If you're a cat owner, it's important to be aware of saddle thrombus – a rare, life-threatening condition found in cats. A saddle thrombus in cats is caused by a blood clot that forms in the aorta, the large artery that carries blood from the heart to the rest of the body. The clot can block blood flow and cause serious health problems for affected cats.
What is a saddle thrombus in cats?
Aortic thromboembolism or saddle thrombus is a relatively prevalent condition in cats with hypertrophic cardiomyopathy (HCM). It occurs when a blot clot lodges in the distal aortic bifurcation. The aorta in cats bifurcates or splits to provide blood flow to each hindlimb. The junction in which the aorta bifurcates is a common location for blood clots to obstruct and is why cats with saddle thrombus often become paralyzed in their hind end. Saddle thrombus in cats most often affects middle-aged males, 8-12 years of age.
What causes saddle thrombus in cats?
Saddle thrombus or aortic thromboembolism occurs most commonly in cats with heart disease, specifically hypertrophic cardiomyopathy (HCM). Cats that have severe HCM will often have a dilated or enlarged left atrium. This enlarged heart chamber (left atrium) will promote thrombus formation inside the heart due to a hypercoagulable state. If the thrombus is ejected into the aortic, it can result in a saddle thrombus.
What are the symptoms of saddle thrombus in cats?
The most common symptom of saddle thrombus is sudden paralysis in the hindquarters. The cat may also have a lack of appetite, weight loss, and weakness.
How is saddle thrombus in cats diagnosed?
Saddle thrombus in cats is typically diagnosed with a combination of clinical signs, detailed physical examination, imaging studies (x-rays, ultrasound), and blood tests. The physical examination may reveal a decrease or absence of a pulse in the hindquarters. Rectal temperature measurement will be below normal due to the lack of blood flow. Affected limbs are usually cool to the touch, and nail beds and footpads may be blue or pale. An echocardiogram (heart ultrasound) should be performed and may reveal an enlarged left atrium and small free-floating thrombi.
What is the treatment for saddle thrombus in cats?
Unfortunately, no effective therapy for saddle thrombus has been identified for cats. Medications designed to break down blood clots and relieve the saddle thrombus have not been successful. Surgery to remove the saddle thrombus in cats is associated with a high mortality rate and is no longer performed or recommended.
It is estimated that a reasonable (but unknown) percentage of cats break down their own saddle thrombus over time. If proper pain management is implemented, supportive care including anticoagulants and blood thinners can be attempted for 2-3 days.
Prevention of saddle thrombus in cats
Anti-platelet therapies including aspirin or clopidogrel (Plavix®) should be started prior to the development of saddle thrombus. For example, if your cat is undergoing an echocardiogram to assess the heart for any reason, and thrombi are found in the left atrium, it would be a good idea to start therapy in an attempt to reduce the occurrence of saddle thrombus. It is important to note that these therapies do not break down the thrombus but may aid in the prevention.
What is reperfusion injury and why it is important?
Reperfusion injury is a condition that can occur after the restoration of blood flow to an organ or tissue and usually occurs within 10-60 minutes. The injury is a result of the sudden influx of white blood cells such as neutrophils and macrophages into the cells, which can severely damage cells and tissues. It is one of the main reasons why saddle thrombus in cats is associated with high mortality rates if they do make a recovery. Treatments for reperfusion injury include lidocaine and ketamine but more studies need to be done in veterinary medicine.
What is the prognosis for saddle thrombus in cats?
The prognosis for saddle thrombus in cats is poor. The majority of cats that are diagnosed with saddle thrombus will die or be euthanized from the condition. However, a small percentage of cats may break down their own saddle thrombus over time and recover. Proper pain management and supportive care are essential for these cats.
Saddle thrombus in cats, also known as aortic thromboembolism, is a life-threatening condition. The condition is caused by a blood clot that forms in the aorta, the large artery that carries blood from the heart to the rest of the body. The clot can block blood flow and cause serious health problems. saddle thrombus is most often seen in cats with heart disease. There are no definitive treatments available for saddle thrombus in cats. As the vast majority of cases are a result of hypertrophic cardiomyopathy, if your cat is diagnosed with this condition it is very important to have an echocardiogram performed to assess if your cat is at risk for saddle thrombus. If you are concerned that your cat may be at risk for saddle thrombus, please contact your veterinarian.