Myocardial Delayed Enhancement by Magnetic Resonance Imaging in Patients With Chagas’ Disease
Key result
MRI delayed enhancement detects myocardial fibrosis in ~69% of Chagas patients, increasing with disease severity.
- P<0.001
- n=51
Why the study?
Does myocardial delayed enhancement by MRI quantify myocardial fibrosis and correlate with disease severity in patients with Chagas' heart disease?
Key Points
- To evaluate whether myocardial delayed enhancement by magnetic resonance imaging can detect and quantify myocardial fibrosis to define disease severity in patients with Chagas heart disease.
- Enrolled 51 patients categorized into an indeterminate asymptomatic phase (n=15), known clinical Chagas heart disease (n=26), and Chagas heart disease with ventricular tachycardia (n=10).
- Acquired left ventricular short-axis slices on a 1.5-T MRI system using cine-MRI to measure ventricular function and inversion-recovery gradient-echo sequences to detect myocardial delayed enhancement.
- Myocardial fibrosis was present in 68.6% of all patients, occurring in 20% of indeterminate phase, 84.6% of clinical Chagas heart disease, and 100% of ventricular tachycardia patients (p < 0.001).
- Quantified fibrosis increased across clinical subgroups (0.9 ± 2.3% in indeterminate, 16.0 ± 12.3% in clinical disease, 25.4 ± 9.8% in ventricular tachycardia; p < 0.001) and NYHA classes (I: 7.5 ± 9.5%, II: 21.9 ± 13.8%, III: 25.3 ± 9.9%; p < 0.001).
- Fibrosis correlated inversely with left ventricular ejection fraction (r = -0.78, p < 0.001) and increased progressively from normal wall segments (4.9 ± 15.1%) to akinetic and dyskinetic segments (72.3 ± 36.2%, p < 0.001).
Study Design
Type
Observational (n=51)
Structured PICO
Does myocardial delayed enhancement by MRI quantify myocardial fibrosis and correlate with disease severity in patients with Chagas' heart disease?
P
Population
51 patients with Chagas' heart disease, including 15 asymptomatic, 26 with clinical disease, and 10 with ventricular tachycardia, evaluated for myocardial fibrosis.
E
Exposure
1.5-T MRI system using cine-MRI (LV function) and inversion-recovery gradient-echo (myocardial delayed enhancement) to quantify myocardial fibrosis.
O
Outcome
Quantification of myocardial fibrosis (MF) and its correlation with disease severity subgroups, NYHA functional classes, and left ventricular ejection fraction.surrogate
Main Result
p-value: p=<0.001
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Myocardial fibrosis is one of the most important biological markers of Chagas' cardiomyopathy and is directly related to the severity of the cardiomyopathy and the stage of the disease. In addition, myocardial fibrosis has prognostic value for major cardiovascular events, with a strong and close relationship with arrhythmic events in these patients.”
“A study of 51 patients with Chagas disease using late enhancement technique has identified images compatible with myocardial fibrosis in 20% of the 15 patients with the indeterminate form.”
Implication
Myocardial delayed enhancement by MRI can quantify myocardial fibrosis in Chagas' heart disease, detecting it in early asymptomatic stages and correlating strongly with disease severity and left ventricular dysfunction.
Abstract
OBJECTIVES: We sought to investigate whether myocardial delayed enhancement (MDE) by magnetic resonance imaging (MRI) could quantify myocardial fibrosis (MF) in patients with Chagas' heart disease (CHD), thus defining the severity of the disease. BACKGROUND: Myocardial fibrosis secondary to ischemic disease can be imaged using MDE. Advanced CHD is characterized by progressive MF. METHODS: Fifty-one patients with CHD were enrolled: 15 seropositive asymptomatic participants in the indeterminate phase (IND); 26 patients with known clinical CHD; and 10 patients with known CHD and ventricular tachycardia (VT). Using a 1.5-T MRI system, we acquired left ventricular (LV) short-axis slices using cine-MRI (LV function) and inversion-recovery gradient-echo (MDE). RESULTS: Myocardial fibrosis by MRI was present in 68.6% of all patients, in 20% of IND, 84.6% of CHD, and 100% of VT (p < 0.001). Quantified MF increased progressively across disease severity subgroups (0.9 +/- 2.3% in IND; 16.0 +/- 12.3% in CHD; and 25.4 +/- 9.8% in VT, p < 0.001) and New York Heart Association functional classes (I: 7.5 +/- 9.5%; II: 21.9 +/- 13.8%; and III: 25.3 +/- 9.9% of LV mass, p < 0.001). Left ventricular ejection fraction and MF had significant negative correlation (r = -0.78, p < 0.001), similar to the segmental MF and function: 4.9 +/- 15.1% of MF in normal function, 32.5 +/- 32.5% in mildly hypokinetic, 57.8 +/- 31.4% in severely hypokinetic, and 72.3 +/- 36.2% in akinetic and dyskinetic segments, respectively (p < 0.001). CONCLUSIONS: In CHD, MDE by MRI quantifies MF that not only can be detected in the early asymptomatic stages but parallels well-established prognostic factors and provides unique information for clinical disease staging.
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Cite This Study
Rochitte et al. (2005) conducted an observational in Chagas' heart disease (n=51). Myocardial delayed enhancement by MRI was evaluated on Presence and quantification of myocardial fibrosis (p=<0.001). Myocardial delayed enhancement by MRI detected myocardial fibrosis in 68.6% of Chagas' disease patients, with quantified fibrosis increasing progressively across disease severity subgroups (p<0.001).