Thromboelastography for monitoring prolonged hypercoagulability after major abdominal surgery

Despite clinical and laboratory evidence of perioperative hypercoagulability, there are no consistent data evaluating the extent, duration, and specific contribution of platelets and procoagulatory proteins by in vitro testing. We tested the hypothesis that the parallel use of standard and abciximab-cytochalasin D-modified thromboelastography (TEG) can assess 7 days' postoperative hypercoagulability and can estimate the independent contribution of procoagulatory proteins and platelets. Thromboelastograms were performed before surgery, at the end of surgery, 6 h after surgery, and on postoperative days 1, 2, 3, and 7; they were analyzed for the reaction time and the maximal amplitude (MA). We calculated the elastic shear modulus of standard MA (G(t)) and modified MA (G(c)), which reflect total clot strength and procoagulatory protein component, respectively. The difference was an estimate of the platelet component (G(p)). There was a 10% perioperative increase of standard MA, corresponding to a 50% increase of G(t) (P < 0.0001) and an 86%-90% contribution of the calculated G(p) to G(t). We conclude that serial standard and modified thromboelastography may reveal prolonged postoperative hypercoagulability and the independent contribution of platelets and procoagulatory proteins to clot strength.

Postoperative hypercoagulability, occurring for at least 1 wk after major abdominal surgery, may be demonstrated by standard and modified thromboelastography. This hypercoagulability is not reflected by standard coagulation monitoring and seems to be predominantly caused by increased platelet reactivity.