Asymmetric dimethylarginine levels in children with β-thalassemia and their correlations to tricuspid regurgitant jet velocity.

BACKGROUND: Pulmonary hypertension (PHT) may be the leading cause of death in β-thalassemia patients; however, its pathophysiologic mechanisms are still unclear. Recent studies indicate that asymmetric dimethylarginine (ADMA) plays a role in the initiation and progression of a variety of diseases, especially the cardiovascular system. The aim of this study is to assess the levels of ADMA in children with β-thalassemia and their correlations with tricuspid regurgitant jet velocity.

PROCEDURES: This study was carried out on 30 children with β-thalassemia major and 30 healthy children served as a control group. Both groups underwent the following investigations: Blood sampling for CBC, LDH, serum ferritin, reticulocytic count, serum bilirubin, AST, ALT, in addition to plasma levels of ADMA. Doppler echocardiography was done for thalassemic group. Patients with tricuspid regurgitant jet velocity (TRV ≥ 2.5 m/sec) were considered risky for PHT.

RESULTS: Plasma ADMA levels were significantly higher in patients with β-thalassemia than control group with a mean value 0.91 ± 0.14 and 0.62 ± 0.10 µmol/L respectively (P = 0.001). There was a significant positive correlation between plasma ADMA levels and tricuspid regurgitant jet velocity. The prevalence of elevated tricuspid regurgitant jet velocity (TRV ≥ 2.5 m/sec) in patients with thalassemia was 33.3%, with a significant increase of elevated TVR (≥ 2.5 m/sec) in patients with thalassemia with splenectomy than in patients without splenectomy.

CONCLUSION: High plasma ADMA levels may be implicated in the pathogenesis of PHT in children with β-thalassemia.