HEMOSTATIC FACTORS AND INHIBITORS AND CORONARY-ARTERY BYPASS-GRAFTING- PREOPERATIVE ALTERATIONS AND RELATIONS TO GRAFT OCCLUSION

Graft closure remains a major problem after coronary artery bypass sur gery. While a number of graft characteristics influencing the risk of occlusion have been defined, the role of haemostatic factors and inhib itors has not been studied in detail. The present study examined the t ime course of changes in blood coagulation and fibrinolytic function a fter coronary artery bypass grafting in 20 consecutive patients. Pre- and postoperative determinations of haemostatic factors and inhibitors were also related to the presence of graft occlusion assessed by angi ography at three months after surgery. A broad panel of haemostatic te sts was used preoperatively, on the first, third and eight postoperati ve days, and at three months after surgery. A particular emphasis was placed on fibrinogen, factor VII activity, von Willebrand factor (vWF) , plasminogen activator inhibitor-1 (PAI-1) activity, anticoagulant pr oteins C and S, thrombin-antithrombin complex and D-dimer. A marked ac tivation of the coagulation cascade was noted postoperatively along wi th enhanced degradation of cross-linked fibrin. The degree of activati on of blood coagulation and fibrinolysis differed widely between indiv iduals and appeared to relate only partly to the acute phase reaction produced by the surgical trauma. Preoperative values of haemostatic fa ctors and inhibitors showed fairly weak associations with the levels o f postoperative determinations. Basal tPA and factor VIII levels, fibr inogen and TAT concentrations on the third and eighth postoperative da y, and factor VII amidolytic activity on the third postoperative day d iffered (p <0.05) between patients with and without occluded grafts at reangiography. Accordingly, combined pre- and postoperative assessmen t of haemostatic function may contribute to the identification of indi viduals at risk for early graft closure after coronary artery bypass g rafting.