Surgical Strategy According to Anatomy in ccTGA
#5 Conventional (Physiologic) Repair
When and why physiologic repair is chosen
In a subset of patients with ccTGA, the anatomy is not suitable for an anatomic repair (double switch or Senning–Rastelli). This is typical when:
- Pulmonary stenosis or atresia (PS/PA+) is present, so the native pulmonary valve and subpulmonary outflow cannot be used as a future neo-aortic valve, and
- The VSD is absent, small, or unfavourably positioned, preventing construction of a short, non-obstructive LV–aortic baffle.
Under these circumstances, forcing an anatomic correction risks residual LVOT obstruction, complex and tortuous tunnels, or prohibitive operative complexity. For such patients, the more reproducible option is a conventional (physiologic) repair, in which the morphologic right ventricle (RV) remains the systemic ventricle and surgery focuses on:
- Creating an adequate, non-obstructed pulmonary outflow pathway, and
- Treating associated lesions (VSD, PS/PA, systemic AV valve regurgitation), while preserving the native AV and VA connections.
Scenario 1: PS/PA(+) with a small or unfavourably aligned VSD
When a VSD is present but too small, restrictive, or remote to be used for Rastelli-type rerouting, it is managed as a conventional defect:
- The VSD is closed directly or with a patch, eliminating significant left-to-right shunt and protecting the pulmonary vasculature.
- Because the morphologic LV faces a stenotic pulmonary outflow, a left ventricle–pulmonary artery (LV–PA) conduit is constructed to bypass the obstructed LV–PA pathway.
Functionally:
- The LV remains the subpulmonary ventricle, ejecting through the LV–PA conduit.
- The morphologic RV continues to support the systemic circulation, ejecting into the aorta as before.
This approach relieves cyanosis and RV pressure overload due to PS/PA while maintaining the physiologic sequence RA→LV→PA and LA→RV→Ao.
Scenario 2: PS/PA(+) with an intact ventricular septum
In ccTGA with PS/PA and no VSD, there is no intracardiac communication that can be exploited to connect the LV to the aorta. Surgical goals are therefore limited to re-establishing unobstructed pulmonary blood flow:
- A LV–PA conduit (or, in selected anatomies, a conduit from the subpulmonary ventricle) is placed to bypass the obstructed native pulmonary valve or subpulmonary outflow.
- The ventricular septum is left intact; no systemic–pulmonary shunt is created or closed.
- The systemic circulation remains supported by the morphologic RV, and the LV continues in the subpulmonary role.
Additional components of physiologic repair
Regardless of VSD status, conventional repair in ccTGA frequently incorporates:
- Relief of additional outflow lesions, such as valvar or subvalvar PS.
- Systemic AV (tricuspid) valve repair or replacement when significant regurgitation is present, recognizing that this valve remains on the systemic side and is a major determinant of long-term outcome.
- Permanent pacemaker implantation when pre-existing or procedure-related conduction disease is present, reflecting the inherently abnormal conduction system in ccTGA.
The overall objective is to normalize pressures and flows across both circuits as much as possible, accepting that the morphologic RV and tricuspid valve will remain exposed to systemic afterload.
Evidence on long-term outcomes
Long-term series of physiologic repair demonstrate that this strategy can provide good early and intermediate results, with relief of cyanosis and improvement in functional class. However, they also highlight the progressive vulnerability of the systemic RV and tricuspid valve:
- In a cohort undergoing physiologic repair (including conventional Rastelli-type operations), 20-year survival was approximately 72%, but only about 44% of patients remained free from significant systemic tricuspid regurgitation, and reoperation—often for conduit or valve issues—was common.[1]
- A large multicenter study of 240 patients with ccTGA showed that pathways leaving the morphologic RV as the systemic ventricle were associated with higher rates of systemic RV dysfunction and tricuspid regurgitation compared with anatomic repair pathways, despite acceptable survival in the intermediate term.[2]
- A systematic review and meta-analysis directly comparing anatomic versus physiologic repair found that anatomic repair was associated with lower post-discharge mortality (≈6% vs 10%) and substantially less systemic ventricular dysfunction on follow-up, reinforcing the long-term limitations of physiologic strategies.[3]
- Beyond the pediatric era, data on adults with a systemic RV (after either atrial switch or ccTGA) show high cumulative incidences of heart failure, arrhythmia, and significant TR, underscoring the chronic load mismatch when a morphologic RV supports the systemic circulation.[4]
Taken together, these data support the use of physiologic repair as a necessary compromise when anatomy precludes anatomic correction, while emphasizing the need for meticulous follow-up and timely reintervention.
Expected course and long-term considerations
After conventional repair:
- Pulmonary blood flow is restored, and symptoms related to PS/PA or large VSD are usually relieved.
- Many patients enjoy good functional status (NYHA I–II) for years.
However, the fundamental limitation persists: the systemic ventricle is a morphologic RV with a systemic tricuspid valve. Over time, this predisposes to:
- Progressive systemic RV dilation and systolic dysfunction
- Worsening systemic tricuspid regurgitation, and
- Arrhythmias and heart block, either intrinsic to ccTGA or related to previous surgery.
Consequently, patients managed with physiologic repair require lifelong surveillance, including:
- Serial imaging (echo, and often MRI) of systemic RV size and function;
- Assessment of systemic tricuspid valve regurgitation;
- Evaluation of conduit integrity (stenosis, regurgitation, or calcification); and
- Ongoing rhythm monitoring and pacemaker management.
In selected patients who develop progressive systemic RV failure despite optimal medical and surgical therapy, options such as late conversion to an anatomic repair, cardiac resynchronization therapy, or ultimately heart transplantation may be considered on an individual basis.[4]
Summary
Conventional (physiologic) repair in ccTGA is chosen when pulmonary stenosis or atresia is present and the VSD anatomy does not allow safe LV–aortic rerouting. In these anatomies, ASO is not feasible and Senning–Rastelli is not possible, so surgery focuses on:
- Bypassing the obstructed pulmonary outflow—typically with an LV–PA conduit, and
- Correcting associated lesions while leaving the morphologic RV in the systemic position.
This strategy provides reliable symptom relief and satisfactory early outcomes, but it accepts the long-term risks inherent to a systemic right ventricle and systemic tricuspid valve, making careful longitudinal follow-up and timely reintervention essential.
References
[1] Adachi O, Kawashima Y, Yamagishi M, et al. Long-term results after physiologic repair for congenitally corrected transposition of the great arteries. Gen Thorac Cardiovasc Surg. 2016;64(12):715-721.
[2] Barrios PA, Belli E, Agarwal A, et al. Outcomes of treatment pathways in 240 patients with congenitally corrected transposition of the great arteries. J Thorac Cardiovasc Surg. 2021;161(4):1463-1473.e7.
[3] Anzai I, Tutarel O, Brida M, et al. Outcomes After Anatomic Versus Physiologic Repair of Congenitally Corrected Transposition of the Great Arteries: A Systematic Review and Meta-Analysis. World J Pediatr Congenit Heart Surg. 2023;14(1):70-76.
[4] Ansari Ramandi MM, Clerkin KJ, Schoenike MW, et al. Long-term outcome of patients with transposition of the great arteries and a systemic right ventricle: A meta-analysis. Int J Cardiol. 2023;383:90-96.