Age-Related Changes in Specific Harmonic Indices of Pressure Pulse Waveform

摘要

The central elastic arteries and the peripheral muscular arteries are different In their responses to aging. Aorta stiffens in much larger extent with age than peripheral arteries do. Peripheral blood pressure indices such as pulse pressure (PP) or augmentation index (AI) were preferred as surrogates in assessing arterial stiffness for clinical convenience. AI and PP both increase progressively with age. In this study, we present a harmonic based pulse waveform analysis method which may give similar result about central pressure as augmentation index. This method avoids the extra but necessary manipulations such as flow measuring, 4~(th) de-rivative of pressure wave in determining the inflection point, the second systolic peak for augmentation index calculating, all these manipulations can introduce error. The non-invasive peripheral pulse waveforms copied from published reports for several ageing studies were analyzed. The mean pulse height All and the harmonic proportion of the 1~(st) harmonic C1 increased but the harmonic proportion of the 3~(rd) harmonic C3 and the harmonic proportion of the 4~(th) harmonic C4 decreased with ageing. Aging had no significant effect on the harmonic proportion of the 2~(nd) harmonic C2. Among all these harmonic indices, AO, the mean pulse pressure increased dramatically since the 6th decade. These results suggest that AO is related to aorta stiffen or PP sensitive. The gradual increasing of C1 and gradual decreasing of C3 and C4 by ageing suggest that C1, C3 and C4 could be similar to AI; it corresponds to the pressure pulse naveform affected from ageing. The harmonic indices could be clinically useful in noninvasive cardio risk assessing for the elderly patients.