Balloon Angioplasty for Ductus Arteriosus in Infant With Ductal Origin of the Left Pulmonary Artery Combination With Nitrogen Inhalation Therapy

Abstract

solated pulmonary artery is occasionally seen in children with tetralogy of Fallot, pulmonary atresia with ventricular septal defect, heterotaxia syndromes, and truncus arteriosus. In such cases, stenosis or occlusion of the proximal portion of the isolated pulmonary artery frequently occurs because of constriction by the ductal tissue, so management of the stenosis is a critical concern.Clinical experience of catheter intervention for the ductus arteriosus (DA) remain limited 1-5 and the indications are controversial. Both balloon angioplasty (BA) and stent implantation can potentially result in re-stenosis or complete occlusion. 3,6 Furthermore, stent implantation could interfere with any subsequent surgery. We report our experience using a combination of BA for the stenotic DA and nitrogen inhalation therapy in an infant with complex congenital heart disease with non-confluent unbalanced pulmonary blood flow. Case ReportA 2-day-old baby was referred because of heart murmur and cyanosis. He was diagnosed as having truncus arteriosus (Van Praagh type A3; ductal origin of the left pulmonary artery (LPA)). Color Doppler echocardiography showed trace blood flow in the DA. High-dose prostaglandin E1-CD was intravenously administered to open the DA, butCirculation Journal Vol.71, March 2007 was not effective. At the age of 8 days, catheter examination and angiography were performed after his parents gave written informed consent.The infant was heparinized during the procedure (150 IU/kg). Aortography revealed an extremely narrow DA, which connected to the LPA, and the distal pulmonary artery tree could not be demonstrated (Fig 1a). To salvage the LPA, a J-type guide wire (0.035 Radifocus, Terumo, Japan) was advanced with slight resistance through a 4Fr Judkins left-type catheter and the stenosis was dilated using a balloon catheter (4×20 mm, Power Flex P3, Cordis Corp, FL, USA) at 6 atm. The balloon size was 150% of the reference diameter of the distal LPA. The minimal lumen diameter (MLD) significantly increased from 0.7 mm to 2.7 mm after the procedure (Fig 1b). Oxygen saturation in the systemic artery slightly increased from 90% to 92% on room air and the left-to-right pulmonary perfusion ratio on the pulmonary perfusion scan significantly increased from 0.03 to 0.15. During the follow-up, the cardiothoracic ratio (CTR) on chest X-ray increased from 0.59 to 0.63 and tachypnea of 50 /min developed gradually with physiological dropping of pulmonary arterial resistance and increased pulmonary blood flow. Therefore, nitrogen gas was administered through a nasal positive airway pressure inhalation system at approximately 0.18 of the inspiratory oxygen fraction. Immediately after initiation of hypoxic therapy, the arterial systolic pressure dramatically increased from 46 mmHg to 68 mmHg and urination also increased. Three weeks after the procedure, echocardiography revealed diminished left pulmonary blood flow again, so at the age of 33 days, repeat BA was performed as before. The MLD increased from 1.8 mm to 2.7 mm...