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(Hypertension. 2007;49:e7.)
© 2007 American Heart Association, Inc.

Letters to the Editor

Letter to the Editor

Ambulatory Arterial Stiffness Index Is Not a Stiffness Parameter But a Ventriculo-Arterial Coupling Factor

Laboratory for Physiology, and Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands

Jan-Willem Lankhaar

Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands

Berend E. Westerhof

BMEYE BV, Amsterdam, the Netherlands

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

Recent hypertension research has shown that large artery compliance is an important determinant of systolic pressure, pulse pressure, and cardiovascular disease. Many methods exist to determine compliance or its inverse, arterial stiffness; the time constant of the aortic pressure decay in diastole, the ratio of stroke volume over pulse pressure, and pulse wave velocity are among the most used. These methods require either invasive measurements or 2 simultaneous measurements and are not practical to use in epidemiological studies or in night–day variations. Dolan et al¹ recently suggested the use of the Ambulatory Arterial Stiffness Index (AASI), defined as 1 minus the slope of the (linear) relation between diastolic and systolic pressure, as a measure of arterial stiffness. The AASI is easy to measure noninvasively and over long time periods. The AASI, although associated with pulse pressure, augmentation index, and other measures of arterial stiffness, was criticized by Laurent,² Benetos and Lacolley,³ and Gavish⁴ and defended by Dolan et al.¹ Thus, the question of whether AASI is a proper arterial stiffness parameter has not been answered.

Here we derive the AASI from basic principles. The ratio of stroke volume, SV, over pulse pressure, PP, is a measure of total arterial compliance: C=SV/PP, or PP=SV/C. The ratio of mean pressure, P_m, and cardiac output, Q, is a measure of systemic vascular resistance, R. With SV times heart rate, HR, being cardiac output, it follows that P_m=. . . [Full Text of this Article]

This article has been cited by other articles:

				B. Gavish, I. Z. Ben-Dov, and M. Bursztyn Ambulatory Arterial Stiffness Index Is Not a Specific Marker of Reduced Arterial Compliance Hypertension, August 1, 2007; 50(2): e18 - e18. [Full Text] [PDF]

				Y. Li, J.-G. Wang, E. Dolan, E. O'Brien, T. W. Hansen, H. Ibsen, M. Kikuya, Y. Imai, T. Richart, L. Thijs, et al. Letter to the Editor: Response to Arterial Stiffness Index Is Not a Stiffness Parameter But a Ventriculo-Arterial Coupling Factor Hypertension, February 1, 2007; 49(2): e8 - e9. [Full Text] [PDF]