Non‐invasive diagnostic work‐up of 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).