Hemostatic Findings in Ascitic Fluid: A Cross-Sectional Study in 70 Dogs

Background: Ascitic fluids of horses and humans have fibrinolytic activity, independent of the underlying mechanism of fluid formation. Objective: To determine whether coagulation and fibrinogenolytic/fibrinolytic activity (ie, low fibrinogen and increased fibrin–fibrinogen degradation products [FDPs], D-dimer, or both) occur in all types of ascitic fluid in dogs. Animals: A total of 70 client-owned dogs with ascites. Methods: In this cross-sectional study, dogs were categorized based on the pathophysiology of fluid formation into 4 groups: transudates due to decreased osmotic pressure, transudates due to increased hydrostatic pressure, exudates, and hemorrhagic ascites. Fibrinogen, FDPs, and D-dimer concentrations were measured and then compared in both ascitic fluid and plasma. Results: Ten dogs had transudates due to decreased colloid osmotic pressure, 18 had transudates due to increased hydrostatic pressure, 13 had exudates, and 29 had hemorrhagic ascites. Ascitic fibrinogen concentrations (n = 70) were significantly lower (median = 59 mg/dL; range: 59–122 mg/dL) than those in the plasma (median = 168 mg/dL, range: 59–879 mg/dL; P <.0001). Ascitic FDPs concentrations (n = 70) were significantly higher (<5 μg/mL: 3/70 dogs, ≥5 to <20 μg/mL: 11/70 dogs, ≥20 μg/mL: 56/70 dogs) than those in the plasma (<5 μg/mL: 17/70 dogs, ≥5 to <20 μg/mL: 28/70 dogs, ≥20 μg/mL: 25/70 dogs; P <.0001). Ascitic D-dimer concentrations (n = 70) were significantly higher (median = 3.98 μg/mL, range: 0.02–9.19) than those in the plasma (median = 0.11 μg/mL, range: 0.01–4.08; P <.0001). Analysis of the data for each of the 4 different types of ascites showed similar results to those of all the data analyzed together. Conclusions and Clinical Importance: Ascitic fluid of dogs has evidence of coagulation activation and fibrinogenolytic/fibrinolytic activity and that this phenomenon occurs independent of the underlying mechanism that leads to the formation of ascites.