Ventricular Septation and Fontan Procedures for the Univentricular Heart

Summary

Indications and results were compared between transatrial ventricular septation (S) and Fontan (F) procedures for univentricular heart (UVH). Of 21 patients who had ventricular septation, 19 had a UVH of the left ventricular (LV) type. Twenty patients had two atrioventricular (AV) valves, and 1 had a common AV valve. Fifteen patients had previous pulmonary artery banding (PAB), and subaortic steno-sis (SAS) mainly caused by a narrow outlet foramen required enlargement in 9. The smallest ventricular volume was 172% of normal. Of 92 patients who had the Fontan procedure, 31 were of the LV type and the remaining 61 of the right ventricular (RV) type. Forty-nine patients had one or more systemic-to-pulmonary artery (SP) shunts for pulmonary stenosis (PS), and 7 had PAB previously. AV valve regurgitation was repaired simultaneously in 37 cases. The preoperative mean pulmonary artery (PA) pressure (29 ± 15 vs 15 ± 4 mmHg) and pulmonary vascular resistance (Rp, 3.2 ± 2.3 vs 1.7 ± 0.8 Wood units) were significantly higher in the septation group than in the Fontan group. There was no significant difference in postoperative cardiac index (S, 3.1 ± 1.2; F, 2.8 ± 0.7), and operative mortality and long-term survival (S, 89.5% vs F, 88.6% at 8 years) of the two groups were comparable. Risk factors for death after the procedures were high LV systolic and end-diastolic pressures and ventricular hypertrophy for the septation, and high Rp, low PaO₂, pulmonary venous anomaly, and longer aortic cross-clamp time for the Fontan procedure. In conclusion, patients with UVH of LV type without significant PS and AV valve atresia or stenosis can be good candidates for ventricular septation. After PAB as a palliative procedure, an early septation procedure is recommended because reduction in ventricular volume and concentric hypertrophy caused by progression of SAS may ensue. Patients with UVH of RV type and of LV type can be candidates for Fontan procedure, and should undergo early and often repeated palliative procedures that prevent pulmonary hypertensive changes (tight PAB in patients without PS) and that promote development of the pulmonary vascular bed (adequate SP shunt for PS or after initial PAB).