Annals of Biomedical Engineering

, Volume 30, Issue 5, pp 624–635 | Cite as

Mechanical Properties of Dilated Human Ascending Aorta

  • Ruth J. Okamoto
  • Jessica E. Wagenseil
  • William R. DeLong
  • Sara J. Peterson
  • Nicholas T. Kouchoukos
  • Thoralf M. SundtIII


Dilation of the ascending aorta, associated with Marfan Syndrome, bicuspid aortic valve, or advanced age, may lead to aortic dissection and rupture. Mathematical models can be used to assess the relative importance of increased wall stresses and decreased strength in these mechanical failures. To obtain needed inputs for such models, mechanical properties of dilated human ascending aorta were measured in vitro. Specimens for opening angle, biaxial elastic, and uniaxial circumferential strength tests were cut from excised tissue obtained from 54 patients (age 18–81 years) undergoing elective aortic graft replacement surgery. Opening angle was significantly greater in patients older than 50 years (262°±76°, n=21) compared to younger patients (202°±70°, n=13 All biaxial elastic specimens n=40 exhibited nonlinear stress-strain behavior. Rapid increases in circumferential and axial stresses occurred at lower strains in the older patient group than in the younger. Mean strength was significantly lower in older patients (1.35±0.37 MPa, n=14) than younger (2.04 ± 0.46 MPa, n=11, age <50 years). These changes in mechanical properties suggest that age may influence the risk of aortic dissection or rupture of dilated ascending aorta. © 2002 Biomedical Engineering Society.

PAC2002: 8719Rr, 8719Hh

Vascular mechanics Elasticity Strength Aortic disease 


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  1. 1.
    Badreck-Amoudi, A., C. K. Patel, T. P. Kane, and S. E. Greenwald. The effect of age on residual strain in the rat aorta. ASME J. Biomech. Eng. 118:440–444, 1996.Google Scholar
  2. 2.
    Chuong, C. J., and Y. C. Fung. On residual stresses in arteries. ASME J. Biomech. Eng. 108:189–192, 1986.Google Scholar
  3. 3.
    Chuong, C. J., and Y. C. Fung. Three-dimensional stress distribution in arteries. ASME J. Biomech. Eng. 105:268–274, 1983.Google Scholar
  4. 4.
    Debes, J. C., and Y. C. Fung. Biaxial mechanics of excised canine pulmonary arteries. Am. J. Physiol. 269:H433-H442, 1995.Google Scholar
  5. 5.
    Deng, S. X., J. Tomioka, J. C. Debes, and Y. C. Fung. New experiments on shear modulus of elasticity of arteries. Am. J. Physiol. 266:H1-H10, 1994.Google Scholar
  6. 6.
    Ferraresi, C., A. M. Bertetto, L. Mazza, D. Maffiodo, and W. Franco. One-dimensional experimental mechanical characterization of porcine aortic root wall. Med. Biol. Eng. Comput. 37:202–207, 1999.Google Scholar
  7. 7.
    Fung, Y. C. Biomechanics: Mechanical Properties of Living Tissues, 2nd ed. New York: Springer, 1993, p. 568.Google Scholar
  8. 8.
    Fung, Y. C. What are the residual stresses doing in our arteries? Ann. Biomed. Eng. 19:237–249, 1991.Google Scholar
  9. 9.
    Hahn, R. T., M. J. Roman, A. H. Mogtader, and R. B. Devereux. Association of aortic dilation with regurgitant, stenotic and functionally normal bicuspid aortic valves. J. Am. Coll. Cardiol. 19:283–288, 1992.Google Scholar
  10. 10.
    Han, H. C., and Y. C. Fung. Species dependence of the zero-stress state of aorta: Pig versus rat. ASME J. Biomech. Eng. 113:446–451, 1991.Google Scholar
  11. 11.
    Hirata, K., F. Triposkiadis, E. Sparks, J. Bowen, C. F. Wooley, and H. Boudoulas. The Marfan syndrome: Abnormal aortic elastic properties. J. Am. Coll. Cardiol. 18:57–63, 1991.Google Scholar
  12. 12.
    Humphrey, J. D. An evaluation of pseudoelastic descriptors used in arterial mechanics. ASME J. Biomech. Eng. 121:259–262, 1999.Google Scholar
  13. 13.
    Humphrey, J. D. Mechanics of the arterial wall: Review and directions. Crit. Rev. Biomed. Eng. 23:1–162, 1995.Google Scholar
  14. 14.
    Humphrey, J. D., D. L. Vawter, and R. P. Vito. Quantification of strains in biaxially tested soft tissues. J. Biomech. 20:59–65, 1987.Google Scholar
  15. 15.
    Jeremy, R. W., H. Huang, J. Hwa, H. McCarron, C. F. Hughes, and J. G. Richards. Relation between age, arterial distensibility, and aortic dilatation in the Marfan syndrome. Am. J. Cardiol. 74:369–373, 1994.Google Scholar
  16. 16.
    Kang, T., J. Resar, and J. D. Humphrey. Heat-induced changes in the mechanical behavior of passive coronary arteries. ASME J. Biomech. Eng. 117:86–93, 1995.Google Scholar
  17. 17.
    Langewouters, G. J., K. H. Wesseling, and W. J. Goedhard. The static elastic properties of 45 human thoracic and 20 abdominal aortas in vitro and the parameters of a new model. J. Biomech. 17:425–435, 1984.Google Scholar
  18. 18.
    Learoyd, B. M., and M. G. Taylor. Alterations with age in the viscoelastic properties of human arterial walls. Circ. Res. 18:278–292, 1966.Google Scholar
  19. 19.
    Liu, S. Q., and Y. C. Fung. Zero-stress states of arteries. ASME J. Biomech. Eng. 110:82–84, 1988.Google Scholar
  20. 20.
    May-Newman, K., and F. C. P. Yin. Biaxial mechanical behavior of excised porcine mitral valve leaflets. Am. J. Physiol. 269:H1319-H1327, 1995.Google Scholar
  21. 21.
    Mohan, D., and J. W. Melvin. Failure properties of passive human aortic tissue. I-uniaxial tension tests. J. Biomech. 1:887–902, 1982.Google Scholar
  22. 22.
    Nielsen, P. M. F., P. J. Hunter, and B. H. Smaill. Biaxial testing of membrane biomaterials: Testing equipment and procedures. ASME J. Biomech. Eng. 113:295–300, 1991.Google Scholar
  23. 23.
    Oxlund, H., L. M. Rasmussen, T. T. Andreassen, and L. Heickendorff. Increased aortic stiffness in patients with type1 (insulin-dependent) diabetes mellitus. Diabetologia 32:748–752, 1989.Google Scholar
  24. 24.
    24 Perejda, A. J., P. A. Abraham, W. H. Carnes, W. F. Coulson, and J. Uitto. Marfan's syndrome: Structural, biochemical, and mechanical studies of the aortic media. J. Lab. Clin. Med. 106:376–383, 1985.Google Scholar
  25. 25.
    Peterson, S. J., and R. J. Okamoto. Effect of residual stress and heterogeneity on circumferential stress in the arterial wall. ASME J. Biomech. Eng. 122:454–456, 2000.Google Scholar
  26. 26.
    Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery. Numerical Recipes in Fortran: The Art of Scientific Computing, 2nd ed. New York: Cambridge University Press, 1992.Google Scholar
  27. 27.
    Raghavan, M. L., M. W. Webster, and D. A. Vorp. Ex vivo biomechanical behavior of abdominal aortic aneurysm: Assessment using a new mathematical model. Ann. Biomed. Eng. 24:573–582, 1996.Google Scholar
  28. 28.
    Rhodin, J. Architecture of the vessel wall, in Handbook of Physiology, Section 2, The Cardiovascular System, Vol. 2, Vascular Smooth Muscle, edited by R. M. Berne. American Physiological Society, 1979, pp. 1–31.Google Scholar
  29. 29.
    Robicsek, F., and M. J. Thubrikar.Hemodynamic considerations regarding the mechanism and prevention of aortic dissection. Ann. Thoracic Surgery 58:1247–1253, 1994.Google Scholar
  30. 30.
    Romanes, G. J. Cunningham's Textbook of Anatomy, 11th ed. London: Oxford University Press, 1972.Google Scholar
  31. 31.
    Saini, A., C. Berry, and S. Greenwald. Effect of age and sex on residual stress in the aorta. J. Vasc. Res. 32:398–405, 1995.Google Scholar
  32. 32.
    Stergiopulos, N., A. Pannatier, A. Rachev, and J. Meister. Elastic response of the arterial wall under physiologic and nonphysiologic initial stress distribution: applicability of the strain energy function. 1994 ASME Adv. Bioeng. 28:67–68, 1994.Google Scholar
  33. 33.
    Svensson, L. G., and E. S. Crawford. Cardiovascular and Vascular Disease of the Aorta. Philadelphia, PA: W. B. Saunders Company, 1997, p. 472.Google Scholar
  34. 34.
    Toda, N., M. Hojo, and K. Sakae. Modification by temperature of the response of isolated aorta to stimulatory agents and transmural stimulation. Blood Vessels 13:210–221, 1976.Google Scholar
  35. 35.
    Vaishnav, R. N., and J. Vossoughi. Residual stress and strain in aortic segments. J. Biomech. 20:235–239, 1987.Google Scholar
  36. 36.
    von Maltzahn, W. W., R. G. Warriyar, and W. F. Keitzer. Experimental measurements of elastic properties of media and adventitia of bovine carotid arteries. J. Biomech. 17:839–847, 1984.Google Scholar
  37. 37.
    Xie, J. P.,J. Zhou, and Y. C. Fung. Bending of blood vessel wall: Stress-strain laws of the intima-media and adventitial layers. ASME J. Biomech. Eng. 117:136–145, 1995.Google Scholar
  38. 38.
    Zhou, J., and Y. C. Fung. The degree of nonlinearity and anisotropy of blood vessel elasticity. Proc. Natl. Acad. Sci. U.S.A. 94:14255–14260, 1997.Google Scholar

Copyright information

© Biomedical Engineering Society 2002

Authors and Affiliations

  • Ruth J. Okamoto
    • 1
    • 2
  • Jessica E. Wagenseil
    • 2
  • William R. DeLong
    • 1
  • Sara J. Peterson
    • 2
  • Nicholas T. Kouchoukos
    • 3
  • Thoralf M. SundtIII
    • 4
  1. 1.Department of Mechanical EngineeringMissouri Baptist Medical CenterSt. Louis
  2. 2.Department of Biomedical EngineeringMissouri Baptist Medical CenterSt. Louis
  3. 3.Missouri Baptist Medical CenterSt. Louis
  4. 4.Division of Cardiothoracic SurgeryWashington UniversitySt. Louis

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