Abstract
BACKGROUND: Early identification of high-risk patients presenting with ST-segment elevation myocardial infarction (STEMI) helps prevent complications. The shock index (SI) is a bedside risk-stratification tool used in emergency departments. In this study, we aimed to assess the SI's predictive value for prognosticating in-hospital and one-year mortality, as well as one-year major cardiovascular events (MACEs). As secondary endpoints, we assessed the age SI's performance and the influence of prehospital transport factors on SI's predictive value. METHODS: This prospective cohort study is named SEMI-CI and enrolled patients with STEMI who were referred to a cardiology hospital in Isfahan. We analyzed data on 867 patients with STEMI. Systolic blood pressure (SBP) and heart rate (HR) upon admission were used to calculate SI. Patients were divided into two groups based on SI, and 277 patients had SI > 0.7. RESULTS: In-hospital death, one-year mortality, and MACE were more prevalent in those patients presenting with SI ≥ 0.7. However, after multivariate adjustment, SI was an independent predictor of in-hospital mortality and MACE, but it was not associated with one-year mortality. Furthermore, mortality rates increased from lower to higher age groups. Among patients transferred by emergency medical services to our hospital, SI showed prognostic implications for in-hospital mortality but not for one-year mortality. CONCLUSIONS: The current study showed that a positive SI and age SI are valuable risk-stratification tools to identify high-risk patients presenting with STEMI.