Complete Atrioventricular Canal and Tetralogy of Fallot: Surgical Considerations

Abstract

A review of 13 autopsy specimens and of 13 patients who were operated on for complete atrioventricular (AV) canal and tetralogy of Fallot between 1975 and 1985 revealed a number of anatomical details that are important in the successful repair of this combined lesion. A bridging anterior leaflet was present in 25 hearts. A septum primum was present and attached to leaflet tissue in 13. In all 26, a ventricular septal communication was present beneath the bridging anterior leaflet and extended anteriorly, but in 14 there was no ventricular septal defect underneath the posterior leaflet. Additional pathological features included the following: leaflet tissue deficiency (4 hearts), single left papillary muscle (3), accessory valve orifice (4), and left ventricular (4) or right ventricular (RV) (1) dominance. All 26 had infundibular stenosis, and 10 had hypoplastic pulmonary annuli. One had pulmonary atresia, and 6 had branch pulmonary artery stenosis. Surgical technique was modified to include incision of the septum primum in 7. Because of rightward displacement of the anterior ventricular septum and also to minimize the risk of causing subaortic stenosis, the bridging anterior leaflet was divided more toward the tricuspid orifice so as to parallel the crest of the ventricular septum. Transannular RV outflow patches were used in 10 patients, and a right ventricle–pulmonary artery conduit was placed in 1 patient. Three required repair of branch pulmonary artery stenosis. There were no hospital deaths. Three patients died late of residual AV valve regurgitation and branch pulmonary artery stenosis (2) and sepsis (1). One patient with RV hypoplasia and postoperative tricuspid regurgitation had a Fontan operation. Four patients required left AV valve replacement (3 early and 1 late). The AV canal component in complete AV canal with tetralogy of Fallot is more complex than in isolated complete AV canal. Also, in addition to infundibular stenosis, other right-sided obstructions are common. A better understanding of the many anatomical variables has led to improvement in surgical results.