EVALUATION OF DEPENDENCE OF AGE AND PERIPHERAL BLOOD PRESSURE IN TWO PULSE WAVE VELOCITY ESTIMATION METHODS

Abstract

Objective: To evaluate the dependence of age and blood pressure (BP) on the estimated pulse wave velocity (PWV) by Mobil-o-Graph and an equation derived from the Reference Values for Arterial Stiffness Collaboration. Design and method: This study is a secondary analysis of a database from a cross-sectional study conducted in a specialized center in inner Brazil to diagnose and treat non-communicable diseases. We included individuals with hypertension and at least one risk factor, dyslipidemia, diabetes, smoking, body mass index (BMI) > = 30 kg/m2. Three accurate office BP measurements were made and calculated the average (OBP) using Microlife equipment BP3AC1-1PC (Onbo Electronic Co, Shenzhen, China). The average of four measures of office PWV (oPWV) was calculated using Mobil-O-Graph device (I.E.M., Stolberg, Germany). Also, estimated PWV (ePWV) was calculated by utilizing age and the mean arterial pressure of OBP (MBP) from an equation derived by the Reference Values for Arterial Stiffness Collaboration as follows: ePWV = 9.58748315543126-0.402467539733184*age+4.56020798207263*10-3*age2-2.6207705511664*10-5*age2*MBP+3.1762450559276*10-3*age*MBP-1.8321025*MBP Five multilevel regression models were used to determine how much ePWV and PWV depend on age, age2, systolic OBP, MBP, and all of them together. Forkman test was used to compare the coefficient of determination (R2). Results: Table 1 shows the main clinical characteristics of the sample. Table 2 demonstrates the results for comparing the coefficient of determination for ePWV and oPWV. Age determines 75% of ePWV variance and 85% of oPWV (p = 0.0001), age2 78% of ePWV and 90% of oPWV (p = 0.0001), SBP 41% of ePWV and 18% of oPWV (p<0.0001), MBP 24% of ePWV and 5% of oPWV (p<0.0001). The model 5 shows that the variables studied together determine better the variance of ePWV (99%) than oPWV (94%). Conclusions: Age, age2, SBP, and MBP explain almost the overall variance of ePWV and oPWV. However, ePWV is significantly more dependent on BP than oPWV, which is considerably more dependent on age.