Compressive stress-relaxation of human atherosclerotic plaque

Knowledge of the mechanical properties of human atherosclerotic plaque is f undamental to understanding atherosclerosis and its treatment. Data are sca nt, however, particularly with respect to the time-dependent nature of plaq ue behavior. Previous experiments in our lab showed that human plaques do n ot exhibit the traditional preconditioning behavior common to most soft tis sues. In particular, the behaviors of three classes of plaques differed fun damentally in response to multiple, successive, cyclic compression protocol s. In this report, we demonstrate that plaques exhibit different responses to successive relaxation tests in uniaxial compression. Not only is there s ignificant relaxation, but there are composition-dependent differences in t he general character of the relaxation responses. Such information on the t ime-dependent behavior is important for the design of clinical protocols su ch as stenting or angioplasty wherein the atherosclerotic vessel is subject ed to persistent or multiple short duration loadings. This study presents a step toward a better understanding of the biomechanical behavior of athero sclerotic plaques; however, the need for much more data remains. (C) 2001 J ohn Wiley & Sons, Inc.