Related Experiment Videos
Studies of the coronary circulation in Chagas' heart disease
J A Marin-Neto1, M V Simões, E M Ayres-Neto
1Department of Internal Medicine, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
Insights
Chronic Chagas' heart disease may stem from coronary circulation issues, not just blockages. Microvascular problems likely precede and cause myocardial damage in Chagas patients.
Area of Science:
- Cardiovascular Medicine
- Infectious Diseases
- Pathogenesis
Background:
- Chagas' heart disease involves myocardial lesions potentially linked to coronary circulation disturbances.
- The vascular pathogenetic theory suggests circulatory abnormalities contribute to chronic Chagas' disease.
- Epicardial coronary arteries in Chagas patients typically show no significant obstructive disease.
Purpose of the Study:
- To critically review anatomical and functional abnormalities in chronic Chagas' heart disease related to the vascular pathogenetic theory.
- To investigate the role of microcirculatory derangements in the pathogenesis of Chagas' heart disease.
- To explore the potential for hibernating ventricular areas in Chagas patients.
Main Methods:
- Review of anatomical and functional abnormalities in chronic chagasic patients.
- Analysis of autopsy and coronary angiography data.
- Scintigraphy methods to assess myocardial perfusion in patients with normal coronary arteries.
- Investigation of vasomotor responses in epicardial coronary arteries.
Main Results:
- Epicardial coronary arteries are generally free of obstructive disease in Chagas patients.
- Myocardial perfusion abnormalities are detected in Chagas patients with normal coronary arteries.
- Microvascular disturbances are implicated as a causative mechanism for myocardial damage.
- Attenuated vasomotor responses observed in epicardial coronary arteries of chronic Chagas patients.
Conclusions:
- Microvascular disturbances, rather than obstructive epicardial disease, are likely key in Chagas' heart disease pathogenesis.
- Hypoperfusion in normally or mildly impaired wall motion regions suggests microvascular dysfunction precedes myocardial damage.
- Hibernating ventricular areas may develop in Chagas patients due to these vascular abnormalities.
Abstract:
Pathogenesis of chronic Chagas' heart disease may include various disturbances in the coronary circulation, that could be responsible for the myocardial lesions seen in human hearts and in experimental models of the disease. In this paper we critically reviewed the anatomical and functional abnormalities described in chronic chagasic patients, pertaining to the so-called vascular pathogenetic theory of Chagas' disease. The epicardial coronary arteries are usually free of significant obstructive disease in nonselected groups of chagasic patients examined at autopsy or by coronary angiography. However, chagasic patients who were studied after an episode of acute myocardial infarction, show the same patterns of atherosclerotic coronary artery disease seen in the general nonchagasic population. Studies of chagasic patients with angiographically normal coronary arteries, by several scintigraphy methods, revealed myocardial perfusion abnormalities which may be caused by the microcirculatory derangements described in animals experimentally infected with the T. cruzi. Since hypoperfusion has been detected in regions with normal or mildly impaired wall motion, it is likely that the microvascular disturbances precede and may be causative mechanism for the subsequent myocardial damage. We speculate that hibernating ventricular areas may occur in chagasic patients, on the basis of the evidence gathered from these studies. Recent investigations of chronic patients with Chagas' disease and chest pain showed attenuation of the vasomotor responses to physiological and pharmacological stimuli, in the epicardial coronary arteries.