The much-anticipated results of a study comparing the treatment of cats that had experienced blood clot formation secondary to heart disease were recently presented at the annual forum of the American College of Veterinary Internal Medicine, held in Seattle, Washington from June 12 to June 15, 2013.
Thromboembolism (blood clot formation) is, unfortunately, a common sequel of cardiac disease in cats. Clots that form in the hearts of cats with heart disease may be ejected to the body and may lodge in the arteries, blocking blood supply to areas downstream of this blockage and, in many cases, causing significant damage to vital organs and muscles. The most common place for these clots to lodge is where the aorta (the largest artery in the body) splits into the two major arteries that supply blood to the hind limbs. This region has been referred to as the “saddle,” and blood clots lodging here have been referred to as a “saddle thrombus.” Thromboembolism is a devastating consequence of heart disease in cats, and cats that experience this phenomenon are at risk of repeated thromboembolic events that may significantly worsen their prognoses. These cats also have a significantly worse prognosis than cats that have not experienced thromboembolism, and many cats that develop clots due to heart disease either die spontaneously or are euthanized.
The Feline Arterial Thromboembolism: Clopidogrel vs. Aspirin Trial (or FATCAT) study, headed by Dr. Dan Hogan at the Purdue University College of Veterinary Medicine, enrolled 76 cats that had experienced thromboembolism as a result of heart disease and had survived for between 1 and 3 months and randomized these patients to receive either clopidogrel or aspirin. The cats were then followed for 12 months to determine how each group compared with respect to recurrence of thromboembolism and survival.
The results of the FATCAT trial showed that cats receiving clopidogrel tolerated it well and survived longer, with a longer time to repeat thrombosis than did cats receiving aspirin. This is the first demonstration of a clinical benefit to the use of clopidogrel to treat cats that have experienced thromboembolism secondary to heart disease. Although this study does have its limitations (as most studies do), it provides objective data supporting the use of clopidogrel in the treatment of thromboembolism in cats with heart disease and sets the stage for future studies addressing treatment of this very important disease of cats.