DIFFERENCES IN MECHANICAL-PROPERTIES OF THE COMMON CAROTID-ARTERY ANDABDOMINAL-AORTA IN HEALTHY-MALES

Purpose: Vascular disease is differentiated throughout the vascular re gions, with central arteries more prone to dilation and with periphera l arteries more prone to occlusive disease. In this study we investiga ted the diameter and compliance in the common carotid artery and abdom inal aorta in healthy males at varying ages to assess potential differ ences in the aging process. Methods: An ultrasound phase-locked echo-t racking system was used to determine differences in diameter and pulsa tile diameter changes of the common carotid artery and abdominal aorta in 56 healthy Caucasian males ages 10 to 74 years. Pressure strain el astic modulus (Ep) and stiffness (beta) were calculated from diameter, pulsatile diameter change, and blood pressure obtained by the auscult atory method. Compliance was defined as the inverse of Ep and stiffnes s. Results: The diameter of both common carotid artery and abdominal a orta increases not only when a person is a child, but also when they a re between 25 and 70 years old. The dilation in adults seems to be mor e accentuated in the abdominal aorta (27%) than in the common carotid artery (17%). Ep and stiffness (beta) are higher in the common carotid artery when a person is 10 years of age (p < 0.01 and 0.05). However, during aging, Ep and stiffness (beta) increase to a higher extent in the aorta than in the common carotid artery, with a significantly high er Ep and stiffness (beta) in the aorta when a person is 45 years and older (45 years: p < 0.05 and p = NS; 60 years: p < 0.001 and p < 0.00 1; 70 years:p < 0.01 and p < 0.01). Conclusions: This investigation de monstrates regional differences in diameter change and compliance in t he common carotid artery and abdominal aorta and implies that the abdo minal aorta is more prone to degenerative changes than the common caro tid artery. This may be one etiologic factor for the regional differen ces in vascular disease.