Biomechanical properties of normal and fibrosclerotic human cerebral arteries.
Quasi-static passive mechanical properties of histologically fibrosclerotic and normal groups of human anterior cerebral arteries (ACA) and internal carotid arteries (ICA) were studied in vivo. Cylindrical arterial segments were subjected to slow, cyclic inflation by air in the range of 5-250 mm Hg intraluminal pressure at axial isometry. To characterize mechanical properties, incremental elastic modulus, incremental distensibility and strain energy density were computed from the continuously recorded pressure-external diameter curves. Compared to normal arteries, at identical intraluminal pressures, the elastic modulus of fibrosclerotic arteries was found to be 34-45% lower in ACA and 40-56% lower in ICA, and the radius to wall thickness ratio was 25-30% smaller in ACA and 37-38% smaller in ICA. Distensibility of fibrosclerotic arteries was not smaller than that of the normal vessels. There were no significant differences in internal radius and in strain energy density between the fibrosclerotic and normal groups. Results of mathematical modelling suggests that the observed decrease in the elastic modulus of fibrosclerotic arteries was accompanied by different types of structural reorganization in the case of ACA and ICA. It is supposed that changes in mechanical properties of the passive wall elements have a compensatory character to restore some hemodynamically important properties of fibrosclerotic arteries, namely tangential stress, incremental distensibility or characteristic impedance.
D001161:Arteriosclerosis / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries / Q000503:physiopathology; D002536:Cerebral Arteries / Q000503:physiopathology*; D004071:Digitalis Glycosides / Q000494:pharmacology; D006801:Humans
D004071:Digitalis Glycosides