across various cardiovascular conditions. Nevertheless, the association of this phenomenon with mortality in CHD patients requiring intensive care remains to be elucidated. Methods A retrospective cohort study was conducted using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The study encompassed a total of 2,469 critically ill CHD patients, who were stratified into tertiles based on admission EASIX scores. The application of Cox proportional hazard models and restricted cubic spline regression was utilised for the purpose of evaluating the association between EASIX and all-cause mortality within a 30-day, 90-day and 365-day timeframe. Subgroup analyses were performed in order to assess potential effect modifications. Results The median age of the cohort was found to be 73 years (interquartile range: 64–81 years), with 66.13% of subjects being male (1632/2468). Patients in the highest EASIX tertile exhibited significantly elevated 30-day mortality (34.87% vs. 10.45%, p<0.001) and 365-day mortality (38.88% vs. 12.15%, p<0.001) compared to the lowest tertile. Cox regression analysis revealed EASIX to be an independent predictor of 30-day mortality (adjusted hazard ratio [HR]: 2.237; 95% confidence interval [CI]: 1.534-3.262; p < 0.001) and 365-day mortality (adjusted HR: 2.204; 95% CI: 1.553-3.129; p < 0.001) following comprehensive adjustment for confounders. The Kaplan-Meier analysis demonstrated a significantly inferior survival probability in the highest EASIX stratum (log-rank p<0.0001). The restricted cubic spline analysis indicated a near-linear dose-response relationship between EASIX and mortality risk (p for non-linearity < 0.05). Conclusion Elevated EASIX scores have been shown to independently correlate with increased short and long-term mortality in critically ill CHD patients, suggesting its utility as a novel prognostic biomarker for risk stratification in this high-risk population. Further prospective validation and investigation of therapeutic implications are warranted. Clinical trial number Not applicable.