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

Abstract

BackgroundPrevious 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.ObjectivesTo 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.MethodsPatients were admitted one after another. Their clinical history was collected and they were submitted to laboratory exams and an MRI.ResultsSixty-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).ConclusionThe 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.

Cardiovascular Magnetic Resonance Imaging Evidence of Edema in Chronic Chagasic Cardiomyopathy

“…Our confirmation of myocardial fibrosis in Chagas-seropositive patients, in different stages of disease severity, coincides with previous studies that reported myocardial fibrosis in patients within the indeterminate form [22]. Previous studies have quantified myocardial fibrosis by CMR in Chagas disease patients [16, 26, 27]. Rochitte et al evaluated CMR with the use of LGE and reported fibrosis in 68.6% of all individuals evaluated and 100% in those with ventricular tachycardia [15].…”

“…In Figure 3, it is possible to visualize a structural organization for the variables and categories in a dimensional space, which allows the identification of patterns in the data and associations between the investigated parameters. Although we observed a heterogeneous LGE pattern, as previously reported [26, 27], an association between belonging to G3 and the presence of LGE in the subendocardial segment in apical and mesial locations were found in the MCA analysis, whose first two dimensions accounted for almost 60% of the variability between groups. An association between belonging to G3 and the presence of LGE in the subendocardial segment in apical and mesial locations is easy to perceive in Figure 3.…”

“…Rochitte et al evaluated CMR with the use of LGE and reported fibrosis in 68.6% of all individuals evaluated and 100% in those with ventricular tachycardia [15]. Noya-Rabelo et al detected LGE in 64% of patients with Chagas disease [27]. In addition, Regueiro et al reported fibrosis in 7.4% of patients in the indeterminate form, 15.8% in the cardiac stage without ventricular dysfunction, and 52.4% in those with ventricular dysfunction.…”

Early impairment of myocardial deformation assessed by regional speckle-tracking echocardiography in the indeterminate form of Chagas disease without fibrosis detected by cardiac magnetic resonance

“…Several reasons may be responsible for these discrepancies. Different from other reported series, in which patients were enrolled from cardiologic clinics or specialized tertiary centers [ 24 , 44 ], in our study subjects were selected from a broad population (n = 325) of serologically positive but asymptomatic subjects, which were not patients of any cardiologic clinic. Moreover, they were subjects tested serologically for CD because of less ominous conditions, such as a pre-operatory evaluation, blood donation, or other non-cardiologic situation.…”

Menor Prevalência e Extensão da Aterosclerose Coronária na Doença de Chagas Crônica por Angiotomografia Coronária

“…16 Foi demonstrado que uma perfusão miocárdica anormal e mesmo cicatriz miocárdica extensa podem ocorrer em pacientes chagásicos na ausência de estenose coronária epicárdica. 17,18 A fibrose miocárdica em pacientes com doença de Chagas pode ser detectada em fases iniciais da doença e precisamente quantificada por ressonância magnética cardíaca, 19,20 e sua magnitude tem significância prognóstica comprovada. 21 Apesar da alta prevalência de fatores de risco para DAC, incluindo tabagismo, estudos iniciais que indicavam uma baixa prevalência de DAC significativa por angiografia coronária invasiva em pacientes com cardiomiopatia chagásica grave sugeriram uma prevalência distinta de DAC em pacientes com doença de Chagas.…”