Abstract
Purpose: :
Pulse wave velocity in large vessels has been extensively used 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 arterial disease. An in-vivo clinical method to characterise arterial stiffness of the central microcirculation was developed. Pulse wave velocity was measured in retinal arteries using the Dynamic Vessel Analyzer (DVA, Fa. IMEDOS, Jena, Germany). Whether this parameter is age-dependent in healthy volunteers was investigated.
Methods: :
Time dependent alterations of retinal vessel diameter were examined continuously by DVA in a randomly chosen eye of 10 young (26,0(23,5; 27,0) [median(1. quartile;3. quartile)] and 10 senior (67,0(61,3; 69,5) years old) anamnestically healthy volunteers. Two segments of a retinal artery were measured simultaneously. The phase delay between the pulsations of the segments was assessed. The distance between those segments was measured using retinal photographs with software VisualIS Fa. IMEDOS, Jena, Germany). The data was filtered and evaluated by methods of signal analysis.
Results: :
There was a significant difference in pulse wave velocity between both groups (p<0,01, U-Test). It amounted to 21,5(17,9; 34,6) mm/s in young volunteers and to 243,8(186,1; 347,7) mm/s in seniors. Retinal arterial elasticity (elasticity modulus) calculated on the base of these data amounted to 5,5(3,8; 12,5) Pa in young volunteers and to 607,5(329,8; 1426,8) Pa in seniors (p<0,05).
Conclusions: :
An important clinical parameter, pulse-wave velocity, can be measured in the central microcirculation in-vivo using a commercially available medical device. Pulse wave velocity in retinal vessels increases significantly with age. This represents the age-dependent increase in retinal arterial stiffness which is part of the general aging processes in the human vasculature and might be the basis of age related ocular vascular disorders. Quantifying pulse wave velocity of retinal vessels may be an indirect measure of the cerebral vasculature in health and systemic diseases.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • image processing • retina