title: Retinal microvascular structure and function in patients with risk factors of atherosclerosis and coronary artery disease.
abstract: OBJECTIVE
  Retinal microvascular signs are markers of cardiovascular disease risk. There are limited data, on relationships between retinal microvascular signs and retinal microvascular endothelial function. We sought to determine the relationship of retinal vascular signs with retinal microvascular endothelial function in patients with or at high risk of coronary artery disease.
  
  
  METHODS
  Participants with atherosclerosis risk factors and coronary disease (n=258; mean age 57±11 years) were recruited to have static and dynamic retinal vascular assessment. Retinal arteriolar dilatation in response to flicker light (FI-RAD) was measured using the Digital Vessel Analyser and expressed as percentage increase over baseline diameter. Static retinal photographs were acquired utilising a digital fundus camera for measurement of central retinal artery and vein equivalent (CRAE and CRVE), arteriovenous nicking (AVN) and focal arteriolar narrowing (FAN).
  
  
  RESULTS
  Intra-class correlation coefficient was 0.82 for flicker-light induced retinal arteriolar dilatation. There were modest associations in retinal vascular measurements between eyes. For each 10 μm decrease in retinal arteriolar diameter, the absolute increase in FI-RAD was 0.28% (95% CI 0.11, 0.45; p=0.002) independent of age, gender and atherosclerosis risk factors. AVN and FAN were associated with attenuated FI-RAD (β=-0.67%; 95% CI -1.20, -0.15; p=0.012) and (β=-0.83%; 95% CI -1.44, -0.23; p=0.007) respectively after adjustment for age and gender.
  
  
  CONCLUSIONS
  Assessment of retinal microvascular endothelial function is reproducible and correlated with retinal microvascular structure and signs, independent of atherosclerosis risk factors. Assessment of retinal vascular structure and function may provide insights into atherosclerotic disease.
authors: Department of Cardiology, Austin Health, Heidelberg, VIC 3084, Australia; Department of Medicine, University of Melbourne, Australia.
authors: Ali H
authors: AH
authors: Al-Fiadh
authors: Department of Cardiology, Austin Health, Heidelberg, VIC 3084, Australia; Department of Medicine, University of Melbourne, Australia. Electronic address: omar.farouque@austin.org.au.
authors: Omar
authors: O
authors: Farouque
authors: Centre for Eye Research Australia, East Melbourne, VIC 3002, Australia; Department of Public Health, Yamagata University, Japan.
authors: Ryo
authors: R
authors: Kawasaki
authors: Centre for Eye Research Australia, East Melbourne, VIC 3002, Australia.
authors: T T
authors: TT
authors: Nguyen
authors: Department of Cardiology, Austin Health, Heidelberg, VIC 3084, Australia.
authors: Nazim
authors: N
authors: Uddin
authors: Department of Medicine, University of Melbourne, Australia.
authors: Melanie
authors: M
authors: Freeman
authors: Department of Medicine, University of Melbourne, Australia.
authors: Sheila K
authors: SK
authors: Patel
authors: Department of Cardiology, Austin Health, Heidelberg, VIC 3084, Australia; Department of Medicine, University of Melbourne, Australia.
authors: Louise M
authors: LM
authors: Burrell
authors: Centre for Eye Research Australia, East Melbourne, VIC 3002, Australia; Singapore Eye Research Institute, National University of Singapore, Singapore.
authors: Tien Y
authors: TY
authors: Wong
mesh_terms: D000368:Aged; D001160:Arterioles / Q000503:physiopathology / Q000648:ultrastructure; D050197:Atherosclerosis / Q000453:epidemiology*; D003324:Coronary Artery Disease / Q000453:epidemiology*; D004730:Endothelium, Vascular / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000648:ultrastructure; D012169:Retinal Vein / Q000648:ultrastructure; D012171:Retinal Vessels / Q000648:ultrastructure*; D012307:Risk Factors; D014664:Vasodilation; D014699:Venules / Q000648:ultrastructure
keywords: Coronary disease; Endothelial function; Microcirculation; Retinal vessels