Case Report
A 26-year-old female was diagnosed at 22 weeks gestational age (GA) with possible fetal congenital high airway obstruction syndrome (CHAOS).  Fetal MRI at 25 weeks GA revealed overexpansion of the right lung and suggested obstruction of the right mainstem bronchus (MSB) and ascites with polyhydramnios (Figure 1A). Fetal echocardiogram was normal. Fetal MRI at 33 weeks GA found decompression of the lung and resolution of hydrops (Figure 1B).
Due to fetal distress at 36+1 weeks GA, a cesarean section was performed. The male infant (1940 grams)had APGAR scores of 7/7 and required intubation on placental support. He demonstrated asymmetric chest wall movement and had absent breath sounds on the right. Chest x-ray showed complete opacification of the right lung (shown in Figure 2A). Echocardiogram revealed suprasystemic right ventricular pressure (RVP) with normal biventricular function. The infant was stabilized with inhaled epoprostenol, inhaled nitric oxide, intravenous epinephrine and intravenous phenylephrine.
At day of life 13, bronchoscopy confirmed complete stenosis of the right MSB just distal to the carina with normal anatomy otherwise including the left MSB (Figure 3A and 3B). Following regression of the ductus arteriosus, the infant had a long-segment left pulmonary artery (LPA) stenosis. Angiographically, the distal left lung vasculature appeared normal but the right side appeared dilated and tortuous. After angioplasty, the proximal LPA peak gradient improved (37 mmHg to 23 mmHg). Inotropic support was weaned off in days and the inhaled pulmonary vasodilatory agents were transitioned to enteral sildenafil.
MRI of the chest (Figure 1C) at 19 days of life revealed a normal bronchial branching pattern distal to the bronchial atresia and a substantial amount of right lung with normal appearing vasculature. Phase contrast illustrated a flow differential of 10% and 90% effective flow to the right and left lung, respectively.
The infant was extubated to non-invasive ventilatory support at 22 days of life (Figure 2B). Serial echocardiography illustrated worsening RVP due to LPA stenosis from progressive rightward mediastinal shift. Although the infant appeared clinically stable, his condition was thought to be tenuous and operative intervention was pursued. At 32 days of life (2,410 grams) the infant underwent a right slide tracheobronchoplasty on Extracorporeal Membrane Oxygenation (ECMO) support.
Through a median sternotomy and wide opening of the pleural spaces and pericardium in the midline,suspension of the rightward pericardium allowed direct right atrial and aortic cannulation. A 5 mm fibrous stalk was present connecting a short stub of the proximal MSB with the more distal MSB. This was transected distally and mucus was cleared from the right lung. Proximally, a wedge was removed from the trachea at the stump of the right MSB, and the incision carried superiorly creating a V shape opening. Ensuring similar circumferences, the distal MSB was then sutured to the trachea using a double armed 6-0 PDS, posteriorly to anteriorly. A leak test was performed and a fibrin sealant was applied around the anastomosis.
Postoperative chest x-ray showed right lung expansion (Figure 2C). On postoperative echocardiogram the infant had mild LPA stenosis with a peak gradient of ~24 mmHg and normalization of RVP estimates. Sildenafil was discontinued. He was extubated on post-operative day five to continuous positive airway pressure (CPAP). Late post-operative bronchoscopic evaluation was performed 2 months post slide tracheobronchoplasty, and showed a well healed widely patent anastomosis (Figure 4). At the time of this report, the infant is discharged without respiratory support and thriving at six months of age.