|Title||Methods for evaluation of retinal microvascular abnormalities associated with hypertension/sclerosis in the Atherosclerosis Risk in Communities Study.|
|Publication Type||Journal Article|
|Year of Publication||1999|
|Authors||Hubbard LD, Brothers RJ, King WN, Clegg LX, Klein R, Cooper LS, Sharrett AR, Davis MD, Cai J|
|Date Published||1999 Dec|
|Keywords||Aged, Blood Pressure, Capillaries, Coronary Artery Disease, Cross-Sectional Studies, Diagnostic Techniques, Ophthalmological, Female, Fundus Oculi, Humans, Hypertension, Image Processing, Computer-Assisted, Male, Middle Aged, Photography, Reproducibility of Results, Retinal Diseases, Retinal Vessels, Risk Factors, Sclerosis, United States|
OBJECTIVE: To develop protocols to photograph and evaluate retinal vascular abnormalities in the Atherosclerosis Risk in Communities (ARIC) Study; to test reproducibility of the grading system; and to explore the relationship of these microvascular changes with blood pressure.
DESIGN: Population-based, cross-sectional study.
PARTICIPANTS: Among 4 examination centers, 11,114 participants (48-73 years of age) at their third triennial examination, after excluding persons with diabetes from this analysis.
METHODS: One eye of each participant was photographed by technicians with nonmydriatic fundus cameras. Reading center graders evaluated focal arteriolar narrowing, arteriovenous (AV) nicking, and retinopathy by examining slides on a light box and measured diameters of all vessels in a zone surrounding the optic disc on enhanced digitized images. To gauge generalized narrowing, vessel diameters were combined into central arteriolar and venular equivalents with formulas adjusting for branching, and the ratio of equivalents (A/V ratio) was calculated.
MAIN OUTCOME MEASURES: Retinal vascular abnormalities, mean arteriolar blood pressure (MABP).
RESULTS: Among 11,114 participants, photographs were obtained of 99%, with quality sufficient to perform retinal evaluations in 81%. In the 9040 subjects with usable photographs, A/V ratio (lower values indicate generalized arteriolar narrowing) ranged from 0.57 to 1.22 (median = 0.84, interquartile range = 0.10), focal arteriolar narrowing was found in 7%, AV nicking in 6%, and retinopathy in 4%. Because of attrition of subjects and limitation of methods, prevalence of abnormality was likely underestimated. Controlling for gender, race, age, and smoking status, these retinal changes were associated with higher blood pressure. For every 10-mmHg increase in MABP, A/V ratio decreased by 0.02 unit (P
CONCLUSION: Protocols have been developed for nonmydriatic fundus photography and for evaluation of retinal vascular abnormalities. Several microvascular changes were significantly associated with higher blood pressure; follow-up will show whether these are predictive of later cerebrovascular or cardiovascular disease independently of other known risk factors.
|Grant List||N01-HC-35125 / HC / NHLBI NIH HHS / United States |
N01-HC-35126 / HC / NHLBI NIH HHS / United States
N01-HC-55015 / HC / NHLBI NIH HHS / United States