Relation of thromboelastography parameters to conventional coagulation tests used to evaluate the hypercoagulable state of aged fracture patients

Abstract

Fractures are common among aged people, and rapid assessment of the coagulation status is important. The thromboelastography (TEG) test can give a series of coagulation parameters and has been widely used in clinics. In this research, we looked at fracture patients over 60 and compared their TEG results with those of healthy controls. Since there is a paucity of studies comparing TEG assessments with conventional coagulation tests, we aim to clarify the relationship between TEG values and the values given by conventional coagulation tests.Forty fracture patients (27 femur and 13 humerus) over 60 years old were included in the study. The change in their coagulation status was evaluated by TEG before surgery within 4 hours after the fracture. Changes in TEG parameters were analyzed compared with controls. Conventional coagulation test results for the patients, including activated partial thromboplastin time (APTT), international normalized ratio (INR), fibrinogen, and platelets, were also acquired, and correlation analysis was done with TEG parameters, measuring similar aspects of the coagulation cascade. In addition, the sensitivity and specificity of TEG parameters for detecting raised fibrinogen levels were also analyzed.The K (time to 20 mm clot amplitude) and R (reaction time) values of aged fracture patients were lower than controls. The values for angle, maximal amplitude (MA), and coagulation index (CI) were raised compared with controls, indicating a hypercoagulable state. Correlation analysis showed that there were significant positive correlations between fibrinogen and MA/angle, between platelets and MA, and between APTT and R as well. There was significant negative correlation between fibrinogen and K. In addition, K values have better sensitivity and specificity for detecting elevated fibrinogen concentration than angle and MA values.Aged fracture patients tend to be in a hypercoagulable state, and this could be effectively reflected by a TEG test. There were correlations between TEG parameters and corresponding conventional tests. K values can better predict elevated fibrinogen levels in aged fracture patients.

Figure 1

Comparison of thromboelastography of fracture patients and healthy control. (A) Represented thromboelastography of fracture patients and the controls. (B) Comparison of four major TEG parameters of the 2 groups. Data are present as mean ± SD. SD = standard deviation, TEG = thromboelastography.

Figure 2

Correlation analysis between TEG parameters and conventional coagulation tests of aged fracture patients. (A) APTT and INR versus TEG R value. Data are present as plots with linear fit, Pearson test r and P values are listed. (B) INR versus TEG R value. Spearman test r and P values are listed. (C, D, G) Fibrinogen concentration versus TEG MA (C), angle (E), and K (G) values. Scatter plots with linear fit are shown and Pearson r and P values are listed. (D, F, H) Platelet count versus TEG MA (D), angle (F), and K (H) values. Data are present as Scatter plots with linear fit, Pearson test r and P values are listed. P values less than 0.05 are regarded as significant. APTT = activated partial thromboplastin time, INR = international normalized ratio, MA = maximal amplitude, TEG = thromboelastography.

Figure 3

ROC curve of TEG parameters for detecting raised concentration of fibrinogen. ROC curves detecting elevated level of fibrinogen (>400 mg/dL) by K, MA, and angle (α) values are present. The AUC and 95%CI are listed. AUC = area under curve, CI = confidence interval, MA = maximal amplitude, ROC = receiver operating characteristics, TEG = thromboelastography.