Is use of aprotinin safe with deep hypothermic circulatory arrest in aortic surgery? Investigations on blood coagulation.

Background: The perioperative blood coagulation and fibrinolysis system in patients who underwent aortic surgery under deep hypothermic circulatory arrest with or without aprotinin usage was investigated.
Methods and Results: Of 112 patients who underwent aortic surgery between December 1993 and April 1995, 60 had repair under deep hypothermic circulatory arrest. Thirty-nine patients had 2 million U aprotinin in pump priming and had no additional aprotinin. There were 20 patients with aortic dissections and 17 with atherosclerotic aneurysms. Twenty-two patients had left thoracotomy, and 17 had midsternotomy. Surgery consisted of replacement of the ascending aorta in 9 patients, total arch replacement in 11, distal arch replacement in 11, replacement of the descending aorta in 3, and replacement of thoracoabdominal aorta in 5. The control group was 21 patients who underwent operation under deep hypothermic circulatory arrest and retrograde cerebral perfusion but without aprotinin. Blood coagulation and fibrinolysis tests, consisting of activated clotting time, prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, plasminogen, alpha 2-plasmin inhibitor, thrombin-antithrombin complex, plasmin inhibitor complex, fibrin degenerative products, and D-dimer complex, were performed at various stages of surgery, before heparin administration, after heparin, 60 minutes and 120 minutes after beginning of the extracorporeal circulation, 1 hour after protamine administration, and 6 hours after protamine. Statistical analysis was performed with Student's t test, chi 2 test, and ANOVA. The amount of bleeding after perfusion was less in the aprotinin group, and bleeding during first 24 hours in the intensive care unit was less. Blood examination revealed that prothrombin time was higher after cessation of cardiopulmonary bypass in the aprotinin group. Thrombin-antithrombin III complex and alpha 2-plasmin inhibitor were higher during and after bypass in the aprotinin group. There was no difference in activated clotting time, activated partial thromboplastin time, fibrinogen, antithrombin III, plasminogen, plasmin inhibitor complex, fibrin degenerative products, and D-dimer complex.
Conclusions: Clinical advantages of hemostatic effects of low-dose aprotinin and no apparent deleterious effects were demonstrated in patients who underwent aortic surgery under deep hypothermic circulatory arrest with retrograde cerebral perfusion. However, blood coagulation and fibrinolytic studies revealed subclinical hypercoagulation. Therefore, and adequate dose of heparin is required during deep hypothermic circulatory arrest.