Various local hemostatic agents with different modes of action;: an in vivo comparative randomized vascular surgical experimental study

Objectives. To evaluate the effects of different local hemostatic agents in a new high flow vascular experimental bleeding model. Design. Bovine thrombin combined with collagen matrix (bTcM), microporous polysaccharide hemospheres (MPH), freeze-dried rFVIIa with and without the combination of MPH were compared to a control group (solely compression) in a randomized fashion (20 animals/group). Primary endpoint was hemostasis, and secondary endpoints were time to hemostasis, blood loss, and blood pressure at hemostasis. Methods. The common carotid artery of heparinized rats was ligated proximally and transected. Compression was applied for one minute followed by application of the topical hemostatic agent. Compression was maintained for another two minutes followed by re-evaluation of hemostasis: if bleeding continued additional compression was applied and thereafter bleeding was checked every minute until hemostasis. Results. All animals in the bTcM group obtained hemostasis compared to 20% in the control. group (p < 0.0001). The combination of MPH and rFVIIa (70% hemostasis) also showed a significant hemostatic capacity compared to control group (p < 0.001). None of the other active treatment groups differed compared to control group. Animals treated with bTcM had a significantly shorter time to hemostasis compared to animals in the other active treatment groups. No significant difference in blood loss and blood pressure at hemostasis was detected. Conclusions. The most effective hemostatic agent was bTcM, followed by the combination of rFVIIa and MPH, while neither MPH nor rFVIIa alone displayed any hemostatic capacity compared to compression only.