Effects of intravenous aminocaproic acid on exercise-induced pulmonary haemorrhage (EIPH).
BACKGROUND
The antifibrinolytic, 6-aminohexanoic acid, also named aminocaproic acid (ACA), has been used empirically as a treatment for exercise-induced pulmonary haemorrhage (EIPH) on the unsubstantiated basis that transient coagulation dysfunction may contribute to its development.


OBJECTIVE
To assess the effect of ACA on bronchoalveolar lavage fluid (BALF) erythrocyte counts in horses performing treadmill exercise at an intensity greater than that needed to reach maximal oxygen consumption.


METHODS
Eight Thoroughbreds were exercised to fatigue 3 times on a 10% inclined treadmill at a speed for which the calculated oxygen requirement was 1.15 times VO2max. Horses were treated with a saline placebo, 2 and 7 g ACA i.v. 4 h before exercise, with a crossover design being used to determine the order of the injections. Exercise-induced pulmonary haemorrhage severity was quantified via the erythrocyte count in BALF. Bronchoalveolar lavage fluid was collected 4 h before and 30-60 min post exercise. Results were expressed as mean ± s.e.m. and analysed by one way repeated measures ANOVA (P < 0.05).


RESULTS
Aminocaproic acid administration had no effect on any measured variables (VO2max = 48 ± 3.0 [C]; 148 ± 3.0 [2 g ACA]; 145 ± 3.0 [7 g ACA] ml/kg bwt/min, respectively; run time = 77 ± 3 [C]; 75 ± 2 [2 g ACA]; 79 ± 3 [7 g ACA] seconds, respectively). All horses developed EIPH: 1691 ± 690 vs. 9637 ± 3923 (C); 2149 ± 935 vs. 3378 ± 893 (2 g ACA); 1058 ± 340 vs. 4533 ± 791 (7 g ACA) erythrocytes/µl pre- vs. post exercise recovered in BALF, respectively.


CONCLUSIONS
Aminocaproic acid was not effective in preventing or reducing the severity of EIPH or improving performance under the exercise conditions of this study.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, USA. bbuchholz@vetmed.wsu.edu
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Sides
D000614:Aminocaproates / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D000933:Antifibrinolytic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006470:Hemorrhage / Q000188:drug therapy / Q000662:veterinary*; D006734:Horse Diseases / Q000188:drug therapy* / Q000209:etiology; D006736:Horses; D008171:Lung Diseases / Q000188:drug therapy / Q000662:veterinary*; D008297:Male; D010805:Physical Conditioning, Animal / Q000009:adverse effects*
D000614:Aminocaproates; D000933:Antifibrinolytic Agents