Introduction: The study objective was to describe the underlying diseases, predisposing factors, clinical signs and clinicopathologic abnormalities associated with thromboembolic disease of non-cardiogenic origin in cats.

Study Design: Necropsy-based retrospective study (1991–2002)

Results: Forty-eight cats with thromboemboli that were not associated with significant structural heart disease were identified in a retrospective study using case records from the small animal necropsy service of the University of Pennsylvania, from 1991 to 2002. Thirty-five cats presented for non-specific signs such as lethargy and anorexia while others presented for signs such as paresis (10) or dyspnea (10) that were referable to the location of the thromboemboli. Thromboembolic disease was suspected clinically in 12 of 48 cats. In cases where a single predisposing factor could be identified, thromboemboli were associated with neoplastic (9), infectious (7) and inflammatory (3) disease. Thirteen cats had multiple predisposing factors and no obvious predisposing factor could be identified in 16 cats. The thromboemboli were found in the systemic arteries (12), systemic veins (9), both systemic arteries and veins (7), pulmonary vasculature (7) and in both the pulmonary and systemic circulation (13). Eleven cats either died at home, presented in respiratory or cardiac arrest, or arrested shortly after presentation to the emergency service. Two cats arrested later during hospitalization and the remainder were euthanized (35). No sex or breed disposition was found. There were no significant differences in serum biochemistries, coagulation profiles, lactate, Doppler blood pressure or rectal temperature when groups were compared by primary disorder. Cats with neoplasia as the underlying disorder were significantly older (median 13.5 years, p=0.04). Cats with infectious disease had statistically significant higher white blood cell counts (median 35,000/μl, p=0.03) and cats with inflammatory disease had significantly longer hospital stays (median 3 days, p=0.006).

Conclusion: These results suggest that most cats with non-cardiac related thromboemboli often have multiple predisposing factors, non-specific signs and non-specific changes on laboratory parameters. More sensitive tests for hypercoagulability may aid in diagnosing thromboemboli in cats.