The dicrotic notch analyzed by a numerical model

• Published in: Computers in biology and medicine Vol. 72; pp. 54 - 64
• Main Authors: Politi, María Teresa, Ghigo, Arthur, Fernández, Juan Manuel, Khelifa, Ismaïl, Gaudric, Julien, Fullana, José María, Lagrée, Pierre-Yves
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.05.2016; Elsevier Limited; Elsevier
• Subjects: Adult; Biomechanics; Blood Pressure; Coronary vessels; Dicrotic notch; Engineering Sciences; Fluid mechanics; Heart; Humans; Hypotheses; Internal Medicine; Mechanics; Medical physiology; Models, Theoretical; Morphology; Numerical model; Other; Physics; Reflection wave; Vascular surgery; Veins & arteries; Medical physiology; Dicrotic notch; Numerical model; Reflection wave; Dicrotic notch. Reflection wave. Numerical model. Medical physiology
• ISSN: 0010-4825; 1879-0534
• DOI: 10.1016/j.compbiomed.2016.03.005

Divergent concepts on the origin of the dicrotic notch are widespread in medical literature and education. Since most medical textbooks explain the origin of the dicrotic notch as caused by the aortic valve closure itself, this is commonly transmitted in medical physiology courses. We present clinical data and numerical simulations to demonstrate that reflected pressure waves could participate as one of the causes of the dicrotic notch. Our experimental data from continuous arterial pressure measurements from adult patients undergoing vascular surgery suggest that isolated changes in peripheral vascular resistance using an intravenous bolus of phenylephrine (a selective alpha 1-receptor agonist and thus a potent vasoconstrictor) modify the dicrotic notch. We then explore the mechanisms behind this phenomenon by using a numerical model based on integrated axisymmetric Navier-Stokes equations to compute the hemodynamic flow. Our model illustrates clearly how modifications in peripheral artery resistance may result in changes in the amplitude of the dicrotic notch by modifying reflected pressure waves. We believe that this could be a useful tool in teaching medical physiology courses. •Aortic valve closure is the most widespread explanation for the dicrotic notch.•Reflected pressure waves may participate in forming the dicrotic notch.•A 1D numerical model based on Navier-Stokes equations can test this hypotheses.•Changes in terminal resistance modify reflected waves and thus the dicrotic notch.•Vasoconstrictors modify the morphology of the dicrotic notch in human subjects.