To evaluate the pathogenesis of bleeding tendency in vascular surgery in elderly patients, the serial changes in various parameters of coagulation and fibrinolysis were investigated perioperatively in 30 patients undergoing vascular surgery and in 18 patients undergoing general surgery (control). The platelet count, platelet aggregability and plasminogen activity were lower in the group of vascular surgery than in the control group perioperatively. Thrombin-antithrombin Ⅲ complex(TAT) and plasmin-α(2) plasmin inhibitor complex(PIC) levels were high during operation. Postoperatively, the TAT level gradually decreased but the D-dimer level was high postoperatively. Although platelet aggregability increased significantly with age in the group of general surgery, it tended to decrease in that of vascular surgery. TAT and PIC levels tended to increase but the α(2) plasmin inhibitor(α(2)PI) and fibrinogen levels tended to decrease with age. In 22 patients undergoing graft replacement with abdominal aortic aneurysm, a negative correlation was observed between preoperative α(2)PI and intraoperative blood loss. However, a positive correlation was evident between the preoperative PIC level and intraoperative blood loss.
These findings suggest that in vascular surgery, activities of coagulation and fibrinolysis increase and the postoperative hypercoagulable state is transient, although secondary fibrinolysis is stationary in a high level, and that in elderly patients with vascular disorders coagulating factor and anti-fibrinolytic factor tend to decrease. Surgery may induce a bleeding tendency. Furthermore, α(2)PI and PIC might be main factors in intraoperative blood loss.