Transmural pressure-area relation for veins and arteries

Experiments on isolated dog carotid arteries and jugular veins are performed to examine the effects of altered transmural pressure on the cross-sectional area of the blood vessel lumen. The data serves to provide a foundation describing the collapse of both arteries and veins for both positive and negative transmural pressures. In all normal and paralyzed vessels studied, change from a circular shape to collapsed occurred in the positive transmural pressure range, while in an elastic tube of similar geometry it occurred in the negative range. Over normal physiological pressure range, the veins showed a maximum normalized compliance (dA/dP)A₀ nearly ten times greater than that in the arteries. At higher transmural pressures the veins were considerably stiffer than the arteries. The veins assumed a circular shape at lower positive transmural pressures than did the arteries. The lumen normalized cross-sectional area from a paralyzed vessel showed a decrease for a given transmural pressure when compared with that of a normal vessel at the same transmural pressure