Correlation between estimated pulse wave velocity values from two equations in healthy and under cardiovascular risk populations

Introduction : Equations can calculate pulse wave velocity (ePWV) from
blood pressure values (BP) and age. The ePWV predicts cardiovascular
events beyond carotid-femoral PWV. We aimed to evaluate the correlation
between four different equations to calculate ePWV. Methods: The
ePWV was estimated utilizing mean BP (MBP) from office BP (MBPOBP) or
24-hour ambulatory BP (MBP24-hBP). We separated the whole sample into two
groups: individuals with risk factors and healthy individuals. The e-PWV
was calculated as follows:   We calculated the concordance
correlation coefficient (Pc) between e1-PWVOBP vs e2-PWVOBP, e1-PWV24-hBP
vs e2-PWV24-hBP, and mean values of e1-PWVOBP, e2-PWVOBP, e1-PWV24-hBP,
and e2-PWV24-hBP . The multilevel regression model determined how much the
ePWVs are influenced by age and MBP values. Results:  We analyzed
data from 1541 individuals; 1374 ones with risk factors and 167 healthy
ones. The values are presented for the entire sample, for risk-factor
patients and for healthy individuals, respectively. The correlation
between e1-PWVOBP with e2-PWVOBP and e1-PWV24-hBP with e2-PWV24-hBP was
almost perfect. The Pc for e1-PWVOBP vs e2-PWVOBP was 0.996 (0.995-0.996),
0.996 (0.995-0.996), and 0.994 (0.992-0.995); furthermore, it was 0.994
(0.993-0.995), 0.994 (0.994-0.995), 0.987 (0.983-0.990) to the
e1-PWV24-hBP vs e2-PWV24-hBP. There were no significant differences
between mean values (m/s) for e1-PWVOBP vs e2-PWVOBP 8.98±1.9 vs 8.97±1.8;
p=0.88, 9.14±1.8 vs 9.13±1.8; p=0.88, and 7.57±1.3 vs 7.65±1.3; p=0.5;
mean values are also similar for e1-PWV24-hBP vs e2-PWV24-hBP, 8.36±1.7 vs
8.46±1.6; p=0.09, 8.50±1.7 vs 8.58±1.7; p=0.21 and 7.26±1.3 vs 7.39±1.2;
p=0.34. The multiple linear regression showed that age, MBP, and age²
predicted more than 99.5% of all four e-PWV. Conclusion: Our data
presents a nearly perfect correlation between the values of two equations
to calculate the estimated PWV, whether utilizing office or ambulatory
blood pressure.