Unknown Complication of Arterial Switch Operation

Abstract

A 17-year-old man with complete transposition of the great arteries who had undergone the arterial switch procedure was referred to our tertiary center to investigate systemic hypertension. High blood pressure (BP) was first documented at age 13 years and was controlled until age 16 years by enalapril (20 mg/d) and atenolol (100 mg/d). BP became uncontrolled despite the addition of 2 other antihypertensive drugs (amlodipine 10 mg/d and furosemide 20 mg/d). At admission, hypertension was still observed despite treatment. Left arm BP was 141/64 mm Hg, right arm BP was 149/63 mm Hg, left inferior limb BP was 153/58 mm Hg, and right inferior limb BP was 155/60 mm Hg. Twenty-four-hour ambulatory BP monitoring confirmed hypertension, with mean daytime BP at 159/78 mm Hg. Initial laboratory investigations, including measures of serum potassium and creatinine, quantitative proteinuria, renin, aldosterone, corticosteroids, and catecholamines in plasma and urine, were normal. Renal and adrenal ultrasound scans were also normal. Echocardiography showed moderate left ventricular (LV) hypertrophy. The aortic root was dilated, and aortic regurgitation was graded as mild (Table). An instantaneous gradient of 36 mm Hg was measured with a continuous-wave sample through the aortic isthmus. Cardiovascular magnetic resonance angiography performed with a 1.5-Telsa magnet showed a common origin of the left and right carotid arteries from the brachiocephalic artery, as well as a visible narrowing of the descending aorta (minimum diameter 14 mm) insufficient to define coarctation. A major finding was that the aortic arch had a Gothic …