The goal of this clinical trial is to evaluate the safety and potential efficacy of PNEUMOSTEM® for improving respiratory outcomes in very premature infants diagnosed with Early Pulmonary Arterial Hypertension. The main questions it aims to answer are:
* In very premature infants diagnosed with early pulmonary arterial hypertension, will a single intratracheal administration of PNEUMOSTEM®(Allogeneic umbilical cord blood-derived mesenchymal stem cells) result in improvement of pulmonary arterial hypertension based on echocardiographic assessment? * In very premature infants diagnosed with early pulmonary arterial hypertension who show improvement of pulmonary arterial hypertension based on echocardiographic assessment following a single intratracheal administration of PNEUMOSTEM®(Allogeneic umbilical cord blood-derived mesenchymal stem cells), at what time point does this improvement occur?
Participants will:
* Single intratracheal dose of PNEUMOSTEM® at 2.0 x 10,000,000 cells/kg * Acute adverse event monitoring: 24 hours post-administration for safety assessment * Follow- up time points: Day 1(Baseline, PNEUMOSTEM® administration), Day 2, Week 1, Week 2, Postnatal Day 28, PMA 36\~40 weeks
Premature infants within 2 weeks of birth with a gestational age of 28 weeks or less or birth weight of less than 1,250g who require continuous invasive mechanical ventilation
Sytemic or suprasystemic pulmonary artery pressure >40mmHg(based on peak Doppler velocity of tricuspid regurgitation)
Right-to-left or bidirectional shunt through patent ductus arteriosus, foramen ovale, or atrial septal defect
Flattened interventricular septum or D-shaped left ventricle at end systole ② When receiving nitric oxide(NO) inhalation therapy for persistent pulmonary hypertension of the newborn(PPHN) within 3 days after birth
Those witth cyanotic congenital heart defects or acyanotic congenital heart defects causing heart failure, excluding patent ductus arteriosus in premature infatns
Those with severe pulmonary malformations such as congenital diaphragmatic hernia or congenital cystic lung disease
Those who underwent surgery within 72 hours before or after administration of the investigational cell product, or those for whom surgery is anticipated
Those who received surfactant within 24 hours prior to administration of the investigattional cell product