Frequency of Pulmonary Embolism in Patients with Low-Probability Lung Scan and Negative Lower Extremity Venous Ultrasound

Study objectivesTo define the prevalence of pulmonary embolism (PE) in patients who are undergoing pulmonary arteriography because of a high clinical suspicion for PE but who have had a low-probability lung scan and a negative lower extremity venous ultrasound examination.DesignA retrospective review of the medical records of 365 consecutive patients who underwent pulmonary arteriograms for suspected PE was undertaken.ResultsOf the 365 pulmonary arteriograms, 62 were performed in patients with suspected PEs despite a low-probability lung scan and a negative lower extremity venous ultrasound examination. In the latter group, five patients (8%; 95% confidence interval, 2.7% to 18%) had PEs revealed on the arteriogram.ConclusionsIn patients whose presentation provokes a high clinical suspicion for PE despite having had a low-probability lung scan, a negative lower extremity venous ultrasound examination is insufficient to preclude proceeding to pulmonary angiography.