The Effect of Aspirin and Enoxaparin on the Prevention of Venous Thromboembolism in Patients With Ankle Sprain and Cast Immobilization: A Randomized Clinical Trial

Abstract

Background: The incidence of Venous Thromboembolism (VTE) and its prophylaxis in patients with an ankle injury and cast immobilization are controversial. Objectives: This study aimed to investigate the effect of aspirin and enoxaparin on VTE prevention in patients with an ankle sprain and cast immobilization. Methods: In a double-blind, randomized clinical trial, 90 eligible patients were divided into three groups: patients who did not receive the drugs (the control group), patients who received aspirin (325 mg/d) for 3 weeks (the ASA group), and patients who received enoxaparin (40 mg/d subcutaneously) for 3 weeks (the enoxaparin group). After 3 weeks, the plaster was opened, and the D-dimer level was measured if there was a VTE symptom during the study. Otherwise, at the end of the study, the bilateral lower-limb Complete Compression Ultrasonography (CCUS) and color Doppler ultrasound were used to image the lower limb venous system. Results: Sixty-eight patients completed the study. The mean±SD values of D-dimer in the control, ASA, and enoxaparin groups were 0.33 (0.47) μg/dL (Median=0.18 μg/dL), 0.32 (0.14) μg/dL (Median=0.3 μg/dL) and 0.32 (0.25) μg/dL (Median=0.21 μg/dL), respectively (P>0.05). The positive D-dimer was seen in 2 patients (8%) of the control group, 2 patients (8.3%) of the ASA group, and 2 patients (10.5%) of the enoxaparin group (P>0.05). The color Doppler ultrasound was negative in all patients. Conclusion: Because none of the 68 patients in the current study developed VTE during our 30 days follow-up period, it seems that prophylaxis treatment is unnecessary in patients with an ankle sprain and cast immobilization. Further studies on more patients with a longer period of follow-up are recommended.