Follow-up after deep venous thrombosis in azygos continuation

Background: To determine the sequelae of patients after deep venous thrombosis in patients with azygos continuation defined as agenesis of the inferior vena cava with collateral flow. Patients and methods: Five patients post deep venous thrombosis in the context of azygos continuation were followed up clinically and with colour duplex ultrasonography. Results: All five patients had to our knowledge after the initial deep venous thrombosis no further thromboembolic events. Three patients after isolated iliac thromboses are symptom free or nearly symptom free, two after more extended thromboses still suffer from venous claudication. Four patients are without anticoagulation, one patient is permanently orally anticoagulated. Conclusions: Azygos continuation may not influence the risk of recurrent venous thrombo-embolism nor the outcome of a deep venous thrombosis. Careful deep venous thrombosis prophylaxis in patients with azygos continuation may be sufficient when a risk factor is present but conclusions lack due to the small numbers of patients of enough supportive data.