Trans-Catheter PDA Closure

April 25, 2024 - During the Neonatal Cardiology Academic Rounds at the Montreal Children's Hospital, Dr. Mohammed Alamer (Pediatric Interventional Cardiology Fellow) and Mrs. Laila Wazneh (Neonatal Nurse Practitioner) presented "Trans-Catheter Ductal Closure – What the NICU Should Know" to our group. This topic, a focal point of active research, involves considerable debate regarding the optimal timing, candidates, and methods for addressing patent ductus arteriosus (PDA) in premature infants in the NICU. They provided a thorough review of the practical considerations for trans-catheter ductal closure. The presentation is available here. This presentation was not intended to guide patient selection or promote a specific approach but offered insights into the realities and perspectives of interventional cardiologists concerning the procedure, the data available from published studies, and the aspects to monitor post-procedure if this method is chosen for certain patients. Our site practices a conservative approach to duct management in premature infants, pending further data from trials on mechanical closures using a trans-catheter method. We described a high spontaneous closure rate in our population with only about 10% of our cohort, who have large residual shunts that do not close spontaneously, with follow-up in cardiology, and intervention considered by a handful of these patients from our cardiology colleagues just before or after discharge.

25 avril 2024 - Lors des séances académiques de cardiologie néonatale à l'Hôpital de Montréal pour enfants, le Dr Mohammed Alamer (fellow en cardiologie pédiatrique et interventionnelle) et Mme Laila Wazneh (infirmière praticienne néonatale) ont présenté à notre groupe "Fermeture ductale par cathéter - Que doit savoir la NICU ?". Ce sujet, au cœur de recherches actives, suscite de vifs débats concernant les candidats appropriés, le moment optimal et les méthodes pour traiter le canal artériel persistant (CAP) chez les prématurés en NICU. Ils ont effectué une revue approfondie des considérations pratiques concernant la fermeture ductale par cathéter. Cette présentation est disponible ici. Cette présentation n'avait pas pour but de fournir des directives sur la sélection des patients ni de préconiser une approche spécifique, mais elle a offert des perspectives sur la réalité et le point de vue des cardiologues interventionnels concernant la procédure, les données disponibles issues des études publiées et les éléments à surveiller après la procédure si cette méthode est choisie pour certains patients. Nous avons une approche conservatrice de la gestion du canal chez les prématurés, en attente de données supplémentaires issues d'essais sur les fermetures mécaniques par méthode trans-cathéter. Nous avons décrit un taux de fermeture spontanée élevé dans notre population avec seulement environ 10 % de notre cohorte, qui présentent des shunts résiduels importants qui ne se ferment pas spontanément, avec un suivi en cardiologie et une intervention envisagée par une poignée de ces patients de la part de nos collègues en cardiologie. juste avant ou après la sortie.

Complications of Persistent PDA in term or post-term infants:

If a large PDA persists and causes significant left heart dilation, it can ultimately lead to cardiac failure. Long-term, unrepaired large shunts can cause permanent damage to the pulmonary arteries, leading to pulmonary hypertension and potentially Eisenmenger syndrome. PDA is also a predisposing factor for infective endocarditis due to turbulent blood flow. Less commonly, especially in adults, aneurysms of the ductus arteriosus and aortic dissections have been described.

Treatment of Persistent PDA

Historically, surgical ligation or section/suture was the preferred treatment for PDA. The first surgical closures date back to the early 20th century, and surgery remained the primary option until the late 20th century, including for premature infants from the 1970s. The surgical approach typically involves a left posterolateral thoracotomy, allowing access to the ductus under the scapula. Surgical complications can include haemorrhage due to proximity to large vessels. There is also a risk of nerve damage, particularly to the left recurrent laryngeal nerve (leading to vocal cord paresis or paralysis) and the left phrenic nerve (causing diaphragmatic paralysis). Injury to the thoracic duct, which drains lymph, can result in chylothorax (persistent fatty drainage). Although rare, inadvertent coarctation of the aorta or closure of the left pulmonary artery or aortic arch during surgery has been reported. In premature infants, surgery can significantly major their haemodynamic and respiratory instability due to positioning and manipulation of the lung. Currently, percutaneous closure via catheterization is the emerging standard for treating PDA in most patients at term or post-term. The first descriptions of catheter-based closure date back to the 1990s. This method avoids a surgical scar and allows for the closure of increasingly larger ducts in smaller infants using a variety of available prostheses, such as Amplatzer Duct Occluders (ADO 1, ADO 2, Piccolo) or coils.

Indications for PDA closure in term or term-corrected age newborns generally include:

• Symptomatic PDAs or large PDAs with evidence of significant Qp:Qs (e.g., left heart dilation).

• It is contraindicated to close a PDA that is bidirectional or exclusively right-to-left, as this indicates severe pulmonary hypertension where the ductus acts as a vital "safety pop-off valve".

Complications of percutaneous closure include:

• Prosthesis migration or embolization, which can obstruct the pulmonary artery or aorta.

• Iatrogenic coarctation or left pulmonary artery stenosis if the prosthesis is too large or extends beyond the ductal opening.

• Residual shunts (either through or around the prosthesis) are common but often resolve. However, persistent periprosthetic shunts may indicate an inappropriate prosthesis choice. Residual shunts can also cause haemolysis.

• Local complications at the access site, such as aneurysms, arteriovenous fistulas, or haematomas. Vascular injury to the limb. 

• Infections, bleeding. 

• Anesthesia complication.

• Valvular injury, myocardial injury. 

• Tricuspid regurgitation (due to guide wire trauma to chordae or leaflets). Other risks include failure to close the ductus (if it's very spastic or large, or if closure risks creating a coarctation or pulmonary artery stenosis), prosthesis embolization, and local access site complications.

• The success rate of percutaneous closure is generally over 95%. Recent advancements include the increasing use of venous access instead of arterial access (especially in small infants) to reduce the risk of arterial complications. Miniaturized and standardized equipment has enabled closure in very small infants. The ultimate goal is to perform echo-guided closures without the need for contrast injections or X-ray radiation.

• For specific ductus-dependent congenital heart conditions (e.g., tricuspid atresia, pulmonary atresia), it may be necessary to keep the ductus arteriosus open. This can be achieved through stenting of the ductus via catheterization. However, these stents often require repeated redilations as the child grows.