Modified Fontan procedure for biventricular hearts with complex forms of double-outlet right ventricle

The surgical management of patients with biventricular hearts and complex double-outlet right ventricle with noncommitted ventricular septal defect, hypoplastic ventricles, common atrioventricular orifice, stradding tricuspid valve, and straddling mitral valves is controversial. More recently at our institution, 23 of these patients underwent Fontan-type procedures as an alternative to the intraventricular tunnel repair. In all cases, the presence of more than one associated anomaly would have prevented adequate biventricular correction. The ventricular septal defects were of the inlet type in 14 patients, inlet and subpulmonary in one, multiple in one, subpulmonary in three, and subaortic in four. Twenty-one patients had atrioventricular junction anomalies, and 14 had hypoplastic ventricles (left ventricle in 11 and right ventricle in three). Pulmonary stenosis was present in 13 patients and pulmonary atresia in two. At operation, an extracardiac conduit was used in two patients and an atriopulmonary direct anastomosis in 21. There were six hospital deaths (26%). Seventeen patients had a mean follow-up period of 25 months. At the follow-up evaluation, nine patients were assigned to New York Heart Association Class I and seven to Class II; one patient assigned to Class IV died at 9 months postoperatively. Cumulative mortality was 30.4% (seven deaths). Univariate analysis identified hypoplastic left ventricle with any type of ventricular septal defect and atrioventricular junction as the only incremental risk factor for early and late outcome (p < 0.01), which also influenced functional status and use of drug therapy (p < 0.01) at the time of follow-up. The modified Fontan procedure offers improved results in the current surgical treatment of complex double-outlet right ventricle. However, in these patients, left ventricular hypoplasia still represents a significant negative prognostic feature.