*2.2.7 Device closure of Fontan fenestration*

Patients who have undergone a fenestrated Fontan operation or patients who have a residual atrial defect, despite correction, may have clinically significant right-to-left shunt causing varying degrees of hypoxemia. These residual defects should be closed not only to address arterial desaturation but also for prevention of paradoxical embolism [30, 31]. Although two types of fenestration closure, namely, constriction of the preplaced suture in the postoperative period [26, 28] and device closure later [27] were described, device closure is opted at most institutions. Closure of such defects can be performed by using transcatheter techniques [32–35]. The procedure is usually performed 6–12 months following fenestrated Fontan procedure. Although a number of devices have been used in the past [32–35], at the present time, Amplatzer septal occluders are the most commonly used devices to accomplish such closures.
