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(Hypertension. 2006;48:e108.)
© 2006 American Heart Association, Inc.

Letters to the Editor

Correlating Ambulatory Blood Pressure Measurements With Arterial Stiffness: A Conceptual Inconsistency?

InterCure Ltd, Lod, Israel

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

To the Editor:

There is a growing interest in characterizing arterial properties using noninvasive measurements. A new parameter, called the "Ambulatory Arterial Stiffness Index" (AASI), was derived recently from the linear relationship between systolic and diastolic blood pressure (BP) observed using 24-hour ambulatory measurements.^1,2 AASI has been hypothesized to be an index of arterial stiffness and shown to predict cardiovascular mortality. The purpose of this letter is to suggest that AASI is unlikely to reflect arterial stiffness and to propose an alternative view.

A plot of repeatedly measured diastolic versus systolic BP data shows a fairly linear relationship. The diastolic versus systolic, called hereafter "slope," can be derived using regression analysis. AASI is defined as l-slope.¹ Stating that AASI is an index of arterial stiffness is conceptually inconsistent, because the same slope may correspond with different values of arterial stiffness. By definition, a slope is determined by different BP levels and is independent of the distribution of data along the regression line. In contrast, arterial stiffness is known to increase for higher BP levels, which makes it sensitive to the distribution of BP data. For example, consider 24-hour ambulatory BP data of an individual. Excluding from the calculations a few high BP data points that occur along the regression line would not change the slope but would clearly shift 24-hour mean arterial stiffness to a lower value. This is true also for other pressure-dependent measures related to arterial stiffness as pulse wave velocity or augmentation index. Because this discrepancy cannot . . . [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]

				N. Westerhof, J.-W. Lankhaar, and B. E. Westerhof Letter to the Editor: Ambulatory Arterial Stiffness Index Is Not a Stiffness Parameter But a Ventriculo-Arterial Coupling Factor Hypertension, February 1, 2007; 49(2): e7 - e7. [Full Text] [PDF]

				Y. Li, J.-G. Wang, E. Dolan, E. O'Brien, L. Thijs, T. Nawrot, and J. A. Staessen Response to Correlating Ambulatory Blood Pressure Measurements With Arterial Stiffness: A Conceptual Inconsistency Hypertension, December 1, 2006; 48(6): e109 - e109. [Full Text] [PDF]