Therapeutic and economic implications of emergency department evaluation for venous thrombosis

Records of 160 emergency department patients with lower extremity complaints were reviewed to determine the economic and therapeutic impact of noninvasive venous impedance testing. Venograms obtained in 86 extremities were used to determine diagnostic accuracy. The incidence of pulmonary thromboembolic events, postphlebitic syndrome and complications of anticoagulation was ascertained. Outflow impedance testing correctly identified all patients with deep venous thrombosis and overall diagnostic accuracy was 95% (41/43 patients). In 123 patients (33 positive results, 90 negative) therapeutic decisions were based solely on impedance test results. Examination required 20 to 30 minutres at a cost of $35. Follow-up ranging from 4 to 60 weeks failed to reveal documented thromboembolic complications or recurrence of lower extremity symptoms. In 37 patients (six positive results, 31 negative) impedance test results were ignored and inpatient workup, including invasive venography, was undertaken. Hospital charges for these patients averaged $1,500. In addition to its ease of performance and high degree of accuracy, comparison with inpatient evaluation documents its cost effectiveness. Impedance testing for emergency department evaluation of suspected deep vein thrombosis appears appropriate.