Prospective 12-year follow-up study of clinical and hemodynamic sequelae after deep vein thrombosis in low-risk patients (Zürich study)

No prospective study of the long-term sequelae of more than 10 years after acute deep vein thrombosis exists so far. Therefore, 58 low-risk patients with DVT were included in a prospective study to evaluate the natural history of postthrombotic syndrome. Clinical and hemodynamic examinations were performed at the time of admission; after 3, 6, and 12 months; after the 2nd, 3rd, 4th, 5th years; and finally after the 12th year. All patients received heparin initially and oral anticoagulants subsequently. After 12 years, 64% of the patients exhibited normal findings. Mild skin changes were found in 28%, marked trophic changes in 5%, and only one venous ulcer occurred. Regular use of compression stockings was reported by 54% of the patients with multilevel thrombosis. Although mean maximum venous outflow was significantly reduced from the acute event to 12 years later (P