Saddle pulmonary thromboembolism with zero Wells' score.

A retrospective cohort study of 2,218 patients with deep vein thrombosis or pulmonary embolism during a 25-year period from 1966-1990 in Minnesota showed an annual incidence of venous thromboembolism of 117 per 100,000 (deep vein thrombosis, 48 per 100,000; pulmonary embolism, 69 per 100,000). Higher rates were found in males than females (130 vs 110 per 100,000, respectively) after adjusting for age. Early diagnosis and appropriate treatment of DVT and PE have been shown to significantly reduce mortality and morbidity. Risk factors for venous thromboembolism include alterations in blood flow (surgery, injury or long-distance air travel, pregnancy, obesity), hypercoagulability (factor V Leiden mutation, prothrombin mutation, protein C deficiency, protein S deficiency, antithrombin deficiency, hyperhomocysteinemia, antiphospholipid syndrome, nephrotic syndrome, paroxysmal nocturnal hemoglobinuria) and vessel wall abnormalities. Eighty percent of deep venous thrombosis resolves spontaneously and less than 15% embolize to pulmonary arteries.