Diagnosis and management of pulmonary embolism.

The prevalence of acute pulmonary embolism in a general hospital was evaluated. Importantly, the prevalence of unrecognized pulmonary embolism at autopsy has not changed in three decades. Further evaluation was made of the alveolar-arterial oxygen difference in the diagnosis of acute pulmonary embolism. As with the partial pressure of oxygen in arterial blood, the alveolar arterial oxygen difference is usually abnormal, but a normal value does not exclude pulmonary embolism. The criteria used for a low probability interpretation of ventilation-perfusion lung scans in the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) were modified. Criteria for a very low probability assessment (< 10% positive predictive value) were also determined. Progress was made with helical computed tomography and contrast-enhanced electron-beam computed tomography, but with present technology their role is limited. Selective digital subtraction angiography with a flow directed catheter seems to have been useful in some patients. A strategy for diagnosis of thromboembolic disease that uses serial noninvasive leg tests was described. The strategy reduces the number of pulmonary angiograms required. The Fourth American College of Chest Physicians Conference on Antithrombotic Therapy was published. Extensive and detailed analysis was made of the literature related to the antithrombotic treatment of pulmonary embolism and the use of antithrombotic therapy during pregnancy.