Microvascular Endothelial Function in a Cohort of Patients With the Cardiac Form of Chronic Chagas Disease.

Chagas disease is an endemic anthropozoonosis in South America, caused by the protozoaTrypamosoma cruzi. Between 15 and 17 million people are estimated to be infected by the parasite in South America. During the chronic phase, 30 to 40% of patients develop the cardiac or intestinal forms of the disease. The myocardial involvement is divided in two subtypes, according to the presence or absence of systolic ventricular dysfunction. The first type is characterized by heart failure symptoms. The second is acknowledged by the development of various degrees of atrioventricular blockade and by tachyarrhythmias. Microcirculation function is recognized as a fundamental aspect in the pathophysiology of cardiovascular diseases. The identification of endothelial dysfunction by techniques that assess the microvasculature is considered as both a progression and prognostic marker in various conditions, including hypertension, coronary heart disease, and heart failure. The effects of T. cruzi infection in vascular function were evaluated in previous studies, performed in animals with acute infection. Previous studies in humans observed medium size vessels (brachial artery), in small groups of patients, most without cardiac dysfunction. There are no studies evaluating the microcirculation of patients with the cardiac form of Chagas disease.