The incidence of pulmonary embolism during deep vein thrombosis

Among life-threatening cardiovascular diseases, pulmonary embolism (PE) is the third most common after myocardial infarction and stroke. PE is a manifestation of venous thromboembolism (VTE). PE shares risk factors with deep vein thrombosis (DVT) and is regarded as a consequence of DVT rather than a separate clinical entity. Risk factors for VTE include major surgery, major trauma, high age, myocardial infarction, chronic heart failure, prolonged immobility, malignancy, thrombophilia and prior VTE. It is, however, important to recognize that these factors are not equally important and not equally common in patients with PE and DVT, respectively. Compared with DVT, PE is more often associated with major surgery, major trauma, high age, myocardial infarction and chronic heart failure, whereas malignancy and thrombophilia primarily are clinical predictors of DVT. In patients with prior VTE the initial clinical manifestation strongly predicts the manifestation of recurrent episodes, i.e. patients with previous PE are more likely to develop recurrent PE than DVT while patients with DVT predominantly are at risk of recurrent DVT.