Electrocardiographic Abnormalities and Treatment with Benznidazole among Children with Chronic Infection by Trypanosoma cruzi: A Retrospective Cohort Study

Long-term cardiology outcomes in children after early treatment for Chagas disease, an observational study

BACKGROUND

Parasite persistence after acute infection with Trypanosoma cruzi is an important factor in the development of Chagas disease (CD) cardiomyopathy. Few studies have investigated the clinical effectiveness of CD treatment through the evaluation of cardiological events by long term follow-up of treated children. Cardiological evaluation in children is challenging since features that would be diagnosed as abnormal in an adult's ECG may be normal, age-related findings in a pediatric ECG trace. The objective was to evaluate cardiac involvement in patients with Chagas disease with a minimum follow-up of 6 years post-treatment.

METHODOLOGY

A descriptive study of a cohort of pediatric patients with CD treated with benznidazole (Bz) or nifurtimox (Nf) was conducted. Children (N = 234) with at least 6 years post CD treatment followed at the Parasitology and Chagas Service, Buenos Aires Children's Hospital (Argentina) were enrolled. By convenience sampling, children who attended a clinical visit between August 2015 and November 2019 were also invited to participate for additional cardiovascular studies like 24-hour Holter monitoring and speckle-tracking 2D echocardiogram (STE). Benznidazole was prescribed in 171 patients and nifurtimox in 63 patients. Baseline parasitemia data was available for 168/234 patients. During the follow-up period, alterations in routine ECG were observed in 11/234 (4.7%, 95% CI [2-7.4%]) patients. In only four patients, with complete right bundle branch block (cRBBB) and left anterior fascicular block (LAFB), ECG alterations were considered probably related to CD. During follow-up, 129/130 (99%) treated patients achieved persistent negative parasitemia by qPCR. Also decrease in T.cruzi antibodies titers was observed in all patients and negative seroconversion occurred in 123/234 (52%) patients.

CONCLUSIONS

A low incidence of cardiological lesions related to CD was observed in patients treated early for pediatric CD. This suggests a protective effect of parasiticidal treatment on the development of cardiological lesions and highlights the importance of early treatment of infected children.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04090489.

Trypanocidal therapy among children infected by Trypanosoma cruzi. Serological and electrocardiographic changes over a mean twenty-five-years follow-up period

This study compared the serological and electrocardiographic evolution among patients with chronic T. cruzi infection treated during childhood or left untreated. A retrospective cohort study was conducted during a mean follow-up period of 25 years in 82 patients: half of them underwent treatment (nifurtimox 8, benznidazole 33) before being 15 years old, whereas the other half remained untreated. During the follow-up, negative seroconversion occurred in 92.7% of the treated children, while all the untreated ones remained positive for conventional serology. At baseline, 2 patients from each group had electrocardiographic abnormalities. During the study period, 4/41 (9.75%) and 9/41 (21.95%) of treated and untreated patients displayed an altered electrocardiogram, respectively. In multivariate analyses, the probability of developing electrocardiographic abnormalities was significantly reduced among treated patients (OR = 0.18, 95% CI = 0.04-0.79; p = 0.023). Electrocardiographic abnormalities attributable to Chagas cardiomyopathy were seen in 3 patients from the untreated group (complete right bundle branch block + left anterior fascicular block, frequent ventricular extrasystole, and left anterior fascicular block). The remarkable seronegativization seen in Benznidazole and Nifurtimox recipients underlines the parasiticidal effect of both compounds. Such demonstration along with the fact that CCC-related alterations were only present in the untreated group, reinforces the view of trypanocidal treatment in chronically T. cruzi-infected children as decreasing the risk for cardiomyopathy development.

A Rapid Review on the Efficacy and Safety of Pharmacological Treatments for Chagas Disease

Chagas disease remains a neglected tropical disease, causing significant burden in the Americas and countries that receive immigrants from endemic nations. Current pharmaceutical treatments are suboptimal, not only varying drastically in efficacy, depending on the stage of disease, but also presenting significant risk of adverse events. The objective of this review is to provide a timely update on the efficacy and safety of current trypanocidals. Eligible studies published from January 2015 to December 2020 were retrieved by one reviewer from six electronic databases. Ana-lysis was done with review management software and risk of bias was assessed using tools appropriate for the type of study (i.e., experimental or observational). Thirteen studies (10 observational and three RCTs) were included in the analysis. All 13 studies tested Benznidazole (BNZ) or Nifurtimox (NFX), and two studies also tested Posaconazole (POS) or E1224 (Ravucanazole). BNZ was found to be the most efficacious trypanocidal drug compared to Nifurtimox, POS, and E1224; it also resulted in the highest percentage of adverse effects (AEs) and treatment discontinuation due to its toxicity. Adults experienced higher frequency of neurological AEs while taking BNZ or NFX compared to children. Children had a higher frequency of general AEs compared to adults while taking BNZ. Overall, BNZ is still the most efficacious, but development of new, less toxic drugs is paramount for the quality of life of patients. Studies testing combination therapies and shorter regimens are needed, as is the devising of better clinical parameters and laboratory biomarkers to evaluate treatment efficacy. Considering the variability in methodology and reporting of the studies included in the present analysis, we offer some recommendations for the improvement and replicability of clinical studies investigating pharmacological treatment of Chagas disease. These include full disclosure of methodology, standardization of outcome measures, and always collecting and reporting data on both the efficacy of trypanocidals and on safety outcomes.

Risk of Chronic Cardiomyopathy Among Patients With the Acute Phase or Indeterminate Form of Chagas Disease: A Systematic Review and Meta-analysis

Importance

Chagas cardiomyopathy is associated with substantial morbidity and mortality. Precise estimates of the risk of developing cardiomyopathy among patients with the acute or indeterminate chronic forms of Chagas disease are lacking.

Objective

To estimate the risk of developing chronic cardiomyopathy in patients with acute and indeterminate chronic forms of Chagas disease.

Data Sources

A systematic search in the Cochrane Library, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), Medline, and Web of Science Core Collection databases was conducted from October 8 to October 24, 2018. Studies published between January 1, 1946, and October 24, 2018, that were written in the English, Spanish, and Portuguese languages were included. Search terms included Chagas disease; development of cardiomyopathy; latency duration; and determinants of the Chagas latency period.

Study Selection

Longitudinal observational studies of participants diagnosed with the acute phase of Chagas infection or the indeterminate chronic form of Chagas disease who were followed up until the development of cardiomyopathy were included. Studies were excluded if they did not provide sufficient outcome data. Of 10 761 records initially screened, 32 studies met the criteria for analysis.

Data Extraction and Synthesis

Critical appraisals of studies were performed using checklists from the Joanna Briggs Institute Reviewer's Manual, and data were collected from published studies. A random-effects meta-analysis was used to obtain pooled estimated annual rates. Data were analyzed from September 11 to December 4, 2019. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline for the registration of the protocol, data collection and integrity, assessment of bias, and sensitivity analyses.

Main Outcomes and Measures

Main outcomes were defined as the composite of the development of any new arrhythmias or changes in electrocardiogram results, dilated cardiomyopathy and segmental wall motion abnormalities in echocardiogram results, and mortality associated with Chagas disease.

Results

A total of 5005 records were screened for eligibility. Of those, 298 full-text articles were reviewed, and 178 of those articles were considered for inclusion in the quantitative synthesis. After exclusions, 32 studies that included longitudinal observational outcomes were selected for the analysis; 23 of those studies comprised patients with the indeterminate chronic form of Chagas disease, and 9 of those studies comprised patients in the acute phase of Chagas infection. The analysis indicated that the pooled estimated annual rate of cardiomyopathy development was 1.9% (95% CI, 1.3%-3.0%; I2 = 98.0%; τ2 [ln scale] = 0.9992) in patients with indeterminate chronic Chagas disease and 4.6% (95% CI, 2.7%-7.9%; I2 = 86.6%; τ2 [ln scale] = 0.4946) in patients with acute Chagas infection.

Conclusions and Relevance

Patients with the indeterminate chronic form of Chagas disease had a significant annual risk of developing cardiomyopathy. The annual risk was more than double among patients in the acute phase of Chagas infection.

The Clinical and Parasitologic Follow-up of Trypanosoma cruzi-infected Children in a Nonendemic Country

BACKGROUND

Chagas disease has become a global health problem, with the pediatric population being especially vulnerable. Our aim was to describe the clinical-epidemiologic aspects of disease in this population, as well as tolerance and adherence to treatment and the subsequent evolution of the disease.

METHODS

A prospective study involving 949 children 0-14 years of age screened from 2007 to 2018. Diagnosis was performed by polymerase chain reaction and/or microhematocrit in <1-year-old children or serology in those ≥1 year of age. After diagnosis, children were examined for the clinical manifestation of Chagas disease and were treated with benznidazole. Treatment response was monitored by polymerase chain reaction and serology.

RESULTS

Forty children were infected (4.2% of the population screened). Twelve children were diagnosed during the acute phase (≤1-year-old), 3 of whom were symptomatic, and 28 (4- to 14-year-olds) were in the chronic phase: 18 in the indeterminate phase and 10 presented cardiac and/or digestive involvement. Regarding treatment, 10 (25.6%) children had side effects (6 mild, 2 moderate and 2 severe reactions), leading to treatment interruption in 3 of them. No side effects were detected in ≤1-year-old children (P < 0.05). Cure was confirmed in 29.4% of the children during follow-up, and the age of the children at treatment (≤1 year) was clearly associated with the effectiveness of treatment (P < 0.05).

CONCLUSIONS

Effectiveness and safety of treatment were optimum in ≤1-year-old children. Increased side effects, cardiac and/or digestive disorder incidence and lower treatment effectiveness were detected in older children, highlighting the need for early screening.

Progression of Baseline Electrocardiogram Abnormalities in Chagas Patients Undergoing Antitrypanosomal Treatment

Background

The objective of the study was to better understand the impact of antitrypanosomal treatment on the evolution of Chagas-related, prognostically important electrocardiogram (ECG) abnormalities.

Methods

Initial and posttreatment ECGs were obtained in a prospective cohort of Chagas patients treated with nifurtimox or benznidazole and compared to an untreated cohort. Electrocardiogram disease progression was compared in those with and without baseline abnormalities pre- and posttherapy.

Results

Fifty-nine patients were recruited in the treatment arm and followed for an average of 3.9 years. There were no differences between ECG groups with regards to follow-up, age, baseline ejection fraction, or therapy. In the treated cohort, 0 of 30 patients with normal ECGs developed an abnormal ECG compared with 7 of 29 patients with baseline ECG abnormalities who developed new ECG abnormalities (P = .005). In an untreated cohort of 30 patients, 3 of 7 with normal ECGs developed an abnormality compared with 14 of 23 patients with baseline abnormalities (P = .67). Untreated patients had a higher likelihood of developing new EKG abnormalities (56.7% vs 11.9%, P < .001) despite shorter follow-up, and in a multivariate analysis adjusting for baseline EKG status across both treated and untreated cohorts, treated patients were still less likely to have progression of their EKG disease (odds ratio = 0.13, P < .001). The corrected QT (QTc) interval was not significantly affected by either study medication (415 vs 421 ms, initial vs posttreatment QTc; P = .06).

Conclusions

Over an average follow-up of 3.9 years, treated patients with normal baseline ECGs did not have significant changes during a course of treatment; however, those with baseline abnormal ECGs had significant progression of their conduction system disease despite treatment, and those without treatment also experienced a progression of ECG disease. These preliminary results suggest that Chagas patients with normal ejection fraction and normal ECG may benefit the most from antitrypanosomal treatment.

Parasitaemia and parasitic load are limited targets of the aetiological treatment to control the progression of cardiac fibrosis and chronic cardiomyopathy in Trypanosoma cruzi-infected dogs

It is still unclear whether the progression of acute to chronic Chagas cardiomyopathy is predominantly associated with the limited efficacy of aetiological chemotherapy, or with the pharmacological resistance profiles and pathogenicity of specific Trypanosoma cruzi strains. Thus, we tested the hypothesis that parasitic load could be a limited target of aetiological chemotherapy to prevent chronic cardiomyopathy in dogs infected by different T. cruzi strains. Animals were infected with benznidazole-susceptible (Berenice-78) and -resistant (VL-10 and AAS) strains of T. cruzi. A quantitative real-time PCR strategy was developed to comparatively quantify the parasite load of the three different strains using a single standard curve. For dogs infected with the VL-10 strain, benznidazole treatment reduced cardiac parasitism during the acute phase of infection. However, similar parasite load and collagen deposition were detected in the myocardium of treated and untreated animals in the chronic phase of the infection. In animals infected with the AAS strain, benznidazole reduced parasite load, myocarditis and type III collagen deposition in the acute phase. However, increased type III collagen deposition was verified in the chronic phase. Dogs infected with the Berenice-78 strain showed a parasitological cure and no evidence of myocardial fibrosis. Parasitic load and cardiac fibrosis presented no correlation in acute or chronic phases of T. cruzi infection. Our findings in a canine model of Chagas disease suggest that parasite burden is a limited predictor for disease progression after treatment and show that benznidazole, although not inducing parasitological cure, is able to prevent total fibrosis in the early stages of infection, as well as complete prevention of cardiac damage when it eliminates parasites at the onset of infection.

Scientometrics analysis of research activity and collaboration patterns in Chagas cardiomyopathy

Background

Chagas cardiomyopathy is a serious and common complication of Chagas disease.

Methods

Through bibliometric and Social Network Analysis, we examined patterns of research on Chagas cardiomyopathy, identifying the main countries, authors, research clusters, and topics addressed; and measuring the contribution of different countries.

Results

We found 1932 documents on Chagas cardiomyopathy in the MEDLINE database. The most common document type was ‘journal article’, accounting for 79.6% of the total (n = 1538), followed by ‘review’ (n = 217, 11.2%). The number of published records increased from 156 in 1980–1984 to 311 in 2010–2014. Only 2.5% were clinical trials. Brazil and the USA dominated the research, participating in 53.1% and 25.7%, respectively, of the documents. Other Latin American countries where Chagas is endemic contributed less, with Bolivia, where Chagas disease is most prevalent, producing only 1.8% of the papers. We observed a high rate of domestic collaboration (83.1% of the documents published in 2010–2016) and a lower but significant rate of international collaboration (32.5% in the same time period). Although clinical research dominated overall, the USA, Mexico and several countries in Europe produced a considerable body of basic research on animal models. We identified four main research clusters, focused on heart failure and dysfunction (physical symptoms, imaging techniques, treatment), and on myocarditis and parasitemia in animal models.

Conclusions

Research on Chagas cardiomyopathy increased over the study period. There were more clinical than basic studies, though very few of the documents were clinical trials. Brazil and the USA are currently leading the research on this subject, while some highly endemic countries, such as Bolivia, have contributed very little. Different approaches could help to redress this imbalance: encouraging researchers to conduct more clinical trials, launching international collaborations to help endemic countries contribute more, and strengthening links between basic and clinical research.

Scientific production on Chagas cardiomyopathy has grown considerably since the turn of the 21st century, probably reflecting the increased incidence of Chagas disease in non-endemic areas like the USA and Europe. Brazil and the USA dominate the research, but we found a very small proportion of clinical trials on Chagas cardiomyopathy and a low scientific production in several endemic countries with a high prevalence of the disease such as Colombia, Chile, Mexico and Bolivia. We observed a polarity between endemic and non-endemic countries where clinical research and basic research predominate, respectively. Different approaches could help to redress the observed imbalance of research on Chagas cardiomyopathy: encouraging researchers to conduct more clinical trials, launching international collaborations to help endemic countries contribute more, and strengthening links between basic and clinical research. It is crucial to foster translational research in order to link basic knowledge on the physiology of the disease with clinical applications in diagnosis and treatment.

Fresh insights into the pyrimidine metabolism in the trypanosomatids

The trypanosomatid parasites continue their killing spree resulting in significant annual mortality due to the lack of effective treatments and the prominence of these diseases in poorer countries. These dimorphic parasites thrive unchecked in the host system, outsmarting the immune mechanisms. An understanding of biology of these parasitic forms will help in the management and elimination of these fatal diseases. Investigation of various metabolic pathways in these parasites has shed light in the understanding of the unique biology of the trypansomatids. An understanding of these pathways have helped in tracing the soft targets in the metabolic pathways, which could be used as effective drug targets which would further impact the therupeutic implications. Pyrimidine pathway is a vital metabolic pathway which yields in the formation of pyrimidines, which are then integrated in nucleic acids (DNA and RNA) in sugars (UDP sugars) and lipids (CDP lipids). A wealth of data and information has been generated in the past decades by in-depth analyses of pyrimidine pathway in the trypanosomatid parasites, which can aid in the identification of anomalies between the parasitic and host counterpart which could be further harnessed to develop therapeutic interventions for the treatment of parasitic diseases. This review presents an updated and comprehensive detailing of the pyrimidine metabolism in the trypansomatids, their uniqueness and their distinctions, and its possible outcomes that would aid in the eradication of these parasitic diseases.