The Presence and Extension of Myocardial Fibrosis in the Undetermined Form of Chagas’ Disease: A Study Using Magnetic Resonance

<div><p>Abstract Background: Previous data has shown that patients in the indeterminate form of Chagas disease may present myocardial fibrosis as shown on through magnetic resonance imaging (MRI). However, there is little information available regarding the degree of severity of myocardial fibrosis in these individuals. This variable has the potential to predict the evolution of Chagas’ disease into its cardiac form. Objectives: To describe the frequency and extent of myocardial fibrosis evaluated using an MRI in patients in the indeterminate form, and to compare it with other forms of the disease. Methods: Patients were admitted one after another. Their clinical history was collected and they were submitted to laboratory exams and an MRI. Results: Sixty-one patients with Chagas’ disease, with an average age of 58 ± 9 years old, 17 patients in the indeterminate form, 16 in the cardiac form without left ventricular (LV) dysfunction and 28 in the cardiac form with LV dysfunction were studied. P <0.05 was considered to be statistically significant. Late enhancement was detected in 37 patients (64%). Myocardial fibrosis was identified in 6 individuals in indeterminate form (41%; 95% CI 23-66) in a proportion similar to that observed in cardiac form without LV dysfunction (44%); p = 1.0. Among the individuals with fibrosis, the total area of the affected myocardium was 4.1% (IIQ: 2.1 - 10.7) in the indeterminate form versus 2.3% (IIQ: 1-5) in the cardiac form without LV (p = 0.18). The left ventricular fraction ejection in subjects in the indeterminate form was similar to that of the individuals in the cardiac form without ventricular dysfunction (p = 0.09). Conclusion: The presence of fibrosis in the indeterminate form of Chagas’ disease has a frequency and extension similar to that of in the cardiac form without dysfunction, suggesting that the former is part of a subclinical disease spectrum, rather than lacking cardiac involvement.</p></div

Lack of association between serum syndecan-4, myocardial fibrosis and ventricular dysfunction in subjects with chronic Chagas disease

<div><p>Background</p><p>Syndecan-4 is a transmembrane glycoprotein associated with inflammation and fibrosis. Increased syndecan-4 levels were previously detected after acute myocardial infarction and in subjects with heart failure. However, the levels of syndecan-4 in subjects with Chagas disease have not so far been investigated. The aim of this study was to investigate the potential role of serum sydencan-4 as a novel biomarker for myocardial fibrosis and cardiac dysfunction in subjects with Chagas disease.</p><p>Methods</p><p>This study comprised subjects with Chagas disease (n = 56), being 14 (25%) with the indeterminate form, 16 (29%) with the cardiac form without ventricular dysfunction, and 26 (46%) with the cardiac form with ventricular dysfunction.</p><p>Results</p><p>Syndecan-4 serum concentrations did not correlate with presence or absence of myocardial fibrosis (P = 0.386) nor disease severity in subjects with Chagas disease (P = 0.918). Additionally, no correlation was found either between the degree of myocardial fibrosis and serum syndecan-4 [r = 0.08; P = 0.567] or between left ventricular ejection fraction and syndecan-4 [r = 0.02; P = 0.864]. In contrast, NT-proBNP levels correlated with ejection fraction and myocardial fibrosis.</p><p>Conclusions</p><p>Our results demonstrate the lack of correlations between serum syndecan-4, myocardial fibrosis and cardiac dysfunction in subjects with Chagas disease. Further studies are required to show if syndecan-4 concentrations can be marker for prognosis assessment or disease progression.</p></div

Correlation between percentage of myocardial fibrosis assessed by cardiovascular MRI and concentration of syndecan-4 and NT-ProBNP.

<p>A: Pearson’s correlation, r = 0.08, P = 0.567. B: Pearson’s correlation, r = 0.469, P<0.001.</p

Clinical and demographic characteristics of subjects with Chagas disease.

<p>Clinical and demographic characteristics of subjects with Chagas disease.</p

Correlation between LVEF and serum concentration of syndecan-4 and NT-ProBNP.

<p>A: Pearson’s correlation, LVEF assessed by Simpson’s method, r = 0.02, P = 0.864. B = Pearson’s correlation, LVEF assessed by Simpson’s method, r = 0.687, P<0.001.</p

Echocardiographic and CMR findings in subjects with Chagas disease.

<p>Echocardiographic and CMR findings in subjects with Chagas disease.</p

Serum concentration of syndecan-4 assessed by ELISA in subjects with different forms of Chagas disease.

<p>ANOVA, P = 0.918. Circle = outlier, * = extreme outlier, P = 0.395.</p

Serum concentration of syndecan-4 assessed by ELISA in subjects with and without delayed enhancement detected by magnetic resonance imaging.

<p>Circle = outlier, * = extreme outlier, <i>t</i> test, P = 0.386.</p

Echocardiographic data in subjects with heart failure.

<p>Echocardiographic data in subjects with heart failure.</p