Commentary: What switch, to switch or not to switch: That is the question!

Hamlet's dilemma.

Central Message.

In patients presenting late with D-transposition of the great arteries and total anomalous pulmonary venous return, a modified Senning procedure provides excellent physiological correction.

See Article page 223.

As predicted by pioneering surgeon Ake Senning in his response to an editorial lauding the success of his physiological correction of D-transposition of the great arteries (D-TGA), the anatomic arterial switch operation is now the gold standard for the surgical correction of D-TGA and the atrial inversion operation is performed infrequently.¹ However, atrial inversion procedures are currently experiencing a renaissance in children with congenitally corrected transposition (C-CTGA) as part of a double-switch operation and in children with D-TGA who present late.²

The early technically complex Senning operation³ made way for the technically less demanding Mustard operation using a large prosthetic patch.⁴ However, an increased incidence of baffle obstruction, leaks, and inferior late outcomes in smaller children related to the larger amount of prosthetic material and therefore less growth potential with the Mustard procedure resulted in the pendulum swinging back toward the Senning procedure.⁵ Over time, modifications to the original atrial inversion operation with the Shumaker in situ pericardial well⁶ and hemi-Mustard one-and-a-half ventricle repair⁷ allowed for wider application of the atrial switch, particularly in patients with difficult anatomy, such as dextrocardia, situs inversus, and small right ventricular volume.

A small subset of patients who have undergone an atrial switch operation may present with right ventricular dysfunction. For these patients, left ventricular retraining by way of pulmonary artery banding followed by a late arterial switch has been suggested as an alternative to heart transplantation.⁸

In this issue of the Journal, Mishra and colleagues⁹ describe the successful use of the Shumaker modification of the Senning procedure with concomitant repair of total anomalous venous return (TAPVR) in 3 patients with D-TGA and TAPVR that presented late. Important technical points (some of which are better appreciated in the accompanying video) included are that atrial septal flap advancement to divert pulmonary venous return is not required with TAPVR. Furthermore, only the rightward aspect (leftward in cases of situs inversus) of the pulmonary venous confluence should be dissected and opened with excision of the anterior wall. The in-situ pericardial well provides a larger surface area to account for unusual anatomic variants where the atrial free wall surface area is often lacking and may compromise the systemic and pulmonary venous baffles. The extensive unroofing of the coronary sinus that the authors describe is an important step that avoids the creation of a ridge with potential obstruction of the inferior vena cava end of the systemic venous baffle. Unroofing also allows diversion of coronary sinus return to the systemic venous circulation, which is useful when a left superior vena cava is present, allows more space to suture away from the atrioventricular node in the triangle of Koch (less relevant in C-CTGA), and permits future coronary sinus lead placement.

The authors' experience highlights the significance of revisiting the technical pearls, pitfalls, and lessons learned with the atrial inversion techniques, which although performed infrequently today, remain an important part of the congenital heart surgeon's armamentarium.