A fenestration in the atrial septum may be temporarily beneficial in high–risk patients undergoing the modified Fontan operation. The venous system is decompressed into the left atrial cavities resulting in an improvement in the systemic output at the expense of a moderate arterial desaturation due to a right–to–left shunt. Two groups of patients undergoing the modified Fontan operation were compared. Those treated with the classic operation (non–fenestrated Fontan group, n=56) had lower prevalence of preoperative risk factors for the Fontan operation than those undergoing the Fontan operation with a fenestrated patch (n=91). Nevertheless, early results of mortality, repair take–down and morbidity (duration of pleuropericardial effusions) were comparable or better in the fenestrated Fontan group. By regression analysis the presence of a fenestrated patch was the major determinant in the reduction in the amount and duration of postoperative effusion. Of the early 73 survivors in the fenestrated Fontan group, fifty tolerated the closure of the fenestration, which occurred either spontaneously (five cases) or was achieved by a clamshell device during cardiac catheterization. Eleven patients failed the first attempt at fenestration closure, but this was successful at the second attempt a few months later. Coil embolization of arterial collaterals to the lung circulation and balloon dilatation of pulmonary artery stenoses were required in some cases. Other patients following the Fontan operation with a fenestrated patch showed an improvement of their ventricular function which was initially impaired. This favorable experience demonstrates the usefulness of the “fenestrated Fontan approach” in patients who are suboptimal candidates for the classic operation, provided that the preoperative risk factors are potentially reversible.

We found right-to-left shunts through the cardiac veins postoperatively in 2 patients who had undergone the Fontan procedure. In one of the patients, channels were present through the cardiac veins independent of the coronary sinus. In the other patient, an atretic orifice for the coronary sinus, coupled with a persistent left-sided superior caval vein, complicated the postoperative course.