Assessment of thrombin generation measured before and after cardiopulmonary bypass surgery and its association with postoperative bleeding

Abstract

Assessment of thrombin generation measured before and after cardiopulmonary bypass surgery and its association with post-operative bleeding.J Thromb Haemost 2011; 9: 282-92.Summary. Background: Bleeding after cardiopulmonary bypass (CPB) is a major cause of morbidity and mortality and consumes large amounts of blood. Identifying patients at increased risk of bleeding secondary to hemostatic impairment may improve clinical outcomes by allowing early intervention. Methods: This present study recruited 77 patients undergoing CPB and measured coagulation screens, coagulation factors, TEG Ò , Rotem Ò and thrombin generation (TG) before surgery and 30 min after heparin reversal. The tests were analyzed to investigate whether they identified patients at increased risk of excess bleeding (defined as > 1000 mL) in the first 24 h postoperatively. Results: Patients who bled > 1000 mL had a lower: platelet count (P < 0.02), factors (F)IX, X and XI (P < 0.005), endogenous thrombin potential (ETP) and an initial rate of TG (P < 0.02) and higher activated partial thromboplastin time (aPTT) (P < 0.001) than patients who bled < 1000 mL. Receiver operating characteristic (ROC) analysis was significant for post-operative TG and aPTT (P < 0.001). Furthermore, reduced pre-operative TG was associated with increased postoperative bleeding (P < 0.02). Pre-and postoperative TG were correlated (q = 0.7, P < 0.001). TEG Ò , Rotem Ò and prothrombin time (PT) at either time point were not associated with increased bleeding. Conclusion: These data suggest that pre-operative defects in the propagation phase of hemostasis are exacerbated during CPB, contributing to bleeding post-CPB. TG taken both pre-and postoperatively could potentially be used to identify patients at an increased risk of bleeding post-CPB.

In vitro assessment, using thrombin generation, of the applicability of prothrombin complex concentrate as an antidote for Rivaroxaban

“…This raises the question of which assay or assay parameter [19][20][21] corresponds best to bleeding or thrombosis risk in patients treated with Rivaroxaban and subsequently antagonized with PCC. Whether or not the persistent delaying effect of Rivaroxaban on PT and lag time is associated with bleeding complications and whether or not AUC normalization by PCC is indeed associated with reversal of Rivaroxaban anticoagulation in vivo remains unclear until prospective patient data are available [22,23].…”

The association between rotational thromboelastometry parameters and blood loss after cardiac surgery with cardiopulmonary bypass

“…Excess bleeding was defined as >1000 mL within the initial 24 h for two reasons. This volume of blood loss has been previously used as a definition of excessive bleeding after CPB, 17,18 and additionally 1000 mL represents the 75th percentile of the patient population in this study. AUCs of ROTEM parameters were compared with the highest AUC of the routine laboratory parameters, to evaluate whether the difference in AUC was statistically significant.…”

Prothrombin Complex Concentrates for Bleeding in the Perioperative Setting

“…37 Reduced preoperative thrombin-generating capacity has strongly correlated with increased postoperative bleeding (r = 0.7, P < 0.001), illustrating the predictive value of this assay. 39 Low values of peak thrombin generation were predictive of blood loss after CPB in a study of 30 patients undergoing coronary artery bypass graft surgery, when thrombin generation was measured both before heparinization and after an appropriate dose of protamine had been administered. 28 Similarly, during pediatric cardiac surgery, thrombin generation variables were uniformly improved after platelet and cryoprecipitate transfusions.…”