Epidural anaesthesia prolonged into the postoperative period prevents stress response and platelet hyperaggregability after peripheral vascular surgery

The occlusion rate of peripheral vascular grafts depends on technical as well as endogenous factors. Platelets play an integral part in graft failure and it has been suggested that anaesthesia may influence platelet function. In order to evaluate the influence of anaesthesia on stress response and platelet function in peripheral vascular surgery, patients ( n =18) were allocated to either general anaesthesia (GA; n =9) followed by alleviation of postoperative pain with intramuscular analgesics or to lumbar epidural anaesthesia (EPI; n =9) which was continued for 24 hours postoperatively. Before, during, as well as after vascular surgery of the lower extremity plasma levels of cortisol, glucose, serotonin (p-5HT), and urinary 5-hydroxyindole-3-acetic acid (5-HIAA) were analysed and platelet aggregability was determined. In the GA group surgery was accompanied by a significant stress response while in the EPI group this stress response was almost completely abolished. Platelet aggregability was reduced intraoperatively in both groups but in the postoperative period there was a marked hyperaggregability only in the GA group. P5HT was increased preoperatively in both groups but was not affected by surgery. It is concluded that epidural anaesthesia, due to its effects on platelet aggregability, may be advantageous for peripheral vascular surgery.