Thoracic aorta occlusion-reperfusion decreases hemostasis as assessed by thromboelastography in rabbits.
Perioperative hemorrhage and thrombosis are serious complications associated with major vascular surgery. We hypothesized that thoracic aortic occlusion-reperfusion in rabbits would adversely affect hemostasis as assessed by thromboelastographic variables (reaction time, alpha angle and G [a measure of clot strength]). Isoflurane-anesthetized rabbits underwent either sham operation (n = 10) or 30 min of aortic occlusion followed by 90 min of reperfusion (n = 10). Blood samples (350 microL) were exposed to 10 microL of either 0.9% NaCl or cytochalasin D (a platelet inhibitor, 10 microM final concentration) and analyzed for 1 h by using thromboelastography after 30 min of postpreparation equilibration and at 30 and 90 min of reperfusion. Aortic occlusion-reperfusion resulted in a significant (P: < 0.05) increase in reaction time, decrease in alpha angle, and decrease in G at 30 and 90 min of reperfusion compared with the sham-operated group. The decrease in hemostatic function after aortic occlusion-reperfusion was observed to the same degree in samples with or without platelet inhibition. There were no significant differences in platelet concentration between the sham-operated and aortic occlusion-reperfusion groups. Aortic occlusion-reperfusion decreased hemostatic function in rabbits primarily by decreasing the coagulation factor-dependent, platelet-independent contribution to clotting.


CONCLUSIONS
Thoracic aortic occlusion-reperfusion decreased hemostatic function in rabbits primarily by decreasing the coagulation factor-dependent, platelet-independent contribution to clotting. This decrease in hemostatic function may contribute to hemorrhagic complications associated with major vascular surgery.
Nielsen
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VG
Department of Anesthesiology, Division of Cardiothoracic Anesthesia, The University of Alabama at Birmingham, 35249, USA. vance.nielsen@ccc.uab.edu
Geary
B T
BT
D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology*; D001784:Blood Gas Analysis; D004573:Electrolytes / Q000097:blood; D006400:Hematocrit; D006439:Hemodynamics / Q000502:physiology; D006487:Hemostasis / Q000502:physiology*; D010976:Platelet Count; D011817:Rabbits; D015427:Reperfusion Injury / Q000503:physiopathology*; D013916:Thrombelastography / Q000379:methods*
D004573:Electrolytes