Andersons pediatric cardiology 444

Overall, transcatheter interventions for pulmonary vein stenosis can be highly successful in relieving gradients and improving lumen caliber, although midterm outcomes and survival remai

FIG 18.25 Systemic venous obstruction, with stents implanted in the obstructed superior and inferior caval pathways in a patient with a Mustard

procedure.

Pulmonary Venous Stenosis

Pulmonary venous stenosis can be idiopathic, most commonly in neonates with a history of chronic lung disease, or can follow surgical repair of anomalous

pulmonary venous drainage, with or without other congenital cardiac disease There has been an increasing awareness of the condition as an isolated entity, particularly in premature infants In infants and children, pulmonary

hypertension and right-sided cardiac failure manifest over time When present in

young children, pulmonary vein stenosis is usually a progressive and life-threatening disease Overall, transcatheter interventions for pulmonary vein stenosis can be highly successful in relieving gradients and improving lumen caliber, although midterm outcomes and survival remain disappointing.163,164 The transcatheter approach includes use of chronic thrombotic obstruction wires

to recanalize atretic pulmonary veins, use of cutting balloons to “score” stenotic pulmonary veins, implantation of premounted—or rarely large-diameter

unmounted—stents, implantation of drug-eluting stents, and use of drug-coated balloons There has been recent interest in immunomodulatory therapy,

administered either systemically or locally.165–167 Hence many practitioners have

vessels, with use of drug-coated balloons (usually paclitaxel eluting) for larger diameter pulmonary veins Overall, midterm outcomes for intervention in

pulmonary vein stenosis in infants remain disappointing, with 2-year survival approaching 60% in recent surveys.163 Reintervention to maintain patency of pulmonary veins appears to be essential to improving outcomes

In older children and adults, the etiology of pulmonary vein stenosis is quite different and may reflect compression, particularly in the setting of heterotaxy syndrome, where the pulmonary veins can be compressed between the cardiac mass and the descending aorta, or by a mediastinal mass, or following

interventional or surgical treatment of atrial arrhythmia In both the congenital and acquired forms of pulmonary venous stenosis, histologic findings show neointimal proliferation leading to occlusion of the lumen of one or more

pulmonary veins.168

Stenting of the Arterial Duct.

Stenting of arterial duct for duct-dependent systemic and pulmonary circulations was first introduced by Gibbs et al in 1991169 but has made a resurgence with improvements in technology and advances in interventional catheterization Infants with a variety of CHD lesions may benefit from ductal stenting Patients with pulmonary atresia and intact ventricular septum, tetralogy of Fallot, and forms of transposition of the great arteries and tricuspid atresia with pulmonary stenosis may often benefit from ductal stenting The most commonly used stents are premounted coronary arterial stents of 3- to 4-mm diameter The chosen length varies by patient anatomy, although operators understand inherently that the entire length of the arterial duct must be stented to prevent spontaneous ductal closure once prostaglandin infusion is discontinued

The arterial duct should demonstrate some constriction to provide an ideal landing zone for the ductal stent, and this may require cessation of prostaglandin prior to procedure Access for delivery of the ductal stent varies from femoral arterial, femoral venous, umbilical artery, or even carotid arterial or axillary arterial Increasingly, operators are using the carotid artery for percutaneous stenting of the arterial duct, especially in cases of a highly tortuous superiorly oriented arterial duct.170 Aortography is performed to identify ductal

morphology, noting its diameter and length, and to identify landmarks for

implantation of the stent (Fig 18.26) A coronary arterial guidewire is passed through the duct, and the stent is delivered through a sheath or coronary guide

satisfactory position of the stent along the entire length of the arterial duct The length of the stent is usually 1 to 2 mm longer than the ductal length, so as to cover both the aortic and pulmonary arterial ends of the duct Jailing of one of the branch pulmonary arteries and partial protrusion of the stent out into the aortic arch should ideally be avoided However, side-branch PA jailing may occur and can be dealt with at time of ductal stenting with stent side-cell

angioplasty to the affected side or even with placement of a second coronary stent to the affected branch PA After deployment, aortography confirms the adequate patency of the duct and the stent Placement of more than one ductal stent is frequently necessary, to cover the entire length of the arterial duct,

especially in cases of significant ductal tortuosity Prostaglandin is discontinued, and the patient is commenced on an antiplatelet therapy Recent multicenter data indicate that ductal stenting outcomes rival surgical palliation methods.171 Risks associated with stenting of the arterial duct include progressive occlusion of the ductal stent with neointimal proliferation, and in nearly 40% of cases,

reintervention by 3 months is necessary.171,172 Consideration is currently being given to the use of drug-eluting coronary stents in an effort to decrease the rate and degree of neointimal proliferation.173

FIG 18.26 Ductal stenting in a patient with pulmonary atresia and intact

ventricular septum following perforation and dilation of the pulmonary valve (A) The lateral projection of the aortogram outlines the restrictive

arterial duct (B) The stent is positioned in the arterial duct from the pulmonary artery with check aortography (C) There is good flow through

the duct after implantation.

Removal of Foreign Bodies or Devices From the Circulation.