Seminars in vascular medicine
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The requirement for a safe diagnostic strategy should be based on an overall posttest incidence of venous thromboembolism (VTE) of less than 1% during 3-month follow-up. The negative predictive value (NPV) during 3 months of follow-up is 98.1 to 99% after a normal venogram, 97 to 98% after a normal compression ultrasonography (CUS), and > 99% after serial CUS testing. Serial CUS testing is safe but 100 CUS must be repeated to find one or two CUS positive for deep vein thrombosis (DVT), which is not cost-effective and indicates the need to improve the diagnostic workup of DVT by the use of clinical score assessment and D-dimer testing. ⋯ A normal perfusion lung scan and a normal rapid ELISA VIDAS D-dimer test safely excludes PE. Helical spiral computed tomography (CT) detects all clinically relevant PE and a large number of alternative diagnoses in symptomatic patients with suspected PE and can replace both the ventilation perfusion scan and pulmonary angiography to safely rule in PE and to rule out PE with an NPV of > 99%. The combination of clinical assessment, a rapid ELISA VIDAS D-dimer, followed by CUS will reduce the need for helical spiral CT by 40 to 50%.
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Recent advances in the management of patients with suspected venous thromboembolism have both improved diagnostic accuracy as well as made management algorithms safer and more accessible. It is now clear that determination of clinical probability prior to diagnostic testing will improve patient management. ⋯ Imaging test interpretation benefits from consideration of pretest probability also as this helps clinicians determine when a test may be falsely negative or falsely positive. Diagnostic strategies should include pretest clinical probability, D-dimer assays, and noninvasive imaging tests.