This is a multi-center, perspective, and exploratory study aimed at evaluating the 3-years clinical outcome of Potts-shunt procedure for pediatric patients with severe pulmonary artery hypertension (PAH). The included criteria are as followed: 1)6 months < age ≤ 18 years; 2) ESC 2022 Group I PAH; 3) Have received standardized drug therapy for at least 6-9 months and still remain at intermediate to high/high-risk status of the criteria of ESC2022; 4) Presenting with significant clinical manifestations (i.e., progressive symptoms/syncope history/growth and development restriction, etc); 5) Informed consent form signed by the patient and their guardian. The excluded criteria are as followed: 1) ESC 2022 Group II-V PAH; 2) Poor right ventricular function: RVEF < 25% or RVFAC < 20%; 3) Deteriorated general condition: requiring ICU resuscitation or ECMO assistance; 4) Pulmonary artery pressure/main arterial pressure ratio < 0.7; 5) Six-minute walk distance < 150 meters (only applicable to patients aged 8 and above); 6) No significant improvement in RVEF under triple drug therapy. All of the pediatric patients with severe PAH who attend to pediatric cardiac outpatient clinic and meet the designed included criteria and excluded criteria will be enrolled in this study. All of the participants will be divided into two groups (Potts-shunt combined with conventional drug therapy group and only conventional drug therapy group) according to their individual health status (i.e., some contraindications of surgery) and their (or their parents') aspiration for Potts-shunts procedure. Follow-up is designed (eight-times follow-up) at the time of Potts-shunt procedure, post-operative ICU period, one month, three months, six months, one year, two years, and three years after Potts-shunt procedure or the rejection of Potts-shunt procedure. The items of follow-up include state of survival, whether or not have the lung transplantation (LTx), clinical manifestation, laboratory examination, function of right ventricle (detected by echocardiogram and cardiac magnetic resonance imaging), and the pulmonary circulation pressure (detected by right heart catheterization or Swan-Ganz catheterization). Primary outcome is the incidence rates of death or LTx three-years after Potts-shunt. Secondary outcomes are as followed: 1) Number and incidence rate of postoperative complications in patients undergoing Potts-shunt procedure; 2) Three-year WHO cardiac functional and 6-minute walk distance after Potts-shunt procedure; 3) the NT-ProBNP levels three-years after Potts-shunt procedure; 4) Right ventricular function on echocardiography three years after Potts-shunt procedure; 5) Right ventricular function on cardiac magnetic resonance imaging three years after Potts-shunt procedure; 6) Pulmonary circulation pressure measured by right heart catheterization or Swan-Ganz catheterization three years after Potts-shunt procedure; 7) Three-year mortality or LTx incidence rates after only conventional drug therapy.

Inclusion Criteria:

1. 6 months &lt; age ≤ 18 years;
2. ESC 2022 Group I PAH;
3. Have received standardized drug therapy for at least 6-9 months and still remain at intermediate to high/high-risk status of the criteria of ESC2022;
4. Presenting with significant clinical manifestations (i.e., progressive symptoms/syncope history/growth and development restriction, etc);
5. Informed consent form signed by the patient and their guardian.

Exclusion Criteria:

1. ESC 2022 Group II-V PAH;
2. Poor right ventricular function: RVEF &lt; 25% or RVFAC &lt; 20%;
3. Deteriorated general condition: requiring ICU resuscitation or ECMO assistance;
4. Pulmonary artery pressure/main arterial pressure ratio &lt; 0.7;
5. Six-minute walk distance &lt; 150 meters (only applicable to patients aged 8 and above);
6. No significant improvement in RVEF under triple drug therapy.