Use of self expanding stents in stenotic aortopulmonary shunts in adults with complex cyanotic heart disease

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.

Off-Label use of Stretchable Polytetrafluoroethylene: Overexpansion of Synthetic Shunts

Purpose

To describe our experience with balloon dilatation and stenting of modified systemic-to-pulmonary artery (PA) shunts in relation to an assessment and interpretation of the mechanical properties of thin-walled expandable polytetrafluoroethylene (ePTFE) stretch vascular grafts.

Methods

Our pediatric cardiology/cardiac surgery database was reviewed to identify all infants and children with a modified systemic-to-PA shunt who underwent cardiac catheterization. Reports and images were reviewed. Thin-walled stretchable and regular Gore-Tex® vascular grafts were mechanically compared using tensiometry.

Results

11 patients underwent dilatation or stenting procedures of a systemic-to-PA shunt. No major complications occurred and none of our patients died during or due to this intervention. High pressures in balloons and stents with diameters larger than the graft were used. Shunt diameters and oxygen saturation levels increased from 2.05 ± 1.25 mm to 4.75 ± 0.88 mm and with 12 ± 6.8%, respectively. In 6 patients re-catheterizations were performed. Four patients died, all with patent shunts. The fail-stress and the fail-strain in the circumferential direction of the stretchable graft were significantly higher than in the non-stretchable graft.

Conclusions

Dilatation and stenting of stenosed modified systemic-to-PA shunts is feasible and safe. Dilatation and stenting of these shunts to calibers larger than those provided by the manufacturer is possible. Results of our technical study posit a great advantage for the use of the thin-walled stretch configuration of ePTFE.

Percutaneous upsizing of a Blalock-Taussig shunt

Percutaneous upsizing of surgically placed Blalock-Taussig shunts is an uncommon practice. We report the case of an 8-month-old infant with single-ventricle physiology, who - due to comorbidities - was deemed unsuitable to proceed with Glenn operation. The 3.5-millimetre Blalock-Taussig shunt was stented successfully with a 5-millimetre pre-mounted stent, resulting in an increase in shunt diameter and oxygen saturation by nearly 30% and 10%, respectively.

Stenting of modified and classical Blalock-Taussig shunts--lessons learned from seven consecutive cases

In neonates and infants with a shunt-dependent pulmonary circulation, stenosis of the shunt needs to be treated aggressively to prevent a fatal outcome. We report the technique and outcome in seven consecutive neonates and infants with Blalock-Taussig shunt stenosis, who were treated with intraluminal stents. Stenting of classical or modified Blalock-Taussig shunts is technically feasible and can be used as a rescue procedure. Neointimal dissection is less likely compared with balloon angioplasty of the shunt alone.

Stent graft exclusion of a pseudoaneurysm in a Blalock-Taussig shunt

This case is the first report of slow-growing pseudoaneurysm after vessel dissection secondary to two stents implantation into classic Blalock Taussig shunt in a patient with pulmonary atresia and ventricular septal defect. Pseudoaneurysm was successfully excluded by a percutaneous approach with self-expandable stent graft deployment from the aorta to the middle of the Blalock Taussig shunt. Nearly 3 years after the procedure, the classic BT is patent, and there were no restenosis or thrombosis in spite of the very long length of the stented segment.

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.

Open-cell design stents in congenital heart disease: a comparison of IntraStent vs. Palmaz stents

Slotted stainless Palmaz stents (PS) remain the most commonly used in congenital heart disease (CHD). Limitations of PS include rigidity, foreshortening, poor conformability on expansion, balloon rupture, and jailing of side branches. Recently, stents with open-cell design (IntraStent; IS) in appropriate sizes for CHD have been introduced. We reviewed our experience with the IS, comparing performance with the PS in a retrospective nonrandomized, uncontrolled observational study. Between May 1999 and March 2001, 34 IS (10-36 mm) and 34 PS (10-40 mm) were implanted in 57 patients (3 months to 25 years old; median, 3.24 years) in congenital or postoperative lesions. There was no statistically significant difference between the two groups in efficacy, % diameter increase (162% +/- 203% for IS vs. 153% +/- 177% for PS), and % gradient reduction (69% +/- 23% for IS vs. 80% +/- 27% for PS). Other aspects of stent performance differed significantly (P < 0.05): PS forshortened more (mean 18% for PS vs. 0% for IS) and were associated with balloon rupture (9/34 for PS vs. 0/34 for IS; P = 0.002), but had no evidence of intimal protrusion in between struts (0/34 for PS vs. 14/34 for IS; P < 0.001) and no recoil > 15% (0/34 for PS vs. 7/34 for IS; P = 0.006); IS conformed almost twice as well to vessel curvature (P = 0.003). Although these factors did not affect immediate procedural success, balloon rupture in two PS resulted in stent malpositions. Among IS, the origins of three covered side branches were accessed and balloon dilated up to 6 mm through the side of the stent. In conclusion, stents with open-cell design have some characteristics that seem beneficial for their use in CHD: they foreshorten less, are conformable, are less likely to cause balloon rupture, and can allow access to jailed branches. However, they have a higher incidence of significant percent recoil and protrusion of intimal tissue in between struts, which may impact long-term stent performance.

Intravascular and intracardiac stents used in congenital heart disease

Intravascular or intracardiac stenoses occur in many forms of congenital heart disease or after attempted surgical repair. Although balloon dilation is one option for management, restenosis can occur due to elastic recoil immediately after the procedure. To address to such stenotic lesions, many reports support implanting endovascular stents to provide a framework for vessel expansion. Both balloon-expandable fixed tubular mesh stainless steel devices, and self-expandable stents have had an extensive clinical application. In pediatric patients, stents are used for a variety of stenoses, such as systemic venous obstruction pathways (eg, Mustard, Fontan baffle, or bidirectional cavopulmonary connections), pulmonary artery, right ventricular to pulmonary conduits, aortic coarctation, the arterial duct, aorticopulmonary collaterals, or postoperative systemic to pulmonary shunts. Because of improvements in device profile, implantation rates have increased. Complications such as stent fracture, migration, aneurysm formation, and in-stent restenosis occur but only rarely. This latter event may be because of intimal hyperplasia and/or continued vessel (and patient) growth related to the stent diameter. As such, some instances require redilation to manage the acquired lesion. Stent application has importantly altered management algorithms in congenital heart disease.