Acute pulmonary embolism.

Most large or fatal pulmonary embolisms (PE) at autopsy were unsuspected ante mortem. Newly identified clinical characteristics of PE enhance our ability to identify potential patients. Because of laudable efforts to diagnose PE, about 90% of outpatient computed tomographic (CT) angiograms are negative. Overuse of CT angiography has resulted in huge expenses and exposure of many to radiation. Approximately 30% of patients with suspected acute PE would not need imaging if D-dimer is normal and clinical assessment is not a high probability, but such triage is uncommonly used. Perhaps perfusion imaging should be used more frequently. Radiation and cost with scintigraphy are less than with CT angiography. Single-photon emission computed tomography lung scans appear to be more effective than planar lung scans. Diseases associated with an increased risk of PE are being identified, but recommended prophylaxis usually is not given. Potential benefits and risks of treatment options need to be assessed.