Corrected TGA-VSD: The Double Switch Procedure

Abstract

Congenitally Corrected Transposition of the Great Arteries (ccTGA) is a rare, complex condition that is characterised by atrio-ventricular and ventriculo-arterial discordance. There are a great variety of associated defects, of which VSD is commonest. The VSD is usually perimembranous but is variable in size. Patients with large VSD may require early pulmonary artery (PA) banding to prevent congestive cardiac failure.

Management is not straightforward since the associated defects and morphological sub-types produce a variety of symptoms that present at varying ages. This is complicated by the unpredictable performance of the morphological right ventricle and tricuspid valve in the systemic circulation. If surgery is required; then the aim for most procedures is to repair any associated lesions and restore the morphological left ventricle to the systemic circulation. This is achieved with the so-called ‘Double Switch’ procedure that combines atrial inversion (the Senning or Mustard procedure) with an arterial switch. This is also referred to as ‘anatomical repair’ to differentiate it from procedures that only address the associated lesions and leave the morphologic right ventricle in the systemic circulation (‘physiological repair’).

Patients with restrictive VSDs may require preparatory PA banding to retrain the morphological LV to sustain the systemic circulation.

The double-switch procedures pose specific technical challenges which are discussed in detail, together with management strategies and related surgical options such as the ‘one-and-a-half’ type repair.