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.