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T Yamamoto, M Kamei, N Yokoi, K Mori, T Yasuhara, M Tei, S Kinoshita; Spontaneous Platelet Aggregation and Antiplatelet Therapy in Retinal Vein Occlusion . Invest. Ophthalmol. Vis. Sci. 2002;43(13):513.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:.Platelets can play an important role in the pathogenesis of retinal vein occlusion (RVO), but the mechanism is not completely understood. We quantified platelet aggregates in RVO with a novel platelet aggregometer, using light scattering. This method can quantify platelet aggregates formed in the absence of chemical stimulants (spontaneous platelet aggregation; SPA), which cannot be done using the optical density method. We also compared the effects of three antiplatelet medications. Methods:(1) SPA was measured in 22 patients with untreated branch RVO (BRVO), 20 with central RVO (CRVO), and 26 healthy volunteers (control), with a light-scattering platelet aggregometer (PA200, Kowa, Japan). Platelet aggregates were classified into three sizes according to light intensity: small (25-400), medium (400-1000), and large (1000-2048). Total light intensities of each aggregate size were compared among the 3 groups (Fisher’s PLSD). (2) In the 22 patients with untreated RVO (13 BRVO, 9 CRVO), SPA was compared between before and 2 weeks after administration of one of the following antiplatelet medications: ticlopidine (100mg/day), beraprost (40µg/day), and aspirin (100mg/day) (Wilcoxon signed-ranks test). Results:(1) BRVO showed significant increase in small aggregates (p = 0.04), while CRVO showed significant increase in small (p < 0.001) and medium (p = 0.03) aggregates as compared with control. (2) Ticlopidine did not significantly inhibit any size aggregates. Beraprost significantly inhibited all size aggregates (p < 0.05). Aspirin significantly inhibited only large aggregates (p < 0.05). Conclusion:Increased platelet aggregation has been demonstrated in RVO. Increase in small aggregates may be attributable to RVO pathogenesis. Beraprost is considered the most effectual antiplatelet medicine. The light-scattering method is useful for investigating the pathogenesis of RVO and antiplatelet medication effect.
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