Clinical use of tissue plasminogen activator for systemic thrombolysis in dogs and cats

Systemic administration of tissue plasminogen activator (tPA) is seldomly reported in dogs and cats. Client-owned animals receiving tPA (2010–2020). Medical records of dogs and cats receiving tPA for distant known/suspected thrombus were reviewed. Fourteen dog visits (24 injections) and five cat visits (six injections) were included. Canine known/suspected thrombus included pulmonary thromboembolism (n=6), intracardiac thrombus (n=4), aortic thrombus (n=1), cranial vena cava thrombus (n=2), and femoral and iliac veins thrombus (n=1). Various canine primary diseases were represented, but open-heart surgery was the most common cause. Median time between diagnosis/suspicion of thrombus and tPA injection was 24.5 h (range, 3–150 h). Mean total tPA dose was 1.0±0.78 mg/kg. Clinical improvement occurred in 93% of dogs. Non-fatal complications were reported in 14% of dogs. Dogs’ survival to discharge was 78.6% without identifiable non-survivor characteristics. Feline known/suspected thrombus included unilateral feline aortic thromboembolism (FATE) (n=2), bilateral FATE (n=2), and right renal artery thrombus. Feline primary diseases included cardiomyopathy (n=5). Median time between diagnosis/suspicion of thrombus and tPA injection was 4 h (range, 2–17 h) and median total tPA dose was 1.0 mg/kg (range, 0.6–1.4 mg/kg).Clinical improvement occurred during 40% of the visits. All cats (n=3) with acute kidney injury (AKI) at admission developed worsening AKI and reperfusion injury. Of the remaining two visits, one developed a non-fatal AKI. Cats’ survival to discharge was 40%. Systemic thrombolysis with tPA seems to be effective and safe in dogs. More investigation is needed in cats.