Comparison of venous reflux assessed by duplex scanning and descending phlebography in chronic venous disease.

Venous reflux was assessed by duplex scanning and descending phlebography in 98 limbs of 52 patients. There was moderately good agreement for deep vein reflux elicited by a standardised Valsalva manoeuvre, classified by a modified Kistner grading (0 to IV). The same grade was found in 58 limbs, with a difference of one grade in 27 limbs, and more than one grade in 13. Descending phlebography underestimated reflux in the lower leg compared with duplex scanning. The presence of reflux found on duplex scan correlated with the half-volume refilling time on a foot-volume plethysmogram with a below-knee tourniquet. There was no correlation between descending phlebography and the half-refilling time. Ascending phlebography showed post-thrombotic changes in 23 limbs. The duplex scan confirmed severe reflux (grades III and IV) in 14 of these 23 limbs, and demonstrated isolated reflux below normal valves in 4 other limbs. Severe reflux was seen on the descending phlebogram in only 10 of the 23 limbs with post-thrombotic changes. Duplex scanning may be a better method for detecting reflux than descending phlebography and is more acceptable to the patient. Ascending phlebography remains essential to display anatomical abnormalities found in some postthrombotic limbs that are not associated with reflux.