Abstract
Background and purpose: Cerebral circulation is robustly controlled. There may be differences in autoregulation between hypertensive and normotensive subjects. However, auto-regulation in cerebral circulation is poorly reported because of difficulty in assessment. The purpose of this study was to characterize pulse wave reflection from the head in hypertensive and normotensive subjects by using wave intensity.
Methods: Using an ultrasonic system, we measured common carotid arterial wave intensity (WI), stiffness parameter (β), and volume flow rate (Q) at rest in 91 hypertensive patients (HT) and age matched normal subjects (Norm).
Results: Both in Norm and HT, magnitude of reflection (NA) did not depend on age. NA was considerably greater in HT than in Norm (P < 0.0001). NA was correlated with the maximum pressure in Norm (r = 0.36, p = 0.0009), but not in HT. NA increased with the maximum velocity (max U) considerably in HT (r = 0.51, p < 0.0001), but slightly in Norm (r = 0.32, p = 0.004). Both in Norm and HT, max U has a tendency to decrease with an increase in β, but not significantly. In Norm, NA did not depend on β. In HT, however, NA unexpectedly decreased with an increase in β (r = 0.21, p < 0.05).
Conclusions: Increased reflection from the head indicates enhanced auto-regulation of blood flow in HT. The magnitude of reflection depended on the maximum velocity rather than the maximum pressure in HT, which suggests the regulation of blood flow dominates that of blood pressure in HT. Common carotid arterial WI has the potential for analyzing the mechanism of regulation of cerebral circulation.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Niki, K., Sugawara, M. (2009). Characteristics of Pulse Wave Reflection from the Cerebral Circulation in Hypertension - Analysis Using Wave Intensity. In: Dössel, O., Schlegel, W.C. (eds) World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany. IFMBE Proceedings, vol 25/4. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-03882-2_200
Download citation
DOI: https://doi.org/10.1007/978-3-642-03882-2_200
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-03881-5
Online ISBN: 978-3-642-03882-2
eBook Packages: EngineeringEngineering (R0)