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

Abstract

Abstract-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 Ϸ25% in the youngest men to 8% in the oldest women. Amplification was higher in men (20Ϯ14%) than in women (13Ϯ12%; PϽ0.001) and decreased with age (PϽ0.001) 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 (Ϫ0.51 in women; Ϫ0.47 in men; both PϽ0.001). 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 (R 2 ϭ0.36). 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. Key Words: cardiovascular physiology Ⅲ blood pressure Ⅲ large arteries Ⅲ wave reflection Ⅲ hemodynamics I t has long been demonstrated that, when the blood pressure waveform is measured along the arterial tree, it changes continuously in shape and amplitude. 1,2 In large-and medium-sized arteries, the systolic upstroke of the wave generally becomes steeper from the central aorta toward the periphery, whereas the amplitude also increases, mainly through an increase in the peak value (systolic blood pressure) of the waveform. Overall, the minimum (diastolic) and mean (mean blood pressure) values, and especially the difference between both, change little from one location to the other. 3 These are well-known features described in physiological textbooks, and these phenomena can be explained on the basis of wave travel and reflection. The heart generates a forward-running pressure wave, which is reflected in the periphery. The measured pressure at any location is, thus, composed of this forward component, as well as backward components, arising from reflections. 4,5 The closer the blood pressure is measured to the reflection site (ie, the further in the periphery), the earlier the forward and backward waves will interact, leading to the steeper systolic upstroke and the more peaked appearance o...

Estimation of central systolic blood pressure using an oscillometric blood pressure monitor

“…17 Therefore, our results support that peripheral SBP2 closely approximates central aortic SBP, [11][12][13][14] and that central SBP may be increased by increased augmentation index, decreased arterial compliance, and increased arterial stiffness. 3,19 In this study, heart rate was not significantly associated with central aortic SBP and did not contribute to the prediction models. Although increased heart rate is associated with decreased augmentation index, 20 decreased arterial compliance, 21 and increased arterial stiffness, 22 incremental pacing was not associated with change of the central SBP.…”

“…Because arterial wave reflection and arterial compliance are the major determinants of the central-to-peripheral amplification of the pressure pulse, 3 the brachial pressure wave was further comprehensively analyzed to identify parameters, which are associated with arterial wave reflection and arterial compliance. SBP2 resulting from the arterial wave reflection was determined from the zero-crossing timings of the fourth derivative of the pressure wave.…”

“…1,2 The discrepancy between the central and peripheral blood pressures is mainly caused by the central-to-peripheral amplification of the pressure pulse and may magnify with administration of vasoactive agents. [2][3][4] Furthermore, recent evidence from epidemiological studies, 5,6 clinical observation, 7 and a large clinical trial 8 suggest that central blood pressure is more relevant than peripheral blood pressure in predicting target organ damage and cardiovascular outcomes. However, the implementation of central blood pressure in the daily practice of hypertension management may require the availability of its reliable measurements to both medical care providers in the clinics and patients at home.…”

Factors associated with brachial-ankle pulse wave velocity in the general population

“…Increased aortic stiffness causes the premature return of reflected waves in late systole and thus, causes an augmentation of central aortic pressure that may be closely related with left ventricular load. 12 This may partly explain the close relationship between the ECG voltage and baPWV. Moreover, increased aortic stiffness results in pressurerelated vascular damage in the renal circulation, which may cause glomerular hyperfiltration and albuminuria.…”

Closer to Noninvasive Out-of-Office Aortic Blood Pressure Assessment

“…Theoretically this should minimize miscalibration introduced by the brachial to radial PP amplification phenomenon. 3,6 Comments on the Present Study: Major …”