Retrograde embolism and atherosclerosis development in the human thoracic aorta: are the fluid dynamics explanations valid?

Abstract

The mechanisms of atherosclerosis development in the thoracic aorta is miscellaneous and still only partially understood. The marked variability of the sites of deposition of atherosclerotic plaques in the aorta could not be clarified based solely on the risk-factors theory of atherosclerosis. The sites of deposition of atherosclerotic plaques are considered to be affected by blood-flow patterns that cause areas of altered shear stress on the aortic wall. Close relations between protruding aortic plaques (PAP), stroke and peripheral emboli were established. The analysis of PAP distribution and motion to characterize atherogenesis in the human thoracic aorta and the pathogeneses of embolic events was performed. We concluded that protruding aortic plaques and markers of relative aortic flow instability (occurrences of vortices) are predominantly noticed in the human arch and in the descending aorta, whereas the ascending aorta showed lesser prevalence of atheromatosis. Reversal and rotational blood-flow in the thoracic aorta most likely exist in all patients with systemic emboli and mobile protruding aortic atheromas. Therefore, retrograde cerebral embolism from distal aortic plaques is conceivable.