Diagnostic management of venous thromboembolism

The accuracy of diagnostic methods for the diagnosis of deep vein thrombosi s and pulmonary embolism in symptomatic patients is critically reviewed. In . addition, the safety of withholding anticoagulant therapy from patients w ith suspected deep vein thrombosis or pulmonary embolism in whom the qualif ied diagnostic strategy was normal is evaluated by determining the frequenc y of venous thromboembolic complications during 3 months of follow-up. It i s shown that the currently used available diagnostic techniques for deep ve in thrombosis are all able to identify the majority of patients who indeed have venous thrombosis. However, as result of its accuracy and practical ad vantages, compression ultrasound is the test of choice in the evaluation of symptomatic patients. Patients with a normal test outcome should be re-tes ted to detect the small proportion of patients with proximally extending ca lf vein thrombosis. In the strategy of repeated diagnostic testing, impedan ce plethysmography could be used as an alternative to ultrasonography. To o btain a reduction in repeat tests various diagnostic strategies have been e valuated and it was shown that these strategies, using non-invasive tests, can be as accurate and safe as the invasive reference strategy. The safetie s of the various strategies were very similar; however, important differenc es were observed with respect to the practical implementation of the variou s diagnostic strategies. Simplification of the repeated testing strategy by using a D-dimer assay and/or a clinical decision rule seems to be promisin g. The reference standard for the diagnosis of pulmonary embolism remains p ulmonary angiography. Several strategies based on non-invasive diagnostic m ethods have been evaluated for their safety and complexability. Perfusion-v entilation lung scanning is the most thoroughly evaluated nan-invasive tech nique so far. It seems safe to withhold anticoagulant therapy in patients s uspected of pulmonary embolism with a normal perfusion lung scan result; ho wever, further testing is needed in the case of a non-diagnostic perfusion- ventilation lung scan result. At this moment angiography is the method of c hoice in this category of patients. D-dimer assays, clinical decision rules and ultrasound examinations of the legs seem to have a high potential to l imit the need for angiography. Also, spiral computerized tomography and mag netic resonance imaging are promising techniques, but their role in the dia gnostic management of pulmonary embolism is still uncertain.