Should Patients with Isolated DVT of the Calf Be Anticoagulated?

Approaches to managing acute isolated calf deep venous thrombosis (DVT) range widely and include no treatment, repeat imaging, and therapeutic anticoagulation of varying durations. In a single-center, observational study, researchers evaluated whether therapeutic anticoagulation after a diagnosis of isolated calf DVT decreases the risk for a proximal DVT or pulmonary embolism (PE).

Of the 384 patients with acute isolated calf DVT (mean age, 60; 58% men), 243 were intended for therapeutic anticoagulation and 141 were not (controls). Therapeutic anticoagulation consisted of warfarin in 75%, a low-molecular-weight heparin in 18%, heparin infusion in 6%, and a direct-acting oral anticoagulant in 1%.

Overall, a proximal DVT or PE occurred in 13 controls and 8 anticoagulated patients; median time to proximal DVT was 13 days, and median time to PE was 15.5 days. The relative risk with anticoagulation for progression to DVT or PE was 0.36. The analysis was similar in patients with provoked calf DVT (odds ratio, 0.35). Therapeutic anticoagulation was significantly associated with lower risk when calf DVT involved the muscular branch veins — the gastrocnemius and soleal veins (OR, 0.12) — and not the anterior or posterior tibial veins or peroneal veins. A higher percentage of patients in the anticoagulated group experienced clinically significant bleeding.