Amplification of the Pressure Pulse in the Upper Limb in Healthy, Middle-aged Men and Women

Central-to-peripheral amplification of the pressure pulse leads to discrepancies between central and brachial blood pressures. This amplification depends on an individual's hemodynamic and (patho)physiological characteristics. The aim of this study was to assess the magnitude and correlates of central-to-peripheral amplification in the upper limb in a healthy, middle-aged population (the Asklepios Study). Carotid, brachial, and radial pressure waveforms were acquired noninvasively using applanation tonometry in 1873 subjects (895 women) aged 35 to 55 years. Carotid, brachial, and radial pulse pressures were calculated, as well as the absolute and relative (with carotid pulse pressure as reference) amplifications. With subjects classified per semidecade of age, carotid-to-radial amplification varied from approximately 25% in the youngest men to 8% in the oldest women. Amplification was higher in men (20+/-14%) than in women (13+/-12%; P<0.001) and decreased with age (P<0.001) in both. Amplification over the brachial-to-radial path contributed substantially to the total amplification. In univariate analysis, the strongest correlation was found with the carotid augmentation index (-0.51 in women; -0.47 in men; both P<0.001). In a multiple linear regression model with carotid-to-radial amplification as the dependent variable, carotid augmentation index, total arterial compliance, and heart rate were identified as the 3 major determinants of upper limb pressure amplification (R2=0.36). We conclude that, in healthy middle-aged subjects, the central-to-radial amplification of the pressure pulse is substantial. Amplification is higher in men than in women, decreases with age, and is primarily associated with the carotid augmentation index.