Under normal conditions, the pulmonary veins drain to the left atrium, whereas in complete pulmonary venous malformation, all pulmonary veins drain to the right atrium and then shunt to the left atrium through the foramen ovale or atrial septal defect. 1.Typing According to anatomical typing, complete pulmonary venous malformation drainage can be divided into supracardiac, intracardiac, subcardiac and mixed types. Supracardiac type is the pulmonary vein converging into the superior vena cava or the innominate vein through the vertical vein. The intracardiac type is where the pulmonary vein connects directly to the right atrium or coronary sinus. The subcardiac type is where the pulmonary vein connects to the vena cava via the vertical vein. The mixed type is any combination of the above three subtypes that converge into the right atrium via different routes. Complete pulmonary venous malformation drainage can be divided into obstructive complete pulmonary venous malformation drainage and non-obstructive complete pulmonary venous malformation drainage according to whether the pulmonary venous drainage pathway is obstructed or not. 2. Hazards Since all pulmonary veins drain to the right atrium, the survival of the patient depends on the right-to-left shunt at the atrial level, and the mixing of body and pulmonary venous blood can lead to varying degrees of cyanosis and severe respiratory distress in the child. Both pulmonary hemoptysis and pulmonary vein obstruction can lead to pulmonary hypertension in children. In children with complete pulmonary venous malformation drainage, the left heart is poorly developed and is prone to heart failure, such as shortness of breath, feeding difficulties and excessive sweating. 3.Surgical indication Complete pulmonary venous malformation drainage has no possibility of self-healing, so once the disease is diagnosed, there is an indication for surgery. 4.Surgery timing For obstructive complete pulmonary venous malformation drainage should be operated as early as possible, for serious children in order to save life, emergency surgery is needed. For non-obstructive complete pulmonary venous malformation drainage, it can be treated by elective surgery in early infancy. 5. Surgical risks (1) Low cardiac output syndrome: Since all children have poor left heart development and need to assume the normal left heart workload after surgery, all children have different degrees of low cardiac output syndrome. In order to reduce the workload of a single cardiac systole and to reduce the cardiac load, patients need to maintain a high heart rate, and intraoperative temporary pacemakers are routinely installed and removed before discharge. Individual children with severe low cardiac output may require ECMO assisted therapy. (2) Pulmonary hypertension crisis: Pulmonary hypertension may exist because the child has already developed preoperative pulmonary hypertension and the degree of pulmonary artery pressure drop varies in children after malformation correction. (3) Recent pulmonary vein obstruction: About 10% of children develop pulmonary vein obstruction after surgery and require surgical intervention. (4) Cardiac arrhythmia. This may be related to the high proportion of subcardiac and obstructive children in foreign patients. 7.Surgery cost Depending on the severity of the child’s condition, the hospital deposit for complete pulmonary venous malformation drainage at Fu Wai Hospital is around 80-100,000 RMB.