Damage and failure in the carotid artery: a mechanistic approach

Blunt carotid artery injury (BCAI), resulting primarily from automobile accidents, is a major contributor to the high mortality and morbidity rates associated with carotid artery dissection. More work is needed to characterize carotid artery injury mechanisms, quantify stages of damage, and elucidate failure modalities as a result of this type of injury. The present study examines the structure and mechanics of the carotid artery in the circumferential and axial directions by employing uniaxial tensile testing, high speed videography, interruption testing, scanning electron microscopy (SEM), histological analysis, real-time environmental SEM assessment, and atomic force microscopy (AFM). Results are as follows: (i) the carotid artery exhibits anisotropic, viscoelastic behavior; (ii) intimal failure precedes ultimate tissue failure, and the layers in order of increasing strength are intima, adventitia, and media; (iii) tissue damage accumulates as strain level increases, and failure occurs as a result of void nucleation, void growth, and void coalescence.