Arterial stiffness index beta and cardio-ankle vascular index inherently depend on blood pressure but can be readily corrected

Bart Spronck, Alberto P. Avolio, Isabella Tan, Mark Butlin, Koen D. Reesink, Tammo Delhaas

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Objectives: Arterial stiffness index β and cardio-ankle vascular index (CAVI) are widely accepted to quantify the intrinsic exponent (β0) of the blood pressure (BP)-diameter relationship. CAVI and b assume an exponential relationship between pressure (P) and diameter (d). We aim to demonstrate that, under this assumption, b and CAVI as currently implemented are inherently BP-dependent and to provide corrected, BP-independent forms of CAVI and β. Methods and results: In P = Prefeβ0[(d/dref)-1], usually reference pressure (Pref) and reference diameter (dref) are substituted with DBP and diastolic diameter to accommodate measurements. Consequently, the resulting exponent is not equal to the pressure-independent β0. CAVI does not only suffer from this 'reference pressure' effect, but also from the linear approximation of dP=dd. For example, assuming β0 = 7, an increase of SBP/DBP from 110/70 to 170/120 mmHg increased β by 8.1% and CAVI by 14.3%. We derived corrected forms of β and of CAVI (CAVI0) that indeed did not change with BP and represent the pressure-independent β0. To substantiate the BP effect on CAVI in a typical follow-up study, we realistically simulated patients (n = 161) before and following BP-lowering 'treatment' (assuming no follow-up change in intrinsic β0 and therefore in actual P-d relationship). Lowering BP from 160 ± 14/111 ± 11 to 120 ± 15/79 ± 11 mmHg (p < 0.001) resulted in a significant CAVI decrease (from 8.1 ± 2.0 to 7.7 ± 2.1, p = 0.008); CAVI0 did not change (9.8 ± 2.4 and 9.9 ± 2.6, p = 0.499). Conclusion: β and CAVI as currently implemented are inherently BP-dependent, potentially leading to erroneous conclusions in arterial stiffness trials. BP-independent forms are presented to readily overcome this problem.

LanguageEnglish
Pages98-104
Number of pages7
JournalJournal of Hypertension
Volume35
Issue number1
DOIs
Publication statusPublished - Jan 2017

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Vascular Stiffness
Ankle
Blood Vessels
Blood Pressure
Pressure

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@article{5dd97e1cefc04d4a9f4f59a4ee2964fb,
title = "Arterial stiffness index beta and cardio-ankle vascular index inherently depend on blood pressure but can be readily corrected",
abstract = "Objectives: Arterial stiffness index β and cardio-ankle vascular index (CAVI) are widely accepted to quantify the intrinsic exponent (β0) of the blood pressure (BP)-diameter relationship. CAVI and b assume an exponential relationship between pressure (P) and diameter (d). We aim to demonstrate that, under this assumption, b and CAVI as currently implemented are inherently BP-dependent and to provide corrected, BP-independent forms of CAVI and β. Methods and results: In P = Prefeβ0[(d/dref)-1], usually reference pressure (Pref) and reference diameter (dref) are substituted with DBP and diastolic diameter to accommodate measurements. Consequently, the resulting exponent is not equal to the pressure-independent β0. CAVI does not only suffer from this 'reference pressure' effect, but also from the linear approximation of dP=dd. For example, assuming β0 = 7, an increase of SBP/DBP from 110/70 to 170/120 mmHg increased β by 8.1{\%} and CAVI by 14.3{\%}. We derived corrected forms of β and of CAVI (CAVI0) that indeed did not change with BP and represent the pressure-independent β0. To substantiate the BP effect on CAVI in a typical follow-up study, we realistically simulated patients (n = 161) before and following BP-lowering 'treatment' (assuming no follow-up change in intrinsic β0 and therefore in actual P-d relationship). Lowering BP from 160 ± 14/111 ± 11 to 120 ± 15/79 ± 11 mmHg (p < 0.001) resulted in a significant CAVI decrease (from 8.1 ± 2.0 to 7.7 ± 2.1, p = 0.008); CAVI0 did not change (9.8 ± 2.4 and 9.9 ± 2.6, p = 0.499). Conclusion: β and CAVI as currently implemented are inherently BP-dependent, potentially leading to erroneous conclusions in arterial stiffness trials. BP-independent forms are presented to readily overcome this problem.",
author = "Bart Spronck and Avolio, {Alberto P.} and Isabella Tan and Mark Butlin and Reesink, {Koen D.} and Tammo Delhaas",
year = "2017",
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language = "English",
volume = "35",
pages = "98--104",
journal = "Journal of Hypertension",
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publisher = "Lippincott Williams & Wilkins",
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Arterial stiffness index beta and cardio-ankle vascular index inherently depend on blood pressure but can be readily corrected. / Spronck, Bart; Avolio, Alberto P.; Tan, Isabella; Butlin, Mark; Reesink, Koen D.; Delhaas, Tammo.

In: Journal of Hypertension, Vol. 35, No. 1, 01.2017, p. 98-104.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Arterial stiffness index beta and cardio-ankle vascular index inherently depend on blood pressure but can be readily corrected

AU - Spronck, Bart

AU - Avolio, Alberto P.

AU - Tan, Isabella

AU - Butlin, Mark

AU - Reesink, Koen D.

AU - Delhaas, Tammo

PY - 2017/1

Y1 - 2017/1

N2 - Objectives: Arterial stiffness index β and cardio-ankle vascular index (CAVI) are widely accepted to quantify the intrinsic exponent (β0) of the blood pressure (BP)-diameter relationship. CAVI and b assume an exponential relationship between pressure (P) and diameter (d). We aim to demonstrate that, under this assumption, b and CAVI as currently implemented are inherently BP-dependent and to provide corrected, BP-independent forms of CAVI and β. Methods and results: In P = Prefeβ0[(d/dref)-1], usually reference pressure (Pref) and reference diameter (dref) are substituted with DBP and diastolic diameter to accommodate measurements. Consequently, the resulting exponent is not equal to the pressure-independent β0. CAVI does not only suffer from this 'reference pressure' effect, but also from the linear approximation of dP=dd. For example, assuming β0 = 7, an increase of SBP/DBP from 110/70 to 170/120 mmHg increased β by 8.1% and CAVI by 14.3%. We derived corrected forms of β and of CAVI (CAVI0) that indeed did not change with BP and represent the pressure-independent β0. To substantiate the BP effect on CAVI in a typical follow-up study, we realistically simulated patients (n = 161) before and following BP-lowering 'treatment' (assuming no follow-up change in intrinsic β0 and therefore in actual P-d relationship). Lowering BP from 160 ± 14/111 ± 11 to 120 ± 15/79 ± 11 mmHg (p < 0.001) resulted in a significant CAVI decrease (from 8.1 ± 2.0 to 7.7 ± 2.1, p = 0.008); CAVI0 did not change (9.8 ± 2.4 and 9.9 ± 2.6, p = 0.499). Conclusion: β and CAVI as currently implemented are inherently BP-dependent, potentially leading to erroneous conclusions in arterial stiffness trials. BP-independent forms are presented to readily overcome this problem.

AB - Objectives: Arterial stiffness index β and cardio-ankle vascular index (CAVI) are widely accepted to quantify the intrinsic exponent (β0) of the blood pressure (BP)-diameter relationship. CAVI and b assume an exponential relationship between pressure (P) and diameter (d). We aim to demonstrate that, under this assumption, b and CAVI as currently implemented are inherently BP-dependent and to provide corrected, BP-independent forms of CAVI and β. Methods and results: In P = Prefeβ0[(d/dref)-1], usually reference pressure (Pref) and reference diameter (dref) are substituted with DBP and diastolic diameter to accommodate measurements. Consequently, the resulting exponent is not equal to the pressure-independent β0. CAVI does not only suffer from this 'reference pressure' effect, but also from the linear approximation of dP=dd. For example, assuming β0 = 7, an increase of SBP/DBP from 110/70 to 170/120 mmHg increased β by 8.1% and CAVI by 14.3%. We derived corrected forms of β and of CAVI (CAVI0) that indeed did not change with BP and represent the pressure-independent β0. To substantiate the BP effect on CAVI in a typical follow-up study, we realistically simulated patients (n = 161) before and following BP-lowering 'treatment' (assuming no follow-up change in intrinsic β0 and therefore in actual P-d relationship). Lowering BP from 160 ± 14/111 ± 11 to 120 ± 15/79 ± 11 mmHg (p < 0.001) resulted in a significant CAVI decrease (from 8.1 ± 2.0 to 7.7 ± 2.1, p = 0.008); CAVI0 did not change (9.8 ± 2.4 and 9.9 ± 2.6, p = 0.499). Conclusion: β and CAVI as currently implemented are inherently BP-dependent, potentially leading to erroneous conclusions in arterial stiffness trials. BP-independent forms are presented to readily overcome this problem.

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DO - 10.1097/HJH.0000000000001132

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EP - 104

JO - Journal of Hypertension

T2 - Journal of Hypertension

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