Thrombography Reveals Thrombin Generation Potential Continues to Deteriorate Following Cardiopulmonary Bypass Surgery Despite Adequate Hemostasis

Abstract

The intrinsic and extrinsic activation pathways of the hemostatic system converge when prothrombin is converted to thrombin. The ability to generate an adequate thrombin burst is the most central aspect of the coagulation cascade. The thrombin-generating potential in patients following cardiopulmonary bypass (CPB) may be indicative of their hemostatic status. In this report, thrombography, a unique technique for directly measuring the potential of patients’ blood samples to generate adequate thrombin bursts, is used to characterize the coagulopathic profile in post-CPB patients. Post-CPB hemostasis is typically achieved with protamine reversal of heparin anticoagulation and occasionally supplemented with blood product component transfusions. In this pilot study, platelet poor plasma samples were derived from 11 primary cardiac surgery patients at five time points: prior to CPB, immediately post-protamine, upon arrival to the intensive care unit (ICU), 3 hours post-ICU admission, and 24 hours after ICU arrival. Thrombography revealed that the Endogenous Thrombin Potential (ETP) was not different between [Baseline] and [PostProtamine] but proceeded to deteriorate in the immediate postoperative period. At the [3HourPostICU] time point, the ETP was significantly lower than the [Baseline] values, 1233 ± 591 versus 595 ± 379 nM.min (mean ± SD; n = 9, p < .005), despite continued adequacy of hemostasis. ETPs returned to baseline values the day after surgery. Transfusions received, conventional blood coagulation testing results, and blood loss volumes are also presented. Despite adequate hemostasis, thrombography reveals an underlying coagulopathic process that could put some cardiac surgical patients at risk for postoperative bleeding. Thrombography is a novel technique that could be developed into a useful tool for perfusionists and physicians to identify coagulopathies and optimize blood management following CPB.