Implementation of the “Vascular Age Index” for the interpretation of applanation tonometry

Abstract

Background The application of pulse wave analysis in clinical practice is significantly limited due to the difficulties with evaluation of obtained data. The aim of the study was to propose the new index named “Vascular Age Index” for the improvement and simplification of pulse wave analysis.

Material and methods We examined male and female persons aged from 25 to 76. 128 normotensive participants (the control group, CG) and 150 patients with essential hypertension (EH) were subdivided into subgroups of 25–44, 45–64 and 65 or more years. Each of them included 50 patients. The exception was the oldest subgroup of CG consisting of 28 persons. All participants underwent office blood pressure measurement by automatic blood pressure monitor “Omron 3” and pulse wave analysis carried out with «Sphygmocor XCEL» equipment (AtCor Medical, Australia). Besides common parameters of pulse wave such as augmentation index (AIx) and pulse wave velocity (PWV) the new indicator — “Vascular Age Index” was determined in all persons by the formula: VAI (year) = PWV × AIx ÷ 20.

Results All studied parameters of pulse wave showed strong relationship with age, but the relationship of VAI with age was superior in its strength and significance. It was especially strong (r = 0.90; p < 0.001) in normotensive patients. The values of VAI obtained in subjects of the control group were approaching to the calendar age, and in patients with hypertension — often exceeded it.

Conclusions Our data confirmed the relationship between AIx and PWV on the one hand, and age and blood pressure on the other. It was shown that in patients of 25–44 years pathological changes of central pulse wave parameters could serve as an additional argument for the diagnosis of hypertension. VAI significantly simplifies the interpretation of central pulse wave study and increases the compliance. Moreover, the diagnostic accuracy of VAI application is rather high. Thus, the implementation of VAI in the routine practice may be recommended.