Risk Factors
The most common sources of embolism are proximal leg deep venous thrombosis (DVTs) or pelvic vein thromboses. Any risk factor for DVT also increases the risk that the venous clot will dislodge and migrate to the lung circulation, which may happen in as many as 15% of all DVTs. The conditions are generally regarded as a continuum termed venous thromboembolism (VTE).
The development of thrombosis is classically due to a group of causes named Virchow's triad (alterations in blood flow, factors in the vessel wall and factors affecting the properties of the blood). Often, more than one risk factor is present.
- Alterations in blood flow: immobilization (after surgery, injury, pregnancy (also procoagulant), obesity (also procoagulant), cancer (also procoagulant)
- Factors in the vessel wall: of limited direct relevance in VTE
- Factors affecting the properties of the blood (procoagulant state):
- Estrogen-containing hormonal contraception
- Genetic thrombophilia (factor V Leiden, prothrombin mutation G20210A, protein C deficiency, protein S deficiency, antithrombin deficiency, hyperhomocysteinemia and plasminogen/fibrinolysis disorders)
- Acquired thrombophilia (antiphospholipid syndrome, nephrotic syndrome, paroxysmal nocturnal hemoglobinuria)
- Cancer (due to secretion of pro-coagulants)
Read more about this topic: Pulmonary Embolism
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