title: Effects of clopidogrel therapy on whole blood platelet aggregation, the Plateletworks® assay and coagulation parameters in cats with asymptomatic hypertrophic cardiomyopathy: a pilot study.
abstract: BACKGROUND
  Although scientific evidence is limited, clopidogrel is frequently used as prophylaxis for arterial thromboembolism in cats with hypertrophic cardiomyopathy (HCM).
  
  
  OBJECTIVE
  Evaluating effects of clopidogrel therapy in asymptomatic cats with HCM on (1) conventional whole blood aggregation (WBA), (2) alternative platelet aggregation assessed with tubes of the Plateletworks® assay and (3) standard coagulation parameters.
  
  
  METHODS
  Prospective, randomized, double-blind, placebo-controlled pilot study. Fourteen asymptomatic HCM cats were randomly allocated to receive placebo (n = 5) or clopidogrel (18.75 mg/cat q24h, n = 9) as part of a larger study. Aggregation responses (to 20 µM adenosine diphosphate (ADP) and 10 µg/ml collagen) in WBA and the Plateletworks® assay and standard coagulation parameters were evaluated at baseline and after seven days of therapy.
  
  
  RESULTS
  Clopidogrel therapy significantly reduced aggregation responses to ADP and collagen in the Plateletworks® agonists tubes (ADP and collagen: P < 0.001), but did not significantly reduce aggregation responses to ADP and collagen in the WBA technique (ADP: P = 0.07, collagen: P = 0.30). Clopidogrel therapy did not show a significant effect on prothrombin time, activated partial thromboplastin time, antithrombin, D-dimers and fibrinogen concentrations.
  
  
  CONCLUSIONS
  Clopidogrel therapy at a dose of 18.75 mg/cat q24h for seven days causes a significant decrease in in vitro platelet aggregation evaluated with the Plateletworks® assay, without affecting standard coagulation parameters in cats with asymptomatic HCM.
authors: a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands.
authors: M L
authors: ML
authors: den Toom
authors: a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands.
authors: M W
authors: MW
authors: van Leeuwen
authors: a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands.
authors: V
authors: V
authors: Szatmári
authors: a Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands.
authors: E
authors: E
authors: Teske
mesh_terms: D000244:Adenosine Diphosphate / Q000008:administration & dosage; D000818:Animals; D058070:Asymptomatic Diseases / Q000628:therapy; D001777:Blood Coagulation / Q000187:drug effects*; D002312:Cardiomyopathy, Hypertrophic / Q000188:drug therapy / Q000209:etiology / Q000662:veterinary*; D002371:Cat Diseases / Q000188:drug therapy* / Q000209:etiology; D002415:Cats; D000077144:Clopidogrel; D004311:Double-Blind Method; D005260:Female; D008297:Male; D010865:Pilot Projects; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D011446:Prospective Studies; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000244:Adenosine Diphosphate; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: Cat; arterial thromboembolism; cardiomyopathy; clopidogrel, platelet; feline