0568: The role of brain natriuretic peptide and cystatin C in the evaluation of left ventricular diastolic dysfunction: correlation with echocardio-graphic indexes after myocardial infarction in patients without systolic dysfunction

Abstract

The utility of Brain Natriuretic Peptide (BNP) and cystatin C for detecting left ventricular (LV) diastolic dysfunction after myocardial infarction (MI) in patients without heart failure symptoms still unclear. In this study, we investigated the relation between BNP, serum cystatin C levels and LV diastolic dysfunction after MI in patients without systolic dysfunction. We studied 127 patients without renal dysfunctionafter first acute coronary syndrome (ACS). LV diastolic function was assessed with conventional Doppler, by means of mitral inflow and with tissue Doppler echocardiography by means of mitral annulus. The ratio of early diastolic transmitral E wave velocities to tissue Doppler mitral annulus early diastolic E’ wave velocities (E/E’), was used to detect LV filling pressures. Patients were divided in three groups according to E/E’ ratios <10 (group I), E/E’ ratios “between” 10 and 15 (group II) and E/E’ ratios >15 (group III). Plasma concentrations of BNP and serum cystatin C were measured at admission. The BNP and serum cystatin C levels were positively correlated significantly with E/E’ ratio (r=0.786, p<0.001 and r=0.458, p=0.02). Patients with elevated LV end diastolic pressure (LVEDP), defined as E/E’ >15 had highest BNP (321±75pg/mL) and cystatin C (1.1±0.2mg/L) levels. E/E’ 10 to 15 group had a mean BNP level of 151±28pg/mL and a mean cystatin C value of 0.78±0.1mg/L, and those with E/E’ <10 had a mean BNP value of 69±20pg/mL. A BNP value of 89pg/ml had a sensitivity of 84% and a specificity of 69% for predicting E/E’ >15. The assessment of the blood concentration of BNP and cystatin C is of potential value for identification of those patients after myocardial infarction to detect early cardiovascular changes, especially LV diastolic dysfunction.