Correlation of N-terminal pro-B-type natriuretic peptide levels and cardiac magnetic resonance imaging T2* in patients with β-thalassaemia major.

BACKGROUND

Cardiac death secondary to myocardial iron toxicity occurs in 50% of patients with transfusion-dependent β-thalassaemia major. N-terminal pro-B-type natriuretic peptide (NT-proBNP) seems to be a useful tool for early detection of cardiac haemosiderosis. We designed this study to determine whether plasma NT-proBNP levels are predictive of cardiac iron concentration, based on heart T2* assessment by magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We evaluated plasma NT-proBNP levels in 50 patients with β-thalassaemia major, aged 18 to 46 years, with preserved left ventricular systolic function, all of whom had undergone cardiac MRI within 3 months before the study. Next, three groups were defined based on heart T2* value as: group A, patients without evidence of cardiac iron overload (T2*>20 ms); group B, patients with mild to moderate cardiac iron overload (10 ms<T2*<20 ms); group C, patients with severe cardiac iron overload (T2*<10 ms).

RESULTS

NT-proBNP level was not similar among the three groups (p=0.03), being significantly higher in patients in group C (1,104.2±350.5 pg/mL) than in patients in group B (565.9±116.9 pg/mL, p=0.03) or group A (563.5±162.5 pg/mL, p=0.04). The analyses indicate that NT-proBNP levels did not correlate with cardiac iron concentrations (r=0.152, p=0.148).

DISCUSSION

Based on our study, measurements of NT-proBNP levels are not sufficient for early detection of cardiac iron overload. However, NT-proBNP measurements might be used as a tool to guide iron chelation therapy in patients with severe cardiac iron overload. The determination of their clinical use still requires multicentre studies.