Hemodynamic principles of arterial cannulation: Orientation, wall shear stress, turbulence, plaque destabilization, and cerebral microembolization.

BackgroundArterial cannulation during cardiopulmonary bypass (CPB) significantly alters native aortic hemodynamics by generating a high-velocity jet that interacts with the ascending aorta and aortic arch geometry. These flow disturbances may influence wall shear stress (WSS), turbulence intensity, embolic trajectories, and cerebral perfusion. Cannula depth, orientation, and tip design have emerged as potentially important determinants of intra-aortic flow behavior.Materials and methodsA structured narrative review of the literature was conducted. PubMed/MEDLINE, Scopus, and Web of Science were searched from January 1990 to April 2025. Keywords included combinations of "aortic cannulation," "cardiopulmonary bypass," "computational fluid dynamics," "wall shear stress," "turbulence," "atherosclerotic plaque," "cerebral perfusion," "microembolization," "gaseous emboli," "NIRS," and "transcranial Doppler." Studies were included if they evaluated hemodynamic effects of cannulation strategies using computational, in vitro, or clinical models. Articles not directly related to CPB intra-aortic flow dynamics were excluded.ResultsThe available evidence suggests that cannula positioning significantly influences intra-aortic flow behavior. Centrally aligned cannulation directed toward the descending thoracic aorta promotes axial flow and is associated with reduced jet-wall impingement and lower peak WSS. This configuration decreases arch turbulence and limits embolic transport toward supra-aortic vessels.ConclusionArterial cannulation strategy during CPB is a modifiable determinant of flow behavior and potential cerebral embolic exposure. Hemodynamically informed cannulation principles may contribute to intraoperative neuroprotection, although prospective clinical validation is still required.