OBJECTIVETo determine the relationship between the serum sulfur dioxide, homocysteine and the pulmonary arterial pressure in children with congenital heart defects who generated a pulmonary arterial hypertension syndrome (PAH-CHD), and analyze their role in the pathological process of the disease.

METHODThis was a prospective cohort study, children with systemic pulmonary shunt CHD were selected. The patients were divided into three groups: the CHD with no PAH group:n = 20, 10 males, 10 females, 5 with ventricular septal defect (VSD), 8 with atrial septal defect (ASD) and 7 with patent ductus arteriosus (PDA), mean age (1.9 ± 1.8) years; the CHD with mild PAH group:n = 20, 10 males, 10 females, 12 with VSD, 6 with ASD, and 2 with PDA, mean age (1.0 ± 0.8) year; the CHD with moderate or severe PAH group:n = 20, 8 males, 12 females, 12 with VSD, 6 with ASD, and 1 with PDA, 1 with ASD+VSD, mean age (1.8 ± 1.6) year. Twenty healthy children were enrolled from outpatient department as the control group [included 8 males, 12 females, mean age (1.9 ± 1.5) years]. The homocysteine and SO2 concentrations in the serum samples were detected by a modified high performance liquid chromatographic method with fluorescence detection (HPLC-FD), then, multiple comparisons among the groups were performed with analysis of variance, and the pearson correlation.

RESULTThe serum homocysteine concentrations were respectively (11.0 ± 2.7) , (11.7 ± 2.5), (12.0 ± 2.1), (14.3 ± 3.2) µmol/L in the control group, CHD with no PAH group, CHD with mild PAH group, and CHD with moderate or severe PAH group. According to the multiple comparisons, the CHD with moderate or severe PAH group had the highest level (P all < 0.05) .While the comparison within the control group, CHD with none PAH group, and CHD with mild PAH group, the differences were not significant (P all > 0.05). The serum sulfur dioxide strength (concentrated as SO3(2-)) were respectively (10.6 ± 2.4), (8.9 ± 2.3), (7.3 ± 2.9), (4.3 ± 2.1) µmol/L in the control group, CHD with none PAH group, CHD with mild PAH group, and CHD with moderate or severe PAH group. CHD with moderate or severe PAH group had the highest level of serum sulfur dioxide (P < 0.05) . The pearson correlation analysis indicated that in the CHD children, the serum homocysteine were positively correlated with the pulmonary arterial pressure (r = 0.481, P < 0.01), while, the sulfur dioxide were negatively correlated with pulmonary arterial pressure (r = -0.553, P < 0.01).In all children, the serum homocysteine levels were negatively correlated with the sulfur dioxide (r = -0.231, P = 0.039).

CONCLUSIONThe PAH-CHD children had higher homocysteine levels and lower sulfur dioxide levelsl, which demonstrated the disturbance of homocysteine-sulfur dioxide pathway in the sulfur containing amino acids metabolish in the disease. The homocysteine may become a biological marker which reflecting the severities of the PAH-CHD, while the sulfur dioxide can be a new target for the therapy of PAH-CHD.