Prognostic value of repeated thromboelastography measurement for favorable neurologic outcome during targeted temperature management in out-of-hospital cardiac arrest survivors

Background: Cardiac arrest can activate blood coagulation, which clinically manifests as obstruction of the microcirculation and multiple organ dysfunction. Thromboelastography (TEG) provides a rapid and comprehensive assessment of hemostatic processes, but there are limited data on the use of sequential TEG values during targeted temperature management (TTM) in out-of-hospital cardiac arrest (OHCA) survivors. The aim of this study was to investigate the prognostic value of coagulopathy assessed by repeated TEG to predict neurologically intact survival.

Methods: A prospective cohort of consecutive non-trauma OHCA patients who were successfully resuscitated and treated with TTM. Patients with a target temperature of 36 ℃, no TEG data, and who declined appropriate treatment were excluded. TEG was measured at three time points of TTM (initial phase, target phase, and rewarming phase). The primary outcome was 28 day favorable neurologic function, defined as a Cerebral Performance Category of 1 or 2.

Results: A total of 125 patients (mean age, 61 years; 63.2% male) were analyzed. A favorable neurologic outcome at 28 days was seen in 40 patients (32.0%). TEG values of R and LY30 in the initial phase were significantly lower in the favorable neurologic outcome group than in the unfavorable group (5.8 vs. 8.1 and 0.1 vs. 0.7, respectively; p < 0.01). TEG values of R < 5 or LY30 < 7.5 in the initial phase were more frequently seen in the favorable outcomes group than in the unfavorable group (37.5% vs. 12.9%, p = 0.002 and 95.0% vs. 72.9%, p = 0.004, respectively). However, no significant differences were seen between the two groups in other TEG values (R, K, alpha, and MA) in the target and rewarming phases (p > 0.05 for all). Univariate analysis showed higher D-dimer levels, prothrombin time, and activated partial thromboplastin time in the unfavorable outcome group. In the multivariable analysis, TEG values of combination of R < 5 and LY30 < 7.5 in the initial phase were the only coagulation profiles seen to be independently associated with favorable neurologic outcome (OR, 4.508, 95% CI, 1.254-16.210).

Conclusion: TEG results are available within minutes, and shorted R values or the absence of prolonged LY30 values in the initial phase are an early predictor of neurologically intact survival in successfully resuscitated OHCA patients.