LONGITUDINAL STRAIN OF CANINE AND PORCINE AORTAS

The in situ longitudinal strain of canine and porcine aortas was inves tigated. Marks of black water-resistant ink were placed on the aortas and the axial lengths between the marks were measured in situ and in v itro. When the aortas were cut, the retraction was measured and descri bed by the stretch ratio, which is defined as the length of a segment in situ divided by the length at no-load state. Results show that the stretch ratios of both porcine and canine aortas increase monotonicall y from 1.2 in the descending region to about 1.5 in abdominal region. Species differences are seen in the middle region. In both animals, th e stretch ratio is correlated to the cross-sectional area of the vesse l wall.