Beyond blood pressure: pulse wave analysis--a better way of assessing cardiovascular risk?

The study of the pulse pressure wave using the technique of applanation tonometry is becoming more popular as a method of studying vascular stiffness. This review aims to present the uses, potential uses, strengths and weaknesses of the technique of applanation tonometry to assess augmentation index and pulse wave velocity. This article shall briefly discuss the practicalities of applanation tonometry, the physiological factors affecting pulse wave velocity and pulse wave analysis, the changes in pulse wave velocity and pulse wave analysis with pharmacological interventions, and the use of applanation tonometry as a prognostic tool. Although the technique of applanation tonometry seems initially promising, several pertinent issues need to be addressed before it can be used reliably as a clinical tool. Importantly, the technique of applanation tonometry to derive the central waveform from noninvasively-acquired peripheral data needs to be prospectively validated. As stated in this review, the transfer function has been extensively validated using invasive data, whilst noninvasive data estimation of the ascending aortic blood pressure is less accurate.