Comparison of coagulation and fibrinolysis in Irish Wolfhounds and age-matched control dogs using tissue plasminogen activator-augmented viscoelastic testing

Objective

To determine if Irish Wolfhounds (IWs), like other sighthounds, are hyperfibrinolytic compared with nonsighthound dogs using 2 native and tissue plasminogen activator (tPA)-enhanced viscoelastic assays, one that is whole blood-based (viscoelastic coagulation monitor [VCM]) and the other that is plasma-based thromboelastography (TEG).

Design

Cohort study.

Setting

University teaching hospital.

Animals

A convenience sample of 27 IWs recruited from the Irish Wolfhound Association of New England Specialty and the local community, and 27 healthy, age-matched, large-breed control dogs.

Interventions

None.

Measurements and Main Results

Blood samples including CBC, biochemistry, traditional coagulation, and viscoelastic testing were collected from IWs and control dogs. Twelve IWs had viscoelastic testing. IWs had lower fibrinogen concentrations (215.5 ± 57.8 vs 251.4 ± 64.5 mg/dL, P = 0.034) and formed weaker clots on both whole-blood VCM and plasma TEG assays (maximum clot firmness [VCM-MCF] = 39.4 [25.1–48.8] vs 48.5 [34.6–57.3], P = 0.0042; maximum amplitude [TEG-MA] = 22.7 [14.7–33.6] vs 32.2 [26.9–42.0], P < 0.0001). IWs were hyperfibrinolytic compared with control dogs on VCM whole-blood assays, with 25 U/mL tPA (lysis at 30 min [VCM-LI30] = 68.1 [0–100] vs\ 99.9 [63.3–100], P = 0.0009; lysis at 45 min [VCM-LI45] = 31.0 [0–100] vs 98.1 [38.4–100], P = 0.0002) but hypofibrinolytic compared with controls on TEG plasma assays with 50 U/mL tPA (lysis at 30 min [TEG-LY30] = 45.7 [4.6–94.6] vs 93.7 [12.3–96.5], P = 0.0004; lysis at 60 min [TEG-LY60] = 68.7 [29.7–96.8] vs 95.7 [34.4–97.6], P = 0.0003). Minimal fibrinolysis was measured on whole-blood VCM or plasma TEG assays without the addition of tPA, and there were no differences between the 2 groups.

Conclusions

Weaker clots were found in IWs than control dogs. With the addition of tPA, IWs had evidence of hyperfibrinolysis on whole-blood VCM assays and hypofibrinolysis on plasma TEG assays compared with control dogs. Without the addition of tPA, however, both groups of dogs showed minimal fibrinolysis on viscoelastic testing.