Platelet Function Testing in Cats with Heart Disease Receiving Clopidogrel Therapy

Objective

To evaluate the effects of the blood thinners aspirin and clopidogrel on platelets in cats with hypertrophic cardiomyopathy (HCM) and other heart diseases.

Background

Hypertrophic cardiomyopathy (HCM) is the most common heart disease of cats. In this disease the heart muscle becomes abnormally thick and one of the chambers of the heart (the left atrium) becomes enlarged. A severe complication of this disease is formation of a blood clot in the enlarged left atrium which then cuts off the blood supply to the back legs, analogous to a stroke. This condition is given the acronym FATE (Feline Aortic Thrombo-Embolism), which sadly reflects the fact that at least half of cats afflicted by this disorder die. In an effort to prevent FATE, cats are treated with either acetylsalicylic acid (aspirin) or clopidogrel (PlavixÒ). These are blood-thinners which block the function of platelets, the blood cells responsible for the first steps in blood clotting. Unfortunately some cats treated with these drugs still die of FATE. Although there have been some studies that have looked at the effects of these drugs in normal cats, and some studies that have looked at the blood clotting system in cats with HCM with or without FATE, no study has actually examined the effects of aspirin or clopidogrel in cats with HCM to see if platelets are actually being blocked. Indeed, a survey of veterinary cardiologists revealed that the treatment of HCM in general is surprisingly based on little scientific evidence.

This study aims to gather information that will eventually help to optimize platelet function in cats with HCM and other heart diseases in order to improve how they are managed and monitored in attempts to prevent FATE. This study will determine if platelets are indeed being inhibited by aspirin and/or clopidogrel. A limitation of this study is that currently the degree of platelet inhibition needed to prevent FATE is not known. With long-term follow-up of cats that have had platelet function tests, we may be able to answer this question. As data become available, there may be information with respect to whether therapy may be helping the prevention of FATE and the type of blood thinner which may be recommended for each individual feline patient.

Incentives

  • Study covers cost of platelet function tests

Samples required

  • Blood

Inclusion Criteria

  • Planned treatment with clopidrogrel therapy at any clinic (blood samples must be obtained at OVC)

Researchers

Dr. Tony Ogg (PI)

Alison Downie

Contact

Email: clinical.research@uoguelph.ca

Alison Downie
Work Cell #: 226-924-5792

Vicky Sabine, PhD
Clinical Research Coordinator, OVC
Email: vsabine@uoguelph.ca; Work Cell #: 226-218-0338


Funded by OVC Pet Trust