Regular Article Comparison of porcine and human coagulation by thrombelastometry ☆ Ulf Kessler a,e , Tamar Grau a , Fabrizio Gronchi d , Steffen Berger a , Sebastian Brandt b , Hendrik Bracht c , Carlo Marcucci d , Zacharias Zachariou a , Stephan M. Jakob c, ⁎ a Department of Pediatric Surgery, Inselspital, Bern University Hospital and University of Bern, Switzerland b Department of Anaesthesiology and Pain Therapy, Inselspital, Bern University Hospital and University of Bern, Switzerland c Department of Intensive Care Medicine, Inselspital, Bern University Hospital and University of Bern, Switzerland d Department of Anesthesia, CHUV, Lausanne University Hospital and University of Lausanne, Switzerland e Department of Visceral Surgery, CHUV, Lausanne University Hospital and University of Lausanne, Switzerland abstract article info Article history: Received 2 October 2010 Received in revised form 15 March 2011 Accepted 17 March 2011 Available online 13 April 2011 Keywords: Thrombelastometry Coagulation Platelets Fibrinogen Animal Pig Introduction: Although the pig is a standard model for the evaluation of various diseases in humans, including coagulopathy, it is not clear whether results in animals can be extrapolated to man. Materials and methods: In 75 anesthetized pigs, we assessed reagent-supported thrombelastometry (ExTEM®), platelet-blocked thrombelastometry (FibTEM®), and aprotinin thrombelastometry (ApTEM®). Results were compared to values from 13 anesthetized humans. Results (median, 95% CI): ExTEM®: While clot strength was comparable in pigs (66 mm, 65–67 mm) and in humans (64 mm, 60–68 mm; NS), clotting time in animals was longer (pigs 64 s, 62–66 s; humans 55 s, 49– 71 s; P b 0.05) and clot formation time shorter (pigs 52 s, 49–54 s; humans 83 s, 67–98 s, P b 0.001). The clot lysis index at 30 minutes was lower in animals (96.9%, 95.1-97.3%) than in humans (99.5%, 98.6-99.9%; P b 0.001). ApTEM® showed no hyperfibrinolysis in animals. Modification of the anesthesia protocol in animals resulted in significant ExTEM® changes. FibTEM®: Complete platelet inhibition yielded significantly higher platelet contribution to clot strength in pigs (79%, 76-81%) than in humans (73%, 71–77%; P b 0.05), whereas fibrinogen contribution to clot strength was higher in humans (27%, 24-29%) than in animals (21%, 19-24%; P b 0.05). Conclusions: Maximum clot firmness is comparable in human and porcine blood. However, clot lysis, platelet and fibrinogen contribution to clot strength, as well as initiation and propagation of clotting, are considerably different between pigs and humans. In addition, anesthesic drugs seem to influence thrombelastometry in animals. Accordingly, coagulation abnormalities in pigs subjected to diseases may not necessarily represent the coagulation profile in sick patients. © 2011 Elsevier Ltd. All rights reserved. Introduction Coagulation abnormalities may have a major effect on outcome in critically ill patients who have trauma or sepsis [1]. However, monitoring coagulation in patients with critical illnesses such as sepsis can be problematic, and the best approach remains a current matter of debate [2,3]. Pathophysiological mechanisms of coagulation abnormalities, monitoring, and treatment options are frequently evaluated in animals. Here, the pig is a standard model, because the physiology of major organ functions—including coagulation—is comparable to that of humans [4,5]. It is unclear, however, whether results from studies on porcine coagulation can be extrapolated to man. For both the clinical setting and for research purposes, thrombe- lastography (TEG) and thrombelastometry (RoTEM®), two similar techniques, are increasingly used to monitor hemostasis [5–7]. Both allow assessment of the entire clotting process, from initiation of clot formation to the point at which a clot reaches maximum firmness. In addition, testing stimulation of extrinsic coagulation and subsequent blockage of platelet function allows the differentiation of the platelet and the plasmatic components of clot firmness (Fig. 1). Previous studies have determined the normal range of RoTEM® variables in humans and in pigs [3,8]. With the exception of the aPTT test, all commercially available coagulation tests and RoTEM® were shown to be fully applicable to porcine blood. However, for complete platelet blocking in animals, 70 μl instead of 20 μl of FibTEM® reagent was needed [8]. Whereas duration of clotting initiation (CT) was Thrombosis Research 128 (2011) 477–482 Abbreviations: TEG, thrombelastography; RoTEM®, rotational thrombelastometry; MCF, maximum clot firmness; EXTEM®, extrinsic thrombelastometry; FibTEM®, fibrinogen thrombelastometry; CT, clotting initiation; CFT, clot formation; NS, not significant (P N 0.05). ☆ The experiments were carried out at the University of Bern. ⁎ Corresponding author at: Department of Intensive Care Medicine, Bern University Hospital, Inselspital, CH-3010 Bern, Switzerland. Tel.: + 41 31 632 1176; fax: + 41 31 632 9644. E-mail address: stephan.jakob@insel.ch (S.M. Jakob). 0049-3848/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.thromres.2011.03.013 Contents lists available at ScienceDirect Thrombosis Research journal homepage: www.elsevier.com/locate/thromres