Key result
Increases in heart rate led to significant changes in overall flow patterns and substantial increases in calculated wall shear stress, with effects dependent on both heart rate and aneurysm geometry.
Increases in heart rate substantially increase wall shear stress and alter flow patterns in intracranial aneurysms, though effects are highly dependent on specific aneurysm geometry.
Heart rate increases may elevate aneurysm wall shear stress; hypothesis-generating in animal models, human studies needed before clinical relevance.
Rupture of an intracranial aneurysm (IA) is frequently associated with intense physical exertion and/or emotional excitement, events that are typically also accompanied by sudden significant changes in both heart rate and blood pressure. Very few experimental studies of aneurysm hemodynamics have examined the impact on hemodynamic parameters in and around an aneurysm resulting from changes in heart rate. In order to further understanding these changes, as they relate to hemodynamic features that may contribute to rupture of an IA, we examined the characteristics of pulsatile flow in and around two "patient-specific" intracranial aneurysms at three different cardiac frequencies. Three dimensional X-ray angiographic data (3D-DSA) were used to reconstruct accurate and patient-specific aneurysm geometries. Then, computational fluid dynamics techniques were utilized to analyze the characteristics of blood flow in and around the two aneurysms. Physiologically realistic flow conditions, as measured by transcranial Doppler ultrasound, were used in the simulations. Our results showed that there were significant changes in the overall flow patterns (e.g., vortex formation and translation) associated with the changes of heart rates. In both aneurysms, the calculated wall shear stress exhibited substantial increases with an increase in heart rate. Our results suggest that the changes in local hemodynamic forces associated with variations in heart rate are dependent not only on the heart rate but also on the aneurysm geometry. This thus precludes applying our observations about the impact of variations in cardiac rate to aneurysms in general.
No takes yet. Share an insight, caveat, or question.
Jiang et al. (2009) studied Intracranial aneurysm (n=2). Varying heart rates was evaluated on Characteristics of pulsatile flow and wall shear stress. Increases in heart rate led to significant changes in overall flow patterns and substantial increases in calculated wall shear stress, with effects dependent on both heart rate and aneurysm geometry.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: