High cystatin C levels predict long‐term mortality in patients with ST‐segment elevation myocardial infarction undergoing late percutaneous coronary intervention: A retrospective study

OBJECTIVES: Late percutaneous coronary intervention (PCI) in patients with ST‐segment elevation myocardial infarction (STEMI), defined as time of PCI > 7 days from symptom onset, is a common practice with clinical benefits. This study aimed to evaluate the predictive value of admission cystatin C (cys C) level on long‐term mortality in STEMI patients receiving late PCI. METHODS: Medical records of STEMI patients who were hospitalized between 2009 and 2011 from eight PCI‐capable hospitals in Northwest China were retrospectively analyzed. Cys C level ≥ 1.105 mg/L was considered as the best predictor of long‐term mortality based on the receiver‐operating characteristic analysis. Patients were followed up by phone or face‐to‐face interviews, and the long‐term mortality was obtained by reviewing medical records. RESULTS: The final analysis included 716 STEMI patients who received late PCI and had available cys C levels prior to PCI, and 524 were assigned into the high cys C group and 192 the low cys C group. Patients were followed up for an average length of 40.37 months. Compared with the low cys C group, the high cys C group had a higher long‐term all‐cause mortality (10.4% vs 2.9%, P < 0.001) and a higher cardiac mortality (6.8% vs 2.1%, P = 0.004). Multivariate Cox regression analysis showed that high cys C level was an independent predictor for both long‐term all‐cause mortality and cardiac mortality. CONCLUSIONS: High cys C level at admission is an independent predictor of long‐term mortality in STEMI patients undergoing late PCI.