Assessment of hemostasis in hyperthyroid and euthyroid cats using two viscoelastic assays and platelet aggregometry.

Abstract

BACKGROUND: Hyperthyroidism in humans is associated with a hypercoagulable state and an increased risk of thromboembolism. OBJECTIVE: To evaluate hemostatic variables in hyperthyroid and euthyroid cats with the hypothesis that hyperthyroid cats will have evidence of altered hemostasis consistent with a potential hypercoagulable state. ANIMALS: Client-owned hyperthyroid (n&#x2009;=&#x2009;16) and euthyroid (n&#x2009;=&#x2009;15) cats over 8&#x2009;years of age. METHODS: Prospective observational study. Hyperthyroid and euthyroid cats were enrolled. Rotational thromboelastometry (ROTEM), whole-blood platelet impedance aggregometry (WBPIA) and a point-of-care viscoelastic coagulation monitor (VCM-Vet) were performed immediately after minimally traumatic venipuncture under sedation. RESULTS: Hyperthyroid cats had significantly higher values for variables as assessed by VCM-Vet: A10 (34 [17-47] vs 25 [17-38], P&#x2009;=&#x2009;.003); A20 (39.5 [23-55] vs 31 [21-45], P&#x2009;=&#x2009;.003); and MCF (41 [24-58] vs 35 [22-49], P&#x2009;=&#x2009;.03). Hyperthyroid cats had significantly different values versus the euthyroid cohort as assessed by different ROTEM channels: increased A10, INTEM (61.5 [39-75] vs 54 [23-66], P&#x2009;=&#x2009;.007) and FIBTEM (18 [10-35] vs 13 [2-27], P&#x2009;=&#x2009;.01); increased A20, INTEM (68 [45-78] vs 61 [30-70], P&#x2009;=&#x2009;.006) and FIBTEM (17 [10-34] vs 11 [2-25], P&#x2009;=&#x2009;.002); increased MCF, EXTEM (72 [65-81] vs 69 [34-78], P&#x2009;=&#x2009;.04), INTEM (70 [45-85] vs 62 [35-71], P&#x2009;=&#x2009;.01) and FIBTEM (18 [13-37] vs 14 [3-27], P&#x2009;=&#x2009;.02); increased alpha angle, EXTEM (80 [68-85] vs 76 [41-84], P = .01); shortened CT, EXTEM (52.5 [29-73] vs 60 [52-92], P&#x2009;=&#x2009;.003) and FIBTEM (52.5 [16-75] vs 65 [53-165], P&#x2009;=&#x2009;.001); and decreased ML, FIBTEM (20 [1-36] vs 33 [19-59], P&#x2009;<.001). No significant differences were found with WBPIA. CONCLUSIONS AND CLINICAL IMPORTANCE: The hyperthyroid cats in this study had evidence of altered hemostasis as assessed by 2 viscoelastic methodologies, and characterized by increased clot amplitude, firmness, and faster coagulation times vs euthyroid controls.