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Design optimization of coronary stent based on finite element models.

Li H, Qiu T, Zhu B, Wu J, Wang X - ScientificWorldJournal (2013)

Bottom Line: An infilling sampling criterion named expected improvement (EI) is used to balance local and global searches in the optimization iteration.Thrombosis models of three typical shapes are built to test the effectiveness of optimization results.Numerical results show that two finite element models dilated by pressure applied inside the balloon are available, one of which with the artery and plaque can give an optimal stent with better expansion behavior, while the artery and plaque unincluded model is more efficient and takes a smaller amount of computation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian 116024, China.

ABSTRACT
This paper presents an effective optimization method using the Kriging surrogate model combing with modified rectangular grid sampling to reduce the stent dogboning effect in the expansion process. An infilling sampling criterion named expected improvement (EI) is used to balance local and global searches in the optimization iteration. Four commonly used finite element models of stent dilation were used to investigate stent dogboning rate. Thrombosis models of three typical shapes are built to test the effectiveness of optimization results. Numerical results show that two finite element models dilated by pressure applied inside the balloon are available, one of which with the artery and plaque can give an optimal stent with better expansion behavior, while the artery and plaque unincluded model is more efficient and takes a smaller amount of computation.

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Related in: MedlinePlus

FEM models. (a) LRD model: loaded by a radial displacement to expand the diameters of stent from 2.54 mm to 4.54 mm. (b) LPV model: loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm. (c) LPC model: loaded by a constant pressure. (d) SMPV model: without artery and plaque, loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm.
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fig2: FEM models. (a) LRD model: loaded by a radial displacement to expand the diameters of stent from 2.54 mm to 4.54 mm. (b) LPV model: loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm. (c) LPC model: loaded by a constant pressure. (d) SMPV model: without artery and plaque, loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm.

Mentions: The four FEA models are here constructed. LRD model (shown in Figure 2(a)) is loaded by a radial displacement applied on the inner surface of balloon to expand the diameters of stent from 2.54 mm to 4.54 mm. This is to allow the stenotic segment to be opened corresponding to the health artery (diameter 4.54 mm in this study). It is discretized by 11815 elements and 10180 nodes, in which the plaque, artery, stent, and balloon consist of 500 solid elements, 330 solid elements, 5103 solid elements, and 600 shell elements, respectively. The contact pairs of balloon/stent, plaque/stent, and balloon/plaque consist of 5282 contact elements. LPV model (shown in Figure 2(b)) is the same as LRD model except the loading method. This model is loaded by a time-related pressure (shown in Figure 3). It should be noted that the pressures are varied with different stent geometries. The binary-search method was used to find the pressures used to dilate the proximal region of the stents (see Figure 1) to the nominal diameter (4.54 mm in this study) after unloading. This was done to allow the stenotic segment to be opened in agreement with a health artery (diameter 4.54 mm in this study) after stent dilation. LPC model (shown in Figure 2(c)) is similar to LPV model except the constant pressure. The last one is SMPV model which has the same loading method as LPV model, but artery and plaque were not considered (shown in Figure 2(d)). It is discretized by 8004 elements and 8444 nodes, in which the stent and balloon consist of 5103 solid elements and 600 shell elements, respectively. Only one contact pair of balloon/stent consists of 2301 contact elements.


Design optimization of coronary stent based on finite element models.

Li H, Qiu T, Zhu B, Wu J, Wang X - ScientificWorldJournal (2013)

FEM models. (a) LRD model: loaded by a radial displacement to expand the diameters of stent from 2.54 mm to 4.54 mm. (b) LPV model: loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm. (c) LPC model: loaded by a constant pressure. (d) SMPV model: without artery and plaque, loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814053&req=5

fig2: FEM models. (a) LRD model: loaded by a radial displacement to expand the diameters of stent from 2.54 mm to 4.54 mm. (b) LPV model: loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm. (c) LPC model: loaded by a constant pressure. (d) SMPV model: without artery and plaque, loaded by a pressure to expand the diameters of stent from 2.54 mm to 4.54 mm.
Mentions: The four FEA models are here constructed. LRD model (shown in Figure 2(a)) is loaded by a radial displacement applied on the inner surface of balloon to expand the diameters of stent from 2.54 mm to 4.54 mm. This is to allow the stenotic segment to be opened corresponding to the health artery (diameter 4.54 mm in this study). It is discretized by 11815 elements and 10180 nodes, in which the plaque, artery, stent, and balloon consist of 500 solid elements, 330 solid elements, 5103 solid elements, and 600 shell elements, respectively. The contact pairs of balloon/stent, plaque/stent, and balloon/plaque consist of 5282 contact elements. LPV model (shown in Figure 2(b)) is the same as LRD model except the loading method. This model is loaded by a time-related pressure (shown in Figure 3). It should be noted that the pressures are varied with different stent geometries. The binary-search method was used to find the pressures used to dilate the proximal region of the stents (see Figure 1) to the nominal diameter (4.54 mm in this study) after unloading. This was done to allow the stenotic segment to be opened in agreement with a health artery (diameter 4.54 mm in this study) after stent dilation. LPC model (shown in Figure 2(c)) is similar to LPV model except the constant pressure. The last one is SMPV model which has the same loading method as LPV model, but artery and plaque were not considered (shown in Figure 2(d)). It is discretized by 8004 elements and 8444 nodes, in which the stent and balloon consist of 5103 solid elements and 600 shell elements, respectively. Only one contact pair of balloon/stent consists of 2301 contact elements.

Bottom Line: An infilling sampling criterion named expected improvement (EI) is used to balance local and global searches in the optimization iteration.Thrombosis models of three typical shapes are built to test the effectiveness of optimization results.Numerical results show that two finite element models dilated by pressure applied inside the balloon are available, one of which with the artery and plaque can give an optimal stent with better expansion behavior, while the artery and plaque unincluded model is more efficient and takes a smaller amount of computation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian 116024, China.

ABSTRACT
This paper presents an effective optimization method using the Kriging surrogate model combing with modified rectangular grid sampling to reduce the stent dogboning effect in the expansion process. An infilling sampling criterion named expected improvement (EI) is used to balance local and global searches in the optimization iteration. Four commonly used finite element models of stent dilation were used to investigate stent dogboning rate. Thrombosis models of three typical shapes are built to test the effectiveness of optimization results. Numerical results show that two finite element models dilated by pressure applied inside the balloon are available, one of which with the artery and plaque can give an optimal stent with better expansion behavior, while the artery and plaque unincluded model is more efficient and takes a smaller amount of computation.

Show MeSH
Related in: MedlinePlus