The objective of this study was to assess the efficacy and appropriate dose of iloprost for inhalation in the treatment of postoperative pulmonary hypertension in children with congenital heart defects.

Pulmonary hypertension is a serious postoperative complication in children with congenital heart defects, which has a high incidence and mortality. Iloprost is a prostacyclin analogue. When applied by inhalation, it selectively dilates pulmonary vessels, without side affecting the systemic circulation. No randomized controlled trials (RCT) of iloprost have previously been performed in this indication. The investigators study is the first RCT of iloprost for inhalation after surgery of children's congenital heart diseases to be performed in this field.

Inclusion Criteria:

Before corrective procedure for CHD, two of bellow ten criteria should be met:

• Decreased respiratory infection & decreased exercise tolerance
• Pulse SaO2 < 93% in left-right shunt CHD case (in room air)
• EKG: right ventricular hypertrophy, right atrial dilatation
• Chest X-ray: enhanced vascular signs in trans-hilar, loss of blood vessel in bilateral lung fields, pulmonary arterial trunk dilatation, right ventricular enlargement
• Cardiac echocardiography: fast tricuspid or pulmonary valve regurgitant velocity, ventricular and aortic level bidirectional shunt, or even right-to-left shunt
• Underfilling of pulmonary capillary, 'pruning' of the peripheral blood vessels
• Pp/Ps > 0.75
• Qp/Qs <1.5
• PVR > 9WU/m2
• Rp/Rs > 0.5

Exclusion Criteria:

• a body weight of < 2 kg,
• prematurity (birth 36 weeks postconceptual age)
• renal dysfunction (creatinine >= 1.5 mg/dL 48 hours before surgery)
• PLT < 50,000*109/L and obvious bleeding
• LCOS or hypotension on arrival to the intensive care unit

After corrective procedure for CHD:

• deficient anatomy associated with remained intracardiac shunts and severe artrio-ventricular regurgitation
• severe arrhythmia led to low cardiac output