THE EFFECTS OF DIFFERENT ANESTHETIC REGIMENS ON FIBRINOLYSIS AND THE DEVELOPMENT OF POSTOPERATIVE ARTERIAL THROMBOSIS

Background: The purpose of this clinical trial was to compare the effe cts of different anesthetic and analgesic regimens on hemostatic funct ion and postoperative arterial thrombotic complications. Methods: Nine ty-five patients scheduled for elective lower extremity vascular recon struction were randomized to receive either epidural anesthesia follow ed by epidural fentanyl (RA) or general anesthesia followed by intrave nous morphine (GA). intraoperative and postoperative care were control led by protocol using predetermined limits for heart rate, blood press ure, and other monitoring criteria. Data collection included serial ph ysical examinations, electrocardiograms, and cardiac isoenzymes to det ect arterial thrombosis (defined as unstable angina, myocardial infarc tion, or vascular graft occlusion requiring reoperation). Fibrinogen, plasminogen activator inhibitor-1 (PAI-1), and D-dimer levels were mea sured preoperatively and at 24 and 72 h postoperatively. Results: Preo perative fibrinogen levels were similar in both groups, remained uncha nged after 24 h, and increased equally (45%) in the first 72 h postope ratively. PAI-1 levels in the GA group increased from 13.6 +/- 2.1 act ivity units (AU)/ml to 20.2 +/- 2.6 AU/ml at 24 h and returned to base line at 72 h. In contrast, PAI-1 levels in the RA group remained uncha nged over time. Twenty-two of 95 patients (23%) had postoperative arte rial thrombosis, 17 of whom had received GA and 5 of whom, RA. Preoper ative PAI-1 levels were higher in patients who developed postoperative arterial thrombosis (20.5 +/- 3.6 AU/ml vs. 11.2 +/- 1.4 AU/ml). Mult iple logistic regression analysis indicated that GA and preoperative P AI-1 levels were predictive of postoperative arterial thrombotic compl ications. Conclusions: impaired fibrinolysis may be related causally t o postoperative arterial thrombosis. Because RA combined with epidural fentanyl analgesia appears to prevent postoperative inhibition of fib rinolysis, this form of perioperative management may decrease the risk of arterial thrombotic complications in patients undergoing lower ext remity revascularization.