Brain natriuretic peptide and left ventricular dysfunction in chagasic cardiomyopathy

Biomakers in Chronic Chagas Cardiomyopathy

The primary objective was to observe the relationship between serum levels of BNP, Ca-125, C-reactive protein and uric acid as prognostic and functional markers in patients with chronic Chagas cardiomyopathy (CCC). Circulating levels of cytokines: IL-1β, TNFα, IL-10, IL6, IL-8 and IL-12 were determined and investigated regarding their association with hemodynamic parameters, clinical signs of heart failure and outcome. Chagas is still a neglected disease that affects numerous individuals, many of them in their most productive years. CCC with left ventricular dysfunction is the most severe presentation of Chagas Disease. BNP is a well-recognized prognostic and clinical biomarker, not only in chronic heart failure patients but also in patients with CCC. Previous studies have shown Ca-125, C-reactive protein, and uric acid to be potentially good prognostic markers in heart failure (HF). Fifty patients with left ventricular fraction less (LVEF) than 55% were selected and followed for a mean period of 18 ± 8.3 months. Patient’s mean age was 43.42 ± 10.3 years (32 male), their BNP was 293 (160–530) pg/mL, Ca-125 8.5 (5.5–16.75) U/mL, uric acid 6.2 ± 2 mg/dL, and C- reactive protein 4.5 (4.5–7.3) mg/L. Patients who had LVEF less than 35% had higher BNP (p = 0.0023), Ca-125 (p = 0.027) and uric acid (p = 0.01) serum levels. Patients who died also showed higher BNP (p = 0.01), uric acid (p = 0.05) and a trend towards higher Ca-125 serum levels (p = 0.056). All markers: BNP, Ca-125, uric acid and C-reactive had good predictability of death in Cox-regression univariate analysis, however, not on the final multivariate model. Of the inflammatory cytokines, IL-8 and IL-12 showed a relation to LVEF of less than 35%. IL-12 was related to adverse cardiovascular events and non-survival. IL-1β was a good predictor of mortality in the final Cox regression model. Determination of Ca-125, uric acid levels and C-reactive protein may add useful clinical and prognostic information and may help clinical decision making for patients with CCC.

Prognosis of chronic Chagas heart disease and other pending clinical challenges

In this chapter, the main prognostic markers of Chagas heart disease are addressed, with an emphasis on the most recent findings and questions, establishing the basis for a broad discussion of recommendations and new approaches to managing Chagas cardiopathy. The main biological and genetic markers and the contribution of the electrocardiogram, echocardiogram and cardiac magnetic resonance are presented. We also discuss the most recent therapeutic proposals for heart failure, thromboembolism and arrhythmias, as well as current experience in heart transplantation in patients suffering from severe Chagas cardiomyopathy. The clinical and epidemiological challenges introduced by acute Chagas disease due to oral contamination are discussed. In addition, we highlight the importance of ageing and comorbidities in influencing the outcome of chronic Chagas heart disease. Finally, we discuss the importance of public policies, the vital role of funding agencies, universities, the scientific community and health professionals, and the application of new technologies in finding solutions for better management of Chagas heart disease.

Risk Score for Predicting 2-Year Mortality in Patients With Chagas Cardiomyopathy From Endemic Areas: SaMi-Trop Cohort Study

Background

Risk stratification of Chagas disease patients in the limited‐resource setting would be helpful in crafting management strategies. We developed a score to predict 2‐year mortality in patients with Chagas cardiomyopathy from remote endemic areas.

Methods and Results

This study enrolled 1551 patients with Chagas cardiomyopathy from Minas Gerais State, Brazil, from the SaMi‐Trop cohort (The São Paulo‐Minas Gerais Tropical Medicine Research Center). Clinical evaluation, ECG, and NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) were performed. A Cox proportional hazards model was used to develop a prediction model based on the key predictors. The end point was all‐cause mortality. The patients were classified into 3 risk categories at baseline (low, <2%; intermediate, ≥2% to 10%; high, ≥10%). External validation was performed by applying the score to an independent population with Chagas disease. After 2 years of follow‐up, 110 patients died, with an overall mortality rate of 3.505 deaths per 100 person‐years. Based on the nomogram, the independent predictors of mortality were assigned points: age (10 points per decade), New York Heart Association functional class higher than I (15 points), heart rate ≥80 beats/min (20 points), QRS duration ≥150 ms (15 points), and abnormal NT‐proBNP adjusted by age (55 points). The observed mortality rates in the low‐, intermediate‐, and high‐risk groups were 0%, 3.6%, and 32.7%, respectively, in the derivation cohort and 3.2%, 8.7%, and 19.1%, respectively, in the validation cohort. The discrimination of the score was good in the development cohort (C statistic: 0.82), and validation cohort (C statistic: 0.71).

Conclusions

In a large population of patients with Chagas cardiomyopathy, a combination of risk factors accurately predicted early mortality. This helpful simple score could be used in remote areas with limited technological resources.

Blood Gene Signatures of Chagas Cardiomyopathy With or Without Ventricular Dysfunction

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects 7 million people in Latin American areas of endemicity. About 30% of infected patients will develop chronic Chagas cardiomyopathy (CCC), an inflammatory cardiomyopathy characterized by hypertrophy, fibrosis, and myocarditis. Further studies are necessary to understand the molecular mechanisms of disease progression. Transcriptome analysis has been increasingly used to identify molecular changes associated with disease outcomes. We thus assessed the whole-blood transcriptome of patients with Chagas disease. Microarray analysis was performed on blood samples from 150 subjects, of whom 30 were uninfected control patients and 120 had Chagas disease (1 group had asymptomatic disease, and 2 groups had CCC with either a preserved or reduced left ventricular ejection fraction [LVEF]). Each Chagas disease group displayed distinct gene expression and functional pathway profiles. The most different expression patterns were between CCC groups with a preserved or reduced LVEF. A more stringent analysis indicated that 27 differentially expressed genes, particularly those related to natural killer (NK)/CD8+ T-cell cytotoxicity, separated the 2 groups. NK/CD8+ T-cell cytotoxicity could play a role in determining Chagas disease progression. Understanding genes associated with disease may lead to improved insight into CCC pathogenesis and the identification of prognostic factors for CCC progression.

Chagas Disease Diagnostic Applications: Present Knowledge and Future Steps

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a lifelong and debilitating illness of major significance throughout Latin America and an emergent threat to global public health. Being a neglected disease, the vast majority of Chagasic patients have limited access to proper diagnosis and treatment, and there is only a marginal investment into R&D for drug and vaccine development. In this context, identification of novel biomarkers able to transcend the current limits of diagnostic methods surfaces as a main priority in Chagas disease applied research. The expectation is that these novel biomarkers will provide reliable, reproducible and accurate results irrespective of the genetic background, infecting parasite strain, stage of disease, and clinical-associated features of Chagasic populations. In addition, they should be able to address other still unmet diagnostic needs, including early detection of congenital T. cruzi transmission, rapid assessment of treatment efficiency or failure, indication/prediction of disease progression and direct parasite typification in clinical samples. The lack of access of poor and neglected populations to essential diagnostics also stresses the necessity of developing new methods operational in point-of-care settings. In summary, emergent diagnostic tests integrating these novel and tailored tools should provide a significant impact on the effectiveness of current intervention schemes and on the clinical management of Chagasic patients. In this chapter, we discuss the present knowledge and possible future steps in Chagas disease diagnostic applications, as well as the opportunity provided by recent advances in high-throughput methods for biomarker discovery.

Inflammatory and cardiac biomarkers are differentially expressed in clinical stages of Chagas disease

BACKGROUND

Chagas disease has a long clinically silent period following Trypanosoma cruzi infection and before development of overt clinical pathology; detectable biomarkers of infection and pathogenesis are urgently needed. We tested 22 biomarkers known to be associated with cardiomyopathy to evaluate if a biomarker signature could successfully classify T. cruzi seropositive subjects into clinical Chagas disease stage groups.

METHODS

This cross-sectional retrospective case-control study enrolled T. cruzi seropositive blood donors (BD) who were further characterized as having chronic Chagas cardiomyopathy (CC-BD) or not (nonCC-BD) and seronegative (SN) control donors; we also included clinically diagnosed Chagas cardiomyopathy patients (CC-P). All subjects underwent a health history questionnaire, medical examination, electro- and echocardiograms (ECG and Echo) and phlebotomy. Biomarkers were measured on blinded samples by luminex bead array and Ortho VITROS.

RESULTS

A clear biomarker pattern was observed only in more severe cardiac disease; this pattern included significantly elevated levels of inflammatory cytokines IFN-γ, IL-6, IL-10 and TNF-α and soluble cardiovascular disease biomarkers CK-MB, troponin, myoglobin, VCAM and NTproBNP while there were lower levels of MPO, PAI-1, and MCP-1. The markers determined to be the most predictive of disease by ROC curve analysis were NTproBNP and T. cruzi PCR status.

CONCLUSIONS

Although many biomarkers demonstrated increased or decreased concentrations among the clinical forms of Chagas disease, NTproBNP and T. cruzi PCR were the only tests that would independently be of clinical value for disease staging, in concert with ECG, Echo and clinical assessments.

Biological markers for evaluating therapeutic efficacy in Chagas disease, a systematic review

The most neglected aspects of Chagas disease (CD) have been patient care and treatment. Despite recent progress in the development of potentially improved drugs, there is no consensus among different research groups on the lack of therapeutic response markers to evaluate efficacy of newly proposed drugs early after treatment. A systematic review of current evidence regarding molecules which are potential biomarkers for therapeutic response has been conducted using quality assessment and target responses as primary criteria. The review provides a panorama of the cumulative evidence and specific needs for development of a battery of complementary biomarkers which together fulfill ideal or acceptable criteria to evaluate early responses to treatment for chronic CD. There are several marker candidates which together may fulfill acceptable criteria to indicate the efficacy of a trypanocidal treatment. Data from ongoing studies are considered essential to improve assessment of existing markers and to identify those for early follow-up of treated patients.

Clinical and echocardiographic predictors of mortality in chagasic cardiomyopathy--systematic review

Diagnosis, prognosis and evaluation of death risk in Chagas cardiomyopathy still constitute a challenge due to the diversity of manifestations, which determine the importance of using echocardiography, tissue Doppler and biomarkers. To evaluate, within a systematic review, clinical and echocardiographic profiles of patients with chronic chagasic cardiomyopathy, which may be related to worse prognosis and major mortality risk. To perform the systematic review, we used Medline (via PubMed), LILACS and SciELO databases to identify 82 articles published from 1991 to 2012, with the following descriptors: echocardiography, mortality and Chagas disease. We selected 31 original articles, involving diagnostic and prognostic methods. The importance of Chagas disease has increased due to its emergence in Europe and United States, but most evidence came from Brazil. Among the predictors of worse prognosis and higher mortality risk are morphological and functional alterations in the left and right ventricles, evaluated by conventional echocardiography and tissue Doppler, as well as the increase in brain natriuretic peptide and troponin I concentrations. Recently, the evaluations of dyssynchrony, dysautonomia, as well as strain, strain rate and myocardial twisting were added to the diagnostic arsenal for the early differentiation of Chagas cardiomyopathy. Developments in imaging and biochemical diagnostic procedures have enabled more detailed cardiac evaluations, which demonstrate the early involvement of both ventricles, allowing a more accurate assessment of the mortality risk in Chagas disease.

Electrocardiographic abnormalities in elderly Chagas disease patients: 10-year follow-up of the Bambui Cohort Study of Aging

Background

Electrocardiography has been considered an important tool in the management of Chagas disease (ChD) patients, although its value in elderly infected patients is unknown. This study was designed to investigate the prevalence and prognostic value of electrocardiographic abnormalities in Trypanosoma cruzi infected and noninfected older adults.

Methods and Results

We studied 1462 participants in Bambuí City, Brazil, with electrocardiogram (ECG) records classified by the Minnesota Code. Follow‐up time was 10 years; the endpoint was mortality. Adjustment for potential confounding variables included age, gender, conventional risk factors, and B‐type natriuretic peptide (BNP). The mean age was 69 years (60.9% women). The prevalence of ChD was 38.1% (n=557). ECG abnormalities were more frequent in ChD patients (87.6% versus 77.7%, P<0.001). Right bundle branch block (RBBB) with left anterior hemiblock (LAH) was strongly related to ChD (OR: 11.99 [5.60 to 25.69]). During the mean follow‐up time of 8.7 years, 556 participants died (253 with ChD), and only 89 were lost to follow‐up. ECG variables of independent prognostic value for death in ChD included absence of sinus rhythm, frequent ventricular and supraventricular premature beats, atrial fibrillation, RBBB, old and possible old myocardial infarction, and left ventricular hypertrophy. The presence of any major ECG abnormalities doubled the risk of death in ChD patients (HR: 2.18 [1.35 to 3.53]), but it also increased the risk in non‐ChD subjects (HR: 1.50 [1.07 to 2.10]); the risk of death increased with the number of major abnormalities in the same patient.

Conclusion

ECG abnormalities are more common among elderly Chagas disease patients and strongly predict adverse outcomes.

Current understanding of immunity to Trypanosoma cruzi infection and pathogenesis of Chagas disease

Chagas disease caused by Trypanosoma cruzi remains an important neglected tropical disease and a cause of significant morbidity and mortality. No longer confined to endemic areas of Latin America, it is now found in non-endemic areas due to immigration. The parasite may persist in any tissue, but in recent years, there has been increased recognition of adipose tissue both as an early target of infection and a reservoir of chronic infection. The major complications of this disease are cardiomyopathy and megasyndromes involving the gastrointestinal tract. The pathogenesis of Chagas disease is complex and multifactorial involving many interactive pathways. The significance of innate immunity, including the contributions of cytokines, chemokines, reactive oxygen species, and oxidative stress, has been emphasized. The role of the components of the eicosanoid pathway such as thromboxane A(2) and the lipoxins has been demonstrated to have profound effects as both pro- and anti-inflammatory factors. Additionally, we discuss the vasoconstrictive actions of thromboxane A(2) and endothelin-1 in Chagas disease. Human immunity to T. cruzi infection and its role in pathogen control and disease progression have not been fully investigated. However, recently, it was demonstrated that a reduction in the anti-inflammatory cytokine IL-10 was associated with clinically significant chronic chagasic cardiomyopathy.

Chronic Chagas' heart disease: a disease on its way to becoming a worldwide health problem: epidemiology, etiopathology, treatment, pathogenesis and laboratory medicine

Chagas' disease, caused by Trypanosoma cruzi infection, is ranked as the most serious parasitic disease in Latin America. Nearly 30% of infected patients develop life-threatening complications, and with a latency of 10-30 years, mostly Chagas' heart disease which is currently the major cause of morbidity and mortality in Latin America, enormously burdening economic resources and dramatically affecting patients' social and labor situations. Because of increasing migration, international tourism and parasite transfer by blood contact, intrauterine transfer and organ transplantation, Chagas' heart disease could potentially become a worldwide problem. To raise awareness of this problem, we reflect on the epidemiology and etiopathology of Chagas' disease, particularly Chagas' heart disease. To counteract Chagas' heart disease, in addition to the general interruption of the infection cycle and chemotherapeutic elimination of the infection agent, early and effective causal or symptomatic therapies would be indispensable. Prerequisites for this are improved knowledge of the pathogenesis and optimized patient management. From economic and logistics viewpoints, this last prerequisite should be performed using laboratory medicine tools. Consequently, we first summarize the mechanisms that have been suggested as driving Chagas' heart disease, mainly those associated with the presence of autoantibodies against G-protein-coupled receptors; secondly, we indicate new treatment strategies involving autoantibody apheresis and in vivo autoantibody neutralization; thirdly, we present laboratory medicine tools such as autoantibody estimation and heart marker measurement, proposed for diagnosis, risk assessment and patient guidance and lastly, we critically reflect upon the increase in inflammation and oxidative stress markers in Chagas' heart disease.

Cardiac troponin T measured with a highly sensitive assay for diagnosis and monitoring of heart injury in chronic Chagas disease

CONTEXT

Chronic Chagas disease (15 million patients; annual incidence, 40, 000 patients; annual mortality, 12 ,500 patients) is the most serious parasitic disease in Latin America. Between 10 and 30 years after infection, 30% of patients with Chagas disease develop heart injury, which is the main reason for its high mortality. Consequently, frequent cardiac diagnostics are required for patients with Chagas disease.

OBJECTIVE

To minimize time-intensive and cost-intensive diagnostics, such as electrocardiography, echocardiography, and radiologic imaging, we tested the effect of measuring serum cardiac troponin T (cTnT) with a highly sensitive assay. To indicate the pathophysiologic background for cTnT release in Chagas heart injury, inflammation markers, such as C-reactive protein and interleukin 6, were measured in parallel.

DESIGN

Serum cTnT was measured in 26 healthy subjects and in 179 patients with chronic Chagas disease who were asymptomatic (indeterminate stage, n  =  86), who were suffering from cardiomyopathy with or without megacolon (n  =  71), or who were suffering from megacolon exclusively (n  =  22).

RESULTS

Serum cTnT was significantly higher in patients with cardiomyopathy with or without megacolon than in healthy subjects, asymptomatic subjects, and patients with megacolon, and the cTnT value was correlated with the severity of the cardiomyopathy. The lower limit of detection for the highly sensitive assay (3 ng/L) was best at distinguishing patients with, and without, heart injury. C-reactive protein and interleukin 6 were found to parallel cTnT changes in both the different Chagas groups and the cardiomyopathy groups separated by disease severity.

CONCLUSIONS

Highly sensitive cTnT measurement has the potential to contribute to diagnosis and monitoring of heart injury in patients with chronic Chagas disease. The highly sensitive assay of cTnT release seems to be related to Chagas heart disease-specific inflammation.

Inflammation and Chagas disease some mechanisms and relevance

Chagas cardiomyopathy is caused by infection with flagellated protozoan Trypanosoma cruzi. In patients, there is a fine balance between control of the replication and the intensity of the inflammatory response so that the host is unable to eliminate the parasite resulting in the parasite persisting as a lifelong infection in most individuals. However, the parasite persists in such a way that it causes no or little disease. This chapter reviews our understanding of many of the mediators of inflammation and cells which are involved in the inflammatory response of mammals to T. cruzi infection. Particular emphasis is given to the role of chemokines, endothelin and lipid mediators. Understanding the full range of mediators and cells present and how they interact with each other in Chagas disease may shed light on how we modulate disease pathogenesis and define new approaches to treat or prevent the disease.

Chagas cardiomyopathy: the potential of diastolic dysfunction and brain natriuretic peptide in the early identification of cardiac damage

INTRODUCTION

Chagas disease remains a major cause of mortality in several countries of Latin America and has become a potential public health problem in non-endemic countries as a result of migration flows. Cardiac involvement represents the main cause of mortality, but its diagnosis is still based on nonspecific criteria with poor sensitivity. Early identification of patients with cardiac involvement is desirable, since early treatment may improve prognosis. This study aimed to assess the role of diastolic dysfunction, abnormal myocardial strain and elevated brain natriuretic peptide (BNP) in the early identification of cardiac involvement in Chagas disease.

METHODOLOGY/PRINCIPAL FINDINGS

Fifty-four patients divided into 3 groups--group 1 (undetermined form: positive serology without ECG or 2D-echocardiographic abnormalities; N = 32), group 2 (typical ECG abnormalities of Chagas disease but normal 2D-echocardiography; N = 14), and group 3 (regional wall motion abnormalities, left ventricular [LV] end-diastolic diameter >55 mm or LV ejection fraction <50% on echocardiography; N = 8)--and 44 control subjects were studied. Patients with significant non-cardiac diseases, other heart diseases and previous treatment with benznidazol were excluded. The median age was 37 (20-58) years; 40% were men. BNP levels, longitudinal and radial myocardial strain and LV diastolic dysfunction increased progressively from group 1 to 3 (p for trend <0.01). Abnormal BNP levels (>37 pg/ml) were noted in 0%, 13%, 29% and 63% in controls and groups 1 to 3, respectively. Half of patients in the undetermined form had impaired relaxation patterns, whereas half of patients with ECG abnormalities suggestive of Chagas cardiomyopathy had normal diastolic function. In group 1, BNP levels were statistically higher in patients with diastolic dysfunction as compared to those with normal diastolic function (27 ± 26 vs. 11 ± 8 pg/ml, p = 0.03).

CONCLUSION/SIGNIFICANCE

In conclusion, the combination of diastolic function and BNP measurement adds important information that could help to better stratify patients with Chagas disease.

Plasma B-type natriuretic peptide as a predictor of mortality in community-dwelling older adults with Chagas disease: 10-year follow-up of the Bambui Cohort Study of Aging

In this study, the authors aimed to investigate the prognostic value of brain-type natriuretic peptide (BNP) for all-cause mortality among persons with Chagas disease, a parasitic disease caused by the protozoan Trypanosoma cruzi. The authors used data on 1,398 participants (37.5% infected with T. cruzi) aged 60 years and over from the Bambuí Cohort Study of Aging in Brazil. From 1997 to 2007, 512 participants died, leading to 12,406 person-years of observation. The hazard ratio for death was 1.27 for each unit of log-transformed BNP level (95% confidence interval (CI: 1.11, 1.45) among infected persons, independent of potentially confounding factors. Infected persons with baseline BNP levels in the top quartile had a risk of death twice that of persons in the bottom quartile (hazard ratio = 2.07, 95% CI: 1.29, 3.32). The discriminatory ability of BNP in predicting mortality (C = 0.69, 95% CI: 0.66, 0.71) was similar to that of an electrocardiogram (C = 0.68, 95% CI: 0.65, 0.71), with reasonably stable risk discrimination over time. BNP is a strong predictor of mortality in older adults with Chagas disease. Although the usefulness of BNP for risk stratification in this parasitic disease remains a topic of debate, this study found that BNP-based risk discrimination is at least comparable to that of an electrocardiogram.

Chagas cardiomyopathy--where do we stand after a hundred years?

A hundred years from its description, Chagas cardiomyopathy remains a challenging disease. Although successful vector-control strategies have decreased the incidence of Chagas disease in several Latin American countries, both migration to urban areas and immigration have spread the disease worldwide; and now, blood transfusion, organ transplantation, and vertical transmission are a concern. The pathogenesis of Chagas cardiomyopathy involves complex host-parasite interactions, where low-grade but incessant systemic infection and triggered autoimmune reaction are the main mechanisms for its development, with the contribution of autonomic damage and microvascular disturbances. Chagas cardiomyopathy is the most important clinical presentation of Chagas disease and comprises a wide range of manifestations, including heart failure, arrhythmias, heart blocks, sudden death, thromboembolism, and stroke. Recently, simple clinical prognostic scores have been developed to identify high-risk patients and help with management. The treatment of Chagas cardiomyopathy focuses mostly on managing heart failure, arrhythmias, and thromboembolism. The role of specific antiparasitic therapy in the chronic form is not yet defined, and a randomized trial is now under way to address this crucial point. In this article, we review the main clinical aspects of Chagas cardiomyopathy and underscore some upcoming challenges for the appropriate control, diagnosis, and management of this complex disease.

Cardiac involvement in African and American trypanosomiasis

American trypanosomiasis (Chagas disease) and human African trypanosomiasis (HAT; sleeping sickness) are both caused by single-celled flagellates that are transmitted by arthropods. Cardiac problems are the main cause of morbidity in chronic Chagas disease, but neurological problems dominate in HAT. Physicians need to be aware of Chagas disease and HAT in patients living in or returning from endemic regions, even if they left those regions long ago. Chagas heart disease has to be taken into account in the differential diagnosis of cardiomyopathy, primarily in patients with pathological electrocardiographic (ECG) findings, such as right bundle branch block or left anterior hemiblock, with segmental wall motion abnormalities or aneurysms on echocardiography, and in young patients with stroke in the absence of arterial hypertension. In HAT patients, cardiac involvement as seen by ECG alterations, such as repolarisation changes and low voltage, is frequent. HAT cardiopathy in general is benign and does not cause relevant congestive heart failure and subsides with treatment. We review the differences between the American and African trypanosomiasis with the main focus on the heart.

Invasive and noninvasive correlations of B-type natriuretic peptide in patients with heart failure due to Chagas cardiomyopathy

Heart failure due to Chagas cardiomyopathy (HFCC) differs from failure with other etiologies because of the occurrence of intense inflammatory infiltrate and right ventricle compromise. This article investigates correlations of B-type natriuretic peptide (BNP) levels with parameters of severity in HFCC. Twenty-eight patients and 8 normal controls underwent heart catheterization and clinical and laboratory analyses. BNP levels were higher in patients with HFCC (P<.0001) and correlated with New York Heart Association (NYHA) class; right atrial pressure; wedge pressure; cardiac output; levels of serum sodium, hemoglobin, urea, and tumor necrosis factor-alpha; and ejection fraction. Interferon-gamma and transforming growth factor-beta did not correlate with BNP level. The authors conclude that BNP levels are elevated in patients experiencing HFCC, irrespective of NYHA class, and that the occurrence of HFCC correlates with severity of disease.

Treatment of chronic systolic heart failure secondary to Chagas heart disease in the current era of heart failure therapy

The treatment of chronic heart failure secondary to Chagas disease has been based on extrapolation of data achieved in the treatment of non-Chagas disease heart failure. Because beta-blockers decrease the incidence of sudden cardiac death in non-Chagas disease heart failure and sudden cardiac death occurs preferentially in patients with mild Chagas disease heart failure, beta-blockers may be administered first to class I/II patients with Chagas disease heart failure. In advanced Chagas disease heart failure, angiotensin-converting enzyme inhibitor and diuretics may be given at first to compensate for congestive symptoms. After clinical status improvement, beta-blockers should be given at targeted doses, if necessary reducing angiotensin-converting enzyme inhibitor doses. Primary and secondary prevention of sudden cardiac death may be accomplished with implantable cardioverter defibrillators because of the high recurrence of life-threatening arrhythmias despite amiodarone administration. In refractory heart failure, heart transplantation is the treatment of choice.

An update on the management of Chagas cardiomyopathy

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, infects nearly 18 million people in Latin America and mainly affects the heart, causing heart failure, arrhythmias, heart block, thromboembolism, stroke and death. In this review, the clinical diagnosis and management of Chagas cardiomyopathy are discussed. Particular emphasis is placed on the clinical staging of patients and the use of various diagnostic tests that may be useful in individualizing treatment of the two most relevant clinical syndromes, that is, heart failure and arrhythmias. The relevance of specific treatments are discussed, stressing the important role of parasite persistence in disease pathogenesis. We also discuss new therapy modalities that may have a role in the treatment of Chagas cardiomyopathy.

A randomized trial of carvedilol after renin-angiotensin system inhibition in chronic Chagas cardiomyopathy

OBJECTIVE

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.

BACKGROUND

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.

METHODS

We 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.

RESULTS

Optimization of RAS inhibition was safe, hemodynamically well tolerated, and associated with improvements in Framingham score (P = .001) and quality of life as well as reductions in the cardiothoracic index (P = .002), brain natriuretic peptide level (P = .032), and RANTES (regulated on activation, normal T expressed and secreted) level (P = .001). Left ventricular ejection fraction increased by 2.3% (P = .25); in patients with an LVEF < or = 45% at baseline, it increased by 2.8% (P = .017). Treatment with carvedilol was associated with a trend toward an increase in LVEF (absolute difference between groups, 2.3%; P = .094). The addition of carvedilol was safe, hemodynamically well tolerated, and not associated with symptomatic bradycardia.

CONCLUSIONS

In patients with chronic Chagas cardiomyopathy, optimization of treatment with enalapril and spironolactone and subsequent addition of carvedilol were safe and associated with benefits in cardiac function and clinical status. Larger trials are needed to show effects on mortality and/or hospitalization.

Brain natriuretic peptide based strategy to detect left ventricular dysfunction in Chagas disease: A comparison with the conventional approach

BACKGROUND

Left ventricular dysfunction (LVd) is the main predictor of mortality in Chagas disease (ChD).

AIMS

To compare the diagnostic performance of the conventional approach (ECG and chest X-ray) in the recognition of LVd in ChD, with a new strategy, in which BNP is measured in patients with an abnormal ECG.

METHODS

Consecutive ChD patients recruited at an Outpatient Reference Center in Belo Horizonte, Brazil, without other systemic diseases, in 1998-99 (sample 1, n = 165) and in 2001-02 (sample 2, n = 62) underwent ECG, chest X-ray, BNP measurement and echocardiography.

RESULTS

The prevalence of LVd (ejection fraction <or=0.40) was 9.1% in the sample 1. The conventional strategy recognized all patients with LVd (sensitivity: 100%, 95% CI: 79.6-100% and negative predictive value -PV 100%, 92.1-100%), but with low specificity (30%, 95% CI: 23.2-37.8) and +PV (12.5%, 95% IC: I7.7-19.6). The BNP/ECG strategy showed significantly better specificity (96.0%, 95% CI: 91.5-98.2, p < 0.001) and +PV (66.7%, 95% CI: 43.7-83.7, p < 0.001), and non-significantly lower sensitivity (80.0%, 95% CI: 54.8-93.0, p = 0.25) and -PV (98.0%,95% CI: 94.2-99.3, p = 0.08). Overall accuracy was improved with the new strategy. (94.5%,95% CI: 90.0-97.1 x 36.4%, 95% CI: 29.4-43.9, p < 0.001). Similar results were obtained for the sample 2.

CONCLUSIONS

The BNP-based strategy was more accurate than the conventional approach in the detection of LVd in ChD patients and should be considered as a valid option.