WSAVA Nov 2021 Proceedings - Flipbook - Page 26
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7. Lynch, A.M., et al. Clinical experience of anti-Xa monitoring in critically
ill dogs receiving dalteparin. J Vet Emerg Crit Care 24, 421-428 (2014).
8. Goggs, R., et al. CURATIVE: Domain 2-Defining rational therapeutic
usage. J Vet Emerg Crit Care 29, 49-59 (2019).
9. Brainard, B.M., et al. CURATIVE: Domain 5-Discontinuation of anticoagulant therapy in small animals. J Vet Emerg Crit Care 29, 88-97 (2019)
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ANTIFIBRINOLYTICS – WHAT IS THE EVIDENCE?
C. Sharp
Murdoch/Australia
Qualifications:
Dr Claire R. Sharp
BSc, BVMS(Hons), MS, DACVECC
c.sharp@murdoch.edu.au
Fibrinolysis
The goal of the coagulation cascade is the formation of a stable fibrin
clot to achieve hemostasis. Fibrinolysis (Figure 1) is the process of
removal of intravascular fibrin clots; in health this should occur after the
clot is no longer needed. Fibrinolytic disorders result from a disturbance
in the balance of fibrinolytic activators and inhibitors, and are becoming
increasingly recognized in veterinary medicine. This discussion will focus
on hyperfibrinolysis and the use of antifibrinolytics to treat associated
bleeding.
Diagnostic approach to disorders of fibrinolysis
Assessment of fibrinolysis may be indicated in patients with inappropriate
bleeding that cannot be explained by disorders of primary or secondary
hemostasis. Fibrinolysis may be assessed with measurement of FDPs,
D-dimers, and viscoelastic tests (thromboelastography [TEG], rotational
thromboelastometry [ROTEM]), however all have significant limitations.
Antifibrinolytic drugs
Lysine analogs are the mainstay treatments for hyperfibrinolysis. These
drugs reversibly block the lysine binding site of plasminogen, preventing
its activation to plasmin. The two commercially available lysine analogs
are tranexamic acid (TXA) and epsilon-aminocaproic acid (EACA), in both
IV and PO formulations. Availability does vary from country to country.
EACA is less potent than TXA. Reported doses vary considerably in dogs
from 15-40mg/kg IV as a loading dose, followed by 500-1000mg PO q8h
for 5 days. Other authors have used a dose of 50-100mg IV or PO q6-8h.
Adverse effects include nausea, vomiting, abdominal pain, and diarrhoea.
TXA is more potent and has a longer half-life than EACA. The ideal dosing
regimen of TXA in dogs is not known but the author doses at 15mg/kg
IV q 8 hours (diluted, slow IV) during the perioperative period for dogs at
risk of, or with documented, hyperfibrinolysis. Some authors use 10mg/
kg as an IV bolus, followed by CRI of 10mg/kg/hr for three hours.(1)
Adverse effects of TXA include gastrointestinal (2,3), anaphylaxis (4), and
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