Should We Treat Patients with Isolated Calf Deep Venous Thrombosis?

For isolated deep venous thrombosis (DVT) of the calf, American College of Chest Physicians guidelines suggest (1) anticoagulation in patients with severe symptoms or risk factors for proximal extension, and (2) in lower-risk patients, repeat ultrasound imaging during 2 weeks, plus anticoagulation for those whose DVTs extend proximally (Chest 2016; 149:315). However, data to inform these decisions are limited. In this double-blind trial, researchers in Europe randomized 259 adults with first acute isolated symptomatic calf DVTs, diagnosed by ultrasound, to receive either the low-molecular-weight heparin nadroparin (not available in the U.S.) or placebo for 6 weeks; follow-up visits with repeat ultrasound were scheduled at 3 to 7 days and at…