D-Transposition s/p Arterial Switch Operation

Abstract

In d-transposition of the great arteries (d-TGA), the great vessels arise from the wrong side of the ventricular septum; i.e., the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. When an arterial switch operation (ASO) is performed, the great vessels are transected above the sinuses and re-anastomosed to the hemodynamically and anatomically appropriate arterial roots. The coronary arteries are also transferred, along with a “button” of aortic tissue, from the original aortic root to the neoaortic root. Patients who have had successful ASO generally have excellent exercise function. Pulmonary artery stenosis resulting from stretching and/or kinking of the pulmonary arteries during surgery can cause pulmonary blood flow maldistribution and ventilation/perfusion mismatch, which may manifest during an exercise test as elevation of the V̇E/V̇CO2 slope. Coronary artery obstructions associated with the transfer of the coronary arteries during the surgery are also sometimes encountered. Exercise testing may be of value in this context, but it must be recognized that the sensitivity and specificity of exercise testing for these lesions are imperfect.