Objective       To determine the therapeutic effect of sildenafil on severe pulmonary arterial hypertension (PAH) associated with congenital heart disease in infants.      Methods      Seventy infants with PAH

38 males and 32 females

with a mean age of 13.2±2.3 months

and a mean weight of  8.4±1.4 kg

hospitalized in our department from January 2009 to November 2010 were enrolled. All t

he 70 infants were randomly divided into research group (n=37) and control group (n=33). There were no significant difference in age

pulmonary artery pressure

p(O

2

)

and SaO

2

between the 2 groups. All infants were treated with diuretic digoxin. Those infants in research group were also treated with Sildenafil（0.5 mg/kg

once per 4 h) and the other of control group were treated with PGE1 [5 ng/(kg·min)

]

. And the changes of pulmonary artery pressure

blood pressure

SaO

2

and p(O

2

) were measured after the drugs were given for 7 to 10 d.      Results     After using Sildenafil for 7 to 10 d

pulmonary artery pressure was decreased (74.6±9.8 mmHg vs 58.3±7.7 mmHg

P0.05)

and p(O

2

) was increased significantly （76.6±7.6 mmHg vs 88.3±5.8 mmHg，P0.05）

and SaO

2

was elevated（76.6±7.6 mmHg vs 88.3±5.8 mmHg

P0.05）. There was no significant change on blood pressure [(92.8±12.3)% vs (93.3±15.6)%

P0.05

]

.  After 7 to 10 days’ treatment

pulmonary artery pressure was obviously alleviated than before treatment in research group.      Conclusion      Sildenafil attenuates pulmonary artery pressure in infants with PAH induced by CHD

and improves the security of operations on those with severe pulmonary hypertension. And sildenafil is cheap

convenient to administration

and should be widely used in clinic.