Flow-Induced Changes in Dimensions and Mechanical Properties of Rabbit Common Carotid Arteries ∗

Flow-induced changes in dimensions and mechanical properties of blood vessel wall were studied in the rabbit left common carotid arteries connected directly to the left external jugular vein via an arteriovenous fistula (AVF) to increase its blood flow by >10-fold for 4 weeks. Contralateral artery was used as control. We found significant increase not only in diameter, but also in thickness and length of unloaded artery exposed to increased flow, indicating the increase in wall volume. The increase in diameter and thickness but not in longitudinal length correlated significantly with the volumetric increase of the wall. Pressure-imposed test showed that the wall became less distensible in response to flow increase. Fluid shear stress estimated for physiological condition was significantly higher in AVF side than control, indicating that 10-fold increase in flow was not compensated in 4 weeks. Circumferential strain in a physiological pressure range was significantly lower in AVF side, while hoop stress was similar in both sides. These results may indicate that circumferential stress but not strain is maintained constant, and longitudinal change is not regulated in flow-imposed arteries.