Observation of natural flexural pulse waves in retinal and carotid arteries for wall elasticity estimation

The risk of cardiovascular events is linked to arterial elasticity that can be estimated from the pulse wave velocity. This symmetric wave velocity is related to the wall elasticity through the Moens-Korteweg equation. However, ultrasound imaging techniques need improved accuracy, and optical measurements on retinal arteries produce inconsistent results. Here, we report the first observation of an antisymmetric pulse wave: the flexural pulse wave. An optical system performs in vivo wave velocity measurements on retinal arteries and veins. Velocity estimation ranges between 1 and 10 millimeter per second. The theory of guided waves confirms the existence of this wave mode and its low velocity. Natural flexural waves can also be detected at the bigger scale of a carotid artery using ultrafast ultrasound imaging. This second natural pulse wave has great potential of becoming a biomarker of blood vessel aging.

Automated summary

The risk of cardiovascular events is associated with the elasticity of arteries, which can be estimated from the pulse wave velocity. However, current ultrasound imaging techniques lack accuracy and optical measurements on retinal arteries yield inconsistent results. This study presents the discovery of an antisymmetric pulse wave called the flexural pulse wave, observed for the first time. Optical system measurements on retinal arteries and veins show a velocity range of 1-10 millimeters per second. This wave mode has potential as a biomarker for blood vessel aging, and it can also be detected using ultrafast ultrasound imaging on larger carotid arteries.