Korean Circ J.  2013 Mar;43(3):207-211. 10.4070/kcj.2013.43.3.207.

An Adolescent Patient with Coarctation of Aorta Treated with Self-Expandable Nitinol Stent

• Shim WS
• Song JY
• Lee SY
• Baek JS
• Jang SI
• Kim SH
• Kim YM

• KMID: 2224969
• DOI: http://doi.org/10.4070/kcj.2013.43.3.207

Abstract

Transcatheter treatment of aortic coarctation, with balloon angioplasty or stent implantation, is now an acceptable alternative to surgical repair. However these procedures may result in complications, such as vascular wall injury and re-stenosis of the lesion. A nitinol self-expandable stent, when deployed at the coarctation site, produces low constant radial force, which may result in a gradual widening of the stenotic lesion leaving less tissue injury ('stretching rather than tearing'). For an adolescent with a native aortic coarctation, a self-expandable stent of 20 mm diameter was inserted at the discrete stenotic lesion of 5 mm diameter without previous balloon dilatation procedure. No further balloon dilatation was done immediately after the stent insertion. With the self-expandable stent only, the stenosis of the lesion was partially relieved immediately after the stent deployment. Over several months after the stent insertion, gradual further widening of the stent waist to an acceptable dimension was observed.

Keyword

Aortic coarctation; Stents

MeSH Terms

Adolescent
Angioplasty, Balloon
Aortic Coarctation
Constriction, Pathologic
Dilatation
Humans
Stents

Figure

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  Fig. 1 Echocardiographic examination before the insertion of the stent. A: Doppler study showed a maximum pressure gradient of 50 mm Hg across the aortic coarctation. B: M-mode echocardiagram showed relatively good systolic function of left ventricle without significant muscle wall hypertrophy.

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  Fig. 2 Images of the aortic coarctation at the time of stent insertion. A: multi-planar reconstructed CT images before the stent insertion showed discrete narrowing at the isthmic portion of aortic arch due to posterior shelf lesion measuring 4 mm in the narrowest dimension. B: aortic angiogram before the insertion of the stent showed discrete narrowing at the isthmus of the aortic arch measuring 5 mm in the narrowest dimension. C: aortic angiogram immediately after the insertion of the self-expandable nitinol stent showed the dimension of the stent waist 8 mm.

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  Fig. 3 Images of the aortic coarctation 3 months after the insertion of the self-expandable stent. A: multiplanar reconstructed CT images 3 months after the insertion of the self-expandable nitinol stent showed the dimension of the stent waist 11.5 mm. B and C: chest X-ray images 3 months after the insertion of the self-expandable nitinol stent showed the dimension of the stent waist 13 mm (B: anterior-posterior projection, C: lateral projection).

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  Fig. 4 Chest X-ray images 1 year after the insertion of the stent. Chest X ray images showed the dimension of the stent waist 14 mm. A: anterior-posterior projection. B: lateral projection.

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  Fig. 5 In the concentric compression and relaxation experiment of the self-expandable nitinol stent (S&G Biotech, Seongnam, Korea), the radial forces of the stent were measured at varying diameters of the stent. The 20 mm diameter self-expandable stent was tightened gradually by a ringed device to the diameter of 5 mm and thereafter loosened gradually to the diameter of 20 mm. As the stent is deformed to a smaller diameter, the stronger the radial force was observed. And as the diameter of the stent increased, the radial force exerted by the stent decreased rather steeply. The resistance force of the stent measured when the concentric compression force was loaded was greater than the expansion force of the stent measured when the concentric force was unloaded (Data from S&G Biotech, Seongnam, Korea).

Reference

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