Clinical prognostic significance of plasma cystatin C levels among patients with acute coronary syndrome.

BACKGROUND

This article aims to investigate the changes of plasma cystatin C concentration (PcyC), and to evaluate the relationship between PcyC and acute coronary syndrome.

METHODS

A total of 126 consecutive patients with coronary artery disease (CAD) were enrolled in this study, consisting of 34 patients with stable angina pectoris (SAP), 56 patients with unstable angina pectoris (UAP), 36 patients with acute myocardial infarction (AMI), and 34 healthy subjects as controls. Plasma cystatin C, high sensitivity C-reactive protein (hs-CRP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and uric acid (UA) in all subjects were determined. All patients were followed up for 6 months and adverse cardiovascular events were recorded.

RESULTS

Plasma cystatin C was elevated in CAD. Cystatin C levels were significantly higher in UAP patients than those in SAP patients and controls (2013.83 +/- 633.85 ng/mL vs 1348.41 +/- 369.62 ng/mL and 1509.99 +/- 408.65 ng/mL, P < 0.05), but were much lower than those in AMI patients (2013.83 +/- 633.85 ng/mL vs 2873.55 +/- 1149.48 ng/mL, P < 0.05). Patients with AMI also exhibited significantly higher cystatin C levels than SAP patients and the control group (2873.55 +/- 1149.48 ng/mL vs 1348.41 +/- 369.62 ng/mL and 1509.99 +/- 408.65 ng/mL, P < 0.01). Much higher hs-CRP concentrations were found in UAP patients (1.58 +/- 2.81 mg/L, P < 0.05) and AMI patients (20.68 +/- 18.98 mg/L, P < 0.01). Cystatin C was positively and significantly correlated with age, hs-CRP, white blood cells (WBC), creatinine, and UA (r > 0, P < 0.05), whereas a significantly negative correlation was observed with HDL-C (r = - 0.227, P < 0.05). These coefficients were clearly high for creatinine (r = + 0.612) and WBC (r = + 0.459). During the 6 month follow-up, 26 patients were found with adverse cardiovascular events and had significantly higher cystatin C levels than the 22 control patients at admission (2356.73 +/- 897.64 ng/mL vs 1469.51 +/- 574.83 ng/mL, P < 0.01).

CONCLUSIONS

Cystatin C plays an important role in the development of CAD and PcyC is a strong predictor for risk of cardiovascular events.