Double Switch Operation
Double Switch Operation or the atrial switch-arterial switch operation is an anatomic repair performed for ccTGA when there is no valvular PS and a VSD is associated.
Some facts about Double Switch Operation:
- RV is allowed to pump deoxygenated blood to the lungs and the LV to pump oxygenated blood to the body in the double-switch procedure.
- Double switch operations provide anatomic repair in cases with congenitally cTGA.
- Morphological left ventricular (MLV) is converted into systemic ventricle and MRV into pulmonic ventricle.
- Atrial switch - Arterial switch Anatomic repair can be done by closing the VSD and applying an atrial switch and an arterial switch in congenital cTGA patients with VSD who have normal pulmonary valve and pulmonary outflow tract.
- Atrial switch can be done by either the Senning or Mustard procedure.
- Senning procedure is easier in terms of intracardiac geometry and architecture, and superior in terms of obstruction of venous return and the incidence of arrhythmia
- Interatrial re-septation and roofing of pulmonary venous atrium with autologous pericardial patch repair is usually performed.
- The opening to the AV (tricuspid) valve should be at least as large as the tricuspid valve diameter while creating the systemic venous neo-atrium, during direction of the superior vena cava (SVC) and inferior vena cava (IVC) to the MRV (pulmonic ventricle)
- The limbus fossa ovalis is resected at the entrance to the SVC and a 'cut-back' to the coronary sinus leaving it into the systemic venous atrium to achieve this.
Procedure for Double Switch Operation:
- The double-switch procedure is made of three basic steps including VSD closure, Atrial switch procedure and Arterial switch procedure.
- VSD in the subpulmonary area will be closed first either through the mitral valve, a right ventriculotomy, the right atrium, or the transaortic approach.
- The atrial septum is completely excised by creating a new common atrium which is done by the resection of the ovalis fossa. Special care should be taken to avoid any injury to the conduction system
- A portion of the septum secundum will be removed by some surgeon in order to facilitate the creation of the superior portion of the pericardial baffle.
- A baffle will be created so that the systemic venous flow is redirected to the tricuspid valve, and the pulmonary venous return is redirected to the mitral valve
- One edge of the baffle will be sutured over the opening of the four pulmonary veins and continues with superior and inferior vena cava, where as the final edge is secured to the anterior end of the atrial septum.
- Senning utilized autologous atrial tissue for all the steps of the venous reconstruction in the classic atrial switch operation
- Mustard proposed his modification of autologous pericardium in situations where the autologous tissue is not sufficient to provide unobstructed venous baffles
- The autologous pericardium is harvested as free patches and then used to create the baffle in his modification.
