Initial Clinical Experience with the Express® LD stent to Treat Children with Congenital Heart Diseases

Background:
The Express LD® stent (Boston Scientific, Marlborough, MA) is a large diameter (6-10 mm), pre-mounted, bare metal, stainless steel stent with an open cell design that is FDA approved to treat atherosclerotic lesions in iliac arteries. This stent can be dilated up to 16-20 mm; beyond which it easily unzips as shown by previous in vitro and animal experiments. Therefore, this stent could potentially be implanted in children with the objective of re-dilating it as the child grows to adult size, or be unzipped with implantation of another large diameter stent within it. The objective of this study is to describe the early clinical experience of using the Express LD stent to treat children with congenital heart diseases (CHD).

Methods:
A Retrospective review was performed including children with CHD that had vessel stenosis treated with the Express LD stent between June 2014 and September 2018 from a single center.

Results:
There were a total of 26 attempted stent implantations in 16 patients (age 1 month – 16 yrs; median 3.5 yrs) during 20 separate procedures. The procedure success rate was 100%. Two patients had 3 stents, five had 2 stents and the rest had a single stent implanted. The stent sizes include 6 mm (n=2), 8 mm (n=11), 9 mm (n=4) and 10 mm (n=9) at the time of implantation. The most common location for stent implantation was the pulmonary arteries (n=16), followed by the aorta (n=7). At most recent follow up (median = 19 months), ten patients (with 15 stents) have had 18 subsequent catheterization procedures. Seven stents have so far required re-dilations for recurrent stenosis. There has been no procedure related serious adverse events or during the early follow-up period.

Conclusions:
It is feasible to use the Express LD stent to treat stenotic vessels in children with CHD with no adverse events on short term follow-up. This stent has the potential to be re-dilated to adult vessel sizes as the child grows and can also be easily unzipped if necessary. These properties could make this stent ideally suited for implantation within growing blood vessels. The Express LD stent could therefore add to the existing repertoire of pre-mounted stents currently used in children with CHD.