Venous thromboembolism is one clinical entity, which may show a variety of clinical pictures. On the one hand, deep vein thrombosis is a well-recognised clinical problem. However, in patients with proven DVT up to 50% already have (often silent) pulmonary embolism at presentation. On the other hand, pulmonary embolism is a feared clinical problem. In patients with proven PE 70-90% have demonstrable DVT in the deep leg veins.