With the increasing popularity of retired racing Greyhounds and other sighthounds as pets, veterinarians are likely to evaluate dogs of these breeds more frequently in their practice. Therefore, it is important that they recognize the physiological peculiarities of Greyhounds and other sighthounds. Spontaneous or delayed postoperative bleeding is one of them; it has been documented in Greyhounds, Deerhounds, Irish Wolfhounds, and I have seen it in other sighthounds.
In the Greyhound community, the term “Greyhound bleeder” is typically used for dogs that bleed either spontaneously or 1-2 days after minor trauma or a simple surgical procedure. This can result in severe bleeding after routine major or minor surgical procedures, lacerations, tooth extractions, biopsies, blood draws, and even microchip placement.
We worked on hemostasis (clotting) in Greyhounds for over a decade, and determined that approximately 25% of retired racers will bleed 36-48 hours after a spay or neuter procedure; despite this, all the tests of hemostasis (clotting) are normal, and they do not differ between bleeders and non-bleeders. Recent work at Washington State University confirmed that, as we proposed in 2008, this is due to hyperfibrinolysis (the clot-busting system kicking into overdrive), and they developed a genetic test (DEPOHGEN) in Deerhounds.
Disseminated Intravascular Coagulation in Greyhounds
The bleeding typically starts around the surgical site, and may become extensive and generalized. When confronted with a dog with disseminated bleeding, most veterinarians tend to diagnose them as disseminated intravascular coagulation (DIC) a serious, and oftentimes fatal syndrome of simultaneous clotting and bleeding. We have conclusively excluded DIC as a mechanism of bleeding in sighthounds.
In normal dogs and people, the strength of a clot increases 24-48 hours after trauma of surgery, since effective clotting is the first step in healing (scarring). Our studies revealed that Greyhound “bleeders” are not able to increase the clot strength after surgery, as the “non-bleeders” and other non-Greyhound dogs do. As of now, there are no tests that can predict the potential for bleeding before surgery, except for the DEPOHGEN test in Deerhounds; this test has not yet been validated in other sighthound breeds.
Decreasing Bleeding Severity
We extensively evaluated a pro-coagulant (epsilon aminocaproic acid-EACA or Amicar®), at dosages of 500-1,000 mg, orally or intravenously, every 8 hours, for 5 days, starting the day of or the day after the surgery. This drug significantly decreases the severity and frequency of bleeding in Greyhounds undergoing limb amputation for bone cancer, after spays/neuters, and other surgeries. It is also effective in dogs who bleed due to lacerations, dental extractions, etc. If EACA is not available, tranexamic acid (650-1,000 mg, PO, q8h) can be used.
| PREVENTION OR TREATMENT OF SPONTANEOUS BLEEDING IN GREYHOUNDS Aminocaproic acid or tranexamic acid, 500-1,000 mg, orally, 3 times a day for 5 days, starting the day of the surgery or the bleeding. |
We also worked on the issue of thrombosis (clot formation) and thromboembolism (clot formation and migration) in Greyhounds. We recognized aortic, iliac, or femoral thrombosis as a cause of intermittent rear leg lameness in Greyhounds, and also identified the fact that retired racers are at high risk for brain or spinal cord thromboembolic events. The latter are acute, and cause severe neurologic signs (incoordination, paralysis, inability to move, excessive salivation, abnormal eye movement, etc). Mini-dose aspirin (1/4-1/2 of an 81 mg cardio aspirin once a day) results in rapid, marked clinical improvement in these patients. We evaluated another drugs (Plavix), but in our hands it was not very effective in Greyhounds (however, it works well in non-Greyhound breeds and in cats).
| PREVENTION OR TREATMENT OF SPONTANEOUS THROMBOSIS (CLOTS) IN GREYHOUNDS: Aspirin ½ to 1-81 mg tablets, orally, once a day. |
References
Court, M. H., Kiser, J. N., Neibergs, H. L., Zhu, Z. & Dillberger, J. E. Identification by whole genome sequencing of genes associated with delayed postoperative hemorrhage in Scottish deerhounds. J Vet Intern Med (2023) doi:10.1111/jvim.16643.
Lara García A, Couto CG, Iazbik MC, Brooks M: Postoperative bleeding in retired racing Greyhounds. J Vet Intern Med 2008; 22:525-533.
Lord L, Yaissle J, Marin L, Couto CG: Results of a web-based health survey in retired racing Greyhounds. J Vet Intern Med 2007;21:1243-1250.
Marín LM, Couto CG, Iazbik MC, Westendorf N, Vilar Saavedra P: Effects of time of collection and sample processing on von Willebrand factor concentration in Greyhounds.J Vet Intern Med 2008; 22:1447-1448.
Marin LM, Iazbik MC, Zaldivar-Lopez S, Guillamin J, McLoughlin MA, Couto CG. Epsilon Aminocaproic Acid for the Prevention of Delayed Postoperative Bleeding in Retired Racing Greyhounds Undergoing Gonadectomy. Veterinary Surgery 2012;41:594–603.
Marin LM, Iazbik MC, Zaldivar-Lopez S, Westendorf Stingle N, Hudson D, Vilar P, Lara A, Alvarez F, HosoyaK, NelsonL, PozziA, Cooper E, McLoughlin MA, BallR, Kisseberth W, London C, Dudley R, Dyce J, McMahon M, Lerche P, Bednarski R, Couto CG. Retrospective evaluation of the effectiveness of epsilon aminocaproic acid for the prevention of postamputation bleeding in retired racing Greyhounds with appendicular bone tumors: 46 cases (2003-2008). Journal of Veterinary Emergency and Critical Care 2012;22:332–340.
Vilar Saavedra P, Couto CG, Iazbik, MC, Westendorf N, Charske J, Marín LM. Thromboelastographic tracings in retired racing Greyhounds and in non-Greyhound dogs. J Vet Intern Med 2008; 22:374–379.