Age-related macular degeneration is associated with increased vascular endothelial growth factor, hemorheology and endothelial dysfunction

Objective: To investigate laboratory evidence of abnormal angiogenesis, hem orheologic factors, endothelial damage/dysfunction, and age-related macular degeneration (ARMD). Design: Comparative cross-sectional study. Participants: We studied 78 subjects (26 men and 52 women; mean age 74 year s; standard deviation [SD] 9.0) with ARMD attending a specialist referral c linic. Subjects were compared with 25 healthy controls (mean age, 71 years; SD, 11). Intervention and Outcome Measures: Levels of vascular endothelial growth fa ctor (VEGF, an index of angiogenesis), hemorheologic factors (plasma viscos ity, hematocrit, white cell count, hemoglobin, platelets), fibrinogen tan i ndex of rheology and hemostasis), and von Willebrand factor (a marker of en dothelial dysfunction) were measured. Results: Median plasma VEGF (225 vs. 195 pg/ml, P = 0.019) and mean von Wil lebrand factor (124 vs. 99 IU/dl, P = 0.0004) were greater in ARMD subjects than the controls. Mean plasma fibrinogen and plasma viscosity levels were also higher in the subjects (both P < 0.0001). There were no significant d ifferences in other indices between cases and controls. When "dry" (drusen, atrophy, n = 28) and "exudative" (n = 50) ARMD subjects were compared, the re was no significant differences in VEGF, fibrinogen, viscosity, or von Wi llebrand factor levels. There were no significant correlations between the measured parameters. Stepwise multiple regression analysis did not demonstr ate any significant clinical predictors (age, gender, smoking, body mass in dex, history of vascular disease, or hypertension) for plasma VEGF or fibri nogen levers, although smoking status was a predictor of plasma von Willebr and factor levels (P < 0.05), Conclusions: This study suggests an association between markers of angiogen esis (VEGF), hemorheologic factors, hemostasis, endothelial dysfunction, an d ARMD, The interaction between abnormal angiogenesis and the components of Virchow's triad for thrombogenesis may in part contribute to the pathogene sis of ARMD. (C) 2001 by the American Academy of Ophthalmology.