Treatment of Severe Native Left Pulmonary Artery Stenosis With Coronary Stent Implantation in a 2.4 kg Neonate

J INVASIVE CARDIOL 2017;29(9):E105-E106.

Key words: cardiac imaging, neonatal cardiology

A 1-month-old, 2.4 kg infant, previously born at 32 weeks gestation, was found to have a murmur while in the neonatal intensive care unit. The patient had ongoing feeding intolerance and required supplemental oxygen via nasal cannula. Cardiac computed tomography showed discrete stenosis of the proximal left pulmonary artery (LPA) with a normal-sized distal LPA (Figure 1). The patient underwent cardiac catheterization and a 4 x 9 mm Integrity coronary stent (Medtronic) was expanded to 10 atm across the stenotic proximal LPA with good result. Figure 2 shows angiographic images before and after stent placement. The stent was delivered via 4 Fr, 45 cm, hydrophilic Flexor sheath (Cook Medical) via femoral venous approach. The patient was discharged home several weeks after the catheterization on room air and tolerating oral feeds.  The patient was treated with enoxaparin for 2 weeks and then transitioned to aspirin for thrombotic prophylaxis.

We hypothesize that the LPA stenosis resulted from constriction of ductal tissue that extended onto the proximal LPA, as has been previously described.^1,2 The development of the murmur at several weeks of life and the normal-sized distal LPA support this hypothesis. The lesion was successfully treated with transcatheter coronary stent implantation. Coronary stents are low profile and can be delivered successfully into the branch pulmonary arteries of small, premature neonates.  As the patient grows, subsequent catheterizations will be needed to enlarge the stent to account for somatic growth. Once maximally dilated, the stent can then be fractured using ultra-high-pressure balloons to allow ongoing somatic growth or placement of a larger intravascular stent.^3,4 Transcatheter stent placement is an appealing option to treat discrete branch pulmonary artery stenosis in small, premature neonates in whom surgical treatment with arterioplasty can be challenging.

References

1.    Ziemer G, Luhmer I. Coarctation of the pulmonary artery in neonates. Prevalence, diagnosis, and surgical treatment.  J Thorac Cardiovasc Surg. 1993;106:889-894.

2.    Guntheroth WG. The role of ductal constriction in transient stenosis of the left pulmonary artery. Pediatr Cardiol. 1988;19:240-242.

3.    Morray BH, McElhinney DB, Marshall AC, Porras D. Intentional fracture of maximally dilated balloon-expandable pulmonary artery stents using ultra-high-pressure balloon angioplasty: a preliminary analysis.  Circ Cardiovasc Interv. 2016;9: e003281.

4.    Sathanandam SK, Haddad LM, Subramanian S, Wright D, Phillip R, Waller BR. Unzipping of small diameter stents: an in vitro study. Catheter Cardiovasc Interv. 2015;85:249-258.

From Carolinas HealthCare System, Charlotte, North Carolina.

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 accepted February 22, 2017.

Address for correspondence: Matthew C. Schwartz, MD, Carolinas HealthCare System, 1001 Blythe Blvd, Suite 200d, Charlotte, NC 28203-6215. Email: Matthew.C.Schwartz@carolinashealthcare.org