One of the events animal rescuers happily anticipate is making a follow-up call after an adoption to find out how the lucky pooch is adjusting. When the family’s response is positive–as it usually is–the rewards are priceless. However, sometimes post-adoption news is heartbreaking. I discovered such was the case when I called about an adopted black Lab and learned he had developed an aortic thromboembolism.
Definition
An aortic thromboembolism in dogs is sometimes called a saddle thrombus, according to PetMD. It’s basically a blood clot in the heart. While fairly uncommon in dogs, it’s much more prevalent in cats.
The condition arises when a blood clot gets thrown into the aorta, the biggest artery in the body. This event blocks the flow of blood to any tissues in the dog’s body linked to that section of the artery. Rural Area Veterinary Services expert Bob McKee states that most of these clots form in the left atrium, then move through the left ventricle to reach the aorta. Once a clot reaches the circulatory system, it’s labeled an embolus.
The dog’s kidneys, intestines, legs, and brain can be affected when the aorta can’t efficiently distribute blood carrying oxygen to them.
Symptoms
The Lab’s symptoms weren’t particularly noticeable at first. One evening, he acted restless and circled a lot. His new owners thought his endless pacing one night might be due to a change in food even though they had transitioned his diet as the vet suggested. When he started vomiting, howling, and stumbling a bit, they quickly transported him to the animal hospital.
Other typical symptoms of aortic thromboembolism in dogs include pain in the legs, behavior that suggests anxiety, paralysis, an odd gait or inability to walk, or trouble breathing. Some dogs develop nail beds and pads of their feet that are pale or bluish. Hypothermia is an additional sign.
Causes
One of the principal causes of a canine aortic thromboembolism is any type of cardiomyopathy. A dog with this condition has an enlarged or dilated heart. Sepsis, protein-losing nephropathy, and an infection in the bloodstream are all considered culprits.
Vets concerned about the possibility of this type of clot often checked for hyperadrenocorticism. The black Lab had undergone tests with conflicting results regarding hyperadrenocorticism shortly before the development of his bizarre symptoms because of changes in his weight.
Diagnosis
A vet who sees a dog with the symptoms of an aortic thromboembolism will try to keep the pet quiet while performing a complete physical exam and taking a detailed medical history. Although standard procedure includes taking a complete blood count, blood coagulation studies often fail to reveal significant problems. However, they’re useful in determining the correct dosage when blood-clotting medication becomes necessary.
Sometimes X-rays show fluid in the dog’s lungs or an enlarged heart. Both an echocardiogram and an electrocardiogram can help make a diagnosis. Use of an abdominal ultrasound or special-contrast X-rays reveals the problem in some dogs.
Treatment
Veterinary professionals consider this condition a serious medical problem and advise immediate hospitalization to treat it and avoid heart failure. To prevent the formation of more blood clots, they administer anticoagulant medication intravenously, though these drugs don’t affect the existing embolism. Sometimes vets prescribe aspirin.
One of the biggest challenges in treating this condition is keeping the dog quiet and getting him or her to eat. Often, the animal is in substantial pain and requires medication for it. Some pets receive oxygen when breathing is difficult. If medical treatment fails to resolve the embolus, the dog will require surgery to remove the clot.
Overall, the prognosis for these dogs isn’t particularly positive. Those who survive the initial episode will need to follow an indoor lifestyle and will require frequent monitoring by their respective vets.
Despite an initial successful treatment and monitoring, the adopted black Lab did not survive a second aortic thromboembolism eight months later.
Sources:
http://www.petmd.com/dog/conditions/cardiovascular/c_dg_aortic_thromboembolism#.TwNLHfI8eoU
http://www.bobmckee.com/Client%20Info/Cardiac/AorticThrombi.html
Personal experience as an animal rescuer