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Updated: Jun 11, 2026
Leveraging Turbidity and Thromboelastography for Complementary Clot Characterization
Published on: June 4, 2020
Differentiation of enzymatic from platelet hypercoagulability using the novel thrombelastography parameter delta
Eduardo Gonzalez1, Jeffry L Kashuk, Ernest E Moore
1Department of Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, Colorado, USA.
Background:
Thrombelastography (TEG) allows for rapid global assessment of coagulation function. Our previous work demonstrated that a hypercoagulable state identified by TEG's G value was associated with thromboembolic events in a cohort of critically ill surgical patients despite routine chemoprophylaxis. We hypothesized that a hypercoagulable state could be differentiated into enzymatic or platelet etiology through the use of thrombus velocity curves; specifically the time to maximum rate of thrombus generation (TMRTG) and the novel TEG parameter, delta. (Delta)
Methods:
We retrospectively studied 10 critically ill surgical patients receiving thromboprophylaxis for at least 72 h by TEG, using kaolin activated citrated samples. Thrombus velocity curves were plotted for each patient, and delta was calculated as the difference between the TEG parameters R and SP, corresponding to the time to maximum rate of thrombus generation (TMRTG), which reflects the enzymatic contribution to clot formation. The TEG parameter G, (G = 5000 x A/100-A) also was determined for each patient. As G is derived from amplitude (A), it reflects overall net clot strength. A hypercoagulable state was defined as delta < 0.6 min and/or G > 11 dynes/cm(2).
Results:
A hypercoagulable state was identified via delta in 6 patients (60%); all of whom remained hypercoagulable following heparinase addition, suggesting chemoprophylaxis was ineffective. Of six patients with a hypercoagulable G value, 50% had a normal delta suggesting the presence of platelet hypercoagulability. Delta closely correlated with TMRTG (r = 0.94). However, the varying contribution of platelets to hypercoagulability, was shown by a nonlinear, weak correlation of delta and TMRTG with G (r = 0.11 and r = 0.14, respectively).
Conclusion:
Delta reflects changes in thrombin generation as measured by TMRTG, allowing for differentiation of enzymatic from platelet hypercoagulability. Future studies will be required to validate these findings.
