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Mechanical analysis of ovine and pediatric pulmonary artery for heart valve stent design


Cabrera, M S; Oomens, C W J; Bouten, C V C; Bogers, A J J C; Hoerstrup, S P; Baaijens, F P T (2013). Mechanical analysis of ovine and pediatric pulmonary artery for heart valve stent design. Journal of Biomechanics, 46(12):2075-2081.

Abstract

Transcatheter heart valve replacement is an attractive and promising technique for congenital as well as acquired heart valve disease. In this procedure, the replacement valve is mounted in a stent that is expanded at the aimed valve position and fixated by clamping. However, for this technique to be appropriate for pediatric patients, the material properties of the host tissue need to be determined to design stents that can be optimized for this particular application. In this study we performed equibiaxial tensile tests on four adult ovine pulmonary artery walls and compared the outcomes with one pediatric pulmonary artery. Results show that the pediatric pulmonary artery was significantly thinner (1.06±0.36mm (mean±SD)) than ovine tissue (2.85±0.40mm), considerably stiffer for strain values that exceed the physiological conditions (beyond 50% strain in the circumferential and 60% in the longitudinal direction), more anisotropic (with a significant difference in stiffness between the longitudinal and circumferential directions beyond 60% strain) and presented stronger non-linear stress-strain behavior at equivalent strains (beyond 26% strain) compared to ovine tissue. These discrepancies suggest that stents validated and optimized using the ovine pre-clinical model might not perform satisfactorily in pediatric patients. The material parameters derived from this study may be used to develop stent designs for both applications using computational models.

Abstract

Transcatheter heart valve replacement is an attractive and promising technique for congenital as well as acquired heart valve disease. In this procedure, the replacement valve is mounted in a stent that is expanded at the aimed valve position and fixated by clamping. However, for this technique to be appropriate for pediatric patients, the material properties of the host tissue need to be determined to design stents that can be optimized for this particular application. In this study we performed equibiaxial tensile tests on four adult ovine pulmonary artery walls and compared the outcomes with one pediatric pulmonary artery. Results show that the pediatric pulmonary artery was significantly thinner (1.06±0.36mm (mean±SD)) than ovine tissue (2.85±0.40mm), considerably stiffer for strain values that exceed the physiological conditions (beyond 50% strain in the circumferential and 60% in the longitudinal direction), more anisotropic (with a significant difference in stiffness between the longitudinal and circumferential directions beyond 60% strain) and presented stronger non-linear stress-strain behavior at equivalent strains (beyond 26% strain) compared to ovine tissue. These discrepancies suggest that stents validated and optimized using the ovine pre-clinical model might not perform satisfactorily in pediatric patients. The material parameters derived from this study may be used to develop stent designs for both applications using computational models.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Division of Surgical Research
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2013
Deposited On:12 Sep 2013 15:15
Last Modified:17 Feb 2017 09:55
Publisher:Elsevier
ISSN:0021-9290
Publisher DOI:https://doi.org/10.1016/j.jbiomech.2013.04.020
PubMed ID:23849135

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