[Natriuretic peptide in patients with Chagas disease: diagnostic utility in heart failure]

The assessment of the type-B natriuretic peptide (BNP) has shown utility as a diagnostic and prognostic tool of heart failure. The aim of this study was to evaluate the BNP levels and to know its association within the systolic dysfunction level on Chagas disease. During the period 2010-2011, 64 patients were evaluated in the Chagas clinic of the Cardiopulmonary Unit of the University Hospital Dr. Luis Razetti, Barcelona-Anzoátegui state, Venezuela. After confirming the seropositive state to antibodies anti-T. cruzi with three inmunoserological tests (ELISA, indirect inmunofluorescence and indirect hemaglutination), patients were classified into Groups I, II and III of cardiac disease, by the evaluation with electrocardiogram, echocardiogram and thorax radiography. Thirty three seronegative cardiological patients and eight healthy volunteers were included in the study as controls. BNP groups levels were as follow: Chagas I = 18.87 +/- 18.00 pg/mL (n=20), Chagas II = 99.88 +/- 171.52 pg/mL (n=24) y Chagas III = 365.80 +/- 280.54 pg/mL (n=20). The sensitivity and specificity of BNP were 85.0% and 93.2%, respectively, (p<0.0001; IC 95%), employing as parameter of reference the left ventricle fraction ejection (LVFE <40%), with a prognostic value of 89.0% (p=0.006). These results place the BNP in an equivalent position with the echocardiogram for the evaluation of cardiological patients, with the benefits of rapidity and simplicity, which makes the determination of this biochemical parameter a useful tool to perform field studies in endemic zones with limited access to the echocardiographic test.