In a simulation of 161 patients, lowering blood pressure significantly decreased standard CAVI (from 8.1 to 7.7, p=0.008), whereas the corrected CAVI0 remained independent of blood pressure changes.
Standard arterial stiffness indices (β and CAVI) are inherently blood pressure-dependent, which can be corrected using the proposed CAVI0 index to prevent erroneous conclusions in clinical trials.
Tasa de eventos absoluta: 7.7% vs 8.1%
valor p: p=0.008
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 β assume an exponential relationship between pressure (P) and diameter (d). We aim to demonstrate that, under this assumption, β 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 = Prefe, 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.
Spronck et al. (Thu,) conducted a other in Arterial stiffness (n=161). Blood pressure-lowering treatment (simulated) vs. Baseline (before blood pressure lowering) was evaluated on Cardio-ankle vascular index (CAVI) (p=0.008). In a simulation of 161 patients, lowering blood pressure significantly decreased standard CAVI (from 8.1 to 7.7, p=0.008), whereas the corrected CAVI0 remained independent of blood pressure changes.
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