The clinical significance of pulmonary embolism: uncertainties and implications for treatment--a debate.

Pulmonary embolism and deep vein thrombosis are different aspects of a single problem, thromboembolic disease, which is frequently asymptomatic. The incidence and clinical significance of thromboembolic disease is uncertain. The mortality of untreated pulmonary embolism is unknown but may be much lower than is generally thought. Investigation of the lower limbs is desirable in most cases, even when there are no symptoms in the legs, in order to evaluate the prognosis and the need for anticoagulant therapy. Not all cases of pulmonary embolism require treatment. The presence or absence of risk factors may be important in determining the appropriate length of treatment.