Abstract TP481: Deep and Superficial Brain Arteries Flow Pattern Suggest Differential Risks to Systemic Hemodynamics

Abstract

Introduction: Penetrating arteries supplying the basal ganglia and the brain stem are often affected by chronic hypertension whereas distal branching arteries supplying the brain convexity and corona radiata may be injured by hypoperfusion. We hypothesized that under equal systemic flow dynamics, distal branching brain arteries will have a lower pressure peak than penetrating arteries. Methods: We used an Anatomically Detailed Arterial Network (ADAN) model to predict pressure waveforms for brain and systemic arteries. The anatomical details were obtained from published literature and match for an average man, height of 170 cms and body surface area of 1.65 m2. Arterial length and radius were obtained from published literature for each organ. Standard governing equations for the flow of an incompressible fluid in compliant pipes are considered in each arterial segment. Proper coupling conditions at junctions are also postulated, as well as terminal Windkessel models. Results: Compared to systemic arteries, brain arteries have an early peak in flow and pressure, followed by a gradual decline in flow and pressure over time (figure 1). The posterior parietal artery has the lowest MAP and pulse pressure of the four brain arteries tested, even if the pulsatility and resistance indices remained relatively the same. Consequently, the pressure pulse peak for the posterior parietal artery hovers around 80 mmhg compared with approximately 110 mmHg for the lenticulostriate arteries and the middle cerebral and basilar arteries. Lenticulostriate arteries had similar hemodynamic profiles to the large artery branches of the circle of Willis. Conclusion: Penetrating brain arteries are susceptible to high pressure remodeling because of their immediate branching from a large artery, while distal cortical arteries are more susceptible to hypoperfusion. These regional susceptibilities to systemic hemodynamic may influence brain health and contribute to neurodegeneration.