Experience of stent implantation for recurrent aortic arch obstruction following Norwood or Damus-Kaye-Stansel operation over the last decade

BACKGROUND

Recurrent aortic arch obstruction following the Norwood procedure is recognised as an important complication. Balloon arch angioplasty is associated with a high recoarctation rate.

METHODS

We sought to evaluate the prevalence and outcome of stent implantation for recoarctation in children following Norwood or Damus-Kaye-Stansel procedure over the past decade at a single national cardiology centre.

RESULTS

Of 114 children who underwent Norwood procedure or Damus-Kaye-Stansel procedure between January 2003 and June 2013, 80 patients survived. Of these 15 children underwent stent implantation for recoarctation. Six of these patients had previous balloon angioplasty. The median age at stent implantation was 4.4 months (range 2-82 months). The median peak aortic arch gradient at catheterisation decreased from 26mmHg (range 10-70mmHg) to 2mmHg (range 0-20mmHg). The median luminal diameter increased from 4.7 mm (range 3.2-7.9 mm) to 8.6 mm (range 6.2-10.9 mm). The median coarctation index increased by 0.49 (range = 0.24-0.64). A Valeo stent was employed in 11 children, a Palmaz Genesis stent in 2 patients, a MultiLink stent in 1 child, and a Jomed covered stent in 1 child. Two factors were associated with the need for stent placement: previous arch angioplasty (p valve < 0.001, χ-square 11.5) and borderline left ventricle (p = 0.04, χ-square = 4.1). Stent migration occurred in one child. There were two deaths related to poor right ventricular systolic function and severe tricuspid regurgitation. Six patients underwent redilation of the stent with no complications.

CONCLUSIONS

The prevalence of recurrent aortic arch obstruction following Norwood/Damus-Kaye-Stansel procedure was 18%. Stent implantation is safe and reliably eliminates the aortic obstruction. Redilation can be successfully achieved to accommodate somatic growth or development of stent recoarctation.

Dilating and fracturing side struts of open cell stents frequently used in pediatric cardiac interventions-An in vitro study

Background

Open cell stents are frequently used in interventional therapy of congenital heart disease. Overstenting of vessel branches may necessitate strut dilation.

Methods and Results

The strut size achievable in Bard Valeo and Cook Formula stents, and the pressure necessary to fracture struts was assessed. In addition, a self expanding stent (Optimed SinusflexDS) was also tested. With the original balloon at nominal pressure, in Valeo stents side struts could be dilated to approximately 90% of the nominal stent diameter, in Formula stents to approximately 80%. With larger high pressure woven balloons, strut size increased to approximately 125% in Valeo stents, and to approximately 105% in the Formula. Strut fracture can connect two adjoining struts. Pressures were dependent on the balloon utilized. Sidestruts of the Sinusflex could lastingly overdilated with large balloons only.

Conclusion

Dilation and overdilation of side struts in open cell stents can be achieved. Dependent on the clinical context, the original balloon used to place the premounted stent can be used to achieve strut dilation, but woven high pressure balloons maybe safer for patients. Should a larger diameter be required, these high pressure woven balloons can achieve bigger diameters and even strut fracture.

Stent Therapy for Aortic Coarctation in Children <30 kg: Use of the Low Profile Valeo Stent

To report our experience of coarctation stent therapy in small children weighing less than 30 kg, with the low profile dilatable Valeo stent and review the literature on coarctation stent therapy in this patient population. Coarctation stent implantation was undertaken in 14 consecutive children using the Bard Valeo Stent. Demographic, angiographic, echocardiographic and clinical data were reviewed retrospectively. The median age at the time of procedure was 5.1 (2.6-7.5) years and median weight was 20.8 (14.7-27) kg. There was improvement in median coarctation diameter from 4 (1.3-5.2) to 9.5 (5.8-12.7) mm, p < 0.001; and a reduction in the median peak pressure gradient across the coarctation from 35 (20-49) to 9 (0-15) mmHg, p < 0.001. Median stent recoil was 7.9 (0-20)%. There was one case of access related complication that resolved without sequelae. Follow-up was a median of 15 (3.0-57.2) months. CT angiogram performed at a median time of 3.3 (2.6-10.2) months post procedure showed no aortic wall injury and preserved stent integrity in all cases. Two children underwent re-intervention for stent dilation and further stent implantation due to in-stent stenosis and somatic growth after 3 years. Six of fourteen children remained on a single antihypertensive agent post-intervention at last follow-up. Implantation of the dilatable Valeo stent is a feasible treatment strategy in native or recurrent coarctation in small children, accepting that additional stent implantation may be necessary with somatic growth. Further study is required to determine longer-term stent efficacy and clinical outcome.

"Intraoperative hybrid stenting of recurrent coarctation and arch hypoplasia with large stents in patients with univentricular hearts"

BACKGROUND

Obstruction of the reconstructed aortic arch, tubular hypoplasia and recurrent coarctation (RC) is an important risk factor in univentricular physiology. For the past two years we have adopted the concept of intraoperative hybrid stenting of RC and arch hypoplasia with large stents in patients with univentricular hearts as standard care procedure.

METHOD/RESULT

Retrospective analysis of the anatomy and procedural outcome of 14 patients was scheduled for intraoperative stenting of the aortic arch (12 during surgery for BCPS, 2 during Fontan completion). The median age was 5.3 months, weight 5.5 kg, height 62 cm. Five patients had tubular hypoplasia and 9 patients had distal stenosis of the aortic arch. Nine patients had a previous balloon dilatation. The mean diameter of the distal arch was 11.0mm, at the coarctation 5.1mm, at the level of the diaphragm 8.2mm (CoA-index 0.62). Intraoperative stenting was performed in 13/14 patients. Stents were implanted with a mean balloon diameter of 10.8mm (SD 3.4mm). The achieved final mean diameter was 9.8mm (mean, SD 2.8mm) with an oversized Coa-index of 1.2. There was no re-coarctation at a mean follow-up of 7.3 months (range 3 to 24), the maximum flow velocity of 2m/s across the stented lesion assessed by ECHO.

CONCLUSION

This hybrid approach is an easy and safe concept to manage recurrent aortic arch hypoplasia and stenosis. The use of large stents allows redilatation to adult size diameters later on.