Case report

A female infant, without a previous diagnosis of CHD, was born at 28 6/7 weeks of gestation via Caesarean section for preterm labour with a birth weight of 1585 g. She required continuous positive airway pressure for ~30 minutes following birth but was subsequently weaned to room air. She did well for the first 2 days of life, not requiring respiratory or cardiovascular support and advancing on feeds. On day of life 3, her lower extremities were noted to be mottled. Upper- and lower-extremity blood pressures were measured using a cuff and showed a gradient of 50 mmHg. Echocardiography was performed and the echocardiogram showed an atrial septal defect, ventricular septal defect, concern for aortic coarctation, and severely depressed left ventricular systolic function. She was started on prostaglandin E1 and dopamine, intubated, and transferred to our facility. Upon arrival, echocardiography was performed and the echocardiogram showed a type-B interrupted aortic arch with a large posterior malalignment ventricular septal defect, large atrial septal defect, moderate-to-large ductus that was slightly narrowed at the pulmonary artery end, and an apparent membrane restricting flow at the aortic end (Fig 1). There was a mean gradient of 20 mmHg across the ductus arteriosus, and the abdominal aortic flow pattern on spectral Doppler was dampened, consistent with ductal obstruction. The aortic valve was bicuspid and moderately hypoplastic (annulus Z-score −3.3), and the left ventricular systolic function was moderately-to-severely depressed. Given the restriction of flow through the ductus arteriosus at the aortic end, which was unresponsive to prostaglandin E1, the decision was made to proceed with emergent intervention. She was deemed a high-risk candidate for cardiopulmonary bypass, given her prematurity, low birth weight, and ventricular dysfunction; therefore, the decision was made to perform an urgent hybrid stage-I procedure.

Figure 1

Two-dimensional and color doppler showing ductus arteriosus obstruction and flow acceleration at the level of obstruction.

Figure 2

Angiogram showing the ductus arteriosus prior to intervention (a) and following stent implantation (b).

She was taken to the hybrid cardiac catheterisation laboratory. A hybrid stage-I palliation was performed using our standard institutional approach, with placement of bilateral pulmonary artery bands and ductus arteriosus stent.Reference Zampi, Hirsch, Goldstein and Armstrong ⁵ The pulmonary artery bands were adjusted until the mean pressures were 14 mmHg in the left pulmonary artery and 17 mmHg in the right. The anatomy of the ductus arteriosus is shown in Figure 2a. The ductus arteriosus measured 3.4 mm at the most narrow portion and the more proximal ductus arteriosus measured 5.7 mm. Because of the stenotic ductus arteriosus, a 16 mm long Formula 418 stent pre-mounted on a 6 mm balloon (Cook Medical, Bloomington, Indiana, United States of America) was chosen. Figure 2b shows the stented ductus arteriosus. Following the procedure, the patient was brought to the paediatric cardiac !after admission, the infant was confirmed to have DiGeorge syndrome. By day of life 7 – that is, at 4 days following her hybrid procedure – she had normal biventricular systolic function. Over the next several months, she did not require further intervention. There was no obstruction across the ductus arteriosus stent on echocardiography. She underwent complete surgical repair at 3 months of age at a weight of 3.8 kg. This repair included an end-to-end aortic anastomosis with pulmonary allograft patch augmentation of the aorta, ligation and division of the left subclavian artery, ventricular septal defect closure, atrial septal defect closure, bilateral branch pulmonary artery band removal, and ligation and division of the ductus arteriosus with removal of the stent. Her postoperative course was complicated by several failed extubation attempts. She subsequently required left hemi-diaphragm plication and was then weaned from all respiratory support. She was discharged home ~3 months after definitive repair.