Pulse wave velocity and the second derivative of the finger photoplethysmogram in treated hypertensive patients: Their relationship and associating factors

Objectives: To clarify the factors influencing two measures of arterial stiffness, pulse wave velocity (PWV) and the second derivative of the finger photoplethysmogram (SDPTG), and to evaluate their relationship in treated hypertensive subjects. Subjects and methods: The subjects were 294 hypertensive patients aged 32-91 years (mean, 61.4 ± 10.5 years). After blood pressure (BP) was measured, carotid-femoral PWV and SDPTG were recorded with the subjects in the supine position, with the aid of an automatic device. For assessing SDPTG, we focused mainly on the ratios of the absolute value of the height of the early negative 'b' wave (B) and that of the late redecreasing 'd' wave (D) to that of the initial positive 'a' wave (A), namely the B:A and D:A ratios, and the aging index (AGI). Factors influencing PWV and SDPTG indices, and the relationship between PWV and SDPTG indices were evaluated by bivariate and multivariate analyses. Results: According to multiple linear regression analysis, age, systolic blood pressure (SBP), and heart rate (HR) were variables independently and positively correlated with PWV. The age and BP were significantly and independently related to SDPTG indices; there were positive correlations with the D:A ratio and AGI, and negative correlations with the B:A ratio. HR was correlated negatively with the D:A ratio and AGI, and positively with the B:A ratio. According to multiple logistic regression analysis, adjusted-odds ratios of high PWV, low B:A ratio, high D:A ratio, and high AGI were significantly elevated among the elderly and among the subjects with uncontrolled BP. Although PWV and the SDPTG indices were associated with common factors, including age and BP, bivariate analysis revealed that they were only weakly correlated with each other. Conclusions: The results suggest that in hypertensive patients, PWV and SDPTG provide different information about arterial properties at central and peripheral sites.