Prognostic value of serum cystatin C and its changes in patients with ST-segment elevation myocardial infarction.

Background: Serum cystatin C (Cys-C) has been established as a prognostic marker in various cardiovascular settings, but its changes and their relationship with long-term outcomes in ST-segment elevation myocardial infarction (STEMI) patients remain underexplored. Therefore, this study aims to evaluate the prognostic value of serum Cys-C concentration and its changes in predicting all-cause mortality in STEMI patients with normal or mildly impaired renal function. Methods: This single-center, retrospective observational study enrolled 753 STEMI patients who underwent emergency percutaneous coronary intervention between February 2019 and December 2024. Serum Cys-C levels were measured at baseline and the last measurement. Patients were categorized into tertiles based on baseline Cys-C, follow-up Cys-C, and the absolute change in Cys-C. The primary endpoint was all-cause mortality. Results: During follow-up of 627 days, 75 deaths occurred. Non-survivors had significantly higher baseline and follow-up Cys-C levels, as well as greater absolute increases in Cys-C, compared to survivors (all Conclusion: Elevated serum Cys-C levels at baseline and the last measurement, as well as an increase in Cys-C over time, are independently associated with higher all-cause mortality in STEMI patients. Serial measurement of Cys-C may enhance risk stratification and serve as a dynamic indicator for monitoring disease progression and treatment response.