Early identification of cardiovascular involvement in patients with β-thalassemia major

The aim of the present study was to evaluate left ventricular myocardial deformation and carotid arterial stiffness using 2-dimensional strain and echo-tracking in patients with asymptomatic β-thalassemia major (β-TM) without significant myocardial iron overload to determine whether early subclinical cardiovascular abnormalities would be detectable. We enrolled 32 patients with β-TM (23 women, mean age 35 ± 8 years) and 33 healthy volunteers (20 women, mean age 35 ± 6 years). All subjects underwent echocardiography with 2-dimensional strain analysis (XStrain) and ultrasonography of the carotid arteries with measurement of the stiffness parameters (ProSound Alpha 10). Cardiac magnetic resonance imaging using a T2* algorithm (37.7 ± 5.6 ms) for the assessment of myocardial iron overload was performed in each patient. The clinical and standard echocardiographic parameters were comparable between the patients and healthy subjects. The global left ventricular longitudinal strain was significantly impaired in the patients compared with the controls (-17.9 ± 3.5% vs -24.3 ± 3.4%, p = 0.002), although the radial and circumferential strain values were similar between the 2 groups (p = NS for both). The carotid intima-media thickness was comparable between the patients and healthy subjects (0.67 ± 0.20 mm vs 0.66 ± 0.15 mm, p = NS). In contrast, the arterial stiffness was significantly increased in the patients compared with the controls (stiffness index 6.16 ± 1.31 vs 4.65 ± 0.82, p <0.001; arterial compliance 1.10 ± 0.26 vs 1.28 ± 0.30 cm(2)/mm Hg, p = 0.027; elastic modulus 74.1 ± 19.5 vs 59.1 ± 12.1 mm Hg, p = 0.001). In conclusion, cardiovascular abnormalities, although often subclinical, occur at an early stage of β-TM and also in the absence of significant iron overload. Thus, 2-dimensional strain and echo-tracking might be more accurate than standard echocardiography and vascular parameters in the early identification of cardiovascular involvement.