Myocardial longitudinal strain as the first herald of cardiac impairment in very early iron overload state: an echocardiography and biosusceptometry study on beta-thalassemia patients

Background: Heart diseases due to iron overload are still the main cause of mortality in patients affected by beta-thalassemia. Detection of cardiac iron overload in pre-clinical stage allows tailoring of chelation therapy and follow-up strategies. Echocardiographic longitudinal strain analysis may be a useful tool for early detection of cardiac functional impairment iron-related. Methods: We examined 58 patients with beta-thalassemia on regular blood transfusion and iron chelation, without overt cardiac disease who had recent Biosusceptometry SQUID to quantify liver iron concentration and cardiac assessment by CMR T2*. Results: Average global longitudinal strain (GLS) was able to identify abnormal (<20 ms) cardiac T2* values with 96% specificity and negative predictive value of 92% (AUC 0.84, P=0.01). Apical 4-ch GLS may help identify early longitudinal impairment associated with severe liver iron overload with 96% specificity and negative predictive value of 92% (AUC 0.84, P=0.02). Patients with severe liver iron overload had lower average Global Longitudinal Strain values compared to other patients (P-value =0.005). Conclusion: GLS was a sensitive marker to detect both myocardial and liver iron overload in a population that is still free from cardiac symptoms. Thus, strain echocardiography may be a useful tool for early detection of iron overload in Beta-thalassemia.