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Successful management of aortic coarctation in a 556 g extremely preterm infant

A male infant was born as the smaller twin through cesarean section because of twin-to-twin transfusion syndrome (TTTS) at 27 weeks and 4 days of gestation. His birthweight was 556 g and the larger twin was 980 g. After intubation for respiratory distress, initial routine echocardiography revealed patent ductus arteriosus with left-to-right shunt without ventricular septal defect (VSD). We then initiated prophylactic indomethacin (INDO) administration (0.1 mg/kg) for patent ductus closure. On day 2 of life, he became anuric with undetectable blood pressure (BP) and oxygen saturation in the lower extremities. Second echocardiography revealed significant isthmic coarctation of the aorta with a diameter of 1.2 mm (Fig. 1a) and peak gradient on Doppler study of 27 mmHg (Fig. 1b). At this point, the arterial duct was still patent and the shunt was bidirectional. Immediately after the initiation of prostaglandin E1 (PGE1) infusion, the BP of the lower extremities became pulsatile and anuria improved. Thereafter, PGE1 was controlled at levels of 6 to 12 ng/kg/h to maintain the ductal shunt. On day 10 of life, three-dimensional computed tomogram angiography confirmed a critical coarctation of the aorta (Fig. 1c). Our collaborative team, including the Departments of Pediatric Cardiology and Pediatric Cardiovascular Surgery and the parents reached a consensus that intensive medical therapy should be continued in the hope of further growth by considering the risk of surgical complications in such an extremely low birthweight (ELBW) infant. After education for physicians and nurses, a permissive hypercapnia strategy (target PaCO2 of 6080 mmHg) with mechanical ventilation and continuous sedation by fentanyl was applied strictly to increase pulmonary vascular resistance and maintain bidirectional or right-to-left shunting through the ductal shunt. Under the above conditions, he was able to tolerate enteral feeding. On day 28 of life, his bodyweight was increased to 990 g by enteral and parenteral nutrition but the inspiratory oxygen fraction (FiO2) gradually increased to 40–50%, with abnormal chest X-ray findings of a hazy shadow, consistent with developing bronchopulmonary dysplasia (BPD). Hydrocortisone therapy was transiently effective in reducing FiO2. Although SpO2 fluctuation due to the BPD development made ventilation using the hypercapnia strategy difficult, enteral feeding was well tolerated. After day 50 of life, bodyweight gain declined, accompanied by increased hepatic enzyme levels. On day 57 of life (35 weeks and 5 days postmenstrual age with a bodyweight of 1,286 g), our team selected surgical repair of the coarctation with end-to-end anastomosis of the aorta via cardiopulmonary bypass (CPB) and ligation of the patent ductus. The duration of CPB was 103 min and the aortic clamping time was 31 min. No significant complications were observed during the perioperative period. He was successfully extubated after 72 days of mechanical ventilation, but sildenafil was started for the treatment of pulmonary hypertension on day 81 of life. Continuous positive airway pressure was continued for 4 months. On day 156 of life, he was discharged with a bodyweight of 2,910 g. At the corrected age of 6 years, his weight reached 14.3 kg without cardiac symptoms or significant neurodevelopmental delay. There was no aortic stenosis across the coarctation site on echocardiography. Correspondence: Sota Iwatani, MD, PhD, Department of Neonatology, Hyogo Prefectural Kobe Children’s Hospital, 1-6-7 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan. Email: stiwatani_kch@hp.pref.hyogo.jp Received 26 February 2020; revised 6 April 2020; accepted 16 April 2020. doi: 10.1111/ped.14259