Bilateral lysis of aortic saddle thrombus with early tissue plasminogen activator (BLASTT): a prospective, randomized, placebo-controlled study in feline acute aortic thromboembolism.

Abstract

OBJECTIVES: The aim of this study was to investigate the impact of tissue plasminogen activator (TPA) on the treatment of feline aortic thromboembolism (FATE). METHODS: Cats diagnosed with FATE involving &#x2a7e;2 limbs were enrolled in a prospective, multicenter, double-blinded, randomized, placebo-controlled study within 6&#x2009;h of an event. Diagnosis was made by clinical findings and one confirmatory criterion. Cats received placebo or TPA (1&#x2009;mg/kg/h with the first 10% by bolus). All cats received pain control and thromboprophylaxis. The primary outcome was a change from baseline in a published limb score at 48&#x2009;h. Secondary outcomes included 48&#x2009;h survival, survival to discharge and complication proportions. Statistical analyses included pattern-mixture models, logistic regression and Fisher's exact, Student's- and Mann-Whitney-Wilcoxon tests. RESULTS: Based on a power analysis, 40 cats were enrolled; however, only 20 survived to 48&#x2009;h (TPA, n&#x2009;=&#x2009;12; placebo, n&#x2009;=&#x2009;8 [&#x2009;=&#x2009;0.34]). There was a statistically significant improvement in limb scores compared with baseline for both groups (<0.001). Limb score at 48&#x2009;h was 1 point lower (better) in the TPA group (&#x2009;=&#x2009;0.19). Thrombolysis had no statistically significant effect on 48&#x2009;h survival (&#x2009;=&#x2009;0.22). Lower affected limb lactate was associated with better 48&#x2009;h survival (odds ratio 1.53, 95% confidence interval 1.08-2.17;&#x2009;=&#x2009;0.02). The survival to discharge rates were 45% (TPA) and 30% (placebo;&#x2009;=&#x2009;0.51). Complications in the TPA and placebo groups included acute kidney injury (22% and 19%, respectively;&#x2009;=&#x2009;1.00) and/or reperfusion injuries (33% and 19%, respectively;&#x2009;=&#x2009;0.45). CONCLUSIONS AND RELEVANCE: Survival and complication rates of acute FATE were not different with or without thrombolysis. High in-hospital mortality decreased the statistical power to detect a statistically significant difference between treatments with regard to our primary outcome.