Tissue plasminogen activator resistance is an early predictor of posttraumatic venous thromboembolism: A prospective study from the CLOTT research group

BACKGROUND Venous thromboembolism (VTE) remains a frequent postinjury complication with well established but nonmodifiable risk factors. We hypothesized that fibrinolysis shutdown (SD) as measured by thromboelastography (TEG) would be an independent risk factor for VTE in trauma patients. METHODS A subgroup of patients enrolled in the CLOTT-2 (Consortium of Leaders in the Study of Traumatic Thromboembolism 2), multicenter prospective cohort study had kaolin TEG and tissue plasminogen activator (tPA)-TEG data at 12 and 24 hours postadmission. Patients underwent a screening duplex venous ultrasound examination during the first week unless clot was already detected on computed tomography. Injury factors associated with early fibrinolysis SD (defined as kaolin TEG Ly30 ≤0.3%) and/or tPA resistance (tPA-R) (defined as kaolin TEG with tPA 75 ng Ly30 <2.1%) were investigated as was the association of the TEG measurements with the development of VTE. RESULTS A total of 141 patients had both TEG measurements at 24 hours, and 135 had both TEG measurements at 12 hours. Shutdown was evident at 12 hours in 71 of 135 (52.6%) patients and in 62 of 141 (44%) at 24 hours. Tissue plasminogen activator resistance was found in 61 of 135 (45.2%) at 12 hours and in 49 of 141 (34.3%) at 24 hours. Factors significantly associated with SD included receiving >4 U of FFP in the first 24 hours, the presence of a major brain injury or pelvic fracture, and the need for major surgery. In contrast, factors significantly associated with early tPA-R included >4 U of red blood cells transfused in the first 24 hours and the presence of a major chest injury or long bone fracture. Deep vein thrombosis was detected in 15 patients and pulmonary clots in 5 (overall VTE rate, 14.2%). Tissue plasminogen activator resistance at 12 hours was found to be an independent risk factor for VTE (hazard ratio, 5.57; 95% confidence interval, 1.39-22.39). CONCLUSION Early development of a hypercoagulable state as defined by tPA-R at 12 hours after admission represents a potentially modifiable risk factor for postinjury VTE. LEVEL OF EVIDENCE Therapeutic/Care Management; Level II.