ABSTRACT
Congenital heart diseases with duct-dependent circulation after birth are complex. Continued patency of the arterial duct (ductus arteriosus, DA) is essential in two major types of congenital heart disease: newborns with duct-dependent pulmonary blood flow who have a critically or totally obstructed ventricular-pulmonary connection, and neonates with duct-dependent systemic blood flow who require either a patent DA for the systemic circulation in total, which includes retrograde flow through the aortic arch for adequate coronary and cerebral blood flow, or to support partially the systemic blood flow in patients with multiple left heart obstructive lesions. Both duct-dependent systemic as well as pulmonary blood flow can be associated with a ‘single ventricle,’ as lacking two welldeveloped ventricles at birth, and also with a normal or borderline developed right or left ventricle with the option for biventricular repair. Blalock and Taussig1 were the first to create a surgical shunt as an alternative to the arterial duct. The modified BlalockTaussig shunt (mBTS) is still the most commonly created systemic-pulmonary shunt in neonates with cyanotic heart disease. Morbidity and mortality after mBTS are related to several factors including age, pulmonary artery diameter, and the baseline cardiac anatomy.2,3 Norwood et al.4 in 1981 reported the first experience in surgical reconstruction of the aortic arch combined with a modified Blalock-Taussig shunt. Such surgery in neonates, particularly in premature infants, can involve major complications, and despite improvements over the last decade both this and modified approaches still have significant mortality.5-7 In the past, attempts have been made to alter the native DA in various ways to maintain its patency. Formalin infiltration, and even balloon angioplasty and thermal balloon dilatation have been investigated, but long-term patency was disappointing.8-11
In 1991, the first experimental use of an intravascular stent to maintain ductal patency in an animal model was reported.12,13
Worldwide experience in stenting the DA in humans was quite limited in the last century.14 Previous attempts to stent the neonatal duct in humans used
early generation, rigid, bare stents, and relatively bulky, stiff wires, balloons, and sheaths, and frequently resulted in worsening cyanosis or shock, bleeding, vessel rupture, duct spasm, tissue prolapse, or acute thrombosis.15-17
Additionally, incomplete covering of the duct was frequently followed by duct constriction, with inadequate pulmonary or systemic flow within hours or days after implantation. Some indications for duct stenting were performed without a conclusive follow-up strategy. Based on these experiences, it was concluded that, for the majority of patients, ductal stenting could not be recommended due to the procedure risk and short duration of palliation.18 Duct stenting for newborns in ductdependent pulmonary circulation was apostrophized ‘a wanna-be’ Blalock-Taussig.19 By learning from these failures, and applying better patient selection criteria and preparation, using new techniques and better interventional access, and covering the complete length of the duct with current low-profile, flexible, premounted stents (with good scaffolding) or even self-expandable nitinol stents, the results of ductal stenting have been significantly improved. The ‘new era’ of duct stenting was started by the experience of Gerd Hausdorf and his team.20 Meanwhile, duct stenting is used worldwide in various forms of duct-dependent congenital heart defects.21-29 Duct stenting combined with bilateral banding as a percutaneous or intraoperative surgicalinterventional hybrid approach has been developed and nowadays established as an alternative for the classical Norwood approach.21,30-36
In the context of the current knowledge and literature,37 as well as based on our own experience of ductal stenting in more than 170 patients with ductdependent systemic (n = 115) and pulmonary (n = 59) circulation, this chapter deals with the technical aspects, including risk stratification and possible pitfalls of ductal stenting, to maintain pulmonary and systemic circulation.
