Pulmonary embolism. Guide to diagnosis, treatment, and prevention.
While more remains to be learned about the natural history of deep vein thrombosis and pulmonary embolism, better information is now available on which to base decisions about diagnosis and treatment. Several retrospective and prospective studies have placed the value of lung scanning, venography, and pulmonary angiography in better perspective. Newer diagnostic techniques for deep vein thrombosis, such as 125I-labeled fibrinogen scanning and impedance plethysmography, are valuable and should be more widely used. Other diagnostic techniques for pulmonary embolism, such as computed tomography and nuclear magnetic resonance imaging, may be of value but are still untested. More effective therapies are now available. Moderate-dose subcutaneous heparin and lower-dose warfarin for long-term therapy of deep vein thrombosis are attractive alternatives to standard warfarin therapy. Thrombolytic therapy has not replaced standard intravenous heparin therapy, although it should be considered in treatment of a massive pulmonary embolus. Perhaps most important, prevention of deep vein thrombosis in most patients at high risk is possible with minidose heparin therapy or intermittent pneumatic compression. One of these methods of prophylaxis should be used in all high-risk patients as the only current effective way to decrease the mortality of pulmonary embolism.