title: Comparative effect of antiplatelet therapy in retinal vein occlusion evaluated by the particle-counting method using light scattering.
abstract: OBJECTIVE
  To evaluate platelet aggregation in patients with retinal vein occlusion (RVO) by the light-scattering method and compare the effects of three antiplatelet drugs on aggregate formation.
  
  
  METHODS
  Prospective, nonrandomized, interventional clinical trial.
  
  
  METHODS
  (1) Platelet aggregation was measured in 42 patients with untreated branch RVO (BRVO), 26 patients with central RVO (CRVO), and 30 healthy control subjects using a light-scattering platelet aggregometer. Platelet aggregates were classified as small, medium, and large according to light intensity. Total light intensities of each aggregate size were compared between BRVO, CRVO, and control subjects. (2) In 33 patients with RVO, platelet aggregation before and 2 weeks after the administration of ticlopidine, beraprost, or aspirin were compared.
  
  
  RESULTS
  (1) There was a statistically significant difference (P = 0.0073) between the control subjects (8.3 x 10(6) a.u.) and CRVO patients (22.9 x 10(6) a.u.) with respect to small aggregates. There was no statistically significant difference with respect to medium and large aggregate formation between the control subjects and either patient group. (2) Compared with aggregates formed in the absence of antiplatelet drugs, ticlopidine significantly inhibited only the formation of small aggregates and beraprost that of all sizes; aspirin did not significantly inhibit the formation of any aggregate sizes.
  
  
  CONCLUSIONS
  Increase in small platelet aggregates may be attributable to RVO pathogenesis. Beraprost and ticlopidine appear to inhibit small aggregate formation in RVO patients and may represent effective antiplatelet treatments. The light-scattering method is useful to investigate the pathogenesis of RVO and the effects of antiplatelet drugs.
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan. tymamot@ophth.kpu-m.ac.jp
authors.forename: Takami
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Motohiro
authors.initials: M
authors.lastname: Kamei
authors.forename: Norihiko
authors.initials: N
authors.lastname: Yokoi
authors.forename: Toru
authors.initials: T
authors.lastname: Yasuhara
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tei
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kinoshita
mesh_terms: D000368:Aged; D001241:Aspirin / Q000627:therapeutic use*; D011464:Epoprostenol / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D010979:Platelet Function Tests; D011446:Prospective Studies; D012170:Retinal Vein Occlusion / Q000188:drug therapy*; D012542:Scattering, Radiation; D013988:Ticlopidine / Q000627:therapeutic use*
chemical_list: D010975:Platelet Aggregation Inhibitors; C048081:beraprost; D011464:Epoprostenol; D013988:Ticlopidine; D001241:Aspirin