Mechanics of the Human Common Carotid Artery in Vivo

The relationships between lateral intravascular pressure, vessel radius, and vessel length were evaluated in the common carotid artery in vivo in thirteen patients during treatment by surgery. Strain was measured in the wall of the carotid artery by means of an electrical caliper sutured to the vessel wall. Lateral intravascular pressure was measured directly with either an 18-gauge needle or a short polyethylene catheter connected to a Statham, P23Db, strain gauge. The results indicate that circumferential and longitudinal strains in the common carotid artery were both small. The mean systolic change in cross-sectional area was 2.10% (±SD 1.08) of the end diastolic area. In three patients a negative circumferential strain was produced by making the cross section of the vessel elliptical. During systole, longitudinal strain increased in four patients and decreased in six patients. The average change in vessel segment length during systole was approximately 1.0% of the end diastolic length.