Cats with heart disease may form blood clots in the heart, which can travel to the hind legs and cut off blood flow. This is referred to as FATE (Feline Aortic Thromboembolism), which has a fatality rate of about 50%. Abnormal blood clots can also form in cats with other disorders. Clopidogrel, which blocks platelet function, is one of the most effective drugs in preventing clots in cats. However, some cats are resistant to clopidogrel. This is reported to occur in about 20% of cats.
Historically, assessing clopidogrel effect using a blood test was difficult. Specialized tests had to be run using equipment not available in regular veterinary clinics, and samples were not stable enough to be shipped to a lab. As such, cats needed to travel to large university hospitals (potentially hours away) to have testing done. This often does not occur, and so cats are treated without knowing if the drug is working.
We have validated a platelet testing system (Plateletworks ADP) on two in-house blood analyzers. We have also validated local shipping of samples for another test on a specialized analyzer (PFA-200). As combinations of tests are considered superior to single tests for platelet function assessment, we believe that a methodology comprised of Plateletworks testing and shipment for PFA-200 analysis will allow veterinarians to identify clopidogrel-resistant cats in their own practices.
This proposal is for a proof-of-feasibility study culminating 8 years of research and will serve to demonstrate the possibility of this testing method across long distances.