Fontan fenestration allows right-to-left shunting increasing cardiac output and oxygen delivery. Increased shunting occurs as cardiac function and ventricular end-diastolic pressures improve, potentially decreasing oxygen saturation. Complete closure may result in impaired Fontan haemodynamics and low cardiac output; however, there are no dedicated devices to reduce fenestration size. We describe Fontan fenestration size reduction using the Atrial Flow Regulator.

Interventional cardiology plays a key role in the diagnosis and management of patients with functionally univentricular physiology after the various stages of surgical palliation. The interventions performed are widely variable in type, including angioplasty of stenotic vessels and implantation of stents in stenotic vessels; closure of defects such as collaterals, leaks in baffles, and fenestrations; creation of fenestration; and more. In the setting of venous hypertension associated with stenosis at the Fontan baffle, conduit, or pulmonary arteries, stent implantation is often preferred, as the aim is to eliminate completely the narrowing, given that relatively mild stenosis can have a significant detrimental hemodynamic effect in patients with functionally univentricular circulation. The procedure is highly successful. In patients who fail after Fontan procedure, creation of a fenestration is often performed, with variable technique depending on the underlying anatomic substrate. To increase chances of patency of the fenestration, implantation of a stent is often required, particularly in the setting of an extracardiac conduit. For those patients with cyanosis and favorable Fontan hemodynamics, closure of the fenestration is performed using atrial septal occluder devices with high success rate. Coils compatible with magnetic resonance imaging are used widely to treat collateral vessels, although on occasion other specific embolization tools are required, such as particles or vascular plugs. Postoperative arch obstruction is successfully managed with angioplasty at a younger age, while implantation of a stent in the aorta is reserved for older patients. Specifics of these interventional procedures as applied to the population of patients with functionally univentricular hearts are described in this manuscript.

The Amplatzer Septal Occluder is made from a Nitinol wire mesh shaped into 2 disks with a connecting waist, which serves to center the device in the defect while occluding it. The Amplatzer device is also available in a configuration with no central waist for use in patients with patent oval foramen, or multiperforated aneurysm of the interatrial septum. For the purposes of this review, we analysed our experience using the Amplatzer device in 150 patients with interatrial communications. Of these, 104 had a defect within the oval fossa, 33 a patent oval foramen, and 13 had undergone fenestration of a Fontan procedure. Of those with defects within the oval fossa, a device was implanted in 100 patients, and 2 of these patients subsequently required surgical intervention, 1 because of migration and the other because of malformation of the device. Of the remaining 98 patients, complete occlusion has been achieved in 90% at 1 year. Any residual leaks are either trivial or small. In those with a patent oval foramen, the septal occluder was used to close 20, whilst the device designed specifically for this purpose was used in 13. On follow-up contrast echocardiography, only 2 patients have a small residual right-to-left shunt. Complete occlusion was achieved for all the Fontan fenestrations, although 1 patient later underwent surgery for baffle dehiscence. Other significant complications occurred in 2 patients who developed deep vein thrombosis, and 3 patients who suffered transient supraventicular arrhythmias. Although the Amplatzer device has been in clinical use for only 3 years, its unique design, and ease of use, has resulted in its widespread adoption by many entres. The results to date are very encouraging, but it must be remembered that there is, as yet, no long-term followup data available for this life-long implant.