Central Aortic Blood Pressure and Cardiovascular Risk

Abstract

The provocative proposition of “hypertension is a myth” has generated many a debate and editorial commentary.1,2 In contrast, the realities of high blood pressure and the associated cardiovascular risks have been ascertained from data obtained by the conventional brachial cuff sphygmomanometer. Notwithstanding the inherent limitations of the technique, there is yet no equivalent and suitable device that can be universally accepted to replace the cuff sphygmomanometer for practical and noninvasive measurement of arterial blood pressure in large population groups and with wide clinical applications. Attempts at complementing information obtained from cuff measurements have resorted to basic physiological studies in humans and experimental animals, which have shown that pulsatile blood flow in arteries can be described in terms of characteristics common to systems of wave propagation.3 These concepts explain the complex relationship between oscillatory blood pressure and flow, the difference in pressure wave shape, and the increase in pulse pressure between the aorta and peripheral arteries. Such wave propagation characteristics can be described in terms of mathematical entities known as transfer functions, with associated assumptions of stability and linearity.3,4 The study by McEniery et al in this issue of Hypertension 5 uses methodologies for both the cuff sphygmomanometer and transfer functions4 to determine central aortic pressure from the brachial cuff pressure measurement and the tonometric radial artery pressure pulse in >10 000 adults of age range 18 to 101 years. This is the largest study of its kind with conventional pressure measurements and pulse waveform data. The study allows analysis that can produce potentially groundbreaking results and poses important and possibly perplexing and challenging questions related not only to the role of central aortic pressure as an improved measure of the hemodynamic burden on the ejecting ventricle but also on the interpretation of guidelines for the management …