[The diagnosis of lung embolism].
An accurate diagnosis of pulmonary embolism is essential to prevent excessive mortality and morbidity from lack of therapy or inappropriate anticoagulation. The clinical diagnosis is highly nonspecific because none of the symptoms or signs of pulmonary embolism is unique and all may be caused by other cardiorespiratory disorders. The diagnosis of pulmonary embolism is unlikely, however, if patients do not have dyspnea, tachypnea, evidence of deep vein thrombosis, or a recognized predisposition to thromboembolic disease. Objective testing is mandatory to either confirm or exclude a diagnosis of pulmonary embolism. The electrocardiogram, chest X-ray and the echocardiogram may assist by excluding other potential diagnoses. Routine laboratory studies and lung function testing including blood gas analysis will not be of much help in the differential diagnosis. The hemodynamic investigation with a floating catheter is of diagnostic value especially in those cases where it is not possible to obtain the definitive diagnosis immediately; this method as well as echocardiography can provide a rough estimate of the degree of pulmonary vascular obstruction and are thus able to guide therapy. Methods such as DSA, CT, MR, SPECT, or radiolabelled thrombus scanning are promising but require more extensive validation before routine use. Lung scanning, with its high sensitivity but low specificity is a very useful procedure but cannot be considered to have diagnostic significance independent of the clinical situation. Pulmonary angiography provides the greatest diagnostic certainty of any test available. Based on current knowledge, a diagnostic approach for the management of clinically suspected pulmonary embolism is proposed. Ventilation-perfusion lung scanning is the appropriate next step after ECG, chest X-ray and echocardiogram. The finding of a normal perfusion scan rules out clinically significant embolism and anticoagulation is withheld. Segmental or lobar perfusion defects with normal ventilation in an appropriate clinical setting is sufficiently indicative of pulmonary embolism to proceed with therapy in patients without contraindications. Ventilation-perfusion scans of low or indeterminate probability for pulmonary embolism neither confirm nor exclude the presence of embolism and pulmonary angiography would then be the definitive procedure. As an alternative approach instrumental examination of the leg veins (with venography, impedance plethysmography, or ultrasound) is proposed (Figure 1). If these tests confirm the presence of deep venous thrombosis, anticoagulation can be commenced without the need to perform pulmonary angiography.(ABSTRACT TRUNCATED AT 400 WORDS)
Riedel
M
M
Klinik für Herz- und Kreislauferkrankungen, Deutsches Herzzentrum München.
Rudolph
W
W
D006328:Cardiac Catheterization; D004452:Echocardiography; D004562:Electrocardiography; D006801:Humans; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000209:etiology; D011859:Radiography; D013382:Subtraction Technique
Diagnostik der Lungenembolie.