The objectives of this study were to evaluate the plasma levels of asymmetric dimethyl-L-arginine in children with pulmonary hypertension due to CHD before and after treatment with sildenafil and to evaluate its diagnostic and prognostic value as a biomarker in such children.

A total of 60 children with CHD and 30 healthy control children matched for age and sex were recruited. Children with CHD were divided into two equal groups: the normal pulmonary pressure group (n=30) and the pulmonary hypertension group (n=30). Children with pulmonary hypertension were treated with sildenafil and were followed up for 6 months. Clinical data, haemodynamic parameters, echocardiographic examination, and asymmetric dimethyl-L-arginine levels were evaluated before and after treatment.

Asymmetric dimethyl-L-arginine levels were significantly higher in patients with pulmonary hypertension than in those with CHD-only or the control group, and this increase was positively correlated with increased severity of pulmonary hypertension. Asymmetric dimethyl-L-arginine levels, mean pulmonary artery pressure, and pulmonary vascular resistance were significantly decreased after treatment with sildenafil. Moreover, asymmetric dimethyl-L-arginine level was significantly lower in patients who responded to sildenafil treatment compared with those who did not. At a cut-off point of more than 0.85 nmol/ml, asymmetric dimethyl-L-arginine has a sensitivity of 83% and a specificity of 80% to diagnose pulmonary hypertension-CHD. Asymmetric dimethyl-L-arginine has a sensitivity of 100% and a specificity of 94% to predict poor prognosis in pulmonary hypertension-CHD children at a cut-off point of 1.3 nmol/ml.

Asymmetric dimethyl-L-arginine level has a good diagnostic and prognostic value as a biomarker in children with pulmonary hypertension-CHD and can be used for following up patients with pulmonary hypertension and predicting response to treatment.