Delayed Post-operative Hemorrhage (DEPOH), sometimes also called Delayed Bleeding Syndrome or hyperfibrinolysis, occurs when a hound has one or two copies of a variant form of a gene that is involved in preventing blood clots from dissolving until after a wound has healed. This condition is found in several breeds, including Irish Wolfhounds, Deerhounds, and some mixed-breed dogs. The disease can affect dogs of either sex.
Irish Wolfhounds can die after surgery, not immediately, but one or more days afterward. More than one owner has informed me that their wolfhound had most likely "bled out," -- internal bleeding -- as this is what their veterinarians had suspected. This can be prevented!
The Scottish Deerhound Association Health & Genetics website has valuable information on Post-Operative Bleeding in Greyhounds and what it may mean for Deerhounds. It is also located on the Irish Wolfhound Club of America website, albeit in a hard-to-find area.
Sighthound (greyhound-like) breeds are unique and unprecedented, and this is not just my considered supposition but also the authors of an Ohio State University research committee. In a paper published in 2008, the OSU authors also speculated that the situation in Greyhounds probably existed in other sighthounds.
The Scottish Deerhound Club of America Health Issues webpage states the following, which portions I have extracted
When a blood clot forms to stop a wound from bleeding, the clot normally is dissolved after the wound heals. A normal DEPOH gene contains instructions for making a protein that prevents blood clots from dissolving. But the protein made by the variant form of the gene does not work as efficiently as that made by the normal form of the gene. As a result, blood clots in Deerhounds with DEPOH can dissolve prematurely after major surgery or trauma. Problems, including severe skin bruising and bleeding from the wound, are typically first noticed one or two days after surgery or injury, but have been seen as early as right after surgery.
The variant causing DEPOH is inherited as a dominant gene with incomplete penetrance, so dogs are either clear (no copies of the mutation) or affected (having one or two copies of the gene). Current research shows that, compared to a clear dog, a dog with one copy of the DEPOH variant is 28 times more likely to experience delayed bleeding, while a dog with two copies is 1235 times more likely to experience delayed bleeding.
Dogs that have one or two copies of the DEPOH variant have no problems day-to-day and lead normal lives, but they have a higher risk of bleeding after surgery or trauma. For reasons not yet understood, affected dogs (especially dogs with only one copy of the DEPOH variant) can undergo surgery without experiencing delayed bleeding problems. But if delayed bleeding does occur, it can be fatal, particularly if it isn’t caught soon after it starts.
Most bleeding starts within 24–48 hours after surgery, although there are cases where it starts earlier. There is no way to predict how an individual DEPOH-affected dog will react during or after major surgery. Bleeding can be prevented and/or treated with the administration of aminocaproic acid (also known by its brand name, Amicar) or tranexamic acid.
If using Amicar, the first dose is given via IV slowly, and subsequent doses are given every 8 hours orally if the dog can take meds that way. Treatment usually continues for five days. Alternatively, for elective surgeries, one of these drugs should be given prophylactically to dogs beginning the day of surgery, three to one hour before the procedure, and then three times daily for five days. Please note: most veterinary clinics do not stock either of these two medications, so owners of dogs with one or two copies of the DEPOH mutation or whose dogs’ DEPOH status isn’t known are encouraged to keep an up-to-date supply.
Epsilon Aminocaproic Acid (Amicar®) or Tranexamic Acid Doses
Dosages for these drugs can be found here.
There may be a risk of thrombosis if given to unaffected individuals. {DISCLAIMER: To date, my hounds have been prescribed Amicar by the Theriogeneologist as standard practice without our having definitive knowledge that my hounds carried the mutation. Nonetheless, the Reproductive Specialists did not want to chance it, so we administered it, and today it is a standard practice, and I have not had any hounds present side effects on either Acid.}
Dogs that have a bleeding episode post-operatively or after major trauma should be treated immediately with either aminocaproic acid or tranexamic acid, the first dose given IV slowly, if possible (if not, give the drug orally), and subsequent doses given every 8 hours orally if the dog can take meds that way. Treatment usually continues for five days.
Amicar or Tranexamic Acid may prove to be a lifesaver for your sighthound after elective surgery. The stories are the same in Wolfhounds, Deerhounds, and Greyhounds.
Both Aminocaproic Acid (Amicar) and Tranexamic Acid are absolutely critical for any major surgery on an Irish Wolfhound. The important difference between the two is availability. Amicar has a very short shelf life and must be compounded for the pet owner to administer to their hound orally via liquid or capsule. This can take at least one week minimum to manufacture and ship, which, in an emergency, renders it useless.
The Tranexamic Acid can be obtained with a prescription at the local pharmacy. Call the pharmacy first to confirm, but I have not had any issues with my local pharmacy. The veterinarian can prescribe the drug for you.
When to use which acid?
The following presentation was given at the SDCA 2021 National Specialty in Richland, Washington. Keep in mind this researcher speaks of mutant and or normal hounds, he is referring to the Deerhounds who have undergone genetic testing for the mutation. However, though the IW Foundation does not have a study in progress on post-operative bleeding, they did sample blood from various wolfhounds (one of them being mine) and discovered that one or more of my Wolfhounds had the SERPINF2 mutation for delayed postoperative bleeding.
The Scottish Deerhound Club of America Health Issues webpage with Dr. Michael H. Court, a researcher at the Pharmacogenomics Laboratory in the College of Veterinary Medicine at Washington State University, presented the following:
For whelping – Based on the cases that have been referred to me, the bleeding risk after whelping is much less than 00the risk for C-section. I know of 2 mutant/mutant dogs that had unusually long bloody discharge after whelping, but nothing requiring treatment. I don’t expect a problem with heterozygotes (mutant/normal). Regardless, I think it is a good idea to have oral Amicar or tranexamic acid on hand for mutant/normal and mutant/mutant dogs to give if the bleeding seems excessive.
For C-section – For mutant/mutant dogs, the current recommendation for surgery is prophylactic treatment. The drugs should be started before surgery. Since a C-section is often unplanned and time is important, IV administration (dilute 1:3 in saline and give over 20 minutes) starting about 1 hour before surgery is recommended, followed by oral dosing every 8 hours for 5 days. Consider using tranexamic acid (20 mg/kg) instead of Amicar if it is available.
For heterozygous (mutant/normal) dogs, the current recommendation for surgery—including C-section—is to have Amicar or tranexamic acid available to give during or after surgery if bleeding seems excessive. But it depends on where a breeder is on the risk/benefit equation; if very concerned, then the breeder should go ahead with prophylactic treatment (as described for mutant/mutant dogs).
One caveat regarding treating C-section dogs routinely is the potential risk to the pups from the drug getting into the milk. The only information we have is for breastfeeding women. For Amicar, there is a warning on the drug label to “exercise caution” in breastfeeding women, but there is no evidence that it can get into the milk and cause problems. For tranexamic acid, the warning is similar. However, there is some evidence that the amount that gets into the milk is 100x less than what is in the mother’s blood. There is also one (admittedly small) study in breastfeeding women taking tranexamic acid that showed no adverse effects in their children. So—theoretically—tranexamic acid might be a better choice than Amicar.
So—for me—the bottom line is:
For whelping, it is not necessary to give Amicar or tranexamic acid, but do have it on hand (to be cautious).
For C-section – mutant/mutant dogs should receive prophylactic treatment. For heterozygous (mutant/normal) dogs, it depends on where you are on the risk/benefit equation. If a breeder is very concerned, then they should go ahead with prophylactic treatment. But at the very least, they should have Amicar or tranexamic acid on hand to give during or after surgery if bleeding seems excessive.