Coagulation Status Using Clot Wave Analysis in Patients With Prolonged Immobilization

Background Prolonged immobilization is widely recognized as a risk factor for thromboembolism. In this prospective study, we investigated the changes in clot waveform analysis (CWA) parameters in prolonged immobilized patients following lower limb trauma. CWA is an advanced method for assessing global coagulation that involves continuously monitoring changes in light transmittance, absorbance, or light scattering during routine clotting tests. Additionally, we also aim to determine the CWA parameters between day one and after day three of immobilization. Methods A total of 30 patients with prolonged immobilization were enrolled in this study. The plasma of these patients was collected on the first day of their admission and subsequently obtained again after day three of immobilization. Prothrombin time (PT)-based CWA and activated partial thromboplastin time (aPTT)-based CWA were performed using the ACL TOP 300 CTS (Werfen: Bedford, USA) coagulation analyzer, which utilizes the optical method for clot detection. Plasma samples for 20 normal controls were recruited from a healthy blood donor. The CWA parameters generated during clot formation were analyzed. For the comparison of CWA parameters between patients with prolonged immobilization and healthy controls, the Mann-Whitney test was used. A paired t-test was used for the comparison of clot wave parameters between day one and after day three of immobilization. This study was approved by the Universiti Sains Malaysia Research Ethics Committee. Result The mean values of PT and aPTT in healthy controls were 11.66 seconds and 33.98 seconds, respectively. There was no statistically significant difference between the patients and the healthy controls in the median values of aPTT (P=0.935). However, patients with prolonged immobilization exhibited significantly higher median PT CWA parameter values than controls (P=0.007). These parameters included the delta change (P<0.001), peak time velocity (P=0.008), and height velocity (P<0.001). On the other hand, the delta change (P<0.001) and height velocity (P<0.001) of the aPTT CWA parameters were significantly higher in patients with prolonged immobilization than in controls. In patients with prolonged immobilization, there was no significant difference in PT CWA parameters between day one and after day three of immobilization, while for aPTT CWA, all parameters were higher on day three, except for the endpoint time. Conclusion Patients with prolonged immobilization exhibit increased PT and aPTT CWA parameters compared to normal controls. CWA parameters could aid in identifying patients at risk of developing thrombosis through changes in the clot waveform. However, further study is needed to fully utilize additional information from routine coagulation testing.