Occlusive impedance plethysmography. A noninvasive method of diagnosis of proximal deep vein thrombosis.

The purpose of this study was to assess and confirm the accuracy of impedance plethysmography (IPG) by the occlusive cuff method, in detecting proximal (popliteal, femoral and iliac) deep vein thrombosis in patients with symptomatic limbs. In 27 patients 30 consecutive limbs were studied with concurrent venography and IPG. The IPG result was normal in 9 of 9 limbs which were normal on venography, and abnormal in 15 of 16 limbs which showed venographic evidence of proximal deep vein thrombosis (DVT). An abnormal IPG strongly suggests proximal DVT (predictive value 0.88). A normal IPG virtually rules out proximal DVT (predictive value 1.0).