Non-invasive diagnostic work-up patients with clinically suspected pulmonary embolism; results of a management study

Background: Clinicians often deviate from the recommended algorithm for the diagnosis of pulmonary embolism consisting of ventilation-perfusion scintigraphy and pulmonary angiography. Objectives: To assess the safety and feasibility of a diagnostic algorithm which reduces the need for lung scintigraphy and avoids the use of angiography. Patients and methods: Consecutive patients with a clinical suspicion of pulmonary embolism were prospectively investigated according to an algorithm in which the diagnosis of pulmonary embolism was excluded after a low clinical probability estimate and a normal D-dimer test result, a normal perfusion scintigraphy result, or a non-high probability scintigraphy result in combination with normal serial ultrasonography of the legs. In these patients anticoagulant treatment was withheld and they were followed up for 3 months to record possible thromboembolic events. During the study period, 923 consecutive patients were seen, of whom 292 were excluded because of predefined criteria. Results: Of the 631 included patients, the diagnosis was refuted on the basis of a low clinical probability estimate and a normal D-dimer test result (95 patients), normal perfusion scintigraphy (161 patients) and non-high probability lung scintigraphy followed by normal serial ultrasonography (210 patients). Of these 466 patients, venous thromboembolic complications during follow-up occurred in six (complication rate 1.3%, 95% confidence interval 0.5, 2.8). The diagnostic protocol was completed in 92% of all included patients. Conclusion: The diagnosis of pulmonary embolism can be safely ruled out by a non-invasive algorithm consisting of D-dimer testing combined with a clinical probability estimate, lung scintigraphy, or serial ultrasonography of the legs (in case of non-diagnostic lung scintigraphy).