Early Detection of Cardiac Dysfunction by BNP in Beta-thalassaemia Major Patients

Background: Cardiomyopathy is the leading cause of mortality in beta-thalassaemia major (BTM) patients. Brain natriuretic peptide (BNP) has been used for latent cardiac dysfunction in heart patients other than thalassaemic patients. The objective was to determine its role in subclinical detection of iron-induced cardiotoxicity in BTM patients.

Methods And Results: EDTA plasma was taken from 33 thalassaemic patients and 29 healthy controls, stored at -20 degrees C until analysis. The median (range) age of thalassaemic major children was 10 (6-21) years and mean serum ferritin levels were 3956 (1929-6979) microg/L. The BTM children had significantly (P < 0.01) higher BNP median (range) 83.94 (45.93-196.80) pg/mL as compared to controls 55.62 (32.58-99.84) pg/mL. Mitral E-wave velocities were found higher in patients rather than controls (132.12 +/- 29.40 vs. 117.70 +/- 24.81; P < 0.05). The E/Ea ratio was significantly higher in BTM patients than in the control group (16.35 +/- 6.01 vs. 19.26 +/- 4.67; P = 0.001). We found a significant positive correlation between BNP and E/Ea ratio (r = 0.53; P < 0.01). BNP at a cut-off value of 84.39 pg/mL was highly accurate in ruling out diastolic dysfunction (E/Ea < 8) with a sensitivity of 80% and a specificity of 88%.

Conclusion: BNP has a good predictive value in detecting latent LV dysfunction in BTM patients.