- Kevin P Walsh, consultant paediatric cardiologist
- Our Lady's Hospital for Sick Children, Crumlin, Dublin, Republic of Ireland.
Interventional paediatric cardiology mainly involves dilatation of stenotic vessels or valves and occlusion of abnormal communications. Many transcatheter techniques—such as balloon dilatation, stent implantation, and coil occlusion—have been adapted from adult practice. Devices to occlude septal defects, developed primarily for children, have also found application in adults.
Interventional procedures follow a common method. General anaesthesia or sedation is required, and most procedures start with percutaneous femoral access. Haemodynamic measurements and angiograms may further delineate the anatomy or lesion severity. A catheter is passed across the stenosis or abnormal communication. A guidewire is then passed through the catheter to provide a track over which therapeutic devices are delivered. Balloon catheters are threaded directly, whereas stents and occlusion devices are protected or constrained within long plastic sheaths.
Balloon atrial septostomy, introduced by Rashkind 35 years ago, improves mixing of oxygenated and deoxygenated blood in patients with transposition physiology or in those requiring venting of an atrium with restricted outflow. Atrial septostomy outside the neonatal period, when the atrial septum is much tougher, is done by first cutting the atrial septum with a blade.
Pulmonary valve stenosis
Balloon valvuloplasty has become the treatment of choice for pulmonary valve stenosis in all age groups. It relieves the stenosis by tearing the valve, and the resultant pulmonary regurgitation is mild and well tolerated. Surgery is used only for dysplastic valves in patients with Noonan's syndrome, who have small valve rings and require a patch to enlarge the annulus.
Valvuloplasty is especially useful in neonates with critical pulmonary stenosis, where traditional surgery carried a high mortality. In neonates with the more extreme form of pulmonary atresia with an intact ventricular septum, valvuloplasty can still be done by first perforating the pulmonary valve with a hot wire. Pulmonary valvuloplasty can also alleviate cyanotic spells in patients with tetralogy of Fallot …