Intro: Thalassemia Major (TM) is characterized by recurrent blood transfusions leading to myocardial siderosis and complications including arrhythmias and heart failure. These can be reversible with adequate chelation. We explored the effect of improved chelation and subsequent cardiac T2* MRI (CMR) values on regional myocardial function assessed by 2D STE in setting of normal LVEF.
Methods: Data was derived from TM patients recruited for the AMIT study (efficacy of amlodipine with chelation in reducing myocardial iron). All patients underwent echocardiographic imaging at baseline, 6 and 12 months. LSsys was extracted from basal, mid, and apical segments of the LV medial and lateral wall by 2D STE technique. A linear regression model was run to determine the effect of improved T2* in the setting of improved chelation on regional LSsys strain parameters.
Results: Nineteen TM patients (11 males), median age 16 (8-21) yrs. All participants were transfused every 2-3 weeks. (median pre-transfusional Hb of 9.3 (8.3-10.8) mg/dL). T2* based chelation regimen was initiated at baseline and compliance to this regimen was gauged at regular clinical visits. 25 data points were available from interval 2D STE imaging for analysis. Medial basal LSsys (-17.3% ± 2.2) and lateral basal LSsys (-16.7% ± 4.4) strains were significantly lower than mean apical LSsys strains (-24.9% ± 4.0) (p <0.01). With optimized improved chelation, we determined up to a 6.3% improvement was seen in LSsys basal septal and 6.7% improvement in LSsys apical septal for each 1 ms improvement in T2* (p values < 0.05).
Conclusion: 2D STE can help identify regional myocardial dysfunction prior to development of overt cardiac dysfunction. In patients with transfusion dependent TM, compliance to an optimized chelation regimen can help improve regional myocardial function prior to progression to systolic dysfunction and clinically symptomatic sideroblastic complications.