Measuring and Modeling the Viscoelastic Properties of the Human Saphenous Vein Using the Pressure–Diameter Test

Abstract

Coronary artery bypass graft surgery is a customary therapy for vascular-related diseases, with many thousands of such a surgical modality reported annually. In this surgery, the saphenous vein, internal mammary artery, or radial artery is grafted in order to replace the coronary arteries. Using a device designed in our own laboratory, we primarily sought to find a suitable model representing the mechanical behavior of the human saphenous vein wall and then to assess its mechanical properties. The most important feature of this device is its ability to simulate the physiological conditions that exist inside the human body. We obtained 2 samples the saphenous opening and the medial epicondyle in patients with hypertension. After performing measurements at frequencies near to the heart beat frequency and finding the loss and storage moduli for each frequency, we found that—in the scanned frequency range—the Kelvin model was the best approach to evaluating the viscoelastic behavior of the vessels. Our findings also indicated that the elasticity and damping coefficients could be deemed equal along the length of the saphenous vein. Accordingly, we would advise that heart surgeons not consider the changes in the mechanical properties along the length of the saphenous vein at the time of transplantation. (Iranian Heart Journal 2016; 17(3):27-35