Background: We examined different characteristics of the second derivative of the finger photoplethysmogram (SDPTG) and brachial-ankle pulse wave velocity (BAPWV) for assessing arterial function in a large general population, along with the alteration of SDPTG in hypertension.
Methods: Finger SDPTG and BAPWV were measured in 848 (544 normotensive and 304 untreated hypertensive) subjects 34 to 88 years of age. For assessing SDPTG, we calculated the B:A and D:A ratios and the aging index (AGI), based on the height of the wave components. Using univariate and multivariate analyses, determinants of SDPTG indices and BAPWV as well as differences between normotensive and hypertensive subjects were evaluated.
Results: We found that BAPWV was independently and positively correlated with age, blood pressure (BP), heart rate (HR), and hemoglobin A1c. The D:A ratio and AGI showed a positive and the B:A ratio a negative independent correlation with age and BP. In contrast, the D:A ratio and AGI showed a negative and the B:A ratio a positive correlation with HR. The SDPTG indices, but not BAPWV, were independently associated with gender. The multivariate-adjusted D:A ratio, AGI, and BAPWV were significantly higher and the adjusted B:A ratio was lower in hypertensive than in normotensive subjects, and hypertensive subjects showed two-fold greater adjusted risks of having high D:A and low B:A ratios. The SDPTG indices and BAPWV were mildly correlated with each other in normotensive but not in untreated hypertensive subjects.
Conclusion: Although the SDPTG depends on various factors in a manner different from BAPWV, it may be useful for detecting vascular aging accelerated by hypertension.