Stenting of stenosed aortopulmonary collaterals and shunts for palliation of pulmonary atresia/ventricular septal defect

Basic Concepts and Insights into Aortopulmonary Collateral Arteries in Congenital Heart Diseases

Aortopulmonary collateral arteries are persistent embryological vessels supplying lung parenchyma in various cardiopulmonary diseases with underlying pulmonary hypoperfusion. Their identification and mapping are important because of associated clinical implications and tendency to affect the surgical outcome. This article describes the embryological development and clinical relevance of aortopulmonary collaterals in various congenital cardiopulmonary conditions, along with the significance for treatment planning. Roles, strength, and shortcomings of the various imaging options and image-guided interventions are discussed, with a focus on presurgical planning and preparation, as well as postsurgical management.

Percutaneous stent implantation for occluded central shunts in adults: A case report and review of current evidence

Background

Patients with cyanotic complex congenital heart defects (CHDs) commonly undergo palliation with interposition of systemic-to-pulmonary shunts (SPSs). These palliative shunts are rarely found in adults with CHDs and can be complicated with progressive obstruction or total occlusion during follow-up. The best treatment option for shunt re-permeabilization is challenging and case-oriented because most patients are high risk candidates for redo surgeries. We aimed to review the current evidence on percutaneous stent implantation to treat failed SPSs.

Methods

We performed a comprehensive literature review on percutaneous stent implantation to treat failed and occluded SPSs. We also reported the case of a 33-year-old man with cyanotic CHD and a occluded central aorto-pulmonary shunt, who was successfully treated with percutaneous balloon dilatation and subsequently stent implantation at our institution.

Result

We identified and included 31 articles reporting on 150 patients and 165 stent implantations in failed SPSs. The age of patients at the time of stent implantation ranged from 6 days to 47 years. The time between the surgical shunt creation and transcatheter intervention ranged from 1 day to 17 years. Overall, 161/165 (97.5%) stent implantations were successful. The most common clinical presentation was cyanosis and decreased atrial oxygen saturations and the indication for stent implantation was shunt obstruction and stenosis.

Conclusion

This review highlights the benefits of endovascular stenting to permeabilize failed SPSs in children and adults with complex CHD who are classified as poor candidates for re-surgical repair.

Stent Implantation to Maintain Patency of a Stenosed Blalock Taussig Shunt

A 14-year-old female with complex congenital heart disease underwent a left-sided classical Blalock Taussig (BT) shunt 15 days after birth. Ten years after the operation her oxygen saturation had decreased significantly. An angiography revealed a severely stenosed BT shunt. Balloon dilation including implantation of a 6 × 13 mm stent was performed successfully. Immediately after intervention, oxygen saturation rose from 55% to 80 84% in room air. Follow-up at a year and a half later showed the classical BT shunt was still patent.

Role of stents in congenital heart disease

For more than 10 years, balloon-expandable intravascular stents have become an integral part of treatment for obstructive vascular lesions in children and adults with congenital heart disease. The initial problems with stents, such as sharp edges, rigid frame and unacceptable shortening when over-expanded have been overcome to a large extent with the newer designs. The problems related to delivery of stents, such as stent migration, balloon rupture, flaring of the edges of the stent, rupture of vessels and milking of the stent off the balloon, have also been overcome by newer designs of balloons. The failure of growth of balloon-expandable stents with the growth of the child is managed by redilation with or without additional stenting and newer growth stents. Self-expanding stents are not appropriate for use in growing children due to the limitation of their maximum diameters. The development of biodegradable stents may overcome these disadvantages in the future. Various new developments have recently occurred. Covered stents are ideal for treating acute vessel rupture and in isolating vascular aneurysms. Drug-eluting stents may prevent restenosis, but have not been used in children. Valved stents are a recent innovation for the treatment of regurgitant pulmonary valves.

Stenting an aortopulmonary conduit with peripheral cardiopulmonary bypass support

Although surgically created aortopulmonary (AP) shunts are uncommon in the adult congenital heart disease population, they are often used in patients with pulmonary atresia. For these patients, the shunt is a vital supply of pulmonary blood flow and thus obstruction of the shunt may lead to pulmonary hypoperfusion and hypoxia thereby increasing morbidity and mortality. This report describes a safe and effective method of stenting the conduit with the hemodynamic support of peripheral cardiopulmonary bypass (PCB). Prior to the procedure, a multimodality assessment of a stenosis in a kinked AP conduit using computed tomography, angiography, intravascular ultrasound (IVUS), and pressure wire assessment (PWA) was utilized. While PCB, IVUS, and PWA have all been used to great effect in various clinical scenarios, the combined use of these techniques has not been previously been described in the setting of intervention in adult congenital heart disease.

Stent implantation into vertical arterial duct in adult patient with cyanotic congenital heart disease

A 26-year-old patient, who has double inlet left ventricle, pulmonary atresia, and a patent vertical arterial duct, presented with progressive cyanosis with an arterial oxygen saturation of 71%. He had had three shunt operations and only the last aortopulmonary shunt was patent. Angiography revealed a stenotic aortopulmonary shunt, stenotic vertical arterial duct, and a branch stenosis of the left pulmonary artery. He underwent successful stent implantation into both the aortopulmonary shunt and vertical arterial duct and his arterial oxygen saturation increased to 88%. This case report illustrates that stent implantation into a vertical arterial duct is feasible and can be an alternative to shunt operation.

Stent implantation in right-sided patent ductus arteriosus to relieve severe cyanosis in adult patient with pulmonary atresia and ventricular septal defect

Patients with unrepaired pulmonary atresia and ventricular septal defect may develop stenosis of collaterals or shunts to the pulmonary arteries leading to hypoperfusion of lungs and systemic hypoxemia. A 25-year-old female with pulmonary atresia and ventricular septal defect presented with progressively increasing cyanosis and exercise intolerance. A restrictive right-sided patent ductus arteriosus was identified as the main source of pulmonary blood flow. We report transcatheter implantation of a balloon-expandable stent across the stenosed duct to augment the pulmonary blood flow as a palliative management option. Patient had immediate improvement in arterial oxygen saturation from 66% to 85% with excellent clinical improvement and stable oxygen saturation on 8 months of follow-up.

Assessment of the anomalous pulmonary circulation by dynamic contrast-enhanced MR angiography in under four seconds

The purpose of this study was to demonstrate the initial results of the dynamic contrast-enhanced MRA in under four seconds in the assessment of anomalous pulmonary circulation. We performed dynamic contrast enhanced MRA on ten patients with a temporal resolution of 2-3 sec for each phase. Five patients had pulmonary vascular anomaly and five patients had reconstructed pulmonary circulation. On nine patients catheter angiography was performed for the correlation. Dynamic contrast-enhanced MRA successfully demonstrated congenital pulmonary vascular anomalies and the pathway of anomalous pulmonary circulation in our series. With the improved temporal and spatial resolution, the dynamic contrast-enhanced MRA can be used in children and infants for the assessment of congenital vascular disease.