PULMONARY embolism (PE) is a common complication that usually afflicts patients who are hospitalized for other medical or surgical problems. Its continued prevalence seems to be the result of increasing numbers of older and sicker patients who are hospitalized and subjected to longer periods of bed rest and more complex operations. Although the true incidence of PE is not known, a reasonable estimate can be made from various studies that suggest that fatal PE occurs in about three to five patients per 1,000 inpatients in a general hospital population, including both hipsurgery patients and patients with malignant neoplasms undergoing surgical procedures, and nonfatal PE occurs in about 15 to 20 patients per 1,000 inpatients.
The mortality of undiagnosed and therefore untreated PE is relatively high, ranging from about 18% to 35%,1 whereas, once diagnosed and treated, a substantial reduction to about 8% occurs. This observation underscores the importance of