Microstructural changes of longitudinal retinal venous profiles measured by retinal vessel analyzer in systemic hypertension

Abstract

Purpose: The Retinal Vessel Analyser (RVA) observes vessels in their dynamic state non‐invasively. We found earlier a significant increase in roughness along longitudinal vessel profiles with increasing age. Whether longitudinal retinal venous profiles in systemic hypertension (SH) are altered is investigated. Methods: 15 untreated SH‐patients (age 50,9±11,9 years) and 15 age matched healthy volunteers were examined. After baseline assessment a monochromatic (530‐600nm) rectangular flicker of 12.5 Hz was applied for 20 sec. In venous segments (1 mm length) vessel diameters were measured to obtain a longitudinal vessel profile. Results: Baseline average diameters and caliber range differed significantly in both groups (p<0,03) (median(1quartile; 3quartile)): SH: 164,4(151,8; 168,4)MU/ 33,5(21,6; 35,8)MU; control: 146,4(132,3; 152,1)MU/ 19,9(16,0; 23,6)MU. Average area under power spectra within the frequency band of 0,03‐0,065 Hz differed significantly at dilation (SH: 0,171(0,113; 0,351); control: 0,366(0,328; 0,490)); initial restoration (SH: 0,213(0,134; 0,359); control: 0,382(0,303; 0,514)) and restoration (SH: 0,252(0,128; 0,374); control: 0,425(0,311; 0,496))(p<0,03). Conclusions: The veins in SH seem pre‐dilated and pe‐stretched. The microstructure of longitudinal venous profiles in healthy volunteers and SH‐patients does not change in different phases of the reaction. In longitudinal venous profiles in SH low frequencies are more expressed and mid frequencies are less pronounced than in the control group. These microstructural changes in vessel profiles in SH‐patients might be an indication for alterations in the vascular endothelium, leading to impaired local perfusion and regulation.