Does hemodynamic adaptation take place in the vein grafted into an artery?

Emil Monos, József Csengődy

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Four to five centimeter long autogenous femoral vein segments were grafted "end-to-end" into the femoral artery of 9 anaesthetized dogs. Three to seven months after surgery the biomechanical properties of the 1.5-2 cm long central part of the grafted vein segment (G) was studied in vitro. Large-deformation mechanical test was applied. Intraluminal pressure was changed in 0-250 mm Hg range at a constant length and the values of external diameter and axial extending force were recorded as the functions of intraluminal pressure. The following parameters were used for characterizing the mechanical properties of the vessel wall: tangential (S θ{symbol} ), radial (S R ) and axial stresses (S Z ), relative deformations, strain-energy density (SED), radius to wall thickness ratio (a/h), incremental elastic modulus (E), distensibility (D) and characteristic impedance (Z 0 ). The data obtained with G veins were compared with those of 10 normal femoral veins (N). It was found that ratios of G/N for S θ{symbol} , S R , S Z , SED, a/h and E values were about 0.2 in the whole intraluminal pressure range studied. There were no significant differences in the values of D and Z 0 between the two groups. Norepinephrine in high dose (5 μg/ml) induced moderate smooth muscle contraction in the G veins only; the geometric response (maximum reduction of internal radius) was 5-7%, which occurred in the 0-10 mm Hg intraluminal pressure range. There was no contraction at all above 80 mm Hg intraluminal pressure level. The smooth muscle of N veins did not react to norepinephrine during large deformation test. The present results show that the "arterialization" tendency of S and E values in the G veins is compensated by the increase in wall thickness, as far as distensibility is concerned. Both N and G veins with relaxed smooth muscle behaved like rigid tubes compared to arteries in the arterial pressure range in vitro, that means that no hemodynamic adaptation took place. The slight smooth muscle activity found is not sufficient enough to modify biomechanical properties of the G veins at arterial pressure load significantly. We assume that the reduction of S and E reflects a tissue mechanism, which controls the long term hemodynamic adaptation of the vessel wall.

Original languageEnglish
Pages (from-to)177-182
Number of pages6
JournalPflügers Archiv European Journal of Physiology
Volume384
Issue number2
DOIs
Publication statusPublished - Mar 1980

Keywords

  • Biomechanics of veins
  • Distensibility of venous grafts
  • Elasticity of veins
  • Vascular impedance
  • Venous grafts

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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