Poster presentation | Open | Published:
Cystatin C in the prognostic stratification of patients with an acute coronary syndrome
Critical Carevolume 11, Article number: P246 (2007)
Early risk stratification is essential in the management of patients with an acute coronary syndrome (ACS). Measurements of renal function such as serum creatinine and estimation of creatinine clearance carry independent prognostic information in this population. Cystatin C is a new and better marker of renal function than creatinine. The aim was therefore to evaluate the prognostic value of cystatin C in this population.
Four hundred and twenty-eight patients with an ACS, admitted to our coronary care unit (CCU), were studied prospectively. Sixty-three per cent presented a non-ST-segment elevation myocardial infarction (NSTEMI) and 37% a ST-segment elevation myocardial infarction (STEMI). During their hospitalization we registered cardiovascular risk factors: we determined the presence of microalbuminuria (>3 mg/dl) in a 24-hour urine sample. We also took blood samples during the first 24 hours of their admittance to the CCU for a complete hemogram, levels of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, creatinine, creatinine clearance (Cockroft-Gault equation), glucose, HbAc1, high-sensibility C-reactive protein, Cystatin C and a follow-up of levels of Troponin, CK and CK-MB. All patients were submitted to a coronary angiography in the first 72 hours to give a clinical score to their coronary artery disease (disease of one, two or three arteries).
We determined the Cystatin C level in 59 patients (16 females and 43 males). In 36% (21 patients) we found normal levels (<0.95; 0.80 ± 0.9), called group 1. In the other group (group 2) we found higher levels of Cystatin C (>0.95; 1.63 ± 0.77). Patients in group 2 presented a higher age, a higher frequency of high blood pressure, worse Killip class score at the moment of admittance, higher inflammatory activity (leucocytosis, P = 0.001 and higher levels of C reactive protein, P = 0.005), higher grade of renal dysfunction (P = 0.001) and anaemia (P = 0.06). Patients in group 2 presented a worse intrahospital prognosis with a higher incidence of cardiac insufficiency (45% to 14%, P = 0.01), ventricular arrhythmias (29% to 5%, P = 0.05), pericardial effusion (18% to 0%, P = 0.05) and a higher mortality (21% to 5%, P = 0.08). In the multivariant analysis, Cystatin C was an independent predictor of cardiac insufficiency (OR = 4.5, 95% CI 1.1–20.8, P = 0.05).
Higher levels of Cystatin C (>0.95) in patients with an ACS indicate a worse intrahospital prognosis and also a higher inflammatory activity and renal dysfunction.