he effects of supraceliac aortic clamping on the anticoagulant effects of heparin

Background Coagulopathy is frequently encountered during supraceliac aortic clamping. Patients are routinely heparinized during these operations. This experiment was undertaken to evaluate the effect of supraceliac aortic crossclamping (XC) on heparin pharmacodynamics. material and methods: Fourteen mongrel dogs were randomly divided into three groups: Group 1 (X; n=6), 90 minutes aortic XC; Group 2 (SH; n=4), sham operation and heparin, 100 mg/kg intravenously; and Group 3 (XH; n=4), heparin, 100 mg/kg intravenously 3 minutes before XC. Prothrombin time (PT) and partial prothrombin time (PTT) were measured serially. Heparin concentrations were estimated via automated titration with protamine sulfate. Results After XC, PTT is increased during reperfusion. Heparin administration (XH) before aortic XC increases PTT above those with X or SH. Anticoagulation was potentiated and prolonged by XC. There was no difference in heparin concentration or PT. Conclusion Supraceliac aortic clamping significantly affects heparin pharmacodynamics and may contribute to coagulopathy.