Accuracy of Venous Filling Index on Standing (VFIst) and Pure Regurgitation Index (PRI), a Novel Index Obtained by Air Plethysmography, for Detecting Venous Reflux

Abstract

Objective To evaluate the accuracy of venous filling index on standing (VFIst) and a new index named pure regurgitation index (PRI), obtained by air plethysmography, for detecting venous reflux. Materials and methods One hundred and sixty-one healthy subjects (161 limbs) and 180 varicose vein patients (180 limbs) were investigated. All subjects underwent duplex ultrasonography for verifying venous reflux and air plethysmography to obtain hemodynamic parameters such as VFIst, VFI in the supine position (VFIsu), and the maximum arterial inflow rate. To evaluate the accuracy of VFIst and PRI (= (VFIst - VFIsu)/body mass index), receiver operating characteristics curves were created. Results The optimal cut-off value, sensitivity, specificity, and area under the curve, obtained from analyzing the receiver operating characteristics curves, of VFIst vs. PRI were 2.058 mL/s vs. 0.059 mL · m(2)/s · kg, 93.3% vs. 90.3%, 88.8% vs. 91.3%, and 0.954 vs. 0.964, respectively. Conclusions This study indicates that while both VFIst and PRI are highly accurate indicators of venous reflux, PRI, which is not affected by the arterial inflow rate and body mass index, is slightly superior to VFIst, especially in subjects with greater body mass index.