In a study including asymptomatic children with beta-thalassemia major, researchers found that a feature visible in cardiac imaging called longitudinal strain (LS), in combination with conventional transthoracic echocardiography (TTE) parameters, may help identify subclinical myocardial dysfunction associated with iron overload. The study results were reported in the International Journal of Cardiovascular Imaging.
Blood transfusions in patients with beta-thalassemia major have potential to cause iron overload in multiple organs. In the heart, excess iron accumulation can lead to cardiac dysfunction and morbidity and mortality. Subclinical dysfunction of the left ventricle can be difficult to detect with conventional TTE parameters, so the researchers aimed to determine if analyzing LS could potentially help identify subclinical cardiac dysfunction in this patient population.
This observational, prospective, multicenter study enrolled patients with beta-thalassemia major who were at or below 18 years of age and receiving care in tertiary care facilities in Tunisia. Patients also had received repeated blood transfusions since the age of 6 months and chelation therapy based on serum ferritin levels.
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The researchers investigated multiple conventional TTE parameters and regional LS in in patients for estimating left ventricle iron overload. LS was evaluated using speckle tracking echocardiography. The researchers also performed analyses with a population of control individuals without thalassemia matched to the patient population by various characteristics.
Overall, there were 60 children included in this study. Among patients with beta-thalassemia major, there were 20 boys and 10 girls, and these patients had a mean age of 10.4 + 5 years. Patients with beta-thalassemia major all were of functional Class I based on New York Hearth Association criteria and they had a mean serum ferritin level of 2944.6 + 2333.8 mg/L. Patients with beta-thalassemia major had higher systolic blood pressure than the control group did (P <.01), but diastolic blood pressure was not statistically different between groups.
Across several TTE parameters, there were not significant differences detected between the study population with beta-thalassemia major and the control group. These parameters included left ventricular end systolic diameter and end diastolic diameter, left ventricular end systolic and end diastolic volumes, left ventricle wall thickness, systolic pulmonary artery pressure, and other features. However, compared with the control group, children with beta-thalassemia major had significantly higher values for indexed left atrial volume (P =.001) and indexed right atrial volume (P =.003).
Patients with beta-thalassemia major showed significantly reduced regional LS in anterior, septal, and inferior walls in the basal and middle left ventricle segments, compared with the control group, and similar lateral regional LS.
In the patients with beta-thalassemia major, the researchers considered the reduced regional LS in basal, middle anterior, and septal segments to suggest regional left ventricular dysfunction. Serum ferritin levels did not correlate with various cardiac parameters studied.
The researchers concluded that evaluation of LS appeared predictive of clinically silent myocardial dysfunction. Additionally, they suggested there may be a role for routine analysis of LS in cardiac work-up of asymptomatic patients with beta-thalassemia major.
Reference
Chamtouri I, Khalifa R, Besbes H, et al. Cardiac iron overload detection using longitudinal strain in asymptomatic children with beta thalassemia major. Int J Cardiovasc Imaging. 2022;38(11):2283-2290. doi:10.1007/s10554-022-02597-w
