A major concern for owners of cats diagnosed with hypertrophic cardiomyopathy (HCM) is the development of clots in the heart. Cats with HCM that develop clots have a significantly worse prognosis than those that do not.
The currently accepted therapy to make clot formation less likely is a drug called clopidogrel (Plavix), which helps prevent platelets (cells that aggregate together in the initial formation of a clot) from coming together. Unfortunately, this medication alone is often not effective at preventing clots or a recurrence of clots. Some cats seem to have genetic resistance to the effects of clopidogrel.
A recent study performed at the University of California at Davis investigated the effects of adding rivaroxaban (a drug that works on a different component of the clot-forming pathway) to clopidogrel therapy on the ability of feline platelets to aggregatein nine healthy cats, as a first step in determining whether dual antithrombotic treatment (DAT) might benefit cats with HCM.
With the combination therapy, the cats showed definite changes in clotting ability. DAT was more effective at decreasing platelet aggregation than either drug alone. Currently, rivaroxaban is expensive. While more research is needed, including a trial in cats with HCM, DAT may prove to be a life saver for many cats with HCM.ν
Lo, S., et al. “Synergistic inhibitory effects of clopidogrel and rivaroxaban on platelet function and platelet-dependent thrombin generation in cats.” Journal of Veterinary Internal Medicine, May 19, 2023.
