Thromboembolic diseases are common in cats with hypertrophic cardiomyopathy (HCM), but they are difficult to diagnose using conventional laboratory methods. Moreover, cats with HCM are usually placed on anticoagulants or antiplatelet agents to prevent thrombosis, but again we lack an adequate means of monitoring treatment efficacy using traditional methodology.
The thrombelastograph (TEG®) allows for a global evaluation of the hemostatic system; while conventional coagulation tests typically evaluate only one part of the coagulation system, the TEG® simultaneously examines the interaction between platelets, clotting factors, the fibrinolytic system, and clot retraction mechanisms. Since its inception, the TEG® has been widely employed in human clinical medicine and research, only recently gaining popularity in veterinary medicine.
To our knowledge, reference values for citrated native TEG® in cats have not been reported in the literature. The purpose of this study was to establish TEG reference ranges in healthy cats using the whole blood citrated native technique. We sampled 28 clinically healthy adult cats based on normal PE, CBC, and hemostasis profile results and with no previous history of bleeding disorders. The sample population ranged in age from 1 to 7 years old; 14 cats were castrated males and 14 cats were spayed females. Samples were obtained in non-sedated animals via medial saphenous venipuncture using a 21 gauge butterfly catheter. A 3ml sterile syringe prepared with 0.3ml of 3.2% buffered sodium citrate anticoagulant was used for blood collection and samples were stabilized for 30-40 minutes at room temperature prior to being re-calcified and analyzed in the TEG® according to the manufacturer's instructions. We obtained the following values (mean±SD): R = 6.104±3.646 min; K = 4.21±3.21 min; angle = 47.92±14.51 deg; MA = 48.06±10.02 mm; G = 4974±1919 d/sc; CL60 = 83.95±14.43%, and LY60 = 7.86±10.21%. Interestingly, there were two distinct patterns of clot maintenance, one with minimal LY60 (0.2 to 3%), which is comparable to that seen in dogs and horses, and another with marked increases in LY60 (>7%), which we suspect is due to platelet retraction mechanisms.