A Randomized Trial of Carvedilol in Chronic Chagas Cardiomyopathy

Study Overview
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Brief Summary
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Chronic Chagas cardiomyopathy causes substantial morbidity and mortality in Latin America. Whether RAS inhibitors and beta-blockers are safe and beneficial has been challenged because of the lack of formal trials. Hence, the objective of this study was to determine the safety and efficacy of renin-angiotensin system (RAS) inhibitors and beta-blockers in chronic Chagas cardiomyopathy. This way, the investigators conducted a double-blind, placebo-controlled, and randomized trial in 42 patients with Trypanosoma cruzi infection and cardiomyopathy. All patients received enalapril (up-titrated to 20 mg BID) and spironolactone (25 mg QD). Subsequently, the patients were randomly assigned to receive placebo (n = 20) or carvedilol up-titrated to 25 mg BID (n = 19). The primary end points were change in left ventricular ejection fraction (LVEF) after RAS inhibition and that after the addition of carvedilol. The secondary end points were changes in other echocardiographic parameters, Framingham score, quality of life (36-item Short-Form Health Survey), New York Heart Association class, radiographic indices, brain natriuretic peptide levels, and chemokines as well as safety end points.

Detailed Description
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Chronic Chagas cardiomyopathy (CCC) is an important cause of heart failure (HF) and sudden death in Latin America.1 According to recent estimates, 13 million people worldwide are infected with Trypanosoma cruzi, of whom 3.0 to 3.3 million are symptomatic.2 The incidence rate is 200000 cases per year. Among those infected, 30% have clinical features of CCC and 15% ultimately develop overt left ventricular (LV) insufficiency-the main prognostic determinant of the disease. In Chagas cardiomyopathy, the hemodynamic and neurohormonal responses do not differ from those in other cardiomyopathies. This common pathophysiology suggests that treatments shown to be effective by classic HF trials should be beneficial in CCC. However, CCC has several specific characteristics, such as early cardiac denervation, frequent ventricular arrhythmias, and several forms as well as grades of conduction disturbances, including sinus bradycardia, complete atrioventricular block, and right bundle-branch block. Morphologically, hypertrophy, dilatation, and severe fibrosis are prominent. In 20% to 40% of cases, an apical ventricular aneurysm is present.1 These peculiarities in combination lead to a high incidence of sudden death (60% of all deaths), cardiac insufficiency, and ventricular remodeling. The responses of patients to the usual drugs prescribed in HF could be different, and this perception has led to the suboptimal dosing or lack of initiation of medical treatments that are of proven efficacy in patients with other etiologies of HF. The underlying problem is that therapies that are effective in patients with HF caused by non-chagasic cardiomyopathies, such as those with renin-angiotensin system inhibitors (RASis) and h-blockers, have yet to be formally tested in CCC. There are few clinical trials and no randomized study on this subject. Consequently, the investigators evaluated the effects of optimizing treatment with enalapril and spironolactone and then undertook a randomized trial of adding a h-blocker in the treatment of patients with CCC.

Official Title
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A Randomized Trial of Carvedilol After Renin-angiotensin System Inhibition in Chronic Chagas Cardiomyopathy

Conditions
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Chagas Cardiomyopathy, Heart Failure, Dilated Cardiomyopathy

Intervention / Treatment
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* Drug: RASi plus carvedilol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Criteria for inclusion were positivity for T cruzi as confirmed by 2 or more serological tests (indirect immunofluorescence, ELISA, and/or indirect hemagglutination) and having cardiomyopathy. Cardiomyopathy was present when at least 3 of the following criteria were fulfilled: LV enddiastolic diameter (LVDD) N55 mm LVDD/body surface area > 2.7cm/m2 LV ejection fraction (LVEF) < 55% QRS interval > 120 ms echocardiographic evidence of diffuse or segmental systolic wall motion abnormalities. Exclusion Criteria: Exclusion criteria were being pregnant Using any h-blocker Having additional comorbidities (eg, hypertension, diabetes mellitus, thyroid dysfunction, chronic obstructive pulmonary disease, asthma, and renal or hepatic failure).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: RASi plus placebo<br>RAS inhibition was optimized and after patients were randomly assigned to receive placebo | |
| Experimental: RASi plus carvedilol<br>RAS inhibition was optimized and after patients were randomly assigned to receive carvedilol | Drug: RASi plus carvedilol<br>* Patients were randomly assigned to 2 groups, with 1 group receiving renin-angiotensin system inhibitors (enalapril) plus carvedilol and the other receiving renin-angiotensin system inhibitors (enalapril) plus placebo<br>* Other names: Trial;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in left ventricular ejection fraction |  | Baseline, 4 months and 8 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Framingham score |  | Baseline, 4 months and 8 months | 
| Changes in quality of life (36-item Short-Form Health Survey) |  | Baseline, 4 months and 8 months | 
| Changes in New York Heart Association functional class |  | Baseline, 4 months and 8 months | 
| Changes in cardiothoracic ratio |  | Baseline, 4 months and 8 months | 
| Changes in echocardiographic diastolic function indices |  | Baseline, 4 months and 8 months | 
| Changes in brain natriuretic peptide levels |  | Baseline, 4 months and 8 months | 
| Changes in chemokines |  | Baseline, 4 months and 8 months | 
| Changes in autoantibodies levels |  | Baseline, 4 months and 8 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Brain natriuretic peptide level,, Left ventricular ejection fraction,, Chagas cardiomyopathy,, Renin-angiotensin system,, Beta-blockers,, Enalapril,, Carvedilol,, Renin-angiotensin system inhibitors,, Chemokines