Residual vein obstruction in patients diagnosed with acute isolated distal deep vein thrombosis associated with active cancer

After acute proximal deep vein thrombosis (DVT) the thrombotic mass decreases, especially during the first months of anticoagulation. The persistence of residual vein obstruction (RVO) may predict future recurrence in patients with cancer-associated DVT. We aimed to evaluate the proportion of patients with RVO after an episode of cancer associated isolated distal DVT (IDDVT), to identify variables associated with RVO, and to provide initial evidence of its association with recurrent VTE. We performed a post-hoc analysis of a multicenter cohort study of patients with isolated cancer-associated acute IDDVT. We included patients who underwent a control ultrasonography at the end of the anticoagulant treatment between day 30 and day 365 after index IDDVT, given that no recurrent VTE had already occurred on anticoagulant treatment. A total of 153 patients had ultrasonographic follow-up after a median of 92 days from index IDDVT: 45.8% had RVO and 54.2% exhibited complete recanalization. Female sex, Body Mass Index > 30 Kg/m² and involvement of axial calf veins showed the strongest association with RVO. The risk of recurrence was twofold higher in patients with (versus without) RVO. RVO persisted in approximately half of patients with an episode of cancer-associated IDDVT at anticoagulant discontinuation. Patients with RVO appeared to be at a higher risk for recurrent events.