Features of Thrombi and Diagnostic Accuracy of Impedance Plethysmography in Symptomatic and Asymptomatic Deep Vein Thrombosis

Impedance plethysmography (IPG) has high sensitivity and specificity in patients with symptomatic deep vein thrombosis (DVT) while it fails to detect asymptomatic DVT. The aim of this study was to determine whether the features of thrombi such as location, size and occlusiveness could explain the different accuracy of IPG in symptomatic and asymptomatic DVT patients. One-hundred and seventeen consecutive outpatients with a clinical suspicion of DVT and 246 consecutive patients undergoing hip surgery were admitted to the study. In symptomatic patients IPG was performed on the day of referral, followed by venography, while in asymptomatic patients IPG was performed as a surveillance programme, followed by bilateral venography