Diagnosis of pulmonary embolism in outpatients by sequential noninvasive tools

Considerable progress has been made in pulmonary embolism (PE) diagnosis during the last 10 years. New, noninvasive tools such as D-dimer measurement and lower limb venous compression ultrasonography have been introduced as diagnostic strategies. Clinical evaluation of the likelihood of PE has been rehabilitated and has proven to be accurate and useful. The interpretation of lung scan results has become more standardized and clear to clinicians. Finally, two diagnostic strategies have been validated in large scale outcome studies. Both rely on a sequential combination of the aforementioned instruments and have safely treated more than 90% of patients without use of pulmonary angiography. The 3-month venous thromboembolic risk in patients in whom PE was ruled out and, hence, who did not undergo anticoagulation was less than 1% in both studies. In the absence of a formal comparison of their respective cost-effectiveness, choosing between these strategies rests on local preferences or logistics. Finally, spiral computed tomography (CT) seems promising and might modify the diagnostic work-up of PE in the near future. However, it is insufficiently validated, and its place in a rational diagnostic algorithm is not defined.