Cystatin C as prognostic biomarker in ST-segment elevation acute myocardial infarction

Cystatin C is a marker of renal dysfunction, and preliminary studies have suggested it might have a role as a prognostic marker in patients with coronary artery disease. The aim of the present study was to evaluate the usefulness of cystatin C for risk stratification of patients with ST-segment elevation myocardial infarction, regarding in-hospital and long-term outcomes. We included 153 consecutive patients with ST-segment elevation myocardial infarction treated by primary angioplasty. The baseline cystatin C level was measured at coronary angiography. The in-hospital outcome was determined as progression to cardiogenic shock or in-hospital death, and the long-term outcome was assessed, considering the following end points: (1) death and (2) death or reinfarction. Of the 153 patients evaluated (age 61 ± 12 years; 75.6% men), 15 (14.4%) progressed to cardiogenic shock and 4 (2.7%) died during hospitalization. The patients who progressed to cardiogenic shock or died during hospitalization had significantly greater cystatin C levels (1.02 ± 0.44 vs 0.69 ± 0.24 mg/L; p = 0.001). Long-term follow-up was available for 130 patients (583 ± 163 days). Among them, 11 patients died and 7 had reinfarction. A high baseline cystatin C level was associated with an increased risk of death (hazard ratio 8.5; p = 0.009) and death or reinfarction (hazard ratio 3.89; p = 0.021). Furthermore, only high baseline cystatin C levels and left ventricular ejection fraction ≤40% were independent predictors of the long-term risk of death, with synergistic interaction between the 2. In conclusion, cystatin C is a new biomarker with significant added prognostic value for patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention, predicting both short- and long-term outcomes.