Haemostasis during infrarenal aortic aneurysm surgery: Effect of volume loading and cross-clamping

Objectives:To study thrombin and plasmin activation during elective abdominal aortic aneurysm surgery.Design:Prospective study.Setting:University Hospital.Materials:Nine consecutive patients undergoing elective surgery were included. The mean age was 72 years (range 60–79). Blood samples were drawn: (1) before induction of anaesthesia; (2) after induction and Swan Ganz catherisation; (3) just before cross-clamping; (4) before declamping; (5) 8 h postoperatively; (6) 18 h postoperatively.Chief outcome measures:Assays included: prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, prothrombin fragments (F 1 + 2), anti-thrombin III (ATIII), plasminogen, α2-antiplasmin, haematocrit, platelet and serum protein for correction of haemodilution. Data were expressed as mean (s.d.). Differences between mean values were tested by means of the ANOVA for repeated measures and the Wilcoxon signed rank test.Main results:The APTT and TT did not change until heparinisation. The F 1 + 2 were already elevated preoperatively. After correction for haemodilution the AT III and α2-antiplasmin decreased in time (p = 0.009 and 0.0023, respectively) and the F1 + 2 increased (p < 0.0001). Postoperatively (t5 and 6) the values normalised again.Conclusions:The coagulation and fibrinolytic systems are activated during and after elective aortic replacement. Standard tests, like the prothrombin and partial thromboplastin time, are unreliable when assessing the coagulation status of the patient