Two-stage endovascular balloon angioplasty and stent implantation for supravalvular pulmonary stenosis in a 33-month-old boy incurring congestive heart failure following arterial switch operation.

We report a 33-month-old boy, who had undergone arterial switch operation (ASO) for simple transposition of the great arteries (TGA) since birth, presenting with exercise intolerance with dyspnoea, tachypnoea, tachycardia, cardiomegaly and hepatomegaly. Doppler echocardiography showed severe tricuspid regurgitation and dilatation of the right atrium. At 28 months, cardiac catheterization tracked down the culprit to be right ventricular outflow tract obstruction (RVOTO) manifested at the mid-portion of the main pulmonary artery (MPA) as supravalvular pulmonary stenosis (SVPS) and measuring 2.98 mm in diameter. There was a pressure gradient of 76 mmHg between the right ventricle and the distal portion of the MPA. The lumen was initially dilated to 6.79 mm by balloon angioplasty (BA), after which the pressure gradient dropped to 51 mmHg. However, cardiomegaly and hepatomegaly lingered for 5 months. Stent implantation (SI) was performed at 33 months, after which the lumen was dilated to 9.99 mm and the pressure gradient dropped to 20 mmHg. Liver span decreased from 10 cm to 6 cm.There was a recrudescence of physical activity. Echocardiography showed regression of tricuspid regurgitation and dilatation of the right atrium at the 12-month follow-up.