According to the Ontario Stroke Network, stroke is the leading cause of adult disability in Canada and the third leading cause of death in humans – but do strokes affect companion animals and what are the signs and causes of stroke in pets?
“Strokes appear to be less common in pets, but because their consequences can be fatal, it is important to detect at-risk patients and treat them preemptively,” says OVC Internal Medicine Resident Dr. Sophie Saati. A stroke happens when a blood clot forms in a blood vessel, cutting off blood flow in the brain. Abnormal blood clot formation in pets appears to happen more commonly in other parts of the body, such as the lungs, heart and kidneys. “Depending where the blood clot occurs, clinical signs will differ. For example, neurological deficits if it happens in the brain, and difficulty breathing if it happens in the lungs,” Saati explains.
Abnormal blood clot formation can be common with certain diseases. “Conditions that can be associated with this include cancer, heart diseases, autoimmune diseases, endocrine diseases (hormone disorders) and some types of kidney and intestinal diseases.”
While the appearance
of abnormal clotting in pets varies widely, some diseases, such as immune-mediated hemolytic anemia, a life-threatening disorder where a dog’s immune system destroys its red blood cells, have a high mortality rate (about 50 per cent) and up to 80 per cent of those deaths can be attributed to abnormal blood clot formation.
For this reason, Saati focused her graduate student clinical research at OVC on platelet function tests. Platelets, one component in the blood responsible in forming clots, have their action reduced by some blood thinners, which decreases the chance of blood clot formation and the risk of stroke.
Saati’s study examined the effectiveness of a blood-thinning medication called clopidogrel, a common drug used to prevent blood clots in both veterinary and human medicine. Saati and her advisor Dr. Anthony Abrams-Ogg suspected that some dogs may be resistant to blood thinning medications, which may leave them vulnerable and more likely to suffer abnormal clotting if their medication isn’t working properly.
“Assessing platelet function in dogs receiving blood thinning therapy helps ensure that we know the medication is working and that it is reducing their risk of suffering a stroke and abnormal blood clotting in other organs,” says Abrams-Ogg. In the past, veterinarians working in general practices have had to refer patients to academic institutions such as OVC to access platelet function tests. Saati hopes the results of her study will help implement routine blood clot function monitoring in general veterinary practice.
“One of the platelet function tests that we investigated, Plateletworks, can be performed in general practices using materials that are readily available,” says Saati. “Ideally, our research findings will increase access and availability to preventive treatments and tests for effective blood thinner treatments when pets at-risk need it the most.”
Read more in Best Friends Magazine.