Related Experiment Videos
Quantitative ultrasonic analysis of myocardium in patients with thalassemia major and iron overload
F Lattanzi1, P Bellotti, E Picano
1Institute of Clinical Physiology, Pisa, Italy.
Insights
Patients with beta-thalassemia major show increased myocardial reflectivity due to iron overload, detectable even when standard heart function tests appear normal. This finding highlights subtle cardiac changes in transfusion-dependent thalassemia.
Area of Science:
- Cardiology
- Biomedical Engineering
- Hematology
Background:
- Beta-thalassemia major necessitates continuous transfusion therapy, leading to iron overload and hemochromatosis.
- Cardiac dysfunction can occur in thalassemia patients, even before clinical heart failure symptoms appear.
- Conventional echocardiography may not detect early cardiac changes in these patients.
Purpose of the Study:
- To assess quantitative acoustic properties of the myocardium in patients with beta-thalassemia major and iron overload.
- To investigate if advanced echocardiographic signal analysis can detect myocardial abnormalities not evident with standard methods.
Main Methods:
- Echocardiography was used to study 38 beta-thalassemia major patients and 20 controls.
- On-line analysis of ultrasonic radiofrequency signals provided operator-independent measurements of integrated backscatter (IB%) in the ventricular septum and posterior wall.
- Conventional echocardiographic parameters like fractional shortening and left ventricular mass index were also assessed.
Main Results:
- Thalassemia patients exhibited significantly higher myocardial reflectivity (IB%) in both septum and posterior wall compared to controls.
- Despite normal fractional shortening, thalassemia patients had a higher left ventricular mass index.
- No significant correlation was found between myocardial reflectivity and hematological parameters or left ventricular mass index.
Conclusions:
- Myocardial reflectivity is abnormally increased in transfusion-dependent beta-thalassemia major patients.
- This increased reflectivity is likely due to myocardial iron deposits and/or secondary structural changes.
- Quantitative assessment of myocardial reflectivity can detect cardiac abnormalities missed by conventional echocardiographic systolic function parameters.
Background:
Patients with beta-thalassemia major present with severe anemia and need continuous transfusion therapy. The consequent iron overload leads to hemochromatosis. Initial cardiac dysfunction has been documented even in thalassemics without clinical manifestations of heart failure as well as by conventional echocardiographic-Doppler techniques. The purpose of this study was to assess the acoustic quantitative properties of myocardium in patients with iron overload.
Methods And Results:
Thirty-eight patients with beta-thalassemia major, without clinical signs of cardiac failure, and 20 age- and sex-matched young controls were studied by echocardiography. An on-line analysis of the ultrasonic radiofrequency signal was performed to obtain quantitative operator-independent measurements of the integrated backscatter (IB) signal of the ventricular septum and the posterior wall. The integrated values of the radiofrequency signal were normalized for the pericardial interface and expressed in percent (IB%). Thalassemic patients had been receiving transfusion therapy for 16 +/- 5 years and had received 313 +/- 138 transfusion units; they all had received chelation treatment (desferroxiamine) for 9 +/- 2 years. Patients and controls showed comparable values of echocardiographically assessed percent fractional shortening (32 +/- 3% versus 36 +/- 4%, p = NS), whereas thalassemics showed higher values of left ventricular mass index (118 +/- 30 versus 98 +/- 15 g/m2, p < 0.05). The IB% values were higher in patients with thalassemia major than in controls for both septum (35 +/- 14% versus 21 +/- 6%, p < 0.001) and posterior wall (16 +/- 6% versus 11 +/- 3%, p < 0.001). In thalassemic patients, no significant correlation was found between the septum IB% value and hematological parameters, such as the total number of transfusions (r = 0.2, p = NS) or the mean ferritin value (r = 0.1, p = NS). No significant correlation was also found between the septum IB% value and the echocardiographically assessed left ventricular mass index (r = 0.2, p = NS).
Conclusions:
These data demonstrate that myocardial reflectivity is abnormally increased in patients with thalassemia major under transfusion treatment, probably due to myocardial iron deposits and/or secondary structural changes. These quantitatively assessed abnormalities in regional reflectivity can be detected when conventional echocardiographic parameters of systolic left ventricular function are undistinguishable from normal controls.