Natural History of Isolated Below-Knee Vein Thrombosis in Patients with Spinal Cord Injury

In the general population, serial imaging is recommended over anticoagulant therapy for below-knee deep vein thrombosis (BKDVT). However, no clinical trial in Asian patients with spinal cord injury and BKDVT has been performed. Therefore, we evaluated the natural course of BKDVT in patients with acute spinal cord injury. We retrospectively analyzed inpatients with spinal cord injury with BKDVT between 2016 and 2020. All patients underwent inpatient rehabilitation treatment and duplex ultrasonographic examination of both the lower extremities at follow-up. After screening 172 patients with acute spinal cord injury for deep vein thrombosis using duplex ultrasound, 27 patients with below-the-knee deep vein thrombosis were included in this study. The mean lower-extremity motor score (median, interquartile range) was 66.0, 54.0–74.5. Sixteen patients received a non-vitamin K antagonist oral anticoagulant (NOAC) for anticoagulation. None of the patients had proximal propagation according to the follow-up duplex ultrasonography. BKDVT disappearance was not significantly different between the NOAC treatment and non-treatment groups. Asian patients with spinal cord injury have a low incidence of venous thromboembolism and favorable natural history of BKDVT. We recommend serial imaging over anticoagulant therapy for BKDVT in these patients.