Half-Turned Truncal Switch Operation for Dextro-Transposition of Great Arteries

The half-turned truncal switch operation was introduced by Professor Masaaki Yamagishi in 2003 for children with complex transposition of great arteries and double outlet right ventricle (TGA type), with remote or small ventricular septal defect and mild to moderate left ventricular outflow tract obstruction (1,2). It is a complex cardiac surgical procedure, but it can be carried out with good success. It provides good hemodynamics and better growth potential in children with complex TGA.

The advantage of the half-turned truncal switch operation is the possibility of biventricular repair in remote or small ventricular septal defect (VSD) in complex transposition of great arteries (TGA), creation of hemodynamically normal left ventricular outflow tract, preservation of growth potential in the right ventricular outflow tract, and avoidance of the right ventricle to pulmonary artery (RV-PA) conduit.

This video shows a similar operative technique for a five-year-old female child with dextro-transposition (D-TGA) of great arteries, large muscular VSD, and severe valvular and subvalvular pulmonary stenosis.

Clinical History

A five-year-old girl was evaluated for failure to thrive, cyanosis, and class III dyspnea on exertion. Her room air saturation was 82%. There was grade 3/6 ejection systolic murmur in the pulmonary area. A transthoracic 2D echo confirmed the diagnosis of D-TGA, large outlet muscular ventricular septal defect, and severe valvular and subvalvular pulmonary stenosis. Both great arteries were antero-posteriorly related. The patient’s pulmonary annulus to aortic annulus diameter ratio was 0.7. The surgeons proceeded with a half-turned truncal switch operation with monocuspid transannular patch right ventricular outflow tract reconstruction.

Operative Technique

First, cardiopulmonary bypass was established with aortic, high superior vena cava (SVC), and inferior vena cava (IVC) cannulation. The aorta was cross-clamped and the heart was arrested with del Nido cardioplegia solution. Next, the ascending aorta was transected about 5 mm above the sinotubular junction. The main pulmonary artery was transacted just before the bifurcation. Left and right coronary arteries were harvested from the corresponding sinuses, and both were well-mobilized. The truncal root incision was then marked all around using a marking pen. 

Next, the aortic root was harvested by making an incision on the anterior wall of the right ventricle about 8 mm from the aortic valve. The incision was extended on either side of aortic root, staying away from the aortic valve cusps and both coronary arteries up to the infundibular septum. The incision was then extended along the posterior aspect of the pulmonary root without damaging the pulmonary mitral curtain. Both root incisions were joined by cutting the infundibular septum. The entire truncal root was then removed and turned to 180 degrees. 

The routability of VSD was confirmed and the size of the VSD was measured for tailoring the pericardial patch. The width of the superior margin of the pericardial patch was adjusted to the required length for aortic annular augmentation. Then, the VSD was closed with a 0.6% glutaraldehyde treated autologous pericardial patch using 6-0 Prolene. The superior aspect of the patch was left unsutured. The aortic root was then sutured to the left ventricular outflow tract with eight interrupted 5-0 Prolene sutures, and all were seated and tied with pericardial pledget on either side. The superior aspect of the VSD patch was sutured to the aortic annulus. 

To avoid left coronary artery kinking, the defect in the aortic sinus was sutured with a small piece of crescent shaped pericardium, and the left main coronary was reimplanted into the pericardial augmented aortic sinus. The right coronary was reimplanted into the corresponding aortic sinus directly. Then, the LeCompte maneuver was performed. The aortic root was anastomosed to the ascending aorta using 6-0 Prolene. The right ventricular outflow tract was reconstructed with a treated pericardial patch using 5-0 Prolene. The cross-clamp was released, and the patient’s heart picked up in sinus rhythm. 

Next, the pulmonary valve commissurotomy was performed, but it was not admitting more than a size fourteen Hegar dilator (z score 1.4-1.7). Hence, it was decided to cut across the pulmonary valve annulus along the anterior commissure. All the pulmonary valve leaflets were preserved. The posterior continuity between the pulmonary root and distal main pulmonary artery (MPA) was established using 6-0 Prolene. Then, a large bovine pericardial patch was used anteriorly, extending from the right ventricular outflow tract (RVOT) into the proximal MPA across the annulus. The monocuspid pulmonary valve was created inside using 0.1 mm polytetrafluorethylene (PTFE) membrane.

References

1. Masaaki Yamagishi. Half turned truncal switch operation for transposition of great arteries with left ventricular outflow tract obstruction. Operative Techniques in Thoracic and Cardiovasculary Surgery. 2021 – August 25
2. Yamagishi M, Shuntoh K, Matsushita Tet al. Half-turned truncal switch operation for complete transposition of the great arteries with ventricular septal defect and pulmonary stenosis. J Thorac Cardiovasc Surg. 2003; 125: 966-968

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