Stress analysis of vasoconstriction at arterial branch sites

The object of the research was to estimate wall stresses caused by vasoconstriction at arterial branches. The basic procedure was a combination of experimental strain measurement and analytical stress analysis. Segments of canine renal arteries were perfused and stimulated to constrict with dopamine hydrochloride and norepinephrine. Surface wall deformation was measured with a stereo-photographic technique. A plane stress finite element analysis was used to calculate wall stresses based on the experimentally derived deformations. The major result of the study was to demonstrate tensile stresses, and in some cases biaxial tension, in contracting vessels. Peak stresses in the apex of the acute angle of the branches were approximately three times unpenetrated hoop stress in the parent vessels. The results imply that constriction at a branch site may be capable of generating sufficient wall tension to tear arterial tissue, and that smooth muscle reactivity is important with respect to the etiology of cerebral aneurysms and the clinical management of acute branch site pathology.