Pulmonary embolism: from clinical presentation to clinical probability assessment.

The rehabilitation of clinical assessment of venous thromboembolism (VTE) is certainly one of the major breakthroughs of the last decade in the field of pulmonary embolism (PE) diagnosis. Although the value of isolated clinical findings in suspected PE is limited due to the poor sensitivity and specificity of its symptoms and signs, their combination, whether empiric or explicit through prediction rules, allows a fairly accurate assessment of the likelihood of the disease in a given patient. This allows the identification of a large subset of patients with a low prevalence of the disease in whom a combination of noninvasive tests rules out PE effectively despite these tests' limited individual sensitivity. The best validated example is the combination of a low probability lung scan and a normal venous compression ultrasound in a patient with low clinical probability of PE, which is associated to a low 1 to 2% 3-month risk of VTE in such patients left untreated by anticoagulants. Finally, clinical assessment contributes significantly to the cost savings associated with modern noninvasive strategies.