|Abstract:|| Knowledge of blood flow mechanics is a critical issue (1) for an in depth understanding of the relationships between hemodynamic factors and arterial homeostasis and (2) for the identification of those flow features that lead to changes in the function and health of vessels. While from one side there is clear evidence that regions of disrupted flow are correlated to, e.g., the localization of atherosclerosis, the development of
neurysms and non-physiological transport of species, on the opposite cause-effect links still do not emerge clearly. To allow for a more effective and valuable understanding of blood flow structures and mechanisms in complex four-dimensional cardiovascular flows, in recent years a large number of hemodynamic parameters have surfaced in the literature, enabling the understanding of arterial hemodynamics and of the role of streaming blood in the development of pathological events. Here, a survey of recently proposed methods to characterize in! travascular fluid structures in arteries, in particular helical flow, is presented and their relationship with (1) widely adopted disturbed shear indicators as well as (2) emerging indicators of the relevance of wall shear stress multidirectionality in the distribution of vascular lesions, are discussed together with open questions on their clinical utility.