Comparison of Doppler echocardiographic and tissue Doppler velocity data in beta-thalassaemia major with high and normal NT-proBNP levels of children in the south-east region of Turkey.

Background: It has been reported that N-terminal pro-brain natriuretic peptide (NT-proBNP) is early biomarker of iron- induced cardiomyopathy in β-thalassemia major (β-TM). In this study, we aimed to assess the Doppler echocardiographic, tissue Doppler velocity datas and clinical characteristics in β-TM patients with high and normal NT-proBNP levels who have normal systolic function.

Material And Method: Fifty-eight β-TM patients who were on regular transfusion in every 3-4 weeks for more than one year and 20 healthy children were included into the study. According to NT-proBNP levels, β-TM patients are divided in two groups. Group I: the patients with high NT-proBNP levels; Group II: the patients with normal NT-proBNP levels.

Results: The mean serum NT-proBNP levels were significantly increased in patients with β-TM compared to control group (P<0.05). The serum ferritin levels were ranged between 676-9,476 ng/mL (mean: 3,716±2,003 ng/mL) in β-TM. No correlation was found between ferritin and NT-pro BNP in patients with β-TM. The mean age and body surface area (BSA) were significantly low in group with high NT-proBNP compared to group with normal NT-proBNP (P<0.01). The mean heart rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were elevated, but not significantly in group with high NT-proBNP. Also, the mean ferritin and hemoglobin levels were decreased in this group compared to group with normal NT-proBNP, but statistically not significant. The left ventricular end diastole (LVED) diameters and left ventricular mass index (LVMI) values were found significantly decreased in group with high NT-proBNP compared to other group respectively (P<0.001, P<0,05). Right ventricular early diastolic tricuspid inflow velocity/early diastolic tissue Doppler indices (TDI) tricuspid annular velocity (RV E/E') were found increased in group with high NT-proBNP levels and difference was statistically significant (P<0.05). In addition, NT-pro BNP was found correlated with RV E/E' (r: 0.320).

Conclusions: According to our result, elevated NT-proBNP level was correlated with RVE/E', but it was not associated with ferritin level. The serum NT-proBNP level may be increased as a response to increased myocardial workload and decreased hemoglobin level in patients who have an increased need for transfusion.