Pulse wave velocity in retinal arteries of healthy volunteers

Measurement of pulse wave velocity (PWV) in large vessels has been used extensively in clinical practice as an indirect measure of arterial stiffness and an indicator of cardiovascular risk factors. Arterial stiffness increases with age and in coronary artery disease. An in vivo clinical method to characterise arterial stiffness of the central microcirculation was developed.

Time-dependent alterations of retinal vessel diameter were examined by the dynamic vessel analyzer in a randomly chosen eye of 10 young (26.0 (23.5, 27.0) years old (median (1st quartile, 3rd quartile)) and 10 old (67.0 (61.3, 69.5)) years old) healthy volunteers. Two segments of a retinal artery were measured simultaneously. The distance between the segments was measured using retinal photographs. The data were filtered and analysed using signal analysis methods in order to calculate PWV in the assessed retinal artery (rPWV).

rPWV differed significantly between young (21.5 (17.9, 4.6) mm/s) and old (243.8 (186.1, 347.7) mm/s) volunteers: (p=0.0001, Mann-Whitney test with Bonferroni correction).

This study demonstrates a higher rPWV in elderly people than in young people. Therefore this new parameter resembles large artery PWV. This suggests that dynamic in vivo imaging of the central microcirculation enables the measurement of local microvascular stiffness with a commercially available medical device.