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Laboratory measures of hemostasis and fibrinolysis after intravenous administration of ϵ-aminocaproic acid in clinically normal horses and ponies

Peter Heidmann DVM, MPH1,2, Susan J. Tornquist DVM, PhD3, Annie Qu PhD4, and Christopher K. Cebra VMD, MS5
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  • 1 Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4803.
  • | 2 Present address is Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 3 Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4803.
  • | 4 Department of Statistics, Oregon State University, Corvallis, OR 97331-4803.
  • | 5 Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4803.

Abstract

Objective—To determine whether ϵ-aminocaproic acid (EACA) administered IV affects hemostasis and fibrinolysis in clinically normal horses and ponies.

Animals—20 clinically normal adult horses and ponies.

Procedures—Blood samples were collected 24 hours before (baseline) and 1 and 5 hours after IV administration of a low dose (30 mg/kg) or high dose (100 mg/kg) of EACA. Platelet count, fibrinogen concentration, prothrombin time, partial thromboplastin time (PTT), D-dimer concentration, α2-antiplasmin activity, and thrombin-antithrombin complex concentration were measured. Values at 1 and 5 hours were compared with baseline values.

Results—1 hour after administration of a low dose of EACA, mean fibrinogen concentration was significantly lower than baseline concentration. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a low dose of EACA. One hour after administration of 100 mg of EACA/kg, mean α2-antiplasmin activity was significantly higher than baseline activity. Mean fibrinogen concentration was significantly lower than baseline concentration 1 and 5 hours after administration of a high dose of EACA. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a high dose of EACA.

Conclusions and Clinical Relevance—IV administration of 30 and 100mg of EACA/kg to clinically normal horses significantly modified some laboratory measures of hemostasis, consistent with its known antifibrinolytic effects. Although enhanced clot maintenance and diminished bleeding were not directly assessed, the clinical use of EACA may benefit some patients. ( Am J Vet Res 2005;66:313–318)

Abstract

Objective—To determine whether ϵ-aminocaproic acid (EACA) administered IV affects hemostasis and fibrinolysis in clinically normal horses and ponies.

Animals—20 clinically normal adult horses and ponies.

Procedures—Blood samples were collected 24 hours before (baseline) and 1 and 5 hours after IV administration of a low dose (30 mg/kg) or high dose (100 mg/kg) of EACA. Platelet count, fibrinogen concentration, prothrombin time, partial thromboplastin time (PTT), D-dimer concentration, α2-antiplasmin activity, and thrombin-antithrombin complex concentration were measured. Values at 1 and 5 hours were compared with baseline values.

Results—1 hour after administration of a low dose of EACA, mean fibrinogen concentration was significantly lower than baseline concentration. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a low dose of EACA. One hour after administration of 100 mg of EACA/kg, mean α2-antiplasmin activity was significantly higher than baseline activity. Mean fibrinogen concentration was significantly lower than baseline concentration 1 and 5 hours after administration of a high dose of EACA. Mean PTT was significantly shorter than the baseline value 5 hours after administration of a high dose of EACA.

Conclusions and Clinical Relevance—IV administration of 30 and 100mg of EACA/kg to clinically normal horses significantly modified some laboratory measures of hemostasis, consistent with its known antifibrinolytic effects. Although enhanced clot maintenance and diminished bleeding were not directly assessed, the clinical use of EACA may benefit some patients. ( Am J Vet Res 2005;66:313–318)