Staged Fontan operation for complex cardiac anomalies with subaortic obstruction.

Ventricular hypertrophy is a recognized risk factor for the Fontan operation in cases of complex cardiac anomalies with unrestricted pulmonary blood flow and subaortic obstruction. Between 1986 and 1991 we have treated 23 such patients with a new type of palliation combining a main pulmonary artery-ascending aorta anastomosis with a bidirectional cavopulmonary anastomosis. Their ages averaged 57 +/- 36 months (7 to 155 months). Nine patients had (S,L,L) single ventricule with transposition and the other 14 had more complex cardiac anomalies unsuitable for biventricular repair. Subaortic obstruction was defined by a hemodynamic criterion (n = 6) or by a morphologic criterion (n = 17). There were five hospital deaths (21.7%): All three patients older than 7 years of age died (p = not significant). Follow-up averaged 28 +/- 21 months (range 1 to 58 months). Among the 18 hospital survivors, the proportions surviving 1 and 5 years after the operation were 78% and 63%, respectively. Control cardiac catheterization in 11 patients showed no or trivial subaortic gradient, a mean cavopulmonary pressure of 10 +/- 3 mm Hg, and a mean arterial oxygen saturation of 83%. Nine patients underwent secondary Fontan repair in our institution 21 +/- 4 months after palliation, without deaths. Another patient died elsewhere, 3.7 years after palliation, as a result of hemorrhage at sternal reentry during attempted Fontan operation (overall mortality at repair, 10%). The other eight patients are awaiting Fontan operation. This staged approach reduces both pressure and volume ventricular load and provides adequate oxygenation before the Fontan operation. In our experience, it resulted in reduced mortality at definitive repair.