Large Artery Stiffness Assessment Using SphygmoCor Technology

Abstract

Large artery stiffness assessment has been an integral part of the SphygmoCor technology since 1998. Aortic stiffness is approximated with non-invasive measurement of carotid-femoral pulse wave velocity, with improvements made with time to make the assessment procedure quicker and more user independent. Also standard in the devices is the ability to reliably calculate the central aortic waveform shape from a peripheral pressure waveform from either the brachial or radial artery. This waveform contains much information beyond peak and trough (systolic and diastolic pressure). Relative waveform features such as the augmentation index, wave reflection magnitude, reflection time index, and subendocardial viability ratio are parameters that are influenced by the stiffness of systemic arteries. This article briefly describes these parameters related to large artery stiffness and provides reference to validation and repeatability studies relative to the clinical use of the SphygmoCor devices. It is beyond the scope to review here the 424 original research articles that have employed SphygmoCor devices in measuring arterial stiffness. Instead, the method of measurement across the devices is described, including tonometry, volumetric displacement through cuff placement around limbs, and ambulatory monitoring. Key population and subpopulation studies are cited where the average stiffness parameter progression with age and gender, as measured by SphygmoCor devices, is quantified in the healthy and general population. Finally, with reference to guidelines from working groups on arterial stiffness and hypertension, the clinical utility of large artery stiffness measurement is discussed in the context of the arterial stiffness parameters provided by the SphygmoCor systems.