EN/DE: Bleeding Disorders / Blutgerinnungsstörung beim Greyhound

[Greyhound-Forum]

BLEEDING DISORDERS IN GREYHOUNDS
By Cheryl Kovaly
April 19, 2016
Greyhounds are predisposed to bleeding disorders. Most adopters are unaware of this and,
unfortunately, the same holds true for many veterinarians. In the past 12 months, three dogs
owned by PG adopters manifested bleeding disorders. Two survived. One did not…a sweet
little two year old girl named Kadin, who we adopted in May of 2015 and lost a mere month
later. Despite the best efforts of three veterinary facilities and eight veterinarians, including Dr.
Cuoto, the nation’s preeminent expert in greyhound bleeding disorders, Kadin did not make it.
In the aftermath of her untimely death, I tried to make some sense of her affliction. After
communicating extensively with Dr. Cuoto and members of the greyhound community
(breeders, trainers, veterinarians and adoption group representatives) and reading a number of
veterinary publications, this is what I learned:
Greyhounds have different blood chemistry than other breeds. Their platelet counts are naturally
low and their red cell counts are naturally high compared to other dog breeds. Platelets are what
cause the blood to clot following an injury or surgery. Because of their naturally low platelet
counts, greyhounds are predisposed to bleeding disorders. Some greyhounds, through genetic
connections that are not fully understood, may have low aminocaproic acid levels in their bodies.
Aminocaproic acid is what holds clots together after they have formed. When a dog with low
platelet counts has low levels of aminocaproic acid, their clots dissolve before they should,
within 12-24 hours after an injury or surgery. The result is that all of the dog's platelets are used
up trying to reform clots at the injury/surgery site. The platelet-depleted blood ultimately thins to
the point that it starts to leak out of the body tissues. The individuals I spoke with who
experienced this condition with their dogs all indicated that there was either a traumatic injury
(an impact injury from a collision or a laceration) or a surgical procedure that started the
bleeding process. Even a simple spay or neuter procedure can trigger the bleeding and, in one
case brought to my attention, the dog experienced a subcutaneous bleeding incident after a
simple blood sample was taken. Any time a greyhound starts to bleed, whether via bruising
from an impact, a bite from another dog, an accidental laceration or a surgical procedure, the risk
of uncontrolled bleeding is present.
In each bleeding disorder case I learned of, the dog came through the original trauma or surgery
just fine, only to start demonstrating uncontrolled bleeding within 3-5 days. Typically, the
bleeding manifested under the skin, in an area apart from the injury or surgery site. Most of
these dogs recovered following administration of supplemental aminocaproic acid.
Unfortunately, some did not. Necropsies performed on the dogs who did not survive revealed the
same condition that Kadin experienced… bleeding from just about all of the body
tissues. Unlike Kadin, whose condition was apparently unique, in that she was bleeding
internally into her abdominal and chest cavities, all of the dogs mentioned in my research had
external signs of bleeding. Typically, the bleeding was subcutaneous, with severe bruising,
discoloration and blood pooling beneath the skin. I have attached photos that were shared with
me by others whose dogs suffered from bleeding disorders. As you can see from the photos, the
severity of the bleeding varied, but all of these dogs may have died had they not received prompt
treatment with Amicar (the brand name for pharmaceutical aminocaproic acid).
My research revealed that greyhound bleeding disorders are not all that uncommon. This
conclusion is supported by the three incidents of bleeding disorders experienced just within the
PG family in the past year. Unfortunately, predisposition to bleeding disorders appears to be
increasing decade by decade, a statistic attributed to the limited number of breeding sires used by
greyhound breeders and the genetic transmittal of this condition. There are certain blood lines
identified as having a higher than ordinary likelihood of producing offspring with bleeding
disorders, including descendants of Brett Lee, Flying Oak, Flying Penske and Dodgem By
Design. That said, bleeding disorders can manifest in any greyhound, of any bloodline.
As previously noted, many general veterinarians are unaware of the predisposition for bleeding
disorders in greyhounds. Of those who have encountered this situation before, most were
unfamiliar with the treatment protocol involving Amicar. This is a "people drug" typically used
in treating individuals with hemophilia or similar bleeding disorders. Aminocaproic acid
supplements what the dog’s own blood is missing and helps to hold clots together. Its use in
greyhounds is not historically well known or documented, other than in several studies
conducted by the Ohio State University Veterinary College involving amputation and neuter
procedures. There are numerous articles available online, published by the Ohio State
vets. They are very technical, and written as veterinary research materials. However, I was also
provided with an article discussing bleeding disorders in deerhounds, which discusses the Ohio
State greyhound studies and publications in layman’s’ terms. It is worth a read and certainly
worth sharing with your veterinarian. You can find this article here:
http://www.iwclubofamerica.org/post-operative-bleeding
One of the Ohio State veterinary publications, which you may wish to print and provide to your
vet, may be accessed via a link embedded in the Deerhound article that is accessible through the
link, above. Additional information for your veterinarian’s consideration may be found at the
following links:
http://www.vet.osu.edu/assets/pdf/hospi ... yDoGreyhou
ndsBleed.pdf
http://www.greyhound-data.com/knowledge ... ote=859728
Greyhound owners need to be aware of the possibility of an uncontrolled bleeding situation
anytime their dog sustains traumatic injury of any type or undergoes a surgical procedure. I can
tell you that there is nothing worse then trying to investigate and find answers and necessary
drugs at a critical moment when your dog’s life hangs in the balance. Aminocaproic acid is not
commonly stocked by pharmacies and can be very hard to find. When we needed it for Kadin,
the Emergency Clinic called 7 pharmacies before they found one that had it in stock. It is very
important to educate your veterinarian early, before there is a potential problem, so that your vet
is aware of the potential for a bleeding condition and has the necessary medication on hand to
treat your dog.
Ultimately, our experience with Kadin was not typical. However, I continue to wonder whether
the outcome would have been different had we been aware of the potential for a bleeding
disorder earlier. Please, take a look at the article on deerhounds, linked above. Discuss this with
your vet. If you are a member of the Yahoo email group, you will know that Cheryl Sterner did
just that and, as a result, her vet had Amicar on hand and was able to administer it to Kaley after
an accidental laceration and stitches led to a subcutaneous bleeding situation. Fortunately, Kaley
is recovering nicely. Hug your hounds!
http://www.pgreys.org/assets/BLEEDING_D ... HOUNDS.pdf

Blutgerinnungsstörungen beim Greyhound
von Cheryl Kovaly, 26.04.2016
(Übersetzungsfreigabe liegt vor!)

Bilder im unten verlinkten Originalpost

Greyhounds haben eine Prädisposition für Blutgerinnungsstörungen.
Die meisten Halter sind sich dessen nicht bewusst und unglücklicherweise sind auch viele Tierärzte darüber nicht informiert.
In den letzten 12 Monaten wurde diese Blutgerinnungsstörung bei 3 Hunden, die über PG adoptiert wurden, festgestellt.
Zwei überlebten. Einer nicht…eine süße zweijährige Hündin namens Kadin, die wir im Mai 2015 adoptierten und nur einen Monat später verloren.
Trotz aller Bemühungen dreier Kliniken und 8 Tierärzten, inklusive Dr. Cuoto, der ein national führender Experte bei Greyhound-Gerinnungsstörungen ist, hat Kadin es nicht überlebt.
Als Folge ihres unerwarteten Ablebens versuche ich dem Ganzen einen Sinn zu geben.
Nach ausgiebigen Gesprächen mit Dr. Cuoto und Mitgliedern der Greyhound Gemeinschaft (Züchter, Trainer, Tierärzte und Mitgliedern von Tierschutzorganisationen) und dem Lesen von einigen tierärztlichen Publikationen, habe ich nun Folgendes zusammengetragen:

Greyhounds haben eine abweichende Blutchemie als andere Rassen.
Die Anzahl der Blutplättchen (Thrombozyten) ist von Natur aus geringer und die Anzahl der roten Blutkörperchen (Erythrozyten) sind von Natur aus höher als bei anderen Hunderassen.
Die Blutplättchen sind für die Gerinnung nach Operationen oder Verletzungen verantwortlich. Aufgrund dessen haben sie eine Prädisposition für das Auftreten von Gerinnungsstörungen.
Manche Greyhounds haben genetisch bedingt eine geringere Konzentration an Aminocapronsäure im Blut. Aminocapronsäure sorgt dafür, dass die Thrombozyten, wenn sie sich verklumpen, zusammengehalten werden und eine stabile Verbindung halten.
Das bedeuted bei einem Hund, der weniger Thrombozyten hat und eine geringere Konzentration an Aminocapronsäure für den Aufbau des Fibrinnetzes, dass innerhalb von 12 bis 24 Stunden die Blutung wieder aufbricht.
In der Folge reagiert der Körper sofort und die restlichen Thrombozyten werden dafür verwendet, diese Verletzung (operativ oder nicht) wieder zu verschließen.
Durch die fehlenden Blutplättchen verdünnt sich das restliche Blut im Körper des Hundes so stark, dass es beginnt durch Körpergewebe hindurch zu sickern.
Die Betroffenen mit denen ich gesprochen habe, erzählten alle, dass ihre Hunde davor entweder ein Unfall-Trauma (Kollision oder Platzwunde) oder einen operativen Eingriff hatten bevor die Probleme auftraten.
Auch eine simple Sterilisation oder Kastration kann diese Blutungen verursachen, in einem Fall war es sogar nur eine Blutabnahme.

Jedes Mal, wenn ein Greyhound blutet, sei es durch eine Prellung durch einen Aufprall, ein Hundebiss, eine Platzwunde oder einen operativen Eingriff, ist das Risiko für unkontrollierte Blutungen präsent.

Bei jedem dieser Blutgerinnungsstörungs-Fälle, schaffte der Hund es durch das ursprüngliche Trauma oder die OP gut. Erst nach 3 bis 5 Tagen wurde diese unkontrollierte Blutung offensichtlich.
Typischerweise manifestierte sich die Blutung unter der Haut, und zwar an einer Stelle, die von der ursprünglichen Trauma- oder OP-Stelle ein Stück entfernt lag.
Die meisten dieser Hunde erholten sich durch das Supplementieren der Aminocapronsäure.
Unglücklicherweise manche auch nicht. Bei der Obduktion dieser Hunde zeigte sich ein ähnlicher Zustand wie bei Kadin…Blutungen aus sämtlichen Körpergeweben.
Anders wie bei Kadin, die in Bauch- und Brusthöhle einblutete, hatten die anderen Hunde alle äußere Anzeichen von Blutungen.
Typischerweise war die Blutung subkutan (unter der Haut), einhergehend mit schweren Prellungen, Verfärbungen und Blutansammlungen unter den Haut.
Ich habe an den Artikel Fotos angehängt, die ich von anderen Haltern zur Verfügung gestellt bekommen habe, deren Hunde ebenfalls Blutgerinnungsstörungen haben.
Wie man auf den Fotos erkennen kann, sind die Einblutungen unterschiedlich schwer ausgeprägt. Aber all diese Hunde hätten sterben können, wenn sie nicht mit Amicar (der Handelsname des Aminocapronsäure-Supplements) behandelt worden wären.

Meine Nachforschungen haben ergeben, dass Blutgerinnungsstörungen bei Greyhounds gar nicht so ungewöhnlich sind.
Dieser Artikel wird auch dadurch gestützt, dass es allein im letzten Jahr 3 Fälle in der PG Familie gab.
Die Inzidenz scheint leider von Dekade zu Dekade zu steigen, was sicherlich auch damit zusammenhängt, dass die Anzahl der Zuchtrüden, die von Züchtern verwendet werden, limitiert ist und damit auch das genetische Material.
Es wurden bestimmte Blutlinien identifiziert, in denen die Wahrscheinlichkeit an Blutgerinnungsstörungen zu leiden und diese zu vererben, deutlich höher liegt. Nachkommen von Brett Lee, Flying Oak, Flying Penske und Dodgem By Design zum Beispiel.
Allerdings kann es auch in anderen Linien bei anderen Greyhounds zu Blutgerinnungsstörungen kommen.

Wie schon zuvor erwähnt, wissen viele Tierärzte über diese Gerinnungsstörungen bei Greyhounds nicht bescheid. Und die, die so eine Situation schon erlebt haben, sind mit dem Behandlungsprotokoll (inkl. Amicar) nicht vertraut.
Amicar ist eigentlich ein Humanpräparat, dass bei Hämophilie oder ähnlichen Gerinnungsstörungen verwendet wird.
Das Medikament supplementiert Aminocapronsäure, die dem Körper des Hundes in dem Moment fehlt und hilft so die Gerinnung aufrecht erhalten zu können.
Der Gebrauch bei Greyhounds ist geschichtlich nicht bekannt oder gut dokumentiert.
Mit Ausnahme von einigen Publikationen bei der Ohio State Universitiy Veterinary College, die auch Amputationen und Kastrationen in diesem Zusammenhang nennt.
Diese sind allerdings sehr technisch geschrieben, weil sie vor allem als tierärztliche Forschungsunterlagen dienen.
Mir wurde jedoch ein Artikel zur Verfügung gestellt, der Gerinnungsstörungen bei Deerhounds diskutierte und auch die Ohio State University Dissertation in Laiensprache mit einbrachte.
Es lohnt sich diesen zu lesen und auf jedem Fall seinem Tierarzt zur Verfügung zu stellen. Hier ist der Artikel zu finden:

http://www.iwclubofamerica.org/post-operative-bleeding

Eine der Ohio State Publikationen, die sich empfiehlt ausgedruckt mit zum Tierarzt zu nehmen, ist oben in dem Artikel verlinkt.
Zusätzliche Informationen, die für die tierärztliche Einschätzung wichtig sein könnten, sind hier in den folgenden Links zu finden:

http://www.vet.osu.edu/assets/pdf/hospi ... sBleed.pdf

http://www.greyhound-data.com/knowledge ... ote=859728

Greyhoundbesitzer sollten um die Gefahr von unkontrollierten Blutungen bei traumatischen Verletzungen oder invasiven Eingriffen, wissen.
Ich kann aus Erfahrung sagen, dass es nichts Schlimmeres gibt, als nach Antworten und notwendigen Medikamenten zu suchen, wenn das Leben des Hundes am seidenen Faden hängt.
Aminocapronsäure ist normalerweise nicht im gängigen Arsenal der Apotheken und kann sehr schwer zu finden sein. Als wir es für Kadin brauchten, musste die Notfall-Klinik sieben Apotheken anrufen, bevor sie eine fanden, die es an Lager hatte.
Es ist sehr wichtig, den Tierarzt rechtzeitig zu informieren bevor es zu einem potenziellen Problem kommt, so dass der Tierarzt im Falle eines Falles die Medikation zur Hand hat.

Letztlich waren die Erfahrungen, die wir mit Kadin machen mussten, nicht typisch.
Trotzdem frage ich mich, ob wir sie hätten retten können, wenn wir um die Problematik früher gewusst hätten.
Bitte schaut Euch den Link mit dem Deerhound-Artikel an, diskutiert mit Eurem Tierarzt.
Wenn Ihr Mitglied in der Yahoo-Email-Gruppe seid, dann wisst Ihr sicher, dass Cheryl Sterner genau das gemacht hatte und als Ergebnis hatte ihr Tierarzt Amicar zur Verfügung und konnte es Kaley verabreichen als sie eine Platzwunde und genäht werden musste, was zu einer subkutanen Blutung führte.
Glücklicherweise erholt sich Kaley hervorragend.
Hug your hounds! (Drückt Eure Hunde!)

Übersetzt von Bettina Kalmbach fürs Greyhound Forum

http://www.pgreys.org/assets/BLEEDING_D ... HOUNDS.pdf

[Greyhound-Forum]

Übersetzung folgt:

Post-Operative Bleeding

Although not commonly seen, there have been reported incidents of unexpected post-operative bleeding in Irish Wolfhounds. The following article by John E. Dillberger, DVM, PhD, Chair of the SDCA Health and Genetics Committee, may be of interest to our breed. It is reprinted with the kind permission of the author and the editor of the Scottish Deerhound Club of America's club publication, The Claymore. The article first appeared in the April 2011 The Claymore.

Post-Operative Bleeding in Greyhounds, and What It Means for Deerhounds

Every few months I hear of another Deerhound that has unexpected bleeding after surgery. The stories are much the same. Dogs typically emerge from surgery in good shape and go home with their owners, only to begin bleeding 24 to 36 hours later. The bleeding doesn’t originate from a single blood vessel; instead, blood seems to seep from every vessel that was cut during surgery. Indeed, the only vessels that don’t bleed are those that were specifically tied off or cauterized during surgery.

Some Deerhounds that have delayed post-operative bleeding survive, but only with heroic and expensive supportive care. Many don’t. Some dogs are simply found dead the morning after surgery.

The recent discovery of an inherited Factor VII gene mutation in Deerhounds led some people to speculate that this might explain the delayed post-operative bleeding. (Factor VII is one of many proteins that help create a blood clot.) Unfortunately, the Factor VII mutation does not explain the problem in Deerhounds. Delayed post-operative bleeding has occurred in dogs with two normal Factor VII genes.

The biggest mystery surrounding delayed post-operative bleeding is also the biggest clue to what may be happening; specifically, the time when bleeding begins. It is as if the Deerhound forms normal blood clots after surgery, but those clots “come unglued” the next day. In other words, the problem is not in the dog’s ability to form a blood clot, but instead in the dog’s ability to maintain the blood clot for a normal length of time.

Another clue that points in the same direction is that some Deerhounds with delayed post­operative bleeding had pre-surgical workups that included tests to evaluate blood clotting function, and the test results were normal. This also suggests that the problem is not in the dog’s ability to form a blood clot.

This mysterious, seemingly random, often fatal problem has led owners to be afraid every time their Deerhound undergoes surgery, or even to forgo elective surgery altogether. Now there is a ray of hope from an unexpected source: retired racing Greyhounds, or more specifically, a group of veterinary researchers at Ohio State University (OSU) who have dedicated themselves to studying that particular dog population.

A few weeks ago, I discovered a paper published in 2008 in the Journal of Veterinary Internal Medicine with the provocative title, “Postoperative Bleeding in Retired Racing Greyhounds.” What particularly caught my attention was that the bleeding in Greyhounds occurred a day or two after surgery.

The lead author, Dr. Ana Lara-Garcia, was on the faculty at OSU when she wrote the paper, but has since moved to England to take a position at the Royal Veterinary College in North Mymms. But the second author—Dr. Guillermo Couto—is still at OSU actively investigating the unique physiology of sighthounds, using racing Greyhounds in the USA and Galgos in Spain as his subjects.

I had a long conversation with Dr. Couto about post-operative bleeding in Greyhounds. Importantly, I learned that OSU had identified an effective drug that can treat the condition if it occurs and that even can be given after surgery to prevent delayed post-operative bleeding.

The Greyhound Story

The published paper describes the results of a study in 88 retired racing Greyhounds (36 males and 52 females) that underwent elective surgery to be neutered at OSU. The paper is so well organized and written that I will simply paraphrase it.

The authors first describe the lines of evidence that led them to study bleeding in Greyhounds:
•There were anecdotal references to excessive bleeding on some Greyhound websites or Greyhound health manuals.
•A web-based survey in 2006, which gathered information on disease prevalence and major causes of death in 747 retired racing Greyhounds, revealed that “bleeding disorders” were one of the four most common causes of death, accounting for 8% of all deaths. In addition, “hematologic diseases” were reported in 3.3% of the dogs, and “spontaneous and postoperative bleeding” accounted for about half of the hematologic disease.
•The authors had observed a tendency for Greyhounds to bleed excessively after minor injuries or simple surgical procedures like neutering or dewclaw removal. Because OSU is a major site for healthcare of retired racing Greyhounds, the authors were in a unique position to notice this tendency to bleed.
•Over a 3-year period at OSU, 10 of 38 Greyhounds that had a limb amputated because of osteosarcoma had severe delayed post-operative bleeding that required intensive care, including blood transfusions, and that resulted in long hospital stays and high medical bills.

From this evidence, the authors developed two theories about Greyhound “bleeders”—either they did not make normal blood clots, or the blood clots they did make were being dissolved too soon.

It may sound odd to you that dogs can dissolve blood clots as well as make them, but clot dissolution actually is an important normal process. The Greyhound story will make more sense if you understand more about how blood clots form and dissolve, so I’ll pause to briefly explain.

How Blood Clots Come and Go

You may not realize it, but blood is poised to clot at any moment. As soon as blood is exposed to damaged tissue or to the air, it starts to clot. This is vitally important to minimize blood loss from an injury. The process of clot formation is called coagulation. Coagulation involves the coordinated activity of circulating cell fragments called platelets, more than a dozen proteins in the blood called coagulation factors (such as Factor VII), and many other proteins that regulate the interactions of these components.

On the other hand, blood must stay in liquid form to circulate freely. If a clot forms in a blood vessel—even a small one—it may cut off the blood supply to a tissue, and the tissue will die within minutes. The result can be fatal, as in the case of a heart attack. That is why dogs (and we) also have a system to quickly dissolve blood clots by a process called fibrinolysis. Fibrinolysis involves the coordinated activity of several different proteins in the blood.

In a normal dog, coagulation and fibrinolysis exist side-by-side in an exquisitely delicate balance. The blood is simultaneously ready to form clots and dissolve clots at a moment’s notice.

The Rest of the Greyhound Story

The OSU researchers did a panel of blood tests before and after surgery to evaluate the coagulation and fibrinolysis systems. They also monitored Greyhounds for post-operative bleeding, scored on a scale of 0 (none) to 4 (severe). Then they compared the blood test results in bleeders and non-bleeders.

None of the 88 Greyhounds bled during surgery or shortly thereafter, but 26% (23 dogs) had delayed post-operative bleeding 36 to 48 hours after surgery! Bleeding was scored as grade 1 in two dogs, grade 2 in 14 dogs, grade 3 in five dogs, and grade 4 in two dogs. Bleeding was confined to the surgical site, never occurring in distant areas. Both findings—that bleeding was delayed and that it was not happening all over the body—suggested that the problem was with clot maintenance, not clot formation.

Coagulation test results were similar in bleeders and non-bleeders, but fibrinolysis test results differed. The fibrinolysis system was more active in bleeders than non-bleeders before surgery.

Taken together the study results suggest very strongly that Greyhound bleeders bled because their fibrinolysis system was turned up high before surgery, so that blood clots dissolved too quickly after surgery. To put it another way, Greyhound bleeders had shifted the balance between coagulation and fibrinolysis more toward fibrinolysis.

But Why?

Why would so many Greyhounds have a tendency for enhanced fibrinolysis, when this could lead to excessive blood loss after an accidental wound or routine surgery? The answer appears to be that humans unintentionally selected for this trait when they created this premier racing and hunting athlete.

Greyhounds differ from other breeds in ways besides the visible ones. Many of the differences are in the cardiovascular system—not just the heart and blood vessels, but also the blood itself.

Greyhound blood has more red blood cells per unit volume, which allows the blood to carry more oxygen but also makes the blood thicker than the blood of other breeds. Greyhounds have larger hearts and thicker arteries than other breeds—large enough not only to cope with thicker blood, but also to pump that blood faster and at higher pressure than in other breeds. All of this is necessary to send enough oxygen to a Greyhound’s massive muscles to produce the explosive acceleration for which the breed was selected over thousands of years.

But there is a price to pay for this sort of high performance circulatory system: blood racing faster and at higher pressures through the vessels produces more damage to the vessel walls.

Blood vessels are lined by a thin layer of cells called endothelial cells. Like roof shingles in a high wind, these cells regularly shear off, exposing the tissue beneath. The exposed tissue triggers a tiny blood clot to form. This micro-clot covers the gap and gives the adjacent endothelial cells time to repair the damage, both by spreading themselves more thinly and by dividing to make new endothelial cells.

Each time a micro-clot forms, there is a risk that the blood clotting process will get out of control and make a clot so big that it blocks the blood vessel, or even trigger blood clots to form throughout the blood stream. That’s where the fibrinolysis system comes into play, to make sure the micro-clot forms only where it’s needed and that it stays intact only as long as necessary.

Because Greyhound blood is thicker and moving faster, Greyhounds experience more endothelial cell damage and form more micro-clots than other breeds. This, in turn, can put their fibrinolysis system into high gear. And this shifts the balance more toward clot dissolution than clot formation.

What This Means for Deerhounds

Honestly, I think that you could substitute the word Deerhound for Greyhound throughout this article. The delayed post-operative bleeding that has occurred in many Deerhounds seems identical in every respect to what is described in Greyhounds. And that actually makes a lot of sense.

The most important point in the Deerhound standard is that “a Deerhound should resemble a rough-coated Greyhound of larger size and bone.” As it happens, Deerhounds do not just look like Greyhounds on the outside; they also work like Greyhounds on the inside.

Like Greyhounds, Deerhounds have thick blood moving at high speed and under high pressure, and consequently have more frequent blood vessel damage and micro-clot formation. As a consequence many Deerhounds almost certainly have fibrinolysis systems that are hyperactive, putting them at risk for delayed post-operative bleeding.

The OSU authors also speculated that the situation in Greyhounds probably existed in other sighthounds. They put it like this (with italics added by me):

“The [state of enhanced fibrinolysis] in retired racing Greyhounds could be an adaptational mechanism to racing or an evolutionary trait designed to prevent clotting of blood with high viscosity... that circulates through large muscle masses, as has been reported in human athletes... [and] in transgenic mice [with high viscosity blood]. ...It is very tempting to think that a similar phenomenon may occur in [all] sight hounds and that they have evolved to be “hypocoagulable” in order to prevent intravascular thrombosis during strenuous exercise.”

What Can You Do?

There are clinical situations in which enhanced fibrinolysis occurs in humans, leading to an increased risk of bleeding. In such situations, patients are treated with the drug aminocaproic acid (Amicar®), which inhibits fibrinolysis.

Researchers at OSU have just finished a clinical trial in 100 Greyhounds undergoing spay or neutering surgery, to see if aminocaproic acid would reduce or prevent delayed post-operative bleeding. The results are not yet published, so I cannot share them with you. But I can tell you that the results led OSU to change its standard surgical protocol so that every Greyhound is now given aminocaproic acid for 5 days after surgery. The aminocaproic acid dose for a 30-kg (66-lb) Greyhound is 500 mg every 8 hours, which is about 17 mg/kg (8 mg/lb).

I think we should adopt the same approach for Deerhounds that OSU has taken for Greyhounds. Every Deerhound that undergoes elective surgery should be given aminocaproic acid for the next 5 days to reduce the risk of delayed post-operative bleeding. Aminocaproic acid is available in 500-mg scored tablets. The dose should be as follows:


Aminocaproic Acid Dose for Deerhounds


Dog weight

Dose every 8 hours

55 to 79 lbs 500 mg (1 tablet)
80 to 104 lbs 750 mg (1 1/2 tablet)
≥ 105 lbs 1000 mg (2 tablets)

I do not make this recommendation lightly. Every drug carries the risk of side effects, and aminocaproic acid has not been studied in Deerhounds. However, aminocaproic acid has been studied in Greyhounds in a controlled clinical trial, which is more than can be said for many of the drugs we use routinely in Deerhounds. More importantly, the veterinary researchers at OSU concluded that the benefits of aminocaproic acid in preventing life-threatening delayed post­operative bleeding far outweighed the risk of potential side effects.

Amicar® was approved for human use in 1964, at a time when relatively little animal testing was done with human drugs. It is available as an injectable liquid and as pills. The product label contains two references to potential side effects in dogs, but only when the drug is given intravenously:
•“Fatty degeneration of the myocardium has been reported in dogs given intravenous doses of aminocaproic acid at 0.8 to 3.3 times the maximum human therapeutic dose.” The maximum human dose is about 32 mg/lb, so the dose range reported to cause fatty degeneration of the heart in dogs is about 26 to 107 mg/lb. This is approximately 3 to 13 times the dose recommended to prevent delayed post-operative bleeding (8 mg/lb).
•An intravenous... dose of 2,300 mg/kg was lethal in the dog.” This is about 1,045 mg/lb, or approximately 130 times the dose recommended to prevent delayed post-operative bleeding.

When the OSU clinical trial results are published, we will have a better idea of the incidence and nature of side effects in dogs given Amicar® by mouth. I will share this information as soon as it is available.

Thanks to studies in retired racing Greyhounds, I believe we finally have a likely explanation for the delayed post-operative bleeding that has occurred in many Deerhounds. Better yet, there is a readily available drug that offers the promise of preventing the condition and saving Deerhound lives. For my part, I will not put another of my Deerhounds through surgery without giving aminocaproic acid for 5 days afterwards to reduce the risk of delayed post-operative bleeding. I urge you to consider doing the same.

Dr. John E. Dillberger, P.O. Box 2118, Nashville, IN 47448-2118 (812) 988-6175

Click here to read Dr. Dillberger's 2014 follow-up article.

https://www.iwclubofamerica.org/post-operative-bleeding