Effect of residual stress and heterogeneity on circumferential stress in the arterial wall

Quantifying the stress distribution through the arterial wall is essential to studies of arterial growth and disease. Previous studies have shown that both residual stress, as measured by opening angle, and differing material properties for the media-intima and the adventitial layers affect the tran smural circumferential stress (sigma (theta)) distribution. Because a lack of comprehensive data on a single species and artery has led to combination s from multiple sources, this study determined the sensitivity of sigma (th eta) to published variations in both opening angle and layer thickness data . We fit material properties to previously published experimental data for pressure-diameter relations and opening angles of rabbit carotid artery, an d predicted sigma (theta) through the arterial wall at physiologic conditio ns. Using a one-layer model, the ratio of sigma (theta) at the internal wal l to the mean sigma (theta) decreased from 2.34 to 0.98 as the opening angl e increased from 60 to 130 deg. In a two-layer model using a 95 deg opening angle, mean sigma (theta) in the adventitia increased (112 percent for 25 percent adventitia) and mean sigma (theta) in the media decreased (47 perce nt for 25 percent adventitia). These results suggest that both residual str ess and wall layers have important effects on transmural stress distributio n. Thus, experimental measurements of loading curves, opening angles, and w all composition from the same species and artery are needed to accurately p redict the transmural stress distribution in the arterial wall. [S0148-0731 (00)02204-4].