Subaortic obstruction in hearts with a univentricular connection to a dominant left ventricle and an anterior subaortic outlet chamber. Results of a staged approach.

In 1984 we reported a 56% mortality after major cardiac operations for patients with univentricular connection to a dominant left ventricle, an anterior subaortic outlet chamber, and subaortic obstruction. Since then we have adopted a staged approach to this repair. Between 1984 and 1989 32 patients had such operations. The overall mortality has decreased (16%; p < 0.001). The current cohort was divided by subaortic gradient into three subgroups for comparison with the cohort reported in 1984. Staging improved the outcome in patients with gradients greater than 40 mm Hg (mortality of 17% compared with 67% from 1984; p = 0.05). Patients with gradients from 10 to 25 mm Hg who had a single-stage operation had the best outcome (mortality 6%). Survival has improved. Many factors, including increased awareness of the detrimental effects of subaortic obstruction, improved surgical techniques, better perioperative care, and the appropriate application of a staged repair, have contributed to this improvement. We recommend simultaneous relief of obstruction and a modified Fontan operation for patients with subaortic gradients less than 25 mm Hg. Those with gradients greater than 40 mm Hg should have repair in two stages. It is unclear whether a one-stage or two-stage approach is better for patients with gradients between these extremes.