Isolated distal deep vein thrombosis: Diagnosis and management.

Isolated distal deep vein thrombosis (IDDVT), a subtype of lower extremity deep vein thrombosis (DVT), is a common yet preventable complication in clinical practice. Based on thrombus location, IDDVT can be categorized into axial venous thrombosis (involving the anterior tibial, posterior tibial, and peroneal veins) and intermuscular venous thrombosis (affecting the venous plexus of the gastrocnemius and soleus muscles). IDDVT is recognized as a potential source of embolic events and is associated with poor prognosis. Current evidence indicates that the Wells score is not applicable for IDDVT diagnosis, which primarily relies on D-dimer testing and lower extremity venous ultrasonography. There remains a lack of standardized treatment protocols for IDDVT. The American College of Chest Physicians (ACCP) guidelines recommend a 3-month anticoagulation regimen for patients with significant symptoms or high risk of thrombus extension, prioritizing direct oral anticoagulants; however, the supporting evidence is of low quality. Significant anatomical and physiological differences exist between axial and intermuscular venous thrombosis. Axial venous thrombosis demonstrates higher rates of thrombus extension, recurrence, and pulmonary embolism compared to intermuscular venous thrombosis. Nevertheless, whether anticoagulation therapy is warranted for both types remains controversial. This narrative review systematically elucidates the epidemiological characteristics, risk factors, clinical manifestations, and clinical management of IDDVT. It focuses on the diagnosis and management of IDDVT based on current guideline recommendations and the latest evidence, with the aim of providing a reference for clinical practitioners.