Inflammatory and fibrinolytic states in cats with and without cardiogenic atrial/arterial thromboembolism stratified by the presence and type of congestive heart failure.

Objective: To assess whether cats with cardiogenic pleural effusion have less systemic inflammation or an enhanced systemic fibrinolysis, preventing cardiogenic atrial/arterial thromboembolism compared to cats with cardiac disease without pleural effusion.

Materials and methods: Cross-sectional study evaluating cats presented with cardiac disease: without congestive heart failure (n = 246), with cardiogenic pulmonary oedema (49) and with cardiogenic pleural effusion (94). At presentation, plasma fibrinogen and serum amyloid A were measured, and the fibrinogen:serum amyloid A (a marker of systemic fibrinolysis) was calculated. The frequency of cardiogenic atrial/arterial thromboembolism among groups was compared using the chi-squared test, whereas the other biomarkers were analysed using non-parametric tests.

Results: The prevalence of cardiogenic atrial/arterial thromboembolism was significantly higher in cats with pulmonary oedema (18/49, 36.7%) compared with cats without congestive heart failure (23/246, 9.3%) and with cardiogenic pleural effusion (9/94, 9.6%). The median serum amyloid A concentration in cats with cardiogenic pleural effusion (3.35 mg/L) was significantly higher than that in cats without congestive heart failure (0.65 mg/L), whereas no significant differences were found between cats with pulmonary oedema (1.4 mg/L) and those with pleural effusion or without congestive heart failure. After excluding 50 cats with cardiogenic atrial/arterial thromboembolism, there were 223 cats without congestive heart failure, 31 with pulmonary oedema, and 85 with pleural effusion. In the 85 cats without cardiogenic atrial/arterial thromboembolism and with cardiogenic pleural effusion, the median fibrinogen:serum amyloid A ratio (58) was significantly lower than the fibrinogen:serum amyloid A ratio (316) observed in the remaining 254 cats without cardiogenic atrial/arterial thromboembolism from the other two groups combined.

Clinical significance: Enhanced systemic fibrinolysis may play a role in the lower cardiogenic atrial/arterial thromboembolism risk of cats with cardiogenic pleural effusion.