Surgical ventricular septal defect repair: How large is too large?

Introduction

Ventricular septal defects (VSDs) vary widely in anatomy and size. Surgical treatment of very large VSDs can be challenging as no clear recommendations exist about which of these defects can undergo biventricular repair with septation and which should instead be palliated. While Fontan circulation is known to be associated with long-term morbidity, information is limited about how ventricular septation of large VSDs affects cardiac function.

Method

In this descriptive case series, we are presenting three cases in which patients initially deemed candidates for univentricular palliation due to very large VSDs but were ultimately chosen for septation at our institution. The aim was to share our experiences with these complex cases and demonstrate our lessons learned.

Results

All patients had a prior pulmonary artery band as the first stage of univentricular palliation. At the time of VSD septation, the median age was 2.5 years [2–2.5], with a median weight of 11 kg [8.4–12]. All cases presented a large perimembranous inlet-outlet VSD without AV septal malalignment. The median size of the VSDs in our series was 27 × 22 mm and 13.7 × 11.2 mm/m². A fibrous continuity between the tricuspid and the mitral valve with two separate AV junctions were described. No straddling was present and RV/LV ratio was comprised between 0.725 and 0.97 (Figure 1). Right heart catheterization showed normal pulmonary pressures. After multidisciplinary discussion, ventricular septation was concluded based on the two adequately sized separate AV valves without straddling, the RV/LV ratio, and the VSD which was considered technically feasible for a closure with muscular and fibrous borders. Because of the large VSD-patch, a staged approach was concluded with the pulmonary artery band being removed without enlarging the previously banded area allowing elevated RV pressures of > 50–60% of the systemic level, to promote positive ventricular–ventricular interactions. Median LVEF was 65% [62–67] at discharge. No heart block was observed.

Conclusion

Ventricular septation of three patients with large VSDs ≤ 15 mm/m² was successfull with good short-outcomes. A staged approach maintaining elevated right ventricular pressures helps to preserve positive ventricular interactions. Postponing surgical treatment to a later point after infancy seems to be a reasonable approach and allows for biventricular consideration.