Determining the critical buckling pressure of blood vessels through modeling and in vitro experiments

dc.contributor.advisorHan, Hai-Chao
dc.contributor.authorLee, Avione Y.
dc.contributor.committeeMemberAppleford, Mark
dc.contributor.committeeMemberDong, Xuanliang
dc.contributor.committeeMemberGriffin, Kenneth
dc.contributor.committeeMemberLindsey, Merry
dc.contributor.committeeMemberSprague, Eugene
dc.contributor.committeeMemberYang, Mijia
dc.date.accessioned2024-02-12T14:53:27Z
dc.date.available2024-02-12T14:53:27Z
dc.date.issued2011
dc.descriptionThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.
dc.description.abstractIntroduction. Tortuous arteries are often associated with aging, hypertension, atherosclerosis, and degenerative vascular diseases, but the mechanisms are poorly understood. Our recent theoretical analysis and experimental observation suggested that mechanical instability (buckling) may lead to tortuous blood vessels. The theoretical analysis, however, needs careful validation with experimental results. In addition, the mechanism behind the propensity of tortuosity formation in elastin degraded arteries or arteries with geometric variations have not been addressed. The objectives of this study were to validate the critical buckling equation for blood vessels and to study the effect of elastin degradation and geometric variations on the mechanical stability of arteries. Methods. The mechanical properties and critical buckling pressures (CBP), at which arteries become unstable and deform into tortuous shapes, were previously determined for a group of eight veins and five arteries (normal groups) using pressurized inflation and buckling tests. Another group of six porcine arteries were treated with elastase (elastase group, 8 U/ml) and the mechanical stiffness and CBP's were obtained before and after treatment. The artery behavior was determined by finding the material constants of the Fung energy equation and the CPB was predicted using the MC's and the critical buckling equation. The material constants were also used in finding the CBP of arteries with geometric variations using finite element analysis. Results. The experimental CPB of the eight veins tested was 1.95 +/- 0.67 kPa; while the model predicted CPB was 1.91+/-0.69 kPa (at an axial stretch ratio of lambda=1.5). The CPB of the normal artery group was 17.10+/-5.11kPa, while model predicted critical pressures was 17.86+/-5.21kPa (lambda=1.5). The elastase group had a significant decrease in the CPB (p<0.01) post treatment. The CBP's of the 6 elastase treated arteries was 19.86 +/- 5.31 and 9.13 +/- 3.61 kPa before and after treatment, respectively (lambda=1.5); while the model predicted CBP's was 16.95 +/- 10.45 and 8.43 +/- 3.58 kPa before and after treatment, respectively (lambda=1.5). All arteries with geometric variations also had a decrease in their CPB. Conclusion. Artery buckling under lumen pressure can be predicted by a critical buckling equation. Elastin degradation and geometric variations reduce the critical buckling pressure which may lead to tortuous vessels. These results shed light on the buckling behavior of arteries and veins.
dc.description.departmentBiomedical Engineering
dc.format.extent225 pages
dc.format.mimetypeapplication/pdf
dc.identifier.isbn9781124876955
dc.identifier.urihttps://hdl.handle.net/20.500.12588/4372
dc.languageen
dc.subjectaneurysm
dc.subjectartery
dc.subjectbuckling
dc.subjectelastin
dc.subjecttortuosity
dc.subjectvein
dc.subject.classificationBiomedical engineering
dc.subject.classificationBiomechanics
dc.titleDetermining the critical buckling pressure of blood vessels through modeling and in vitro experiments
dc.typeThesis
dc.type.dcmiText
dcterms.accessRightspq_closed
thesis.degree.departmentBiomedical Engineering
thesis.degree.grantorUniversity of Texas at San Antonio
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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