Mechanical behavior of vessel wall: a comparative study of aorta, vena cava, and carotid artery.

We have used incremental stress-strain curves to study the mechanical behavior of porcine aorta, carotid artery, and vena cava. Elastic and viscous stress-strain curves are composed of low and high strain regions that are approximately linear. Analysis of the low strain behavior is consistent with previous studies that suggest that the behavior is dominated by the behavior of elastic fibers, and that the collagen and elastic fibers are in parallel networks. At high strain, the behavior is different than that of skin where it is dominated by the behavior of the collagen fibers. The high strain behavior is consistent with a series arrangement of the collagen and smooth muscle; however, the arrangement of smooth muscle and collagen may be different in aorta than in the other vessels studied. It is concluded that the mechanical behavior of the vessel wall differs from the behavior of other extracellular matrices that do not contain smooth muscle. Our results indicate that at least some of the collagen fibrils in the media are in series with smooth muscle cells and this collagen-smooth muscle network is in parallel with parallel networks of collagen and elastic tissue in aorta, carotid artery, and vena cava. It is concluded that the series arrangement of collagen and smooth muscle may be important in mechanochemical transduction in vessel walls and that the exact quantity and arrangement of these components may differ in different vessels.