Dynamic retinal arterial oscillations are changed in old and very old adults

Abstract

Purpose : Retinal vessels are similar to cerebral vessels in their structure and function. We demonstrated previously that non-stimulated dynamic retinal arterial oscillations (pulsations and vasomotions) are changed in healthy adults with age, in primary open angle glaucoma, in diabetes mellitus type 1 and in Alzheimer’s disease. Whether this dynamic retinal arterial behavior is altered in healthy elderly people over 70 years old is investigated.

Methods : Study participants were examined by Dynamic Vessel Analyzer (IMEDOS Systems): 28 medically validated healthy elderly volunteers 70 – 85 years old: 75.3(72.8 – 79.2) [median(1^st quartile – 3^rd quartile)] formed HEV-group and 31 validated healthy middle-aged adults 50 – 65 years old: 56.8(52.3 – 61.0) belonged to the control HMA-group. Oscillatory temporal changes of retinal vessel diameters were assessed during 40 s and were evaluated using mathematical signal analysis as well as non-parametric statistics.

Results : The relative to the vessel diameter magnitude of arterial vasomotions with period > 1.5 s was similar in both groups: 4.7%(3.5 – 6.8%) in HEV vs. 4.3%(3.4% – 5.6%) in HMA group, p=0.485. Average period of arterial vasomotions was shorter in HEV than in HMA: 4.7(3.4 – 5.8) s vs. 6.1(4.1 – 8.5) s, p = 0.012. Power spectra of retinal arterial oscillations differed between the groups at several frequency ranges. Especially within low frequency range up to 0.2 Hz (~ 1 – 12 osc./min) HMA oscillations, characterized by the normalized area under the power spectrum, prevailed over HEV oscillations: p < 0.005, see the figure. Moreover low frequency vasomotions were less regular in HEV with the coefficient of periodicity of 0.11(0.08 – 0.27) vs. 0.16(0.10 – 0.52) in HMA, p = 0.03.

Conclusions : Functional and morphological alterations of retinal arteries in old and very old adults are shown using a non-invasive in-vivo imaging technique. Low frequency arterial oscillations relate to lymphatic vessels’ pulsations as well as to Mayer waves and other vascular regulatory mechanisms. The impairment of this dynamic microvascular regulation in elderly volunteers might represent a manifestation of higher microvascular risk and be a reason for predisposition to some related diseases in advanced age. Especially the results are consistent with the amyloid clearance hypothesis of substrates being cleared from the brain along paravascular pathways due to low frequency vascular pulsation.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.