Role of adrenomedullin in congenital heart disease associated with pulmonary hypertension

The changes of adrenomedullin (ADM), endothelin-1 (ET-1) and nitric oxide (NO) levels before and after operation in congenital heart disease (CHD) associated with pulmonary hypertension (PH) were observed in order to investigate their role in CHD with PH and their clinical significance. The CHD patients were divided into 3 groups according to pulmonary artery systolic pressure (PASP); Non-PH group: PASP≤30 mmHg (n=11); mild-PH group; PASP 31–49 mmHg (n=10); moderate or severe-PH group: PASP≥50 mmHg (n=12). The control group consisted of 15 health children. Plasma ADM, ET-1 and NO levels were determined by radioimmunoassay and colorimetry methods. The correlation between ADM and ET-1, NO, PASP was analyzed. The changes in plasma ADM, ET-1 and plasma NO on the 7th day after operation among the groups were compared. The results showed that plasma ADM levels in non-PH group were significantly higher than that in control group (P<0.05), but there was no significant difference in ET-1 and NO levels between the two groups (P>0.05). ADM and ET-1 levels in mild-PH group were significantly elevated as compared with those in non-PH group (bothP<0.05), but NO levels were decreased (P<0.05). ADM and ET-1 levels in moderate or severe-PH groups were increased as compared with those in mild-PH group (bothP<0.01), but NO level significantly declined (P<0.05). On the 7th day, after operation, plasma ADM and ET-1 levels in PH group were significantly decreased (P<0.05,P<0.01) as compared with those before operation, but there was no significant difference in NO levels (P>0.05). But NO levels in non-PH group were significantly increased (P<0.05). Plasma ADM, levels in CHD were positively correlated with PASP and ET-1 (r=0.77,P<0.01;r=0.82,P<0.01), negatively correlated with NO (r=−0.56,P<0.05). It was concluded that during the progression of PH in the cases of CHD, plasma ADM, ET-1 and NO might play an important role in the development of PH. The increased ADM may represent a compensatory mechanism. It can interact with NO and ET-1 to regulate pulmonary circulation in the pathophysiology of PH with CHD. ADM may be involved in the defence mechanism against further increase of pulmonary arterial pressure. ADM could be used as a reliable indicator of the severity of CHD associated PH.