A study evaluated 77 people for 3 years and showed that analyzing the deformation of the myocardium during its contraction allows concluding a risk of death
A simple imaging test, capable of evaluating myocardial deformation during its contraction, appears as a promising tool for predicting the risk of cardiac complications in patients with chronic Chagas disease.
The study, conducted by researchers from USP (University of São Paulo) in Ribeirão Preto, in partnership with researchers from Duke University and Yale (both in the United States), highlights the index global longitudinal strain (GLS) –already used in other diseases and conditions– as a sensitive and independent marker to predict outcomes in chronic chagasic cardiomyopathy. The results were in the magazine PLOS Neglected Tropical Diseases.
Chronic Chagas cardiomyopathy is one of the main consequences of Chagas disease in its chronic phase. Caused by the parasite Trypanosoma cruzithe condition progressively damages heart tissue, leading to inflammation, scarring (fibrosis), and heart failure. Even after the acute phase, the infection can progress silently for decades, until it causes serious complications such as arrhythmia, embolism and sudden death.
The Strain technique is an advanced echocardiography method that allows measuring GLS by tracking bright points in the cardiac image (speckle tracking). With this index, it is possible to identify whether the myocardium is deforming appropriately during its systole (contraction), a crucial sign for detecting damage to cardiac tissue even before it becomes evident in the form of fibrosis.
“When the myocardium is not deforming well, it suggests that there is fibrosis in the tissue. Therefore, although GLS does not directly visualize fibrosis in the heart tissue, it predicts its presence between the muscle cells of the heart [miócitos]which signals a high risk of future complications”explains, professor at the Faculty of Medicine of Ribeirão Preto at USP.
In the study, by Fapespechocardiography exams of 77 patients with chronic chagasic heart disease, followed for approximately 3 years, were analyzed. In the study, patients were divided into 3 groups according to GLS values, and the outcomes evaluated included death, hospitalizations, sustained ventricular tachycardia, new cases of heart failure and cardioembolic events.
The results showed that patients with GLS greater than or equal to -13.8% (more compromised) had a worse prognosis, with a higher incidence of deaths and complications. According to the researchers, even after adjustments for age, sex and left ventricular ejection fraction (percentage of blood pumped by the left ventricle with each beat), GLS remained an independent predictor of risk, with statistical significance.
“This technique is already used in several other heart diseases, such as in cancer patients to monitor attacks on the heart caused by chemotherapy, such as in cases of breast cancer. Now, the study suggests that the same method can be applied to track the evolution of Chagas disease, especially in places where diagnosis is rarely carried out, such as in geographic regions with low prevalence of the disease”explains the researcher to Fapesp Agency.
Romano highlights that previous studies have already validated other indices for the early detection of cardiac complications resulting from Chagas disease, but had not yet proven the role of GLS as an independent prognosticator.
One of the ways to predict the risk of chronic Chagas heart disease that has already been validated is the Rassi score. Developed by a Brazilian researcher, the score evaluates six variables to predict the long-term prognosis of a patient with Chagas disease. “It has already been validated, but it still leaves a margin of risk between intermediate cases, that is, those that are not classified as high or low risk”says the researcher.
For the detection of myocardial fibrosis, the most accurate method is cardiac magnetic resonance imaging with contrast (gadolinium). However, it is an expensive test that is not widely available and can cause discomfort in patients with claustrophobia.
Echocardiography using GLS is cheaper, can be repeated as many times as necessary and applied on a large scale. “It is a risk marker that can have broad applicability, especially in places where the diagnosis of Chagas heart disease is still rare”reinforces Romano.
Despite the good news, there are still challenges to implementing GLS on a large scale. Although accessible, the technique requires technical knowledge and specialized interpretation. “The technique is more complex than conventional laboratory tests, such as biochemical measurements. Still, it represents a relevant advance in risk stratification and in monitoring the evolution of chronic chagasic heart disease, offering health professionals a powerful tool for more accurate clinical decisions”concludes Romano.
The article “Global longitudinal strain as a predictor of outcomes in chronic Chagas’ cardiomyopathy” can be read.
With information from .
