CORRELATION BETWEEN ESTIMATED PULSE WAVE VELOCITY FROM DERIVATED FROM REFERENCE OR HEALTHY POPULATION EQUATION AMONG INDIVIDUALS COM CARDIOVASCULAR RISK FACTORS

Abstract

Objective: To evaluate the correlation between estimated pulse wave velocity (ePWV) from two different equations in individuals with cardiovascular (CV) risk factors. Design and method: It selected five hundred sixty-five patients who presented at least one cardiovascular risk factor among treated hypertension, an elevated BP (cut off 140–90 mmHg), diabetes, dyslipidemia, smoking, body, and abdominal obesity. Using an automatic device, a non-physician trained observer performed three sequential BP measurements. The ePWV was calculated from age and mean blood pressure (MBP). Two equations derived from reference population (equation 1) and healthy population (equation 2) estimated ePWV (Greeve et al.). Eq. (1) = 9.58748315543126–0.402467539733184*age+4.56020798207263*10–3*age2–2.6207705511664*10-5*age*MBP+3.1762450559276*10-3*age*MBP-1.83215068503821*10-2MBP. Eq. (2) = 4.62–0.13*age+0.0018*age2+0.0006*age*MBP+0.0284*MBP. MBP was calculated as diastolic BP + 0.4 (ystolic BP - diastolic BP). We calculated the mean ePWV with both equations, performed a t-test to compare the means. The concordance correlation coefficient Pc evaluated the precision and accuracy between the measurements. We used the Bland Altman plot to assess an agreement between two ePWV better. Results: The Clinical characteristics of the sample: mean age 48.9 ± 13.9 years, 282 (49.9%) women, 219 (38.8%) treated hypertensives, 161 (28.5%) non treated hypertensives, 94 normotensives (16.6%), 38 (6.7%) masked hypertensives, 53 (9.4%) white coat hypertensives, 187 (33.1%) with dyslipidemia, 69 (12.2%) diabetics, 243 (43.1%) obese, 335 (60.3%) with waist circumference at risk, 47 smokers (8.3%). Figure 1 shows the Scatter diagram of correlation between epWV Eq. (1) and Eq. (2). The concordance correlation coefficient was 0.996 (95%CI: 0.995 – 0.997); Pearson coefficient p (precision) = 0.996; bias correction factor Cb (accuracy) = 0.999. On Figure 2 the Bland Altman plot considering the Eq. (1) as a gold standard demonstrates the agreement between two measurements. The mean difference was 0.03 ((95%CI: -0.28 – 0.33). There was no difference in ePWV with Eq. (1) - 9.17 ± 1.80 m/s and utilizing Eq. (2) - 9.14 ± 1.77 m/s (p = 0.77). Conclusions: Our data indicated an almost perfect correlation and values equivalency between ePWV from Eqs. (1) and 2. Therefore both equations could be utilized in individuals with cardiovascular risk factors to estimate PWV.