Stenting of Central Aortopulmonary Shunt in a Child With Pulmonary Atresia, Ventricular Septal Defect, and Severely Hypoplastic Pulmonary Arteries

ABSTRACT: A male infant was born at 28 weeks gestation weighing 850 g. He was diagnosed with pulmonary atresia, ventricular septal defect and major aortopulmonary collaterals with severely hypoplastic true pulmonary arteries. A 3.5 mm Gore-Tex central shunt was anastomosed from the ascending aorta to the main pulmonary artery at 4 months of age and a weight of 3.5 kg. The left pulmonary artery measured 1-2 mm and the right pulmonary artery measured 1 mm. His saturations increased from 70% to 85% following placement of the central shunt. At 16 months of age, his oxygen saturation decreased to 68%. Cardiac catheterization, using a retrograde approach, and angiography demonstrated a moderate degree of stenosis within the distal shunt and a severe left pulmonary arterial stenosis. A 4 x 18 mm Multi-Link Vision coronary stent was implanted within the stenotic central shunt and angioplasty of the left pulmonary arterial stenosis was performed. The oxygen saturation improved to 84% after the procedure. Although stenting of the Blalock-Taussig shunt has been described previously, this represents one of the first reports of stenting of a central aortopulmonary shunt. This significantly improved the patient’s oxygen saturation and allowed the potential for some further central pulmonary arterial growth prior to unifocalization procedure.

J INVASIVE CARDIOL 2013;25(12):E216-E218

Key words: major aortopulmonary collaterals, pulmonary atresia, hypoplastic pulmonary arteries, central shunt, Mee shunt, stent

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Infants with pulmonary atresia, ventricular septal defect (VSD), severely hypoplastic pulmonary arteries, and major aortopulmonary collateral arteries (MAPCAs) represent a dif- ficult cohort of patient to treat.^1,2 The placement of a central aortopulmonary (Mee) or Blalock-Taussig shunt is often part of the surgical strategy to encourage pulmonary arterial growth as a precursor to unifocalization and attempted septation.^3,4 Previously, stenting of stenotic Blalock-Taussig shunts has been described when they develop significant in-shunt stenosis.^5,6 In this report, we describe stenting of a stenotic central aortopulmonary shunt in a child with pulmonary atresia, VSD, MAPCAs, and severely hypoplastic branch pulmonary arteries.

Case Report. A male infant was born at 28 weeks gestation weighing 850 g. The baby was noted to be cyanosed and satura- tions measured 73% in upper and lower limbs. There was a 1-2/6 continuous murmur heard at the back. The brachial and femoral pulses were normal. Echocardiography confirmed visceral situs solitus and levocardia. There was normal systemic and pulmonary venous drainage. There was pulmonary atresia and VSD with severely hypoplastic pulmonary arteries. The aortic arch was right sided with collaterals arising from the aorta. Co-existent morbidities in the child included grade-1 intraventricular hemorrhage, hypothyroidism, chronic lung disease, and two episodes of E. coli septicemia. FISH screening for 22q11 deletion was negative. Cardiac catheterization was performed at 14 weeks of age and demonstrated the aforementioned anatomy with severely hypoplastic branch pulmonary arteries measuring 1-2 mm. There were two major collaterals arising from the mid-descending aorta with one supplying each ipsilateral lung. There was a small aortopulmonary collateral supplying the posterior basal segment of the left lower lung.

At 4 months of age, the child underwent surgical placement of a 3.5 mm Gore-Tex tube from the undersurface of the ascending aorta to the main pulmonary artery (Mee shunt). At the time of surgery, the severely hypoplastic size of the pulmonary arteries was confirmed. The oxygen saturation increased from 72% to 84% following shunt placement. The child continued to grow and develop appropriately. It was decided to defer unifocalization until the central pulmonary arteries demonstrated some further growth and the child was a larger size.

At 16 months of age, his oxygen saturation decreased to 68%. Cardiac catheterization was undertaken. Access was obtained using the Seldinger technique. A 5 Fr sheath (Cordis Corporation) was placed in the right femoral vein and the right femoral artery. Using a retrograde approach, a 4 Fr JR catheter (Merit Medical) was used to perform an angiogram in the descending aorta confirming the MAPCA anatomy and the hypoplastic branch pulmonary arteries (Figure 1). Selective angiography in the central aortopulmonary shunt demonstrated a moderate degree of stenosis within the distal shunt, severe stenosis of the left pulmonary artery, and a mild degree of origin stenosis of the right pulmonary artery (Figures 2A and 2B). A 5 Fr JR guide catheter was used to deploy a 4 x 18 mm Multi-Link Vision coronary stent (Abbott Vascular) within the stenotic central shunt (Figure 3) and angioplasty of the main to left pulmonary arterial stenosis was performed (Figure 4). There was complete alleviation of the stenosis within the shunt and significant improvement of the main pulmonary artery to left pulmonary artery stenosis (Figure 5). The oxygen saturation im-proved to 84%.

Discussion. In children with pulmonary atresia, VSD, MAPCAs, and severely hypoplastic pulmonary arteries, placement of a central or Blalock-Taussig shunt may allow central pulmonary arterial growth as a staged approach prior to unifocalization and attempted septation.^3,4 Some patients will demonstrate significant growth in the central pulmonary arteries; however, in some patients, pulmonary arterial growth may be insignificant, as in this patient. Previous reports have highlighted the potential to stent a Blalock-Taussig shunt where there is shunt stenosis.^5,6 This report highlights the potential for stenting of a stenotic central aortopulmonary shunt in this complex anatomy.

This resulted in a significant improvement in the patient’s oxygen saturations and at the same time allowed for balloon angioplasty of the stenotic main and left pulmonary arteries. Technically, the procedure was not challenging and given the multiple sources of pulmonary blood flow in the patient, crossing and stenting of the shunt was very well tolerated. This may prove to assist in further growth of the central pulmonary arteries or at least optimize the patient hemodynamically prior to attempted unifocalization. Interestingly, the stent expanded the shunt up to 4 mm, beyond the 3.5 mm size of the shunt, also indicating that there is a degree of distensibility within the Gore-Tex tube employed in such shunts.

Conclusion. This report highlights the potential to achieve good shunt rehabilitation following central shunt stenosis using stent placement in a difficult-to-treat patient cohort. Stenting of a stenotic central aortopulmonary shunt improves oxygen saturation as in this patient, may augment further pulmonary arterial growth, and may potentially improve outcome in such patients.

Acknowledgment. We are grateful to Mr Andrew Pendred for assistance in preparation of the figure illustrations for this manuscript. We are grateful to Ms Deirdre Devlin for assistance in manuscript preparation.

References

1. Reddy VM, McElhinney DB, Amin Z, et al. Early and intermediate outcomes after repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: experience with 85 patients. Circulation. 2000;101(15):1826-1832.
2. Metras D, Chetaille P, Kreitmann B, et al. Pulmonary atresia with ventricular septal defect, extremely hypoplastic pulmonary arteries, major aortopulmonary collaterals. Eur J Cardiothorac Surg. 2001;20(3):590-596.
3. Ilbawi MN, Grieco J, DeLeon SJ, et al. Modified Blalock Taussig shunt in newborn infants. J Thorac Cardiovasc Surg. 1984;88(5 Pt 1):770-775.
4. Watterson KG, Wilkinson JL, Karl TR, Mee RB. Very small pulmonary arteries: central end-to-side shunt. Ann Thorac Surg. 1991;52(5):1132- 1137.
5. Kouatli A, Al-Ata J, Galal MO, et al. Stent implantation to maintain pa- tency of a stenosed Blalock-Taussig shunt. Asian Cardiovasc Thorac Ann. 2005;13(3):274-276.
6. El Said HG, Clapp S, Fagan TE, et al. Stenting of stenosed aortopulmonary collaterals and shunts for palliation of pulmonary atresia/ventricular septal defect. Catheter Cardiovasc Interv. 2000;49(4):430-436.

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From the Department of Pediatric Cardiology, Our Lady’s Children’s Hospital, Crumlin, Dublin, Ireland.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted May 8, 2013, provisional acceptance given June 2, 2013, final version accepted June 6, 2013.

Address for correspondence: Dr Colin J. McMahon, FRCPI, Cardiac Department, Our Lady’s Children’s Hospital, Crumlin, Dublin 12, Ireland. Email: cmcmahon992004@yahoo.com