[Contribution of laboratory tests and venous investigations in the diagnosis of pulmonary embolism].
The diagnostic strategy of pulmonary embolism is based firstly on pulmonary scintigraphy, a non-invasive investigation which provides a definitive diagnosis in about 30% of patients, and then on pulmonary angiography, which remains the investigation of reference. However, new diagnostic methods have been introduced in order to reduce the number of angiographies. Measurement of plasma D-dimer, a fibrin degradation product, enables exclusion of the diagnosis in 20-50% of patients without pulmonary embolism when the result is normal on ELISA (< 500 micrograms/l with the commercialized Stago test). This is due to the very high sensitivity of D-dimer: in a compilation of recent series with a total of 1,159 patients suspected of having pulmonary embolism, their concentration was over the threshold of 500 micrograms/l in 96% (CI 95%, 93-98) of patients with pulmonary embolism. On the other hand, their low specificity makes them useless for a positive diagnosis of the condition. Lower limb venous compression ultrasonography enables detection of proximal deep venous thrombosis in about 57% (CI 95%, 52-62) of patients with pulmonary embolism, posing the indication for anticoagulation without further investigations because of its high specificity (98%) (CI 95%, 97-99). When venous ultrasonography is normal, however, pulmonary embolism cannot be excluded. A diagnostic strategy associating these two investigations and pulmonary scintigraphy reduces the number of diagnostic angiographies by 30 to 50% according to whether D-dimer and ultrasonography are performed before or after scintigraphy respectively. More extensive use of D-dimer in clinical practice requires more rapid and equally reliable unitary tests as the ELISA.
Perrier
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Clinique de médecine 1, hôpital cantonal universitaire, Genève, Suisse.
Bounameaux
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H
D000933:Antifibrinolytic Agents / Q000097:blood; D003663:Decision Trees; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D010992:Plethysmography, Impedance; D011237:Predictive Value of Tests; D011336:Probability; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis*; D011859:Radiography; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014463:Ultrasonography; D014680:Veins / Q000000981:diagnostic imaging
D000933:Antifibrinolytic Agents; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D