Brain natriuretic peptide predicts survival in Chagas’ disease more effectively than atrial natriuretic peptide

Chagas’ disease, caused by the protozoan Trypanosoma cruzi, remains a leading cause of heart disease in Latin America. It is believed that approximately 20 million people are infected with this parasite. An acute phase follows the parasite infection and is characterised by an active infection, inflammation, and myocardial damage.1 Symptoms of chronic cardiomyopathy develop in 20–30% of previously asymptomatic individuals decades after initial infection. Severe congestive heart failure (CHF) is a common finding, and necropsies show notable dilation of all four cardiac chambers. Areas of extensive myocardial fibrosis and left ventricular apical aneurysms are common findings. Although atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are predictive of left ventricular hypertrophy and dysfunction, they respond differently, for example, to cardiac volume load in fetal circulation or diabetic cardiomyopathy. BNP has recently gained increased importance in the clinical diagnosis of cardiovascular diseases, and BNP guided treatment of CHF was found to reduce cardiovascular morbidity. The major studies and clinical trials on CHF have excluded Chagas patients. Thus the aim of our study was: firstly, to describe plasma ANP and BNP concentrations in Chagas patients compared to controls as a screening test for ventricular dysfunction; secondly, to investigate a possible correlation with the functional New York Heart Association (NYHA) class and left ventricular ejection fraction (LVEF) and the prognostic potency in Chagas’ disease; and thirdly, to compare peptide concentrations with those in patients with other dilated cardiomyopathies (DCM) in order to investigate this tool as a diagnostic marker for discriminating between the two types of heart failure.