Reproducibility of duplex ultrasonography and air plethysmography used for the evaluation of chronic venous insufficiency.
OBJECTIVE
The purpose of this study was to determine the reproducibility of measurements on duplex ultrasonography (DU) and air plethysmography (APG) in subjects with post-thrombotic syndrome.


METHODS
Duplex ultrasonography and APG were used to measure indices of lower limb venous reflux in 15 limbs with a history of deep vein thrombosis and evidence of venous insufficiency as diagnosed by ultrasonography. Three limbs were in class 0; 4 were in classes 1 to 3; and 8 were in classes 4 to 6, according to clinical, etiologic, anatomic, and pathophysiologic clinical classification. Duplex ultrasonography was performed 3 times on the same day, and venous diameter, area, peak reflux velocity, reflux flow volume, and reflux duration measurements were obtained. Air plethysmography was performed on 2 days, 7 to 10 days apart, with 1 measurement on the first day and 2 measurements on the second day. Values obtained from APG included outflow fraction, venous filling index, ejection fraction, and residual volume fraction. The measurements were performed by a vascular technologist blinded to the previous test results. One-way analysis of variance, the Student paired t test, and Bland-Altman plots were used to examine the statistical differences of the DU and APG parameters for all measurements.


RESULTS
The mean coefficient of variation for within-subject measurements of all DU and APG parameters measured was less than 10%. Bland-Altman plots showed that there were no apparent trends with increasing values over a wide range for any of the DU parameters, nor were there any for the APG parameters.


CONCLUSIONS
Under ideal conditions, when measured by a highly trained technologist, both DU and APG showed satisfactory reproducibility.
Asbeutah
Akram Mahmoud
AM
Department of Vascular Sciences and Medicine, Monash University and Southern Health, Melbourne, Victoria, Australia.
Riha
Andrea Zdena
AZ
Cameron
James Donald
JD
McGrath
Barry Patrick
BP
D000328:Adult; D000368:Aged; D000388:Air; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D015203:Reproducibility of Results; D018616:Ultrasonography, Doppler, Duplex; D014689:Venous Insufficiency / Q000175:diagnosis* / Q000000981:diagnostic imaging*