Calibrated ascending aortic pressure waves can be derived from the radial pulse using a generalised transfer function

Brachial-to-radial SBP amplification

“…Our data support two previous postulations: first, the assumption of minimal B-R-SBPAmp contributes to underestimation of central SBP [15], and second, this assumption may inflate the true level of central-to-brachial SBP amplification [21]. Importantly, central-to-radial SBP amplification decreased with ageing only when radial SBP was used to calibrate radial waveforms and the magnitude of amplification is comparable to several invasive catheter studies that simultaneously measured ascending aortic and radial SBP [10,17,18,36,37].…”

Prospective Evaluation of a Method for Estimating Ascending Aortic Pressure From the Radial Artery Pressure Waveform

“…In the present study, correspondence for matching between manometer systems was checked before recording of data in every patient ( Figure 1) and was shown to be adequate. The difference between central (aortic) and peripheral (radial) systolic pressures was similar to that in our 2 previous studies 7, 37 and was associated with a similar substantial difference in pulse pressure.…”

“…Three previous validation studies [37][38][39] have been reported that used the original system. All gave results similar to those reported here, although in far smaller studies.…”

“…All were identified as having possible deficiencies before commencement of the present study. In our initial study, 37 pressure waves were digitized by hand, and data were analyzed from a retrospectively collected series. In a second study, 38 changes in the estimated aortic wave mirrored those seen in the measured aortic pulse, but there were quantitative differences that could not be explained; one possible explanation was a mismatch between the catheter-tip manometer for aortic pressure recording and the fluid-filled catheter for radial recording.…”

Arterial stiffness, hypertension and diabetes mellitus

“…The peripheral waveform is then transformed into the corresponding central arterial waveform, using Fourier analysis, and a validated generalised transfer factor based on data obtained from invasive recordings. [20][21][22][23] Augmentation index (AIx), a measure of systemic arterial stiffness, can then be calculated as the difference between the first and second systolic peaks expressed as a percentage of the pulse pressure, and central pressure derived. 18 Moreover, by gating measurements to the R wave of an ECG, and making recordings at two sites, PWV can also be measured.…”